text: ISL6253 ® Data Sheet August 2004 Highly Integrated Battery Charger for Notebook Computers Features • ±0.5% Voltage Accuracy The ISL6253 is a highly integrated battery charger controller for Li-Ion/Li-Polymer batteries. High Efficiency is achieved by a synchronous buck topology and the use of a MOSFET, instead of a diode, for selecting power from the adapter or battery. The low side MOSFET emulates a diode at light loads to improve the light load efficiency and prevent system bus boosting. The constant output voltage can be selected for 2, 3 or 4 series Li-Ion cells with 0.5% accuracy over temperature. It can also be programmed between 4.2V +5% per cell and 4.2V -5% per cell to optimize battery capacity. When supplying the load and battery charger simultaneously, the input current limit for the AC adapter is programmable to within 3% accuracy to avoid overloading the AC adapter, and to allow the system to make efficient use of available adapter power for charging. It also has programmable charging current with 4% accuracy. The ISL6253 provides outputs that are used to monitor the current drawn from the AC adapter, and to monitor for the presence of an AC adapter. The ISL6253 automatically transitions from regulating current to regulating voltage. A conditioning charge feature provides approximately 10% of full scale charge current to safely charge deeply discharged lithiumion (LI+) battery packs when the battery voltage is below 3.0V/cell. ISL6253 has a feature of automatic power source selection by switching to the battery when the AC adapter is removed or switching to the AC adapter when the AC adapter is available. It also supports aircraft power applications while powering the system and not charging the battery. Ordering Information PART # TEMP. RANGE (°C) PACKAGE FN9117.2 PKG. DWG. # ISL6253HRZ (Note 1) -10 to 100 28 Ld 5x5 QFN (Pb-free) L28.5x5 ISL6253HAZ (Note 1) -10 to 100 28 Ld QSOP (Pb-free) M28.15 • ±3% Input Current Limit Accuracy • ±4% Accurate Battery Charge Current Limit • Programmable Charge Limit Current, Adaptor Current Limit and Charge Voltage • Fixed 300kHz PWM Synchronous Buck Controller with Diode Emulation at Light Load • Output for Current Drawn from the AC Adapter • AC Adapter Present Indicator • Fast Input Current Limit Response • Input Voltage Range 7V to 25V • Up to 17.6V Battery-Voltage Set Point • Trickle Charge Mode When Battery Voltage is below 3.0V/Cell • Supports 2, 3 and 4 Cell Battery Packs • Control Adapter Power Source Select MOSFET • Thermal Shutdown • Aircraft Power Capable • DC Adapter Present Indicator • Battery Discharge MOSFET Control • Less than 10µA Battery Leakage Current • QFN Package - Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat No Leads - Package Outline - Near Chip Scale Package footprint, which improves PCB efficiency and has a thinner profile • Pb-free Available Applications • Notebook, Desknote and Sub-notebook Computers • Personal Digital Assistants NOTES: 1. Intersil Pb-free products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which is compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J Std-020B. 2. Add "-T" for Tape and Reel. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2004. All Rights Reserved All other trademarks mentioned are the property of their respective owners. ISL6253 Pinouts EN ACSET VDD DCIN DCPRN ACPRN CSON ISL6253 (28 LD QSOP) TOP VIEW DCSET ISL6253 (28 LD QFN) TOP VIEW DCIN 28 27 26 25 24 23 22 ACSET 21 1 CSOP CELLS 2 20 CSIN ICOMP 3 19 CSIP VCOMP ICM 18 4 17 5 SGATE BGATE UGATE 8 9 10 11 12 13 14 BOOT 15 VDDP 7 LGATE CHLIM PGND PHASE GND 16 VADJ 6 ACLIM VREF 2 1 28 DCPRN VDD 2 27 ACPRN 3 26 CSON DCSET 4 25 CSOP EN 5 24 CSIN CELLS 6 23 CSIP ICOMP 7 22 SGATE VCOMP 8 21 BGATE ICM 9 20 PHASE VREF 10 19 UGATE CHLIM 11 18 BOOT ACLIM 12 17 VDDP VADJ 13 16 LGATE GND 14 15 PGND ISL6253 Absolute Maximum Ratings Thermal Information DCIN, CSIP, DCPRN, ACPRN, CSON to GND . . . . . . -0.3V to +28V CSIP-CSIN, CSOP-CSON . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V CSIP-SGATE, CSIP-BGATE . . . . . . . . . . . . . . . . . . . . . -0.3V to 16V PHASE to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -7V to 28V BOOT to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +35V BOOT-PHASE, VDD-GND, VDDP-PGND . . . . . . . . . . . . -0.3V to 7V ICM, ICOMP, VCOMP . . . . . . . . . . . . . . . . . . . . -0.3V to VDD+0.3V ACSET and DCSET to GND (Note 3) . . . . . . . . -0.8V to VDD+0.3V VDDP, ACLIM, CHLIM, VREF, CELLS. . . . . . . . -0.3V to VDD+0.3V EN, VADJ, PGND to GND . . . . . . . . . . . . . . . . . -0.3V to VDD+0.3V UGATE. . . . . . . . . . . . . . . . . . . . . . . . . PHASE-0.3V to BOOT+0.3V LGATE . . . . . . . . . . . . . . . . . . . . . . . . . . PGND-0.3V to VDDP+0.3V Thermal Resistance θJA (°C/W) θJC (°C/W) QFN Package (Notes 4, 6). . . . . . . . . . 39 9.5 QSOP Package (Note 5) . . . . . . . . . . . 80 NA ESD Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Level 1 Junction Temperature Range. . . . . . . . . . . . . . . . . .-10°C to +150°C Operating Temperature Range . . . . . . . . . . . . . . . .-10°C to +100°C Storage Temperature. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Lead Temperature (soldering, 10s).. . . . . . . . . . . . . . . . . . . . +300°C CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress ratings only and operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. NOTES: 3. When the voltage across ACSET and DCSET is below 0V, the current through ACSET and DCSET should be limited less than 1mA. 4. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with "direct attach" features. See Tech Brief TB379. 5. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details. 6. For θJC, the "case temp" location is the center of the exposed metal pad on the package underside. Electrical Specifications DCIN = CSIP = CSIN = 18V, CSOP = CSON = 12V, ACSET = DCSET = 1.5V, VREF = ACLIM = CHLIM, VADJ = Floating, EN = VDD = 5V, BOOT-PHASE = 5.0V, GND = PGND = 0V, CVDD = 1µF IVDD = 0mA, TA = -10°C to +100°C, TJ ≤ 125°C, unless otherwise noted. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 25 V SUPPLY AND BIAS REGULATOR DCIN Input Voltage Range 7 DCIN Quiescent Current EN = VDD, 7V < DCIN < 25V 1.6 4 mA DCIN Quiescent Current in Shutdown mode EN = 0, 7V < DCIN < 25V 1.3 3 mA Battery Leakage Current (Note 5) DCIN = 0, no load 2 10 µA VDD Output Voltage/Regulation 7V < DCIN < 25 V, 0 < IVDD < 30mA 4.925 5.075 5.225 V VDD Undervoltage Lockout Trip Point Rising 4.2 4.4 4.6 V Hysteresis 100 250 400 mV V O < IVREF < 300µA Reference Output Voltage VREF Battery Charge Voltage Accuracy 2.365 2.390 2.415 CSON = 16.8V, CELLS = VDD, VADJ = Float -0.5 0 0.5 CSON = 12.6V, CELLS = GND, VADJ = Float -0.55 0 0.55 CSON = 8.4V, CELLS = FLOAT, VADJ = Float -0.55 0 0.55 CSON = 17.64V, CELLS = VDD, VADJ = VREF -0.6 0 0.6 CSON = 13.23V, CELLS = GND, VADJ = VREF -0.6 0 0.6 CSON = 8.82V, CELLS = FLOAT, VADJ = VREF -0.6 0 0.6 CSON = 15.96V, CELLS = VDD, VADJ = GND -0.6 0 0.6 CSON = 11.97V, CELLS = GND, VADJ = GND -0.6 0 0.6 CSON = 7.98V, CELLS = FLOAT, VADJ = GND -0.6 0 0.6 1.235 1.26 1.285 V 2 3.4 4.8 µA % TRIP POINTS ACSET Threshold ACSET Input Bias Current Hysteresis ACSET Input Bias Current ACSET > 1.26V 2 3.4 4.8 µA ACSET Input Bias Current ACSET < 1.26V -1 0 1 µA 1.235 1.26 1.285 V DCSET Threshold 3 ISL6253 Electrical Specifications DCIN = CSIP = CSIN = 18V, CSOP = CSON = 12V, ACSET = DCSET = 1.5V, VREF = ACLIM = CHLIM, VADJ = Floating, EN = VDD = 5V, BOOT-PHASE = 5.0V, GND = PGND = 0V, CVDD = 1µF IVDD = 0mA, TA = -10°C to +100°C, TJ ≤ 125°C, unless otherwise noted. (Continued) PARAMETER TEST CONDITIONS DCSET Input Bias Current Hysteresis MIN TYP MAX UNITS 2 3.4 4.8 µA DCSET Input Bias Current DCSET ≥ 1.26V 2 3.4 4.8 µA DCSET Input Bias Current DCSET < 1.26V -1 0 1 µA OSCILLATOR Frequency 240 300 360 kHz CSIP = 18V 1.4 1.55 1.7 V CSIP = 11V 0.8 0.9 1.0 V Maximum Duty Cycle 300kHz 97 99 99.6 % UGATE Pull-up Resistance BOOT-PHASE = 5V, 500mA source current 1.8 3.0 Ω 1.8 Ω PWM Ramp Voltage (peak-peak) SYNCHRONOUS BUCK REGULATOR UGATE Source Current BOOT-PHASE = 5V, BOOT-UGATE = 2.5V 1.0 UGATE Pull-down Resistance BOOT-PHASE = 5V, 500mA sink current 0.9 UGATE Sink Current BOOT-PHASE = 5V, UGATE-PHASE = 2.5V 1.8 LGATE Pull-up Resistance VDDP-PGND = 5V, 500mA source current 1.8 LGATE Source Current VDDP-PGND = 5V, VDDP-LGATE = 2.5V 1.0 LGATE Pull-down Resistance VDDP-PGND = 5V, 500mA sink current 0.9 LGATE Sink Current VDDP-PGND = 5V, LGATE = 2.5V 1.8 A A 3.0 Ω 1.8 Ω A A CHARGING CURRENT SENSING AMPLIFIER Input Common Mode Range 0 Input Offset Voltage Guarantee by design -3 0 18 V 3 mV Input Bias Current at CSOP 0 < CSOP < 18V 10 20 µA Input Bias Current at CSON 0 < CSON < 18V 300 425 µA CSOP to CSON Input Full Scale Sense Voltage CHLIM = 3.3V 123 127 131 mV CHLIM = VREF 96 100 104 mV CHLIM = FLOAT 61 65 69 mV CHLIM = GND 26 30 34 mV CSOP to CSON Input Full Scale Sense Voltage in Trickle CHLIM = 3.3V Charge Mode CHLIM = VREF Trickle Charge Threshold Voltage CHLIM Input Bias Current 6 8.9 12.0 mV 4.0 7.5 11.0 mV CHLIM = FLOAT 2.5 5.6 9.0 mV CHLIM = GND 1.5 3.7 7.0 mV CSON Rising 3.0 3.1 3.2 V/CELL Hysteresis 20 100 180 mV/CELL CHLIM = GND or VREF -25 25 µA 7 25 V -2 2 mV ADAPTER CURRENT SENSING AMPLIFIER Input Common Mode Range Input Offset Voltage Guarantee by design Input Bias Current at CSIP 0 < CSIP < DCIN 325 475 µA Input Bias Current at CSIN 0 < CSIN < DCIN 1 10 µA ADAPTER CURRENT LIMIT THRESHOLD CSIP to CSIN Input Full Scale Sense Voltage 4 ACLIM = VREF 100 103 106 mV ACLIM = Float 75 78 81 mV ACLIM = GND 50 53 56 mV ISL6253 Electrical Specifications DCIN = CSIP = CSIN = 18V, CSOP = CSON = 12V, ACSET = DCSET = 1.5V, VREF = ACLIM = CHLIM, VADJ = Floating, EN = VDD = 5V, BOOT-PHASE = 5.0V, GND = PGND = 0V, CVDD = 1µF IVDD = 0mA, TA = -10°C to +100°C, TJ ≤ 125°C, unless otherwise noted. (Continued) PARAMETER ACLIM Input Bias Current TEST CONDITIONS MIN ACLIM = GND, or VREF -25 CELLS = VDD 20 TYP MAX UNITS 25 µA 40 µA/V 4 V VOLTAGE REGULATION ERROR AMPLIFIER Error Amplifier Trans-conductance from CSON to VCOMP VCOMP Voltage Range 30 0.3 CURRENT REGULATION ERROR AMPLIFIER Charging Current Error Amplifier Trans conductance µA/V 50 Adapter Current Error Amplifier Trans conductance µA/V 50 ICOMP Voltage Range 0.3 4 V 0.5 V VREF + 0.3 V BATTERY CELL SELECTOR CELLS Input Low Voltage CELLS Input Float Voltage CELLS = Float CELLS Input High Current VREF -0.3 VREF VDD0.5 V MOSFET DRIVER BGATE Pull-up Current CSIP-BGATE = 3V 1 1.4 2 mA BGATE Pull-down Current CSIP-BGATE = 5V 3.25 5.0 7 mA 8.0 10 12 V 0 0.1 V -200 0 200 mV CSIP-BGATE Voltage High CSIP-BGATE Voltage Low DCIN-CSON Threshold for CSIP-BGATE Going High DCIN = 12V, CSON Rising DCIN-CSON Threshold for CSIP-BGATE Going Low DCIN = 12V, CSON Falling DCIN-CSON Threshold Hysteresis 0 300 500 mV 250 300 400 mV SGATE Pull-up Current CSIP-SGATE = 3V 1.0 1.4 2.0 mA SGATE Pull-down Current CSIP-SGATE = 2.5V 40 150 350 µA 5 8.5 15 V 0 0.1 V CSIP-SGATE Voltage High CSIP-SGATE Voltage Low CSIP-CSIN Threshold for CSIP-SGATE Going High 3 8.5 15 mV CSIP-CSIN Threshold Hysteresis 1 2 6 mV 0.8 V 13 mA 1 µA 13 mA 1 µA 2.085 V LOGIC INTERFACE EN Low Level Input Voltage EN High Level Input Voltage 2.0 ACPRN Sink Current ACPRN = 0.4V 3 ACPRN Leakage Current ACPRN = 20V -1 DCPRN Sink Current DCPRN = 0.4V 3 DCPRN Leakage Current DCPRN = 20V -1 ICM Output Voltage Iload = 0 to 100µA, CSIP-CSIN = 103mV Thermal Shutdown Temperature Rising Thermal Shutdown Temperature Hysteresis 1.885 V 8 8 1.980 150 °C 20 °C NOTE: 7. This is sum of currents in these pins (CSIP, CSIN, BOOT, UGATE, PHASE, CSOP and CSON) tied together to 18V. EN, ACSET, DCSET, VADJ, CELLS, ACLIM, CHLIM, VDD, DCIN = 0. 5 ISL6253 Typical Operating Performance 0.01 0.1 VDCIN = 20V VDD = 5.075V EN = 0 0 VDD =5.075V IVDD = 0mA 0 -0.1 VDD ACCURACY (%) VDD LOAD REGULATION ACCURACY (%) Circuit of Figure 18, VDCIN = 20V, 4S2P Li-Ion Battery, TA = 25°C, unless otherwise noted. -0.2 -0.3 -0.4 -0.01 -0.02 -0.5 -0.03 -0.6 -0.7 0 5 10 15 20 LOAD CURRENT (mA) 25 -0.04 30 5 5.0 17.0 4.0 16.0 3.0 15.0 2.0 14.0 1.0 13.0 LOAD CURRENT 5A/DIV ADAPTER CURRENT 5A/DIV CHARGE CURRENT 2A/DIV BATTERY VOLTAGE 2V/DIV t: 1ms/DIV, CHLIM = ACLIM = VREF LOAD STEP: 0A TO 4A CHARGE CURRENT = 3A AC ADAPTER CURRENT LIMIT = 5A 12.0 0.0 0 26 50 75 25 FIGURE 2. VDD LINE REGULATION BATTERY VOLTAGE (V) CHARGE CURRENT (A) FIGURE 1. VDD LOAD REGULATION 10 15 20 INPUT VOLTAGE VDCIN (V) 99 TIME (MINUTE) FIGURE 3. BATTERY CHARGE V-I CHARACTERISTICS FIGURE 4. LOAD TRANSIENT RESPONSE INDUCTOR CURRENT 1A/DIV 5 VDCIN 10V/DIV 0 ICM ACCURACY (%) EN=0 BATTERY VOLTAGE 10V/DIV CHARGE CURRENT 1A/DIV -5 -10 -15 t: 10ms/DIV CHARGE CURRENT: 2.6A INPUT VOLTAGE STEP: 18.0V TO 25V LOAD CURRENT: 1A FIGURE 5. LINE TRANSIENT RESPONSE 6 -20 0 1 2 3 AC ADAPTER CURRENT (A) 4 5 FIGURE 6. ICM ACCURACY vs AC ADAPTER CURRENT ISL6253 Typical Operating Performance (Continued) Circuit of Figure 18, VDCIN = 20V, 4S2P Li-Ion Battery, TA = 25°C, unless otherwise noted. EN 5V/DIV SYSTEM BUS VOLTAGE 5V/DIV INDUCTOR CURRENT 2A/DIV BGATE-CSIP 2V/DIV BGATE-CSIP 2V/div SGATE-CSIP SGATE-CSIP 2V/DIV 2V/DIV 2V/div INDUCTOR CURRENT 2A/DIV BATTERY VOLTAGE 2V/DIV t: 0.5ms/DIV t: 0.5ms/DIV FIGURE 7. CHARGE ENABLE AND SHUTDOWN FIGURE 8. AC ADAPTER INSERTION LOAD CURRENT = 2A BGATE-CSIP 2V/DIV INDUCTOR CURRENT 2A/DIV SYSTEM BUS VOLTAGE 5V/DIV BATTERY VOLTAGE 10V/DIV SGATE-CSIP 2V/DIV ICOMP INDUCTOR CURRENT 2A/DIV VCOMP 2V/DIV t: 1ms/DIV t: 5µs/DIV FIGURE 9. AC ADAPTER REMOVAL FIGURE 10. BATTERY INSERTION BATTERY VOLTAGE 2V/DIV VPHASE 10V/DIV VCSON 10V/DIV INDUCTOR CURRENT 1A/DIV INDUCTOR CURRENT 2A/DIV CHARGE CURRENT 1A/DIV t: 20µs/DIV FIGURE 11. BATTERY REMOVAL 7 t: 0.1ms/DIV FIGURE 12. CHARGE MODE TRANSITION FROM TRICKLE MODE TO CONSTANT CURRENT MODE ISL6253 Typical Operating Performance (Continued) Circuit of Figure 18, VDCIN = 20V, 4S2P Li-Ion Battery, TA = 25°C, unless otherwise noted. VDCIN = 20V VDCIN=20V VCSON = 16.8V VCSON=16.8V PHASE 10V/DIV PHASE 10V/DIV INDUCTOR CURRENT 0.5A/DIV LGATE LGATE UGATE UGATE UGATE LGATE 2V/DIV CHARGE CURRENT 0.2A/DIV t: 100ns/DIV 1µs/DIV FIGURE 13. SWITCHING WAVEFORMS AT CONSTANT CHARGE CURRENT MODE FIGURE 14. SWITCHING WAVEFORMS AT TRICKLE CHARGE MODE 1 EFFICIENCY (%) 0.96 VCSON = 12.6V 3 CELLS 0.92 VCSON = 8.4V 2 CELLS VCSON = 16.8V 4 CELLS 0.88 0.84 0.8 0.76 0 0.5 1 1.5 2 2.5 3 3.5 4 CHARGE CURRENT (A) FIGURE 15. EFFICIENCY vs CHARGE CURRENT Functional Pin Descriptions BOOT BGATE Connect BOOT to a 0.1µF ceramic capacitor to the PHASE pin and connect to the cathode of the bootstrap Schottky diode. UGATE is the high side MOSFET gate drive output. BGATE power source select output. This pin drives an external P-channel MOSFET used to switch the battery as the system power source. When the voltage at the CSON pin is higher than the AC adapter output voltage at DCIN, BGATE is driven to low and selects the battery as the power source. SGATE LGATE SGATE is the AC adapter power source select output. The SGATE pin drives an external P-MOSFET used to switch to AC adapter as the system power source. LGATE is the low side MOSFET gate drive output; swing between PGND and VDDP. UGATE 8 ISL6253 PHASE PGND The Phase connection pin connects to the high side MOSFET source, output inductor, and low side MOSFET drain. PGND is the power ground. Connect PGND to the source of the low side MOSFET for the low side MOSFET gate driver. CSOP/CSON VDD is an internal LDO output to supply the IC analog circuit. Connect a 1µF ceramic capacitor to ground. CSOP/CSON are the battery charging current sensing positive/negative inputs. The differential voltage across CSOP and CSON is used to sense the battery charging current, and is compared with the charging current limit threshold to regulate the charging current. The CSON pin is also used as the battery feedback voltage to perform voltage regulation. CSIP/CSIN CSIP/CSIN are the AC adapter current sensing positive/ negative inputs. The differential voltage across CSIP and CSIN is used to sense the AC adapter current, and is compared with the AC adapter current limit to regulate the AC adapter current. VDD VDDP VDDP is the supply voltage for the MOSFET gate driver. Connect a 4.7Ω resistor to VDD and a 1µF ceramic capacitor to power ground. ICOMP ICOMP is a current loop error amplifier output. Connect a ceramic capacitor to ground. VCOMP VCOMP is a voltage loop amplifier output. Connect a ceramic capacitor in series with a resistor to ground. CELLS GND This pin is used to select the battery voltage. CELLS = VDD for a 4S battery, CELLS = GND for a 3S battery pack, and CELLS = Float for a 2S battery pack. GND is an analog ground. DCIN The DCIN pin is the input of the internal 5V LDO. Connect it to the AC adapter output. Connect DCIN to a 0.1µF ceramic capacitor. VADJ ACSET is an AC adapter detection input. Connect a resistor divider to an AC adapter. VADJ adjusts battery regulation voltage. VADJ = VREF for 4.2V +5%/cell; VADJ = Floating for 4.2V/cell; VADJ = GND for 4.2V -5%/cell. Connect to a resistor divider from VREF to program the desired battery cell voltage between 4.2V -5% and 4.2V +5%. ACPRN CHLIM ACPRN is an AC adapter present open drain output. ACPRN is active low when ACSET is higher than 1.26V; and active high when ACSET is lower than 1.26V. CHLIM is the battery charge current limit set pin. CHLIM = VREF for 100mV, CHLIM = Floating for 65mV; CHLIM = GND for 30mV. Connect 3.3V for 127mV. Connect a resistor divider to program the charge current limit threshold between 30mV and 127mV. ACSET DCSET DCSET is a lower voltage adapter detection input (like aircraft power 15V). This allows power to the system, but power is not used to charge the battery. DCPRN DCPRN is a DC adapter present open drain output. DCPRN is active low when DCSET is higher than 1.26V; and active high when DCSET is lower than 1.26V. EN EN is the Charge Enable input. Connecting EN to high enables the charge control function, connecting EN to low disables charging functions. ICM ICM is the adapter current output. The output of this pin produces a voltage proportional to the adapter current. 9 ACLIM ACLIM is the adapter current limit set pin. ACLIM = VREF for 103mV, ACLIM = Floating for 78mV, and ACLIM = GND for 53mV. Connect a resistor divider from VREF to program the adapter current limit threshold between 53mV and 103mV. VREF VREF is a reference output pin. Do not connect a decoupling capacitor. ISL6253 DCIN SGATE CSIP CSIN DCSET DCPRN + VDDP -- + 1.26V CA1 ICM DCIN + CSON ACSET + ACPRN - BIAS Bias REGULATOR Regulator 1.26V BGATE - VDD gm3 ADAPTER CURRENT LIMIT SET ACLIM BOOT + MIN. CURRENT BUFFER ICOMP 2.1V UGATE MIN VOLTAGE BUFFER + gm1 - PHASE VDDP - + VCOMP 0.25V LGATE PWM CA2 + VOLTAGE VADJ PGND SELECTOR 3.1V/CELL gm2 UV + - + -- CELLS VCA2 Charge CHARGE Current CURRENT Set SET Reference REFERENCE GND CHLIM FIGURE 16. BLOCK DIAGRAM 10 CSON + CSOP CA2 VDD VREF - EN ISL6253 INPUT: 7V TO 25V Q3 C9 0.1µF D3 R8 130K 1% CSON SGATE DCIN R9 10.2K 1% ACSET CSIP CSIP ISL6253 ISL6253 C3 0.1µF R2 20mΩ VDDP C12 1µF R3: 18Ω VDD R5 100K DIGITAL INPUT C10 1µF OUTPUT BOOT BOOT ACPRN UGATE UGATE CHLIM PHASE PHASE EN LGATE LGATE ICM 5A INPUT C13 CURRENT LIMIT 0.1 0.1µF C7 6.8nF ACLIM VCOMP C6 10nF R10, R11, R12 10K FLOATING 4.2V/CELL PGND PGND CSOP CSOP C4 1µF VREF ICOMP SCL SDL A/D INPUT GND L 15µH R1 25mΩ 25m R4 2.2Ω BAT+ CSON CSON 4 CELLS CELLS CELLS VDD C11 22µF BATTERY PACK GND GND VADJ DCSET DCSET FIGURE 17. TYPICAL APPLICATION CIRCUIT 1 11 D1 OPTIONAL Q2 A/D INPUT AVDD/VREF Q1 C5 0.1µF R13: 100Ω R6 10K C2 10µF C1:10µF VDDP D2 D/A OUTPUT HOST LOAD CSIN CSIN R7 4.7 4.7Ω VCC SYSTEM SCL SDL TEMP BAT- ISL6253 AC ADAPTER Q5 R13 100K 1% R8 130K 1% R14 10.5K 1% R9 10.2K 1% C9 0.1µF CSON VDD DCIN Q3 SGATE SGATE ACSET CSIP CSIP DCSET C8: 1µF VCC R5, R14 100K R7 4.7Ω C10: 1µF ISL6253 ISL6253 VDDP CSIN CSIN C3 0.1µF R2 20mΩ R3: 18Ω VDD ACPRN DIGITAL INPUT DCPRN CHLIM EN OUTPUT R13: 100Ω ICM A/D INPUT C12 0.1µF 5A INPUT CURRENT LIMIT HOST ACLIM VREF C7 6.8nF ICOMP R10,R11 R12:10k AVDD/VREF VCOMP R6 10k C6 10nF C2 10µF BGATE BGATE VDDP DIGITAL INPUT D/A OUTPUT SYSTEM LOAD C1:10µF BOOT BOOT Q4 D2 UGATE PHASE Q1 C5 0.1µF Q2 D1 Optional LGATE L 15µH PGND CSOP C4 1µF R4 2.2Ω R1 25mΩ BAT+ CSON CELLS 3 CELLS GND VADJ C11 22µF BATTERY PACK FLOAT 4.2V/CELL SCL SDL A/D INPUT GND SCL SDL TEMP BAT- FIGURE 18. ISL6253 CONTROLLED TYPICAL APPLICATION 2 12 ISL6253 Theory of Operation Introduction The ISL6253 includes all of the functions necessary to charge 2 to 4 cell Li-Ion and Li-polymer batteries. A high efficiency synchronous buck converter is used to control the charging voltage and charging current up to 10 amps. The ISL6253 has input current limiting and analog inputs for setting the charge current and charge voltage; CHLIM inputs are used to control charge current and VADJ inputs are used to control charge voltage. The ISL6253 safely conditions over-discharged battery cells with a percentage of full charge current until the battery voltage exceeds 3.1V × number of series connected cells. When the battery voltage exceeds 3.1V × number of series connected cells, the ISL6253 charges the battery with constant charge current, set by CHLIM input, until the battery voltage rises to a programmed charge voltage set by VADJ input; then the charger begins to operate at constant voltage charge mode. The charger drives an adapter isolation p-channel MOSFET to efficiently switch in the adapter supply. ISL6253 is a complete power source selection controller for single battery systems and also aircraft power applications. ISL6253 drives a battery selector p-channel MOSFET to efficiently select between a single battery and the adapter. It controls the battery discharging MOSFET and switches to the battery when the AC adapter is removed, or, switches to the AC adapter when the AC adapter is inserted for a single battery system. The EN input allows shutdown of the charger from a micro-controller. The amount of adapter current is reported on the ICM output. Figure 16 shows the IC functional block diagram. The synchronous buck converter uses external N-channel MOSFETs to convert the input voltage to the required charging current and charging voltage. Figure 17 shows the ISL6253 typical application circuit 1 without power source selection function. The typical application circuit 2 shown in Figure 18 has automatic power source selection functionality and supports aircraft power applications. The voltage at CHLIM and the value of R1 sets the charging current. The DC-DC converter generates the control signals to drive two external N-channel MOSFETs to regulate the voltage and current set by the ACLIM, CHLIM, VADJ and CELLS inputs. The ISL6253 features a voltage regulation loop (VCOMP) and two current regulation loops (ICOMP). The VCOMP voltage regulation loop monitors CSON to ensure that its voltage never exceeds the voltage set by VADJ. The ICOMP current regulation loops regulate the battery charging current delivered to the battery to ensure that it never exceeds the charging current limit set by CHLIM; and the ICOMP current regulation loops regulate the input current drawn from the AC adapter to ensure that it never exceeds the input current 13 limit set by ACLIM, and to prevent a system crash and AC adapter overload. PWM Control The ISL6253 employs a fixed frequency PWM current mode control architecture with a feed forward function. The feedforward function maintains a constant modulator gain of 11 to achieve fast line regulation as the buck input voltage changes. When the battery charge voltage approaches the input voltage, the DC-DC converter operates in dropout mode, where there is a timer to prevent the frequency from dropping into the audible frequency range. It can achieve a maximum duty cycle of up to 99.6%. An adaptive gate drive scheme is used to control the dead time between two switches. The dead time control circuit monitors the LGATE output and prevents the upper side MOSFET from turning on until LGATE is fully off, preventing cross-conduction and shoot-through. In order for the dead time circuit to work properly, there must be a low resistance, low inductance path from the LGATE driver to MOSFET gate, and from the source of MOSFET to PGND. The external Schottky diode is between the VDDP pin and BOOT pin to keep the bootstrap capacitor charged. The PWM controller is disabled when EN = GND, but the rest of the circuitry, including the AC or DC adapter detecting circuit and AC adapter current monitoring circuits, is still alive. Setting the Battery Regulation Voltage The ISL6253 uses a high-accuracy trimmed band-gap voltage reference to regulate the battery charging voltage. The VADJ input adjusts the charger output voltage, and the VADJ control voltage can vary from 0 to VREF (2.39V), providing a 10% adjustment range (from 4.2V -5% to 4.2V +5%) on CSON regulation voltage. An overall voltage accuracy of better than 0.5% is achieved. The per-cell battery termination voltage is a function of the battery chemistry. Consult the battery manufacturers to determine this voltage. Float VADJ to set the battery voltage VCSON = 4.2V × number of the cells, • Connect VADJ to VREF to set 4.41V × number of cells, • Connect VADJ to ground to set 3.99V × number of cells. Note that other battery charge voltages can be set by connecting a resistor divider from VREF to ground. The resistor divider should be sized to draw no more than 100µA from VREF; or connect a low impedance voltage source like the D/A converter in the micro-controller. The programmed battery voltage per cell can be determined by the following equation: V CELL = 0.175V VADJ + 3.99V (EQ. 1) ISL6253 Connect CELLS as shown in Table 1 to charge 2, 3, or 4 Li+ cells. When charging other cell chemistries, use CELLS to select an output voltage range for the charger. The internal error amplifier gm1 maintains voltage regulation. The voltage error amplifier is compensated at VCOMP. The component values shown in Figure 18 provide suitable performance for most applications. Individual compensation of the voltage regulation and current-regulation loops allows for optimal compensation. the input current by reducing the charging current, when the input current exceeds the input current−limit set point. System current normally fluctuates as portions of the system are powered up or down. Without input current regulation, the source must be able to supply the maximum system current and the maximum charger input current simultaneously. By using the input current limiter, the current capability of the AC adapter can be lowered, reducing system cost. TABLE 1. CELL NUMBER PROGRAMMING The ISL6253 limits the battery charge current when the input current-limit threshold is exceeded, ensuring the battery charger does not load down the AC adapter voltage. An internal amplifier gm3 compares the voltage between CSIP and CSIN to the input current limit threshold voltage set by ACLIM. Connect ACLIM to REF, Float and GND for the fullscale input current limit threshold voltage of 103mV, 78mV, and 53mV, respectively, or use a resistor divider from VREF to ground to set the input current limit as the following equation: CELLS CELL NUMBER VCC 4 GND 3 Float 2 Setting the Battery Charge Current Limit The CHLIM input sets the maximum charging current. The current set by the current sense-resistor connects between CSOP and CSON. There are three default battery charge current-sense threshold voltages: 127mV for CHLIM = 3.3V, 100mV for CHLIM = VREF, 65mV for Float, and 30mV for ground. The full-scale differential voltage between CSOP and CSON is 100mV for CHLIM = VREF, so the maximum charging current is 4.0A for a 25mΩ sensing resistor. Other battery charge current-sense threshold values can be set by connecting a resistor divider from VREF or VDD to ground, or by connecting a low impedance voltage source like a D/A converter in the microcontroller. The charge current limit threshold is given by: 1 0.07 I CHG = ------- ----------------- V CHLIM + 0.03 R 1 VREF (EQ. 2) If the battery voltage is less than 3.0V/cell and the battery charging voltage is a percentage of the charging current in constant current charge mode, the trickle charge current limit threshold is given by: 1 I TR ,CHG = ------- ( 0.00157 × V CHLIM + 0.0037 R1 (EQ. 3) 1 0.05 I INPUT = ------- ----------------- V ACLIM + 0.053 R 2 VREF (EQ. 4) When choosing the current sense resistor, note that the voltage drop across this resistor causes further power dissipation, reducing efficiency. The AC adapter current sense accuracy is very important. Use a 1% tolerance current-sense resistor. The highest accuracy of ± 3% is achieved with 103mV current-sense threshold voltage for ACLIM = VREF, but it has the highest power dissipation. For example, it has 400mW power dissipation for rated 4A AC adapter, and a 1W sensing resistor may have to be used. ± 4% and ± 6% accuracy can be achieved with 78mV and 53mV current-sense threshold voltage for ACLIM = Floating and ACLIM = GND, respectively. A low pass filter is recommended to eliminate the switching noise. Connect the resistor to the CSIN pin instead of the CSIP pin because the CSIN pin has lower bias current and less influence on the current-sense accuracy. AC Adapter Detection When choosing the current sensing resistor, note that the voltage drop across the sensing resistor causes further power dissipation, reducing efficiency. However, adjusting CHLIM voltage to reduce the voltage across the current sense resistor R1 will degrade accuracy due to the smaller signal to the input of the current sense amplifier. There is a trade-off between accuracy and power dissipation. A low pass filter is recommended to eliminate switching noise. Connect the resistor to the CSOP pin instead of the CSON pin, as the CSOP pin has lower bias current and less influence on current-sense accuracy. Connect the AC adapter voltage through a resistor divider to ACSET to detect when AC power is available, as shown in Figure 17. ACPRN is an open-drain output and is high impedance when ACSET is less than Vth,rise and active low impedance when ACSET is above Vth,fall . Vth,rise and Vth,fall are given by: Setting the Input Current Limit Where Ihys is the ACSET input bias current hysteresis and VACSET = 1.235V (min), 1.26V (typ.) and 1.285V (max.). The hysteresis is Ihys R8, where Ihys = 2µA (min.), 3.4µA (typ.) and 4.8µA (max.) The total input current from an AC adapter, or other DC source, is a function of the system supply current and the battery-charging current. The input current regulator limits 14 R V th, rise = ------8- + 1 • V ACSET R9 (EQ. 5) R V th, fall = ------8- + 1 • V ACSET – I hys R 8 R9 ISL6253 DC Adapter Detection Connect the DC adapter voltage like aircraft power through a resistor divider to DCSET to detect when DC power is available, as shown in Figure 18. DCPRN is an open-drain output and is high impedance when DCSET is less than Vth,rise, and active low impedance when DCSET is above Vth,fall. Vth,rise and Vth,fall are given by: R 13 V th, rise = --------- + 1 • V DCSET R 14 (EQ. 6) R 13 V th, fall = --------- + 1 • V DCSET – I hys R 13 R 14 Short Circuit Protection and 0V Battery Charging Where Ihys is the DCSET input bias current hysteresis and VACSET = 1.235V (min), 1.26V (typ.) and 1.285V (max.). The hysteresis is IhysR13, where Ihys = 2µA (min.), 3.4µA (typ.) and 4.8µA (max.) Current Measurement Use ICM to monitor the input current being sensed across CSIP and CSIN. The output voltage range is 0 to 2.5V. The voltage of ICM is proportional to the voltage drop across CSIP and CSIN, and is given by the following equation: ICM = 19.22 • I INPUT • R 2 (EQ. 7) where IINPUT is the DC current drawn from the AC adapter. ICM has ±5% accuracy. Connect a low pass filter to ICM to bypass the switching frequency noise. LDO Regulator VDD provides a 5.0V supply voltage from the internal LDO regulator from DCIN and can deliver up to 30mA of current. This 30mA current is only used to supply the analog and logic circuits for the IC and power the gate drivers. The MOSFET drivers are powered by VDDP, and VDDP connects to VDD through an external low pass filter. Bypass VDDP and VDD with a 1µF capacitor. Supply Isolation If the voltage across the adapter sense resistor R2 is typically greater than 8.5mV, the p-channel MOSFET controlled by SGATE is turned on reducing the power dissipation. If the voltage across the adapter sense resistor R2 is less than 2mV, SGATE turns off the p-channel MOSFET isolating the adapter from the system bus. Battery Power Source Selection and Aircraft Power Application The battery voltage is monitored by CSON. If the battery voltage measured on CSON is less than the adapter voltage measured on DCIN, then the p-channel MOSFET controlled by BGATE turns off. If it is greater, then BGATE turns on the battery discharge p-channel MOSFET to minimize the power loss. In the meantime, it also disables charging function and turns off the AC adapter isolation p-channel MOSFET controlled by SGATE. If designing for airplane power, 15 DCSET is tied to a resistor divider sensing the adapter voltage. When a user is plugged into the 15V airplane supply and their battery is lower than 15V, the MOSFET driven by BGATE (see Figure 18) is turned off and keeps the battery from supplying the system bus. The comparator looking at CSON and DCIN has 300mV of hysteresis to avoid chattering. For aircraft power applications the ISL6253 is only able to support 2S and 3S battery packs when disabling the charging function based on DCPRN and ACPRN signals. For 4S battery packs, DCSET = 0 and the DCPRN signal is not available to support aircraft power applications. Since the battery charger will regulate the charge current to be trickle charge current, as long as the battery voltage is below 3.0V/cell, it automatically has short circuit protection and is able to provide the trickle charge current and "wakeup" an extremely discharged battery. Over Temperature Protection If the die temp exceeds 150°C, it stops charging. Once the die temp drops below 130°C, charging will start up again. Application Information The following battery charger design refers to the typical application circuit in Figure 17, where a typical battery configuration of 4S2P is used. This section describes how to select the external components including the inductor, input and output capacitors, switching MOSFETs, and current sensing resistors. Inductor Selection The inductor selection has trade-offs between cost, size and efficiency. For example, the lower the inductance, the smaller the size, but ripple current is higher. This also results in higher ac losses in the magnetic core and the windings, which decrease the system efficiency. On the other hand, the higher inductance results in lower ripple current and smaller output filter capacitors, but it has higher DCR (dc resistance of the inductor) loss, and has slower transient response. So, the practical inductor design is based on the inductor ripple current being ±(15-20)% of the maximum operating dc current at maximum input voltage. The required inductance can be calculated from: V BAT V IN ,MAX – V BAT L = --------------------------------------------- ---------------------------∆I L V IN ,MAX f s (EQ. 8) where VIN,MAX, VBAT, and fs are the maximum input voltage, battery voltage and switching frequency, respectively. The inductor ripple current ∆IL is found from: ∆I L = 30% ⋅ I BAT ,MAX (EQ. 9) where the maximum peak-to-peak ripple current is 30% of the maximum charge current used. ISL6253 For VIN,MAX = 20V, VBAT = 16.8V, IBAT,MAX = 4A, and fs = 300kHz, the calculated inductance is 12.8µH. Choosing the closest standard value gives L = 15µH. Ferrite cores are often the best choice since they are optimized at 300kHz to 600kHz operation with low core loss. The core must be large enough not to saturate at the peak inductor current IPeak: 1 I Peak = I BAT ,MAX + --- ∆I L 2 (EQ. 10) Output Capacitor Selection The output capacitor in parallel with the battery is used to absorb the high frequency switching ripple current and smooth the output voltage. The RMS value of the output ripple current Irms is given by: V IN ,MAX I RMS = ----------------------- D ( 1 – D ) 12 L f s (EQ. 11) where the duty cycle D is the ratio of the output voltage (battery voltage) over the input voltage for continuous conduction mode, which is typical operation for a battery charger. During the battery charge period, the output voltage varies from its initial battery voltage to the rated battery voltage; therefore, the duty cycle change can be in the range of between 0.375 and 0.63 for the minimum battery voltage of 7.5V (2.5V/Cell) and the maximum battery voltage of 12.8V. The maximum RMS value of the output ripple current occurs at the duty cycle of 0.5 and is expressed as: V IN ,MAX I RMS = ----------------------4 12 Lf s (EQ. 12) For VIN,MAX = 20V, L = 15µH, and fs = 300kHz, the maximum RMS current is 0.32A. A typical 10µF or 22µF ceramic capacitor is a good choice to absorb this current, and also has very small size. The tantalum capacitor has a known failure mechanism when subjected to high surge current. EMI considerations usually make it desirable to minimize ripple current in the battery leads. Beads may be added in series with the battery pack to increase the battery impedance at 300kHz switching frequency. Switching ripple current splits itself between the battery and the output capacitor, depending on the ESR of the output capacitor and the battery impedance. If the ESR of the output capacitor is 20mΩ and the battery impedance is raised to 2Ω with a bead, then only 1% of the ripple current will flow in the battery. MOSFET Selection The notebook battery charger synchronous buck converter has input voltage from the AC adapter output. The maximum AC adapter output voltage does not exceed 25V; therefore, a 30V logic MOSFET should be used. The high side MOSFET must be able to dissipate the conduction losses plus the switching losses. For the battery 16 charger application, the input voltage of the synchronous buck converter is equal to the AC adapter output voltage, which is relatively constant. The maximum efficiency is achieved by selecting a high side MOSFET that has the conduction losses equal to the switching losses. Ensure that the ISL6253 LGATE gate driver can supply sufficient gate current to prevent it from conduction, which is due to the injected current into the drain-to-source parasitic capacitor (Miller capacitor Cgd), and caused by the voltage rising rate at the phase node at the moment of the high-side MOSFET turning on; otherwise, cross-conduction problems may occur. Reasonably slowing the turn-on speed of the highside MOSFET, by connecting a resistor between the BOOT pin and gate drive supply source, and the high sink current capability of the low-side MOSFET gate driver, helps reduce the possibility of cross-conduction. For the high-side MOSFET, the worst-case conduction losses occur at the minimum input voltage: V OUT 2 P Q1 ,Conduction = ---------------- I BAT R DSON V IN (EQ. 13) The optimum efficiency occurs when the switching losses equal the conduction losses. However, it is difficult to calculate the switching losses in the high-side MOSFET since it must allow for difficult-to-quantify factors that influence the turn-on and turn-off times. These factors include: the MOSFET internal gate resistance, gate charge, threshold voltage, stray inductance, and pull-up and pulldown resistance of the gate driver. The following switching loss calculation provides a rough estimate: (EQ. 14) Q gd Q gd 1 1 PQ1 ,Switching = --- V IN I LV f s ------------------------+ --- V IN I LP f s ---------------- + Q rr VIN f s I g ,source 2 I g , sin k 2 where Qgd is drain-to-gate charge; Qrr is total reverse recovery charge of the body-diode in low side MOSFET; ILV is inductor valley current; ILP is Inductor peak current; and Ig,sink and Ig,source are the peak gate-drive source/sink current of Q1, respectively. Achievement of low switching losses requires low drain-togate charge, Qgd. Generally, the lower the drain-to-gate charge, the higher the on-resistance; therefore, there is a trade-off between the on-resistance and drain-to-gate charge. Good MOSFET selection is based on the Figure of Merit (FOM), which is the product of the total gate charge and on-resistance. Usually, the smaller the value of FOM, the higher the efficiency for the same application. For the low-side MOSFET, the worst-case power dissipation occurs at minimum battery voltage and maximum input voltage: V OUT 2 P Q2 = 1 – --------------- I R V IN BAT DSON (EQ. 15) ISL6253 Choose a low-side MOSFET that has the lowest possible on-resistance, has a moderate-sized package like SO-8 and is reasonably priced. The switching losses are not an issue for the low side MOSFET because it operates at zerovoltage-switching. Choose a Schottky diode in parallel with low-side MOSFET Q2 with a forward voltage drop low enough to prevent the low-side MOSFET Q2 body-diode from turning on during the dead time. This also reduces the power loss in the high-side MOSFET associated with the reverse recovery of the lowside MOSFET Q2 body diode. As a general rule, select a diode with a DC current rating equal to one-third of the load current. One option is to choose a combined MOSFET and Schottky diode in a single package. The integrated packages may work better in practice because there is less stray inductance due to a short connection. This Schottky diode is optional and may be removed if efficiency loss can be tolerated. In addition, ensure that the required total gate drive current for the selected MOSFETs is less than 26mA. The total gate charge for the high-side and low-side MOSFETs is limited by the following equation: I GATE Q GATE ≤ ----------------fs (EQ. 16) where IGATE is the total gate drive current and should be less than 26mA. Substituting IGATE = 26mA and fs = 300kHz into the above equation yields a total gate charge which should be less than 86nC; therefore, the ISL6253 easily drives the battery charge current up to 10A. Input Capacitor Selection The input capacitor absorbs the ripple current from the synchronous buck converter, which is given by: V OUT ( V IN – V OUT ) I rms = I BAT ---------------------------------------------------V IN (EQ. 17) This RMS ripple current must be smaller than the rated RMS current in the capacitor data sheet. Non-tantalum chemistries (ceramic, aluminum, or OSCON) are preferred due to their resistance to power-up surge currents when the AC adapter is plugged into the battery charger. For Notebook battery charger applications, a ceramic capacitor or a polymer capacitor from Sanyo is recommended due to its small size and reasonable cost. Table 2 shows the component lists for the typical application circuit in Figure 18. TABLE 2. COMPONENT LIST PARTS C1, C2 PART NUMBERS AND MANUFACTURER 10µF/25V ceramic capacitor, TDK, C4532X7R1E106M C3, C5, C9, C12 0.1µF/50V ceramic capacitor C4, C8, C10 1µF/10V ceramic capacitor, Taiyo Yuden LMK212BJ105MG C6 10nF ceramic capacitor C7 6.8nF ceramic capacitor C11 10µF or 22µF/25V/10mΩ ceramic capacitor TDK, C5750X7R1E226M D1 30V/3A Schottky Diode, EC31QS03L, Nihon (optional) D2, D3 L 100mA/30V Schottky Diode, Central Semiconductor 15µH/4.5A/20mΩ, Sumida, CDRH127-150 Q1 30V/14mΩ, IRF7811AV, International Rectifier Q2 30V/30mΩ, FDS6612A, Fairchild Q3 -30V/9.5mΩ, Si4413DY, Siliconix R1 25mΩ, ±1%, LRC-LR2010-01-R025-F, IRC R2 20mΩ, ±1%, LRC-LR2010-01-R020-F, IRC R3 18Ω, ±5%, (0805) R4 2.2Ω, ±5%, (0805) R5 100kΩ, ±5%, (0805) R6 10k, ±5%, (0805) R7 4.7Ω, ±5%, (0805) R8 130kΩ, ±1%, (0805) R9 10.2kΩ, ±1%, (0805) R10, R11, R12 10kΩ, ±5%, (0805) R13 100Ω, ±5%, (0805) R14 100kΩ, ±5%, (0805) Loop Compensation Design ISL6253 uses constant frequency current mode control architecture to achieve fast loop transient response. Accurate current sensing resistors in series with the output inductor is used to regulate the charge current, and the sensed current signal is injected into the voltage loop to achieve current mode control to simplify the loop compensation design. The inductor is not considered as a state variable for current mode control, and the system becomes a single order system. It is much easier to design a type II compensator to stabilize the voltage loop than voltage mode control. Figure 19 shows the small signal model of the synchronous buck regulator. 17 ISL6253 PWM Comparator Gain Fm The PWM comparator gain Fm for peak current mode control is given by: 1 dˆ F m = ----------------- = ----------------V PWM vˆ comp (EQ. 18) where VPWM is the peak-peak voltage of the PWM ramp signal. Current Sampling Transfer Function He(S) In current loop, the current signal is sampled every switching cycle. It has the following transfer function: 2 (EQ. 19) S S H e ( S ) = ------- + --------------- + 1 2 ω Q n n ωn If Ti(S)>>1, then the above equation can be simplified as follows: S 1 + -----------V FB R o + R L ω esr A v ( S ) 1 L v ( S ) = ----------- --------------------- ---------------------- ----------------, ω p ≈ --------------S He ( S ) V o R TV Ro Co 1 + ------ωp Where RTV is the trans-resistance due to the current information fed into the voltage loop. From the above equation, it is shown that the system is a single order system, which has a single pole located at ω p before the half switching frequency. Therefore, a simple type II compensator can be easily used to stabilize the system. Figure 20 shows the type II compensator, and its transfer function is expressed as follows: 2 where Qn and ωn are given by Q n = – ---, ω n = πf s , π respectively. ^ iin Power Stage Transfer Functions v^in + Transfer function F1(S) from control to output voltage is: S 1 + -----------ω esr vˆ o F 1 ( S ) = ------ = V in --------------------------------------2 dˆ S S ------- + --------------- + 1 2 ω Q o p ωo ^ 1:D ILd ^ iL ^ Vo L ^ Vind Rc + RT Ro Co (EQ. 20) Ti(S) ^ d K Fm C 1 1 Where ω esr = --------------, Q ≈ R o ------o-, ω o = --------------L Rc Co p LC o Transfer function F2(S) from control to inductor current is, S 1 + -----(EQ. 21) ˆi ωz V in 1 o -------------------- --------------------------------------- where ω z ≈ --------------F 2 ( S ) = ---- = Ro Co dˆ R o + R L S 2 S ------- + --------------- + 1 2 ω Q o p ωo Current loop gain Ti(S) is expressed as the following equation: T i ( S ) = R T F m F 2 ( S )H e ( S ) (EQ. 25) He(S) + Tv(S) V^comp -Av(S) FIGURE 19. SMALL SIGNAL MODEL OF SYNCHRONOUS BUCK REGULATOR Vo (EQ. 22) VFB where RT is the trans-resistance in current loop. RT is usually equal to the product of the current sensing resistance of the current amplifier. For ISL6253, RT = 24R1. The voltage gain with open current loop is: VREF + gm VCOMP R1 C2 C1 (EQ. 23) T v ( S ) = KF m F 1 ( S )A v ( S ) V FB where K = ----------- , VFB is the feedback voltage of the voltage Vo FIGURE 20. TYPE II COMPENSATOR error amplifier. The Voltage loop gain with current loop closed is given by: Tv ( S ) L v ( S ) = ----------------------1 + Ti ( S ) (EQ. 24) 18 ISL6253 Figure 20 shows the type II compensator and its transfer function is expressed as follows: S 1 + ---------ω cz gm vˆ comp A v ( S ) = ----------------- = --------------------- -----------------------------C1 + C2 S vˆ FB S 1 + ---------- ω (EQ. 26) cp PCB Layout Considerations Power and Signal Layer Placement on the PCB As a general rule, power layers should be close together, either on the top or bottom of the board, with signal layers on the opposite side of the board. For example, layer arrangement on a 4 layer board is shown below: 1 1 2 where ω cz = --------------- , ω cp = ---------------------- C +C Layer 1: Small signal external components R1 C1 C2 Layer 2: Signal Ground Compensator design goal: Layer 3: Power Ground • High DC gain Layer 4: Bottom Layer: Power MOSFET, Inductors and other Power traces R1 C1 1 1 • Loop bandwidth fc: --- – ------ f s 5 30 Separate the power voltage and current flowing path from the control and logic level signal path. The controller IC will stay on the signal layer, which is isolated by the signal ground to the power signal traces. • Gain margin: >10dB • Phase margin: 40° The compensator design procedure is as follows: 1 1. Put compensator zero at ω cz = ( 1 – 3 ) -------------R C Component Placement o o 2. Put one compensator pole at zero frequency to achieve high DC gain, and put another compensator pole at either esr zero frequency or half switching frequency, whichever is lower. The loop gain Tv(S) at cross over frequency of fc has unity gain. Therefore, the compensator resistance R1 is determined by: 2πf c V o C o R T R 1 = ----------------------------------g m V FB (EQ. 27) where gm is the trans-conductance of the voltage error amplifier. Compensator capacitor C1 is then given by: C1 1 C 1 = -----------------, C 2 = ----------------------------------------2πR 1 C 1 f esr – 1 R 1 ω cz (EQ. 28) Example: Vin = 20V, Vo = 16.8V, Io = 4A, fs = 300kHz, Co = 22µF/10mΩ, L = 15µH, gm = 250µs, RT = 0.15Ω (Rcs = 25mΩ, Ac = 6), VFB = 2.1V, VPWM = VIN/11, fc = 15kHz, then compensator resistance R1 = 10kΩ. Put the compensator zero at 1.7kHz, and put the compensator pole at esr zero which is 725kHz. The compensator capacitors are: C1 = 10nF, C2 = 22pF Such small C2 may not be necessary since it does not affect the phase and gain at such high frequency. 19 The power MOSFET should be close to the IC so that the gate drive signal, the LGATE, UGATE, PHASE, and BOOT traces can be short. Place the components in such a way that the area under the IC has fewer noise traces with high dv/dt and di/dt, such as gate signals and phase node signals. SIGNAL GROUND AND POWER GROUND CONNECTION At minimum, a reasonably large area of copper, which will shield other noise couplings through the IC, should be used as signal ground beneath the IC. The best tie-point between the signal ground and the power ground is at the negative side of the output capacitor on each side, where there is little noise; a noisy trace beneath the IC is not recommended. GND AND VDD PIN At least one high quality ceramic decoupling cap should be used to cross the GND and VDD pins. The decoupling cap can be put close to the IC. LGATE PIN This is the gate drive signal for the bottom MOSFET of the buck converter. The signal going through this trace has both high dv/dt and high di/dt, and the peak charging and discharging current is very high. These two traces should be short, wide, and away from other traces. There should be no other traces in parallel with these traces on any layer. PGND PIN The PGND pin should be laid out to the negative side of the relevant output cap with separate traces. The negative side of the output capacitor must be close to the source node of the bottom MOSFET. ISL6253 PHASE PIN DCIN PIN This trace should be short, and positioned away from other weak signal traces. This node has a very high dv/dt with a voltage swing from the input voltage to ground. No trace should be in parallel with it. This trace is also the return path for UGATE. Connect this pin to the high-side MOSFET source. This pin connects to AC adapter output voltage, and should be less noise sensitive. UGATE PIN This pin has a square shape waveform with high dv/dt. It provides the gate drive current to charge and discharges the top MOSFET with high di/dt. This trace should be wide, short, and away from other traces similar to the LGATE. BOOT PIN The BOOT pins di/dt is as high as the UGATE; therefore, this trace should be as short as possible. CSOP, CSON PINS The current sense resistor connects to the CSON and the CSOP pins through a low pass filter. The CSON pin is also used as the battery voltage feedback. The traces should be away from the high dv/dt and di/di pins like the PHASE and BOOT pins. In general, the current sense resistor should be close to the IC. Other layout arrangements should be adjusted accordingly. EN PIN This pin stays high at enable mode and low at idle mode, and is relatively robust. Enable signals should refer to the signal ground. 20 Copper Size for the Phase Node The capacitance of PHASE should be kept very low to minimize ringing. It would be best to limit the size of the PHASE node copper in strict accordance with the current and thermal management of the application. Identify the Power and Signal Ground The input and output capacitors of the converters, and the source terminal of the bottom switching MOSFET PGND should connect to the power ground. The other components should connect to signal ground. Signal and power ground are tied together at one point. Clamping Capacitor for Switching MOSFET It is recommended that ceramic caps be used closely connected to the drain of the high-side MOSFET and the source of the low-side MOSFET. This capacitor reduces the noise and the power loss of the MOSFET. ISL6253 Quad Flat No-Lead Plastic Package (QFN) Micro Lead Frame Plastic Package (MLFP) 2X L28.5x5 28 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE (COMPLIANT TO JEDEC MO-220VHHD-1 ISSUE C) 0.15 C A MILLIMETERS D A 9 D/2 D1 D1/2 2X N 6 INDEX AREA 0.15 C B SYMBOL MIN NOMINAL MAX NOTES A 0.80 0.90 1.00 - A1 - - 0.05 - A2 - - 1.00 9 0.30 5,8 A3 1 2 3 E1/2 b E/2 E1 E 9 0.15 C B 2X 0.15 C A 5.00 BSC - 4.75 BSC 9 E2 A2 A 0.08 C 9 4X P - 4.75 BSC 2.95 3.10 9 3.25 7,8 - 0.50 BSC - k 0.25 - - L 0.50 0.60 0.75 8 L1 - - 0.15 10 N 28 2 7 3 8 Ne 8 7 P - - 0.60 θ - - 12 7 NX k D2 2 N 4X P 1 (DATUM A) 1. Dimensioning and tolerancing conform to ASME Y14.5-1994. 8 3. Nd and Ne refer to the number of terminals on each D and E. 4. All dimensions are in millimeters. Angles are in degrees. 9 CORNER OPTION 4X (Nd-1)Xe REF. 9 2. N is the number of terminals. E2/2 N e 9 NOTES: (Ne-1)Xe REF. E2 7 NX L 3 Rev. 0 02/03 2 3 6 INDEX AREA 5. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. BOTTOM VIEW 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be either a mold or mark feature. A1 NX b 5 C L 7,8 Nd D2 8 3.25 0.10 M C A B 5 NX b (DATUM B) A1 A3 SIDE VIEW 3.10 5.00 BSC e / / 0.10 C C SEATING PLANE 2.95 E1 0 4X 9 D E B TOP VIEW 0.23 D1 D2 2X 0.20 REF 0.18 7. Dimensions D2 and E2 are for the exposed pads which provide improved electrical and thermal performance. 8. Nominal dimensions are provided to assist with PCB Land Pattern Design efforts, see Intersil Technical Brief TB389. SECTION "C-C" C L L1 10 L L1 e 10 L e C C TERMINAL TIP FOR ODD TERMINAL/SIDE FOR EVEN TERMINAL/SIDE 21 9. Features and dimensions A2, A3, D1, E1, P & θ are present when Anvil singulation method is used and not present for saw singulation. 10. Depending on the method of lead termination at the edge of the package, a maximum 0.15mm pull back (L1) maybe present. L minus L1 to be equal to or greater than 0.3mm. ISL6253 Shrink Small Outline Plastic Packages (SSOP) Quarter Size Outline Plastic Packages (QSOP) M28.15 N INDEX AREA H 0.25(0.010) M E 2 SYMBOL 3 0.25 0.010 SEATING PLANE -A- INCHES GAUGE PLANE -B1 28 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE (0.150" WIDE BODY) B M A D L h x 45° -C- α e A2 A1 B C 0.10(0.004) 0.17(0.007) M C A M B S NOTES: 1. Symbols are defined in the "MO Series Symbol List" in Section 2.2 of Publication Number 95. 2. Dimensioning and tolerancing per ANSI Y14.5M-1982. MIN MAX MILLIMETERS MIN MAX NOTES A 0.053 0.069 1.35 1.75 - A1 0.004 0.010 0.10 0.25 - A2 - 0.061 - 1.54 - B 0.008 0.012 0.20 0.30 9 C 0.007 0.010 0.18 0.25 - D 0.386 0.394 9.81 10.00 3 E 0.150 0.157 3.81 3.98 4 e 0.025 BSC 0.635 BSC - H 0.228 0.244 5.80 6.19 - h 0.0099 0.0196 0.26 0.49 5 L 0.016 0.050 0.41 1.27 6 N α 28 0° 28 8° 0° 7 8° 3. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. Rev. 1 6/04 4. Dimension "E" does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 5. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area. 6. "L" is the length of terminal for soldering to a substrate. 7. "N" is the number of terminal positions. 8. Terminal numbers are shown for reference only. 9. Dimension "B" does not include dambar protrusion. Allowable dambar protrusion shall be 0.10mm (0.004 inch) total in excess of "B" dimension at maximum material condition. 10. Controlling dimension: INCHES. Converted millimeter dimensions are not necessarily exact. All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation's quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 22


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Today, I visited Yahoo web site and found some interesting pictures which people emailed the most. There were 50 of them, but I chose three to share. Take a look!
This is a giant tornado touching the ground in Orchard, Iowa. A lady took this photo from her front door. Luckily, no one got hurt because the tornao went back up to the cloud. However, I read some news there were other tonados hit the same town and killed four children. That's horrible…
This is a rare photo taken at the aqurium in Atlanta, GA. The male sea dragon is carrying the eggs. I have visited Atlanta many many times, but haven't had a chance to go to the Aqurium yet. Well…almost… I went during the weekend and I believe it was the first week of grand opening. It was crowded, so I didn't get in.
The water overflowing from the Cedar river floods Iowa. The news said people are asked to evacuate. This year, it has to be the worst diaster for Iowa.
I'm not really sure what's going on with all the diaster around the word. It's getting worse and worse. Is it our time to pay back to the mother nature??? Who knows!

subset: commoncrawl


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I'd like to coin a new phrase: Michael Baywatch: When beautiful people run through explosions in slow motion.
The Bad:
I watched Transformers: ROTF because I felt obligated. The G1 series informed so much of my childhood, I had to go. Granted, the 1980s cartoon movie, if watched at a distance, is pretty cheesy. My emotional connection to my childhood is what makes it my favorite movie.
The high point of the movie for me was the trailer for Harry Potter.
Just like the first one, the changes in Transformers are not what bothered me. At first, I was upset that they actually made Bumblebee cooler by turning him into a Camaro. But now, I've come to expect some changes.
What bothered me was poor scriptwriting, sloppy scifi, continuity problems, lack of plot, lack of character…
Basically, if it wasn't a Transformers movie, I wouldn't have watched it. Or cared enough to post about it.
A lot of people are saying to ignore the plot holes and just enjoy the fun ride. But Iron Man and Dark Knight showed us that you can have both: A whirlwind action-adventure thrill ride that has great characters and story.
Saying that "It's just giant robots fighting, don't expect much" insults Transformers.
Again, the cartoons I grew up with weren't Shakespeare. But they had characters and stories.
I still think this movie, and the last one, are monster movies. Giant aliens with no discernible personality are trying to destroy the world. It ignores the fact that the best thing about the toys when I was a kid was that there were personalities. Example: G1 Swindle. Toy was decent but it was the personality that was great. Mirage. Wheeljack. I could go on and on.
In monster movies, a person gets about 3 lines of dialogue and is killed. They don't have a character, they have one character trait. Sound like ROTF?
Roger Ebert's review is very poignant. It's where I grabbed the Iron Man and Dark Knight thing from. He also said how a child can hold a Transformer toy and use his imagination to craft wonderful stories. And that ROTF was certainly not the work of a vivid imagination.
Some questions:
-If the Allspark created all Transformer life, why does it only make evil robots?
-Why does it take a Matrix of Leadership to bring Prime back to life, but Megatron can just be rebuilt on the ocean floor?
-Why is Megatron such a putz? He shows up on Earth, gets frozen. Gets thawed out, killed by a fleshling. Wakes up again only to kowtow to some ancient Cybertronian. I want my villains better than this.
-During the first fight, a human died. They showed his coffin. Was he in the first movie? Was he supposed to be important?
-How is Optimus a descendant of the primes? Do they have babies?
-Was Ironhide British in the first one?
-How did the government scramble a huge attack force to come in what seemed like seconds?
When Megatron called to Starscream for help at the end of the movie, Starscream should have looked around to make sure no other Decepticons were looking, then said "I'll tell the others you fought bravely." Then killed Megatron. That one simple action would have changed a lot of my opinion about the movie.
This should have been a kids' movie.
A Bot firing a crotch-mounted cannon; constant testicle jokes; dogs humping; a bunch of cursing; an impossible to ignore drug scene; John Turturro's thong (OK, that part was kind of funny, but still). The ratings board must have been out for popcorn during some of this.
I would be mortified to have my nephews here. My daughter is 2 and loves Optimus Prime. (She calls him Op-pa!) I think, when she's older, I'll have her watch G1 but not the new movies. Kind of like how I'll have her watch Star Wars Eps 4-6, not Eps 1-3.
It's kind of bad when Turturro had to actually ask Jetfire what the plot is.
Plot derives conflict: Character A wants to do something, but Character B wants to stop that. To a degree, there was some of that. But what we got was "There's some big thing we have to destroy before it blows up the sun." When Hitchcock was asked to define a MacGuffin, he said the audience doesn't care what it is, as long as it drives the story.
Iron Man had a MacGuffin in it, too, the rings that created his power-core-heart-thingy. And the first Batman had the microwave emitter. Dark Knight didn't have a MacGuffin, and that's why it was brilliant.
There was comic relief, but no comedy.
The difference is that comedy flows naturally out of the story or characters. Comic relief is injected, forced into a movie. A robot calling a human a "pussy," for instance. Jetfire's routine "My father was a wheel…." was hilarious. But it shouldn't have been in the movie. A lot of the gags, like a robot humping a girl's leg, should have been in the Scary Movie franchise instead.
About the Jar Jar Bots. Much has been made to say they were racist black stereotypes. I didn't get that. I hated them, yes. But I thought they were rednecks. I didn't see the correlation.
The Good:
I think I'm being overly critical, so I'll talk about what I liked.
I think Sam and Mikaela are very charismatic. They're not necessary to the movie. But they're likable.
I enjoyed Sam's parents (minus the drug scene.) I liked them in the first one, too.
Any fight scene with Prime was amazing. If he wasn't there, it was kind of blah. But whether it was slo-mo or what, you could really see what the characters were doing. It was a lot of fun to watch those fights. The 3-on-1 where Prime died; his return to take on Megatron and the Fallen; even Jetfire vs. Scorponok; Bumblebee vs. Rampage and Ravage.
And Bumblebee is making up for lost time. He stopped getting his butt kicked and started kicking butt.
There was one point where Ironhide was hurting pretty badly. No incarnation of Ironhide has ever been my favorite, but I was actually sitting there hoping he wouldn't die.
Megatron and Starscream playing the roles that we're used to seeing.
Soundwave and Frank Welker's voice. Soundwave was always one of my favorites. I was curious to see how they were going to use him. The satellite was an interesting idea.
Ravage. Another one of my favorites. Done very well, I think.
This is a version of Transformers 3 I made myself based on what I think the script should be:


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You may have heard of superfoods, those foods that have high concentrations of health-enhancing nutrients. Cacao, chia seeds, goji berries and blue-green algae are just a few examples. Many of these foods are traditionally used by indigenous cultures and have been in use for thousands of years. Super foods can boost the functioning of particular organs or bodily systems and can also address overall health. Let me, Jody Kriss, guide you through this and achieve better health!
To get started exploring these nutritional powerhouses, here are a few guidelines:
1. Start where you are (how you feel and want to feel, what appeals, what seems accessible).
2. Explore one category at a time (green, fruit & nut, bee superfoods, fermented foods, seaweed, herbs)
3. Start seasonally – certain foods are more useful in specific seasons. For example, green superfoods are good for spring and summer, whereas some of the stronger fermented ones are too cooling for mid-winter. Choose one or two foods to try at a time, especially paying attention to how they fit the season.
Green Superfoods
Green superfoods are filled with chlorophyll, which makes them cleansing, cooling and energizing. Perfect for summer. They have the highest concentrations of easily digestible nutrients, fat burning compounds, vitamins and minerals to protect and heal the body. They contain a wide array of beneficial substances including proteins, protective phyto-chemicals and healthy bacteria helping you to build cleaner muscles and tissues, aid your digestive system function and more effectively protect you against disease and illness.
Here are Jody Kriss' recommendations on a few green superfoods to try:
• Wild Bluegreen Algae (try simplexityhealth.com) – Algae was the first form of life on Earth and its power is immense. Wild blue-green algae is a phyto-plankton and contains virtually every nutrient. With a 60% protein content and a more complete amino acid profile than beef or soy beans. It contains one of the best known food sources of beta carotene, B vitamins and chlorophyll. It has been shown to improve brain function and memory, strengthen the immune system and help with viruses, colds and flu.
• Spirulina – Spirulina is a cultivated micro-algae which has been consumed for thousands of years by the indigenous peoples in Mexico and Africa. It is one of the highest known protein sources on Earth and contains 70% complete protein, towering over steak which consists of only 25% protein once cooked. Studies have shown that spirulina can help control blood sugar levels and cravings thus making it a key food for diabetics, and can be used to assist in weight loss and as a general nutritional supplement.
• Chlorella – Chlorella is a fresh water algae and like its other algae cousins contains a complete protein profile, all the B vitamins, vitamin C and E and many minerals. It is amazing for the immune system and for reducing cholesterol and preventing the hardening of the arteries, a precursor to heart attacks and strokes.
• Wheat Grass – Wheat grass is the sprouted grass of a wheat seed. Unlike the whole grain, because it has been sprouted, it no longer contains gluten or other common allergic agents. Wheat grass is super alkalizing and is excellent for promoting healthy blood. It normalizes the thyroid gland to stimulate metabolism thus assisting digestion and promoting weight loss due also to its high enzyme content and cleansing effect.
• Green Leafy Vegetables – Green leafy vegetables are so readily available and so highly nutritious, however most people do not eat enough of them. Studies continuously confirm that populations that eat a diet high in green leafy vegetables run a far lower risk of heart disease and cancer. Fresh raw green leafy vegetables contain high doses of chlorophyll, easily digestible proteins, enzymes and a wide range of vitamins and minerals. These particular vegetables act as mini-transfusions for the blood, a health tonic for the brain and immune system and a cleanser of the kidneys. Try any of the following: rocket, spinach, dandelion greens, kale, watercress, parsley, lettuce, endive, chicory, broccoli sprouts and mustard sprouts.
• Green smoothies (basic recipe): A few chunks of apple or pear; A dash of juice or coconut water, if desired; A tablespoon of almond or other nut butter (optional); One to three leaves of kale; Half cup or so of ice. Blend all until icy and smooth.


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For some people, consuming a caffeinated drink such as coffee won't have any side effects. Others, however, can experience a long list of changes to their body and mind, especially if they drink multiple cups. The causes of panic attacks and panic disorder, which describes those who have frequent attacks, can vary greatly. In some cases, caffeine can trigger a panic attack.
Shaking, Shortness of Breath and Fear
Although many people experience varying degrees of general anxiety, the Anxiety and Depression Association of America reports that 6 million Americans have panic disorder. When you have a panic attack, you can experience symptoms such as uncontrollable shaking, dizziness, shortness of breath and sweating or chills. Panic attacks can also generate strong fears of death or loss of control, and you might also feel as though you're choking.
Genetic and Emotional Causes
The causes of panic attacks and disorder aren't set in stone. The National Institute of Mental Health reports that while the issue can run in families, experts are unsure of exactly what causes it. In addition to genetic causes, the American Psychological Association notes that panic attacks can also result from stress. For example, a person might have a panic attack due to a particularly stressful state of mind, perhaps after the loss of a loved one.
Caffeine's Link With Panic Attacks
The APA notes that because the cause of panic attacks is largely speculative, it's possible that some people can experience an attack after consuming caffeine. The organization also reports that the physiological changes that result after consuming caffeine can lead to a panic attack. For example, if you experience an accelerated heart rate as a result of your caffeine intake, you might mistakenly believe you're having a panic attack. The panic you experience can then lead to an actual panic attack.
Skip the Caffeine
Caffeine has several potential side effects, including a rapid heart rate and anxiety, that can be problematic to those who experience panic attacks or disorder. As such, MedlinePlus suggests that limiting your intake of caffeine or removing it from your diet entirely might lead to fewer attacks. Your body doesn't need caffeine to function, and its stimulating effect can be problematic, especially if you consume more than 300 milligrams per day.


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Definitions of lump
n. - A small mass of matter of irregular shape; an irregular or shapeless mass; as, a lump of coal; a lump of iron ore. 2
n. - A mass or aggregation of things. 2
n. - A projection beneath the breech end of a gun barrel. 2
v. i. - To throw into a mass; to unite in a body or sum without distinction of particulars. 2
v. i. - To take in the gross; to speak of collectively. 2
v. i. - To get along with as one can, although displeased; as, if he does n't like it, he can lump it. 2
The word "lump" uses 4 letters: L M P U.
Direct anagrams of lump:
Words formed by adding one letter before or after lump (in bold), or to lmpu in any order:
a - ampul b - plumb c - clump e - plume f - flump p - plump s - lumps plums slump y - lumpy plumy
Shorter words found within lump:
lum mu pul um ump up
List shorter words within lump, sorted by length
Words formed from any letters in lump, plus an optional blank or existing letter
List all words starting with lump, words containing lump or words ending with lump
All words formed from lump by changing one letter
Other words with the same letter pairs: lu um mp
Browse words starting with lump by next letter
Previous word in list: lummoxes
Next word in list: lumpectomies
Some random words: bub roach bwana rance ocher aorist kea
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Life is a journey and my life has been full. I've been married 35 years to the same woman and we have been blessed with three children, all grown. I live in suburbia and I am a state worker. I live an unremarkable existence except for one thing.
Eight years ago, I was able to volunteer to become a participant in a prison ministry program. This came to pass after my participation in church sponsored small group-sharing program where I met a man named Paul who was doing this prison ministry. It has become the most meaningful thing I do in my life. My beliefs have been changed from the perfunctory cultural to the truly spiritual. I visit a local jail about 40 miles from home. As a member of a team of about 15-20 men, each of us prepares a talk that are intended to break the ice or give a message about our faith. We tell personal stories of our own lives to 55 to 65 inmates we call residents. Over three days, 6 to 8 residents and I are seated at tables where I share time and eat meals. In between talks I am free to converse personally and informally to an incarcerated resident. This process called 'table talk' is the stuff of spiritual awakening for the resident and me alike. After 3 days I haven given intimate details of my life to them and they do the same. I also give letters of encouragement to each inmate on the retreat. Every volunteer does this. I also solicit grade school children to write letters of encouragement. The effect these anonymous letters is awesome. A child's writing may touch places in a residents' heart where adults and the penal system cannot penetrate.
The residents and I go from skepticism and mistrust to new friends. After 14 such retreats I have some of the same team members and resident friends since my first retreat. Some have been paroled and I believe because of the prison ministry, positive change happens for them, and they do not commit new crimes .What has become real for me is the vital spiritual life that exits in jail. It is a privilege to know these residents and to listen to their trials and tribulations and to witness the spiritual change in their hearts. This change is called 'metanoia' and though faith, God changes them. I can see it in the faces of these men. This ministry has also changed me. Moved by these retreats, done twice a year in this particular jail, I joined a Bible Study there on Wednesday evenings five years ago. Currently a former resident and I bring scripture to the residents. That's were I learned the meaning of metanoia. There is the story of man named Paul of Tarsus and his conversion via God from a Roman persecutor of Christians to a most strident propagator of the good news. As pagans, the Romans beheaded him for his beliefs. Prison ministry and Bible study have buoyed my beliefs and it is I where learned the two rules for living life: Love God with all your heart and love your neighbor as yourself. I have come to know and feel God's love for me through the prison ministry. It is said, faith without works, is dead. I try to make real and live out the 2nd rule of my faith by treating residents as I would like to be treated; and they do the same. With God's help, the fruits of prison ministry in the form of metanoia, changes hearts. This I believe.
If you enjoyed this essay, please consider making a tax-deductible contribution to This I Believe, Inc.


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The Naked Jungle1954
The Naked Jungle (1954)
The Naked Jungle Photos
Movie Info
Watch it now
as Christopher Leiningen
as Joanna Leiningen
as Commissioner
as Incacha
as Boat Captain
as Medicine Man
as Gruber
as Kutina
as Zala
as Foreman
as Gruber's Indian
as Fat Man
as Indian
as Indian Boy
as Indian Wife
as Indian Lover
as Gruber's Indian
as Indian
as Indian Husband
Critic Reviews for The Naked Jungle
All Critics (7) | Fresh (6) | Rotten (1) | DVD (1)
Lively tale in which the characters are even more interesting than the adventure.
Das Kapital in the heart of darkness
Those blasted ants! Fill the moat! Pretty creepy critters here.
a schizophrenic little drama
Audience Reviews for The Naked Jungle
While the prospect of Charlton Heston fighting ants is WAY cool, the character Heston plays is not. He is one of the biggest douches in cinema.
Super Reviewer
Actually has some plot beyond the killer ants.
Super Reviewer
The Naked Jungle Quotes
There are no approved quotes yet for this movie.


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Chelsea Handler insists Bill Cosby is guilty from firsthand experience
Bill Cosby might have some people convinced that he is innocent of all the recent sexual assault allegations, but there's one person that doesn't need to hear any of the details to know that the reports are true, and her name is Chelsea Handler.
More: Bill Cosby rape scandal: Where is Phylicia Rashad in all of this?
During an interview with Esquire, the comedian casually mentioned that she had her very own situation with her fellow stand-up comedian. Mid-conversation about sexual routine, Handler told the magazine about the time she had one scary encounter with the funnyman in Atlantic City. As her story goes, Handler was doing stand-up in the same hotel as Cosby many moons ago, and sometime during the afternoon, a hotel rep told Handler that Cosby wanted to meet up with her in his hotel suite.
"This was like 10 years ago. And I said, 'That's really weird. I don't want to go alone. I go, I don't know him," she recalled. Handler said she had a small production crew of men with her at the time because she was filming something, so she brought them up with her and couldn't be more thankful that she did.
Even though it's been months since allegation after allegation have flooded the media, Handler says she didn't think about her encounter with the comedian until just recently when her friend sent her a text, reminding her of the scenario. Yikes!
"He said, 'Hello! You could've been one of his victims if we weren't there.' And I went, 'Oh my gosh…' Yeah, so yeah, he's guilty," Handler concluded.
More: Bill Cosby's first video message is so awkward, it's hard to watch
Handler is just the latest female to come forth with sexual assault accusations against Cosby. Even though he's remained silent on the subject, it appears that the overload of accusers has already swayed the public's opinion on the former beloved funnyman.


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Labrador retrievers are smart, energetic dogs, so most tips for training a puppy relate to channeling their energy and keeping them engaged. Otherwise, Labrador puppies need the same basic care as other puppies.
First, Labrador puppies need a safe environment. While they can withstand extremes of temperature, they feel more comfortable in cooler temperatures. The puppy shelter should be well-ventilated in the summer. Puppies also need shade and a lot of fresh water.
Labs love to run. However, they should never be allowed to run unsupervised. A fenced yard is ideal. Full-grown Labradors can jump as high as 6 feet, so a tall fence with a coyote guard is best. Gates and doors need to be securely latched and locked, because Labs are notorious escape artists.
Spend at least 10 minutes a day training the new puppy. For their safety, Lab puppies need to learn how to sit and how to heel. This allows the owner to secure the dog in case of danger. Since Labs are so eager to please, training should be reward-based. While treats are helpful, Labrador puppies are ecstatic to receive praise and attention from their owners. Whatever the chosen method, keep it consistent so the dog does not get confused.
Labradors instinctively do not like to urinate or defecate where they sleep. Therefore, crating puppies at night is an effective way to house train them. Otherwise, frequent trips outdoors with verbal commands and rewards work for house training a Lab puppy.


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In the business world, there are people who surpass expectations � not necessarily for personal gain, but to show gratitude for being employed, and to help the company or organization succeed.
In the business world, there are people who surpass expectations � not necessarily for personal gain, but to show gratitude for being employed, and to help the company or organization succeed.
And there are those who care nothing about the company or excelling. They complain about having to go to work, and grudgingly do the bare minimum � less, if they can get away with it. Still, they take home the company or organization�s money in the form of a paycheck.
As a college student, during the summer, I worked in a factory that manufactured plastic pipe fittings. I made sure the machines were constantly supplied with necessary raw materials. If a machine ran out, it would �blow up� and stop production for more than an hour.
The job was enjoyable, but not very challenging.
While working the day shift, I observed people who concentrated on doing their jobs and doing them well.
As I worked the graveyard shift, I observed a different work mentality. Because management was not around, and there were corners with no lights, it was common to see people sneak off, rest, eat or nap.
I didn�t understand that mindset. I had been hired to do specific tasks, but I was not going to do just the bare minimum. I was going to fulfill my responsibilities, and when those were done, find more to do.
Would you believe that in the Bible there are minimum requirements for being considered a Christian? Bare minimums are belief in the existence of God, our creator; and that Jesus Christ is Immanuel, "God with us," and that he died on a cross so the sins of those who believe in him could be forgiven. The bare minimums also include the belief that God�s Holy Spirit is his presence among us, working in and through us to accomplish God�s will on this earth.
More is needed to grow in faith and excel. This includes a change of mind and heart, and putting our faith into action. We change from thinking about and living only for ourselves, to living completely for Jesus Christ.
What God requires of us is a life lived with acts of justice, kindness and humility, which are lived as a result of our faith.
Don�t try to get by doing just the bare minimum. Do your utmost to excel in your faith journey!
The Rev. Mark Broadhead is Laurel Hill Presbyterian Church and First Presbyterian Church of Crestview�s pastor.


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All Films.All Above Board.NOW INCLUDES TV SHOWS & TV LISTINGS
A military experiment to create a time machine backfires, leaving a doorway open between the present and a horrific future. Monstrous creatures journey back in time to go on the rampage, and a group of soldiers is tasked with shutting down the gate before any more get through. Sci-fi horror, starring David Hewlett, Christina Cole and Robert Picardo


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Young wants to redefine' role of county government
Incumbent county commissioner wants to address rules and regulations already in place
Frederick County Commissioner Blaine R. Young (R) wants the next county board to toughen up and curb government spending in an effort to leave as much money as possible in the wallets of the average taxpayer.
Young said he is running in the Sept. 14 Republican primary in hopes of "redefining" the role of county government, by prioritizing services and funding those that are essential to residents.
"I've knocked on a lot of doors and people are upset and feel spending must be reined in," he said. "People want to spend their own money. They feel it's better than the government spending it."
Young said when the economy was in good shape, money was spent and government services and programs were expanded. Now the economy is struggling and the financial picture is bleak, so the next board must prioritize services that should be funded.
Young considers education, police, fire and rescue, roads, sewer, water and trash disposal essential services. "These services are vital to our health and wellbeing and are traditional government services," he said.
Young also wants job creation to be a major objective of the next board.
As a business owner, Young said the county must become more "friendly" to other businesses that want to expand and relocate to Frederick. But Young stresses that he is not in favor of businesses that get financial handouts from the government.
"I'm not for corporate handouts and I don't think we should be handing out cash from taxpayers to businesses, to get started," he said. "But I do think we need to be more aggressive and work with the business community. We need a whole new cultural change in attitude toward business. We need to be as aggressive as possible and foster a business-friendly attitude, but not with corporate welfare."
Young said "strangulation by government regulation" must stop. He believes that with government out of the picture, more jobs will be created in the county.
Young, who was appointed to the Board of County Commissioners on March 3 to fill the seat of Charles Jenkins, wants to address the many government rules and regulations already in place.
"There are so many rules, regulations and fees," Young said. "One of the first things I would do is to make a motion not to adopt any new regulations for a year. Then we need to re-evaluate every regulation in place and see if it serves its purpose. Government is not the solution to every problem. Some things can be figured out by themselves and not by this board. Government is not the answer."
Finally, Young vows to serve only one term if elected.
He said he would rather dedicate his time to his wife and sons, manage his cab company, and get back to hosting his political talk radio show.
Young believes that a new board of county commissioners every four years will bring fresh and innovative ideas. "I don't want to become part of the problem," he said.
-Residence: Monrovia
-Age: 38
-Family: Married, four children
-Party: Republican
-Education: Bachelor's degree in mass communications from Frostburg State University; associate degree from Frederick Community College; graduate of Gov. Thomas Johnson High School
-Work experience: Co-owns Yellow Cab of Frederick; owner and operator of Interstate Mobile Advertising; talk show host on 930AM WFMD
-Top three issues: Budgetary management, job creation and easing up on county government regulations that are imposed on businesses.
-Previous political experience: Alderman for the City of Frederick (1997-2001)
-Other affiliations: National Rifle Association, Monocacy Pistol Club, Izaak Walton League, Fishing Creek Rod and Gun Club, Sons of the American Legion, Sons of the Amvets, Moose Club, Eagles Club, Redmens Club, Owls Club, the ARC's Endowment Fund, Frederick Memorial Hospital Good Samaritan Fund, Frederick County Chamber of Commerce, Southern Frederick County Rotary Club
-Website: www.BlaineforBOCC.com


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Katy saw the shadows. Gremlins, ghouls, dark castles and eyes. Universe stapled onto universe, dreams flittering across buildings and the streets. Signs, ephemeral art work from some sixth place, a strange creeping window into spaceless space. What was she seeing? Did these shadow glimpses occupy her time now, or were they from somewhere else?
Were watching her?
Filed under: Night Visions, Perdu | Tagged: glimpses, night, overlay, shadows, sixth space, space & time, space and time, universe, watching | Leave a comment »


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January Term
January Term Session Dates:
January 7 - January 25, 2019
What can you accomplish in three weeks? How about earning credits towards your degree or building professional work experience through an internship? You can even travel to a few intriguing cities to explore an artistic discipline that may not be all that familiar to you.
Tisch January Term courses in New York City, Los Angeles, Washington, D.C., Havana, Paris, and Sydney are open to NYU and visiting undergraduate students, including international students. This is an opportunity for you to complete degree requirements or pursue personal interests in various artistic disciplines. For-credit and non-credit courses are available. Session dates may vary by program.


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Whether you're just starting out or looking to take the next leap in your career, a mentor is a fantastic way to gain insight and knowledge about your chosen industry. You might be great at what you do, but it never hurts to foster a relationship with expert in their field who can offer guidance, access to important industry contacts, and general encouragement to keep you moving forward.
Don't ask a random
Unless you're at a particularly boozy networking event, a great mentor won't just fall into your lap. Asking a complete stranger is probably going to end up a bit awkward. Most experts agree that it's generally best look within your own network, and it should happen organically:
"If someone has to ask the question, the answer is probably 'no'. When someone finds the right mentor, it is obvious. The question becomes a statement. Chasing or forcing that connection rarely works," says Facebook COO, Sheryl Sandberg, in her book 'Lean In'.
At the same time…
You can make yourself known to influencers in other ways… If you follow a particularly interesting person on Twitter or LinkedIn you can retweet or share their posts, reply with insightful comments, or even start a discussion based on their post (tagging your desired mentor of course!).
Go for the person, not the position
We'd all love to be mentored by the CEO, but let's be honest – he or she probably won't have the time or interest to invest in your career. Instead go for someone who is 5-10 years ahead of you career-wise who has the right personality and time to invest in you.
What's in it for them?
If there's a colleague or acquaintance within your network with whom you have a natural rapport, foster that relationship by shouting them a coffee and going for an informal chat.
Be enthusiastic, reliable and flexible with your time. Most importantly – be good at what you do. Any mentor worth having will want a mentee worth having!
Be the mentee you think someone would love to coach. Okay, sounds a tad close to 'Be the change you want to see in the world', but hey – cheesy affirmations are often on point.
Don't be too sensitive
If you're having a hard time getting on to your potential mentor or they're slow to respond, perhaps they are just too busy and it's not the best time for them to be a mentor.