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Research on large power computer controlled constant current power source technologies

At present, the technology of the small current, low-power and high stability constant current source is more mature. However the technology of high current, high power and high stability computer controlled constant current power source is still in the exploratory stage. After studying the principles of the constant current source and the internal working principle about switching power supply chip L4970, this paper has designed a program of computer controlled constant current source based on the L4970A. The system consists of two parts, the constant current source module as well as the single-chip computer interface control module. The specific working principle and key circuits of the two parts were introduced in detail. After a long test, the constant current can output 0--10A current by the computer-controlled, the accuracy of control is within 2mA, the range of load voltage is 5.1–40V and the efficiency of main loop conversion is up to 92.5%. The constant current source diode has been successfully applied to the heating power of test equipment, which is proved to be stable and reliable.