Design Of A High-Precision Dc Regulated Power Supply System

DC regulated power supplies are widely used in teaching, scientific research, industrial production and other fields. The accuracy of the power supply in the automatic test system will affect the quality of the test results. In order to design a high-precision DC regulated power supplies, based on closedloop negative feedback and self-calibration technology, we use four-wire Kelvin sense and fuzzy adaptive PID control algorithm to improve the accuracy of the output's power, while floating output method has also been used to simplify the design. A microcomputer has been used to control a DAC which outputs a analog voltage to drive a power amplifier, in this way, the power amplifier could output a adjustable voltage with continuously. At the same time, a ADC has been used to sample the amplifier's output and send the sample value to the microcomputer for negative feedback control. A power dissipation control circuit has been designed based on the junction temperature characteristics of the power amplifier to improve power conversion efficiency and accuracy. The experiment test results show that the designed power supply's output voltage range is 0 similar to +/- 30V, accuracy is +/- (0.25% U +/- 10mV), current range is 0 similar to +/- 6A, accuracy is (0.2% * I +/- 5mA), maximum power is 65W, which meets the expectations target.