Design of High Precision and Wide Range Current Source Based on Microcontroller

Aiming at the requirements of high-stability and high-precision constant current source of various low-voltage electrical appliances in the performance testing, a high-precision numerical controlled direct current source with AT89S52 microcontroller is designed. The system consists of control circuit, constant current source, display, D/A and A/D conversion circuits. In the numerical control part, the D/A converter DAC0832 is used to control the output current of the voltage controlled constant current source, and the output current of the voltage controlled constant current source is measured and fed back by the A/D converter ADC0804 in real time. The use of independent keyboard as the current output setting device, which also facilitate adjusting the setting current in stepping mode; LCD1602 shows the setting current and the actual output current. Experiments show that the output current of the constant current source can be set within 10~2000mA with small ripple current, and the current can also be adjusted in stepping mode by the keyboard.