Design Of High-precision Digital Control Regulated Power Supply

Electrical equipment is used to be powered by rectifier. The output voltage of rectifier will be changed with the alternating of AC power grid or load current. But lots of electrical equipments such as refined electrical testing equipment, auto controlling equipment, and computer etc, need stabling DC power voltage.The scheme of traditional adjustment tube, whose output is transformed through D/A control and then amplification of the reference voltage to control the output of the stepping motor, is mainly used to control the double counter complete system. After decoding, the decimal counter drive digital tube to display output voltage. In order to make the system working properly, we must ensure that double counter work synchronously. Control section work by single-chip microcomputer, the output part will no longer use the traditional adjustment tube. In the D/A conversion later and after stable power amplification,the whole system with SCM is programmable and the system flexibility increase greatly.This design using the MCS-51single chip microcomputer technology designed a kind of output range is0to24volt high precision CNC DC power supply. Design output DC voltage based on the single chip computer as the core and used its conversion function. The system adopts double way and sampling feedback way of working to correct the output voltage; with integrated op-amp and Darlington tube composition power amplification circuit; using a keyboard control and synchronous serial port LED display. The software of system mainly consists of the main program and interrupt program composition. Main program primary process first initialization of unit and mark reset, set communication baud rate and judge the mode of voltage regulation and then acquisition voltage and current real-time upload, and determine whether over current, i f the current is over, the single-chip microcomputer DAC do not output, and pull the voltage low to protect the load, or continue to detection. This paper introduces three system’s main error sources. It simply analysis the error of the quantization,reference voltage WenPiao introducing and introduced by the power to give up. The intelligent microcontroller as the core output of the DC power supply regulation is issued by the PC software interface input digital values adjustable voltage source, and controlled by the MCU conversion adjust the terminal voltage to achieve. To make the adjustment accuracy is improved, using Hall sensors at the same time added to the host computer with the set value of the output voltage by the A/D conversion after forming a closed-loop control, to achieve a precise adjustment of the output voltage used in the design For the output current and the measured current of the sensors is isolated, and the measurement has little effect on the power supply output, to improve the performance of the power supply. The communication module is the current value of the host computer via an RS232interface to communicate with the microcontroller, the set value of the output voltage of the power supply and safety.