Design And Implementation Of Multi-channel And Low-power Electronic Load

In modern life, DC power supply electronic equipment, especially DC power supply of intelligent electronic equipment, has been all over people’s lives, and the quality of DC power directly affects the people’s life. With the increasing demand of DC power supply, power supply manufacturers need to detect a large number of power supply products. However, in the market, the multi-channel electronic load is high power electronic load, and the small power electronic load is a single channel.In order to meet the requirements of a large scale of low-power DC power supply’s testing, this paper designed and made a kind of low-power and multi-channel electronic load for DC power supply detection.This paper designed a multi-channel and low-power DC electronic load with a voltage range of 0~30 V and a current range of 0~3 A, which has three kinds of working mode, a constant current, constant voltage, constant resistance. The hardware system is composed of three parts, the main control board, the electronic load module and the human-computer interaction module. The main control board is composed of a control circuit using STM32F107 as the core and a communication module, to complete data processing, and the communication between the screen and the main control board, and the communication between the main control board and the electronic load module. Electronic load module also use STM32F107 as the control chip, and provide the hardware circuit control services and A/D conversion services. In the electronic load module hardware circuit design using the voltage acquisition circuit and the MOSFET driving circuit achieved a constant resistance model based on hardware. In the design of the electronic load module’s program, using the processor’s internal A/D converter,DMA,timer, to ensure the A/D sampling frequency of multi-channel is precisely controlled, which improved the accuracy of A/D sampling. The human-computer interaction module uses the serial port command touch screen as the input and output device, which is responsible for input setting information and display the electronic load module’s return information.In this paper, the constant resistance mode is implemented in hardware. Compared with the constant resistance based on software calculation, it has the advantages of time following, good linearity and high stability. The use of the touch screen makes the DC electronic load can work without the help of the PC, and has good mobility.