Design of bidirectional DC-DC converter based on single chip microcomputer

A bidirectional DC-DC converter based on single chip microcomputer (SCM) is designed by adopting bidirectional buck-boost topology instead of the traditional method of separately designing boost circuit and buck circuit. The converter is designed to achieve charging and discharging functions of five 18650 lithium-ion batteries. The main control chip of the converter is SCM STC12C5A60S2. The IR2104 half-bridge driver with bootstrap function is selected to drive MOSFET for stable turn-on and turn-off. The converter includes sampling circuit formed by the sampling resistor and the op amp op07 and display circuit formed by LCD1602, which can sample and display current and voltage in real time in both charging mode and discharging mode of the converter. In addition, the converter can control the current through keys. The overall system structure is simple, easy to control and low cost. The conversion efficiency is greatly improved using synchronous rectification. In the prototype test, the current fluctuation is small and the voltage stability is high. The designed converter is applied to a small DC motor drive circuit in a laboratory, the motor works well.