Research on design of synchronous buck digital power supply based on average current mode

Abstract

High efficiency, high switching frequency and digital control are the research hotspots in the field of switching power supply in recent years. In this paper, the design strategy of synchronous buck digital power supply based on average current mode is discussed. Combined with theoretical analysis and Matlab/Simulink software simulation, the loop control design conditions of synchronous buck are analyzed, two design methods of voltage and current double closed-loop PI compensator are described in detail, and a voltage loop control design method based on the simplification of the current loop is proposed. The high-performance mainstream MCU chip STM32G474 is used as the control core, and the high-resolution PWM technology is used to realize a switching frequency of 200 kHz, and the architecture of the system software is constructed with the idea of interrupt event triggering and state machine operation. The simulation and experimental results show that the system has the characteristics of high efficiency, fast dynamic response and strong robustness, which provides a reference for the general design of digital power supply.

Keywords

• synchronous buck
• double closed-loop pi control
• average current mode
• digital power