An adaptive slope compensation scheme for peak current mode Buck converter

Abstract

This paper designs a Buck converter with high transient response speed based on the peak current mode architecture. An adaptive ramp compensation circuit is proposed, which determines the appropriate ramp compensation slope by detecting the switching frequency and duty cycle, reducing the impact of over-compensation on the system's zero-pole position. Simulation results show that the circuit operates normally within the 4.5 V to 24 V power supply range, and the loop waveform is stable under a 75% duty cycle. Under typical conditions of 12 V to 5 V conversion, a 1 MHz switching frequency, and a 1 A load current, the over-shoot and under-shoot voltages of the transient response when the load current jumps by 1 A are reduced by 27% and 34% respectively compared to the optimized circuit, and the over-shoot recovery time and under-shoot recovery time are reduced by 48% and 27% respectively. For the recovery situation under overload conditions, the over-shoot voltage and recovery time are reduced by 50%.