LAUSR

This paper proposes a new adaptive ramp voltage mode control scheme. Instead of using the conventional slow compensation path of the voltage mode, the proposed scheme adds an extra feedback path to adjust the amplitude and DC-offset of the ramp signal and to directly accelerate the duty cycle according to the output voltage variation. In addition, a design-oriented analytical method is adopted to intuitively analyzes the loop characteristics and provides accurate instructions for the implementation and optimization of the compensator. A 5–1 V buck converter is implemented in the proposed adaptive ramp control scheme with optimized compensation. Simulation and measurement results show that the converter achieves a bandwidth of up to 591 kHz with a 3 MHz switching frequency and a 65° phase margin. In addition, the undershoot voltage and the recovery time are 16 mV and 19 μs with a load change from 0.5 to 1 A. The proposed control scheme shows superior transient response performance while maintaining fixed frequency operations with a simple system structure.