A buck converter using accurate synthetic ripple hysteresis control scheme

This paper presents a dc-dc buck converter using hysteresis current control mode for fast response. A synthetic ripple voltage is proposed to sense the voltage across the inductor and to generate a saw tooth waveform for hysteresis band control. The proposed sensing circuit acts like a low-pass filter and has a local feedback loop to reduce the switching noise. Full chip simulation results indicate that the synthetic ripple slope has accuracy about 95%. The range of the operation voltage of the proposed design is from 2.7 to 4.2V; the low noise design is particularly suitable for portable device with a Li-ion battery power supply.