A 10MHz ripple-based on-time controlled buck converter with dual ripple compensation and real-time efficiency optimization

A 10MHz ripple-based on-time controlled buck converter is presented. A novel low-cost dual ripple compensation, which consists in coupling capacitor compensation and passive ESR compensation, is proposed to achieve fast load transient response and robust stability simultaneously. Implemented in 2P4M 0.35μm CMOS process, the converter achieves fix-frequency output with ripple below 10mV and overshoot of 10mV at 400mA step load transient response. With real-time width optimization of power transistors in ultra heavy load and PFM control in light load, the efficiency keeps over 83% for load range from 20mA to 1.5A and the peak efficiency reaches 90.16%.