A 1500mA, 10MHz on-time controlled buck converter with ripple compensation and efficiency optimization

A 10MHz self-adaptive on-time controlled buck DC-DC converter with optimized efficiency over full load range is presented. A low-cost passive ripple compensation scheme (PRC) and a self-adaptive on-time generator (SAOTG) are proposed to solve the system stability and frequency variation problem. Meanwhile automatic power transistor sizing (APTS) technique is used to improve the overall efficiency especially in heavy load. The converter has been implemented in 2P4M 0.35μm CMOS process. The measurement results show that the output ripple is smaller than 10mV and the overshoot of load transient response is realized as small as 8mV @ 200mA step. With APTS technique in ultra heavy load and PFM control in light load, the efficiency keeps over 81% for load range from 20mA to 1500mA and the peak efficiency reaches 88.43%.