Session 2-4

Fixed-Frequency Adaptive-On-Time Boost Converter
with Fast Transient Response and Light Load Efficiency Enhancement
by Auto-Frequency-Hopping

 

Abstract

An integrated fixed-frequency adaptive on time DC-DC converter with fast transient response and high light load efficiency is presented. To achieve fixed frequency at continuous conduction mode, the on time is adaptively controlled to force the switching frequency tracks the reference frequency with less than +/-0.5% error within the whole operating range. To enhance the light load efficiency as well as reduce EMI noise problem, the on time is adjusted to maintain the switching frequency hops between 1MHz and 1MHz/N where N = 2i and i = 1 to 5 according to the loads without load current sensor.