A 9.3mV Load and 5.2mV Line transients Fast Response Buck Converter with Active Ramping Voltage Mode Control

A fast response active ramping voltage mode control scheme for a Buck converter design is presented. The scheme employs a zero assisted active ramp to accelerate the response of voltage mode control. The design presents an intuitive design guideline for optimal transient responses and the measurement shows superior performances. Fabricated in a 0.8 um BCD process, the prototype converts an input from 10 V and 60 V to an output of 5 V with 600 mA load capacity and 1 MHz switching frequency. Measurements show an under-/overshoot voltage of -12.7 mV and 9.3 mV, respectively, for load transition between 100 mA and 500 mA. The line transient is 5.2 mV and - 3.8 mV, respectively, for input between 12 V and 15 V. The measured voltage scaling speed is 0.15 V/μs with 4.7 μF (x 3) output capacitors and the peak efficiency is 92.6%.