A 92.7% Peak Efficiency 48/1V DSD Power Converter with 102mV Droop and 1.6µs Settling Time for a 1A/10ns Load Transient

Abstract

With the rapid growth of data centers, the power supply has shifted from 48/12/1V two-stage architecture to 48/1V single-stage. In this paper, a new two-phase sawtooth voltage mode PWM control is proposed for the double step-down (DSD) converter. In order to solve the problem of inherent cycle delay of PWM control, a fast-transient response scheme is proposed. The converter also has a precharge and soft start scheme, which is designed with a 0.18 µm BCD process. It achieves peak efficiencies of 92.7%, 90%, 87.8%, and 86% at 250 kHz, 500 kHz, 750 kHz, and 1 MHz, respectively. During a 1A/10 ns load jump, the undershoot is reduced from 200 mV to 102 mV and the setting time is reduced from 5.3 µs to 1.6 µs.