Design and evaluation of a high-speed MOSFET-based current sink for enhanced dynamic load testing of DC–DC converters

Verification of the dynamic load transient response of DC-DC converters is an essential process for modern semiconductor devices such as CPUs, GPUs, etc., which require rigorous power supply testing. Conventional electronic loads cannot achieve the rigorous testing conditions of low voltage, high current and high current slew rates. To solve this problem, a novel high-speed variable current sink with a MOSFET-based load is proposed in this study. The proposed device features a linear controllable current from 0 A to 120 A, a scalable and compact footprint, and negligible electrical noise. For stable step response, an optimally compensated control system with 29.95 MHz bandwidth and 51.14° phase margin is used. The study finally demonstrates that this load device can deliver excellent performance with a current slew rate of >900 A/µs and peak load current of 120 A directly sourced from a 1 V power source.