Monolithic Integration of an Active Clamping H-Bridge for Isolated Forward DC-DC Converters

摘要

Conventional active clamping circuits for driving the pulse transformer in isolated forward DC-DC converters put considerable voltage stress on the DMOS power devices at high duty ratio. This is not so much an issue for an implementation based on discrete DMOS components, but monolithic integration becomes nearly impossible. This paper presents a new 4-transistor active clamping H-bridge topology that significantly reduces the voltage requirements and allows integration in a junction-isolated smart-power IC technology.