A Self-clamping Non-synchronous Duty Cycle Control Strategy for Hybrid Clamping Three-level Buck Converter with GaN Devices

In this paper, a hybrid clamping three-level buck converter (HC-TLBC) with self-clamping non-synchronous duty cycle control is proposed which realizes flying capacitor voltage self-balance. The non-synchronous duty cycle control strategy simplifies the control algorithm which means this topology can be applied in adapter as voltage regulation stage. Compared with traditional control strategy for three-level flying capacitor buck converter, the novel control strategy can make the voltage of flying capacitor clamped in a neutral voltage level in open loop. Meanwhile, the converter is designed based on low NFoM (new figure of merit, NFoM = Rdson×Coss) gallium nitride (GaN) devices, which can achieve higher efficiency. Finally, a 120W prototype is built and it can achieve 99% efficiency at full load.