A 48-to-1 V, 5-A Low-Frequency Step-Down Converter With Bidirectional Recycle Converter for Ripple Cancellation and Transient Acceleration

This article proposes a low-frequency double step-down converter integrated with a GaN-based high-frequency recycle converter. The proposed architecture ensures a sufficiently long on-time of 400 ns while achieving effective output ripple suppression, reducing ripple to 6 mV - an 11× improvement over conventional designs. Leveraging high switching frequency and enhanced inductor slew capability, the converter delivers fast transient response. For a 1-A to 5-A load step, the output exhibits a 69-mV undershoot with a 907-ns recovery time; conversely, a 5-A to 1-A step results in a 74-mV overshoot and an 848-ns recovery time, corresponding to 8.2 mV/A performance. The proposed system achieves a peak efficiency of 96.51%.