Line‐transient enhancement techniques for multi‐path hybrid DC–DC converter with <1% output overshoot/undershoot

Abstract

This letter presents two transient enhancement techniques for multi-path switched-capacitor-inductor (MP-SCI) hybrid DC–DC converters to eliminate the line-transient-induced voltage coupling to the converter output. Since the existing input-feedforward method is hard to apply to the MP-SCI converter, the proposed techniques tackle the intrinsic hard-charging property with the MP-SCI topology, preventing the line-coupling current through topology operation reconfiguration and power-switch modulation. The proposed controller also achieves adaptive line-transition detection and automatic flying-capacitor voltage balancing, ensuring a fast line regulation feature. Implemented with an MP-SCI topology for a 9 to 14 V-input to 5 V-output conversion, the proposed control techniques provide an output (VOUT) overshoot and undershoot as low as 0.5% of the output DC level under a 3-V input voltage step. From the simulation, the corresponding output variation reduction can be more than 94% when compared with the existing MP-SCI operations. Besides, the proposed controller is compatible with a voltage-mode (VM) V2 pulse-width modulation (PWM) function, achieving a fast load-transient recovery in six switching cycles and a VOUT variation of 75 mV at a 5 V DC level under a 0-to-3 A load step. The peak conversion efficiency can be as high as 95.5%, and the targeted load current delivery is up to 3 A.