Pseudo Hysteretic Controlled Gap Time Modulated Isolated DC-DC Converter With Common-Mode Transient Immunity

Abstract

A pseudo hysteretic controlled gap time modulated isolated dc-dc converter is presented. A pseudo hysteretic controller is designed to bound the output voltage with fast load transient and small output voltage ripple. It implements gap time modulation based on the load current and is used to adjust the power delivered by a Class-D power amplifier (PA) with high efficiency. A high-impedance load shift keying (LSK) scheme is also proposed with common-mode transient immunity (CMTI) to complete the global feedback loop without requiring an additional transformer or capacitor. The prototype is implemented in a standard 65-nm CMOS process. With an input voltage of 2.5 V, the proposed converter generates an isolated output voltage that ranges from 1.8 to 2.2 V with a peak efficiency of 73.3% and an output voltage ripple of only 20 mV. With a load current transient step of 40–150 mA, this converter demonstrates unobservable overshoot and undershoot. CMTI is demonstrated with common-mode transients (CMTs) that measure +8 and −12 kV/ $\mu $ s.