A Dual-Active-Bridge DC-DC converter IC in 0.18μm, 80V BCD with integrated high-speed digital isolator and high-precision phase-shift control

This work targets the miniaturization of bidirectional isolated dc-dc converters for renewable energy applications with integrated energy storage. A power IC was fabricated in a 0.18μm 80V BCD process to integrate the primary-side low-voltage bridge in Dual-Active-Bridge (DAB) converter. The targeted power level of the converter is 50 W per IC, with a high switching frequency of 1 MHz. A Phase-Locked-Loop (PLL) based synchronization scheme is used to reduce the number of digital isolators to transmit gating pulse. The IC includes the power-stage, drivers, protection features, communication transceivers, PLL synchronization and 12-bit phase-shift module for precise power control. High-frequency isolated communication is demonstrated at 167 MHz using an air-core PCB based transformer. The soft-switching converter achieves a peak efficiency of 94% at 1 MHz.