Design of Adaptive On-Time GaN DC-DC Converter with Active Gate Driving for Automotive System

Abstract

The proposed paper introduces a single-stage Gallium Nitride (GaN) DC-DC converter employing adaptive on-time (AOT) hysteresis control including an active gate driving bootstrap (BST) gate driver. To achieve optimal one-cycle transient response during load variations, it incorporates a sample and hold-based load detecting transient enhancer for precise detection of load changes and accurate control of on-time extension. Additionally, an active gate driver utilizing a dv/dt detector is designed and applied to independently control dv/dt and di/dt, mitigating the trade-off between electromagnetic interference (EMI) and switching loss. The converter was fabricated using a 0.18-µm HV BCD 1P6M process with a total chip area of 1.05 × 0.80 mm. It converts up to 60-V input down to 3-V and operates in the frequency range of 0.95–9.5 MHz. Designed to support a wide automotive battery voltage range from 7 to 60 V, post-layout simulations show the output voltage ripple is as low as 2.9 mV at 12 to 3 V conversion and 4.2 MHz switching frequency, achieving a maximum efficiency of 91.3%.