A 2MHz 4-48V $\mathrm{V}_{\text{IN}}$ Flying-Capacitor Based Floating-Ground GaN DC-DC Converter with Real-Time Inductor Peak-Current Detection and $6\mu \mathrm{s}$ Load Transient Response

This paper presents a 2MHz 4V-to-48V VIN, GaN-based buck-boost converter with optimized buck-boost mode, enhanced safe protection, and fast transient response for automotive Advanced Driving Assistant Systems (ADAS). A flying-capacitor-based floating-ground topology is proposed first time to solve the issue associated with extremely short on time, improve power efficiency in the buck-boost region and provide real-time detection and management of the inductor peak current. This floating-ground technique helps alleviate the problem of efficiency drop in the four-switch buck-boost topology and ensures converter/load safety. An indirect current sensor is also proposed, which allows for sensing the inductor current change in the buck-boost mode without using any bulky sensing resistors and achieves $k$ fast transient response with 100mv-undershoot/80mV-overshoot for 1A load current change. This converter achieves a maximum efficiency of 92% which is comparable to the state-of-the-art buck-boost schemes