Electrical engineering

Physics

Chip

Rectification

Electronic circuit

Engineering

Power semiconductor device

Voltage

Junction temperature

Composite material

Power (physics)

Gate driver

Materials science

Electronic engineering

Gallium nitride

Layer (electronics)

Integrated circuit

Quantum mechanics

Optoelectronics

IEEE Journal of Solid-State Circuits

To unlock the full potential of monolithic gallium nitride (GaN) power integrated circuits, this article explores the feasibility of developing efficient and reliable on-chip gate driving and level shifting solutions, which fundamentally facilitate the on-chip implementation of GaN power circuits. As results, a self-bootstrapped hybrid (SBH) gate driving scheme and its circuitry are developed, which achieve rail-to-rail dynamic gate driving in normal operation and robust static gate driving in large transient moments. Meanwhile, an auto-lock auto-break (A2) level shifting technique is proposed to convert the gate driving control signals from low-voltage (LV) to high-voltage (HV) domains, without requiring any p-type devices. This enables the on-chip operation of high-side power switches and makes synchronous rectification possible. On-chip temperature sensing is implemented to monitor junction temperature directly at low circuit complexity and power and cost overheads, facilitating thermal protection at high power density. Furthermore, on-die dead-time control is presented to optimize zero voltage switching (ZVS) for high efficiency. All the techniques and circuits are demonstrated in a monolithic asymmetrical half-bridge (AHB) power converter on a GaN-on-SOI process. It achieves direct 48V/1V dc–dc conversion with a maximum load current of 5 A and a current density of 1.1 A/mm2. Among the existing monolithic GaN power ICs capable of on-chip synchronous rectification, it achieves the shortest rising- and falling-edge gate driving delays of 11.6 and 14.0 ns. Despite running doubled numbers of on-chip power transistors and gate drivers, it only consumes 70-mW static power.

A Monolithic GaN Power IC With On-Chip Gate Driving, Level Shifting, and Temperature Sensing, Achieving Direct 48-V/1-V DC–DC Conversion