All-GaN Integrated Overcurrent Protection Circuit Using Only Enhancement-mode p-GaN Devices

This paper presents the design of a new topology for an Overcurrent Protection (OCP) Integrated Circuit (IC), developed entirely in p-Gallium Nitride (p-GaN) technology using only Enhancement-mode (E-mode) High Electron Transistor Mobility (HEMT) devices. The OCP circuit consists of a current-mirror sensor, a comparator, a latch, and an auxiliary logic circuit. The complexity of this design lies in the absence of P-type devices. To overcome this limitation, Resistor Transistor Logic (RTL) and Push-Pull buffers are employed. The all-GaN OCP circuit was sized to minimise the OCP response time. The GaN power Integrated Circuit (GaN-IC) includes a 650V/10A HEMT operating at 1 MHz. The OCP performance was tested through pre- and post-layout simulation under load and temperature variations. The response time of the OCP, including parasitic extraction is 34 ns for a current limit of 12 A. The OCP-IC demonstrates a 6% faster response time compared to the state-of-the-art.