An Ultra-Fast Overcurrent Protection Circuit Based on SMD Shunt Resistors for Wide Band-Gap Devices

Since a sudden increase in drain current is a clear indicator of a short-circuit in a power device, SC protection systems based on a direct current measurement are often the most straightforward and efficacious solutions. However, when dealing with wide band-gap (WBG) technologies, the limitations of current sensing techniques pose a significant challenge to the design of short circuit (SC) protection, especially for gallium nitride (GaN) power devices. Specifically, in the case of GaN, protection systems based on principles other than current sensing remain a viable option, but the effectiveness of these protection systems is limited by the need for complex circuitry to meet the stringent intervention time requirements. This paper presents a straightforward and fast overcurrent protection (OCP) system based on direct current measurement applied to 650 V E-mode gallium nitride (GaN) high electron mobility transistors (HEMTs). The monitoring of the current is achieved through the use of a surface-mount device (SMD) shunt resistor and a basic passive network. A simple logic mechanism promptly identifies when the current exceeds the predefined overcurrent limit, thereby enabling the automatic shutdown of the device under test (DUT). As it is based on current monitoring, this system can protect the device from both overcurrent and SC conditions. Consequently, there is no longer a need to build two different systems to perform these functions. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.