Integrated High-Speed Over-Current Protection Circuit for GaN Power Transistors

In this work, a new desaturation-based over-current protection circuit is proposed and monolithically integrated with GaN power HEMTs. Compared to traditional desaturation techniques, this new design features separated sensing branch and blanking time controller. Such a separation allows immediate sensing of over-current (OC) event, while the blanking time can be modified without considering the sensing speed. To mimic real situations in power applications, the circuit was systematically characterized under different operating conditions. It can deliver an accurate OC threshold voltage and fast response without affecting the switching characteristics. These properties will contribute to a more robust and reliable high-speed GaN power systems.