Dv/Dt-control of 1200-V Co-packaged SiC- JFET/GaN-HEMT Cascode Device

A SiC-JFET/GaN-HEMT cascode device is recently proposed, incorporating a low voltage (LV) GaN-HEMT providing normally-off operation and a high-voltage (HV) delivering the HV blocking capability. This cascode device exhibits superior thermal stability and switching speed compared to SiC MOSFETs, but also inevitably presents challenge in dv/dt control as the JFET’s gate cannot be directly controlled by the gate drive. Since dv/dt-control is of great importance to the management and suppression of electromagnetic interference (EMI) in power electronics systems, methods of controlling the dv/dt-rates of SiC/GaN cascode devices need to be developed. In this work, we demonstrated a SiC/GaN cascode device in a highly compact package using flip-chip co-package (FCCP) structure, aiming at minimizing the parasitic influences on its performance evaluation. The dv/dt-control method based on RCD-control (i.e. resistor-capacitor-diode control) is proposed and verified through experimental results using the demonstrated FCCP cascode device. The RCD control method is verified to be more effective compared to other more conventional methods regarding to the transient behavior and gate-driver losses, owing to its balanced control of the turn-on/off dv/dt-rates.