Parasitic Capacitances Characterization of Double-Sided Cooling Power Module Based on GaN Devices

The parasitic capacitances of a novel double-sided cooling structure of GaN power module are analyzed in this paper. Due to the additional top ceramic substrate of the structure, parasitic capacitances become more complex. By analysis, gate-source parasitic capacitance and gate-drain parasitic capacitance of all GaN devices and drain-source parasitic capacitance of upper GaN device of half bridge circuit are less than 1% of the corresponding intrinsic capacitances. However, the drain-source parasitic capacitance (14% of C_oss) of bottom GaN device of half bridge circuit increases by 30% compared with traditional single-sided cooling module, which is acceptable since the thermal resistance of this structure is about halved.