Simulating a BJT-MOSFET cascode-connected power switch suitable for resonant converters

A cascode connection of a high-voltage bipolar transistor and a low-voltage MOSFET is modeled and simulated using PC-based SPICE software. A simple representation for the reverse recovery phenomena in the bipolar power transistor, which compensates the incompleteness of the PSPICE model is described. The effect of ferromagnetic hysteresis in the base drive transformer has been taken into account. Comparison of simulations with experimental results is provided. The use of this combinational switch is demonstrated in a 30 W class-E inverter breadboard operating at 270 kHz from a DC input voltage up to 310 V. The switch is capable of holding off voltages beyond 1500 V.<>