A practical model of the cascode switching process

Cascode circuits are useful for the control of high-voltage wide-bandgap switches, but their switching behaviour is complex. This paper details a practical model of cascode switching to allow the capabilities of HV depletion-mode wide-bandgap devices to be fully exploited. Simple equations that govern each stage of the switching process are derived, giving rise to expressions for key performance parameters. The equations are validated with a SPICE model and are shown to be a useful tool for cascode design and operation. The implications of the equations in practical applications also are discussed.