I am trying to implement a circuit in SimPowerSystems, where I'm using a PNP transistor as a comparator (comparing voltages at its base and emitter). When it turns on, it turns on an NPN transistor which is used as a switch. I understand the switch can be implemented with an IGBT (where I feed the signal to turn on the switch, to the gate of the IGBT). But is there some way I can implement the PNP BJT used as a comparator? Are there any other ways to implement a comparator in SimPowerSystems?