Application of 40 KW Power Darlington Transistors in Large DC to DC Converters and Motor Speed Control

General Electric Company has developed the D67D (a high speed darlington) power transistor rated at 400 Volts (sustaining) and collector currents of 100 Amps continuous (160 Amps peak). The devices are monolithic and utilize a new power package which is available in the isolated (R¿JC = .4°C/W max.) and non-isolated (R¿JC = .25°C/W max.) collector configurations. Some typical applications for the device would be for motor control and switching power supplies. Some design considerations are detailed which show the D67D as the power switch for a (1) push-pull output stage, (2) buck converter, and (3) inverter for a 10 H.P. induction motor.