Power device design for a hybrid actuator

There is an increasing demand for high current actuators with integral fault diagnosis. These can be produced using monolithic intelligent MOS based structures or by using a multichip hybrid. The authors describe an example of a two chip hybrid, high-sided, power actuator for 5 to 6 A DC current handling capability at 0.25 V saturation. The two chips comprise an analogue controller and power driver. The controller provides output, status, electrical and thermal protection and control functions. The power device is based on a high gain, low voltage planar PNP, with additional features incorporated for reducing the power dissipation of the linear controller and also for sensing thermal overdissipation. These features are included to improve the protection, feedback and reliability of the hybrid. The authors emphasise the special requirements of the power output function of the actuator