Energy Efficient PWM Controllers

This paper describes the development of two integrated circuits (ICs) designed to provide pulse width modulation (PWM) control of direct current permanent magnet (DCPM) motors such as those used in automotive vehicles. One of the ICs is for low side driving of the load. The other IC is for high side driving of the load. The development of these ICs was undertaken because of the growing problem of providing adequate electrical power for the ever-increasing electrical loads in today's and tomorrow's automobiles.. Calculations, lab tests and vehicle applications indicate increases of vehicle electrical power efficiencies were achieved. This paper contains the rationale for development of the ICs, a brief definition of PWM application and the control methods, a description of the control systems and a discussion of the IC architecture. Each IC contains most of the functions required for the PWM control tasks including the system oscillator, voltage regulation, driver output circuit, and load current monitoring. For the high side driver IC a charge pump control circuit is also included. With the IC, and a few external components, control and protection of the MOSFET power control circuit and the load is achieved.