High efficiency automotive power supply with hysteretic current mode controller

A switched mode power supply for an automotive power control module with a novel hysteretic current mode control (HCMC) controller is presented. The HCMC operation principle is described and a method of reducing switching frequency variation is analyzed. Experimental results and critical waveforms of the power switching regulator are shown. Several monitoring and indication functions are designed into the controller to interface with the rest of the system. The controller includes a linear regulator to provide power for memory registers while the system is in the "key-off" state.