Power Source Selector Cuts System Cost And Complexity

Designed to reduce both a system's cost and complexity, the MAX1773 power-source selector serves as the control logic for a system with multiple power sources. The device directly drives external P-channel MOSFETs to select from an ac adapter and dual battery sources for charge and discharge. The selection is based on the presence of the power sources and the state of the batteries. Intended for use with a buck-topology charger, the device provides what is said to be a simple and easily controlled solution to a difficult analog power control problem. It provides most of the power source monitoring and selection, freeing the power management microprocessor for other tasks. Available in a 20-pin TSSOP, prices start at $2.82 each/1,000.