Demonstration circuit DC631 is a complete power solution for a USB powered device. Power is input from one of three sources, and three outputs are provided, as well as supervisory signals for a microprocessor. DC631 provides the following functions; 700mA CC/CV timer terminated charger suitable for 4.2V Li-Ion cells, USB power manager that insures compliance with the USB power specification, two 1.5MHz synchronous step-down converters and reset and power button status outputs for interfacing with a microprocessor.