2.2 Load Voltage Regulator

The switching regulator that converts the 6.4V-8.4V battery voltage into the output 5V supply is an MCP16311 step-down regulator. It is rated for up to 1A of output current and employs a pulse frequency/pulse width modulation operating at 500 kHz. In addition to soft start and Undervoltage Lockout (UVLO), it has a low quiescent current of 44 μA and includes a digital enable input. The design of the regulator is taken directly from the device data sheet, and the enable input is connected to the PIC15224 for disabling the load when the battery is at its minimum charge voltage.