The AAT3783 precisely regulates battery charge voltage and current for 4.2V Li-Ion/Polymer battery cells through an extremely low RDS(ON) switch. When charged from an adapter or a USB port, the battery charging current can be set by an external resistor up to 1A. In the case of an over-voltage condition in excess of 6.5V, a series switch opens preventing damage to the battery and charging circuitry. With the addition of an external resistor the OVP trip point can be programmed to a level other than the factory set value of 6.5V. In the case of an OVP condition a fault flag is activated. Battery charge state is continuously monitored for fault conditions. In the event of an over-current, battery overvoltage, short-circuit or over-temperature failure, the device will automatically shut down, thus protecting the charging device, control system and the battery under charge. A status monitor output pin is provided to indicate the battery charge status by directly driving an external LED. An open-drain power-source detection output (ADPP) is provided to report the power supply status.