Advanced Analogic Technologies (AnalogicTech) has introduced a integrated battery charger IC designed to operate from USB port inputs. The AAT3688 features a charge reduction loop that reduces charge time by automatically monitoring the USB port voltage and dynamically adjusting the current while the battery is charging. The function simplifies this task, allowing users to charge faster and more efficiently from the USB port by automatically adjusting for voltage sags and reducing the charge current as other functions on the host device consume more power.

The device integrates a charging device, reverse blocking diode, and current sensing circuit in a 3mm x 3mm TDFN package. Covering a 4V to 5.5V input range, the device is designed to regulate voltage and current for 4.2V lithium ion/polymer battery cells. Charge current on the AAT3688 can be programmed for two separate levels, USB High and USB Low, between 50mA and 500mA, depending upon port type.

To ensure safety and system reliability, the AAT3688 offers safety features including the ability to monitor battery temperature and charge state for fault conditions. If an over-voltage or over-temperature failure occurs, the device automatically shuts down to protect the charging device, the control system, and the battery under charge. Status monitor output pins can be used to directly drive two external LEDs to indicate battery status. The AAT3688 also includes a serial interface output that reports any one of 14 status states to a microcontroller.