Linear Single Cell Li-Ion Battery Charger IC with Dual Input Supply

The RT9502 is a fully integrated low cost single-cell Li-Ion battery charger IC ideal for portable applications. The RT9502 is capable of being powered up from AC adapter and USB (Universal Serial Bus) port inputs. The RT9502 can automatically detect and select the AC adapter and the USB port as the power source for the charger. The RT9502 enters sleep mode when both supplies are removed.
The RT9502 optimizes the charging task by using a control algorithm including precondition mode, fast charge mode and constant voltage mode. The charging task is terminated as the charge current drops below the preset threshold. The USB charge current can be selected from preset ratings of 100mA and 500mA, while the AC adapter charge current can be programmed up to 1A with an external resister. The internal thermal feedback circuitry regulates the die temperature to optimize the charge rate for all ambient temperatures.
The RT9502 features 18V and 7V maximum rating voltages for AC adapter and USB port inputs respectively. The other features are under voltage protection, over voltage protection for AC adapter supply and battery temperature monitoring.