RT9511

RT9511 Fully Integrated Battery Charger with Two Step-Down Converters General Description The RT9511 is a fully integrated low cost solution with a single-cell Li-Ion battery charger and two high efficiency step-down DC/DC converters ideal for portable applications. The Battery Charger is capable of being powered up from AC adapter and USB (Universal Serial Bus) port inputs which can automatically detect and select the AC adapter and the USB port as the power source for the charger. The Battery Charger enters sleep mode when both supplies are removed. The Battery Charger optimizes the charging task by using a control algorithm including preconditioning 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 ratings100mA 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 Battery Charger features 18V and 7V maximum rating voltages for AC adapter and USB port inputs respectively. The other features are external programmed safety timer, under voltage protection, over voltage protection for AC adapter supply, battery temperature monitoring and charge status indicator. The high-efficiency step-down DC/DC converter is capable of delivering 1A output current over a wide in...