The SMB329 and SMB339 are programmable single-cell lithium-ion/lithiumpolymer battery chargers designed for a variety of portable applications. The devices provide a simple and efficient way to charge high-capacity LiIon batteries via a USB or AC adapter input. Furthermore, the SMB329 and SMB339 are able to automatically adjust input current level by detecting the AC/DC adapter's maximum stable output current, thereby automatically matching wall adapter to electronic device. Unlike conventional devices, the SMB329's and SMB339's high-efficiency, switch-mode operation eliminates the thermal problems of conventional linear solutions. Also the buck converter architecture effectively multiplies the input current to increase charge rate for the Li+ cell and uses current limited supplies like USB more efficiently. A 50mA SYSON switch output provides a bypass power supply to boot the system for "instant on" without waiting for charging in case of a dead battery (SMB329 only). Both products also support USB On-the-Go devices by providing the required USB-OTG +5V power supply using the Li-Ion battery as a source. The SMB329 and SMB339 can switch between USB mode and AC Adapter mode and work seamlessly in conjunction with a USB controller. Furthermore, they offer the option to automatically differentiate an AC/DC wall adapter from a USB2.0 hub via the D+/D- USB lines, making them compatible with USB battery charging specification 1.0. Charge control includes qualification, trickle-charge, pre-charge, constant current/constant voltage, float voltage and termination/safety settings that are fully programmable via a serial I2C/SMBus, making the devices truly a flexible solution. Fast charge current level can be set via I2C (limited in USB mode to ensure 100mA or 500mA input). Built-in is reverse-current blocking to prevent inadvertent cell discharge. The SMB329 and SMB339 offer the option to automatically charge the battery only when the battery voltage is below a selectable "dead-battery" threshold. High-frequency operation and integrated power FETs contribute to a reduced external component count and size.