The SMB138 is a programmable single-cell lithium-ion/lithium-polymer battery charger designed for a variety of portable applications. The device provides a simple and efficient way to charge high-capacity LiIon batteries via a USB or AC adapter input. Unlike conventional devices, the SMB138'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. The SMB138 also supports USB On-the-Go devices by providing the required USB-OTG +5V power supply using the Li-Ion battery as a source.