SMB329B: Programmable Switch-mode, Li+ Battery Charger with TurboCharge™ Mode, USB “On- the-Go” Power, USB Power Source Detection and Automatic Input Current Limiting

The SMB329B 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 Li-Ion batteries via a USB or AC adapter input. Furthermore, the SMB329B is 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 SMB329B’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. The SMB329B product also supports USB On- the-Go devices by providing the required USB-OTG +5V power supply using the Li-Ion battery as a source.

The SMB329B can switch between USB mode and AC Adapter mode and work seamlessly in conjunction with a USB controller. Furthermore, it offers the option to automatically differentiate an AC/DC wall adapter from a USB2.0 hub via the D+/D- USB lines, making the device compatible with USB battery charging specification 1.0.