Simple, Efficient, 1-Cell Li+ Pulse Charger

The MAX1879 single-cell lithium-ion (Li+) battery charger utilizes an efficient pulse-charging architecture to minimize power dissipation in portable devices. This architecture combines the efficiency of switch-mode chargers with the simplicity and low cost of linear chargers. This simple device, in conjunction with a current-limited wall cube and a PMOS transistor, allows safe and fast charging of a single Li+ cell.

The MAX1879 initiates charging in one of three ways: battery insertion, charger power-up, or toggling the THERM pin. Key safety features include continuous voltage and temperature monitoring, a preset charger time-out, and an 8mA precharge current mode to charge near-dead cells. Automatic detection of input power removal shuts down the device, minimizing current drain from the battery. An overall system accuracy of 0.75% ensures that the cell capacity is fully utilized without cycle life degradation.

The MAX1879 is offered in a space-saving 8-pin µMAX® package. An evaluation kit (MAX1879EVKIT) is available to help reduce design time.

Applications

* Cell Phones * Consumer Audio * Cordless Phones * Digital Still Cameras * Global Positioning Systems (GPS) * Pagers * Palmtops, Handy Terminals * Pen Entry Palmtops, PDAs and Organizers * Smart Battery Packs/Chargers

* Simple Design Minimizes Heat

* Low Component Count, No Inductor

* Battery-Full Indicator

* 0.75% Accurate Battery Regulation

* 1.5µA (max) Battery Current Drain with Wall Cube Removed

* Restart Charging at 4.0V

* Continuous Overvoltage and Overtemperature Protection

* Safely Precharges Near-Dead Cells

* Automatic Power-Down when Power Source is Removed

* Charges 1 Cell from as Low as 4.5V

* Pin-Compatible Upgrade to MAX1679