Dallas Semiconductors’ Battery Charger Touts Extra Measure of Safety

Dallas Semiconductor Corp. introduced its DS2714 – a loose-cell charger IC specifically for functioning NiMH and NiCd batteries; it shuts down on detecting primary alkaline cells, lithium primary cells and defective NiMH or NiCd cells. Designed to work with a regulated charge source, the DS2714 can charge from one to four NiMH or NiCd battery cells (including AA or AAA sizes) for digital still cameras, portable music players, and portable electronic games and toys.

The DS2714 first conducts a precharge qualification test that prevents the fast charging of deeply depleted cells or damaged cells. Deeply depleted cells are charged at a reduced rate to protect them from damage and to extend the life of the battery until fast charging can commence. During the fast-charge phase, the DS2714 continues to check for inappropriate or damaged cells. Fast-charging terminates with the negative-delta-V or flat-V method, followed by a top-off phase. Finally, a maintenance phase continues indefinitely to keep the cells fully charged. Throughout, the chip continuously monitors cell voltage and temperature to ensure they're within proper range. The DS2714 includes an adjustable timer for increased safety and secondary termination. Four LED outputs provide the drive for displaying charge status and fault conditions.

The DS2714, in a 20-pin TSSOP package, is priced starting at $1.99 each (1,000-up, FOB USA).