National Semiconductor Intros LM3655 Battery Protection IC

National Semiconductor Corp. (Santa Clara, CA) introduced a charge control and protection circuit for embedded lithium-ion and lithium-polymer batteries, the LM3655, which is suitable for embedded battery-powered systems, including smart battery packs, cellular phones, digital still cameras, MP3 players, personal digital assistants, Bluetooth wireless technology headsets and hand-held instrumentation. The LM3655 battery protection IC offers extensive battery over-voltage and over-current protection, battery pre-conditioning, and 1% charger voltage accuracy.

The LM3655 provides complete charge control, discharge control and the battery safety of a single kithium-ion cell. It supports battery charging by using a variety of power supply types, including unregulated current-limited wall adapters, regulated wall adapters and vehicle power adapters. Charge current control is achieved using an external bipolar PNP power transistor.

The LM3655 provides effective and comprehensive discharge control functionality. The operating load current is supplied by the lithium-ion battery and passes through the LM3655, allowing the battery power to disconnect due to overload, short-circuit or low battery conditions. The LM3655 also offers extensive battery safety protection against over-voltage and over-current. The internal safety circuit is backed up by an identical circuit to provide safety redundancy.

The LM3655 requires minimal external components and is packaged in a small micro SMD-25 bump, which measures 2.5 mm x 2.5 mm. Available now and priced in 1,000-unit quantities, the LM3655 is $1.65.