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NEW PRODUCT NEWS—edited by Harv Weiner

Smart Battery Monitor

The DS2438 stores battery-specific data and tracks battery parameters, including temperature, voltage, current, and remaining charge. It makes battery management cost-effective for portable products by providing battery data and measurements (which must be done in the pack) to the host system's processor, where charge-control and remaining-charge algorithms are executed in software.

A 1-Wire network enables the pack-resident DS2438 to communicate with portable products over a single wire. With this network, products and battery packs can connect using three electrical contacts (power, ground, and data), minimizing connector cost and maximizing reliability. The DS2438 gives its battery pack a unique 64-bit net address, allowing multiple battery packs to be wired to a single bus but addressed individually. So, products can connect more batteries simultaneously, supporting dual-battery operation.

The DS2438 provides 40 bytes of nonvolatile EEPROM memory. A portable product can read this memory over the 1-Wire network to identify the chemistry, capacity, and construction of the battery pack and configure itself for that particular battery. Because the memory can be rewritten, frequently changing data can be stored inside the battery pack. EEPROM memory still maintains stored data when the battery is discharged or momentarily short-circuited.

The DS2438 provides a complete set of battery instrumentation. It measures battery temperature with 0.03ęC resolution, battery voltage with 10-mV resolution, and battery current with 10-bit resolution. It integrates current over time to facilitate fuel gauging. A built-in offset-cancellation feature improves current measurement accuracy. The data is available to the portable product for charge-control, remaining-charge estimation, and other battery monitoring tasks.

The DS2438 costs $1.15 in 10k volumes. And, a DS2438K evaluation kit is available.

Dallas Semiconductor
(972) 371-4448
www.dalsemi.com

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