DALLAS Semiconductor, represented in Australia by Arrow Electronics , has released the DS2782 fuel gauge, using an industry-standard two-wire interface to communicate with the host. It calculates remaining capacity for Li+ and Li± polymer batteries without the need for host-side fuel-gauging algorithms, simplifying software development.
Although it is optimised for single-cell applications it can accommodate multicell applications with a few circuit modifications. Typical applications include digital still cameras, subnotebook computers, handheld PC-data terminals and 3G multimedia wireless handsets.
The DS2782 measures several battery parameters including current, voltage, and temperature. Built-in current-offset correction and user-programmable gain compensation improve current measurement accuracy. The device can be programmed to compensate the current-sense resistor to correct variation in its value over temperature. This enables the use of less accurate, lower cost sense resistors. Voltage measurements are 11-bit with a resolution of 4.88mV over a range of 0V to 4.992V. Temperature measurements are also 11-bits and have a resolution of 0.125°C over the entire -40°C to +85°C Celsius operating range of the device.
Cell characterisation data and application performance parameters used to calculate the remaining battery capacity are stored in 24 bytes of on-chip nonvolatile memory. An additional 16 bytes of nonvolatile memory are available for use by the host system or pack manufacturer.
The DS2782 is available in an eight-pin TSSOP package, small enough to fit on the side of a prismatic battery cell.