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Industry's Smallest, Stand-Alone, Multicell Li+ Battery Fuel Gauge to Integrate LED Drivers and a Pushbutton Input

Stand-Alone Battery Fuel Gauge Integrates LED Drivers and Pushbutton Input

Note to Editor: The DS2788 is a stand-alone fuel gauge IC with integrated LED display drivers and a pushbutton input. Offering the industry's smallest solution, the DS2788 saves both space and cost. The DS2788 enables the industry's smallest solution by integrating multiple dedicated LED drivers and a pushbutton input into a 14-pin TSSOP package. Capable of directly sinking current, the LED driver pins only require a resistor to set the LED display current, further reducing space and cost. The DS2788 is ideal for power tools, ebikes, portable household appliances, ultra-mobile PCs, or any application that benefits from an LED display that shows the remaining battery capacity.

SUNNYVALE, CA—February 18, 2008—Maxim Integrated Products (Pink Sheets: MXIM) introduces the DS2788, the industry's smallest stand-alone fuel gauge to integrate LED drivers and a pushbutton input for multiple Li+ cells into a single IC. Designed for the tight space of a battery pack, it is packaged in a lead-free 14-pin TSSOP. The DS2788 is ideal for displaying the remaining battery capacity of power tools, ebikes, portable household appliances, and ultra-mobile PCs.

The DS2788 reports a battery pack's remaining capacity in both "mAh remaining" and "percentage of full" to the host system, and it displays the results using either four or all five of its integrated LED driver outputs. Capable of directly sinking current, each LED driver pin requires only a single resistor to set its current in the LED display, thus reducing board space and system cost. A programmable I/O pin that can be configured as a debounced-pushbutton input enables the LED display.

To reduce the need for software development and shorten time-to-market, the DS2788 utilizes an embedded fuel gauge algorithm to calculate remaining capacity based on precision coulomb count, discharge rate, temperature, and cell characteristics, along with precision battery-current and voltage measurements. The fuel gauge accurately monitors battery packs with multiple Li+ cells by allowing internal gain calibration of an external voltage-divider that feeds the battery-voltage-measurement input. To conserve battery power, a pin for driving external FET switches enables the voltage-divider only during voltage measurement. An estimate of the battery pack's capacity is communicated to the host over a 1-Wire® interface, which reduces the number of necessary contacts between the pack and the host to as few as three.

Additionally, the DS2788 provides 16 bytes of EEPROM for the exclusive use of the host system and/or pack manufacturer. This EEPROM can be used to facilitate battery lot and date tracking, as well as for the nonvolatile storage of system or battery-usage statistics. A unique, factory-programmed 64-bit ROM ID assures that no two DS2788s are alike and enables absolute battery-pack traceability.

Prices start at $2.72 (1000-up, FOB USA).

Maxim Integrated Products, a two billion dollar company, designs and manufactures ICs for analog and mixed-signal applications. The company's broad portfolio of 27 product categories is among the industry's deepest, with over 5400 products.