Product category:
Analogue and Mixed Signal ICs
News Release from: Maxim Integrated Products | Subject: DS2788
Edited by the Electronicstalk Editorial
Team on 19 February 2008
Li-ion fuel gauge drives its own display
The DS2788 is ideal for displaying the remaining battery capacity of power tools, e-bikes, portable household appliances and ultramobile PCs.
Maxim Integrated Products describes the DS2788 as the industry's smallest stand-alone fuel gauge to integrate LED drivers and a pushbutton input for multiple Li-ion cells into a single IC Designed for the tight space of a battery pack, it is packaged in a lead-free 14-pin TSSOP
This article was originally published on Electronicstalk on 27 Aug 2002 at 8.00am (UK)
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The DS2788 is ideal for displaying the remaining battery capacity of power tools, e-bikes, portable household appliances and ultramobile PCs.
The DS2788 reports a battery pack's remaining capacity in both "milliampere-hours 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 uses 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-ion 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 16byte 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 64bit ROM ID assures that no two DS2788s are alike and enables absolute battery-pack traceability.
Prices start at US $2.72 (1000-off).
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