Date: 13/07/2010

Single and duel cell fuel gauge ICs from Maxim to estimate Li+ battery state of charge

Maxim has introduced the MAX17040/MAX17041 and MAX17043/MAX17044, 1- and 2-cell fuel-gauge ICs. These ICs use the ModelGauge algorithm. Maxim says that these are the industry's only fuel gauges that accurately estimate the state of charge (SOC) of a Li+ battery without requiring current sensing. These ModelGauge ICs eliminate the need for current-sense resistor and require very few external components. These ICs are suggested for handheld 1- and 2-cell Li+ battery applications like wireless handsets, smartphones, e-books, portable game players, digital cameras, handheld computers and financial terminals, portable navigation equipment, and portable medical equipment.

Some of the features of these fuel-gauge ICs are:
1. The recent designs implement the fuel-gauging function on the system side rather than inside the battery like in traditional systems thus reducing cost of the application.
2. Uses ModelGauge technology to overcome the limitations of voltage-only-based fuel gauging.
3. These ICs have a sophisticated battery-modeling scheme that provides high accuracy with very few external components.
4. These ICs track the battery's relative SOC continuously over a widely varying charge/discharge usage profile.
5. These ICs do not require current measurement and they estimate battery state using voltage measurement alone. Therefore, they do not need a current-sense resistor.
6. These ICs also eliminate several other discrete components and the coulomb counter, which according to Maxim results in an overall cost savings of 30% to 50% compared to traditional approaches.
7. These ICs do not have any problem with offset drift and also eliminate the need for battery "relearn cycles."
8. These ICs are shipped with factory calibration.
9. These fuel gauges use the use a supply current of 50µA (typ).
10. They require only two or three resistors and two capacitors.
11. The MAX17040/MAX17043's measurement and power-supply inputs connect directly to the battery pack.
12. The MAX17041/MAX17044's measurement inputs connect directly to the battery pack and can be powered by 3.3V system power.
13. The MAX17043/MAX17044 have a programmable low-battery alert to warn the system microcontroller to take appropriate power-management actions when the battery is nearly empty.

Package: lead-free 8-pin, 2mm x 3mm TDFN.

Price: Start at US$0.89 for MAX17040, US$0.95 for MAX17041, US$0.99 for MAX17043, and US$1.01 for MAX17044.

Availability: Now

For more information visit: www.maxim-ic.com/ModelGauge-ICs