BQ2014_15 Datasheet, PDF (3/27 Pages) Texas Instruments – Gas Gauge IC with External Charge Control

Not Recommended For New Designs
bq2014
Functional Description
General Operation
The bq2014 determines battery capacity by monitoring
the amount of charge input to or removed from a re-
chargeable battery. The bq2014 measures discharge and
charge currents, estimates self-discharge, monitors the
battery for low-battery voltage thresholds, and compen-
sates for temperature and charge/discharge rates. The
charge measurement is made by monitoring the voltage
across a small-value series sense resistor between the
battery’s negative terminal and ground. The available
battery charge is determined by monitoring this voltage
over time and correcting the measurement for the envi-
ronmental and operating conditions.
Figure 1 shows a typical battery pack application of the
bq2014 using the LED display capability as a charge-
state indicator. The bq2014 is configured to display ca-
pacity in a relative display mode. The relative display
mode uses the last measured discharge capacity of the
battery as the battery “full” reference. The LED seg-
ments output a percentage of the available charge based
on NAC and LMD. A push-button display feature is
available for momentarily enabling the LED display.
The bq2014 monitors the charge and discharge currents
as a voltage across a sense resistor (see RS in Figure 1).
A filter between the negative battery terminal and the
SR pin is required.
Figure 1. Battery Pack Application Diagram—LED Display,
3