bq2011

The bq2011 Gas Gauge IC is intended for battery-pack installation to maintain an accurate record of available battery charge. The IC monitors a voltage drop across a sense resistor connected in series between the negative battery terminal and ground to determine charge and discharge ac-tivity of the battery. The bq2011 is designed for systems such as power toolswithveryhighdischargerates.


Battery self-discharge of bq2011 is estimated based on an internal timer and tem-perature sensor. Compensations for battery temperature and rate of charge or discharge are applied to the charge, discharge, and selfdischarge calculations to provide available charge information across a wide range of  perating conditions.Initial battery capacity is set using the PFC and MODE pins. Actualbattery capacity is automatically"learned" in the course of a discharge cycle from full to empty and may be displayed depending on the displaymode.


Nominal available charge may be directly indicated using a five-seg-ment LED display. These segments are used to indicate graphically the nominalavailablecharge.


The bq2011 supports a simple singleline bidirectional serial link to an external processor (common ground). Thebq2011 outputs battery information in response to external commands over the serial link. To support subassembly testing, the outputs may also be controlled by command.The external processor may also overwrite some of the bq2011gasgaugedataregisters.


The bq2011 may operate directly from four cells. With the REF output and an external transistor, a simple, inexpensive regulator can be built to provide V_CC from a greater number ofcells.


Internal registers of bq2011 include available charge, temperature, capacity, battery ID,andbatterystatus.