bq2011K

The bq2011K Gas Gauge IC is intended for battery-pack installation to maintain an accurate record of a battery's available 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 bq2011K is designed for systems such as power toolswithveryhighdischargerates.


Battery self-discharge of bq2011K is estimated based on an internal timer and temperature 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 operating conditions.Initial battery capacity is set using the PROG1-4 and SPFC pins. Actual battery 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 of bq2011K may be directly indicated using a five-seg-ment LED display. These segments are used to graphically indicate nominalavailablecharge.


The bq2011K supports a simple single-line bidirectional serial link to an external processor (common ground). The bq2011K outputs bat-tery 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 bq2011Kgasgaugedataregisters.


The bq2011K 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 numberofcells.


Internal registers of bq2011K include available charge, temperature, capacity, battery ID,andbatterystatus.