Features
c228 Complete bq2011 Gas Gauge solution for NiCd
packs in high discharge rate applications
c228 Five surface-mounted LEDs to display
state-of-charge information
c228 Battery state-of-charge monitoring for 4- to 12-cell
series applications
c228 On-board regulator allows direct connection to the
battery
c228 Battery information available over a single-wire
bidirectional serial port
c228 Nominal capacity pre-configured
c228 Compact size for battery pack integration
General Description
The bq2111L Gas Gauge Module provides a complete
and compact solution for capacity monitoring of NiCd
battery packs in high discharge rate applications such
as power tools. Designed for battery pack integration,
the bq2111L incorporates a bq2011 Gas Gauge IC, five
surface-mounted LEDs, and the other discrete compo-
nents necessary to monitor and display accurately the
capacity of 4- to 12 -series cells. The only external compo-
nent required is a low-value sense resistor connected be-
tween GND and PACK-. Contacts are also provided on
the bq2111L for direct connection to the battery stack
and the serial communications port (DQ). The battery
stack should be connected between BAT+ and GND.
Please refer to the bq2011 data sheet for the specifics on
the operation of the Gas Gauge.
Unitrode configures the bq2111L based on the informa-
tion requested in Table 1. The configuration defines the
number of series cells and the nominal battery pack ca-
pacity. The bq211L module uses the absolute LED dis-
play to indicate battery capacity. In this mode, the
remaining capacity is represented as a percentage of the
programmed capacity.
The bq2111L can operate directly from four series cells
within the pack using the LBAT+ supply input. For four
series cell applications or applications using the on-
board regulator, LBAT+ should be connected to BAT+.
Please refer to Figure 1 for module connection illustra-
tions.
A module development kit is also available for the
bq2111L. The bq2111LB-KT includes one configured
module and the following:
1) An interface board that allows connection to the se-
rial port of an AT-compatible computer.
2) Menu-driven software with the bq2111L to display
charge/discharge activity and to allow user inter-
face to the bq2011 from any standard DOS PC.
3) Source code for the TSR.
Pin Descriptions
P1 DQ/Serial communication port
P2 BAT+/Battery positive/Pack positive
P3 LBAT+/Four--cell power
P4 PACK-/Pack negative
P5 GND/Ground
1
NiCd Gas Gauge Module with LEDs
for High Discharge Rates
bq2111L
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