Features

ä Complete bq2011 Gas Gauge solution for NiCd

packs in high discharge rate applications

ä Five surface-mounted LEDs to display

state-of-charge information

ä Battery state-of-charge monitoring for 4- to 12-cell

series applications

ä On-board regulator allows direct connection to the

battery

ä Battery information available over a single-wire

bidirectional serial port

ä Nominal capacity pre-configured

ä 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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