Features
➤
Complete and compact lithium ion gas gauge and
protection solution for three or four series cells
➤
Accurate measurement of available battery
capacity
➤
Provides overvoltage, undervoltage, and
overcurrent protection
➤
Designed for battery pack integration
–
Small size
–
Includes bq2050 and bq2058 ICs
–
On-board charge and discharge control FETs
–
Low operating current for minimal battery drain
➤ High side FET control
➤ Battery capacity available through single-wire
serial port
➤ “L” version includes 5 push-button activated LEDs
to display state-of-charge information
General Description
The bq2167 Power Gauge Module provides a complete and
compact battery management solution for Li-Ion battery
packs. Designed for battery pack integration, the bq2167
combines the bq2050 Power Gauge IC with the bq2058 Su
-
pervisor IC on a small printed circuit board. The board in
cludes all the necessary components to accurately monitor
battery capacity and protect the cells from overvoltage, un
dervoltage, and overcurrent conditions. The board works
with three or four Li-Ion series cells.
The Power Gauge IC uses the on-board sense resistor to
track charge and discharge activity of the battery pack.
Critical battery information can be accessed through the
serial communications port at DQ. The supervisor cir
cuit consists of the bq2058 and two FETs. The bq2058
controls the FETs to protect the batteries during
charge/discharge cycles and short circuit conditions. The
bq2167 provides contacts for the positive and negative
terminals of each battery in the stack. Please refer to
the bq2050 and bq2058 data sheets for the specifics on
the operation of the power gauge and supervisor ICs.
Unitrode configures the bq2167 based on the informa
tion requested in Table 1. The configuration defines the
number of series cells, the nominal battery pack capac
ity, the self-discharge rate, the Li-Ion battery type (coke
or graphite anode), and the threshold limits. Figure 1
shows how the module connects to the cells.
The bq2167L includes five LEDs to display remaining capacity in 20% increments of the learned capacity. The LEDs are
activated with the onboard push-button switch.
A module development kit is also available for the
bq2167. The bq2167B-KT or the bq2167LB-KT includes
one configured module and the following:
1) An interface board that allows connection to the
serial port of any AT-compatible computer.
2) Menu driven software to display charge/discharge
activity and to allow user interface to the bq2050
from any standard DOS PC.
Pin Descriptions
POS
Pack positive
B1P
BAT
1P
/Battery 1 positive input
B1N
BAT
1N
/Battery 1 negative input
B2N
BAT
2N
/Battery 2 negative input
B3N
BAT
3N
/Battery 3 negative input
B4N
BAT
4N
/Battery 4 negative input
ITEST
Overcurrent test input
DQ
Serial communications port
NEG
Pack negative
1
bq2167
5/99 B
Li-Ion Power Gauge™ Module
with Pack Supervisor