Features
➤
Conservative and repeatable
measurement of available charge
in rechargeable batteries
➤
Designed for battery pack inte
-
gration
-
120µA typical standby current
-
Small size enables implementations in as little as
1
2
square inch of PCB
➤
Integrate within a system or as a
stand-alone device
-
Display capacity via singlewire serial communication
port or direct drive of LEDs
➤ Measurements compensated for
current and temperature
➤ Self-discharge compensation us-
ing internal temperature sensor
➤ Accurate measurements across a
wide range of current (> 500:1)
➤ 16-pin narrow SOIC
General Description
The bq2010 Gas Gauge IC is intended
for battery-pack or in-system installa
tion to maintain an accurate record of
a battery's available charge. The IC
monitors a voltage drop across a
sense resistor connected in series be
tween the negative battery terminal
and ground to determine charge and
discharge activity of the battery.
NiMH and NiCd battery self-dis
charge is estimated based on an inter
nal timer and temperature sensor.
Compensations for battery tempera
ture and rate of charge or discharge
are applied to the charge, discharge,
and self-discharge calculations to pro
vide available charge information
across a wide range of operating conditions. Battery capacity is automatically recalibrated, or “learned,” in the
course of a discharge cycle from full to
empty.
Nominal available charge may be
directly indicated using a five- or
six-segment LED display. These segments are used to indicate graphically the nominal available charge.
The bq2010 supports a simple
single-line bidirectional serial link to
an external processor (common
ground). The bq2010 outputs battery
information in response to external
commands over the serial link.
The bq2010 may operate directly
from 3 or 4 cells. With the REF out
-
put and an external transistor, a sim
ple, inexpensive regulator can be built
to provide V
CC
across a greater
number of cells.
Internal registers include available
charge, temperature, capacity, battery
ID, battery status, and programming
pin settings. To support subassembly
testing, the outputs may also be con
trolled. The external processor may
also overwrite some of the bq2010
gas gauge data registers.
1
LCOM LED common output
SEG
1
/PROG1LED segment 1/
program 1 input
SEG
2
/PROG2LED segment 2/
program 2 input
SEG
3
/PROG3LED segment 3/
program 3 input
SEG
4
/PROG4LED segment 4/
program 4 input
SEG
5
/PROG5LED segment 5/
program 5 input
SEG
6
/PROG6LED segment 6/
program 6 input
1
PN201001.eps
16-Pin Narrow SOIC
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
REF
NC
DQ
EMPTY
SB
DISP
SR
LCOM
SEG1/PROG
1
SEG2/PROG
2
SEG3/PROG
3
SEG4/PROG
4
SEG5/PROG
5
SEG6/PROG
6
V
SS
REF Voltage reference output
NC No connect
DQ Serial communications
input/output
EMPTY Empty battery indicator
output
SB Battery sense input
DISP
Display control input
SR Sense resistor input
V
CC
3.0–6.5V
V
SS
System ground
bq2010
Pin Connections
Pin Names
4/95 D
Gas Gauge IC