
Features
Provides accurate measure-
ment of available charge in
NiCd, NiMH, and Li-Ion re-
chargeable batteries
Supports SBData charge con-
trol commands for Li-Ion,
NiMH, and NiCd chemistries
Designed for battery pack inte-
gration
-
120
μ
A typical operating
current
-
Small size enables
implementations in as little as
34
square inch of PCB
Two-wire SMBus-like interface
Measurements compensated for
current and temperature
Programmable self-discharge
and charge compensation
16-pin narrow SOIC
General Description
The bq2092 Gas Gauge IC With
SMBus-Like Interface is intended
for battery-pack or in-system instal-
lation to maintain an accurate
record of available battery charge.
The bq2092 directly supports capac-
ity monitoring for NiCd, NiMH, and
Li-Ion battery chemistries.
The bq2092 uses the SMBus proto-
col that supports many of the Smart
Battery Data (SBData) commands.
The bq2092 also supports SBData
charge control.
charge, capacity remaining, remain-
ing time and chemistry are available
over the serial link. Battery-charge
state can be directly indicated using
a four-segment LED display to
graphically depict battery full-to-
empty in 25% increments.
Battery state-of-
The bq2092 estimates battery self-
discharge based on an internal
timer and temperature sensor and
user-programmable rate informa-
tion stored in external EEPROM.
The bq2092 also automatically
recalibrates or “learns” battery
capacity in the full course of a
discharge cycle from full to empty.
The bq2092 may operate directly
from three nickel chemistry cells.
With the REF output and an exter-
nal transistor, a simple, inexpensive
regulator can be built to provide V
CC
for other battery cell configurations.
An external EEPROM is used to
program initial values into the
bq2092 and is necessary for proper
operation.
1
bq2092
Gas Gauge IC with SMBus-Like Interface
V
CC
3.0–5.5V
SCL
Serial memory
clock
SDA
Serial memory
data
SEG
1
LED segment 1
SEG
2
LED segment 2
SEG
3
LED segment 3
SEG
4
LED segment 4
V
SS
System ground
1
PN209101.eps
16-Pin Narrow SOIC
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VOUT
REF
SCC
SCD
NC
SB
DISP
SR
VCC
SCL
SDA
SEG1
SEG2
SEG3
SEG4
VSS
SR
Sense resistor input
DISP
Display control input
SB
Battery sense input
SCD
Serial communication
data input/output
SCC
Serial communication
clock
REF
Voltage reference
output
V
OUT
EEPROM supply
output
6/99 C
Pin Connections
Pin Names