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
- 120µA typical operating
current
- Small size enables
implementations in as little as
3
4
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. Battery state-of-
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.
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
VCC 3.0–5.5V
SCL Serial memory
clock
SDA Serial memory
data
SEG1 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
V
OUT
REF
SCC
SCD
NC
SB
DISP
SR
V
CC
SCL
SDA
SEG
1
SEG
2
SEG
3
SEG
4
V
SS
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