BQ2040_15 Datasheet, PDF (1/36 Pages) Texas Instruments – Gas Gauge IC With SMBus Interface

Not Recommended For New Designs
bq2040
Gas Gauge IC With SMBus Interface
Features
® Provides accurate measurement
of available charge in NiCd,
NiMH, and Li-Ion batteries
® Supports SBS v1.0 data set and
two-wire interface
® Monitors charge FET in Li-Ion
pack protection circuit
® Designed for battery pack inte-
gration
- Low operating current
- Complete circuit can fit on less
than ¾ square inch of PCB
space
® Supports SBS charge control
commands for NiCd, NiMH, and
Li-Ion
® Drives a four-segment LED dis-
play for remaining capacity
indication
® 16-pin narrow SOIC
General Description
The bq2040 Gas Gauge IC With
SMBus Interface is intended for
battery-pack or in-system installa-
tion to maintain an accurate record
of available battery charge. The
bq2040 directly supports capacity
monitoring for NiCd, NiMH, and Li-
Ion battery chemistries.
The bq2040 uses the System Man-
agement Bus v1.0 (SMBus) protocol
and supports the Smart Battery
Data (SBData) commands. The
bq2040 also supports the SBData
charge control functions. Battery
state-of-charge, remaining capacity,
remaining 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 bq2040 estimates battery self-
discharge based on an internal
timer and temperature sensor and
user-programmable rate informa-
tion stored in external EEPROM.
The bq2040 also automatically re-
calibrates or “learns” battery capac-
ity in the full course of a discharge
cycle from full to empty.
The bq2040 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
VCC for other battery cell configu-
rations.
An external EEPROM is used to
program initial values into the
bq2040 and is necessary for proper
operation.
Pin Connections
VCC
1
ESCL
2
ESDA
3
LED1
4
LED2
5
LED3
6
LED4
7
VSS
8
16
VOUT
15
REF
14
SMBC
13
SMBD
12
PSTAT
11
SB
10
DISP
9
SR
16-Pin Narrow SOIC
PN204001.eps
SLUS005–JUNE 1999 E
Pin Names
V_CC
ESCL
3.0–6.5V
EEPROM clock
ESDA EEPROM data
LED_1-4 LED segment 1-4
V_SS
System ground
SR
Sense resistor input
DISP Display control input
1
SB
Battery sense input
PSTAT Protector status input
SMBD SMBus data input/output
SMBC SMBus clock
REF Voltage reference output
V_OUT EEPROM supply output