BQ2092_15 Datasheet, PDF (3/30 Pages) Texas Instruments – Gas Gauge IC with SMBus-Like Interface

Obsolete Device
bq2092
Functional Description
General Operation
The bq2092 determines battery capacity by monitoring
the amount of charge input to or removed from a
rechargeable battery. The bq2092 measures discharge
and charge currents, estimates self-discharge, and
monitors the battery for low-battery voltage thresh-
olds. The charge measurement is made by monitoring
the voltage across a small-value series sense resistor
between the battery's negative terminal and ground.
The available battery charge is determined by moni-
toring this voltage over time and correcting the meas-
urement for the environmental and operating condi-
tions.
Figure 1 shows a typical battery pack application of the
bq2092 using the LED capacity display, the serial port,
and an external EEPROM for battery pack program-
ming information. The bq2092 must be configured and
calibrated for the battery-specific information to ensure
proper operation. Table 1 outlines the externally
programmable functions available in the bq2092. Refer
to the Programming the bq2092 section for further
details.
An internal temperature sensor eliminates the need
for an external thermistor—reducing cost and compo-
nents. An internal, temperature-compensated time-
base eliminates the need for an external resonator,
further reducing cost and components. The entire
circuit
in
Figure
1
can
occupy
less
than
3
4
square
inch
of board space.
VCC
SCL
VOUT
REF
SDA ^SCC
SEG1
SCD
NC
SEG2 _SB
SEG3 _DISP
SEG4 _SR
BZX84C5V6
BZX84C5V6
2192L.eps
Figure 1. Battery Pack Application Diagram—LED Display
3