BQ2040 Datasheet, PDF (2/33 Pages) Texas Instruments – Gas Gauge IC With SMBus Interface

bq2040
Pin Descriptions
DISP
VCC
ESCL
ESDA
LED1–
LED4
VSS
SR
Supply voltage input
Serial memory clock
Output used to clock the data transfer be-
tween the bq2040 and the external non-
volatile configuration memory.
Serial memory data and address
Bidirectional pin used to transfer address
and data to and from the bq2040 and the ex-
ternal nonvolitile configuration memory.
LED display segment outputs
Each output may drive an external LED.
Ground
Sense resistor input
The voltage drop (VSR) across pins SR and
VSS is monitored and integrated over time
to interpret charge and discharge activity.
The SR input is connected to the sense re-
sistor and the negative terminal of the
battery. VSR < VSS indicates discharge, and
VSR > VSS indicates charge. The effective
voltage drop, VSRO, as seen by the bq2040
is VSR + VOS. (See Table 3.)
SB
PSTAT
SMBD
SMBC
REF
VOUT
Display control input
DISP high disables the LED display. DISP
floating allows the LED display to be active
during charge if the rate is greater than
100mA. DISP low activates the display for
4 seconds.
Secondary battery input
Monitors the pack voltage through a high-
impedance resistor divider network. The
pack voltage is reported in the SBD register
function Voltage (0x09) and is monitored for
end-of-discharge voltage and charging volt-
age parameters.
Protector status input
Provides overvoltage status from the Li-Ion
protector circuit and can initiate a charge sus-
pend request.
SMBus data
Open-drain bidirectional pin used to transfer
address and data to and from the bq2040.
SMBus clock
Open-drain bidirectional pin used to clock
the data transfer to and from the bq2040.
Reference output for regulator
REF provides a reference output for an op-
tional FET-based micro-regulator.
Supply output
Supplies power to the external EEPROM con-
figuration memory.
2