BQ2050_15 Datasheet, PDF (2/27 Pages) Texas Instruments – Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050
Pin Descriptions
LCOM LED common output
Open-drain output switches VCC to source
current for the LEDs. The switch is off dur-
ing initialization to allow reading of the soft
pull-up or pull-down program resistors.
LCOM is also high impedance when the dis-
play is off.
SEG1–
SEG5
LED display segment outputs (dual func-
tion with PROG1–PROG6)
Each output may activate an LED to sink
the current sourced from LCOM.
PROG1– Programmed full count selection inputs
PROG2 (dual function with SEG1–SEG2)
These three-level input pins define the pro-
grammed full count (PFC) thresholds de-
scribed in Table 2.
PROG3– Power gauge rate selection inputs (dual
PROG4 function with SEG3–SEG4)
These three-level input pins define the scale
factor described in Table 2.
PROG5 Self-discharge rate selection (dual func-
tion with SEG5)
This three-level input pin defines the
selfdischarge and battery compensation fac-
tors as shown in Table 1.
PROG6 Capacity initialization selection
This three-level pin defines the battery state
of charge at reset as shown in Table 1.
N/C
No connect
SR
DISP
SB
RBI
DQ
REF
VCC
VSS
Sense resistor input
The voltage drop (VSR) across the sense re-
sistor RS is monitored and integrated over
time to interpret charge and discharge activ-
ity. The SR input is tied between the nega-
tive terminal of the battery and the sense re-
sistor. VSR < VSS indicates discharge, and VSR
> VSS indicates charge. The effective voltage
drop, VSRO, as seen by the bq2050 is VSR +
VOS .
Display control input
DISP high disables the LED display. DISP
tied to VCC allows PROGX to connect directly
to VCC or VSS instead of through a pull-up or
pull-down resistor. DISP floating allows the
LED display to be active during charge.
DISP low activates the display. See Table 1.
Secondary battery input
This input monitors the battery cell voltage
potential through a high-impedance resis-
tive divider network for end-of-discharge
voltage (EDV) thresholds, and battery re-
moved.
Register backup input
This pin is used to provide backup potential to
the bq2050 registers during periods when
VCC ≤ 3V. A storage capacitor or a battery
can be connected to RBI.
Serial I/O pin
This is an open-drain bidirectional pin.
Voltage reference output for regulator
REF provides a voltage reference output for
an optional micro-regulator.
Supply voltage input
Ground
2