BQ2050H_15 Datasheet, PDF (2/30 Pages) Texas Instruments – Low-Cost Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050H
Pin Descriptions
LCOM LED common output
This open-drain output switches VCC to
source current for the LEDs. The switch is
off during initialization to allow reading of
the soft pull-up or pull-down program resis-
tors. LCOM is also high impedance when the
display is off.
SEG1–
SEG5
LED display segment outputs (dual func-
tion with PROG₁–PROG₅)
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 scale 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
self-discharge and battery compensation fac-
tors as shown in Table 1.
CFC
Charge FET control output
This pin can be used as an additional control
to the charge FET of the Li-Ion pack protec-
tion circuitry.
VSS
Ground
SR
Sense resistor input
The voltage drop (VSR) across the sense re-
sistor R_S 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. V_SR < V_SS indicates discharge, and
V_SR > V_SS indicates charge. The effective
voltage drop, V_SRO, as seen by the bq2050H
is V_SR + V_OS .
DISP
SB
RBI
HDQ
PSTAT
REF
VCC
Display control input
DISP high disables the LED display. DISP
tied to V_CC allows PROG_X to connect di-
rectly to V_CC or V_SS 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-removed
detection.
Register backup input
This pin is used to provide backup potential to
the bq2050H registers during periods when
VCC ≤ 3V. A storage capacitor or a battery
can be connected to RBI.
Serial communication input/output
This is the open-drain bidirectional commu-
nications port.
Protector status input
This input provides overvoltage status from
the Li-Ion protector circuit. It should con-
nect to VSS when not used.
Voltage reference output for regulator
REF provides a voltage reference output for
an optional micro-regulator.
Supply voltage input
2