BQ2014H Datasheet, PDF (2/22 Pages) Texas Instruments – Low-Cost NiCd/NiMH Gas Gauge IC

bq2014H Preliminary
DISP
Pin Descriptions
LCOM LED common output
Open-drain output that switches V_CC 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)
Outputs that each may activate an LED to
sink the current sourced from LCOM.
PROG₁– Programmed full count selection inputs
PROG₂ (dual function with SEG1–SEG2)
Three-level input pins that 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)
Three-level input pins that define the scale
factor described in Table 2.
PROG₅ Self-discharge rate selection (dual func-
tion with SEG₅)
Three-level input pin that defines the
self-discharge and battery-compensation fac-
tors as shown in Table 1.
DONE Charge complete input
Communicates the status of an external
charge-controller such as the bq2004 Fast-
Charge IC to the bq2014H. Note: This pin
must be pulled down to V_SS using a 200kΩ
resistor.
V_SS
Ground
SR
Sense resistor input
The voltage drop (V_SR) across the sense re-
sistor R_S is monitored and integrated over
time to interpret charge and discharge activ-
ity. V_SR < V_SS indicates discharge, and V_SR >
V_SS indicates charge. The effective voltage
drop, V_SRO, as seen by the bq2014H is V_SR +
V_OS .
SB
RBI
HDQ
NC
REF
V_CC
Display control input
DISP high disables the LED display. DISP
tied to VCC allows PROGX 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
Monitors the battery cell-voltage potential
through a high-impedance resistive divider
network for end-of-discharge voltage (EDV)
thresholds and for battery-removed
detection.
Register backup input
Provides backup potential to the bq2014H reg-
isters while V_CC ≤ 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.
No connect
Voltage reference output
REF provides a voltage reference output for
an optional microregulator.
Supply voltage input
2