Gauge IC. BQ2014 Datasheet

BQ2014 IC. Datasheet pdf. Equivalent

Part BQ2014
Description Gas Gauge IC
Feature Not Recommended For New Designs bq2014 Gas Gauge IC with External Charge Control Features ➤ Conse.
Manufacture UNITRODE
Datasheet
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BQ2014
Not Recommended For New Designs
bq2014
Gas Gauge IC with External Charge Control
Features
Conservative and repeatable
measurement of available charge
in rechargeable batteries
Charge control output operates an
external charge controller such as
the bq2004 Fast Charge IC
Designed for battery pack inte-
gration
- 120µA typical standby current
Display capacity via single-wire
serial communication port or di-
rect drive of LEDs
Measurements compensated for
current and temperature
Self-discharge compensation using
internal temperature sensor
User-selectable end-of-discharge
threshold
Battery voltage, nominal avail-
able charge, temperature, etc.
available over serial port
16-pin narrow SOIC
General Description
The bq2014 Gas Gauge IC is in-
tended for battery-pack or in-system
installation to maintain an accurate
record of available battery charge.
The IC monitors the voltage drop
across a sense resistor connected in
series between the negative battery
terminal and ground to determine
charge and discharge activity of the
battery.
Self-discharge of NiMH and NiCd
batteries is estimated based on an
internal timer and temperature sen-
sor. Compensations for battery tem-
perature and rate of charge or dis-
charge are applied to the charge, dis-
charge, and self-discharge calcula-
tions to provide available charge in-
formation across a wide range of op-
erating conditions. Battery capacity
is automatically recalibrated, or
“learned,” in the course of a dis-
charge cycle from full to empty.
The bq2014 includes a charge con-
trol output that controls an external
Fast Charge IC such as the bq2004.
Nominal Available Charge (NAC)
may be directly indicated using a
five-segment LED display.
The bq2014 supports a simple single-
line bidirectional serial link to an ex-
ternal processor (with a common
ground). The bq2014 outputs battery
information in response to external
commands over the serial link.
Internal registers include available
charge, temperature, capacity, bat-
tery voltage, battery ID, battery
status, and programming pin set-
tings. To support subassembly test-
ing, the outputs may also be con-
trolled. The external processor may
also overwrite some of the bq2014
gas gauge data registers.
The bq2014 may operate directly
from three or four cells. With the
REF output and an external transis-
tor, a simple, inexpensive regulator
can be built to provide VCC across a
greater number of cells.
Pin Connections
LCOM
SEG1/PROG1
SEG2/PROG2
SEG3/PROG3
SEG4/PROG4
SEG5/PROG5
DONE
VSS
1
2
3
4
5
6
7
8
16 VCC
15 REF
14 CHG
13 DQ
12 EMPTY
11 SB
10 DISP
9 SR
16-Pin Narrow SOIC
PN201401.eps
12/95 C
Pin Names
LCOM
LED common output
SEG1/PROG1 LED segment 1/
program 1 input
SEG2/PROG2 LED segment 2/
program 2 input
SEG3/PROG3 LED segment 3/
program 3 input
SEG4/PROG4 LED segment 4/
program 4 input
SEG5/PROG5 LED segment 5/
program 5 input
DONE
Fast charge complete
1
REF
CHG
DQ
EMPTY
SB
DISP
SR
VCC
VSS
Voltage reference output
Charge control output
Serial communications
input/output
Empty battery indicator
output
Battery sense input
Display control input
Sense resistor input
3.0–6.5V
System ground



BQ2014
Not Recommended For New Designs
bq2014
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 programming resistors.
LCOM is also in a high impedance state
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 imputs
PROG5 (dual function with SEG1—SEG5)
These three-level input pins define the pro-
grammed full count (PFC) thresholds de-
scribed in Table 2.
PROG3– Gas gauge rate selection inputs (dual
PROG4 function with SEG3—SEG4)
These three-level input pins define the pro-
grammed full count (PFC) thresholds de-
scribed in Table 2.
PROG5 Self-discharge rate selection (dual func-
tion with SEG5)
This three-level input pin defines the self-
discharge compensation rate shown in Ta-
ble 1.
CHG
Charge control output
This open-drain output becomes active high
when charging is allowed.
DONE Fast charge complete
This input is used to communicate the
status of an external charge controller such
as the bq2004 Fast Charge IC. Note: This
pin must be pulled down to VSS using a
200Kresistor.
SR
DISP
SB
EMPTY
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 to the high side of
the sense resistor. VSR < VSS indicates dis-
charge, and VSR > VSS indicates charge. The
effective voltage drop VSRO, as seen by the
bq2014, is VSR + VOS (see Table 5).
Display control input
DISP high disables the LED display. DISP
tied to VCC allows PROGX to connect di-
rectly to VCC or VSS instead of through a
pull-up or pull-down reistor. DISP floating
allows the LED display to be active during
a valid charge or during discharge if the
NAC register is updated at a rate equiva-
lent to VSRO -4mV. DISP low activates
the display. See Table 1.
Secondary battery input
This input monitors the single-cell voltage
potential through a high-impedance resis-
tive divider network for the end-of-discharge
voltage (EDV) thresholds,maximum charge
voltage (MCV), and battery removed.
Battery empty output
This open-drain output becomes high-
impedance on detection of a valid final end-
of-discharge voltage (VEDVF) and is low fol-
lowing the next application of a valid charge.
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





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