Gauge IC. BQ2012 Datasheet

BQ2012 IC. Datasheet pdf. Equivalent

Part BQ2012
Description Gas Gauge IC
Feature Not Recommended For New Designs bq2012 Gas Gauge IC With Slow-Charge Control Features ➤ Conserva.
Manufacture UNITRODE
Datasheet
Download BQ2012 Datasheet

Not Recommended For New Designs bq2012 Gas Gauge IC With S BQ2012 Datasheet
Recommendation Recommendation Datasheet BQ2012 Datasheet




BQ2012
Not Recommended For New Designs
bq2012
Gas Gauge IC With
Slow-Charge Control
Features
Conservative and repeatable
measurement of available charge
in rechargeable batteries
Charge control output
Designed for battery pack inte-
gration
- 120µA typical standby current
(self-discharge estimation mode)
- Small size enables imple-
mentations
in
as
little
as
1
2
square inch of PCB
Integrate within a system or as a
stand-alone device
- Display capacity via single-
wire serial communication
port or direct drive of LEDs
Measurements compensated for
current and temperature
Self-discharge compensation us-
ing internal temperature sensor
16-pin narrow SOIC
General Description
The bq2012 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 a 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,
discharge, and self-discharge calcu-
lations to provide available charge
information across a wide range of
operating conditions. Battery capac-
ity is automatically recalibrated, or
“learned,” in the course of a dis-
charge cycle from full to empty.
The bq2012 includes a charge con-
trol output that, when used with
other full-charge safety termination
methods, can provide a cost-effective
means of controlling charge based
on the battery's charge state.
Nominal available charge may be di-
rectly indicated using a five- or six-
segment LED display. These seg-
ments are used to graphically indi-
cate nominal available charge.
The bq2012 supports a simple
single-line bidirectional serial link to
an external processor (common
ground). The bq2012 outputs battery
information in response to external
commands over the serial link.
Internal registers include available
charge, temperature, capacity, battery
ID, battery status, and programming
pin settings. To support subassembly
testing, the outputs may also be con-
trolled. The external processor may
also overwrite some of the bq2012 gas
gauge data registers.
The bq2012 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
SEG6/PROG6
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
PN201201.eps
9/96 B
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
SEG6/PROG6 LED segment 6/
program 6 input
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
1



BQ2012
Not Recommended For New Designs
bq2012
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
SEG6
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.
PROG3Gas 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 selfdis-
charge compensation rate shown in Table 1.
PROG6 Display mode selection (dual function
with SEG6)
This three-level pin defines the display op-
eration shown in Table 1.
CHG
Charge control output
This open-drain output becomes active low
when charging is allowed. Valid charging
conditions are described in the Charge Con-
trol section.
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
bq2012 is VSR + VOS (see Table 5).
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 a valid
charge or during discharge if the NAC regis-
ter is updated at a rate equivalent 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 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 end-of-
discharge voltage (VEDVF) and is low following
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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