Gauge IC. BQ2011K Datasheet

BQ2011K IC. Datasheet pdf. Equivalent


Part BQ2011K
Description Gas Gauge IC
Feature bq2011K Gas Gauge IC for High Discharge Rates Features ➤ Conservative and repeatable measurement .
Manufacture UNITRODE
Datasheet
Download BQ2011K Datasheet


bq2011K Gas Gauge IC for High Discharge Rates Features ➤ BQ2011K Datasheet
Recommendation Recommendation Datasheet BQ2011K Datasheet




BQ2011K
bq2011K
Gas Gauge IC for
High Discharge Rates
Features
Conservative and repeatable
measurement of available charge
in rechargeable batteries
Designed for portable equipment
such as power tools with high dis-
charge rates
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
Direct drive of LEDs for capacity
display
Self-discharge compensation us-
ing internal temperature sensor
Simple single-wire serial commu-
nications port for subassembly
testing
16-pin narrow SOIC
Pin Connections
General Description
The bq2011K Gas Gauge IC is in-
tended for battery-pack installation to
maintain an accurate record of a bat-
tery’s available charge. The IC moni-
tors a voltage drop across a sense re-
sistor connected in series between the
negative battery terminal and ground
to determine charge and discharge ac-
tivity of the battery. The bq2011K is
designed for systems such as power
tools with very high discharge rates.
Battery self-discharge is estimated
based on an internal timer and tem-
perature sensor. Compensations for
battery temperature and rate of
charge or discharge are applied to
the charge, discharge, and
selfdischarge calculations to provide
available charge information across
a wide range of operating conditions.
Initial battery capacity is set using
the PROG1-4 and SPFC pins. Actual
battery capacity is automatically
“learned” in the course of a dis-
charge cycle from full to empty and
may be displayed depending on the
display mode.
Pin Names
Nominal available charge may be di-
rectly indicated using a five-seg-
ment LED display. These segments
are used to graphically indicate
nominal available charge.
The bq2011K supports a simple
single-line bidirectional serial link to
an external processor (common
ground). The bq2011K outputs bat-
tery information in response to exter-
nal commands over the serial link. To
support subassembly testing, the
outputs may also be controlled by
command. The external processor
may also overwrite some of the
bq2011K gas gauge data registers.
The bq2011K may operate directly
from four cells. With the REF out-
put and an external transistor, a
simple, inexpensive regulator can be
built to provide VCC from a greater
number of cells.
Internal registers include available
charge, temperature, capacity, battery
ID, and battery status.
LCOM
SEG1/PROG1
SEG2/PROG2
SEG3/PROG3
SEG4/PROG4
SEG5
SPFC
VSS
1
2
3
4
5
6
7
8
16 VCC
15 REF
14 NC
13 DQ
12 RBI
11 SB
10 DISP
9 SR
16-Pin Narrow SOIC
PN2011JK.eps
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
LED segment 5
SPFC
Programmed full count
selection input
REF
NC
DQ
RBI
SB
DISP
SR
VCC
VSS
Voltage reference output
No connect
Serial communications
input/output
Register backup input
Battery sense input
Display control input
Sense resistor input
3.0–6.5V
Negative battery terminal
10/97 B
1



BQ2011K
bq2011K
Pin Descriptions
LCOM LED common
Open-drain output switches VCC to source cur-
rent for the LEDs. The switch is off during ini-
tialization to allow reading of PROG1-4 pull-up
or pull-down program resistors. LCOM is high
impedance when the display is off.
SEG1
SEG5
LED display segment outputs
Each output may activate an LED to sink
the current sourced from LCOM, the battery,
or VCC.
PROG1– Programmed full count selection inputs
PROG4 (dual function with SEG1 - SEG4)
These three-level input pins define the pro-
grammed full count (PFC) in conjunction
with SPFC pin, define the display mode and
enable or disable self-discharge.
SPFC Programmed full count selection input
This three-level input pin along with PROG1-3
define the programmed full count (PFC)
thresholds described in Table 1. The state of
the SPFC pin is only read immediately after
a reset condition.
SR 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 low side of
the sense resistor and battery pack ground
(see Figure 1). VSR > VSS indicates discharge,
and VSR < VSS indicates charge. The effec-
tive voltage drop, VSRO, as seen by the
bq2011K is VSR + VOS (see Table 4).
NC
DISP
SB
RBI
DQ
REF
VCC
VSS
No connect
Display control input
DISP floating allows the LED display to
be active during certain charge and dis-
charge conditions. Transitioning DISP
low activates the display for 4 ± 0.5 seconds.
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) threshold and maximum cell
voltage (MCV).
Register backup input
This input is used to provide backup poten-
tial to the bq2011K registers during periods
when VCC < 3V. A storage capacitor should
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







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