BQ2011K_11 Datasheet, PDF (1/22 Pages) Texas Instruments – Gas Gauge IC for High Discharge Rates

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
1
SEG1/PROG1
2
SEG2/PROG2
3
SEG3/PROG3
4
SEG4/PROG4
5
SEG5
6
SPFC
7
VSS
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
V_CC
V_SS
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