BQ2050_15 Datasheet, PDF (1/27 Pages) Texas Instruments – Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050
Lithium Ion Power Gauge™ IC
Features
➤ Conservative and repeatable
measurement of available capac-
ity in Lithium Ion rechargeable
batteries
➤ Designed for battery pack inte-
gration
- 120µA typical operating
current
- 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 bq2050 Lithium Ion Power
Gauge™ IC is intended for battery-
pack or in-system installation to
maintain an accurate record of
available battery capacity. The IC
monitors a voltage drop across a
sense resistor connected in series
between the negative battery termi-
nal and ground to determine
charge and discharge activity of
the battery. Compensations for bat-
tery temperature and rate of charge
or discharge are applied to the
charge, discharge, and self-discharge
calculations to provide available ca-
pacity information across a wide
range of operating conditions. Bat-
tery capacity is automatically recali-
brated, or “learned,” in the course of
a discharge cycle from full to empty.
Nominal available capacity may be
directly indicated using a five-
segment LED display. These seg-
ments are used to graphically indi-
cate available capacity. The bq2050
supports a simple single-line bidi-
rectional serial link to an external
processor (common ground). The
bq2050 outputs battery information
in response to external commands
over the serial link.
The bq2050 may operate directly
from one cell (VBAT > 3V). With the
REF output and an external transis-
tor, a simple, inexpensive regulator
can be built for systems with more
than one series cell.
Internal registers include available
capacity, temperature, scaled avail-
able energy, 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 bq2050
power gauge data registers.
Pin Connections
Pin Names
LCOM
1
SEG1/PROG1
2
SEG2/PROG2
3
SEG3/PROG3
4
SEG4/PROG4
5
SEG5/PROG5
6
PROG6
7
VSS
8
16
VCC
15
REF
14
N/C
13
DQ
12
RBI
11
SB
10
DISP
9
SR
16-Pin Narrow SOIC
PN205001.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/PROG5 LED segment 5/
program 5 input
PROG6
Program 6 input
REF
N/C
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
System ground
9/96 C
1