bq2013H
Gas Gauge IC for Power-
Assist Applications
Features
➤
Accurate measurement of available
charge in rechargeable batteries
➤
Designed for electric assist bicycles
and other applications
➤
Measures a wide dynamic current
range
➤
Supports NiCd, NiMH or lead acid
➤
Designed for battery pack inte-
gration
General Description
The bq2013H 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 resis-
tor connected in series between the
negative battery terminal and ground
to determine charge and discharge ac-
tivity of the battery. The bq2013H is
designed for high cpaacity battery
packs used in high-discharge rate sys-
tems.
Battery self-discharge is estimated
based on an internal timer and tem-
perature sensor. Compensations for
battery temperature, rate of charge,
and self-discharge are applied to the
charge counter to provide available
capacity information across a wide
range of operating conditions. Initial
battery capacity, self-discharge rate,
display mode, and charge compensa-
tion are set using the PROG
1-6
pins.
Actual battery capacity is automati-
cally “learned” in the course of a dis-
charge cycle from full to empty.
Nominal available charge may be
directly indicated using a five-seg-
ment LED display. These segments
are used to graphically indicate
nominal available charge.
The bq2013H supports a simple
single-line bi-directional serial link to
an external processor (common
ground). The bq2013H outputs bat-
tery information in response to exter-
nal commands over the serial link. To
support battery pack testing, the
outputs may also be controlled by
command. The external processor
may also overwrite some of the
bq2013H gas gauge data registers.
The bq2013H may operate directly
from four nickel cells or three lead
acid. With the REF output and an
external transistor, a simple, inexpen-
sive regulator can be built to provide
V
CC
from a greater number of cells.
Internal registers include available
charge, temperature, capacity, battery
ID, and battery status.
-
-
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
➤
A u to mat i c ch ar g e a nd s e l f -
discharge compensation using in-
ternal temperature sensor
➤
Simple single-wire serial commu-
nications port for subassembly
testing
➤
16-pin narrow SOIC
Pin Connections
LCOM
SEG1/PROG1
SEG2/PROG2
SEG3/PROG3
SEG4/PROG4
SEG5PROG5
PROG6
VSS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VCC
REF
DONE
HDQ
RBI
SB
DISP
SR
Pin Names
LCOM
SEG
1
/PROG
1
SEG
2
/PROG
2
SEG
3
/PROG
3
SEG
4
/PROG
4
SEG
5
/PROG
5
LED common output
LED segment 1/ Program
1 input
LED segment 2 / Program
2 input
LED segment 3/ Program
3 input
LED segment 4/ Program
4 input
LED segment 5/ Program
5 input
Program 6 input
REF
DONE
HDQ
RBI
SB
DISP
SR
V
CC
Voltage reference output
Fast charge complete
input
Serial communications
input/output
Register backup input
Battery sense input
Display control input
Sense resistor input
Supply voltage
16-Pin Narrow SOIC
PN2013.eps
PROG
6
SLUS120–MAY 1999 B
1
TI [ TEXAS INSTRUMENTS ]
