Features
Complete bq2004/bq2014 battery management
solution for NiCd or NiMH pack
Accurate battery state-of-charge monitoring
Reliable fast charge termination
Automatic full capacity calibration
Battery information available over a single-wire
bi-directional serial port
Nominal capacity, cell chemistry, and charge control
parameters pre-configured
Compact size for battery pack integration
General Description
The bq2164 Gas Gauge Module provides a complete and
compact battery management solution for NiCd and NiMH
battery packs. Designed for battery pack integration, the
bq2164 combines the bq2014 Gas Gauge IC with the
bq2004 Fast-Charge IC on a small printed circuit board.
The board includes all the necessary components to accu-
rately monitor the capacity and reliably terminate fast
charge of 5 to 10 series cells.
The gas gauge IC uses the onboard sense resistor to track
charge and discharge activity of the battery pack. The fast
charge IC gates a current-limited or constant-current charg-
ing supply connected to PACK+. Charging termination is
based on
T/t or -V/PVD, maximum temperature, time,
and voltage. The bq2004 signals charge completion to the
bq2014 to indicate full capacity. The charge complete signal
to the gas gauge eliminates the need to fully cycle the bat-
tery pack to initially calibrate full pack capacity.
Contacts are provided on the bq2164 for direct connec-
tion to the battery stack (BAT+, BAT-), the gas gauge's
c o m m u n i c a t i o n s p o r t ( D Q ) , a n d t h e t h e r m i s t o r
(THERM+, THERM). The thermistor is required for
temperature fast charge termination. Please refer to the
bq2004 and bq2014 data sheets for the specifics on the
operation of the gas gauge and the fast charge ICs.
Unitrode configures the bq2164 based on the informa-
tion requested in Table 1. The configuration defines
the number of series cells, the nominal battery pack
capacity, the self-discharge rate, and the fast charge
control parameters. The control parameters depend on
the charge rate, cell chemistry and termination technique
specified in the configuration table. They consist of the fast
charge hold-off, safety timers, and the pulse trickle rate as
shown in the bq2004 data sheet. The bq2164 is optimized for
temperature termination with the thermistor provided with
the development kit. Figure 1 shows how the module con-
nects to the cells.
The sense resistor value and type should also be specified
on the configuration sheet. The two options available are
a 3W through-hole type or a 1W surface-mount type.
Please refer to the application note entitled "A Tutorial for
Gas Gauging" to select the proper value.
A module development kit is also available for the
bq2164. The bq2164B-KT includes one configured mod-
ule and the following:
1)
A serial interface board that allows connection to
the RS-232 port of an AT-compatible computer.
2)
Menu-driven software with the bq2164 to display
charge/discharge activity and to allow user inter-
face to the bq2014 from any standard DOS PC.
3)
Source code for the TSR.
4)
A Philips 10K NTC Thermistor type 2322-640-
63103.
Pin Description
P1
DQ/Serial communication port
P2
BAT+/Battery positive
P3
PACK+/Pack positive
P4
PACK-/Pack negative
P5
BAT-/Battery negative
P6
THERM+/Thermistor positive
P7
THERM-/Thermistor negative
P8
MOD/Fast charge control output
1
NiCd or NiMH Gas Gauge Module
with Fast-Charge Control
bq2164
9/96
5-2
bq2164
FG216401.eps
Battery Pack
P5
P4
bq2164
Load
Charger
Cells
PACK+
PACK-
P2
P3
Figure 1. Module Connection Diagram
Customer Name: ___________________________________________________________________________
Contact: _________________________________________
Phone: ______________________________
Address: _________________________________________________________________________________
_________________________________________________________________________________
Sales Contact: ____________________________________
Phone: ______________________________
Number of series battery cells (5-10)
________________________________________
Battery type (NiCd or NiMH)
________________________________________
Battery pack capacity (mAh)
________________________________________
Discharge rate into load (2.0A max.)
Min.
Avg.
Max.
Sense resistor type:
(Thru-hole (3W) or surface-mount (1W))
________________________________________
Sense resistor size in m
(0.1 standard)
________________________________________
Fast charge current (2.0A max.)
________________________________________
Charge voltage (V)
________________________________________
Temperature termination (enabled/disabled)
________________________________________
PVD or -
V termination
________________________________________
FAE Approval _____________________________________
Date ________________________________
Table 1. bq2164 Module Configuration
5-5
bq2164
Absolute Maximum Ratings
Symbol
Parameter
Minimum
Maximum
Unit
Notes
P
SR
Continuous sense resis-
tor power dissipation
-
3
W
Thru-hole sense resistor
-
1
W
Surface-mount sense resistor
V
CHG
Charging voltage
-
20
V
T
OPR
Operating temperature
0
+70
C
Commercial
T
STR
Storage temperature
-40
+85
C
Note:
Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional opera-
tion should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Expo-
sure to conditions beyond the operational limits for extended periods of time may affect device reliability.
DC Electrical Characteristics
(TA = TOPR)
Symbol
Parameter
Minimum
Typical
Maximum
Unit
Conditions/Notes
NumCell
Number of cells in battery
pack
5
-
10
-
BAT+
Positive terminal of pack
GND
NumCell
1.2V
*
NumCell
1.8V
*
V
BAT-
Negative terminal of pack
GND - 0.3
-
GND+2.0
V
I
CC
Supply current at BAT+ ter-
minal (no external loads)
-
200
300
A
I
CHG
Charge current
-
-
2
A
I
DSCHG
Discharge current
-
-
2
A
R
DQ
Internal pull-down
500k
-
-
1
I
OL
Open-drain sink current DQ
-
-
5.0
mA
1
V
OL
Open-drain output low, DQ
-
-
0.5
V
1
I
OL
< 5mA
V
IHDQ
DQ input high
2.5
-
-
V
1
V
IHDQ
DQ input low
-
-
0.8
V
1
V
OS
Voltage offset
150
V
1
Note:
1. Characterized on PCB, IC 100% tested.
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