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Measures only 2.5 (L) x 0.7 (W) inches
Incl ud e s G as Ga u g e I C, c o nf i g u r a t io n
EEPROM, and sense resistor
Five onboard state-of-charge LEDs with
push-button activation
Low operating current for minimal battery
drain
A module development kit is also available for the
bq2145. The bq2145B-KT or the bq2145LB-KT includes
one configured module and the following:
1)
An EV2200-45 interface board that allows connec-
tion to the serial port of any AT-compatible com-
puter.
Menu-driven software to display charge/discharge
activity and to allow user interface to the Gas
Gauge IC and serial E
2
PROM from any standard
Windows 95 or 3.1x PC.
Critical battery information available over two-wire
serial port
General Description
The bq2145 Smart Battery Module provides a complete
solution for the design of intelligent battery packs. The
bq2145 uses the SMBus protocol and supports Smart
Battery Data commands in the SMB/SBD specifications.
Designed for battery pack integration, the bq2145 com-
bines the bq2945 Gas Gauge IC with a serial EEPROM
on a small printed circuit board. The board includes all
the necessary components to accurately monitor battery
capacity and communicate critical battery parameters to
the host system or battery charger. The bq2145 also in-
cludes five LEDs. The push-button switch activates the
LEDs to show remaining battery capacity in 20% incre-
ments.
Contacts are provided on the bq2145 for direct connec-
tion to the battery stack (B+, B-) and the two-wire inter-
face (C, D). Please refer to the bq2945 data sheet for
specific information on the operation of the Gas Gauge
and communication interface.
Unitrode configures the bq2145 based on the informa-
tion requested in Table 1. The configuration defines the
pack voltage, capacity, and chemistry and charge control
parameters. The Smart Battery Module uses the on-
board sense resistor to track charge and discharge activ-
ity of the battery pack. Figure 1 shows how the module
connects to the cells.
2)
Pin Descriptions
B+
P-
C
D
B-
CP2
CP1
BAT+/Battery positive/Pack positive
PACK-/Pack negative
SMBC/Communications clock
SMBD/Serial data
BAT-/Battery negative
Control pin 2
Control pin 1
5/99
1
1
2
3
4
5
6
7
