BQ24450 Datasheet, PDF (1/20 Pages) Texas Instruments – INTEGRATED CHARGE CONTROLLER FOR LEAD-ACID BATTERIES

bq24450
www.ti.com ..................................................................................................................................................................................................... SLUS929 – APRIL 2009
INTEGRATED CHARGE CONTROLLER FOR LEAD-ACID BATTERIES
FEATURES
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• Regulates Both Voltage and Current During
Charging
• Precision Temperature-Compensated
Reference:
– Maximizes Battery Capacity Over
Temperature
– Ensures Safety While Charging Over
Temperature
• Optimum Control to Maximize Battery Capacity
and Life
• Supports Different Configurations
• Minimum External Components
• Available in 16-Pin PDIP and SOIC (DW)
APPLICATIONS
• Emergency Lighting Systems
• Security and Alarm Systems
• Telecommunication Backup Power
• Uninterruptible Power Supplies
DESCRIPTION
The bq24450 contains all the necessary circuitry to optimally control the charging of valve-regulated lead-acid
batteries. The IC controls the charging current as well as the charging voltage to safely and efficiently charge the
battery, maximizing battery capacity and life. Depending on the application, the IC can be configured as a simple
constant-voltage float charge controller or a dual-voltage float-cum-boost charge controller.
The built-in precision voltage reference is especially temperature-compensated to track the characteristics of
lead-acid cells, and maintains optimum charging voltage over an extended temperature range without using any
external components. The ICs low current consumption allows for accurate temperature monitoring by minimizing
self-heating effects.
The IC can support a wide range of battery capacities and charging currents, limited only by the selection of the
external pass transistor. The versatile driver for the external pass transistor supports both NPN and PNP types
and provides at least 25mA of base drive.
In addition to the voltage- and current-regulating amplifiers, the IC features comparators that monitor the
charging voltage and current. These comparators feed into an internal state machine that sequences the charge
cycle. Some of these comparator outputs are made available as status signals at external pins of the IC. These
status and control pins can be connected to a processor, or they can be connected up in flexible ways for
standalone applications.
External
Supply
TYPICAL APPLICATION SCHEMATIC
R_ISNS
Q_EXT
VRLA
Battery
3
2
4
ISNSP ISNSM IFB
5 IN
1 _ISNS
bq24450
16 15
DRVC DRVE
PRE-CHG ¹¹
CE 12
VFB 13
8 BSTOP
STAT1 10
9 STAT2
GND
6
COMP
14
PGOOD ⁷
C_COMP
R_T R_A
R_B
R_D
R_C
A dual-level Float-cum-Boost Charger with Pre-Charge
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009, Texas Instruments Incorporated