1FEATURES

• 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 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.