1FEATURES

• Safe Management of Fast Charge for NiCd and

NiMH Battery Packs

• High-Frequency Switching Controller for

Efficient and Simple Charger Design

• Pre-Charge Qualification for Detecting

Shorted, Damaged, or Overheated Cells

• Fast-Charge Termination by Peak Voltage

(PVD), Maximum Temperature, and Maximum

Charge Time

• Selectable Top-Off Mode for Achieving

Maximum Capacity in NiMH Batteries

• Programmable Trickle-Charge Mode for

Reviving Deeply Discharged Batteries and for

Postcharge Maintenance

• Built-in Battery Removal and Insertion

Detection

• Sleep Mode for Low Power Consumption

APPLICATIONS

• Nickel Charger

• High-Power, Multi-Cell Charger

GENERAL DESCRIPTION

The bq24400 is a programmable, monolithic IC for

fast-charge management of nickel cadmium (NiCd)

and nickel metal-hydride (NiMH) in single or multi-cell

applications.

The bq24400 provides these charge termination

criteria:

• Peak voltage, PVD

• Maximum temperature

• Maximum charge time

For safety, the bq24400 inhibits fast charge until the

battery voltage and temperature are within

user-defined limits. If the battery voltage is below the

low-voltage threshold, the bq24400 uses

trickle-charge to condition the battery. For NiMH batteries, the bq24400 provides an optional top-off

charge to maximize the battery capacity.

The integrated high-speed comparator allows the

bq24400 to be the basis for a complete, high-efficiency battery charger circuit for nickel-based

chemistries.