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 ΔT/Δt, 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 bq24401 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 bq24401 provides these charge termination

criteria:

? Rate of temperature rise (ΔT/Δt)

? Maximum temperature

? Maximum charge time

For safety, the bq24401 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 bq24401 uses

trickle-charge to condition the battery. For NiMH batteries, the bq24401 provides an optional top-off

charge to maximize the battery capacity.

The integrated high-speed comparator allows the bq24401 to be the basis for a complete,

high-efficiency battery charger circuit for nickel-based

chemistries.