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.