1FEATURES
• Safe Management of Fast Charge for NiCd,
NiMH, or Li-Ion 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 for Nickel
Chemistries, Minimum Current for Li-Ion
Chemistries, 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
• Multi-Chemistry Charger
• Nickel Charger
• High-Power, Multi-Cell Charger

GENERAL DESCRIPTION
The bq2000T is a programmable, monolithic IC for
fast-charge management of nickel cadmium (NiCd),
nickel metal-hydride (NiMH), or lithium-ion (Li-Ion)
batteries in single- or multi-chemistry applications. The bq2000T chooses the proper battery chemistry
(either nickel or lithium) and proceeds with the
optimal charging and termination algorithms. This
process eliminates undesirable, undercharged, or
overcharged conditions, and allows accurate and safe
termination of fast charge.
Depending on the chemistry, the bq2000T provides a
number of charge termination criteria:
• Rate of temperature rise (ΔT/Δt) (for NiCd and
NiMH)
• Minimum charge current (for Li-Ion)
• Maximum temperature
• Maximum charge time
For safety, the bq2000T 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 bq2000T uses
trickle-charge to condition the battery. For NiMH
batteries, the bq2000T provides an optional top-off
charge to maximize the battery capacity.
The integrated high-speed comparator allows the
bq2000T to be the basis for a complete,
high-efficiency battery charger circuit for both
nickel-based and lithium-based chemistries.