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.