Features

Fast charge and conditioning of

nickel cadmium or nickel-metal

hydride batteries

Hysteretic PWM switch-mode

current regulation or gated control

of an external regulator

Easily integrated into systems

or used as a stand-alone charger

Pre-charge qualification of temperature

and voltage

Direct LED outputs display

battery and charge status

Fast-charge termination by

Δ temperature/Δ time, -ΔV, maximum

voltage, maximum temperature,

and maximum time

Optional top-off charge

General Description

The bq2003 Fast Charge IC provides

comprehensive fast charge control

functions together with high-speed

switching power control circuitry on a

monolithic CMOS device.

Integration of closed-loop current

control circuitry allows the bq2003

to be the basis of a cost-effective solution

for stand-alone and systemintegrated

chargers for batteries of

one or more cells.

Switch-activated discharge-beforecharge

allows bq2003-based chargers

to support battery conditioning and

capacity determination.

High-efficiency power conversion is

accomplished using the bq2003 as a

hysteretic PWM controller for

switch-mode regulation of the charging

current. The bq2003 may alternatively

be used to gate an externally

regulated charging current.

Fast charge may begin on application

of the charging supply, replacement

of the battery, or switch depression.

For safety, fast charge is

inhibited unless/until the battery

temperature and voltage are within

configured limits.

Temperature, voltage, and time are

monitored throughout fast charge.

Fast charge is terminated by any of

the following:

Rate of temperature rise

(ΔT/Δt)

Negative delta voltage (-ΔV)

Maximum voltage

Maximum temperature

Maximum time

After fast charge, an optional top-off

phase is available. Constant-current

maintenence charge is provided

by an external trickle resistor.