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.