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

➤ Configurable, direct LED outputs

display battery and charge status

➤ Fast-charge termination by Δ temperature/

Δ time, peak volume detection,

-ΔV, maximum voltage,

maximum temperature, and maximum

time

➤ Optional top-off charge and

pulsed current maintenance

charging

➤ Logic-level controlled low-power

mode (< 5μAstandby current)

General Description

The bq2004 Fast Charge IC provides

comprehensive fast charge control

functions together with high-speed

switching power control circuitry on a

monolithicCMOS device.

Integration of closed-loop current

control circuitry allows the bq2004

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 bq2004-based chargers

to support battery conditioning and

capacity determination.

High-efficiency power conversion is

accomplished using the bq2004 as a

hysteretic PWM controller for

switch-mode regulation of the charging

current. The bq2004 may alternatively

be used to gate an externally

regulated charging current.

Fast charge may begin on application

of the charging supply, replacement

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 time

(ΔT/Δt)

Peak voltage detection (PVD)

Negative delta voltage (-ΔV)

Maximum voltage

Maximum temperature

Maximum time

After fast charge, optional top-off

and pulsed current maintenance

phases are available.