1
Features
➤ 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
c68 ∆Τ/∆ t minimum current
(Li-Ion), maximum tempera-
ture, and maximum charge
time
➤ Selectable top-off mode for
achieving maximum capacity
in NiMH batteries
➤ Programmable trickle-charge
mode for reviving deeply dis-
charged batteries and for
post-charge maintenance
➤ Built-in battery removal and
insertion detection
➤ Sleep mode for low power
consumption
General Description
The bq2000T is a programmable,
monolithic IC for fast-charge man-
agement of nickel cadmium
(NiCd), nickel metal-hydride
(NiMH), or lithium-ion (Li-Ion)
batteries in single- or
multi-chemistry applications. The
bq2000T detects the battery chem-
istry and proceeds with the opti-
mal charging and termination al-
gorithms. 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:
c110 Rate of temperature rise, c68 ∆Τ/∆ t
(for NiCd and NiMH)
c110 Minimum charging current (for
Li-Ion)
c110 Maximum temperature
c110 Maximum charge time
For safety, the bq2000T inhibits
fast charge until the battery volt-
age 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-frequency
comparator allows the bq2000T to
be the basis for a complete,
high-efficiency power-conversion
circuit for both nickel-based and
lithium-based chemistries.
bq2000T
SNS Current-sense
input
V
SS
System ground
LED Charge-status
output
BAT Battery-voltage
input
1
PN-2000.eps
8-Pin DIP or Narrow SOIC
or TSSOP
2
3
4
8
7
6
5
SNS
LED
BAT
V
SS
MOD
V
CC
TS
RC
Pin Connections Pin Names
Programmable Multi-Chemistry
Fast-Charge Management IC
SLUS149B–FEBRUARY 2001
TS Temperature-sense
input
RC Timer-program
input
V
CC
Supply-voltage
input
MOD Modulation-control
output