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
D ∆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:
n
Rate of temperature rise, D ∆Τ/∆t
(for NiCd and NiMH)
n
Minimum charging current (for
Li-Ion)
n
Maximum temperature
n
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
VSS
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
VSS
MOD
VCC
TS
RC
Pin Connections
Pin Names
Programmable Multi-Chemistry
Fast-Charge Management IC
SLUS149B–FEBRUARY 2001
TS
Temperature-sense
input
RC
Timer-program
input
VCC
Supply-voltage
input
MOD
Modulation-control
output
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