1
Features
Safe management of fast
charge for NiCd, NiMH, or Li-
Ion battery packs
High-frequency switching con-
troller for efficient and simple
charger design
Pre-charge qualification for
detecting shorted, damaged, or
overheated cells
Fast-charge termination by
T/
t
minimum
(Li-Ion), maximum tempera-
ture, and maximum charge
time
current
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 manage-
ment of nickel cadmium (NiCd),
nickel metal-hydride (NiMH), or lith-
ium-ion (Li-Ion) batteries in single- or
multi-chemistry applications. The
bq2000T detects the battery chemis-
try and proceeds with the optimal
charging and termination algorithms.
This process eliminates undesirable
undercharged or overcharged condi-
tions and allows accurate and safe
termination of fast charge.
Depending on the chemistry, the
bq2000T provides a number of
charge termination criteria:
Rate of temperature rise,
T/
t (for
NiCdandNiMH)
Minimum charging current (for
Li-Ion)
Maximum temperature
Maximum charge time
For safety, the bq2000T inhibits fast
charge until the battery voltage 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.
batteries, the bq2000T provides an
optional top-off charge to maximize
the battery capacity.
For NiMH
The integrated high-frequency com-
parator 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
VSS
MOD
VCC
TS
RC
Pin Connections
Pin Names
Programmable Multi-Chemistry
Fast-Charge Management IC
SLUS149A–FEBRUARY 2000
TS
Temperature-sense
input
RC
Timer-program input
V
CC
Supply-voltage input
MOD
Modulation-control
output