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
peak voltage (PVD), minimum
current (Li-Ion), maximum
temperature, 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 bq2000 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
bq2000 detects the battery chemistry
and proceeds with the optimal charg-
ing and termination algorithms. This
process eliminates undesirable under-
charged or overcharged conditions
and allows accurate and safe termi-
nation of fast charge.
Depending on the chemistry, the
bq2000 provides a number of charge
termination criteria:
c110 Peak voltage, PVD (for NiCd and
NiMH)
c110 Minimum charging current (f or
Li-Ion)
c110 Maximum temperature
c110 Maximum charge time
For safety, the bq2000 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
bq2000 uses trickle-charge to
condition the battery. For NiMH
batteries, the bq2000 provides an
optional top-off charge to maximize
the battery capacity.
The integrated high-frequency com-
parator allows the bq2000 to be the
basis for a complete, high-efficiency
power-conversion circuit for both
nickel-based and lithium-based
chemistries.
bq2000
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
SLUS138B–FEBRUARY 2001 F
TS Temperature-sense
input
RC Timer-program input
V
CC Supply-voltage input
MOD Modulation-control
output