BQ2002FSNTRG4 Datasheet, PDF (4/17 Pages) Texas Instruments – NiCd/NiMH Fast-Charge Management ICs

bq2002/F
VCC = 0
Fast Charging
Top-Off
(optional)
Pulse-Trickle
Fast Charging
CC Output
286 s
286 s
LED
4576 s
Charge initiated by application of power
See
Table 1
Charge initiated by battery replacement
TD2002F1.eps
Figure 4. Charge Cycle Phases
Starting A Charge Cycle
Either of two events starts a charge cycle (see Figure 4):
1. Application of power to VCC or
2. Voltage at the BAT pin falling through the maximum
cell voltage VMCV where
VMCV = 2V ±5%.
If the battery is within the configured temperature and
voltage limits, the IC begins fast charge. The valid bat-
tery voltage range is VBAT < VMCV. The valid tempera-
ture range is VTS > VTCO where
VTCO = 0.5 ∗ VCC ±5%.
If the battery voltage or temperature is outside of these
limits, the IC pulse-trickle charges until the next new
charge cycle begins.
Fast charge continues until termination by one or more of
the five possible termination conditions:
n Peak voltage detection (PVD)
n Negative delta voltage (-∆V)
n Maximum voltage
n Maximum temperature
n Maximum time
Table 1. Fast-Charge Safety Time/Hold-Off Table
Corresponding
Fast-Charge
Rate
TM
Termination
Typical Fast-Charge
and Top-Off
Time Limits
(minutes)
bq2002 bq2002F
Typical PVD
Pulse-
and -∆V Hold-Off Top-Off Trickle
Time (seconds) Rate Rate
Pulse-
Trickle
Period
(ms)
C/2
Mid
PVD
160
160
600
C/32 C/64
9.15
1C
Low
PVD
80
100
300
C/16 C/64
18.3
2C
High
-∆V
40
40
150
Disabled C/32
18.3
Notes:
Typical conditions = 25°C, VCC = 5.0V.
Mid = 0.5 _* VCC ± 5V
Tolerance on all timing is ± 20%.
4