Datasheet

A ground-referenced negative temperature coefficient ther-
mistor placed near the battery may be used as a low-cost
temperature-to-voltage transducer. The temperature
sense voltage input at TS is developed using a resistor-
thermistor network between V
CC
and V
SS
. See Figure 1.
Starting A Charge Cycle
Either oftwoevents starts a charge cycle (see Figure 4):
1. Application of power to V
CC
or
2. Voltage at the BAT pin falling through the maximum
cell voltage V
MCV
where
V
MCV
= 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 V
LBAT
<V
BAT
<V
MCV
,where
4
bq2002E/G
Corre
-
sponding
Fast-Charge
Rate TM Termination
Typical Fast-
Charge and
Top-Off
Time Limits
(minutes)
Typical PVD
and -
∆
V
Hold-Off Time
(seconds)
Top-Off
Rate
Pulse-
Trickle
Rate
Pulse-
Trickle
Width
(ms)
Maximum
Synchro
-
nized
Sampling
Period
(seconds)
bq2002E bq2002G
C/2 Mid PVD 200 160 300 Disabled C/32 73 18.7
1C Low PVD 80 80 150 C/16 C/32 37 18.7
2C High -
∆
V 40 40 75 Disabled C/32 18 9.4
Notes: Typical conditions = 25°C, V
CC
= 5.0V
Mid = 0.5
*
V
CC
±
0.5V
Tolerance on all timing is
±
12%.
Table 1. Fast-Charge Safety Time/Hold-Off/Top-Off Table
TD2002EG.eps
Fast ChargingV
CC
= 0 Fast Charging
CC Output
LED
Charge initiated by application of power
Charge initiated by battery replacement
Pulse-TrickleTop-Off
(optional)
73ms
1.17s 1.17s
See Table 1
Figure 4. Charge Cycle Phases