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-

Starting A Charge Cycle

Either of two events starts a charge cycle (see Figure 4):

2. Voltage at the BAT pin falling through the maximum

If the battery is within the configured temperature and

voltage limits, the IC begins fast charge. The valid bat-

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:

Tolerance on all timing is

±12%.

Table 1. Fast-Charge Safety Time/Hold-Off/Top-Off Table

TD2002EG.eps

Fast Charging

VCC = 0

Fast Charging

CC Output

LED

Charge initiated by application of power

Charge initiated by battery replacement

Pulse-Trickle

Top-Off

(optional)

73ms

1.17s

1.17s

See Table 1

Figure 4. Charge Cycle Phases