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

±5%.

If the battery is within the configured temperature and

voltage limits, the IC begins fast charge.

The valid

pending state.

In this state pulse trickle charge is

applied to the battery and the LED flashes until the

voltage and temperature come into the allowed fast

Absent state. In this state the LED is off and trickle

charge is applied to the battery until the next new

charge cycle begins.

Fast charge continues until termination by one or more of

the five possible termination conditions:

∆V)

4

Corresponding

Fast-Charge

Rate

TM

Termination

Typical

Fast-

Charge

Time Limits

(minutes)

Typical PVD

and -

∆V

Hold-Off

Time (seconds)

Pulse-

Trickle

Rate

Pulse-

Trickle

Pulse Width

(ms)

Maximum

Synchronized

Sampling

Period

(seconds)

C/2

Mid

PVD

160

300

C/32

73

18.7

1C

Low

PVD

80

150

C/32

37

18.7

2C

High

-

∆V

40

75

C/32

18

9.4

Notes:

Tolerance on all timing is ±12%.

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

bq2002C

TD2002C1.eps

Fast Charging

VCC = 0

Fast Charging

CC Output

LED

Charge initiated by application of power

Charge initiated by battery replacement

Pulse-Trickle

See

Table 1

1s

Figure 4. Charge Cycle Phases