13

LTC4063

4063fb

Charge Current Termination

Connecting the TIMER pin to ground selects Charge

Current Termination. With this method, the timer is

same equation stated in the previous section (repeated

here for convenience):

I

R

R

I

V

R

or

R

V

I

DETECT

PROG

DET

CHG

DET

DET

DETECT

==

=

10

100

100

•

The charge cycle terminates when the charge current falls

nal, filtered comparator to monitor the IDET pin. When the

cally 1.5ms), charging is terminated.

When charging, transient loads on the BAT pin can cause

the IDET pin to fall below 100mV for short periods of time

comparator ensures that transient loads of this nature do

not result in premature charge cycle termination. Once the

terminates the charge cycle.

The CHRG output is in its pull-down state when charging

and in its high impedance state once charging has stopped.

Figure 4 describes the operation of the LTC4063 charger

when charge current termination is used.

User-Selectable Charge Termination

Charge Termination, in which all internal termination

features are disabled. The charge cycle continues indefi-

nitely until the charger is shut down through the CHGEN

pin. The IDET pin programs the behavior of the CHRG

output in the same manner as when using Charge Time

state. When the charger enters constant-voltage mode

CHRG output becomes high impedance, indicating that

the battery is charged. If the IDET pin is not connected, the

CHRG output remains in its pull-down state until the

charger is shut down.

APPLICATIO S I FOR ATIO

CHARGE MODE

FULL CURRENT

IN VOLTAGE MODE

4063 F04

TRICKLE CHARGE MODE

1/10 FULL CURRENT

BAT > 2.9V

BAT < 2.9V

2.9V < BAT < 4.1V

BAT > 4.1V

BAT < 4.1V

CHGEN = 5V

OR

UVLO CONDITION

STANDBY MODE

NO CHARGE CURRENT

CHRG STATE: Hi-Z

SHUTDOWN MODE

CHRG STATE: Hi-Z

CHRG STATE: PULL-DOWN

CHRG STATE: PULL-DOWN

POWER ON

CHGEN = 0V

OR UVLO

CONDITION

STOPS

Figure 4. State Diagram of a Charge Cycle Using Charge Current Termination