Datasheet

LTC4063
11
4063fc
operaTion
Figure 1. Adjustable Linear Regulator
applicaTions inForMaTion
Programming Charge Termination
The LTC4063 terminates a charge cycle using several
methods, allowing the designer considerable flexibility in
choosing
an
ideal charge termination algorithm. Table 1
shows a brief description of the different termination
methods and their behavior.
Charge Time Termination
Connecting a capacitor (C
TIMER
) to the TIMER pin enables
the timer and selects Charge Time Termination. The total
charge time is set by:
Time Hours
C
µF
Hours
TIMER
( )
.
•=
0 1
3
When the programmed time has elapsed, the charge
cycle terminates and the charger enters standby mode.
Subsequent recharge cycles terminate when half the
programmed time has elapsed.
The IDET pin determines the behavior of the CHRG output.
Connecting a resistor (R
DET
) from the IDET pin to ground
sets the charge current detection threshold, I
DETECT
:
I
R
R
I
V
R
or
R
V
I
DETECT
PROG
DET
CHG
DET
DET
DE
= =
=
10
100
100
•
TTECT
Table 1.
METHOD
Charge Time
Termination
Charge Current
Termination
TIMER
0.1µF to
GND
I
DET
R
DET
to
GND
CHARGER DESCRIPTION
Charges for 3 Hours. After 3 Hours, the Charger
Stops Charging and Enters Standby Mode.
Recharge Cycles Last for 1.5 Hours
Charges for 3 Hours. After 3 Hours, the Charger
Stops Charging and Enters Standby Mode.
Recharge Cycles Last for 1.5 Hours
Charges Until Charge Current Drops Below
I
DETECT
, Then Enters Standby Mode
Pull-Down State When Charging. High Impedance State
When Charging is Stopped
Pull-Down State When Charging. High Impedance State
When Charging is Stopped
CHRG OUTPUT DESCRIPTION
Pull-Down State While I
BAT
> I
DETECT
. High Impedance
State While I
BAT
< I
DETECT
or When Charging is Stopped
Pull-Down State While I
BAT
> I
DETECT
. High Impedance
State While I
BAT
< I
DETECT
or When Charging is Stopped
0.1µF to
GND
GND R
DET
to
GND
User-Selectable
Charge
Termination
V
CC
R
DET
to
GND
Charges Indefinitely Until CHGEN Pin is Pulled
High
V
CC
NC
Pull-Down State When Charging. High Impedance State
When Charging is Stopped
Pull-Down State When Charging. High Impedance State
When Charging is Stopped
GND NC
NC
Charges Indefinitely Until CHGEN Pin is Pulled
High. SmartStart is Disabled
Charges Indefinitely Until CHGEN Pin is Pulled
High. SmartStart is Disabled
Figure 1 shows how an external resistor divider sets the
regulator output voltage. The output voltage can be set
anywhere between 1.2V and 4.2V, although the upper
limit is limited by the battery voltage minus the regulator
dropout voltage.
V mV
R
R
OUT
= +






800 1
2
1
•
In order to maintain stability under light load conditions,
the maximum recommended value of R1 is 160k.
+
BAT
R2
C
OUT
SINGLE CELL
Li-Ion BATTERY
V
OUT
R1
4063 F01
OUT
FB
LTC4063
GND