DPA424 Power Integrations, Inc., DPA424 Datasheet - Page 13

• Manufacturer Part Number: DPA424
• Description: Highly Integrated DC-DC Converter Ics For Distributed Power Architectures
• Manufacturer: Power Integrations, Inc.

Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)
Figure 15. Externally Set Current Limit.
Figure 17. Active-on (Fail Safe) Remote ON/OFF.
Figure 19. Active-on Remote ON/OFF with Externally Set Current
Voltage
Voltage
Voltage
Input
Input
Input
DC
DC
DC
+
+
+
-
Limit.
-
-
D
S
D
S
D
S
Q
CONTROL
CONTROL
CONTROL
R
X
X
X
R
IL
R
47 KΩ
Q
output or can be replaced by
a manual switch.
IL
R
Q
output or can be replaced
by a MOSFET or manual
switch.
Q
C
C
C
can be an optocoupler
R
R
can be an optocoupler
For R
See Figure 32 for other
resistor values (R
For R
ON/OFF
47 kΩ
I
I
LIMIT
LIMIT
For R
For R
IL
IL
= 12 kΩ
= 25 kΩ
I
I
LIMIT
LIMIT
= 64%
= 34%
PI-2625-040501
PI-2856-072602
PI-2836-050602
IL
IL
ON/OFF
= 12 kΩ
= 25 kΩ
= 64%
= 34%
IL
)
Figure 16. Current Limit Reduction with Line Voltage.
Figure 20. Active-off Remote ON/OFF with Externally Set Current
Figure 18. Active-off Remote ON/OFF. Maximum Duty Cycle will
Voltage
Voltage
Voltage
Input
Input
Input
DC
DC
DC
+
+
+
-
-
-
Limit.
be reduced.
R
LS
ON/OFF
ON/OFF
363 kΩ
47 kΩ
47 kΩ
D
D
S
S
D
S
Q
Q
CONTROL
CONTROL
CONTROL
R
R
X
X
R
4.2 kΩ
R
L
L
IL
IL
37.4 kΩ
37.4 kΩ
R
R
MC
MC
C
C
C
DPA423-426
I
I
LIMIT
LIMIT
Q
optocoupler output or
can be replaced
by a manual switch.
Q
optocoupler output
or can be replaced
by a manual switch.
=
=
R
R
can be an
100% @ 36 VDC
64% @ 72 VDC
can be an
For R
For R
I
I
PI-2857-050602
LIMIT
LIMIT
PI-2854-050602
PI-2855-050602
5/03
IL
IL
= 12 kΩ
= 25 kΩ
J
= 64%
= 34%
13