TOP242-250
Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins
+
+
VUV = IUV x RLS
VOV = IOV x RLS
For RLS = 2 MΩ
VUV = 100 VDC
VOV = 450 VDC
RLS
2 MΩ
C L
X
S
F
D
DC
DC
Input
Voltage
Input
Voltage
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
S
L
D
S
L
C
S
D
CONTROL
CONTROL
C
C
X
F
-
-
PI-2617-050100
PI-2618-081403
Figure 16. Three Terminal Operation (LINE-SENSE and
EXTERNAL CURRENT LIMIT Features Disabled.
FREQUENCY Pin Tied to SOURCE or CONTROL Pin).
Figure 17. Line-Sensing for Under-Voltage, Overvoltage and Line
Feed-Forward.
+
+
VUV = RLS x IUV
VOV = IOV x RLS
2 MΩ
2 MΩ
For Value Shown
VUV = 100 VDC
For Values Shown
VOV = 450 VDC
RLS
RLS
DC
Input
Voltage
DC
Input
Voltage
22 kΩ
30 kΩ
1N4148
D
S
L
D
S
M
CONTROL
CONTROL
C
C
6.2 V
-
-
PI-2510-040501
PI-2620-040501
Figure 19. Linse-Sensing for Overvoltage Only (Under-Voltage
Disabled). Maximum Duty Cycle Reduced at Low Line
and Further Reduction with Increasing Line Voltage.
Figure 18. Line-Sensing for Under-Voltage Only (Overvoltage
Disabled).
+
+
ILIMIT = 100% @ 100 VDC
For RIL = 12 kΩ
ILIMIT
=
63% @ 300 VDC
ILIMIT = 69%
RLS
2.5 MΩ
For RIL = 25 kΩ
ILIMIT = 43%
See Figure 54b for
DC
Input
Voltage
DC
D
S
D
other resistor values
Input
(RIL)
CONTROL
X
CONTROL
Voltage
C
C
S
X
RIL
RIL
6 kΩ
-
-
PI-2624-040501
PI-2623-092303
Figure 20. Externally Set Current Limit.
Figure 21. Current Limit Reduction with Line Voltage.
M
12/04
15
POWERINT [ Power Integrations ]
