TOP242-249
Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins
+
DC
Input
Voltage
D
L
CONTROL
C
CLXS F D
CS D
-
S
XF
PI-2617-050100
Figure 16. Three Terminal Operation (LINE-SENSE and
EXTERNAL CURRENT LIMIT Features Disabled.
FREQUENCY Pin can be tied to SOURCE or
CONTROL Pin).
+
DC
Input
Voltage
VUV = IUV x RLS
VOV = IOV x RLS
For RLS = 2 MΩ
RLS 2MΩ VUV = 100 VDC
VOV = 450 VDC
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
L
CONTROL
C
-
S
PI-2618-040501
Figure 17. Line-Sensing for Under-Voltage, Overvoltage and
Line Feed Forward.
+
DC
Input
Voltage
6.2 V
2 MΩ
VUV = RLS x IUV
For Value Shown
RLS VUV = 100 VDC
22 kΩ
D
M
CONTROL
C
-
S
PI-2510-040501
Figure 18. Line-Sensing for Under-Voltage Only (Overvoltage
Disabled).
+
DC
Input
Voltage
2 MΩ
VOV = IOV x RLS
For Values Shown
RLS
VOV = 450 VDC
30 kΩ
D
L
CONTROL
C
1N4148
-
S
PI-2620-040501
Figure 19. Line-Sensing for Overvoltage Only (Under-Voltage
Disabled). Maximum Duty Cycle will be reduced at
Low Line.
+
DC
Input
Voltage
For RIL = 12 kΩ
ILIMIT = 69%
For RIL = 25 kΩ
ILIMIT = 43%
See fig. 55 for other
D
resistor values (RIL)
CONTROL
C
S
X
RIL
-
Figure 20. Externally Set Current Limit.
PI-2623-040501
16 E
7/01
August 8, 2000
+
RLS 2.5 MΩ
ILIMIT = 100% @ 100 VDC
ILIMIT = 63% @ 300 VDC
DC
Input
Voltage
D
CONTROL
C
S
X
RIL
-
6 kΩ
PI-2624-040501
Figure 21. Current Limit Reduction with Line Voltage.