DPA422-426
Typical Uses of FREQUENCY (F) Pin
+
+
DC
Input
DC
Input
Voltage
D
S
D
CONTROL
CONTROL
Voltage
C
C
S
F
F
-
-
PI-2655-071700
PI-2654-071700
Figure 10. 300 kHz Frequency Operation.
Figure 9. 400 kHz Frequency Operation.
Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins
+
+
VUV = IUV x RLS + VL (I
= I
)
L
UV
= I
VOV = IOV x RLS + VL (I
)
L
OV
619 k
1%
C
L
X
S
F
D
RLS
DC
Input
Voltage
DC
Input
Voltage
For RLS = 619 k
VUV = 33.3 V
VOV = 86.0 V
D
S
L
D
S
L
C
S
D
CONTROL
CONTROL
C
C
X
F
-
-
PI-2767-091302
PI-2766-070901
Figure 11. Three Terminal Operation (LINE-SENSE and EXTERNAL CURRENT
LIMIT Features Disabled. FREQUENCY Pin can be tied to SOURCE or
CONTROL Pin).
Figure 12. Line-Sensing for Undervoltage, Overvoltage and Line Feed-forward.
+
+
VOV = IOV x RLS
VL (I
+
VUV = RLS x IUV
+
590 k
1%
576 k
1%
VL (I
= I
)
= I
)
UV
L
OV
L
For Values Shown
VOV = 86.2 V
For Values Shown
VUV = 33.3 V
RLS
RLS
DC
Input
Voltage
DC
Input
Voltage
30 k
1%
42.2 k
1%
1N4148
D
L
D
S
L
CONTROL
CONTROL
C
C
6.2 V
S
-
-
PI-2853-091302
PI-2852-091302
Figure 14. Line-Sensing for Overvoltage Only (Undervoltage Disabled).
Maximum Duty Cycle will be reduced at Low Line.
Figure 13. Line-Sensing for Undervoltage Only (Overvoltage Disabled).
11
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Rev. T 12/12
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