Power integrations TOPSwitch-HX Series Manual page 17

Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)
+
DC
Input
Voltage
D
6.2 V
S
-
Figure 20. Line Sensing for Undervoltage Only (Overvoltage Disabled).
+
DC
D
Input
Voltage
S
-
Figure 22. External Set Current Limit.
+
DC
D
Input
Voltage
S
-
Figure 24. Active-on (Fail Safe) Remote ON/OFF.
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V = R × I + V (I
UV LS UV V
4 MΩ
For Values Shown
V = 103.8 VDC
UV
R
LS
40 kΩ
V
CONTROL
C
PI-4720-120307
For R = 12 kΩ
IL
I = 61%
LIMIT
For R = 19 kΩ
IL
I = 37%
LIMIT
See Figure 55b for other
resistor values (R
IL
CONTROL
C
TOP259-261YN would
use the G pin as the
X
return for R .
IL
R
IL
PI-4722-021308
Q can be an optocoupler
R
output or can be replaced by
a manual switch.
TOP259-261YN would
use the G pin as the
return for Q .
R
CONTROL
C
X
ON/OFF
Q
R
47 KΩ
PI-2625-011008
+
= I )
V UV
DC
Input
Voltage
-
Figure 21. Line-Sensing for Overvoltage Only (Undervoltage Disabled). Maximum
Duty Cycle Reduced at Low Line and Further Reduction with
Increasing Line Voltage.
+
R
LS
DC
). Input
Voltage
-
Figure 23. Current Limit Reduction with Line Voltage.
+
DC
Input
Voltage
-
Figure 25. Active-on Remote ON/OFF with Externally Set Current Limit.
TOP252-262
V = I
OV OV
4 MΩ
For Values Shown
V = 457.2 VDC
OV
R LS
55 kΩ
1N4148
D V
CONTROL
C
S
I =
LIMIT
I =
LIMIT
2.5 MΩ
TOP259-261YN would
use the G pin as the
return for R
D
CONTROL
C
S X
R
IL
6 kΩ
Q can be an optocoupler
R
output or can be replaced
by a manual switch.
D
CONTROL
C
TOP259-261YN would
use the G pin as the
S X
return for Q
R
IL
Q
R
16 kΩ
× R + V (I = I )
LS V V OV
PI-4721-120307
100% @ 100 VDC
53% @ 300 VDC
.
IL
PI-4723-011008
For R = 12 kΩ
IL
I = 61%
LIMIT
For R = 19 kΩ
IL
I = 37%
LIMIT
.
R
ON/OFF
PI-4724-011008
17
Rev. J 08/16