CONTROL FUNCTIONS - PC PIN
Module Enable/Disable
The module may be disabled by pulling PC below 2.3 V with
respect to the –Input. This may be done with an open collector
transistor, relay, or optocoupler. Multiple converters may be
disabled with a single transistor or relay either directly or via
“OR’ing” diodes. See Figure 1.
Primary Auxiliary Supply
At 5.7 V, PC can source up to 1.5 mA. In the example shown
in Figure 3, PC powers a module enabled LED.
Module Alarm
The module contains “watchdog” circuitry which monitors
input voltage, operating temperature and internal operating
parameters. In the event that any of these parameters are
outside of their allowable operating range, the module will
shut down and PC will go low. PC will periodically go high
and the module will check to see if the fault (as an example,
overtemperature) has cleared. If the fault has not been cleared,
PC will go low again and the cycle will restart. The SC pin
will go low in the event of a fault and return to its normal
state after the fault has been cleared. See Figures 2 and 4.
+In
PC
+IN
PC
PR
1M
5.7 Vdc
(0-3 mA)
SW1
Auto
Restart
Input Undervoltage
Input Overvoltage
[a]
Over Temperature
Module Faults
+OUT
50
Ω
2-20 ms typ.
f(V
IN
)
SW2
SW3
1K
SC
Disable
PR
–In
6K
1.23
Vdc
–IN
SW1, 2, & 3 shown
in "Fault" position
–OUT
Disable = PC <2.3V
[a]
Not applicable for 300 Vdc Input family
Figure 1
—
Module enable/disable.
Figure 2
—
PC/SC module alarm logic.
+In
PC
"Module
Enabled"
4kΩ
Fault
PC
5.7V
40μs typ.
PR
–In
SC
1.23V
2-20ms typ.
Figure 3
—
LED on-state indicator.
Figure 4
—
PC/SC module alarm timing.
Optocoupler
+In
PC
+OUT
Comparator
SC
4kΩ
PR
–In
Alarm
1.00 V
–OUT
Figure 5
—
Isolated on-state indicator.
Vicor Corp.
Tel: 800-735-6200, 978-470-2900 Fax: 978-475-6715
Figure 6
—
Secondary side on-state indicator.
48V Micro Family
Rev. 7.5
Page 8 of 13
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