CONTROL FUNCTIONS - PC PIN
Module Enable/Disable
Module Alarm
The module may be disabled by pulling PC below 2.3V 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.
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.
Primary Auxiliary Supply
At 5.7V, PC can source up to 1.5mA. In the example shown in
Figure 3, PC powers a module enabled LED.
Input Undervoltage
Input Overvoltage
+In
PC
+Out
+In
PC
Overtemperature
Auto
Restart
Module Faults
SW1
+S
SC
–S
2-20ms typ.
50Ω
f (V )
IN
SW1, 2, & 3
shown in
"Fault" position
1K
SW2
SW3
PR
–In
PR
–In
Disable
5.7Vdc
(0-3mA)
1.23
Vdc
–Out
6K
Disable = PC <2.3V
Figure 1—Module enable/disable.
Figure 2—PC/SC module alarm logic.
+In
PC
Fault
PC
40µs typ.
5.7V
4kΩ
"Module
Enabled"
PR
–In
1.23V
2-20ms typ.
SC
Figure 3—LED on-state indicator.
Figure 4—PC/SC module alarm timing.
+In
PC
Optocoupler
+Out
+S
SC
–S
4kΩ
Alarm
PR
–In
1.00V
–Out
Figure 5—Isolated on-state indicator.
Figure 6—Secondary side on-state indicator.
Vicor Corp. Tel: 800-735-6200, 978-470-2900 Fax: 978-475-6715
V375A28C600A DC-DC Converter
Rev. 5.2
Page 4 of 8
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