Vicor Constant Current (CC) Demonstration Board User Manual
Page 9
UG:007
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Page 9
6.
Verify proper power supply to CC board connections.
7.
Connect DMM to measure the output voltage using the output Kelvin test points.
8.
Turn V
REF
(R10) potentiometer clockwise gently until it reaches its maximum value of
100 K which corresponds to
≈ 5 V depending on its tolerance. The potentiometer has
stops which indicate that it has been turned fully in one direction. Do not wind the
potentiometer past the stop, as this may damage the part.
9.
Turn V
MAX
(R8) potentiometer counterclockwise gently until it reaches its maximum value
of 5 K which corresponds to an output voltage of
≈ 30 V depending on its tolerance.
The potentiometer has stops which indicate that it has been turned fully clockwise /
counterclockwise. Do not wind the potentiometer past the stop as this may damage the part.
10. Connect DMM to measure V
REF
at TP5 with reference to SG at TP6.
11. Make sure (SW02) is in "close" position.
12. Turn on a fan if desired.
13. Raise the DC input voltage to the nominal value of 48 V as indicated on the
The output voltage should read approximately 30 V if the
potentiometer has been turned fully counterclockwise as directed in step 9.
14. Set the load in constant current mode to 50% of the PRM’s rated output (2.5 A for the
P048F048T24AL-CC). With the load in this setting, the circuit will have no control and will
drive the PRM to its maximum value provided that the load current is less than the
reference set point. This allows for adjusting the maximum PRM output voltage.
15. Turn the potentiometer (R8) clockwise to set the maximum PRM output voltage. When
setting the maximum PRM output, keep in mind that the CC feedback can drive the
output voltage up to this maximum limit in order to maintain the required current. Due to
component tolerances, turning (R8) fully clockwise can result in the circuit driving the PRM
above its maximum voltage. If this is done with no load, the PRM may be damaged.
Do not set the maximum PRM voltage above 55 V.
16. Turn off the electronic load
17. Turn the potentiometer V
REF
(R10) counterclockwise to lower the PRM output current set
point to the desired value. If V
REF
is not lowered to a reasonable value below the DC
current limit, the PRM will start in a fault condition when connected to a load. It will
remain in fault until the potentiometer V
REF
(R10) is turned counterclockwise to lower the
set reference. An undesirable clicking sound will be audible in this case. Although
continuous operation in this mode will not damage the unit, it is not recommended.
18. Decrease the input voltage to low line.
You have now verified the operation of the CC and set the desired output current and
maximum output voltage.