Vicor Westcor PFC MegaPAC Power Factor Corrected AC-DC Switchers - Manual (Page 21)

UG:105 vicorpower.com Applications Engineering: 800 927.9474 Page 21
External Trim (J2-1)
Output voltage can be trimmed using an optional factory-installed Trim potentiometer
or with the Trim pin (see Figure 11). The Trim potentiometer is located on the
ConverterPAC. If the Trim potentiometer has not been ordered, the Trim pin must be
used. When using the Trim pin, the Trim limits are determined by the DC/DC converter
used on the ConverterPAC. Maximum Trim ranges are 10% above the nominal
converter voltage and 50% below the nominal converter voltage (except 10 V, 12 V and
15 V outputs which are 10% below nominal) as measured from the output studs or
output connector of the power supply.
Note: The combined effects of module trim up, remote sense and dynamic load step may
cause the module to trip OVP. (See page 6 for information on restart).
The Trim pin on J2 can be used to control the output voltage. It is referenced to the
-Sense pin on J2 and can be controlled by either a resistor network or an external
voltage source. To increase an output voltage above its nominal, it is necessary to
increase the voltage at the Trim pin above the internal reference voltage (Vref). The
reverse is true to decrease an output voltage.
Note: Converters are sometimes pre-trimmed at the factory if a nonstandard output voltage is
requested. Standard voltages include 2 V, 3.3 V, 5 V, 10 V, 12 V, 15 V, 24 V, 28 V, and 48 V. If using a
nonstandard voltage, or if a ConverterPAC is ordered with a Trim option, the resistor calculations will
differ from those on page 22. Please consult the factory for assistance.
Figure 10.
Sense Leads
(Remote Sense)
Load
(Local Sense)
+P +Out
+Sense
-Sense
-P -Out
Use 22-24 AWG
Twisted Pair Wires