vicorpower.com

Applications Engineering: 800 927.9474

Rev 1.1

Page 9

12/2013

For example, if a P048F048T24AL-CB and a V048F120T025-CB are mated as above, the input range

to the pair is 36 – 75 Vdc and the output would be 12 Vdc at no load decreasing by Iout x Rout of

Section 5d.

To provide for load regulation at the output of the VTM, the Adaptive Loop regulation mode should

be engaged. To activate this feature of the PRM-AL, the switch indicated CD (switch #4) should be set

to the ON position. The corresponding trim pot should be set to 19.2

Ω which will result in a total CD

to SG resistance of 39.2

Ω. This is the optimal value for the nominal PRM output voltage as set by the

fixed OS resistor installed on the board and activated by the OSF (switch #6) in the ON position. Be

certain to refer to the data sheets for the appropriate resistor values for your requirements.

To validate the functionality of the Adaptive Loop regulation, repeat the steps of 2.0 to 5.0 under the

section Baseline Test Procedure - PRM-CB except in this instance the output connections are to be

made to the VTM-CB output terminals. Both the PRM and VTM data sheets should be in hand. The

load current refers to the VTM output current ratings. Be certain to make the connections to the

supply and load prior to mating the boards to avoid stressing the connectors.

The PRM Adaptive Loop regulates the output of the VTM without sense lines. The Factorized Bus

voltage (Vf) may be moniored by using J02 on the PRM-CB board (Item 9) while increasing the load

current. Observe the Vf voltage increases with the load current, compensating for the insertion loss

due to the VTM output resistance.

VTM output voltages, which deviate from the nominal configuration, are available by changing the

output set point of the PRM as described in section 6 of this document and using the formula

described in the data sheet.

Ordering Information

The PRM and VTM Customer Evaluation Boards are specified by add the suffix “-CB” to the

appropriate PRM or VTM model number.

Go to http://www.vicorpower.com/contact-us for ordering information.