The Power Behind Performance

Rev 1.2 08/14

vicorpower.com

Applications Engineering: 800 927.9474

Page 9

The DC-DC Converter Chip Set

The PRM® and VTM® evaluation boards allow the user to select and configure the PRM®

and VTM to the unique application requirements of their system. By selecting the PRM

to accept the desired input voltage, one need only select the VTM to provide the desired

output voltage and plug them together if the nominal voltages are all that are required.

Refer to UG:0014 for information on the VTM evaluation board.

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

full load. 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-AL Customer Evaluation Boards are specified by add the suffix “-CB” to the

appropriate PRM model number.

Figure 5.

PRM-AL and VTM

Evaluation Boards

(plugged together)