TABLE OF CONTENTS

	ITEM 1(A).      NAME OF ISSUER:
	ITEM 1(B).      ADDRESS OF ISSUER’S PRINCIPAL EXECUTIVE OFFICES:
	ITEM 2(A).      NAME OF PERSON FILING:
	ITEM 2(B).      ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE:
	ITEM 2(C).      CITIZENSHIP:
	ITEM 2(D)      TITLE OF CLASS OF SECURITIES:
	ITEM 2(E)      CUSIP NUMBER:
	ITEM 3.           IF THIS STATEMENT IS FILED PURSUANT TO RULE 13D-1(B), OR 13D-2(B) OR (C), CHECK WHETHER THE PERSON FILING IS A:
	ITEM 4.           OWNERSHIP.
	ITEM 5.           OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.
	ITEM 6.           OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.
	ITEM 7.           IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.
	ITEM 8.           IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.
	ITEM 9.           NOTICE OF DISSOLUTION OF GROUP.
	ITEM 10.           CERTIFICATION.
SIGNATURE

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Table of Contents

ITEM 1(A).      NAME OF ISSUER:

                          Vicor Corporation

ITEM 1(B).      ADDRESS OF ISSUER’S PRINCIPAL EXECUTIVE OFFICES:

                          25 Frontage Road, Andover, MA 01810

ITEM 2(A).      NAME OF PERSON FILING:

                          Patrizio Vinciarelli

ITEM 2(B).      ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE:

                          Vicor Corporation, 25 Frontage Road, Andover, MA 01810

ITEM 2(C).      CITIZENSHIP:

                          United States

ITEM 2(D)      TITLE OF CLASS OF SECURITIES:

                          Common Stock, par value $.01 per share

ITEM 2(E)      CUSIP NUMBER:

                          925815 10 2

ITEM 3.           IF THIS STATEMENT IS FILED PURSUANT TO RULE 13D-1(B), OR 13D-2(B) OR (C), CHECK WHETHER THE                          PERSON FILING IS A:

                          Not applicable

 

ITEM 4.           OWNERSHIP.

               Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

               (a) Amount beneficially owned: 20,986,203

As of December 31, 2004, Mr. Vinciarelli was the beneficial owner of 9,962,555 shares of Vicor Corporation Common Stock (which number includes 32,001 shares which Mr. Vinciarelli has the right to acquire upon the exercise of options to purchase Common Stock within 60 days of December 31, 2004). Additionally, he owned 11,023,648 shares of Vicor Corporation Class B Common Stock, which may be converted at any time into 11,023,648 shares of Common Stock.

               (b) Percent of class:

                          50.9%

               (c) Number of shares as to which such person has:

                          (i) Sole power to vote or to direct the vote: 20,986,203

                          (ii) Shared power to vote or to direct the vote: 0

                          (iii) Sole power to dispose or to direct the disposition of: 20,986,203

                          (iv) Shared power to dispose or to direct the disposition of: 0

ITEM 5.           OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

                          Not applicable.

ITEM 6.           OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

                          Not applicable.

 

ITEM 7.           IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING                          REPORTED ON BY THE PARENT HOLDING COMPANY.

                          Not applicable.

ITEM 8.           IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

                          Not applicable.

ITEM 9.           NOTICE OF DISSOLUTION OF GROUP.

                          Not applicable.

ITEM 10.           CERTIFICATION.

                          Not applicable.

 

SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: January 31, 2005	/s/ Patrizio Vinciarelli
	Name:	Patrizio Vinciarelli
	Title:	Chairman of the Board, President and Chief Executive Officer