-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000901484-09-000002.txt : 20090123
<SEC-HEADER>0000901484-09-000002.hdr.sgml : 20090123
<ACCEPTANCE-DATETIME>20090123092957
ACCESSION NUMBER:		0000901484-09-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090121
FILED AS OF DATE:		20090123
DATE AS OF CHANGE:		20090123

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VINCIARELLI PATRIZIO
		CENTRAL INDEX KEY:			0000901484

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-18277
		FILM NUMBER:		09540525

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		(978) 749-3404

	MAIL ADDRESS:	
		STREET 1:		C/O VICOR CORPORATION
		STREET 2:		25 FRONTAGE ROAD
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			VICOR CORP
		CENTRAL INDEX KEY:			0000751978
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC COMPONENTS, NEC [3679]
		IRS NUMBER:				042742817
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		25 FRONTAGE ROAD
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810
		BUSINESS PHONE:		9784702900

	MAIL ADDRESS:	
		STREET 1:		25 FRONTAGE RD
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-01-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000751978</issuerCik>
        <issuerName>VICOR CORP</issuerName>
        <issuerTradingSymbol>vicr</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000901484</rptOwnerCik>
            <rptOwnerName>VINCIARELLI PATRIZIO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VICOR CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>25 FRONTAGE ROAD</rptOwnerStreet2>
            <rptOwnerCity>ANDOVER</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01810</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-01-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4006</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9667829</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 15, 2008.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Richard J. Nagel, Jr., Attorney in Fact for Patrizio Vinciarelli</signatureName>
        <signatureDate>2009-01-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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