<SEC-DOCUMENT>0000833640-17-000059.txt : 20170202
<SEC-HEADER>0000833640-17-000059.hdr.sgml : 20170202
<ACCEPTANCE-DATETIME>20170202164612
ACCESSION NUMBER:		0000833640-17-000059
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170201
FILED AS OF DATE:		20170202
DATE AS OF CHANGE:		20170202

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			POWER INTEGRATIONS INC
		CENTRAL INDEX KEY:			0000833640
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				943065014
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5245 HELLYER AVE
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95138
		BUSINESS PHONE:		4084149200

	MAIL ADDRESS:	
		STREET 1:		5245 HELLYER AVE
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95138

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BALAKRISHNAN BALU
		CENTRAL INDEX KEY:			0001182405
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23441
		FILM NUMBER:		17568921

	MAIL ADDRESS:	
		STREET 1:		C/O POWER INTEGRATIONS
		STREET 2:		5245 HELLYER AVE
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95138
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-02-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000833640</issuerCik>
        <issuerName>POWER INTEGRATIONS INC</issuerName>
        <issuerTradingSymbol>POWI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182405</rptOwnerCik>
            <rptOwnerName>BALAKRISHNAN BALU</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5245 HELLYER AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95138</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-02-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>21615</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>211042</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-02-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3176</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>72.052</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>181605</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">For fiscal year 2016, the reporting person was granted a Performance Stock Unit.   The Performance Stock Unit vests based on Power Integrations satisfaction of certain performance conditions. The performance conditions for 2016 were met, resulting in vesting of the Performance Stock Unit.</footnote>
        <footnote id="F2">Represents the automatic sale of stock to cover the tax liability associated with the vesting of a Restricted Stock Award.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: /s/ Eric Verity Attorney In Fact For: Balu Balakrishnan</signatureName>
        <signatureDate>2017-02-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
