-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 HRIDMzKLefFH8PHpgFQUpyzTthHH6olpl4Q/9vkgLgRSq2buJm3VaRQnYPIV7mQr
 HNlaW5Hwr+uGHZ5EAo+kAQ==

<SEC-DOCUMENT>0000833640-03-000040.txt : 20030507
<SEC-HEADER>0000833640-03-000040.hdr.sgml : 20030507
<ACCEPTANCE-DATETIME>20030506174252
ACCESSION NUMBER:		0000833640-03-000040
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030505
FILED AS OF DATE:		20030507

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:			MORRISH ANDREW
		CENTRAL INDEX KEY:			0001182409
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23441
		FILM NUMBER:		03684914

	BUSINESS ADDRESS:	
		STREET 1:		C/O POWER INTEGRATIONS
		STREET 2:		5245 HELLYER AVE
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95138
		BUSINESS PHONE:		4084148868

	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>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

<documentType>4</documentType><periodOfReport>2003-05-05</periodOfReport>
<issuer><issuerCik>0000833640</issuerCik>
        <issuerName>POWER INTEGRATIONS INC</issuerName>
<issuerTradingSymbol>POWI</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001182409</rptOwnerCik>
            <rptOwnerName>MORRISH ANDREW</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
<reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Vp Strategic Market</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-05-05</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8125</value></transactionShares><transactionValue><value>11.9</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>8125</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></
ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-05-05</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8125</value></transactionShares><transactionValue><value>23.58</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><derivativeSecurity><securityTitle><value>Non-Qualified Stock Option(right to buy)</value></securityTitle><conversionOrExercis
ePrice><value>11.9</value></conversionOrExercisePrice><transactionDate><value>2003-05-05</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8125</value></transactionShares><transactionValue><value>23.58</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2002-08-05</value></exerciseDate><expirationDate><value>2012-08-05</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>8125</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>109992</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directO
rIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes/><ownerSignature><signatureName>Rober Lelieur Attorney in Fact</signatureName><signatureDate>2003-05-06</signatureDate></ownerSignature></ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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