UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported) March 7, 2011

INTERNATIONAL RECTIFIER CORPORATION

(Exact Name of Registrant as Specified in Charter)

101 North Sepulveda Boulevard, El Segundo, California 90245

(Address of Principal Executive Offices) (Zip Code)

(310) 726-8000

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 1.01.  Entry into a Material Definitive Agreement

By means of a Current Report on Form 8-K filed with the Securities and Exchange Commission on February 25, 2011 (the “February 25, 2011 8-K”), International Rectifier Corporation (“IRF”) previously reported that on February 24, 2011, IRF entered into a definitive agreement (the “Agreement”) to acquire CHiL Semiconductor Corporation (“CHIL”) for $75 million in cash subject to a working capital adjustment, by means of a merger of a subsidiary of IRF with and into CHIL, with CHIL becoming a wholly-owned subsidiary of IRF.  The Agreement and the transaction contemplated by the Agreement are more fully described in the February 25, 2011 8-K.

On March 7, 2011, the transaction contemplated by the Agreement was closed.

Item 7.01.  Regulation FD Disclosure.

On March 7, 2011, IRF issued a press release announcing the close of the transaction related to the Agreement. A copy of that press release is attached as Exhibit 99.1 to this Current Report on Form 8-K.

The information in this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1, will not be treated as filed for the purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section. This information will not be incorporated by reference into a filing under the Securities Act of 1933, or into another filing under the Exchange Act, unless that filing expressly refers to specific information in this report. The furnishing of the information in this Item 7.01 of this report is not intended to, and does not, constitute a representation that such furnishing is required by Regulation FD or that the information in this Item 7.01 is material investor information that is not otherwise publicly available.

Item 9.01. Financial Statements and Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX

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