Letter Agreement



 Exhibit 10.1 
 [Letterhead of Cypress] 
 December 21, 2006 
 PowerLight Corporation 
 2954 San Pablo Avenue 
 Berkeley, California 94702 
 To Whom It May Concern: 
 As an inducement to PowerLight Corporation (the “Company”), a California corporation, to execute the First Amendment to the
Agreement and Plan of Merger (the “Merger Agreement”; capitalized terms used but not otherwise defined herein have the meaning ascribed to them in the Merger Agreement); among SunPower Corporation, a Delaware corporation
and a majority owned Subsidiary of the undersigned (“Parent”), Pluto Acquisition Company LLC, a Delaware limited liability company and a wholly owned subsidiary of Parent, the Company and Thomas L. Dinwoodie, as
Shareholders’ Representative, pursuant to which, among other things, the Company will be merged with and into Merger Sub (the “Merger”), the undersigned hereby agrees that during the period commencing on the date of the
Merger Agreement and ending upon the earlier of (i) June 30, 2007 and (ii) 60 days after the date on which the Registration Statement on Form S-3 (the “Registration Statement”) to be filed with the Securities
and Exchange Commission (the “SEC”) by Parent in connection with the resale of Class A common stock to be issued in the Merger is declared effective by the SEC (the “Lock-up Period”), the
undersigned will not, without the prior written consent of the Company, directly or indirectly, (i) offer to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right
or warrant for the sale of, or otherwise dispose of or transfer any shares of Class B common stock, par value $0.001 per share (the “Parent Class B Common Stock”), of Parent owned by the undersigned as of the
date hereof, or acquired hereafter, or securities convertible into or exchangeable or exercisable for any shares of Parent Class B Common Stock, (ii) enter into, or cause any of its subsidiaries to enter into, a transaction which would
have the same effect, (iii) enter into any swap or other arrangement or transaction that transfers (including pursuant to the granting of any proxy), in whole or in part, directly or indirectly, any of the economic consequences of, or voting
rights arising from, ownership of such shares of Parent Class B Common Stock, whether any such aforementioned transaction is to be settled by delivery of the Parent Class B Common Stock or such other securities, in cash or otherwise,
(iv) exercise any right to convert such shares of Parent Class B Common Stock into any other security, or (v) publicly disclose the intention to make any such offer, sale, or disposition, to enter into any such transaction, swap, or other
arrangement or to exercise any right to convert; provided, however, that nothing set forth herein shall preclude the undersigned from pledging, or engaging in customary hedging transactions with respect to, Parent Class B Common Stock (the actions
described in clauses (i) through and including (v), being referred to as a “Disposition Transaction”). In addition, the undersigned agrees that, without the prior written consent of the Company, it will not, during the
Lock-Up Period, make any demand for the registration of any Parent Class B Common Stock or any security convertible into or exercisable or exchangeable for the Parent Class B Common Stock. 







 Furthermore, during the Lock-Up Period, the undersigned hereby agrees not to, and shall not instruct or
authorize its officers, directors, employees, financial advisors, representatives, agents, Subsidiaries and Affiliates to, directly or indirectly, (i) solicit any inquiry, proposal or offer from any Person in respect of a Disposition
Transaction; or (ii) enter into any agreement with any Person in respect of a Disposition Transaction. 
 In furtherance of the
foregoing, Parent and its transfer agent and registrar are hereby authorized to decline to make any transfer of shares of Parent Class B Common Stock if such transfer would constitute a violation or breach of this letter agreement. 

This letter agreement replaces the letter agreement, dated November 15, 2006, between the Company and the undersigned (the “Prior
Lock-Up Letter”) and the Prior Lock-Up Letter is hereby terminated. 
 This letter agreement shall be binding on the undersigned
and the successors, heirs, personal representatives and assigns of the undersigned. This letter agreement shall lapse and become null and void (and the Lock-Up Period shall terminate immediately) if the Merger Agreement terminates or is terminated.
This letter agreement shall be governed by, and construed in accordance with, the laws of the State of California. 
  

			
	Very truly yours,
	
	CYPRESS SEMICONDUCTOR CORP.
		
	By:	 	 /s/ Thurman J. Rodgers

	Name:	 	Thurman J. Rodgers
	Title:	 	CEO


  

			
	ACKNOWLEDGED AND AGREED
	
	As of December 21, 2006:
	
	POWERLIGHT CORPORATION
		
	By:	 	 /s/ Thomas L. Dinwoodie

	Name:	 	Thomas L. Dinwoodie
	Title:	 	Chief Executive Officer

  

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