International Rectifier Corp. said Tuesday that its board has unanimously rejected a second, unsolicited buyout proposal from chip maker Vishay Intertechnology Inc., which has threatened a proxy battle over the matter.

Malvern, Pa.,-based Vishay this month raised its bid for the El Segundo power management chip maker to $23 per share, about $1.7 billion, up from the $21.22 first offered in August. International Rectifier said the offer “significantly undervalues” its future prospects.

“We believe that Vishay’s latest unsolicited proposal continues to represent an opportunistic attempt by Vishay to capture value that belongs to our shareholders,” said Chairman Richard Dahl in a statement.

In response to the rejection, Vishay said it proceeding with plans for a cash tender offer and has nominated three candidates for the company’s rescheduled annual shareholder meeting on Oct. 10.

“We are confident our all-cash premium proposal would provide International Rectifier stockholders with far greater value than what International Rectifier could achieve on its own in the foreseeable future,” said the company in a statement.

There has been bad blood between the companies ever since Vishay began questioning the value of a unit it acquired from International Rectifier last year.

Shares of International Rectifier were down 49 cents, or 2.4 percent, to $20.39 in morning trading on the New York Stock Exchange, after earlier falling more than 4 percent.