Toshiba is suing Taiwan's Powerchip Technology and three other firms charging infringement of its flash memory patents.

A Toshiba spokesman said that it wants Powerchip to write a cheque for $3.3 million in compensation in the case. It also wants an injunction to halt of the sale and manufacture of products that it says infringe its patents.

The Japanese company said that Powerchip, Powerflash Technology., Zentel Electronics. and C.T.C have been using NAND flash memory without a license to use technologies covered by Toshiba's Taiwan patents and that it decided to take the legal action as Powerchip Technology has ignored its notices.

Tosh has been getting a mite litigious of late. In March it filed suit against South Korea's SK Hynix seeking damages in a case over suspected theft of data related to its flash memory chip technology.

The company is not suffering as badly as others in the tech industry, last month it forecast record operating profit of $3.24 billion this business year as buoyant sales of power grid equipment and robust income from flash memory chips offset weakness in its nuclear reactor business.