The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 13, 2002
Filed:
Nov. 21, 2000
Hiroshi Hatae, Saitama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention includes a logic circuit block operated in synchronism with a clock signal, power supply switches which supply power to the logic circuit block, and a switch control circuit which controls the power supply switches. The switch control circuit switch-controls the power supply switches so as to bring a period shorter than the cycle of the clock signal to an on operation period in synchronism with a clock signal. When the logic circuit block is supposed to be activated in synchronism with a clock signal having a frequency lower than a clock signal frequency for defining the maximum operation speed of the logic circuit block, the logic circuit block does not develop a malfunction theoretically if capable of operation for each cycle of the clock signal at least only for a time interval defined by the clock signal frequency of the maximum operation speed. Since the supplying of operating power to the logic circuit block is cut off according to the clock signal frequency except for a period necessary for a circuit operation, leak current that will flow through each turned-off transistor in the meantime, can be significantly reduced.