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.

Date of Patent:
Oct. 20, 2015

Filed:

Jan. 22, 2014
Applicant:

Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;

Inventors:

Kiyoshi Kato, Kanagawa, JP;

Takuro Ohmaru, Kanagawa, JP;

Yasuyuki Takahashi, Miyagi, JP;

Assignee:

Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 11/22 (2006.01); G11C 11/24 (2006.01);
U.S. Cl.
CPC ...
G11C 11/22 (2013.01); G11C 11/24 (2013.01);
Abstract

Provided is a memory device with reduced overhead power. A memory device includes a first circuit retaining data in a first period during which a power supply voltage is supplied; a second circuit saving the data retained in the first circuit in the first period and retaining the data saved from the first circuit in a second period during which the power supply voltage is not supplied; and a third circuit saving the data retained in the second circuit in the second period and retaining the data saved from the second circuit in a third period during which the power supply voltage is not supplied. The third circuit includes a transistor in which a channel formation region is provided in an oxide semiconductor film and a capacitor to which a potential corresponding to the data is supplied through the transistor.


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