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. 06, 2015

Filed:

Mar. 24, 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 11/40 (2006.01); G11C 11/4091 (2006.01); G11C 11/401 (2006.01); G11C 11/4074 (2006.01);
U.S. Cl.
CPC ...
G11C 11/4091 (2013.01); G11C 11/401 (2013.01); G11C 11/4074 (2013.01);
Abstract

The first circuit has a function of retaining data in a first period during which a power supply voltage is supplied. The second circuit has functions of 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 application of the power supply voltage is stopped. The third circuit has functions of 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 application of the power supply voltage is stopped. The second circuit is capable of being written with the data for a shorter time than the third circuit. The third circuit is capable of maintaining the data for a longer time than the second circuit.


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