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:
May. 09, 2017
Filed:
Jan. 27, 2016
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Masashi Tsubuku, Kanagawa, JP;
Kazuaki Ohshima, Kanagawa, JP;
Masashi Fujita, Tokyo, JP;
Daigo Shimada, Kanagawa, JP;
Tsutomu Murakawa, Kanagawa, JP;
Semiconductor Energy Laboratory Co., LTD., Kanagawa-ken, JP;
Abstract
A semiconductor device that can measure a minute current. The semiconductor device includes a first transistor, a second transistor, a node, and a capacitor. The first transistor includes an oxide semiconductor in a channel formation region. The node is electrically connected to a gate of the second transistor and a first terminal of the capacitor. The node is brought into an electrically floating state by turning off the first transistor after a potential Vis supplied. Change in a potential Vof the node over time is expressed by Formula (1). In Formula (1), t is elapsed time after the node is brought into the electrically floating state, τ is a constant with a unit of time, and β is a constant greater than or equal to 0.4 and less than or equal to 0.6.