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:
Oct. 01, 2013
Filed:
Jan. 15, 2010
Chung-hsing Wang, Baoshan Township, TW;
Chih-chieh Chen, Launtang Taoyuan, TW;
Yi-wei Chen, Hsin-Chu, TW;
Chung-Hsing Wang, Baoshan Township, TW;
Chih-Chieh Chen, Launtang Taoyuan, TW;
Yi-Wei Chen, Hsin-Chu, TW;
Taiwan Semiconductor Manufacturing Company, Ltd., Hsin-Chu, TW;
Abstract
A system and method for observing threshold voltage variations are provided. A ring oscillator circuit comprises a plurality of inverters arranged in a sequential loop, a plurality of test circuits having devices under test, each coupled between a respective one of the inverters and a power supply. Each test circuit has a bypass field effect transistor (FET) having a first channel coupled between the power supply and a respective one of the inverters responsive to an individual enable signal, and a FET device under test having a second channel arranged in parallel to the first channel. A method is described for determining the threshold voltage of the device under test by disabling, for one of the inverters in the ring oscillator, the first FET device such that the device under test is coupled between the power supply and the respective inverter and affects the operating frequency of the ring oscillator.