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:
Jul. 14, 1998
Filed:
Sep. 26, 1996
Haruhiko Fujii, Tokyo, JP;
Ando Electric Co., Ltd., Tokyo, JP;
Abstract
An object of the invention is to provide a variable delay circuit having a desired optional resolution. A variable delay section 24 is provided with paths A and B which carry signals input to an input terminal 21 to an output terminal 22, and a selection section for switching the paths A and B in accordance with a select signal. Ring oscillators 25 and 29 have oscillation periods which are x times and y times the delay time of the respective paths A and B. Phase comparison circuits 27 and 31 respectively compare, the phase of a first clock signal and the output from the ring oscillator 25, and the phase of a second clock signal and the output from the ring oscillator 29. Delay time control circuits 28 and 32 then respectively control the oscillation periods of the ring oscillators 25 and 29 so as to be equal to the respective periods of the first clock signal and the second clock signal, based on the phase comparison results, and control the delay times of the paths A and B.