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:
Sep. 25, 2012
Filed:
Jan. 29, 2010
Applicants:
Shigeru Hirata, Kyoto, JP;
Yoshifumi Shigmogaki, Kyoto, JP;
Inventors:
Shigeru Hirata, Kyoto, JP;
Yoshifumi Shigmogaki, Kyoto, JP;
Assignee:
Rohm Co., Ltd., Kyoto, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02P 6/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A rotation speed detection circuit includes an internal clock generation portion which receives an input of a period signal whose period varies in accordance with rotation speed of a motor and generates an internal clock signal having a predetermined number of pulses in one period of the period signal, and an internal clock counter portion which counts the number of pulses of the internal clock signal for a predetermined period every one period of the period signal and delivers a count value thereof as a digital data signal.