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. 24, 2012
Filed:
Jan. 12, 2011
Kei Nagatomo, Kyoto, JP;
Hisato Takeuchi, Osaka, JP;
Shuuji Shibuya, Kyoto, JP;
Panasonic Corporation, Osaka, JP;
Abstract
In a crystal-oscillator circuit having a quartz crystal unit, further stabilization of output frequency change at a time of startup of the power supply is achieved. A crystal-oscillator circuit having a quartz crystal unit includes a first variable-capacitance element, which forms an oscillation loop with the quartz crystal unit, and a temperature compensation circuit which provides a first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit. In addition, the crystal-oscillator circuit includes a second variable-capacitance element group, and a time constant circuit which provides a time constant signal, which changes with a predetermined time constant, for the second variable-capacitance element group as a second control signal.