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. 06, 1992
Filed:
Dec. 12, 1990
Applicant:
Inventor:
Jun Hirotomi, Tokyo, JP;
Assignee:
Seiko Instruments Inc., , JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
318116 ; 310316 ;
Abstract
An ultrasonic motor which has a driving circuit monitoring a current flowing through a piezoelectric element of the ultrasonic motor, shaping and amplifying the current, and feeding back as a control voltage to a voltage-controlled oscillating circuit, whose output is used to generate a drive signal for the ultrasonic motor. This ultrasonic motor driving circuit is provided with a rotation halt detector that detects when the ultrasonic motor stops its rotation. According to an output signal of the rotation halt detector, a reference voltage for the rectification and amplification is variably controlled.