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:
Apr. 14, 2009
Filed:
Apr. 17, 2003
Matthias Wendt, Würselen, DE;
Hans Steinbusch, Landgraaf, DE;
Gerhard Diefenbach, Aachen, DE;
Christian Reichinger, Neutraubling, DE;
Matthias Wendt, Würselen, DE;
Hans Steinbusch, Landgraaf, DE;
Gerhard Diefenbach, Aachen, DE;
Christian Reichinger, Neutraubling, DE;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A starting-process controller for starting a piezomotor, having a voltage-controlled oscillator, a power output stage, and a resonant converter. The oscillator generates the control signals required for the power output stage and the resonance converter converts the stepped output voltage from the power output stage into a sinusoidal voltage at the output. The resonance converter drives the piezomotor with the voltage. The motor current that flows when the piezomotor is driven is measured and compared with the phase of the drive voltage in a phase comparator. The comparison output signal is a measure of the phase difference at the time between current and voltage. A phase-locked loop filter smoothes the phase-difference signal for controling the oscillator. The controller includes a start-assisting circuit element that fixes the output voltage from the phase-locked loop filter at start-up and thus applies a constant voltage to the input of the voltage-controlled oscillator.