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. 07, 1999
Filed:
Nov. 24, 1997
Henricus C Buthker, Mierlo, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An arrangement for generating drive signals for a multi-phase d.c. motor having a plurality of windings, comprising a multi-phase inverter (10) which supplies the drive signals to the windings of the motor in a manner such that the windings are recurrently energized by the drive signals in a given sequence. At least one of the windings is not supplied with a drive signal at least during predetermined free periods. A phase detector (40) which, under control of the multi-phase inverter, samples the back-emf signals of these windings in order to obtain a phase-error signal. A low-pass filter (42) generates a control signal dependence upon the phase-error signal, and a controllable oscillator (44) generates a frequency signal whose frequency depends on the control signal. The timing of the multi-phase inverter drive signals supplied to the motor windings depends on the frequency signal. A phase-locked loop is formed by the multi-phase inverter, the phase detector, the low-pass filter and the oscillator. A lock detector (70) which, on the basis of information about the frequency and phase of the phase-error signal and information about the frequency and phase of the frequency signal, determines whether or not the phase-locked loop is locked in phase.