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:
Feb. 24, 2009
Filed:
May. 30, 2006
Souichi Toyama, Ebina, JP;
Yaichi Okubo, Ebina, JP;
Souichi Toyama, Ebina, JP;
Yaichi Okubo, Ebina, JP;
Hitachi Via Mechanics, Ltd., Ebina-shi, JP;
Abstract
A digital servo control unit which uses a D/A converter, which suppresses the spike-like pulsation superimposed on a current error signal inside a current control circuit, and which has control performance not lower than that in the background art even when a low-voltage and low-price power supply circuit is used. A first-order low pass filter acts on an analog signal output by the D/A converter, and a stabilizing compensation occurs for a phase delay caused by the first-order low pass filter. The first-order low pass filter is formed as a low pass filter having a cut-off frequency which is lower than a sampling frequency. The first-order low pass filter may be replaced by a notch filter having a cut-off frequency which is equal to a sampling frequency or which is equal to an integer multiple of a Nyquist frequency.