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:
Dec. 30, 1986
Filed:
Dec. 03, 1985
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
A driving circuit for a brushless DC motor having a small amount of torque ripple comprises a magnetic pole position detecting circuit for detecting positions of magnetic poles of a rotor magnet and delivering polyphase signals indicating the positions, a rectifier adder circuit for producing a sum of positive or negative portions of the polyphase signals from the magnetic pole position detecting circuit, a first error amplifier for adjusting a gain of the magnetic pole position detecting circuit to make an output signal of the rectifier adder circuit to be proportional to an instruction signal, a power supply circuit for supplying currents to armature coils in response to the polyphase signals, a modulating signal producing circuit for producing a modulating signal synchronized with the rotation of the motor, and a second error amplifier for adjusting a gain of the power supply circuit to make the currents supplied to the armature coils to be proportional to the modulating signal.