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. 08, 1998
Filed:
Jul. 19, 1996
Hitachi, Ltd., Tokyo, JP;
Abstract
A motor drive method and apparatus for reducing noise of a motor. The motor drive apparatus includes first, second and third half bridge circuits. Each of the first, second and third half bridge circuits includes a first transistor which is adapted to form a current path between a first operational potential and an output terminal thereof and a second transistor which is adapted to form a current path between a second operational potential and the output terminal thereof. Each of the output terminals are connected to the corresponding drive coil of a motor. Each of the first and second transistors includes a control terminal to which a control signal is supplied. The motor drive apparatus detects a counter-induced voltage of the drive coil corresponding to the second half bridge circuit by supplying control signals to the first and second transistors thereof for making each current path therein a non-conducting state, and for forming current paths in the first transistor of the first half bridge circuit and in the second transistor of the third half bridge circuit respectively. Further the motor drive apparatus cuts off the current path of the first transistor in the first half bridge circuit, forms it and cuts it off again by supplying a control signal thereto after start of supplying a control signal for forming the current path of the first transistor in the second half bridge circuit. A control signal for forming the current path is supplied to the control terminal of the second transistor in the third half bridge circuit.