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. 12, 2006
Filed:
Feb. 01, 2006
Satoshi Narumi, Itami, JP;
Hiroyuki Tamagawa, Itami, JP;
Satoshi Narumi, Itami, JP;
Hiroyuki Tamagawa, Itami, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
A motor drive apparatus includes a comparison circuit comparing voltages of 3-phase coil terminals and the voltage of a neutral point terminal of a 3-phase brushless motor to determine which voltage is higher/lower, a zero ampere current detection circuit detecting, based on the comparison result by the comparison circuit, that the coil current of a position detection phase becomes 0 A, a position detection circuit detecting a zero cross point of the voltage of the position detection phase based on the comparison result by the comparison circuit after the coil current becomes 0 A. Therefore, the zero cross point can be accurately detected without introducing a mask period.