Patent ID: 7683562
Filing Date: 2010-03-23
Classification: H02P

Abstract:
1. A waveform shaping circuit comprising: a first comparator generating and outputting a first pulse signal from a first-phase rotational position signal; a second comparator generating and outputting a second pulse signal from a second-phase rotational position signal; a third comparator generating and outputting a third pulse signal from a third-phase rotational position signal; a first chattering preventing circuit receiving said first and second pulse signals and preventing chattering of a first output, said first chattering preventing circuit holding a level of said first output changed in response to a first rising of said first pulse signal when a level of said second pulse signal is a prescribed level, and holding a level of said first output changed again in response to a first falling of said first pulse signal when a level of said second pulse signal is a level opposite to said prescribed level; a second chattering preventing circuit holding a level of a second output changed in response to a first rising of said second pulse signal when a level of said third pulse signal is said prescribed level, and holding a level of said second output changed again in response to a first falling of said second pulse signal when a level of said third pulse signal is a level opposite to said prescribed level; and a third chattering preventing circuit holding a level of a third output changed in response to a first rising of said third pulse signal when said first pulse signal is at said prescribed level, and holding a level of said third output changed again in response to a first falling of said third pulse signal when said second pulse signal is at a level opposite to said prescribed level.