Electronic watch
US8841875B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Oct 6, 2010 |
| Grant date | Sep 23, 2014 |
| Priority date | — |
| Expiry date | May 19, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P8/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Provided is an electronic watch capable of, even if an indicating hand having a large moment of inertia is used, accurately determining success and failure of rotation. The electronic watch detects rotation by using a first detection mode determination circuit (12) and a second detection mode determination circuit (13). In the electronic watch, a timing counter (14) for measuring a time after an output of a normal drive pulse is followed by a detection pulse selection circuit (151) provided as changing means for changing a width or a frequency of a detection pulse in accordance with an output time of the detection pulse. The detection pulse detects the rotation and simultaneously serves as an electromagnetic brake for a rotor (10). The electromagnetic brake for the rotor (10) is controlled by changing the width or the frequency of the detection pulse in a predetermined period, thereby achieving an accurate rotation detection. Alternatively, the setting of the width or the frequency of the detection pulse may be changed in accordance with a determination result in a first detection mode, an output voltage of a power supply, and a driving power of the normal drive pulse, instead of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.