Invention Grant
- Patent Title: Motor drive device and electronic timepiece
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Application No.: US15214695Application Date: 2016-07-20
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Publication No.: US09785117B2Publication Date: 2017-10-10
- Inventor: Yohei Kawaguchi , Fumiaki Ochiai , Yuta Saito
- Applicant: CASIO COMPUTER CO., LTD.
- Applicant Address: JP Tokyo
- Assignee: CASIO COMPUTER CO., LTD.
- Current Assignee: CASIO COMPUTER CO., LTD.
- Current Assignee Address: JP Tokyo
- Agency: Chen Yoshimura LLP
- Priority: JP2015-156501 20150806
- Main IPC: G04C3/14
- IPC: G04C3/14 ; H02P8/02 ; H02P8/32 ; H02P8/12

Abstract:
A motor drive device includes a driver unit configured to be connected to a stepping motor, and a controller connected to the driver unit. The controller causes the driver unit to output a drive pulse to the stepping motor for causing the stepping motor to rotate stepwise in a prescribed rotation direction. The controller detects, through the driver unit, a current induced by a counter-electromotive force generated in the stepping motor in response to the drive pulse. The controller causes the driver unit to apply a counter pulse having the same electrical polarity as the drive pulse to the stepping motor so as to suppress an amount of the current induced by the counter-electromotive force when the stepping motor is not rotating in response to the drive pulse so that the amount of the induced current detectably differs between when the stepping motor is rotating and not rotating.
Public/Granted literature
- US20170038736A1 MOTOR DRIVE DEVICE AND ELECTRONIC TIMEPIECE Public/Granted day:2017-02-09
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