Motor drive and magnetic disc apparatus
A back electromotive force detection circuit 12 incorporates an A/D conversion circuit 14 that converts the output from a differential amplifier circuit A 2 into a digital signal and an offset calculation circuit 15 that sets the resistance value of a variable resistor R 2 according to the output fr...
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Main Author | |
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Format | Patent |
Language | English |
Published |
04.01.2007
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Subjects | |
Online Access | Get full text |
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Summary: | A back electromotive force detection circuit 12 incorporates an A/D conversion circuit 14 that converts the output from a differential amplifier circuit A 2 into a digital signal and an offset calculation circuit 15 that sets the resistance value of a variable resistor R 2 according to the output from the AID conversion circuit 14. Based on the difference between the output from the AID conversion circuit 14 as obtained when the drive current fed to a motor coil L equals zero and the output from the A/D conversion circuit 14 as obtained when the drive current fed to a motor coil L equals a predetermined value, the offset calculation circuit 15 sets the resistance value of the variable resistor R 2. |
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Bibliography: | Application Number: US20060569239 |