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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Bibliographic Details
Main Author DAIO MITSUAKI
Format Patent
LanguageEnglish
Published 04.01.2007
Subjects
CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORSOR DYNAMO-ELECTRIC CONVERTERS
CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
ELECTRICITY
GENERATION
INFORMATION STORAGE
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER
PHYSICS
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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.
Bibliography:Application Number: US20060569239