Ultrasonic motor drive apparatus having surge and oscillation suppressing member
First Claim
1. An ultrasonic motor drive apparatus comprising:
- a d.c. power source;
a transformer having a primary coil and a secondary coil, the primary coil having a first end connected to the power source and a second end;
a switching device having an input terminal, an output terminal and a control terminal, the input terminal being connected to the second end of the primary coil and the output terminal connected to a ground, the switching device being for turning on and off an electrical current to the primary coil in response to a control signal applied to the control terminal; and
a suppression member connected between the output terminal of the switching device and the ground to suppress surge voltages and high frequency oscillations.
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Accused Products
Abstract
An ultrasonic motor drive apparatus includes a transformer having a primary coil and a secondary coil which drives a piezoelectric body of an ultrasonic motor. One end and the other end of the primary coil are connected to the drains of MOSFETS. The gates of the MOSFETs are connected to receive switching signals to alternately turn on and off electrical currents which flow in the primary coil. The sources of the MOSFETs are connected to the ground through ferrite beads, respectively. The ferrite bead generates a counter electromotive voltage so that the surge voltage which develops on the drain of the MOSFET at the time of turning off of the MOSFET is suppressed and high frequency oscillations are suppressed.
17 Citations
10 Claims
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1. An ultrasonic motor drive apparatus comprising:
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a d.c. power source;
a transformer having a primary coil and a secondary coil, the primary coil having a first end connected to the power source and a second end;
a switching device having an input terminal, an output terminal and a control terminal, the input terminal being connected to the second end of the primary coil and the output terminal connected to a ground, the switching device being for turning on and off an electrical current to the primary coil in response to a control signal applied to the control terminal; and
a suppression member connected between the output terminal of the switching device and the ground to suppress surge voltages and high frequency oscillations. - View Dependent Claims (2, 3)
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4. An apparatus for an electric device comprising:
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a d.c. power source;
a transformer having a primary coil and a secondary coil, the primary coil having a first end connected to the power source and a second end, and the secondary coil being connected to the electric device;
a switching device connected between the second end of the primary coil and a reference potential, the switching device being for turning on and off an electrical current to the primary coil in response to a control signal applied thereto; and
an inductive member connected between the switching device and the reference potential to slow down a turning-off of the switching device thereby to reduce surge voltages. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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Specification