Piezoelectric transformer with monitor electrodes for sensing unbalanced vibration of the transformer
AssigneeNEC Corporation
InventorsHiroshi Sasaki, Kouichi Iguchi
Life of this patent
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Abstract
A piezoelectric transformer includes at least a pair of monitor electrodes for monitoring unbalanced vibration of the piezoelectric element. The transformer also has a plurality of input electrodes for a transformer input signal and a pair of output electrodes for a transformer output signal. While driven by the input signal to produce the output signal, the piezoelectric transformer produces a pair of monitor signal components at the monitor electrodes to individually indicate vibration components produced in the piezoelectric transformer collectively as a state of unbalanced operation of the transformer.
Claims14
A piezoelectric transformer comprising;
- a piezoelectric element and a plurality of power electrodes on said piezoelectric element subjecting said piezoelectric element to polarization, driving said piezoelectric element by a transformer input signal, and providing a transformer output signal;
- and a plurality of monitor electrodes offset from said power electrodes on said piezoelectric element monitoring unbalanced vibration of said piezoelectric element.
An abnormal operation detecting circuit and a piezoelectric transformer, comprising a piezoelectric element, a plurality of input electrodes for a transformer input signal, a pair of output electrodes for a transformer output signal, and a plurality of monitor electrodes for individually producing monitor signal components collectively as a monitor signal indicative of an unbalanced vibration of said piezoelectric element, and comparing means for comparing said monitor signal with a reference signal to produce a difference signal when the unbalanced vibration is objectionable.
A piezoelectric transformer with an abnormal operation detecting circuit, comprising:
- a piezoelectric element;
- transformer input electrodes connected to said piezoelectric element;
- transformer output electrodes connected to said piezoelectric element;
- a pair of monitor electrodes connected to said piezoelectric element, said pair of monitor electrodes being positioned symmetrically relative to one of said output electrodes;
- a differential amplifier connected to said pair of monitor electrodes for producing a difference signal indicating a difference between responses of said monitor electrodes that is indicative of abnormal operation of said transformer;
- a smoothing circuit for smoothing the difference signal;
- and
- a comparator connected to said smoothing circuit and to a reference signal to indicate an abnormal operation of the transformer.
Dependencies are inferred from the claim text.