Voltage transforming devices utilizing piezoelectric elements

Claim 2

A voltage transforming device comprising an elongated piezoelectric transformer having a driving region, a generating region, a feedback electrode and a first driving electrode applied on one side of said driving region, a second driving electrode applied to the other side of said driving region, and a high voltage output electrode applied to the end surface of said generating region; an oscillation transistor with its base electrode connected to said feedback electrode; a high frequency inductive transformer having at least one intermediate tap connected between the collector electrode of said transistor and one of said driving electrodes for resonating with the capacitance of said driving electrodes at the vibration frequency of said piezoelectric transformer; means to connect an intermediate tap of said high frequency inductive transformer to the base electrode of said transistor; and a DC source connected to said tap and said base electrode, the output proportional to the displacement amplitude of said piezoelectric element derived from said feedback electrode being fed back to said base electrode to determine the most suitable vibration frequency of said piezoelectric transformer to cause said transistor to oscillate at said frequency.

Claim 3

The voltage transforming device according to claim 1 wherein said hIgh frequency transformer is provided with a plurality of intermediate taps and wherein the connection between said base electrode and said taps is adapted to be changed to vary the driving voltage impressed across said driving electrodes by changing the impedance ratio of said inductive transformer.

Claim 4

The voltage transforming device according to claim 2 wherein a variable resistor is connected between said feedback electrode and said base electrode to control the valve of the high output voltage appearing at said output electrode of said piezoelectric element.

Claim 5

A voltage transforming device comprising an elongated piezoelectric element having a driving region, a generating region, a feedback electrode and a first driving electrode applied on one side of said driving region, a second driving electrode applied to the other side of said driving region, and a high voltage output electrode applied to the end surface of said generating region; an oscillation transistor with its emitter electrode connected to said feedback electrode; a high frequency inductive transformer connected between one of said driving electrodes and the base electrode of said transistor for resonating with the capacitance of said driving electrodes at the vibration frequency of said piezoelectric transformer, said high frequency transformer being provided with a plurality of intermediate taps, means to selectively connect one of said intermediate taps to the collector electrode of said transistor, means to connect one end of said high frequency inductive transformer to the base electrode of said transistor and a DC source connected to said one end of said high frequency inductive transformer and said base electrode, the output proportional to the displacement amplitude of said piezoelectric element appearing at said feedback electrode being fed back to said emitter to determine the most stable vibration frequency of said piezoelectric element thus causing said transistor to oscillate at said frequency.

Claim 6

A voltage transforming device comprising an elongated piezoelectric element having a driving region, a generating region, a feedback electrode and a first driving electrode applied on one side of said driving region, a second driving electrode applied to the other side of said driving region, and a high voltage output electrode applied to the end surface of said generating region; an oscillation transistor with its emitter electrode connected to said feedback electrode; a high frequency inductive transformer connected between one of said driving electrodes and the base electrode of said transistor for resonating with the capacitance of said driving electrodes at the vibration frequency of said piezoelectric transformer, said high frequency transformer being provided with a plurality of intermediate taps, means to selectively connect one of said intermediate taps to the collector electrode of said transistor, means to connect one end of said high frequency inductive transformer to the base electrode of said transistor and a DC source connected to said one end of said high frequency inductive transformer and said base electrode, the output proportional to the displacement amplitude of said piezoelectric element appearing at said feedback electrode being fed back to said emitter to determine the most stable vibration frequency of said piezoelectric element thus causing said transistor to oscillate at said frequency.