Generator for producing ultrasonic energy

Claim 2

In combination ultrasonic transducer means whose impedance varies as a function of its loading, oscillator circuit means including amplifying means having at least a control electrode and first and second output electrodes, means for connecting said transducer means to one of said output electrodes to receive driving current from said amplifying means, frequency responsive circuit means including at least one reactive circuit element connected to the output electrode of said amplifying means to serve as the load impedance therefor, means coupling energy from said frequency responsive circuit means to said control electrode to provide a positive feedback signal to produce and sustain oscillations of said amplifying means, and means connected to said frequency responsive circuit means for changing the load impedance seen by said other output electrode during a given portion of each cycle of its oscillations to increase the power delivered to the transducer.

Claim 3

The combination of claim 1 wherein said means for changing the load impedance of the frequency responsive circuit means includes means responsive to the current through said amplifying means to lower the Q of the frequency responsive circuit means when current is flowing through said amplifying means.

Claim 4

The combination of claim 2 wherein said ultrasonic transducer means includes means forming a frequency responsive circuit.

Claim 5

The combination of claim 1 wherein said frequency responsive circuit means includes a tuned resonant circuit, said means for changing the load impedance seen by said other output electrode comprising a diode and a first means having a resistive component which are connected to said resonant circuit, said diode becoming conductive during said give portions of each cycle of oscillation of said amplifying means to place said first means in circuit with said resonant circuit means to lower the impedance of the latter, said diode being non-conductive during the remainder of each cycle of oscillation of said amplifying means.

Claim 6

The combination of claim 2 wherein said frequency responsive circuit means includes a tuned resonant circuit, said means for changing the load impedance of said circuit comprising a diode and a first means having a resistive component which are connected to said resonant circuit, said diode becoming conductive during said given portions of each cycle of oscillation of said amplifying means to place said first means in circuit with said resonant circuit means to lower the Q of the latter, said diode being non-conductive during the remainder of each cycle of oscillation of said amplifying means.

Claim 7

The combination of claim 1 wherein said means for connecting said transducer to said amplifying means connects it in series with said one electrode and a point of reference potential so that the current through said amplifying means is proportional to the current through said transducer means and a first voltage is present between said one output electrode and said point of reference potential which is proportional to the voltage across said transducer, means for connecting said frequency responsive circuit means to said other electrode so that a second voltage is present thereon which is proportional to the current through said amplifying means, said coupling means applying said second voltage to said control electrode so that said first and second voltages are vectorially additive with respect to the operation of said amplifying means to produce said oscillations.

Claim 8

In the combination of claim 6 wherein said three electrode amplifying means is a semiconductor device having an emitter, a collector and a base electrode which are respectively said first and second output electrodes and said control electrode.

Claim 9

In the combination of claim 7 wherein said transducer is connected to said emitter electrode and said frequency responsive circuit means for applying the second voltage to said base electrode comprises tuned feedback circuit means connected between the collector and base electrodes.

Claim 10

In combination an ultrasonic transducer means whose impedance varies as a function of its loading, oscillator circuit means including amplifying means having at least a control electrode and first and second output electrodes, means for connecting said transducer means in series between a point of reference potential and said first output electrode so hat the current through said amplifying means is proportional to the current through said transducer means and a first voltage appears between said first output electrode and said point of reference potential which is proportional to the voltage across said transducer, and means connected to said second output electrode for producing a second voltage proportional to the current through said amplifying means and for applying said second voltage to said control electrode so that said first and second voltages are vectorially additive with respect to the operation of said amplifying means to produce and sustain oscillations, said last named means comprising a tune resonant circuit including a transformer having a primary and a secondary winding, a pair of series connected capacitors connected in parallel across said secondary winding and means connected between the junction of said pair of capacitors and said control electrode for supplying said second voltage to said control electrode.

Claim 11

In combination an ultrasonic transducer means whose impedance varies as a function of its loading, oscillator circuit means including amplifying means having at least a control electrode and first and second output electrodes, means for connecting said transducer means in series between a point of reference potential and said first output electrode so hat the current through said amplifying means is proportional to the current through said transducer means and a first voltage appears between said first output electrode and said point of reference potential which is proportional to the voltage across said transducer, and means connected to said second output electrode for producing a second voltage proportional to the current through said amplifying means and for applying said second voltage to said control electrode so that said first and second voltages are vectorially additive with respect to the operation of said amplifying means to produce and sustain oscillations, said last named means comprising a tune resonant circuit including a transformer having a primary and a secondary winding, a pair of series connected capacitors connected in parallel across said secondary winding and means connected between the junction of said pair of capacitors and said control electrode for supplying said second voltage to said control electrode.

Claim 12

The combination of claim 9 further comprising means connected to said frequency responsive circuit means for changing the impedance load that it presents to said second output electrode during a given portion of each cycle of its oscillations.

Claim 13

The combination of claim 1 wherein said tuned resonant circuit means comprises a transformer having primary and secondary windings, said means for changing the impedance load presented by said tuned resonant circuit means being connected to said primary winding, said means for coupling energy to said control electrode comprising a pair of series connected capacitors connected across said secondary winding, and means connected between the junction of said pair of capacitors and said control electrode to supply said positive feedback signal to said control electrode.

Claim 14

The combination of claim 7 further comprising diode means connected between said collector and base electrodes to prevent the potential at the base electrode from exceeding the potential at the collector electrode.

Claim 15

In combination an ultrasonic transducer means whose impedance varies as a function of its loading, said ultrasonic transducer means including a plurality of magnetostrictive elements and a single coil in proximity thereto for supplying driving current to said elements, oscillator circuit means including amplifying means having at least a control electrode and first and second output electrodes, means for connecting said single coil of said transducer means in series between a point of reference potential and said first output electrode so that the current through said amplifying means if proportional to the current through the coil of said transducer means and a first voltage appears between said first output electrode and said point of reference potential which is proportional to the voltage across said transducer, circuit means connected to said second output electrode for producing a second voltage proportioNal to the current through said amplifying means and for applying said second voltage to said control electrode so that said first and second voltages are vectorially additive with respect to the operation of said amplifying means to produce and sustain oscillations, circuit means comprising at least in part the load impedance for said second output electrode and including first means responsive to the conduction level of said amplifying means for varying the load impedance presented by said circuit means.

Claim 16

In combination an ultrasonic transducer means whose impedance varies as a function of its loading, said ultrasonic transducer means including a plurality of magnetostrictive elements and a single coil in proximity thereto for supplying driving current to said elements, oscillator circuit means including amplifying means having at least a control electrode and first and second output electrodes, means for connecting said single coil of said transducer means in series between a point of reference potential and said first output electrode so that the current through said amplifying means if proportional to the current through the coil of said transducer means and a first voltage appears between said first output electrode and said point of reference potential which is proportional to the voltage across said transducer, circuit means connected to said second output electrode for producing a second voltage proportioNal to the current through said amplifying means and for applying said second voltage to said control electrode so that said first and second voltages are vectorially additive with respect to the operation of said amplifying means to produce and sustain oscillations, circuit means comprising at least in part the load impedance for said second output electrode and including first means responsive to the conduction level of said amplifying means for varying the load impedance presented by said circuit means.

Claim 17

The combination of claim 13 wherein circuit last means comprises a tuned resonant circuit including a transformer having a primary and a secondary winding, a pair of series connected capacitors connected in parallel across said secondary winding and means connected between the junction of said pair of capacitors and said control electrode for supplying said second voltage to said control electrode.

Claim 18

The combination of claim 13 further comprising an additional impedance element, said circuit means including a tuned resonant circuit, and said first means including second means for placing said additional impedance element in circuit with said tuned resonant circuit.

Claim 19

The combination of claim 15 wherein said tuned resonant circuit includes a transformer having a primary winding with one end connected to the said second output electrode, said second means and said additional impedance element connected in series across at least a portion of said transformer.

Claim 20

The combination of claim 16 wherein said second means is a diode and said diode and said additional impedance element are connected in series across the primary winding of the transformer.