Piezoelectric device and circuitry
The present disclosure provides a device having a circuit. The circuit includes at least one boost converter receiving power from an energy source, a square wave driver in series with the boost converter, an inductor in series with the square wave driver for converting a square wave to a sinusoidal wave, and a piezoelectric transducer in series with the inductor, the piezoelectric transducer connectable to a load. The device further includes a phase-locked loop coupled to the circuit to determine a resonance frequency of the piezoelectric transducer when the piezoelectric transducer is connected to the load.
1. A device, comprising:
a circuit, comprising:
at least one boost converter configured to receive power from an energy source;
a square wave driver configured to receive power from the boost converter and to generate a high voltage square wave;
a distally mounted piezoelectric transducer driven by the square wave driver, and connectable to a load;
first and second grounded diodes arranged back-to-back and configured in parallel with each other, the diodes connected in series with the transducer and arranged to form a junction between the transducer and ground; and
a voltage comparator having a first input connected to the junction, and an output that indicates phase of current through the transducer as a voltage; and
coupled to the circuit, a phase-locked loop in a feedback loop, the phase-locked loop comprising a low pass filter, a voltage-controlled oscillator (VCO), and a phase comparator having a first input for receiving from the VCO a voltage that indicates a drive voltage phase and having a second input for receiving the voltage comparator output voltage,
whereby when the transducer is connected to the load the phase-locked loop synchronizes the current phase and the drive voltage phase to determine a resonance frequency of the transducer.
2. The device of claim 1 , wherein the energy source is a direct current rechargeable battery, and wherein the energy source is integral to the circuit.
3. The device of claim 2 , wherein the circuit further comprises a second boost converter powered from the direct current battery, and optionally wherein the output of the second boost converter provides power to the phase-locked loop.
4. The device of claim 1 , wherein the circuit further comprises a capacitor in parallel with the transducer to suppress at least a 3rd harmonic mode of vibration of the transducer.
5. The device of claim 1 , wherein the phase-locked loop is configured to synchronize drive voltage to the resonance frequency of the transducer when the transducer is connected to the load; and
wherein said device comprises a frequency limiting circuit coupled to the phase-locked loop.
6. The device of claim 1 , further comprising a fluid pump, optionally wherein the fluid pump is selected from the group consisting of an elastomeric infusion pump and a piezoelectric pump, and optionally wherein said pump is capable of producing flow rates between 0.01 ml-20 ml per minute to a treatment site.
7. The device of claim 1 , wherein the load is a treatment tip for a procedure selected from the group consisting of a dental procedure and a medical procedure.
8. The device of claim 1 , wherein the transducer is of 40-60 mm in length and has:
a loaded resonance frequency of between 25-50 kHz,
a backmass characterized by rings of varying radii,
a stack comprising between 2 and 8 piezoelectric discs electrically connected in parallel and mechanically connected in series, and
a tapered horn;
wherein said circuit is capable of producing an applied voltage waveform of between 100 and 800 volts peak-to-peak.
9. The device of claim 1 , further comprising an inductor in series with the square wave driver.
10. The device of claim 9 , wherein the circuit further comprises a capacitor in series with the inductor.
11. A cordless handheld ultrasonic device comprising:
a device body having a distal end for coupling to at least one treatment tip; and
a circuit within the device body, the circuit comprising:
at least one boost converter configured to receive power from an energy source;
a square wave driver configured to receive power from the boost converter and to generate a high voltage square wave;
a distally mounted piezoelectric transducer driven by the square wave driver;
first and second grounded diodes arranged back-to-back and configured in parallel with each other, the diodes connected in series with the transducer and arranged to form a junction between the transducer and ground,
a voltage comparator having a first input connected to the junction, and an output that indicates phase of current through the transducer as a voltage; and
coupled to the circuit, a phase-locked loop in a feedback loop, the phase-locked loop comprising a low pass filter, a voltage controlled oscillator, and a phase comparator having a first input for receiving from the voltage-controlled oscillator a voltage that indicates a drive voltage phase and having a second input for receiving the voltage comparator output voltage to determine a resonance frequency of the piezoelectric transducer when the piezoelectric transducer is connected to the at least one treatment tip.
12. The cordless handheld ultrasonic device of claim 11 , wherein the circuit further comprises an energy source, the at least one boost converter in series with the energy source and wherein the circuitry further comprises a second boost converter in series with the energy source.
13. The cordless handheld ultrasonic device of claim 12 , wherein the output of the second boost converter is an input to the phase-locked loop.
14. The cordless handheld ultrasonic device of claim 12 , wherein the energy source is a rechargeable battery.
15. The cordless handheld ultrasonic device of claim 11 , wherein the piezoelectric transducer is connectable to a treatment tip for a procedure selected from the group consisting of a dental procedure and a medical procedure.
16. The cordless handheld ultrasonic device of claim 11 , wherein the phase-locked loop is configured to synchronize drive voltage to the resonance frequency of the transducer when the transducer is connected to the load; and wherein said device comprises a frequency limiting circuit coupled to the phase-locked loop.
17. The cordless handheld ultrasonic device of claim 11 , further comprising a fluid pump, optionally wherein the fluid pump is selected from the group consisting of an elastomeric infusion pump and a piezoelectric pump, and optionally wherein said pump is capable of producing flow rates between 0.01 ml-20 ml per minute to a treatment site.
18. The device of claim 11 , wherein the transducer is of 40-60 mm in length and has:
a loaded resonance frequency of between 25-50 kHz,
a backmass characterized by rings of varying radii,
a stack comprising between 2 and 8 piezoelectric discs electrically connected in parallel and mechanically connected in series, and
a tapered horn;
wherein said circuit is capable of producing an applied voltage waveform of between 100 and 800 volts peak-to-peak.
19. The device of claim 11 , further comprising an inductor in series with the square wave driver.
20. The cordless handheld ultrasonic device of claim 19 , further comprising a capacitor in series with the inductor.
21. A device, comprising:
a circuit, comprising:
at least one boost converter configured to receive power from an energy source;
a square wave driver configured to receive power from the boost converter and to generate a high voltage square wave;
a distally mounted piezoelectric transducer driven by the square wave driver and, connectable to a load;
first and second grounded diodes arranged back-to-back and configured in parallel with each other, the diodes connected in series with the transducer and arranged to form a junction between the transducer and ground; and
a voltage comparator having a first input connected to the junction, and an output that indicates phase of current through the transducer as a voltage; and
a feedback loop coupled to the circuit to determine a resonance frequency of the piezoelectric transducer when the piezoelectric transducer is connected to the load.
22. The device of claim 21 , wherein the energy source is a direct current rechargeable battery, and wherein the energy source is integral to the circuit.
23. The device of claim 22 , wherein the circuit further comprises a second boost converter powered from the direct current battery, and optionally wherein the output of the second boost converter provides power to the feedback loop.
24. The device of claim 21 , wherein the circuit further comprises a capacitor in parallel with the piezoelectric transducer to suppress at least a 3rd harmonic mode of vibration of the piezoelectric transducer.
25. The device of claim 21 , wherein the feedback loop is configured to synchronize drive voltage to the resonance frequency of the transducer when the transducer is connected to the load; and wherein said device comprises a frequency limiting circuit coupled to the feedback loop.
26. The device of claim 21 , further comprising a fluid pump, optionally wherein the fluid pump is selected from the group consisting of an elastomeric infusion pump and a piezoelectric pump, and optionally wherein said pump is capable of producing flow rates between 0.01 ml-20 ml per minute to a treatment site.
27. The device of claim 21 , wherein the load is a treatment tip for a procedure selected from the group consisting of a dental procedure and a medical procedure.
28. The device of claim 21 , wherein the transducer is of 40-60 mm in length and has:
a loaded resonance frequency of between 25-50 kHz,
a backmass characterized by rings of varying radii,
a stack comprising between 2 and 8 piezoelectric discs electrically connected in parallel and mechanically connected in series, and
a tapered horn;
wherein said circuit is capable of producing an applied voltage waveform of between 100 and 800 volts peak-to-peak.
29. The device of claim 21 , further comprising an inductor in series with the square wave driver.
30. The device of claim 29 , wherein the circuit further comprises a capacitor in series with the inductor.