US3708701A - Apparatus for driving piezoelectric transformers - Google Patents

Apparatus for driving piezoelectric transformers Download PDF

Info

Publication number
US3708701A
US3708701A US00125702A US3708701DA US3708701A US 3708701 A US3708701 A US 3708701A US 00125702 A US00125702 A US 00125702A US 3708701D A US3708701D A US 3708701DA US 3708701 A US3708701 A US 3708701A
Authority
US
United States
Prior art keywords
resonance circuit
switching element
frequency
pulse
resonance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00125702A
Other languages
English (en)
Inventor
T Kawada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denki Onkyo Co Ltd
Original Assignee
Denki Onkyo Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Denki Onkyo Co Ltd filed Critical Denki Onkyo Co Ltd
Application granted granted Critical
Publication of US3708701A publication Critical patent/US3708701A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/802—Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
    • H10N30/804—Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits for piezoelectric transformers

Definitions

  • ABSTRACT In apparatus for driving a transducer including a pair of electrodes there are provided a resonance circuit comprised by an inductance and a capacitance connected in parallel and connected across the input electrodes of the transducer, and means for supplying a periodic pulse current of narrow width to the resonance circuit thereby driving the piezoelectric transducer by the energy delivered by the resonance circuit.
  • a piezoelectric transducer comprises a solid rod or annular ring of sintered lead titanate zirconate or the like and the rod or ring is provided with two polarized regions, one formed with input electrodes and the other an output electrode.
  • An AC driving voltage of the same or approximately the same frequency as the mechanical resonance frequency of the rod or ring is impressed across input electrodes to generate a high AC voltage at the output terminal.
  • Such a piezoelectric transducer can not generate the high voltage at a desired voltage step-up ratio unless it is driven by a driving voltage having the same or approximately the same frequency as its mechanical resonance frequency. Further, it is essential to use a driving voltage of rectangular waveform in order to increase the voltage step-up ratio and to stabilize the frequency of the driving voltage in order to stabilize the voltage step-up ratio. For this reason, the driving apparatus for the piezoelectric transducer are required to satisfy various requirements described above.
  • Another object of this invention is to provide a novel driving apparatus for a piezoelectric transducer according to which the transducer can operate at a high voltage step-up ratio.
  • Further object of this invention is to provide a novel apparatus for driving a piezoelectric transducer which is suitable to use as a high voltage generating device for a television receiver.
  • apparatus for driving a piezoelectric transducer including a pair of input electrodes, said apparatus comprising a resonance circuit connected across the input electrodes, and means for supplying a periodic pulse current of narrow width to the resonance circuit, the resonance circuit including an inductance and a capacitance which are connected in parallel thereby driving the piezoelectric transducer by the energy delivered by the resonance circuit.
  • FIG. 1 shows a connection diagram of one example of the apparatus for driving a piezoelectric transducer constructed according to the principle of this invention
  • FIG. 2 shows waveforms of various elements shown in FIG. 1;
  • FIG. 3 is a curve showing the relationship between the output voltage V and the frequency f ⁇ of the driving pulse utilized to drive the piezoelectric transducer shown in FIG. 1
  • FIG. 4 shows a connection diagram of a modified embodiment of this invention and FIG. 5 shows waveforms to explain a method of improving the efficiency of transformation.
  • FIG. 1 of the accompanying drawing there is shown a piezoelectric transducer 1 including a pair of input electrodes 11 and 12 applied to the opposite surfaces of one end of a ceramic rod and an output electrode 13 applied to the end surface of the other end.
  • the driving voltage for the piezoelectric transducer 1 is generated by a resonance circuit 2 comprising an inductor 21 and a capacitor 22 connected in parallel therewith.
  • One terminal of the resonance circuit 2 is connected to one input electrode 11 whereas the other terminal is connected to the other input electrode 12 via a source of DC, a battery 3, for example.
  • a switching element 4 which may be a vacuum tube or a transistor.
  • a NPN type transistor is used with its collector electrode connected to the input terminal 11 of the piezoelectric transducer through a diode 5.
  • the cathode electrode of diode 5 is connected to'the collector electrode of the transistor.
  • an input circuit network 6 comprising an impedance matching transformer, for example, is connected between a source of pulse 7 or a source of a horizontal synchronizing pulse signal where the piezoelectric transducer is used for a television receiver and the base and emitter electrodes of the transistor 4.
  • One of the output terminals of the input circuit network and the emitter electrode of the transistor are connected to the input electrode 12 of the piezoelectric transducer.
  • the high voltage appearing at the output voltage may be converted into a high voltage direct current by means of any type of rectifier.
  • a voltage multiplying type rectifier circuit 8 comprising capacitors 85, 86 and 87 and diodes 81 through 84 which are connected as shown.
  • the output of the rectifier circuit is impressed across a load 9 which corresponds to the anode electrode of the cathode ray tube of a television receiver, for instance.
  • the piezoelectric transistor 1 is designed to have a mechanical resonance frequency which is the same or substantially the same as the repetitive frequency or its integer multiple of the horizontal synchronizing pulse signal supplied to the input of transistor 4.
  • the particular resonance frequency of the piezoelectric transfonner which is to be matched with the frequency or its integer multiple of the horizontal synchronizing signal can be readily determined by the proper selection of the configuration or dimension of the piezoelectric transducer.
  • the values of inductor 21 and capacitor 22 of the resonance circuit 2 are selected to cause the same to resonate at a frequency equal to or nearly equal to the mechanical resonance frequency of the piezoelectric transducer. This relationship among the frequencies of the piezoelectric transducer, resonance circuit and the horizontal synchronizing pulse signalis an important factor in order to stably drive the piezoelectric transducer.
  • the purpose of the diode 5 connected between the collector electrode of transistor 4 and the resonance circuit 2 is to prevent the oscillation current generated by resonance circuit 2 from being short circuited by the transistor, particularly by its base and collector electrodes.
  • the diode 5 is effective to prevent this short circuiting and provides a damping effect when the transistor is driven.
  • the resonance voltage V having a sinusoidal waveform is applied across the input terminals 1 1 and 12 of the piezoelectric transducer l.
  • the waveform of this driving voltage is shown by FIG. 2c.
  • the piezoelectric transducer 1 Upon receival of this resonance voltage V, the piezoelectric transducer 1 will vibrate at its natural mechanical resonance frequency to produce a high voltage sine wave voltage at its output electrode 13 as shown in FIG. 2d.
  • the output voltage is an extremely stable sine wave voltage because the driving voltage V, is derived from the resonance circuit 2.
  • the output voltage is rectified by the rectifier network 8 and is then applied to load 9.
  • a periodic pulse of a narrow width such as a horizontal synchronizing pulse signal, and having a frequency equal to or nearly equal to the mechanical resonance frequency of the piezoelectric transducer 1 is impressed upon the transistor 4, energy will be stored in the inductor 21 of resonance circuit 2 while the transistor is conducting.
  • the energy stored in inductor 21 is discharged through capacitor 22 thus creating a sine wave oscillation voltage which is applied across the input electrodes of the transducer.
  • FIG. 3 shows a relationship between the frequency of synchronizing pulse and the output voltage V of the piezoelectric transducer driven by the driving apparatus shown in FIG. 1.
  • the curve plotted in FIG. 3 shows that the output voltage reaches a maximum when the frequency f, of the synchronizing pulse substantiatly coincides with the mechanical resonance frequency of the piezoelectric transducer.
  • the novel driving apparatus utilizing the resonance circuit described above is suitable for driving a piezoelectric transducer adapted to drive a large load.
  • the output power of the resonance circuit 2 increases when the inductance of the inductor is decreased and the capacitance of the capacitor is increased.
  • the output power is limited by the maximum collector current of the transistor and the maximum current of diode 5.
  • FIGS. 5a and 5b are waveforms to explain the method of improving the transforming efficiency of the novel apparatus. These curves show the phase relationship between the driving pulse V, for transistor 4 and the output voltage V, from the resonance circuit 2. Upon application of the resonance voltage V, in the same direction as the collector voltage of the transistor 4 as shown in FIG. 5a, transistor 4 will operate with a large collector loss thus decreasing the efficiency of transformation. If the width of the driving pulse V, were selected such that the pulse is impressed at an instant when the resonance voltage V, becomes zero or negative with respect to the collector voltage of the transistor the efficiency of transformation will be improved substantially.
  • novel driving apparatus can also be used for any piezoelectric transducer designed to generate a high voltage.
  • Apparatus for driving a piezoelectric transformer including a pair of input electrodes, said apparatus comprising: a resonance circuit connected across said input electrodes, said resonance circuit including an inductance and a capacitance which are connected in parallel and said resonance circuit having a resonance frequency equal to or substantially equal to the mechanical resonance frequency or its integer multiple of said piezoelectric transformer; means for supplying periodic current pulses to said resonance circuit at a.
  • said pulse supplying means comprising a switching element having a control electrode and means for applying a periodic pulse current signal to said control electrode to render said switching element periodically conductive at the frequency of said pulse supplying means; and a diode connected between said switching element and said resonance circuit to prevent said switching element from stopping oscillation of said resonance circuit when said switching element is not conducting.
  • the apparatus according to claim 1 including a source of DC to energize said resonance circuit and wherein said diode is connected between said switching element and said resonance circuit with a polarity forward with respect to the polarity of said source.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
US00125702A 1970-03-20 1971-03-18 Apparatus for driving piezoelectric transformers Expired - Lifetime US3708701A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45023735A JPS5037367B1 (en, 2012) 1970-03-20 1970-03-20

Publications (1)

Publication Number Publication Date
US3708701A true US3708701A (en) 1973-01-02

Family

ID=12118551

Family Applications (1)

Application Number Title Priority Date Filing Date
US00125702A Expired - Lifetime US3708701A (en) 1970-03-20 1971-03-18 Apparatus for driving piezoelectric transformers

Country Status (2)

Country Link
US (1) US3708701A (en, 2012)
JP (1) JPS5037367B1 (en, 2012)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4232241A (en) * 1977-05-26 1980-11-04 Kabushiki Kaisha Seikosha Electric circuit for driving a piezoelectric vibrator
EP0706306A3 (en) * 1994-10-05 1997-12-10 Nec Corporation A hardware arrangement and method of driving a piezo-electric transformer
WO2000010120A1 (en) * 1998-08-13 2000-02-24 Electronics For Imaging, Inc. Transducer signal waveshaping system
US6054796A (en) * 1998-07-16 2000-04-25 Face International Corp. Positive feedback resonant transducer circuit
US6133672A (en) * 1998-02-27 2000-10-17 Nec Corporation Driving method of piezoelectric transformer and driving circuit for the same
WO2001029957A1 (en) * 1999-10-19 2001-04-26 Alcatel Switched power supply converter with a piezoelectric transformer
US6438008B1 (en) * 1995-12-15 2002-08-20 Yehoshua Mandelcorn Transient current suppression circuitry for reducing noise of battery floating across input of voltage polarity switch
US6571643B1 (en) 1998-08-13 2003-06-03 Electronics For Imaging, Inc. Ultrasound speed measurement of temperature and pressure effects
US20110277968A1 (en) * 2010-05-14 2011-11-17 Foxconn Technology Co., Ltd. Airflow generator and heat dissipation device incorporating the same

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1866267A (en) * 1927-01-24 1932-07-05 Wired Radio Inc Production of oscillations from piezo electric crystals
US2240293A (en) * 1938-03-23 1941-04-29 Rca Corp Piezoelectric filter
US2522924A (en) * 1946-07-03 1950-09-19 Branson Instr Supersonic inspection apparatus
US2852676A (en) * 1955-02-15 1958-09-16 Ivan L Joy Voltage train generating device
US2975354A (en) * 1956-11-30 1961-03-14 Gen Electric Electrical conversion apparatus
US3117768A (en) * 1960-11-21 1964-01-14 Branson Instr Ultrasonic transducers
US3152295A (en) * 1961-05-01 1964-10-06 Bendix Corp Pulsed tank circuit magneto-or electrostrictive device excitation
US3427568A (en) * 1967-01-30 1969-02-11 Edwards High Vacuum Int Ltd Transistorised oscillators
US3432691A (en) * 1966-09-15 1969-03-11 Branson Instr Oscillatory circuit for electro-acoustic converter
US3435368A (en) * 1965-03-06 1969-03-25 Hattori Tokeiten Kk Low frequency piezoelectric crystal oscillator having a single driving circuit
US3598909A (en) * 1967-07-25 1971-08-10 Matsushita Electric Ind Co Ltd A high-voltage generator circuit configuration utilizing a ceramic transformer

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1866267A (en) * 1927-01-24 1932-07-05 Wired Radio Inc Production of oscillations from piezo electric crystals
US2240293A (en) * 1938-03-23 1941-04-29 Rca Corp Piezoelectric filter
US2522924A (en) * 1946-07-03 1950-09-19 Branson Instr Supersonic inspection apparatus
US2852676A (en) * 1955-02-15 1958-09-16 Ivan L Joy Voltage train generating device
US2975354A (en) * 1956-11-30 1961-03-14 Gen Electric Electrical conversion apparatus
US3117768A (en) * 1960-11-21 1964-01-14 Branson Instr Ultrasonic transducers
US3152295A (en) * 1961-05-01 1964-10-06 Bendix Corp Pulsed tank circuit magneto-or electrostrictive device excitation
US3435368A (en) * 1965-03-06 1969-03-25 Hattori Tokeiten Kk Low frequency piezoelectric crystal oscillator having a single driving circuit
US3432691A (en) * 1966-09-15 1969-03-11 Branson Instr Oscillatory circuit for electro-acoustic converter
US3427568A (en) * 1967-01-30 1969-02-11 Edwards High Vacuum Int Ltd Transistorised oscillators
US3598909A (en) * 1967-07-25 1971-08-10 Matsushita Electric Ind Co Ltd A high-voltage generator circuit configuration utilizing a ceramic transformer

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4232241A (en) * 1977-05-26 1980-11-04 Kabushiki Kaisha Seikosha Electric circuit for driving a piezoelectric vibrator
EP0706306A3 (en) * 1994-10-05 1997-12-10 Nec Corporation A hardware arrangement and method of driving a piezo-electric transformer
US6438008B1 (en) * 1995-12-15 2002-08-20 Yehoshua Mandelcorn Transient current suppression circuitry for reducing noise of battery floating across input of voltage polarity switch
US6133672A (en) * 1998-02-27 2000-10-17 Nec Corporation Driving method of piezoelectric transformer and driving circuit for the same
US6054796A (en) * 1998-07-16 2000-04-25 Face International Corp. Positive feedback resonant transducer circuit
US20030196476A1 (en) * 1998-08-13 2003-10-23 Wood Robert P. Ultrasound speed measurement of temperature and pressure
US6118205A (en) * 1998-08-13 2000-09-12 Electronics For Imaging, Inc. Transducer signal waveshaping system
US6571643B1 (en) 1998-08-13 2003-06-03 Electronics For Imaging, Inc. Ultrasound speed measurement of temperature and pressure effects
WO2000010120A1 (en) * 1998-08-13 2000-02-24 Electronics For Imaging, Inc. Transducer signal waveshaping system
US6786102B2 (en) 1998-08-13 2004-09-07 Luidia Inc. Ultrasound speed measurement of temperature and pressure
WO2001029957A1 (en) * 1999-10-19 2001-04-26 Alcatel Switched power supply converter with a piezoelectric transformer
US6738267B1 (en) 1999-10-19 2004-05-18 Alcatel Switched power supply converter with a piezoelectric transformer
US20110277968A1 (en) * 2010-05-14 2011-11-17 Foxconn Technology Co., Ltd. Airflow generator and heat dissipation device incorporating the same

Also Published As

Publication number Publication date
JPS5037367B1 (en, 2012) 1975-12-02

Similar Documents

Publication Publication Date Title
US3681626A (en) Oscillatory circuit for ultrasonic cleaning apparatus
US3432691A (en) Oscillatory circuit for electro-acoustic converter
US2975354A (en) Electrical conversion apparatus
US3708701A (en) Apparatus for driving piezoelectric transformers
JPS58215173A (ja) テレビジヨン表示装置用圧電アルタ電圧発生装置
US3598909A (en) A high-voltage generator circuit configuration utilizing a ceramic transformer
US3694713A (en) Ultrasonic generators
US4583529A (en) High efficiency high frequency power oscillator
US2846581A (en) Transistor pulse generator circuit
US3683210A (en) High voltage generating apparatus utilizing piezoelectric transformers
US3210601A (en) Scanning circuit using controlled rectifiers
US3679918A (en) Self-exciting type high voltage generating apparatus utilizing piezolectric voltage transforming elements
US3778648A (en) Piezoelectric transformers
US2890403A (en) Transistor pulse generator
US3209231A (en) Alternating-current source
US3070758A (en) Transistor oscillator
JP2002017090A (ja) 圧電トランスの駆動方法および駆動装置
US3119972A (en) Transistor pulse oscillator with series resonant circuit
US3038128A (en) Transistor blocking oscillator using resonant pulse width control
US3629682A (en) Inverter with zener-regulated output frequency and voltage
GB993347A (en) Solid state scanning circuits
US3369195A (en) Stabilization of voltage-regulated electronic converters
US3349279A (en) Electronic circuit
US3460025A (en) High frequency,high power source solid state inverter
US3155921A (en) Square wave pulse generator having good frequency stability