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EP0135907B1 - Circuit d'excitation d'un oscillateur piézoélectrique dans un dispositif thérapeutique ultrasonique - Google Patents

Circuit d'excitation d'un oscillateur piézoélectrique dans un dispositif thérapeutique ultrasonique Download PDF

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Publication number
EP0135907B1
EP0135907B1 EP84111125A EP84111125A EP0135907B1 EP 0135907 B1 EP0135907 B1 EP 0135907B1 EP 84111125 A EP84111125 A EP 84111125A EP 84111125 A EP84111125 A EP 84111125A EP 0135907 B1 EP0135907 B1 EP 0135907B1
Authority
EP
European Patent Office
Prior art keywords
oscillator
voltage source
terminal
vibrator
voltage
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
Application number
EP84111125A
Other languages
German (de)
English (en)
Other versions
EP0135907A3 (fr
EP0135907A2 (fr
Inventor
Ralph Meissner
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Priority to AT84111125T priority Critical patent/ATE31257T1/de
Publication of EP0135907A2 publication Critical patent/EP0135907A2/fr
Publication of EP0135907A3 publication Critical patent/EP0135907A3/xx
Application granted granted Critical
Publication of EP0135907B1 publication Critical patent/EP0135907B1/fr
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/0207—Driving circuits
    • B06B1/0223—Driving circuits for generating signals continuous in time
    • B06B1/0238—Driving circuits for generating signals continuous in time of a single frequency, e.g. a sine-wave
    • B06B1/0246—Driving circuits for generating signals continuous in time of a single frequency, e.g. a sine-wave with a feedback signal
    • B06B1/0253—Driving circuits for generating signals continuous in time of a single frequency, e.g. a sine-wave with a feedback signal taken directly from the generator circuit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/50—Application to a particular transducer type
    • B06B2201/55—Piezoelectric transducer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/70—Specific application
    • B06B2201/76—Medical, dental

Definitions

  • the invention relates to a circuit arrangement for supplying the piezoelectric oscillator in an ultrasound therapy head according to the preamble of claim 1.
  • the ultrasound therapy head was connected via a power amplifier to an oscillator which oscillates at a fixed frequency.
  • One was therefore forced either to keep the resonance frequency in a very narrow tolerance band when manufacturing the therapy heads or to readjust the oscillator when the therapy head was changed.
  • the invention has for its object to improve a circuit arrangement of the type mentioned with a simple structure so that a much higher efficiency is achieved; this should be retained without readjusting the frequency of the oscillator even when the therapy head is changed, provided the resonance frequency of the therapy heads is within a practically acceptable tolerance range.
  • the inventive solution to this problem is characterized in claim 1. It is characterized by extremely low circuit complexity and an unusually high level of efficiency. In conjunction with a very low-resistance therapy head according to DE-U-82 20 944, an efficiency of about 60% could be achieved at the high resonance frequency of 880 kHz.
  • the therapy head is part of the oscillator, which cannot oscillate without the therapy head.
  • the resonance frequency of the series resonance circuit is approximately matched to the middle of the tolerance band for the resonance frequency of the therapy head that can be used: As long as the resonance frequency of a therapy head is between 870 and 880 kHz, no adjustment of the resonance frequency of the series resonance circuit is necessary. Nevertheless, the oscillator vibrates at the resonance frequency of the therapy head.
  • an oscillator circuit for an ultrasonic atomizer with a bipolar transistor which also works with a feedback transformer and a series resonant circuit in the control circuit of the transistor.
  • the low resistance of the series resonance circuit at the resonance frequency means that the transistor works continuously in saturation, which makes it slow and it is not possible to achieve an operating frequency that is significantly above 100 kHz.
  • the arrangement according to the invention of the series resonance circuit in the control circuit of a power PA field effect transistor does just the opposite: the series resonance circuit, which has a low impedance at resonance frequency, enables the capacitance of the control path of the field effect transistor to be discharged extremely quickly, so that the circuit arrangement according to the invention can oscillate at a frequency that is practically of the order of magnitude lies above the frequency for which power field effect transistors have been used up to now.
  • devices which protect the field effect transistor from overvoltages, such as can occur when the ultrasound therapy head is not under load: in addition to a low-pass filter parallel to the drain source line, a protective device can be provided which is controlled by the voltage at the drain source line and switches off the oscillator when the voltage mentioned reaches a critical value.
  • 1 designates the piezoceramic vibrator of an ultrasound therapy head, the structure of which is described in detail in DE-U-82 20 944 and which has a real resistance of ⁇ 20 ohms at the series resonance point.
  • the parallel circuit comprising this oscillator 1, an RF choke 2 and a resistor 3 is connected between the first terminal P of a DC voltage source (not shown) and the drain electrode D of a power field-effect transistor, which is connected via a low-pass filter with a resistor 13 and a capacitor 14 on the other hand, is connected to the second terminal N of the DC voltage source.
  • the primary winding 22 of a feedback transformer 20 Between this second terminal N and the source electrode S is the primary winding 22 of a feedback transformer 20, the secondary winding 21 of which forms a series resonance circuit with a fixed capacitor 24 and an adjustable capacitor 23, which is connected in parallel with a resistor 7; the latter forms with a further resistor 5 a voltage divider connected between the terminals P and N, the tap of which is connected via a series resistor 11 to the gate electrode G of the field effect transistor 10 and is dimensioned such that the oscillator oscillates when a direct voltage is applied.
  • a capacitor 6 is also located between P and N.
  • the series resonance circuit is tuned with the aid of the capacitor 23 approximately to the middle of the tolerance band in which the resonance frequencies of the therapy heads in question must lie.
  • the feedback condition remains fulfilled within this tolerance band and the oscillator oscillates to the series resonance of the connected therapy head.
  • the power that can be output by the therapy head can be adjusted by changing the voltage of the DC voltage source and is, for example, at

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Apparatuses For Generation Of Mechanical Vibrations (AREA)
  • Percussion Or Vibration Massage (AREA)

Claims (4)

1. Montage pour alimenter le cristal piézoélec- trique, situé dans une tête d'ultrasonothérapie, constitué par une source de tension continue comportant des première et seconde bornes, et comportant un oscillateur servant à produire une tension alternative d'alimentation et dont la fréquence est égale approximativement à la fréquence de résonance du cristal et est supérieure à 500 kHz, caractérisé par le fait
que l'oscillateur est un oscillateur à simple alternance comportant un transducteur à effet de champ de puissance (10) possédant une électrode de grille (G), une électrode de grain (D) et une électrode de source (S),
que l'électrode de drain (D) est raccordée par l'intermédiaire du cristal (1) à la première borne (P) de la source de tension continue et que l'électrode de source (S) est raccordée par l'intermédiaire de l'enroulement primaire (22) d'un transformateur de réaction (20) à la seconde borne (N) de la source de tension continue,
que l'électrode de grille (G) est raccordée par l'intermédiaire d'une résistance additionnelle (11 ) d'un diviseur de tension (5, 7), qui est branché entre les bornes de la source de tension continue, et
qu'en parallèle avec la résistance (7) du diviseur de tension, qui est relié à la seconde borne (N) de la source de tension continue, se trouve branché un circuit résonant série possédant un condensateur (23, 24) et l'enroulement secondaire (21 ) du transformateur de réaction (20) et dont la fréquence de résonance est égale approximativement à la fréquence de résonance de l'oscillateur (1).
2. Montage suivant la revendication 1, caractérisé par le fait que la résistance de la tête d'ultraso- nothérapie est, à l'état chargé, inférieure à 100 ohms et de préférence < 20 ohms.
3. Montage suivant la revendication 1 ou 2, caractérisé par le fait qu'un filtre passe-bas (13, 14) est monté entre l'électrode de drain et l'électrode de source.
4. Montage suivant la revendication 3, caractérisé par un dispositif de projection, qui est commandé par la tension présente entre les électrodes de drain et de source et débranche l'oscillateur lorsque cette tension atteint une valeur limite critique.
EP84111125A 1983-09-28 1984-09-18 Circuit d'excitation d'un oscillateur piézoélectrique dans un dispositif thérapeutique ultrasonique Expired EP0135907B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84111125T ATE31257T1 (de) 1983-09-28 1984-09-18 Schaltung zur anregung eines ultraschalltherapiekopfes.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833335158 DE3335158A1 (de) 1983-09-28 1983-09-28 Schaltung zur anregung eines ultraschall-therapiekopfes
DE3335158 1983-09-28

Publications (3)

Publication Number Publication Date
EP0135907A2 EP0135907A2 (fr) 1985-04-03
EP0135907A3 EP0135907A3 (fr) 1985-06-05
EP0135907B1 true EP0135907B1 (fr) 1987-12-09

Family

ID=6210318

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84111125A Expired EP0135907B1 (fr) 1983-09-28 1984-09-18 Circuit d'excitation d'un oscillateur piézoélectrique dans un dispositif thérapeutique ultrasonique

Country Status (3)

Country Link
EP (1) EP0135907B1 (fr)
AT (1) ATE31257T1 (fr)
DE (2) DE3335158A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5001649A (en) * 1987-04-06 1991-03-19 Alcon Laboratories, Inc. Linear power control for ultrasonic probe with tuned reactance
DE3934921C1 (en) * 1989-10-20 1991-04-25 Kln Ultraschall Gmbh, 6148 Heppenheim, De Switching circuitry for reactive loads such as coils, and oscillators - has diode in antiparallel with each diode in series with semiconductor switch
JP4889832B2 (ja) * 2010-04-09 2012-03-07 オリンパスメディカルシステムズ株式会社 超音波手術システム及び外科用処置具
CN117102008A (zh) * 2023-08-07 2023-11-24 江苏大学 半控型步进扫频的变扫模式超声激励信号发生装置及方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3584244A (en) * 1969-06-10 1971-06-08 Clevite Corp Oscillator circuit for an ultrasonic cleaner, utilizing a saturable core transformer
US4012647A (en) * 1974-01-31 1977-03-15 Ultrasonic Systems, Inc. Ultrasonic motors and converters
US4311922A (en) * 1979-11-14 1982-01-19 General Electric Company Variable excitation circuit

Also Published As

Publication number Publication date
EP0135907A3 (fr) 1985-06-05
EP0135907A2 (fr) 1985-04-03
ATE31257T1 (de) 1987-12-15
DE3467981D1 (en) 1988-01-21
DE3335158A1 (de) 1985-04-04

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