Abstract: A circuit including a transformer, preferably a laminated piezoelectric transducer, in combination with a positive feedback amplifier circuit, capable of serving: 1) to produce either an audible or ultrasonic signal; or 2) as an energy source capable of driving an auxiliary high voltage device with an initial and continuing low voltage source such as a battery.

Abstract: In a piezoelectric transformer control circuit for driving a load (2) connected to a piezoelectric transformer (1), an oscillation signal as a basis of driving of the piezoelectric transformer (1) is oscillated, and the piezoelectric transformer (1) is driven by a driving circuit (4) on the basis of the oscillation signal. A pulse power supply circuit (5) for supplying a pulse voltage to the driving circuit (4) intermittently drives the driving circuit (4) by pulse-modulating the pulse voltage to be supplied to the driving circuit (4).

Abstract: A crystal oscillator in which IC control terminal electrodes for writing temperature compensation data in an IC chip are formed on side surfaces of a main body while being distanced from the top and bottom surfaces of the main body. The IC control terminal electrodes will not be short-circuited with a conductive pattern for sealing the crystal oscillating element on the top surface, and the IC chip will not be destroyed by a welding current which flows when a metal cover is mounted on the top surface. The IC control terminal electrodes will not be short-circuited with other wiring conductors during the soldering to bond the crystal oscillator to a printed circuit board. The compensation data or other data written in the IC chip can be stably maintained, thereby securing a stable operation.

Abstract: A piezoelectric transformer inverter can suppress ripples generated by the oscillations of a transformer, and can reduce the possibility of occurrence of beats in the inverter. In this piezoelectric transformer inverter, a switching element is disposed at a stage before an inverter circuit driving a discharge tube, and the switching element is switched on and off by switching signals from a chopper-duty control unit. Then, an input voltage is converted into a rectangular-wave voltage having a chopper circuit frequency to be supplied to the inverter circuit, and a frequency of n times a driving frequency of the inverter circuit and a chopper frequency of the chopper circuit are set in such a manner that these two frequencies are not close to each other.

Abstract: A drive circuit performing time division drive of a piezoelectric transformer realizes a wide dimmer control range and prevention of blinking at a frequency visually perceptible upon lacking of output, prevention of blinking of a load at the frequency visually perceptible before initiation of turning ON of the load, and suppression of heating of parts of the drive circuit at no load operation. Time division frequency signals used in time division driving are generated in a plurality of kinds in a dimmer control circuit. The generated plurality of kinds of time division frequency signals is selected depending upon the condition of the load and a dimmer condition of the piezoelectric transformer and thus to select optimal time division drive frequency or simultaneously with a plurality of time division drive frequency, the piezoelectric transformer is driven.

Abstract: An instrumented sports apparatus includes a closely spaced array of discrete sensor elements coupled to a contact surface thereof for converting a contact force between the contact surface and an object into a plurality of discrete output signals. The signals are processed and information based thereon generated, which is representative of one or more parameters of interest. In an exemplary embodiment, as instrumented golf club displays information such as club head speed, club head angle, and club head elevation upon impact with a golf ball, permitting the golfer to adjust his swing on the next stroke. Since the instrumentation and display are entirely self-contained in the club, a golfer is not constrained in the use of the club and may enjoy the benefits thereof during play on a golf course.

Abstract: A method for manufacturing a cofired multi-layer piezoelectric transformer device includes forming first and second green shapes of a sinterable ceramic composition and applying metallization layer therebetween. Upon cofiring, the composite structure comprises first and second electroactive members bonded together by a conductive layer therebetween. External electrodes are applied and the electroactive members are polarized in a thickness direction, between their two major faces. The first and second electroactive members are arranged such that deformation of one electroactive member results in corresponding deformation of the other electroactive member. The device provides substantial transformation ratios in which relatively high power may be transferred in relation to the size of the unit, operability over wide input and output frequency bandwidths, and electrical isolation of the input voltage and current from the output voltage and current.

Abstract: A piezoelectric inverter is disclosed. In the piezoelectric inverter, an input voltage controller, having a switching transistor and a current circulatingelement, converts an input voltage into a rectangular pulse alternating-current voltage. A piezoelectric transformer driver, having an inductive element, outputs an alternating-current voltage having a substantially constant frequency lower than the frequency of the alternating-current voltage output from the input voltage controller. A load current detect or detects a load current flowing through a discharge tube connected to a piezoelectric transformer. A duty factor controller controls the duty factor of the rectangular pulse of the input voltage controller in response to the output of the load current detector so that the load current coincides with a substantially constant target current value. The piezoelectric inverter thus controls the mean voltage of the alternating-current voltage applied to the piezoelectric transformer.

Abstract: This invention relates to an optimization method for driving a piezoelectric actuator by dynamic detection of its electromechanical characteristics, as well as to a device, in particular a phacoemulsifier based thereupon. The piezoelectric actuator includes a voltage driven, two-terminal piezoelectric transducer. The method for detection of its electromechanical characteristics is such that the drive of the transducer is cyclically discontinued in order to detect the characteristic parameters of its free motion by detection of the parameters of the signal generated by the transducer at the ends of the two terminals.

Abstract: Disclosed is a power supply circuit for boosting drive voltage by a booster circuit, inputting the boosted voltage to the primary side of a piezoelectric transformer, and driving a load with an impedance of large temperature dependency by output voltage generated at the secondary side of the piezoelectric transformer. The circuit has: an excessively-small current detection means that outputs excessively-small current signal when load current flowing through the load is smaller than a predetermined value; a stopping means that stops the operation of the booster circuit when the excessively-small current signal is output; and a delaying means that sets a delay time according to the level of the output voltage. The stopping means determines the execution or inexecution of the operation according to the existence of the excessively-small current signal when the delay time passes.

Abstract: A method for high resolution trimming of PCB components, such as capacitors, inductors, transmission lines, transformers, antennas, resistors, etc. The method includes drilling or milling the PCB to effect the electrical characteristics of the component. The actual component can be machined to reduce the size of the component, or electrical connections to the component can be severed. The method can be used to set the capacitance of a tuning capacitor for an oscillator circuit. The tuning capacitor is etched out of the conductive planes on opposing sides of the PCB. The dielectric substrate of the PCB acts as the dielectric for the capacitor. The conductive planes are also etched to define conductive traces and connection pads suitable for surface mounting and electrically connecting the various electrical components on the PCB. The area of the selectively etched capacitive plates has a capacitance that is predetermined.

Abstract: A circuit for driving a piezoelectric transformer, which is suitable for driving a piezoelectric transformer having a load such as a cold cathode fluorescent tube, and capable of coping with a wide range of a power source voltage and operating with high efficiency. The driving circuit includes a series circuit constituted by an equivalent input capacitance of the piezoelectric transformer and an inductance circuit and provided between power source terminals, and a switching transistor having both terminals of a main current path thereof in parallel connected to a part of the series circuit including the equivalent input capacitance. The inductance circuit includes a first inductance element of boosting constitution such as an auto-transformer and a second inductance element of non-boosting constitution such as a coil. The first and second inductance elements are selectable alternately.

Abstract: A power source 1 and an operating circuit 4 incorporating a waveform generating circuit 5 for synthesizing composite wave W obtained by synthesizing a sine wave of primary oscillations and a sine wave of secondary oscillations of a Rosen-type piezoelectric transformer and an amplifying circuit 6 raises the voltage of the composite wave so that composite wave W' (having a waveform similar to that of W) is, as input voltage V.sub.in, supplied to the Rosen-type piezoelectric transformer PT. Thus, output voltage V.sub.out having greater output electric power and higher transmitting efficiencies as compared with output voltage which can be obtained from a conventional structure in which input voltage in a single oscillation mode is employed can be produced to load resistor R.sub.o.

Abstract: A piezoelectric signal converter comprises a piezoelectric ceramic, four electrodes P.sub.A, P.sub.B, Q.sub.C and Q.sub.D, a load resistance R consisting of N parts R.sub.i (i=1, 2, . . . , N), N-1 terminals T.sub.i {i=1, 2, . . . , (N-1)} between two parts R.sub.i and R.sub.(i+1), and two terminals T.sub.0 and T.sub.N, formed on the electrodes Q.sub.C and Q.sub.D, respectively. The electrodes P.sub.A, P.sub.B, Q.sub.C and Q.sub.D are formed on four side surfaces A, B, C and D, of the piezoelectric ceramic, respectively. The load resistance R is connected between the terminals T.sub.0 and T.sub.N. The piezoelectric ceramic, the electrodes P.sub.A, P.sub.B, Q.sub.C and Q.sub.D, form a piezoelectric vibrator. When a high-frequency electric signal E.sub.IN with a voltage V.sub.IN is applied to the electrodes P.sub.A and P.sub.B, the piezoelectric vibrator is vibrated at a frequency approximately equal to the resonance frequency of the piezoelectric ceramic.

Abstract: Circuits for use in ignition systems are disclosed which use a resonating piezoelectric transformer along with complementary circuit components, to efficiently convert a DC first voltage to a transformer-output AC second voltage. In the preferred embodiment of the invention, a High Displacement Piezoelectric (HDP) transformer converts a DC voltage into an AC voltage which is rectified into a DC signal of sufficiently high voltage to create a spark across the spark gap of a spark plug. The transformer circuit may be a "self resonating" circuit which relies on an initial pulse from turning on the DC power supply to cause the transformer to begin resonating. In a modified circuit the circuit is not "self resonating" and instead has a phase shift oscillator sub-circuit that provides small pulse signals to start the transformer resonating when the circuit is initially turned on.

Abstract: A motion detector for detecting movement of a rail based vehicle and the direction of that movement is provided. The motion detector can be integral with or attachable to an end-of-train unit and can include a single axis accelerometer mounted at an angle from the rails for detecting acceleration in both the lateral and vertical directions. A systems controller, which can include an analyzer, can be provided to receive and analyze output from the accelerometer to determine a motion state and a direction. A power controller can be provided for supplying power to the accelerometer on an intermittent basis to conserve power. A calibration unit can be provided to both initially calibrate and to subsequently recalibrate the accelerometer after a stopped motion state is detected. Additionally, an input/output port and an output driver for conditioning the signal for output to the end-of-train unit can be provided.

Abstract: A driving circuit of the present invention includes first and second piezoelectric transformers 12, 14 for outputting a voltage at a secondary terminal which is input from a primary terminal utilizing a piezoelectric effect, frequency control means 21 for outputting a frequency signal for operating the first piezoelectric transformer 12 at a required frequency voltage, phase reversing means 16 for reversing a phase of the frequency signal by 180 degrees, driving circuits 13, 15 for applying a frequency voltage to each of the piezoelectric transformers 12, 14 based on these frequency signals of which phases are different from each other by 180 degrees, a discharge tube 11 in which an output of the first piezoelectric transformer 12 is applied to a first input terminal and an output of the second piezoelectric transformer 14 is applied to a second input terminal, a circuit 20 for controlling a voltage of the first piezoelectric transformer 12 so that a current flowing in this discharge tube becomes to be consta

Abstract: A piezoelectric transformer driving circuit and method can prevent degradation of characteristics of a piezoelectric transformer. A repetition frequency of a drive voltage lower than a predetermined value, sweeping range narrower than a predetermined range and an output voltage of the piezoelectric transformer higher than a predetermined reference value are detected by a load current comparing circuit and an output voltage comparing circuit. In response to the results of the comparisons, a sweeping range varying means varies the repetition frequency to be higher than an upper limit value of the sweeping range in a frequency sweeping oscillator. By variation, the sweeping of the output voltage of the piezoelectric transformer is initiated from a small value to correct an effective value of a piezoelectric transformer vibration velocity to prevent degradation of characteristics of the piezoelectric transformer.

Abstract: A transponder device, receiving a plurality of waves having differing frequencies, and producing a wave, having a frequency differing from the plurality of received waves, having characteristic modifications, having a mixer, receiving at least two waves and producing a mixed wave having a frequency differing from the received plurality of waves; and a wave modifying device, producing a characteristically modified wave from an input wave, the mixer being interconnected with the wave modifying device to produce, from the received plurality of waves, an output which is both characteristically modified and at a frequency of the mixed wave. The device may include one or more antenna structures, and preferably produces a mixed wave which is then characteristically modified and emitted from the device. The wave modifying device is, for example, a semiconductor modulator or an acoustic wave device.

Abstract: A circuit including a transformer, preferably a laminated piezoelectric transducer, in combination with a positive feedback amplifier circuit, capable of serving: 1) to produce either an audible or ultrasonic signal; or 2) as an energy source capable of driving an auxiliary high voltage device with an initial and continuing low voltage source such as a battery.

Abstract: A piezoelectric transformer-inverter in which a fluorescent light tube is light-modulated when a frequency controller changes the frequency of a drive voltage applied from a piezoelectric transformer drive circuit to a piezoelectric transformer in correspondence with a light-modulating voltage to thereby change the boost ratio of the piezoelectric transformer. A PWM inverter output variable circuit adjusts an average voltage supplied from a PWM inverter to a piezoelectric transformer drive circuit. When tube current is low, the average voltage is low, and when the tube current is high, the average voltage rises. Consequently, fluctuation in the drive frequency of the piezoelectric transformer is restricted even when the light-modulating voltage changes, making it possible to drive the piezoelectric transformer with a good boost ratio.

Abstract: A system includes a first transducer and a second transducer coupled together through a coupling medium communicating undulating pressure wave from the first transducer to the second transducer for the transfer of electrical power from an external controller energizing the first transducer transducing the power signal into an undulating pressure wave communicated through the medium to the second transducer traducing the undulating pressure wave into an electrical response signal that can be converted into useful power for powering an embedded sensory and actuation control unit. The primary advantage of the system is the transfer of power through a coupling medium without the use of electrical power wires.

Abstract: The application of a piezoceramic resonator (PR), connected in parallel to a discharge lamp and in series to cathode filaments of a lamp, provides reliable means of preheating of cathode filaments facilitating a soft start of a fluorescent lamp. The piezoceramic resonator is a polarized piezoceramic element formed in a form of rectangular plate, disk, cylinder, etc. The linear size and shape of the PR determine the type of oscillation, electromechanical resonant frequency and frequency characteristics. The PRs with radial, contour or longitudinal oscillations are best suited for application to a piezoelectronic ballast. Piezoceramic resonators and filters as frequency-selective elements in measuring and radio communication instruments are widely used in weak alternating electrical fields, where the intensity of field does not exceed an order of volts per mm.

Abstract: In a steady-state operation, a rectified voltage obtained from an output current Io of a piezoelectric transformer 1 is compared in a comparator 10 with Vref. When the voltage is lower than Vref, a signal Vdown is at an "H" level, and otherwise it is at an "L" level. A switch SW1 or SW2 is thus turned on to charge or discharge a capacitor Cvco. This has an effect of sweeping the oscillation frequency of a VCO 14 downward or upward to increase or reduce the output voltage Vo of the piezoelectric transformer 1 which is driven at the oscillation frequency. When a load 2 is open-circuited, a voltage VR obtained from an output voltage Vo becomes higher than Vmax to set a flip-flop 13 and turn on a switch SW3. The capacitor voltage Vvco is thus reduced to reduce the oscillation frequency of the VCO 14 and reduce the output voltage Vo. When the voltage VR becomes lower than Vmin, the flip-flop 18 is reset by the output of the comparator 16 to turn off the switch SW3.

Abstract: A pulse frequency modulation drive circuit (1114) for a piezoelectric transformer (1102) is provided. Circuit (1114) includes a piezoelectric transformer (1102) having a resonant frequency and an input and an output section. A frequency feedback network connected to the piezoelectric transformer (1102) and an output level sense (1112) connected to the piezoelectric transformer (1102) is also provided. A drive circuit (1114) has a first switch (S.sub.1) and a third switch (S.sub.3) having a capacitance (1118) therebetween. A second switch (S.sub.2) and a fourth switch (S.sub.4) connect a supply voltage (V.sub.IN) to each of a pair of inductors (L.sub.1 and L.sub.2) and the second switch (S.sub.2) and the fourth switch (S.sub.4) are driven 180.degree. out of phase at the resonant frequency of the piezoelectric transformer (1102).

Abstract: A boosting drive circuit includes first and second series combinations of a coil and a transistor. The two series combination of a coil and a transistor are connected in parallel. The middle points between the coils and the transistors are connected to respective primary electrodes of a piezoelectric transformer. The transistors are alternately operated with a two-phase drive circuit. Thus, a boosting drive circuit providing for the class "semi-E" operation is formed. A driving voltage control circuit controls an average voltage applied to the input terminal of the boosting drive circuit to ensure that current on the secondary electrode side of the piezoelectric transformer is controlled at a predetermined value is provided between the input power supply and the boosting drive circuit.

Abstract: The present invention provides a driving circuit for a piezoelectric transformer. The driving circuit comprises a driver circuit and a detector circuit. The driver circuit is electrically connected to a primary side of the piezoelectric transformer for generating a driving signal which is transmitted to the primary side of the piezoelectric transformer so that the piezoelectric transformer exhibits a vibration due to piezoelectric effect and generates a transformed output voltage on a secondary side thereof. The detector circuit is electrically connected to an output side of the driver circuit for receipt of the driving signal from the driver circuit and also electrically connected to the secondary side of the piezoelectric transformer for receipt of the transformed output voltage from the piezoelectric transformer so that the detector circuit is capable of detecting a drop of the transformed output voltage when a voltage level of the driving signal is in an available range.

Abstract: A motion detector for detecting movement of a rail based vehicle and the direction of that movement is provided. The motion detector can be integral with or attachable to an end-of-train unit and can include a single axis accelerometer mounted at an angle from the rails for detecting acceleration in both the lateral and vertical directions. A systems controller, which can include an analyzer, can be provided to receive and analyze output from the accelerometer to determine a motion state and a direction. A power controller can be provided for supplying power to the accelerometer on an intermittent basis to conserve power. A calibration unit can be provided to both initially calibrate and to subsequently recalibrate the accelerometer after a stopped motion state is detected. Additionally, an input/output port and an output driver for conditioning the signal for output to the end-of-train unit can be provided.

Abstract: An electronic apparatus that performs switching with the use of a piezoelectric element comprises a piezoelectric element 11, a first monitor electrode 15, and a second monitor electrode 16, the latter two being provided thereon and intended to output electric shock signals that are generated when a shock has been applied to the piezoelectric element 11 to thereby distort it. Whereby, a shock is applied to the electronic apparatus that contains the piezoelectric element 11 and a shock is applied to the built-in piezoelectric element 11. This makes it possible to output for the purpose of controlling the operation of the respective functions an electronic shock signal that is generated when the piezoelectric element 11 is distorted. As a result, it is possible to reduce the number of switch parts for, and hence the size of, the electronic apparatus and reduce the amount of time and labor for performing the switching operation by utilizing the piezoelectric effect of the piezoelectric element.

Abstract: A digital temperature compensation oscillator by which its AFC operation to a receive signal cannot be disturbed by temperature compensation operation. A digital temperature compensation oscillator comprises a temperature sensor, an address creating section, a ROM, latching means, and a voltage-controlled crystal oscillator. The temperature sensor produces an output signal varied according to ambient temperatures. The address creating section converts an output from the temperature sensor into a signal and then creating it as a ROM (read-only memory) address. The ROM stores a control voltage to compensate a frequency variation due to ambient temperatures of a voltage-controlled crystal oscillator. The latching means holds or passes data output from the ROM according to an external control signal. The D/A converter produces a control voltage for the voltage-controlled crystal oscillator according to the latching means.

Abstract: A piezoelectric resonator (10) includes a single crystal elongated plate (12) having a transverse extensional mode of oscillation. Two sets of split electrodes (20,22,30,32) are provided on the surfaces (14,16) of the plate (12) to define two acoustically coupled oscillating regions (24,26) therebetween. The oscillating regions (24,26) present a similar inductance and have similar performance to allow the use of the resonator (10) in a double-ended electrical transformer circuit (100). An AC source (112) drives non-opposing top and bottom electrodes of the resonator (110). The remaining electrodes are coupled with shunt capacitors to provide two resonant LC circuits with the resonator (110) so as to provide a voltage gain for driving a load.

Abstract: A system and method for tuning and controlling ultrasonic handpieces by incorporating a broad-spectrum signal as at least a component of the signal used to drive the handpiece. The response of the handpiece to this broad-spectrum signal is measured and the frequency or amplitude or both of the drive signal are adjusted in order to maintain the desired level of handpiece performance. The operation of the systems and the performance of the methods described enables the handpiece to be operated in a most effective manner over a more widely varying range of mechanical load and thermal conditions than was possible through the use of prior control systems and methods.

Abstract: A resonant circuit of the present invention has a ceramic substrate, a quartz element provided on said substrate, and a capacitor for temperature compensation. Connection terminals are formed on the rear of the substrate in order to mount the resonant circuit to another substrate. A seam ring for air-tight sealing is positioned at the edges of the substrate. The quartz oscillator with this configuration can be mounted without resorting to leads.

Abstract: Piezoelectric resonator structures and circuits therefor are provided to p the energy available for vibrational deformation in a resonator, between the driving electrodes of the resonator structure. Field trapping electrodes are disposed to enclosed the driving electrodes in the resonator structures which are arranged in circuits to derive electric fields between the field trapping electrodes in an opposite direction to that of an electric field between the driving electrodes.

Abstract: A combination of two control methods are used, one of which is a method to control the boosting ratio of the piezoelectric transformer and another is a method to control the driving waveform of the piezoelectric transformer. The threshold values for switching the control methods are set with a hysteresis characteristic in order to avoid instability in the driving frequency at the time of switching and also to avoid driving at a natural frequency. When the source voltage is fixed, the driving frequency is increased by changing the resistance of the detection resistor 16 until the driving frequency reaches the natural frequency causing problems. When the driving frequency reaches the natural frequency, the power supply to the driving circuit is reduced to reduce the amplitude of the driving wave for reducing the driving frequency without changing the output voltage. At this state when the amplitude is small, the minimum output voltage is obtained by increasing the driving frequency to the natural frequency.

Abstract: A vibrating gyroscope includes a ring-shaped vibrator having a node. A driver element is provided to cause the vibrator to vibrate flexurally. A detector element is formed along an axis of the vibrator and has a surface disposed such that the surface is non-perpendicular to a direction of vibration of said vibrator while the vibrator remains stationary. In one embodiment, the vibrator is metallic and the driver and detector are piezoelectric elements. In another embodiment, the vibrator is piezoelectric and the driver and detector are metal electrodes.

Abstract: A control circuit for a piezoelectric buzzer, notably for automobiles, comprises a circuit for generating alternately two different frequencies and features two input supply terminals (1, 2) and two output terminals (4, 5) for buzzer activation. The control circuit includes a first flip-flop with a first and a second output, of which one carries positive and the other negative voltage. Also provided is a second flip-flop with a first input and an output, the first input connecting to the first and second outputs of the first flip-flop, each via a resistor (R4, R3). The second flip-flop consists of a parallel wiring of a first series connection of a capacitor (C2) and an inverter with Schmitt trigger input (IC1C), and a second series connection of a resistor (R5) and an inverter with Schmitt trigger input (IC1D), while a resistor is wired in parallel with the second series connection.

Abstract: In a piezoelectric transformer driving circuit which comprises a boosting circuit (2) for boosting an input direct current voltage, a piezoelectric transformer (3), a current voltage converting circuit for converting a load alternating current which flows in the load (9), and a rectifier circuit (5), an input voltage detecting and comparing circuit (10) compares the input direct current voltage with a minimum voltage which is determined by a setting value of the load alternating current to produce a first voltage having a high level when the input direct current voltage is lower than the minimum voltage and to produce a second voltage having a low level when the input direct current voltage is higher than the minimum voltage. A reference voltage producing circuit (6a) produces one of first and second reference voltages in response to one of the first and second voltages.

Abstract: In a driver of a CCFL for lightening the CCFL by using a piezoelectric transformer, a current supplied from a power source or a power consumption of the CCFL is detected and the piezoelectric transformer is on-off driven at a frequency different from an operating frequency of the piezoelectric trabsformer by a pulse width modulation signal having a duty cycle ratio corresponding to the detected value. The current supplied from the power source does not exceed a predetermined value, so that a capacity of the power source can be small and thus the cost of the power source can be reduced.

Abstract: A circuit (10) for driving a piezoelectric transformer (12) in a phase locked mode without using an external reference signal. The circuit (10) utilizes a 555 timer circuit operated in a stable mode which is responsive to a feedback phase signal (18) coupled from an output signal (20) of the piezoelectric transformer (12). The feedback phase signal (18) overpowers the trigger circuit of the timer to phase lock the timer to an output of the piezoelectric transformer (12) at a resonant frequency of the piezoelectric transformer (12). The circuit (10) provides a simplified phase lock circuit without the need for a typical PLL configuration.

Abstract: An actuating circuit of a piezoelectric transformer which is small in thickness and size and has a wide input voltage range is developed. In the actuating circuit of the piezoelectric transformer, when a sine wave outputted from a AGC circuit is input to a delta-sigma modulator, the sine wave switches output driver and switches a second output driver through an invertor with a 1-bit quantized bit signal so as to generate a pulse signal having an amplitude of power supply voltage Vdd from the GND potential. Actuating waves output from the output drivers and are applied to 1 piezoelectric transformer extracting resonance frequency of a piezoelectric transformer through a filtering effect provided with an input capacitance of the piezoelectric transformer and coil converting the 1-bit quantized bit signal into a sine wave. Consequently, since the piezoelectric transformer can be operated with the sine wave, the piezoelectric transformer can be actuated efficiently.

Abstract: A piezoelectric transformer driving circuit includes a boosting circuit receiving an input DC voltage to generate an AC voltage for driving a piezoelectric transformer, a frequency control circuit for controlling the frequency of the AC voltage applied to the piezoelectric transformer to control a step-up ratio of the piezoelectric transformer, and a drive voltage control circuit for controlling the voltage of the AC voltage applied to the piezoelectric transformer at a predetermined level, regardless of variation of the input DC voltage.

Abstract: A method for determining the voltage current phase relationship of a piezoelectric phacoemulsification handpiece includes the steps of obtaining an AC voltage signal corresponding to the operating AC voltage of a piezoelectric handpiece and obtaining an AC current signal corresponding to the operating AC current of the piezoelectric handpiece. From said AC current signal, onset of a current cycle is determined and after onset of the current cycle, a voltage (V.sub.I) corresponding to a time necessary for the AC current signal to reach a maximum value is produced. Also, after onset of the current cycles, a voltage (V.sub.v) corresponding to a time necessary for the AC voltage signal to reach a maximum value is produced. Using an A/D converter, a digital output (D.sub.v) corresponding to (V.sub.v) is produced and a digital output (D.sub.I) corresponding to (V.sub.I) is produced. Comparing (D.sub.v) and (D.sub.

Abstract: A system and method for tuning and controlling ultrasonic handpieces by incorporating a broad-spectrum signal as at least a component of the signal used to drive the handpiece. The response of the handpiece to this broad-spectrum signal is measured and the frequency or amplitude or both of the drive signal are adjusted in order to maintain the desired level of handpiece performance. The operation of the systems and the performance of the methods described enables the handpiece to be operated in a most effective manner over a more widely varying range of mechanical load and thermal conditions than was possible through the use of prior control systems and methods.

Abstract: An inverter power source apparatus using a piezoelectric transformer, has: variable oscillating device for oscillating a pulse signal; pulse-width changing device for changing a width of said pulse signal of said variable oscillating device; driving device for generating a driving signal on the basis of an output of said pulse-width changing device; a piezoelectric transformer which is driven by said driving signal, drives a predetermined load, and has input and output electrodes; detecting device for detecting a relationship between said driving signal and a resonance frequency of said piezoelectric transformer, and for, on the basis of a result of the detection, controlling a frequency of said oscillation signal of said variable oscillating device so that a difference between said resonance frequency and a frequency of said driving signal is substantially within a preset range; and pulse-width controlling device for, when a detection results of said detecting device shows that said difference between said r

Abstract: A pressure gauge is used with a receiver device of a tire pressure indicator for indicating the pressure condition in a pneumatic tire, and includes a casing formed with an aperture and adapted to be mounted on the tire such that pressure in the tire enters into the casing via the aperture, and a signal generating device disposed in the casing and capable of transmitting wirelessly a pressure signal to be received by the receiver device when the pressure in the tire is not within a predetermined normal operating pressure range.

Abstract: In a DC--DC converter comprising a piezoelectric transformer (25) having an input capacitance between a pair of transformer input teminals and a transformer resonant frequeney, an input switching stage (27) responsive to a DC input signal for supplying a sinusoidal transformer input signal, and an output rectifier stage (29) for producing a converter output voltage across a load resistor (23), the switching stage includes an input series inductor (39) connected in series to one of the transformer input terminals and having an input series inductance that defines a switching resonant frequency in cooperation with the input capacitance to be different from the transformer resonant frequency. It is preferred when the switching stage is operable in zero volt switching that the input series inductance be either between 1.0 and 2.2 .mu.H or between 3.0 and 3.4 .mu.H, or more preferably either between 1.4 and 1.8 .mu.H or about 3.0 .mu.H, if the input series inductance should be 2.8 .mu.

Abstract: A transformer circuit (10) for a piezoelectric transformer (12) having dual inputs which can piezoelectrically interfere with one another to provide adjustable output gain. The transformer circuit (10) provides two pulse-position-modulated input signals (18, 20) which are substantially identical waveforms, but being phase shifted from one another. When the signals (18, 20) constructively interfere maximum gain is achieved. When the two signals (18, 20) destructively interfere minimum gain is achieved. The waveforms may be of any arbitrary type including square, sine, triangle, sawtooth or irregular. Both input signals (18, 20) are at a resonant frequency of the piezoelectric transformer (12) and have a fifty percent duty cycle so as to always provide highest efficiency within the transformer (12).

Abstract: A cold cathode tube is used for a back light illuminating a liquid crystal with a light from the back. A ceramic transformer is used instead of a conventional wound transformer for a power source to light this cold cathode tube to eliminate various problems caused by transformers. The output voltage and current of this ceramic transformer are coordinated with the cold cathode tube by utilizing the frequency characteristic of the boosting ratio of the ceramic transformer to light the cold cathode tube and adjust the light. The output from an oscillator is amplified and is applied to a ceramic transformer. The output frequency from the oscillator is swept from the higher side to the lower side. When the output frequency decreases from fa.fwdarw.fb, the output voltage of the ceramic transformer in the case that the load resistance indicated by the solid line is large will be Vb and the cold cathode tube will be lighted.

Abstract: The device for determining and/or monitoring a predetermined level of contents in a container comprises a sensor, which is so mounted on the container at the level of contents to be monitored that it comes into contact with the contents of the container when the same reach the predetermined level. The sensor is excited to mechanical vibrations at its natural resonant frequency by an exciting arrangement. An evaluating circuit serves for causing indicating and/or switching operations in a manner dependent on whether the frequency of the mechanical vibrations of the sensor is higher or lower than a switching frequency. Associated with the sensor is an electrical circuit element which has a characteristic parameter, whose value bears an unambiguous relationship to the natural resonant frequency of the sensor. In the evaluating circuit the switching frequency is set in accordance with the value of the characteristic parameter of the electrical circuit element.