413 results about "Piezoelectric transformer" patented technology

A circuitry comprises a converter means for generating an alternating current signal from an energy from an energy source, a piezo transformer with an input and an output, wherein the input of the piezo transformer is electrically coupled to the converter means, to receive the alternating current signal as an excitation on the input side from the converter means, and wherein the output of the piezo transformer is designed to provide an output current, and a load, which is coupled to the output of the piezo transformer, so that output current flows through the same. The load is designed to convert at least part of the electrical energy supplied by the output current flowing through the load into another form of energy. The load is further designed such that a useful power provided in the form of useful energy is substantially proportional to the output current. The circuitry is designed to adjust the output current to a predetermined value. The described circuitry allows the supply of a load with particularly high efficiency, low interference emission and good regulation characteristics.

In general, the invention is directed to an IMD having a piezoelectric transformer to power a lead-based sensor. The IMD powers the piezoelectric transformer with a low amplitude signal. The piezoelectric transformer serves to convert the voltage level of the low amplitude signal to a higher voltage level to drive the sensor produced by a battery in the IMD to voltage levels appropriate for IMD operation. A piezoelectric transformer offers small size and low profile, as well as operational efficiency, and permits the IMD to transmit a low amplitude signal to a remote sensor deployed within an implantable lead. In addition, the piezoelectric transformer provides electrical isolation that reduces electromagnetic interference among different sensors.

A piezoelectric transformer converts a first voltage, supplied from a voltage source, into a second, different, stabilized voltage by a DC / AC converter followed by a rectifier connected in cascade to a filter. The DC / AC converter block includes a driver block followed by the piezoelectric transformer, such that the driver block feeds the piezoelectric transformer with a pulse train (21) the frequency of which coincides with the switching frequency (F1) of switching elements included in the driver block. The switching frequency (F1) is less than a resonant frequency (FR) of the piezoelectric transformer; for example, the switching frequency is a sub-harmonic of the resonant frequency (FR).

A piezo-electric tag in the form of a card has a first dipole antenna, a first rectification circuit, a piezo-electric transformer, a second rectification circuit, and a transponder circuit. In operation, the antenna receives incoming radiation and generates a corresponding signal which propagates to the first circuit which demodulates and filters it to generate a signal which is applied to the transformer to excite it. The transformer increases the voltage amplitude of the signal by generating a relatively higher voltage amplitude signal which is used in the tag to generate a signal for supplying power to the transponder. The transformer provides voltage magnitude enhancement to generate potentials suitable for operating active electronic circuits incorporated into the tag. The tag can be personnel wearable and even adapted for permanent inclusion into biological systems.

Method of tuning a drive circuit for a cold cathode fluorescent lamp (CCFL). The drive circuit includes a piezoelectric transformer coupled to an output of first and second transistors. The frequency of drive signals to the first and second transistors are varied until about a ninety degree phase relationship is achieved between the frequency of the drive signals and a frequency of voltage across a resistor connected to the CCFL is achieved. Alternatively, the frequency of the drive signals provided to the first and second transistor is adjusted as needed to achieve maximum output voltage.

In an ion generator comprising a discharge needle 2, an opposed electrode 3 opposite the discharge needle 2 and an AC high voltage power source 4, for generating positive and negative air ions by giving rise to a corona discharge when a high voltage is applied by the AC high voltage power source 4 between the discharge needle 2 and the opposed electrode 3, the AC high voltage power source 4 comprises a high frequency oscillator 7 and a piezoelectric transformer 9, and outputs a high frequency voltage. An insulator 5 is placed intervening between the high voltage output line 4a of the AC high voltage power source 4 and the discharge needle 2 to capacitance-couple them, and the discharge needle 2 is enabled to discharge electricity. Preferably, the surface of the opposed electrode 3 should be covered with an insulator. This enables the balance between positive and negative air ions and its stability to be improved while reducing the hardware configuration in size and weight.

This disclosure provides implementations of electromechanical systems piezoelectric resonator transformers, devices, apparatus, systems, and related processes. In one aspect, a transformer includes a piezoelectric layer; a first conductive layer arranged over a first surface of the piezoelectric layer including a first set of electrodes and a second set of electrodes interdigitated with the first set. The transformer includes a second conductive layer arranged over a second surface including at least a third set of electrodes. In some implementations, the transformer includes a first port capable of receiving an input signal and to which the first set of electrodes are coupled, and a second port capable of being coupled to a load and of outputting an output signal, the second set of electrodes being coupled to the second port. Generally, a ratio of the number of electrodes of the second set to the first set characterizes a transformation ratio.

A circuit for controlling operation of a load. In one example, a MEMS switch is positioned in the circuit to place the load in one of a conducting state or a nonconducting state. A piezoelectric transformer provides a relatively high voltage output signal or a relatively low voltage output signal to control movement of the switch between a closed position, placing the load in the conducting state, and an open position. The high voltage output signal includes a frequency component in the resonant frequency range of the transformer. Control circuitry provides an input voltage signal to the piezoelectric transformer to provide the high voltage output signal or the low voltage output signal at the output terminals of the piezoelectric transformer.

A modular design for combining piezoelectric transformers is provided for high voltage and high power conversion applications. The input portions of individual piezoelectric transformers are driven for a single power supply. This created the vibration and the conversion of electrical to electrical energy from the input to the output of the transformers. The output portions of the single piezoelectric transformers are combining in series and / or parallel to provide multiple outputs having different rating of voltage and current,

To provide a piezoelectric transformer drive method and a drive circuit which is capable of preventing breakdown of the piezoelectric transformer due to excessive oscillation on its activation and of obtaining a high efficiency. Controller controlling the load power to a constant value is provided. The controller is controlled in such a manner that the driving of the piezoelectric transformer is initiated at a frequency higher than the resonating frequency on its activation and thereafter the drive frequency is gradually lowered without passing through the resonating frequency of the piezoelectric transfer on its activation.

A resonant DC / AC inverter includes a DC power source providing a DC voltage, a half-bridge power switch circuit electrically connected to the DC power source being operative to convert the DC voltage to an AC voltage, a resonant tank electrically connected between an output of the half-bridge power switch circuit and an input of a load being operative to boost and filter the AC voltage to generate an AC power voltage supplied to the load, and a controller being operative to detect a magnitude of current in the load and a magnitude of a voltage across the load and to generate pulse waveforms for turning on and off the half-bridge power switch circuit, wherein the controller substantially instantaneously varies a frequency of the pulse waveforms and a duty cycle of the pulse waveforms so as to operate the resonant DC / AC inverter near a neighborhood of a resonant frequency of the resonant tank regardless of a conduction state of the load and improve the efficiency of the inverter regardless of the higher DC voltage applied to the inverter. Particularly, the resonant DC / AC inverter utilizes a piezoelectric transformer to supply power to a fluorescent lamp which is wildly employed in display panels and is extensively used to provide backlighting for liquid crystal displays (LCDs), especially for backlighting LCD monitors and LCD televisions.

The invention relates to a plumbum niobate-nicklate (PNN)-plumbum zirconate titanate (PZT) piezoelectric ceramic capable of being sintered at low temperature. The chemical formula of the PNN-PZT piezoelectric ceramic is 0.3Pb(Ni1 / 3Nb2 / 3)O3-0.7Pb(Zr0.44Ti0.56)O3+xCuO, wherein x is more than 0 and is less than or equal to 0.03. According to the PNN-PZT piezoelectric ceramic, a 0.3 PNN-0.7 PZT ternary piezoelectric ceramic material with high comprehensive performance is prepared by the conventional oxide mixing method and sintering CuO at low temperature under normal pressure on the basis of a Pb(Ni1 / 3Nb2 / 3)O3-Pb(Zr0.44Ti0.56)O3 system, so that the piezoelectric ceramic which can be sintered at low temperature and has high comprehensive performance is provided. The PNN-PZT piezoelectric ceramic is mainly applied to electronic devices of multilayer piezoelectric transformers, multilayer ceramic capacitors and the like which are sintered jointly at the low temperature.

An ink-jet head includes a channel unit which includes a plurality of pressure chambers, a vibration plate stacked on the channel unit, and a piezoelectric material layer arranged on the vibration plate. The piezoelectric material layer includes a first portion functioning as a piezoelectric actuator, and a second portion functioning as a piezoelectric transformer which amplifies a driving signal to be supplied to the piezoelectric actuator. Accordingly, it is possible to realize a small-size ink-jet head with a built-in piezoelectric amplifier.

A power source device includes an oscillator generating a clock, a frequency division unit dividing the clock to output a pulse, a sequence generation unit generating sequences “N” with respect to each switching of the pulse, a frequency division ratio setting unit setting frequency division ratio, a switching element driven by the pulse, and a piezoelectric transformer outputting alternating high voltage from a secondary-side when a primary-side is applied with voltage. The generated sequence and the set frequency division ratio are compared to output the pulses of fractional-M, −M+1 frequencies. An average frequency division ratio of the pulses of fractional-M, −M+1 frequencies determined by (M×α)+(M+1)×β / (α+β), where α and β respectively represent the number of pulses of “M” and “M+1” per unit time. The average frequency division ratio and frequency division ratio become equal at a sequence generation cycle and approximated in a period shorter than the sequence generation cycle.

A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, an output voltage control circuit which controls an output voltage from the piezoelectric transformer, and includes a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal. The power supply unit also includes a driving frequency supplying circuit which generates a driving frequency signal of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the driving frequency signal to the piezoelectric transformer. The time constant of the output voltage control circuit is longer than the time constant of the output voltage detecting circuit.

With a piezoelectric transformer formed of a ferroelectric element which generates a high voltage in a secondary section upon application of an AC voltage to a primary section, ground electrodes are attached to upper and lower surfaces of the secondary section of the piezoelectric transformer via a dielectric sheet for insulation in tight contact therewith such that a dielectric barrier discharge occurs around the ground electrodes to generate positive and negative ions, and an air flow is injected from an air nozzle to flow toward a neutralized subject across the ground electrodes.

The present invention discloses a DC / AC converter in the backlight power supply system using cold cathode fluorescent lamp (CCFL). The DC / AC converter comprises a front end DC / DC converter, a full-bridge or half bridge inverter, and a piezoelectric transformer. Even with a wide range of input voltages, the front end DC / DC converter produces a predetermined DC voltage or a DC voltage with a predetermined small range and the cascaded inverter operates with a switching frequency close to the resonant frequency of the piezoelectric transformer, which helps the backlight power supply system achieve high efficiency.

The present invention relates to a piezoelectric power converter comprising an input driver electrically coupled directly to an input or primary electrode of the piezoelectric transformer without any intervening series or parallel inductor. A feedback loop is operatively coupled between an output voltage of the piezoelectric transformer and the input driver to provide a self-oscillation loop around a primary section of the piezoelectric transformer oscillating at an excitation frequency. Electrical characteristics of the feedback loop are configured to set the excitation frequency of the self-oscillation loop within a zero-voltage-switching (ZVS) operation range of the piezoelectric transformer.

A modular design for combining piezoelectric transformers is provided for high voltage and high power conversion applications. The input portions of individual piezoelectric transformers are driven for a single power supply. This created the vibration and the conversion of electrical to electrical energy from the input to the output of the transformers. The output portions of the single piezoelectric transformers are combining in series and / or parallel to provide multiple outputs having different rating of voltage and current.

A high-voltage power supply comprises the following components. A piezoelectric transformer outputs a voltage in accordance with a supplied drive frequency. A rectification part is connected to an output side of the piezoelectric transformer. A drive frequency generating part generates the drive frequency supplied to the piezoelectric transformer. A voltage detection part detects an output voltage of the piezoelectric transformer or the rectification part. A control part controls the drive frequency generating part such that a drive frequency corresponding to the output voltage detected by the voltage detecting part is generated. A first time constant, which is a time constant of the control part, is smaller than a second time constant, which is a time constant of a control target including the piezoelectric transformer and the rectification part. A third time constant, which is a time constant of the voltage detecting part, is smaller than the second time constant.

In a power supply apparatus including a plurality of power supply circuits, each of the power supply circuits has a piezoelectric transformer, a rectification element which rectifies and smoothes a voltage output from the piezoelectric transformer in accordance with a load and outputs the voltage, a voltage-controlled oscillator which controls the frequency of an output signal in accordance with an input control signal, and a power supply voltage supply element which is driven by a signal output from the voltage-controlled oscillator and supplies a power supply voltage to the piezoelectric transformer. One power supply circuit includes a resonance frequency change unit which is connected to the output side of the piezoelectric transformer. The resonance frequency change unit drives the piezoelectric transformer of the power supply circuit at a driving frequency which is different from the driving frequency of the piezoelectric transformer in another power supply circuit by shifting the peak of the resonance frequency.

In an ion generator comprising a discharge needle 2, an opposed electrode 3 opposite the discharge needle 2 and an AC high voltage power source 4, for generating positive and negative air ions by giving rise to a corona discharge when a high voltage is applied by the AC high voltage power source 4 between the discharge needle 2 and the opposed electrode 3, the AC high voltage power source 4 comprises a high frequency oscillator 7 and a piezoelectric transformer 9, and outputs a high frequency voltage. An insulator 5 is placed intervening between the high voltage output line 4a of the AC high voltage power source 4 and the discharge needle 2 to capacitance-couple them, and the discharge needle 2 is enabled to discharge electricity. Preferably, the surface of the opposed electrode 3 should be covered with an insulator. This enables the balance between positive and negative air ions and its stability to be improved while reducing the hardware configuration in size and weight.

A driving circuit for a piezoelectric transformer is provided, which is capable of driving a piezoelectric transformer at a high efficiency and with low distortion, and being miniaturized. At the commencement of lighting a cold-cathode fluorescent tube, a digital controller fixes frequencies of first and second control signals VC1 and VC2 at a predetermined frequency and controls the phase difference therebetween so that an output power of the piezoelectric transformer becomes from substantially zero to a predetermined output power. After lighting of the cold-cathode fluorescent tube, the digital controller controls the phase difference between the first and second control signals VC1 and VC2 so that current detecting data CD substantially is matched with reference data RD.

A direct current (DC)-alternating current (AC) power convertor is disclosed. The DC-AC power converting circuit may include an inverter configured to convert the DC power into first output power, a piezoelectric transforming unit including piezoelectric transformers connected in parallel to an output terminal of the inverter, and each piezoelectric transformer of the piezoelectric transformers configured to transform the first output power to second output power, and an output configured to add the second output power output from the each of the piezoelectric transformer and to output AC power, wherein each piezoelectric transformer has a resonance frequency.

A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal, and a driving frequency supplying circuit which generates the driving frequency of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the resultant driving frequency to the piezoelectric transformer. The time constant of the output voltage setting signal is longer than the time constant of the output voltage detecting circuit.

In a power supply apparatus including a plurality of power supply circuits, each of the power supply circuits has a piezoelectric transformer, a rectification element which rectifies and smoothes a voltage output from the piezoelectric transformer in accordance with a load and outputs the voltage, a voltage-controlled oscillator which controls the frequency of an output signal in accordance with an input control signal, and a power supply voltage supply element which is driven by a signal output from the voltage-controlled oscillator and supplies a power supply voltage to the piezoelectric transformer. One power supply circuit includes a resonance frequency change unit which is connected to the output side of the piezoelectric transformer. The resonance frequency change unit drives the piezoelectric transformer of the power supply circuit at a driving frequency which is different from the driving frequency of the piezoelectric transformer in another power supply circuit by shifting the peak of the resonance frequency.

A piezoelectric device that includes a base member having an opening therein and an upper layer supported by the base member. The upper layer includes a vibration portion at a location corresponding to the opening in the base member. The vibration portion includes a lower electrode, an intermediate electrode and an upper electrode that are spaced apart from one another in a thickness direction of the piezoelectric device. The upper layer includes a first piezoelectric layer disposed so as to be at least partially sandwiched between the lower electrode and the intermediate electrode, and a second piezoelectric layer disposed so as to overlap with the first piezoelectric layer and so as to be at least partially sandwiched between the intermediate electrode and the upper electrode. The first piezoelectric layer and the second piezoelectric layer are different in relative permittivity in the thickness direction of the piezoelectric device.

A high gain pulse generator includes a piezoelectric transformer (PT) that is driven by an input power stage to drive the PT at a desired PT resonant frequency such that at least one PT characteristic substantially matches at least one non-linear load characteristic such as, without limitation, a plasma load characteristic to deliver a desired pulse to the non-linear load.

To provide a corona discharge ionizer that makes it possible to use a piezoelectric transformer by adding an effective ion balance function with a simple structure without applying particular changes to the structure, and that realizes noise reduction. In a corona discharge ionizer 10, a control electrode 6 is disposed in a cylindrical portion of an air supply pipe 2 which also functions as a shield body and at a location where ions are balanced. When a cylindrical inner diameter of the air supply pipe 2 is defined as Ds and an annular outer diameter of the control electrode 6 is defined as Dc, 2Dc<Ds is satisfied.

A piezoelectric power supply has a piezoelectric transformer circuit configuration which is alterable flexibly according to varying loading power requirements. It includes a control unit (control IC), a power switch (MOSFET) and an inductor to drive a piezoelectric transformer unit to actuate a high voltage and power load such as a cold cathode fluorescent lamp. The piezoelectric transformer unit consists of a plurality of piezoelectric transformers coupled in parallel. The specification of the piezoelectric transformers (single sheet piezoelectric transformers or low level laminated piezoelectric transformers) and parallel coupling number may be altered according to the required power of the load to change the voltage and current output by the piezoelectric transformers.