Abstract: Examples are disclosed herein that relate to driving a resonant scanning mirror system using a linear LC resonant driving scheme. In one example, a resonant scanning mirror system includes a scanning mirror, first and second mirror drive elements, and a drive circuit to drive the scanning mirror at a resonant frequency. The drive circuit includes one or more signal sources configured to create a first source signal and a second source signal that is 180 degrees out of phase with the first source signal. The drive circuit further includes a buffer stage configured to receive the first and second source signals and output first and second drive signals, a first resonant LC stage configured to amplify the first drive signal for provision to the first mirror drive element, and a second resonant LC stage configured to amplify the second drive signal for provision to the second mirror drive element.

Abstract: In one embodiment, a method for managing a heatsink of an information handling system includes: determining, by a controller unit of the information handling system, that a vibration event is to occur, the vibration event associated with a vibration unit of the information handling system, the controller unit communicably coupled to the vibration unit, the vibration unit removably coupled to the heatsink; and causing, by the controller unit, the vibration unit to generate the vibration event, the vibration event causing the vibration unit to apply one or more vibrations to the heatsink, the one or more vibrations causing a boundary layer of particles to be removed from a surface of the heatsink.

Abstract: Embodiments of the disclosure provide a comb drive, a comb drive system, and a method of operating the comb drive to rotate bi-directionally in a MEMS environment. An exemplary comb drive system may include a comb drive, at least one power source, and a controller. The comb drive may include a stator comb having a first electrically conductive layer spaced apart from a second electrically conductive layer. The comb drive may also include a rotor comb having a first electrically conductive layer spaced apart from a second electrically conductive layer. The controller may be configured to apply first and second voltage levels having opposite polarities to the first and second electrically conductive layers of the rotor comb, respectively. The controller may also be configured to apply an intermediate voltage level to one of the first or second electrically conductive layers of the stator comb.

Abstract: A vehicle key capable of generating electrical energy by itself through energy harvesting, and a method of manufacturing the vehicle key are provided. The vehicle key includes a power generator including an energy generation module configured to generate electrical energy using energy harvesting and an electric condenser configured to store the generated electrical energy; an inputter configured to receive a user input; a communicator configured to communicate with the vehicle; and a controller configured to control the communicator to transmit a control signal corresponding to the received user input to the vehicle. At least one of the inputter, the communicator, and the controller may be configured to receive power from the power generator.

Abstract: A driving control apparatus is configured to control a driving unit that moves relative to each other a vibrator that is excited to vibrate by applying a first driving signal and a second driving signal that have a phase difference with each other, and a contact member that contacts the vibrator. The driving control apparatus includes a first control unit configured to control the phase difference, and a second control unit configured to control a voltage amplitude of each of the first driving signal and the second driving signal. The second control unit controls the voltage amplitude so that a change rate of the voltage amplitude increases as an absolute value of the phase difference decreases.

Abstract: A method of manufacturing a piezoelectric actuator includes preparing a laminate including a substrate, a first electrode layer disposed on the substrate, a piezoelectric layer disposed on the first electrode layer, and a second electrode layer disposed on the piezoelectric layer, and forming a contour shape of the piezoelectric layer. The forming of the contour shape includes dry etching the piezoelectric layer from the second electrode layer side to dig the piezoelectric layer halfway in a thickness direction, covering, with a resist film, a dry etched surface formed on a side surface of the piezoelectric layer by the dry etching, and wet etching the piezoelectric layer from the second electrode layer side to dig the piezoelectric layer until the first electrode layer is reached.

Abstract: A method for assessing performance of a surgical instrument including one or more drivetrains is disclosed. The method includes sensing via one or more vibration sensors vibrations generated during operation of the one or more drivetrains of the surgical instrument, generating an output signal based on the sensed vibrations, filtering the output signal to generate a filtered signal of the sensed vibrations from the one or more drivetrains, processing the filtered signal to generate a processed signal of the sensed vibrations from the one or more drivetrains, and comparing predetermined threshold values for each of an acceptable status, a marginal status, and a critical status of the surgical instrument to corresponding values of the processed signal.

Abstract: A capacitive transducer comprising a top electrode and a bottom electrode, and a sidewall between the top electrode and the bottom electrode. The sidewall is configured to separate the top electrode and the bottom electrode by a gap. There is a high contact resistance part on one or both of a bottom side of the top electrode or a top side of the bottom electrode.

Abstract: A driving system for driving piezoelectric pump includes one or more mechanical devices and a driving circuit system electrically connected to the at least one mechanical device. The driving circuit system includes a pump-driving unit, a linear voltage-stabilizing unit, a microcontroller unit, a current-sensing unit, and a connection unit. The microcontroller unit generates a first signal, a second signal, and a third signal, and the pump-driving unit receives these signals to drive the mechanical device. The current-sensing unit receives a fourth signal transmitted by the pump-driving unit to obtain an actuation current value of the mechanical device. The linear voltage-stabilizing unit, the current-sensing unit, and the microcontroller unit are coupled to each other through a fifth signal and a sixth signal. The connection unit and the microcontroller unit are coupled to each other through a reset signal, a seventh signal, and an eighth signal provided by the microcontroller unit.

Abstract: An electronic watch includes a power source, an electrostatic motor including a rotor in which a plurality of electret films are arranged in a rotational direction and a plurality of fixed electrodes arranged in the rotational direction at positions facing the rotor, a hand rotating in conjunction with the rotation of the rotor, and a motor control circuit controlling the electrostatic motor. The motor control circuit selectively executes a hand movement mode for rotating the hand and a stop mode for keeping the hand stationary. In the stop mode, the motor control circuit keeps the rotor stationary through electrostatic forces exerted on the electret films from the fixed electrodes with the polarities of the fixed electrodes maintained.

Abstract: A converter circuit includes first and second electronic switches coupled at an intermediate node, with an inductor coupled between the intermediate node and an output node. Switching drive control circuitry causes the first and the second electronic switch to switch between a conductive state and a non-conductive state. The drive control circuitry includes a first feedback signal path to control switching of the first and the second electronic switch as a function of the difference between a feedback signal indicative of the signal at the output node and a reference value. A second feedback signal path includes a low-pass filter coupled to the output node and configured to provide a low-pass filtered feedback signal resulting from low-pass filtering of the output signal. The second feedback signal path compensates the feedback signal as a function of the difference between the low-pass filtered feedback signal and a respective reference value.

Abstract: A zero-voltage zero-current soft switching type driving method for an ultrasonic motor is provided, relating to the technical field of driving of a two-phase actuator. The disclosure solves the problems of high loss, high heat amount and the like in a traditional ultrasonic motor driving circuit. The method provided realizes resonance between series inductors and buffer capacitors by means of an optimal design of the inductance of matching inductors, the capacitance of buffer capacitors, a dead time value and a delay time value, thereby causing a power tube to realize zero-voltage and zero-current switching. Two signal input ends of a two-phase pseudo full bridge inverter are connected to a power grid, and two signal output ends of the two-phase pseudo full bridge inverter are respectively connected to two signal input ends of a matching circuit; and the output ends of the matching circuit are respectively connected to a two-phase ultrasonic motor.

Abstract: A control method of a piezoelectric driving device which includes a vibrator including a piezoelectric element and vibrating by application of a drive signal to the piezoelectric element, a driven unit moving by the vibration of the vibrator, a drive signal generation unit generating the drive signal based on a pulse signal, the control method including: stopping the application of the drive signal to the piezoelectric element at the time when a driving speed of the driven unit is a reference speed, in a case of stopping driving of the driven unit.

Abstract: A piezoelectric drive device includes a vibrator having a vibrating portion including a piezoelectric element, and a convex portion placed in the vibrating portion, an urging member including a base, a holding portion holding the vibrator, and a spring portion coupled to the base at one end and coupled to the holding portion at another end and urging the convex portion toward a driven unit, wherein d1>d2 in a natural state in which the vibrator is not urged by the urging member, where a separation distance between the one end and the convex portion along directions of the longitudinal direction is d1 and a separation distance between the other end and the convex portion is d2, and |d1?d2| in an urging state in which the vibrator is urged toward the driven unit by the urging member is smaller than |d1?d2| in the natural state.

Abstract: A brush includes a head with bristles, an actuator that expands and contracts in accordance with an electric signal, a connection member that transmits vibration of the actuator to the head, and a body including a housing that houses the actuator. The direction of reciprocal vibration of the head is at a predetermined angle relative to the direction of extension of the housing.

Abstract: Described herein are methods and systems for controlling a sensor assembly with a plurality of same type sensors. Sensors are operated in active and inactive states and have a corresponding performance parameter and reliability parameter that may be determined. The activation state of at least one of the sensors is changed based on an operational parameter. The performance parameter and/or the reliability parameter can then be updated.

Abstract: There is provided a control method for a piezoelectric driving device including a vibrating body including a piezoelectric element for driving and configured to vibrate when a driving signal is applied to the piezoelectric element for driving, a section to be driven that is driven by the vibration of the vibrating body, and a driving-signal generating section configured to generate the driving signal using a pulse signal generated based on a target pulse duty ratio. When the target pulse duty ratio is smaller than a predetermined value, the driving signal generated by the driving-signal generating section is an intermittently generated periodic signal.

Abstract: Disclosed is a driver stage for activating a first ultrasonic transducer and a method for the operation thereof. The driver stage comprises a first charge pump or power source and a first capacitor. The driver stage also comprises first means for charging the first capacitor with electrical energy from the charge pump and second means for connecting the first capacitor and ultrasonic transducer to different polarities. The first means do not charge the first capacitor with energy from the charge pump or power source when the first capacitor is connected to the ultrasonic transducer by the second means.

Abstract: An electrostatic zipping actuator includes a primary electrode, a secondary electrode overlying the primary electrode, a dielectric layer located between and abutting at least a portion of the primary electrode and the secondary electrode, and a dielectric fluid disposed at least at a junction between the dielectric layer and one of the electrodes, where an average total thickness of the dielectric layer is less than approximately 10 micrometers.

Abstract: A socket includes a housing configured to receive a removable Data Storage Device (DSD) and a Thermal Interface Material (TIM). An assembly of the socket is attached to the housing and configured to expand due to heat. In a thermally expanded state, the assembly causes the TIM to come into contact with the removable DSD to draw heat away from the removable DSD. According to another aspect, a retaining strip or assembly is attached to a housing in a configuration such that the retaining strip or assembly expands due to heat to increase a resistance to removal of the removable DSD from the housing when the retaining strip or assembly is in a thermally expanded state.

Abstract: A piezoelectric generator is specified, comprising a deformation body, which spans a projection surface and is embodied with a setpoint pressure surface situated opposite the projection surface, wherein the projection surface can be converted from a smaller projection surface when not loaded under pressure into a larger projection surface when pressure is applied to the setpoint pressure surface substantially perpendicular to the projection surface, and a spring effect is provided which counteracts an application of pressure to the setpoint pressure surface, wherein an electromechanical transducer element comprising a piezoelectric material wholly or partly spans the projection surface, such that the transducer element is embodied in an expandable fashion upon pressure being applied to the deformation body, and electrical microenergy can be generated by means of the piezoelectric material.

Abstract: A system includes an apparatus and a processor. The apparatus includes a set of actuator elements that move between two positions. Each actuator element is comprised in: exactly one first subset out of a plurality of non-empty first subsets and exactly one second subset out of a plurality of non-empty second subsets. The processor is configured to generate one or more control commands for a group of subsets out of the first and the second pluralities of subsets in response to a number of moving elements which, if released from the first extreme position during a second sampling cycle, enables production by the apparatus during the second sampling cycle of a sound.

Abstract: A vibration motor controller configured to cause a vibrating member in which a vibration is excited based on two frequency signals having a phase difference to move relatively to a contact member, the vibration motor controller including: a memory configured to store a speed characteristic of the vibrating member with respect to a frequency of the two frequency signals; a controller configured to control a speed of the vibrating member by changing the frequency and/or a phase difference of the two frequency signals; a detector configured to detect the speed; and a changing unit configured to acquire change amount and change direction of the speed characteristic based on comparison between the speed detected by the detector and the speed characteristic stored in the memory, and change an activation frequency being a start point of control conducted by the controller based on the change amount and the change direction.

Abstract: The present invention provides a driving apparatus capable of suppressing the operation noise. A driving apparatus comprises a piezoelectric element expanding and contracting in accordance with a driving signal; a supporting shaft connected to said piezoelectric element; a movable body frictionally engaged with said supporting shaft and capable of moving along said supporting shaft; and a driving portion applying said driving signal including a first driving signal which moves said movable body towards a first direction to said piezoelectric element, wherein said driving portion can repeatedly apply said first driving signal against said piezoelectric element by taking a first time in between, and said first driving signal comprises a main driving waveform group which moves said movable body to said first direction, and a sub driving waveform group which is placed after said main driving waveform group by having a second rest time shorter than said first time in between.

Abstract: An identification method is an identification method for use in an identification apparatus that identifies types of brushless DC motors each including a circuit board on which a terminal for tachometer is mounted. The duty ratios of pulses outputted from the terminals for tachometer vary among multiple types of brushless DC motors. The identification method includes: supplying a power supply voltage from the identification apparatus to a brushless DC motor; inputting pulses outputted from the terminal for tachometer of the circuit board to the identification apparatus; obtaining the duty ratio of the pulses as a unique information piece of the brushless DC motor; and identifying the type of the brushless DC motor based on the unique information piece of the brushless DC motor.

Abstract: An inverse electrowetting harvesting and scavenging circuit includes a first substrate having first and second surfaces. An electrode is formed proximate the first surface and includes an insulating layer covering a surface of the electrode. An electromechanical systems device includes a moveable mass extending over the first surface of the first substrate that may be displaced relative to the first substrate in three dimensions responsive to external forces applied to the moveable mass. The movable mass includes a moveable electrode and a conductive fluid is positioned between the insulating layer of the electrode and the movable electrode.

Abstract: The invention relates to transformers. More particularly, the invention relates to transformers using (preferably electrostatic and more preferably dielectric elastomer) transducers such as generators and actuators. The invention further provides a priming circuit therefor.

Abstract: The invention provides circuits, systems and methods for dielectric elastomer device (DED) self-sensing. The circuit comprises a first DED coupled or adapted for coupling to a first voltage source (for providing an actuating or priming signal, for example); a current sensor provided in series with the first DED; and an oscillating signal source coupled to the first DED and adapted to cause an oscillation in a voltage across the DED, wherein the oscillating signal source is decoupled from the first voltage source.

Abstract: There is provided a three-dimensional triboelectric energy generator comprising: a moving object; at least two triboelectric energy generator modules defining at least two planes respectively, wherein the moving object is disposed between the least two planes; and at least two elastic members configured to couple the moving object to the at least two triboelectric energy generator modules respectively, wherein a movement of the moving object allows each of the at least two triboelectric energy generator modules to generate a triboelectric energy.

Abstract: A controller for controlling a micromechanical actuator having a setpoint input for receiving a setpoint signal, an actual-value input for receiving an actual-value signal, a setpoint filter to attenuate a first predefined frequency or a first predefined frequency band in the received setpoint signal to generate a filtered setpoint signal, a differentiator to generate a time derivative of the received actual-value signal; a controller core to generate a manipulated variable signal based on a system deviation between the filtered setpoint signal and the actual-value signal; a phase rotation element to modify the phase of the difference between the manipulated variable signal and the derivative of the actual-value signal for a second frequency or in a predefined second frequency band to generate a modified manipulated variable signal; and a first manipulated variable filter to suppress a predefined third frequency in the modified manipulated variable signal.

Abstract: A variable capacitor, including: two movable plates, two poles, and one rotary shaft. The two movable plates are conductor belts, and the conductor belts are sheathed in insulators. The two poles are conductors, and each is capable of rotating around an axis thereof. First ends of the two movable plates are connected via the insulators and fixed on the rotary shaft, and second ends of the two movable plates are connected to the two poles, respectively. A conductor member of the two movable plates directly contacts the two poles. The lengths of the two movable plates are identical, and are greater than the distance from one pole to the rotary shaft.

Abstract: Various embodiments provide an optical image stabilization circuit including a drive circuit having a power waveform generator and a power waveform conversion circuit. The power waveform generator generates a power waveform. The power waveform conversion circuit converts the power waveform to a power drive signal. An actuator is then driven by the power drive signal to move a lens accordingly and compensate for any movements and vibrations of a housing of the lens.

Abstract: Various embodiments provide an optical image stabilization circuit including a drive circuit having a power waveform generator and a power waveform conversion circuit. The power waveform generator generates a power waveform. The power waveform conversion circuit converts the power waveform to a power drive signal. An actuator is then driven by the power drive signal to move a lens accordingly and compensate for any movements and vibrations of a housing of the lens.

Abstract: A vibration driving device that is capable of exciting a vibration of desired amplitude with a low voltage. A vibration body has a plate-like elastic body and an electro-mechanical energy conversion element that is joined to the elastic body. A control unit excites a vibration in a first vibration mode and a vibration in a second vibration mode in the vibration body by applying alternation voltages to the electro-mechanical energy conversion element. Orders or numbers of nodes of the vibrations in the first and second modes in a first direction that intersects perpendicularly with a thickness direction of the elastic body are mutually different by one. And orders or numbers of nodes of the vibrations in the first and second modes in a second direction that intersects perpendicularly with the thickness direction of the elastic body and the first direction are mutually different by one.

Abstract: This disclosure provides systems, methods and apparatus for wireless power transfer and particularly wireless power transfer to remote system such as electric vehicles. In one aspect an apparatus for use with a wireless power transfer transmitter device comprising a first inductive element for generating a magnetic field, is provided. The apparatus comprises a direct current (DC) power source having an adjustable output voltage. The apparatus also comprises an inverter configured to convert the adjustable output voltage of the DC power source to alternating current. The apparatus also comprises at least one controller configured to receive an indication of current in the first inductive element and control the output voltage of the DC power source in response to the indication of current in the first inductive element. The apparatus reduces distortion signals in the alternating current output of the inverter while maintaining current in the inductive element substantially constant.

Abstract: A motor controller for an electric vehicle sufficiently reduces vibration components caused by torque ripples passing through a resonance frequency of a vehicle body. The motor controller includes motor torque setting means for generating a first torque command, based on vehicle information, rotation position detection means for detecting a rotation position of the motor, rotation speed calculation means for calculating a rotation speed from a rotation position signal, a high-pass filter that extracts an AC signal component of a rotation speed signal, and a resonance suppression gain circuit that outputs a resonance suppression signal. A signal in which the resonance suppression signal is added to or subtracted from the first torque command is used as a second torque command so as to perform drive control for the motor.

Abstract: A system and method that bends a reticle and senses a curvature of a bent reticle in real-time. The system includes movable reticle stage, reticle vacuum clamps, sensor systems, and reticle bender. The reticle bender comprises piezo actuators. The sensor systems comprises measurement targets and corresponding sensors. The sensors are attached to the movable reticle stage and the measurement targets are attached to the reticle clamps, the reticle bender, or on reticle surfaces. The system is configured to determine a width of the reticle or distance between measurement targets at opposing ends of the reticle, measure a first rotational angle at a first end of the reticle, and measure a second local rotational angle at a second end of the reticle that is opposite to the first end. Based on the width or distance and the first and second angles, a field curvature of the reticle is determined.

Abstract: A system for synchronizing instruments in a drill pipe to detect formation characteristics comprises at least one first transmitter for transmitting a first signal, at least one first receiver for receiving a second signal having information based on the first signal, at least one acoustic transmitter for transmitting an acoustic signal, and at least one acoustic sensor electrically connected to one of the at least one first transmitter and the at least one first receiver, the at least one acoustic sensor for sensing the acoustic signal for synchronizing the at least one first transmitter and the at least one first receiver.

Abstract: A device for applying decoration to a nail. The device includes an elongated member having a first end having a mounting feature thereon, the mounting feature configured to maintain the first end of the device in a fixed position, and a generally opposite, free-floating end configured to be coupled to a nail decoration, the free-floating end configured to provide controlled movement of the decoration. The elongated member is configured to inhibit unintentional movement thereof.

Abstract: A piezoelectric actuator includes a vibrating body including a piezoelectric device; a driving circuit that supplies a driving signal to the piezoelectric device; a phase difference detecting circuit that detects a phase difference between the driving signal and a detection signal detected based on vibration of the vibrating body; and a frequency controller that controls the frequency and power of the driving signal, wherein the frequency controller sets the power to an upper limit voltage value when the frequency is changed so that the phase difference falls within a predetermined range and sets the voltage to a lower limit voltage value smaller than the upper limit voltage value when the phase difference is outside the predetermined range.

Abstract: When a vibration-type actuator is in a non-driving period, at least one of a voltage amplitude and a phase difference of an alternate signal applied to an electrode of a piezoelectric element is set to be equal to a minimum value or a maximum value of a dead zone in terms of the voltage amplitude or the phase difference.

Abstract: A switched resonant power amplifier system for ultrasonic transducers is disclosed. The system includes an amplifier that receives and processes a driver output signal for generating a drive signal that is provided to an ultrasonic device for controlling output of the ultrasonic device. An output control circuit receives and processes a signal related to a feedback signal generated by the ultrasonic device and a divider reference signal, and generates a compensated clock signal that is adjusted for at least one of phase and frequency differences between the received feedback signal and the divider reference signal. A compensated drive circuit receives and processes the compensated clock signal for generating the divider reference signal, and for generating the driver output signal.

Abstract: Method for controlling a piezoelectric actuator acting on valve elements to open or close a fuel injector respectively allowing or preventing fuel injection into a combustion chamber of an engine, the method includes: applying to the piezoelectric actuator a nominal electrical charge to open the injector, as a function of the torque required and the engine speed, to open the valve elements for fuel injection, thereafter applying to the actuator at least one electrical polarization charge, to polarize the actuator during an opening phase of the injector and fuel injection into the combustion chamber, thereafter commanding the closure of the injector by applying to the actuator at least one electrical discharge to close the valve elements, the step of applying the electrical polarization charge including a prior step of increasing the value of the charge current to a value greater than that of the nominal charge.

Abstract: A system for driving a piezoelectric load includes a direct current (DC) voltage source and a bi-directional DC-to-DC converter having a primary side coupled to the DC voltage source and a secondary side and comprising a control input configured to receive a first control signal configured to control conversion of a first voltage on the primary side of the bi-directional DC-to-DC converter to a second voltage on the secondary side of the bi-directional DC-to-DC converter. The driver system also includes a capacitor coupled to the secondary side of the bi-directional DC-to-DC converter and configured to remove a DC offset of the second voltage and includes a reactive load having a first terminal coupled to the capacitor and a second terminal coupled to the secondary side of the bi-directional DC-to-DC converter.

Abstract: There are provided an apparatus for driving a piezo actuator and a method of driving the same. The apparatus includes: a control unit generating a digital control signal and converting the digital control signal into an analog control signal; a driving unit amplifying and not inverting the analog control signal to generate a first driving signal and amplifying and inverting the analog control signal to generate a second driving signal, with respect to a predetermined common voltage, and applying the first and second driving signals to both terminals of a piezo actuator; and an offset determining unit determining an offset in the first and second driving signals based on a voltage according to a current flowing in the piezo actuator, wherein the control unit generates the digital control signal to have an intermediate level in a predetermined offset detection section.

Abstract: A method for driving a piezoelectric transducer is provided. An input signal is received. At least one of a plurality of modes is selected for a buck-boost stage from a comparison of a desired voltage on a capacitor to a first threshold and a second threshold, where the desired voltage is determined from the input signal. The piezoelectric transducer is then driven substantially within the audio band using the desired voltage on the capacitor using an H-bridge that changes state with each zero-crossing.

Abstract: The present invention relates to an electromechanical transducer capable of arbitrarily varying the amount of deflection of a vibrating membrane for every element. The electromechanical transducer includes a plurality of elements including at least one cell that includes a first electrode and a second electrode opposed to the first electrode with a gap sandwiched therebetween and a direct-current voltage applying unit configured to be provided for each element and to separately apply a direct-current voltage to the first electrodes in each element. The first electrodes and the second electrodes are electrically separated for every element.

Abstract: A device for driving a piezo-actuator comprises: a signal generating unit for generating signals having a constant frequency; and a modulation unit for modulating the signals generated from the signal generating unit and outputting the modulated signals, wherein the modulation unit comprises a density modulation unit which performs a first mode for repeating an operation for outputting an input signal at a first constant number and an operation for blocking the input signal at a second constant number, and which performs a second mode for repeating an operation for outputting the input signal during a first period and an operation for blocking the input signal during a second period. The device for driving the piezo-actuator and the method therefor can reduce the noise generated when the piezo-actuator for an automatic focus function of a camera is driven.

Abstract: A power supply apparatus with a plurality of power supply circuits each having a piezoelectric transformer and a voltage-controlled oscillator which generates a signal at an operating frequency used to drive the piezoelectric transformer in accordance with a control signal, includes a frequency-dividing circuit which divides the operating frequency generated by a voltage-controlled oscillator in at least one power supply circuit, and outputs a signal at a driving frequency to drive a piezoelectric transformer in the one power supply circuit. When at least one power supply circuit and remaining power supply circuits output voltages, the operating frequency generated by the voltage-controlled oscillator in the one power supply circuit is controlled to be higher than the operating frequency generated by the voltage-controlled oscillator in another power supply circuit.

Abstract: A power supply apparatus with a plurality of power supply circuits each having a piezoelectric transformer and a voltage-controlled oscillator which generates a signal at an operating frequency used to drive the piezoelectric transformer in accordance with a control signal, includes a frequency-dividing circuit which divides the operating frequency generated by a voltage-controlled oscillator in at least one power supply circuit, and outputs a signal at a driving frequency to drive a piezoelectric transformer in the one power supply circuit. When at least one power supply circuit and remaining power supply circuits output voltages, the operating frequency generated by the voltage-controlled oscillator in the one power supply circuit is controlled to be higher than the operating frequency generated by the voltage-controlled oscillator in another power supply circuit.