Abstract: The position and speed and, in some embodiments, direction of rotation of a motor for turning the rod of an object such as a window covering is determined by placing a braking magnet next to the motor and a piezoelectric element between the braking magnet and motor. As the motor rotates, the piezoelectric element generates a signal that can be used to determine the speed of rotation and also the position of the motor (and, hence, the position of the object being moved). The magnet brakes the motor from turning under the weight of the object when the motor is deenergized.

Abstract: A method of extracting power includes coupling a transducer that converts mechanical power to electrical power to a disturbance; coupling an electrical circuit to the transducer such that a peak voltage experienced by the transducer is greater than two times higher than any peak voltage of an open circuit transducer due to the disturbance alone; extracting power from the transducer using the electrical circuit, and storing extracted power. Power is extracted from the transducer and applied to the transducer during different intervals in the course of the disturbance. A system for extracting power includes a transducer, an electrical circuit, and a storage element for storing extracted power.

Abstract: This disclosure relates to a technique for smoothly carrying out an acceleration operation and a deceleration operation for a vibration type actuator to prevent a situation where in starting the vibration type actuator, a drive frequency is reduced to become lower than a resonance frequency to stop the vibration type actuator. A first counter performs up-count from a first value to a second value larger than the first value at predetermined time intervals in accelerating the vibration type actuator. A rate multiplier outputs a clock signal having a frequency corresponding to the count value. A second counter measures a period of a pulse signal, the period being adapted to change in correspondence to a drive speed of the vibration type actuator, by counting the clock pulses. The drive speed of the vibration type actuator is controlled such that the measured pulse period becomes a predetermined target value.

Abstract: To provide a control system provided with a positioning mechanism including plural ultrasonic motors in the device, which can keep good operational stability as compared with a conventional system with a servo mechanism, is of an energy saving type suppressing power consumption and is compact in structure including the motor and a control circuit therefor. A control circuit in a control system of the present invention uses a common drive control circuit for a plurality of ultrasonic motors among the positioning mechanisms in which when the drive control circuit inputs a signal that specifies any ultrasonic motor and a desired-position designation signal, the drive control circuit conducts control operation that transmits an on signal to a driver of the subject motor to start the driving, and stops the driving when the motor reaches a desired position while receiving a position detection signal.

Abstract: The invention describes a method and an apparatus for charging a piezoelectric element, for example, used as an actuator in a fuel injection system of an internal combustion engine. The method and apparatus are characterized in that the piezoelectric element is activated by an activation voltage having a value set as a function of manufacturing characteristics of the particular piezoelectric element and based upon, for example, a correction value for injected fuel volume.

Abstract: An apparatus for electrically stimulating a smart material includes a controllable power source for charging the smart material and/or switching circuitry for discharging the smart material. The controllable power source includes a regulated DC to DC converter having controllable drive circuitry associated therewith. The drive circuitry can be self-oscillating through associated feedback means. The switching circuitry can be responsive to one or more control signals.

Abstract: A piezo actuator system, is presented herein. A piezo actuator system comprises a number of piezo actuators which may lengthen and shear. Using the lengthening and shearing, the piezo actuator system grips and moves an object in response to a first and a second control signal, respectively. The possible displacement of the object is limited by the maximum shear of the piezo actuators. To increase the possible displacement, the piezo actuators may be controlled to perform a linear shear sequence or a shuffle sequence. During the linear shear sequence, the object is moved; during the shuffle sequence the object is substantially stationary, while the piezo actuators are repositioned with respect to the object, after which the object may be moved further using the linear shear sequence.

Abstract: A system for obtaining inline sensory feedback from an electroactive polymer based transducer for use in feedback control applications is disclosed. Specifically a method of obtaining sensory feedback from an electroactive polymer based transducer includes the steps of: receiving a user input in a control system, combining it with a control system feedback signal from a sensory feedback circuitry and producing a control signal; receiving the control signal in an amplifier and sensory tone generator, combining it with an amplifier feedback signal from the sensory feedback circuitry and producing a power signal; receiving the power signal and an environmental disturbance in an electroactive polymer transducer and sensory circuitry and responsive to the user input producing a sensory signal; receiving the sensory signal in the sensory feedback circuitry and producing the control system feedback signal and the amplifier feedback signal; and producing a data output in the control system.

Abstract: A power output stage for capacitive loads includes: an energy storage inductance, having one end connected to a reference potential and an opposite end connected on the input side to a power supply connection and on the output side to a secondary energy storage capacitance; a primary energy storage capacitance is connected upstream of the energy storage inductance on the input side, and connected on the input side via a primary switching element with a reference potential, and a secondary switching element connected in series with the secondary energy storage capacitance (4), characterized in that the input of the power output stage is clocked by an additional switch.

Abstract: An ultrasonic-actuator driving apparatus includes an ultrasonic actuator including a transducer and a driven body that is in contact with the transducer, the transducer to which a frequency signal is applied friction-driving the driven body; an original-signal outputting unit for outputting an original signal; a waveform averaging unit for averaging the original signals during a predetermined period to calculate average-waveform data; a position detecting unit for detecting an absolute position of the driven body with respect to the transducer; a position averaging unit for averaging the absolute positions during a predetermined period to calculate average-position data; a control-signal calculating unit that generates a control signal for controlling the frequency of the original signal based on the average-waveform data and the average-position data and supplies the control signal to the original-signal outputting unit; and a driving unit for generating the frequency signal based on the original signal and

Abstract: Provided is a control device for a vibration type actuator having an elastic member fixed with an electro-mechanical energy conversion element, and a vibration member that generates a vibration on a surface of the elastic member by supplying a drive signal to the electro-mechanical conversion element, the control device including: a drive circuit that supplies a periodic signal to the electromechanical energy conversion element, a state detecting circuit that detects a drive state of the vibration member and outputs a waveform signal representing the detected drive state, an inclination detecting circuit that detects an inclination of a waveform in a given level of the waveform signal, and a control circuit that controls the drive circuit on the basis of an output signal from the inclination detecting circuit.

Abstract: The invention utilizes harmonics of certain clamped ultrasound transducers to generate ultrasound within the liquid of an ultrasonic tank and in a frequency range of between about 100 khz to 350 khz (i.e., “microsonic” frequencies). The application of microsonic frequencies to liquid preferably occurs simultaneously with a sweeping of the microsonic frequency within the transducer's harmonic bandwidth to reduce or eliminate (a) standing waves within the liquid, (b) other resonances, (c) high energy cavitation implosion, and (d) non-uniform sound fields, each of which is undesirable for cleaning and/or processing of semiconductor wafers and other delicate parts. The invention can also drive ultrasonic transducers such that the frequency of applied energy has a sweep rate within the ultrasonic bandwidth of the transducers; and that sweep rate is also varied so that the sweep rate is substantially non-constant during operation.

Abstract: One aspect of the invention relates to a composite member for a resonator having an active piezoelectric element and a passive piezoelectric element. The active piezoelectric element causes the resonator to vibrate and detects the frequency of the vibration. The passive piezoelectric element changes the frequency of the vibration. Another aspect of the invention relates to a method for controlling a resonator with composite member having a substrate carrying a composite piezoelectric element. The composite piezoelectric element includes an actuator element, a sensor element and a passive element. The method comprises inducing a resonance within the composite member with the actuator element, detecting the resonance with the sensor element, and altering the resonance by altering the electromechanical coupling of the passive element. Additional aspects and benefits of the invention are also given.

Abstract: A piezoelectric transformation driving apparatus for driving elements or products to be driven by a high or a low voltage includes a driving module consisting of a pulse-width modulation (PWM) control unit and a single driving unit. The driving module outputs driving signals of the same phase and the same frequency to drive a plurality of transformation units, a plurality of piezoelectric units and a plurality of loads.

Abstract: A device with a piezoelectric actuator (1) comprises two faces (2, 3) and two electroconductive contact paths (4, 5), each traversing the actuator (1) starting from at least one face (3). The actuator is clamped between two metallic plates (6, 7), each arranged against a face (2, 3). The piezoelectric actuator further comprises an electroinsulating layer (8) arranged between each face 92, 3) and the corresponding metallic plate (6, 7).

Abstract: A piezoelectric fuel injection system and a method of controlling same, the system including a piezoelectric fuel injector having a piezoelectric element, a power source adapted to provide power to the piezoelectric element to actuate the piezoelectric fuel injector, and a controller adapted to cyclically modulate power provide to the piezoelectric element by the power source during at least a portion of the injection event. The controller cyclically modulates the power between a predetermined first voltage and a predetermined second voltage that is less than the first voltage to control the rate of fuel injected by the piezoelectric fuel injector during the portion of the injection.

Abstract: A mover assembly (16) that moves or positions an object (12) includes a mover output (226), an actuator (230), and a measurement system (20). The mover output (226) is connected to the object (12), and the actuator (230) causes the mover output (226) to rotate about a first axis and move along the first axis. In this embodiment, the measurement system (20) directly measures the movement of the mover output (226) and provides feedback regarding the position of the mover output (226).

Abstract: A drive system is provided for a resonating probe device, such as a scanning probe microscope, wherein the amplitude of the drive signal is controlled by feeding back a phase shifted and amplified component of the amplitude of oscillation of the resonating element. Means are provided for electronically enhancing the quality factor of a resonating probe device when operated in a liquid environment. Such enhancement of the quality factor improves the sensitivity of the probe device.

Abstract: In a system for overcoming or at least damping oscillations in or through channels (9) which carry fluid in a component, in particular coolant in cooling channels in an optical element (1), in particular a projection objective lens (1a) for semiconductor lithography, oscillations which occur are detected and evaluated by sensors (5), after which the result is passed, in the form of an adaptronic control loop to piezoelectric elements (9), which are integrated in the optical element, and are in the form of thin plates, films or layers which, when activated, produce the oscillations or frequencies which counteract oscillations and natural frequencies produced by the turbulence.

Abstract: A circuit configuration, in particular, a switch-mode power supply, includes a transformer device and at least one semiconductor component to provide a particularly space-saving configuration having little susceptibility to interference, and with as little stray inductance as possible. The transformer device is in the form of an electromechanical conversion device, in particular, a piezo-transformer or the like, with, in particular, at least one connection of the transformer device forming a substantially mechanically identical connection to a connection of at least one semiconductor component.

Abstract: The invention relates to the return stroke between an actuator and an element. In order to displace the element the actuator (A) is impinged upon by a control voltage (ANS). The control voltage (ANS) is selected in such a manner that it is dependent on the size of return stroke in order to compensate the alteration in the return stroke.

Abstract: A control apparatus for a vibration type actuator is disclosed, with which at least three kinds of vibrations are excited, and a desired motion can be carried out with high efficiency. The vibration type actuator includes a rotatable moving member, an elastic member contacting the moving member, and an electro-mechanical energy conversion element exciting at least three different kinds of vibrations in the elastic member by supplying at least three periodic signals having different phases. The control apparatus includes a rotation axis determining unit, a parameter determining unit and a control circuit. The rotation axis determining unit determines a rotation axis for rotating the moving member. The parameter determining unit determines, by using an inverse model, phase and amplitude of the periodical signals.

Abstract: A single piezoelectric is excited at a first frequency to cause two vibration modes in a resonator producing a first elliptical motion in a first direction at a selected contacting portion of the resonator that is placed in frictional engagement with a driven element to move the driven element in a first direction. A second frequency excites the same piezoelectric to cause two vibration modes of the resonator producing a second elliptical motion in a second direction at the selected contacting portion to move the driven element in a second direction. The piezoelectric is preloaded in compression by the resonator. Walls of the resonator are stressed past their yield point to maintain the preload. Specially shaped ends on the piezoelectric help preloading. The piezoelectric can send or receive vibratory signals through the driven element to or from sensors to determine the position of the driven element relative to the piezoelectric element or resonator.

Abstract: A piezoactuator has a diaphragm, and the diaphragm has flat piezoelectric elements that oscillate in a longitudinal oscillation mode and a sinusoidal oscillation mode. A first electrode for detecting oscillation in the longitudinal oscillation mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed on the surface of the diaphragm. When the piezoactuator is driven with a drive signal, the phase difference of a first detection signal output from the first electrode and a second detection signal output from the second electrode is detected. The frequency at which the detected phase difference becomes the maximum phase difference is then obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.

Abstract: A thickness mode piezoelectric transducer is provided that has masses attached to opposing faces of the transformer. The end-masses increase the thickness of the transformer and decrease its resonant frequency. The end-masses increase the magnitude of resonant vibrations in the output layer(s) as well as the mechanical Q of the device to provide a low profile piezoelectric transformer with high power density. Each of the input and output portions is resonant tank circuit having a electrical resonant frequency substantially matching the mechanical resonance whereby the amplitude of the mechanical vibrations are increased. These mechanical vibrations are used in conjunction with a mechanical amplifier or horn for use of the device as a vibrational transducer.

Abstract: Piezoelectric fan assemblies are provided to provide a conduction path and forced convection for space-limited electronic devices in accordance with embodiments of the present invention. The fan blade of a piezoelectric fan is thermally coupled to the heat source, such as, but not limited to, the fins of a heat sink, the condenser of the heat pipe, and to the thermal mass of a heat spreader or block. The high amplitude resonant vibration of the fan blade causes formation of a high velocity unidirectional flow stream. Maximum airflow occurs on axes of the piezoelectric fan's centerline, relative to both width and height dimensions. Air intake is above and below the swept out plane of the fan blade. The air flow provides forced convection for the fan blade and, secondarily, for the heat source.

Abstract: A piezoelectric element driving circuit for driving a plurality of piezoelectric elements disposed in a plurality of head units is disclosed, that comprises a plurality of power amplifiers for driving the plurality of head units, a plurality of flexible flat cables for connecting the plurality of head units and the plurality of power amplifiers, and a drive waveform signal generating circuit for supplying a drive waveform signal to the plurality of head units, wherein each of the plurality of head units has a switch device for supplying a piezoelectric element current to the plurality of piezoelectric elements, wherein the plurality of power amplifiers are disposed corresponding to the plurality of head units, the plurality of power amplifiers supplying a drive waveform signal that is input from the drive waveform signal generating circuit to the plurality of power amplifiers so as to drive the plurality of head units.

Abstract: A circuit for driving capacitive loads in a highly efficient manner. In one embodiment, a drive portion is connected to at least one end of a capacitive electric load being applied a voltage waveform. The embodiment further comprises a switching circuit portion having its output connected to the above one end of the capacitive load in order to supply a fraction of the overall current demanded by the load. Additionally, a switching circuit and accompanying switching method provide for efficiently supplying peak current to the capacitive load during voltage fluctuation in the voltage waveform. Briefly, the invention is a circuit arrangement aimed at providing a highly efficient drive for the capacitive load, using a combined linear/switching setup and without distorting the quality of the waveform generated across the capacitive load.

Abstract: A single piezoelectric is excited at a first frequency to cause two vibration modes in a resonator producing a first elliptical motion in a first direction at a selected contacting portion of the resonator that is placed in frictional engagement with a driven element to move the driven element in a first direction. A second frequency excites the same piezoelectric to cause two vibration modes of the resonator producing a second elliptical motion in a second direction at the selected contacting portion to move the driven element in a second direction. The piezoelectric is preloaded in compression by the resonator. Walls of the resonator are stressed past their yield point to maintain the preload. Specially shaped ends on the piezoelectric help preloading. The piezoelectric can send or receive vibratory signals through the driven element to or from sensors to determine the position of the driven element relative to the piezoelectric element or resonator.

Abstract: An integrated circuit (42) provides drive signals to a piezo element (48) of a milli-actuator device (20) in a mass data storage device (10). The integrated circuit (42) includes a circuit (61) for selectively operating the integrated circuit (42) in either a voltage or a charge mode of operation. A first amplifier circuit (44) can be compensated for a variable number of piezo elements in the charge mode of operation by adjustable output impedance adjusting elements (124, 126, 138-141) that are switchably connectable into the amplifier circuit (44).

Abstract: The invention utilizes a multiple frequency ultrasound generator driving a multiple frequency harmonic transducer array to improve cleaning and processing effects while eliminating damage to parts being cleaned. An AC switch and circuitry to modify the output of an ultrasound generator in combination with techniques such as random AM and FM signals are used to produce ultrasound waves that have no single frequency components which eliminates exciting parts being cleaned into resonance.

Abstract: A vibrating gyroscope includes a vibrator having a longitudinal direction and being capable of vibrating in a bending mode in a bending direction perpendicular to the longitudinal direction. The vibrator has first and second nodes which elongate in a direction perpendicular to both the bending direction and the longitudinal direction and first, second, third and fourth supporting members connected to the vibrator such that the first node is interposed between the first and second supporting members and the second node is interposed between the third and fourth supporting members. The first node is located at the vicinity of either the first supporting member or the second supporting member, and the second node is located at the vicinity of either the third supporting member or the fourth supporting member.

Abstract: Method and apparatus for implementing ultrasonic systems that maximize efficiency by dynamically detecting and maintaining peak operational resonance frequency. In one embodiment, the invention dynamically sweeps the output frequency range to locate the peak load current. The resonance frequency corresponding to the peak load current is used as a reference frequency in a control loop. The control loop includes a voltage-controlled oscillator (VCO) that is controlled by a loop controller and operates to lock onto the dynamically sensed reference frequency. In response to the VCO output, a pulse-width modulator (PWM) circuit drives a pair of switches that adjust transducer current to maintain the circuit locked on the resonance frequency at a substantially constant current.

Abstract: A control apparatus for a vibration type actuator improves controllability by providing a control circuit that adjusts a voltage to be applied to the actuator so that a slope of a frequency-speed characteristic of the actuator becomes approximately a constant slope.

Abstract: A control apparatus controls an ultrasonic motor. The ultrasonic motor includes a stator, a piezoelectric element provided in the stator, and a rotor. The rotor is slidably pressed against the stator. When a driving high frequency voltage is applied to the piezoelectric element, the stator is vibrated to rotate the rotor. The control apparatus includes measuring means. The measuring means changes the frequency of a searching high frequency voltage, the searching high frequency voltage being lower than the driving high frequency voltage, thereby measuring a resonance frequency of the ultrasonic motor. The control apparatus drives the motor in a favorable manner.

Abstract: An ultrasonic-motor driving apparatus includes an ultrasonic motor, a driving unit, and a characteristic storage. The driving unit is detachable from the ultrasonic motor and has a driving circuit for driving the ultrasonic motor. The characteristic storage provided in the ultrasonic motor stores driving characteristic values of a resonant frequency and a drive voltage signal specific to the ultrasonic motor. The driving circuit drives and controls the ultrasonic motor based on the driving characteristic values stored in the characteristic storage.

Abstract: An actuator using a piezoelectric element and an operating method thereof. The actuator includes: the piezoelectric element; a drive rod fixed to the piezoelectric element; a moving unit engaging with the drive rod by a frictional force; and a driver for applying a voltage to the piezoelectric element. The voltage repeats a cycle of a first value which is one of a maximum value and a minimum value, a second value which is intermediate between the maximum value and the minimum value, and a third value which is the other of the maximum value and the minimum value so as to drive the driving unit with respect to the drive rod.

Abstract: A high-frequency oscillation circuit incorporates a crystal resonator having a natural oscillation frequency in a high-frequency area within a closed circuit including one or more logic elements. Therefore, this circuit copes with an oscillation frequency of 1 MHz to 2 GHz or more in basic oscillation frequency of a crystal resonator and it oscillates with stability at the basic oscillation frequency of the crystal resonator.

Abstract: A torsion oscillator (FIG. 1) is stabilized in operation by determining the current resonant frequency (62); in a first procedure, observing the oscillator for change in resonant frequency (64), and then restoring the amplitude and median offset (66) without changing the drive frequency. In an alternative procedure, after determining the resonant frequency (62); setting the drive frequency close to but offset from the current resonant frequency (74), observing the oscillator for change in resonant frequency (76), and the restoring the close offset to the changed resonant frequency (78). By operating slightly off peak, the direction of resonant change is immediately known. The first procedure has less difficulties in implementation, but requires more power.

Abstract: The piezoelectric transformer of the present invention has a piezoelectric element 109 mainly formed of a piezoelectric material, primary electrodes 101U and 101D which are formed on the piezoelectric element 109 and to which a voltage is applied, a secondary electrode 102 which is formed on the piezoelectric element 109 and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode 103 which is formed on the piezoelectric element 109 and from which a voltage lower than the output voltage of the secondary electrode is output.

Abstract: A device for transmitting the deflection of an actuator (2), comprising at least one transmission element (4) that has a first, a second and a third support zone, said first support zone (6) being associated with a counter-support, said second support zone (8) being associated with the actuator, and said third support zone being associated with a control element (20). The at least one transmission element rests on the counter-support with the first support zone under the action of the actuator and displaces the control element with the third support zone by way of a rotational movement about a center of rotation. The at least one transmission element is substantially configured as a plate (5) that is disposed substantially perpendicular to the movement of adjustment and the first, the second and the third support zone are configured as substantially plane surfaces on the plate, further relates to a method for producing the inventive transmission element.

Abstract: Piezoelectric elements 10 and 10′ are driven so as to satisfy the relationship Nt=X0(1/(1/k2+1/k3)−1/(1/k1+1/k2+1/k3)) when the drive member, tip 20, and driven member, rotor 40, are in a state of intermittent contact, and in a state near the condition of transition from the intermittent contact state to the normal contact state. When the spring constant of the spring 41 is designated k1, the spring constant of the combined piezoelectric elements 10 and 10′ and the tip 20 is designated k2, the spring constant of the rotor 40 is designated k3, the amount of displacement of the piezoelectric elements 10 and 10′ is designated X0, and the compression force of the spring 41 is designated Nt.

Abstract: A power assistance device for an ultrasonic dental handpiece (5) includes a working circuit with a parallel impedance (Ls) between the output terminals (S1,S2) and a control circuit with a current transformer (T2), the primary winding (7) thereof is serially arranged in the working circuit and the secondary winding (11) thereof forms an RLC circuit in conjunction with a capacitor (13) and a resistor (15) associated therewith. The voltage of the circuit at the terminals of the resistor (15) is transmitted to the input of a power supply (1). The control circuit enables variations in the value of the capacitor (13) and/or the value of the self-inductance coil of the secondary winding (11) of the transformer (T2).

Abstract: A linear motion mechanism comprises a supersonic motor having a rotor which is rotationally driven by vibration of a vibrating body having a piezoelectric element. A transmission mechanism is disposed on the rotor for rotation therewith. A moving body undergoes linear movement in a direction crosswise to a longitudinal axis of a rotational shaft of the rotor in accordance with rotation of the transmission mechanism. A pressurizing mechanism presses the moving body into pressure contact with the transmission mechanism.

Abstract: A micromotor comprising: a piezoelectric element including a common electrode and a plurality of other electrodes formed thereon and including at least a first a and a second electrode group, each group including at least one electrode, wherein the piezoelectric element causes motion in a first direction when a voltage is applied between the first electrode group and the common electrode, and wherein the piezoelectric element causes motion in a second direction when a voltage is applied between the second electrode group and the common electrode; a voltage source that electrifies the common electrode; and at least two switches separately connected between the first and second electrode groups and a low voltage, said switches being activatable to connect one of said first and second electrode groups to the low voltage to cause selective motion in the first or second directions.

Abstract: The piezoelectric transformer of the present invention has a piezoelectric element 109 mainly formed of a piezoelectric material, primary electrodes 101U and 101D which are formed on the piezoelectric element 109 and to which a voltage is applied, a secondary electrode 102 which is formed on the piezoelectric element 109 and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode 103 which is formed on the piezoelectric element 109 and from which a voltage lower than the output voltage of the secondary electrode is output.

Abstract: A smooth impact drive mechanism utilizing an electromechanical conversion element, in which a preheating voltage to preheat the electromechanical conversion element is impressed thereto before the impression of a drive voltage to the electromechanical conversion element, in order to realize stable drive characteristics by reducing fluctuation in the speed of the moving unit. In addition, drive parameters are changed in accordance with the temperature of the electromechanical conversion element. Furthermore, drive parameters are changed in accordance with the moving speed of the moving unit.

Abstract: A driving apparatus of a vibration type actuator includes an apparatus for forming a vibration wave by applying four-phase AC signals having temporal phase differences to four-phase driving phases arranged at intervals of ¼ wavelength, which includes first and second transformers and two-phase driving phases connected to the secondary terminals of the respective transformers, thereby simplifying the arrangement of a driving circuit.

Abstract: The present invention is a power conditioning circuit. The invention is comprised of multiple comparators and a bilateral switch. The invention converts the high-frequency, high-voltage output signal from a piezoelectric transformer to a desired low-frequency voltage signal, examples including but not limited to sinusoidal, sawtooth, ramp, and square waves, at the output amplitude voltage. The circuit switches the high-frequency AC output, also referred to as the driving waveform, into the load at precisely the instant when the driving waveform crosses the present voltage load value, and switches it out when the load waveform reaches the desired voltage. Thereafter, the switch is opened and the reactance of the load or an additional output capacitor element holds the voltage until the next switching cycle.

Abstract: An identification device having a piezoelectric sensor array is used to obtain biometric data. Multiplexers are switched to control the sensor. The device has several operating modes for obtaining a variety of biometric data, including an impedance detection mode, a voltage detection mode, an imaging mode, and a Doppler-shift detection mode. The presence of a fingerprint on the sensor can be used to turn-on the device. The device is capable of capturing a fingerprint, forming a three-dimensional map of a finger bone, and/or determining the direction and speed of arteriole and/or capillary blood flow in a finger. A single pixel or a group of pixels can be detected and readout to a memory. The device can be used as an electronic signature device. The device can operate as part of a personal area network, using a public service layer according to the invention.