Abstract: A driving circuit for driving a piezoelectric load, can include: an energy-storage capacitor; a first power stage circuit configured to convert an input voltage into a first voltage, and to store the first voltage in the energy-storage capacitor; a second power stage circuit configured to receive the first voltage to charge the piezoelectric load during a first operation interval of an operation period, such that a power supply voltage signal provided to the piezoelectric load in the first operation interval corresponds to a reference voltage in a first interval; and a discharging circuit configured to discharge the piezoelectric load during a second operation interval of the operation period, such that the power supply voltage signal in the second operation interval corresponds to the reference voltage in a second interval.

Abstract: A device includes a readout circuit coupled between an input node and an output node; a microelectromechanical systems (MEMS) device coupled to the input node; and a first charge controlled clamp circuit coupled between the input node and a first bias node.

Abstract: The driving device includes a piezoelectric element, a power supply unit, a first resistor, a second resistor, a measuring unit and a control unit, wherein resistance values of the first resistor and the second resistor are smaller than an insulating resistance value of the piezoelectric element, the measuring unit measures, a voltage across the first resistor (voltage between a first terminal and a second terminal), in a state of supplying a predetermined voltage from the power supply unit, and the control unit calculates a resistance value of the piezoelectric element from a voltage value obtained by the measurement of the measuring unit, and determines, whether or not degradation has occurred in the piezoelectric element based on the calculated resistance value.

Abstract: Various embodiments include a method for actuating a piezo actuator of an injection valve of a fuel injection system comprising: determining actuation signals for the piezo actuator using a stored current/voltage characteristic curve for carrying out an injection process; detecting the profile of the current flowing through the piezo actuator during the injection process and the profile of the voltage applied to the piezo actuator during the injection process; adapting the stored current/voltage characteristic curve based at least in part on the detected current profile and the detected voltage profile; and determining actuation signals for the piezo actuator using the stored, adapted current/voltage characteristic curve for carrying out a subsequent injection process.

Abstract: A piezoelectric actuator control device comprising a first voltage converter supplying a DC voltage on a DC power supply bus to which is connected a second voltage converter capable of generating a variable excitation voltage under the control of a control computer, the second voltage converter comprising two switch half-bridges mounted in parallel with the terminals of a bus capacitor, the control computer being suitable for controlling the two switch half-bridges according to a first control configuration, in which they are controlled independently in order to each supply a voltage in a range between zero and a maximum positive value and according to a second control configuration, in which they are jointly controlled as a full-bridge for supplying a voltage between a minimum negative value and said maximum positive value.

Abstract: In a piezoelectric ejector assembly, a piezoelectric actuator is attached to an ejector mechanism, while a drive signal generator and a controller are coupled to the actuator. The drive signal generator is configured to generate a drive signal for driving the actuator to oscillate the ejector assembly. The controller is configured to control the drive signal generator to drive the actuator at a resonant frequency of the ejector assembly, and an auto-tuning circuit is provided to define the optimum drive signal frequency.

Abstract: An actuator device (21) comprises an electroactive polymer (EAP) and a driver (20) for generating a electrical drive signals which give opposite polarity voltages and thus electrical field within the electroactive polymer at different times. In this way, charge build-up can be reduced or avoided, while prolonged activation times are still possible. This improves the performance and/or lifetime of the device.

Abstract: A nebulizer includes an aerosolizer, a controller, a power converter, a power source and a voltage detector. When the aerosolizer is requested to eject aerosolized liquid at a standard spraying speed, the controller sets a parameter value of a conversion parameter based on a stored standard value, transmits the parameter value to the power converter, and controls the power source to supply electric power. The power converter converts the electric power based on the parameter value to power the aerosolizer. Based on a stored expected value and a detected value generated by the voltage detector in response to operation of the aerosolizer, the controller controls the power source to adjust the voltage of the electric power supplied thereby.

Abstract: The invention refers to an apparatus for driving a load with a drive signal. The apparatus includes an AC voltage source, a DC voltage source, a capacitor and a control apparatus. The AC voltage source outputs an AC voltage. The DC voltage source outputs a DC voltage. The capacitor includes a first terminal and a second terminal. The AC voltage source is connected to the first terminal, and a signal output is connected to the second output. The control apparatus controls, depending on a voltage present at the signal output, a connection between the DC voltage source and the second terminal. Furthermore, the invention refers to a corresponding method as well as to a device.

Abstract: Method including a plurality of EAP based sections, a power source/sink unit and a controller. Each EAP based section includes an electronic charge/discharge unit and variable capacitor having an elastically deformable body with an arrangement of stretchable synthetic material and electrodes functioning as the capacitor with a variable capacitance as the deformable body stretches and relaxes. Each EAP based section is connected to the power source/sink unit by the respective electronic charge/discharge unit under control of the controller which includes: a processing unit coupled to a sensing circuitry which is coupled to the variable capacitor of each EAP based section, and a driving circuitry coupled to the electronic charge/discharge unit.

Abstract: A method for operating a circuit for charging and discharging a capacitive actuator. The circuit has a series circuit of first and second power transistors with respective parallel-connected diodes connected between the potentials of a supply voltage source. The node between the power transistors is connected via a coil to the capacitive actuator. For charging the actuator, the first power transistor, which connects the capacitive actuator to the positive potential, is periodically turned on during a prescribed time and turned off when a first prescribed threshold value is reached by the current through the actuator, until a lower threshold value is reached by the current. If the actuator current no longer reaches the first prescribed threshold value then the first power transistor is turned off after a time that corresponds to the maximum value reached by the actuator current.

Abstract: Embodiments of the present invention relate to ultrasound (acoustic) data transmission systems, in particular data transmission over wide-band acoustic channels with frequency-dependant multi-path propagation. More specifically, embodiments of the invention involve increasing the bit rate in the acoustic channel by means of utilization of the entire ultrasound spectrum available for data transmission inside a human body.

Abstract: A machine learning apparatus that learns predicted life of a power device of a motor driving apparatus converting DC power into AC power by a switching operation of the power device to supply the AC power to an AC motor includes: a state observation unit that observes a state variable constituted by data regarding the number of times of switching of the power device, data regarding junction temperature of the power device, and data regarding presence or absence of a failure of the power device; and a learning unit that learns the predicted life of the power device in accordance with a training data set defined by the state variable.

Abstract: Methods and systems for applying charge to a piezoelectric element include and/or facilitate implementation of processes including cyclical multi-stage processes for: providing a piezoelectric element with an accumulated charge; providing one or more charge holding elements with a scavenged charge from the piezoelectric element; substantially removing or discharging a remaining charge from the piezoelectric element; and applying the scavenged charge to the piezoelectric element with an opposite polarity in relation to the polarity of the remaining charge.

Abstract: A capacitive actuator is connected to an output of an apparatus which is formed with a capacitor connected between an input and a reference potential, with a full bridge with four power switching elements connected in parallel with the capacitor. To charge the capacitive actuator, a control circuit first turns on the first and third power switching elements. Current then flows from the first capacitor via a coil connected between the bridge paths and energy is stored in the coil. When a maximum current value is reached, the first and third power switching elements are switched off and magnetic energy stored in the coil decays due to current flow via the diodes of the second and fourth power switching elements. This charges the capacitive actuator. The capacitive actuator is charged to a predefined voltage by possible repeated switching of the first and third power switching elements.

Abstract: A method for controlling an inertial drive on the basis of pulse trains is disclosed. The pulse trains include pulses having sections of different gradients and having variable amplitude and/or frequency. A pulse interval occurs between the individual pulses, wherein the selected pulse duration is so short that is substantially less than the cycle duration of the natural oscillation of the system to be driven.

Abstract: A fuel control system according to the principles of the present disclosure includes a voltage measuring module, a first difference module, a second difference module, a third difference module, and an injector driver module. The voltage measuring module measures first and second voltages at first and second electrical connectors of a fuel injector of an engine. The first difference module determines a first difference based on a difference between the first and second voltages. The second difference module determines a second difference between (i) the first difference and (ii) a previous value of the first difference. The third difference module determines a third difference between (i) the second difference and (ii) a previous value of the second difference. The injector driver module selectively applies power to the fuel injector based on the third difference.

Abstract: A method for monitoring the condition of a piezoinjector of a fuel injection system is disclosed. The fuel injection is carried out in injection cycles, each of which comprises a filling phase, a holding phase, and an emptying phase. The discharge resistance is ascertained during the holding phase of the piezoinjector. Conclusions about the working order of the piezoinjector are drawn using the ascertained discharge resistance.

Abstract: A system and method described herein detects the presence of an unconnected condition in high voltage component cables in an electric or hybrid-electric vehicle having a high voltage battery or energy storage system. The system includes a DC-DC converter which is capable of operating in either a step-down mode (e.g., as a buck converter) or a boost mode. The system uses the DC-DC converter operating in boost mode to create a sufficient, yet safe, measuring voltage on the main high voltage cabling of the vehicle before allowing the energy storage system to begin supplying high voltage power to the system components. The measurements are taken at various points near the individual components to determine if the cable has become disconnected.

Abstract: In a piezoelectric ejector assembly, a piezoelectric actuator is attached to an ejector mechanism, while a drive signal generator and a controller are coupled to the actuator. The drive signal generator is configured to generate a drive signal for driving the actuator to oscillate the ejector assembly. The controller is configured to control the drive signal generator to drive the actuator at a resonant frequency of the ejector assembly, and an auto-tuning circuit is provided to define the optimum drive signal frequency.

Abstract: A printhead provides actuation pulses for driving actuating elements from a common drive waveform via respective switching circuits, the waveform having a pre-charge ramp followed by a steeper slope. A start voltage of a leading edge of the actuation pulse is set by opening the switching circuit to decouple the common drive waveform from its actuating element part way along the pre-charge ramp. After the pre-charge ramp the actuating element is coupled again to the common drive waveform, so that the voltage across the actuating element follows the steeper slope to form the leading edge. Adjusting the timing of the decoupling adjusts the start voltage, enables trimming relative to other actuating elements. The gentle slope of the pre-charge ramp enables the precision of timing of switching to be more relaxed, so that trigger circuitry for controlling the switching circuit can be simpler, smaller, cheaper and thermally more efficient.

Abstract: A piezoelectric driving circuit and a driving method thereof are provided. The piezoelectric driving circuit drives a piezoelectric circuit by using a first driving switch connected to one end of a piezoelectric circuit, a second driving switch corresponding to the first driving switch and connected to the other end of the piezoelectric circuit, and a sensing resistor for sensing a current flowing in the piezoelectric circuit. A fire angle and a duty cycle of an upper switch are adjusted such that a peak of a sense voltage generated in the sensing resistor at a timing at which the first driving switch is turned on, in a state in which the second driving switch is turned on.

Abstract: A method for regenerative driving of one or more transducers includes, for each of a plurality of driving cycles, enabling a number of transducers for driving, configuring a configurable capacitive energy storage element based on the number of enabled transducers and a desired overall capacitance, transferring a predetermined quantity of energy from a power supply to a first inductive energy transfer element, distributing the predetermined quantity of energy from the first inductive energy transfer element to the configurable capacitive energy storage element and to one or more other capacitive energy storage elements, each of the other capacitive energy storage elements coupled to an associated transducer, transferring energy from the one or more capacitive energy storage elements and from the configurable capacitive energy storage element to a second inductive energy transfer element, and transferring energy from the second inductive energy transfer element to the power supply.

Abstract: Methods and systems for applying charge to a piezoelectric element include and/or facilitate implementation of processes including cyclical multi-stage processes for: providing a piezoelectric element with an accumulated charge; providing one or more charge holding elements with a scavenged charge from the piezoelectric element; substantially removing or discharging a remaining charge from the piezoelectric element; and applying the scavenged charge to the piezoelectric element with an opposite polarity in relation to the polarity of the remaining charge.

Abstract: In the case of a multi-voltage on-board power supply system for a motor vehicle having a hybrid or electric drive, comprising a dc-dc converter, by means of which a high voltage level having a higher direct-current voltage and at least a first energy storage device is connected to a low voltage level having a lower voltage and at least a second energy storage device, wherein the system comprises a charging interface for charging external devices, at least one converter phase of the dc-dc converter can be disconnected from the low voltage level and instead can be connected with the charging interface, and a third energy storage device can be connected to the charging interface in order to supply the third energy storage device with a lower voltage and permit a charging of the third energy storage device by the energy flow from the first energy storage device.

Abstract: Embodiments of the present invention relate to ultrasound (acoustic) data transmission systems, in particular data transmission over wide-band acoustic channels with frequency-dependant multi-path propagation. More specifically, embodiments of the invention involve increasing the bit rate in the acoustic channel by means of utilization of the entire ultrasound spectrum available for data transmission inside a human body.

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 capacitive load drive circuit includes first and second capacitive loads, first and second connection path selection sections, and a voltage generation section. The first capacitive load and the second capacitive load are configured to charge and discharge in accordance with a drive signal. The first connection path selection section is configured to selectively supply a plurality of voltages to the first capacitive load, the first connection path selection section being arranged so as to correspond to the first capacitive load. The second connection path selection section is configured to selectively supply a plurality of voltages to the second capacitive load. The second connection path selection section is arranged so as to correspond to the second capacitive load. The voltage generation section is configured to generate and supply the voltages shared by the first connection path selection section and the second connection path selection section.

Abstract: A switching apparatus comprising a contact point section including a first contact point; an actuator including a first piezoelectric film that expands and contracts according to a first drive voltage and a second piezoelectric film provided in parallel with the first piezoelectric film and expands and contracts according to a second drive voltage, and a control section that controls the first drive voltage and the second drive voltage is provided. The actuator moves a second contact point to contact or move away from the first contact point according to the contraction and expansion of the first piezoelectric film and the second piezoelectric film. When switching from a contact state to a separated state, the control section stops supplying the first drive voltage and applies the second drive voltage causing the second piezoelectric film to contract to the second piezoelectric film, such that the actuator is biased to return.

Abstract: A device includes a drive portion for driving a pressure generating element and controlling a state of driving the element. The drive portion includes a first drive section for causing a first current to flow to drive the element, and a second drive section for causing a second current smaller than the first current to flow to drive the element. The state of driving the element includes a first state and a second state. The second drive section causes the second current to flow in a direction in which the element is switched from the first state to the second state at a timing that is faster by a predetermined time determined in advance with respect to a timing at which the first drive section causes the first current to flow for switching the state of driving the element from the first state to the second state.

Abstract: A device for charging and discharging a capacitive actuator connectable to an output connection has a first capacitor disposed between an input connection and a reference potential. The device has a series connection composed of a first and a second power switching element which is connected in parallel with the first capacitor. The device additionally has a first coil with a first connection connected to the center tap of the series connection, wherein the second connection of the first coil is connected to the reference potential via a third power switching element and to the output connection via a fourth power switching element. Wherein the power switching elements have diodes connected in parallel therewith such that they are reverse-biased from the input connection or the output connection to the reference potential. Wherein a connection of the fourth power switching element is connected to the input connection via a diode.

Abstract: A method for operating an output stage for a piezoactuator includes checking, during an operating phase, in response to the undershooting of a current for the piezoactuator below a setpoint current, whether a point in time for the undershooting lies outside or within a time window. A subsequent current pulse is controlled via the setpoint current if the point in time is located outside the time window, and the subsequent current pulse is controlled via a turn-on time if the point in time is located within the time window.

Abstract: An ultrasonic transducer driving circuit configured to supply an output current and/or an output voltage to an output line for driving an ultrasonic transducer is provided. The ultrasonic transducer driving circuit includes a first current discharge circuit configured to allow a current arising from electric charges accumulated in the ultrasonic transducer to flow from the output line to ground when the output line is at a positive voltage, and a second current discharge circuit configured to allow the current arising from the electric charges accumulated in the ultrasonic transducer to flow from ground to the output line when the output line is at a negative voltage. The first current discharge circuit and the second current discharge circuit are controlled based on the output current and/or the output voltage.

Abstract: The disclosed invention provides a device for driving a piezoelectric element, making it possible to make an output voltage follow a control voltage during a discharging action. A charging circuit charges a piezo element through a first node. A discharging circuit discharges electric charge charged in the piezo element through the first node. A control circuit makes switching to cause the discharging circuit to perform a discharging action or cause the charging circuit to perform a charging action, based on a comparison between the magnitude of a voltage being applied to the piezo element and the magnitude of a control voltage.

Abstract: The present invention generally relates to medical systems and apparatus and uses thereof for treating obesity and/or obesity-related diseases, and more specifically, relates to systems and methods for energy recovery in a laparoscopically-placed gastric banding system operably coupled to a piezo actuator. The energy recovery may be obtained utilizing an energy recovery device, such as an inductor, coupled to the piezo actuator. The energy recovery device may utilize two circuits to facilitate energy recovery, and the two circuits may include diodes with opposite orientations to control current flow.

Abstract: A pressure control valve piezoelectric element driving circuit is provided for a pressure type flow rate control device provided with a flow rate self-diagnosis function for comparing initial pressure drop characteristics data measured and with pressure drop characteristics data in a flow rate diagnosis which are measured under conditions that are the same for both measurements to detect malfunction in flow rate control from a difference between both characteristics data, wherein a first discharge circuit slowly discharges a piezoelectric element driving voltage applied to the piezoelectric element according to a step-down command signal from a CPU, through a step-down command circuit to step down the voltage, and a second discharge circuit that rapidly discharges a piezoelectric element driving voltage applied to the piezoelectric element according to a high-speed step-down command signal from the CPU, through a high-speed step-down command circuit to step down the voltage.

Abstract: A discharge energy recovery device to recover discharge energy discharged from a piezoelectric element when the piezoelectric element is driven includes a drive voltage generator to generate a voltage to drive the piezoelectric element; a discharge voltage monitoring unit to monitor a voltage discharged from the piezoelectric element when the piezoelectric element is driven; a first current supplier to supply a current energy to operate a first load circuit when the discharged voltage is equal to or greater than a first voltage that enables driving of the first load circuit, and a second current supplier to supply a current energy to operate a second load circuit when the discharged voltage is less than the first voltage and equal to or greater than a second voltage that enables driving of the second load circuit by monitoring the currently discharged voltage using the discharge voltage monitoring unit.

Abstract: A single element of an ultrasonic transducer includes at least one combination of an equivalent series capacitor C1, an equivalent series inductor L1, and an equivalent series resistance R1. The ultrasonic transducer further includes an equivalent parallel capacitor C0. An inductor L2 is connected in series between the ultrasonic transducer and the drive circuit. A first resonance frequency of the equivalent series capacitor C1 and the equivalent series inductor L1 is F0. A second resonance frequency determined by at least the equivalent parallel capacitor C0 and the inductor L2 is Fp. A drive circuit drives the ultrasonic transducer while switching the driving frequency of the ultrasonic transducer to one of the resonance frequency F0 and the resonance frequency Fp.

Abstract: An electric circuit for triggering a piezoelectric element, in particular of a fuel injection system of a motor vehicle. Two transistors connected in series and triggerable using a clock pulse are provided, whose shared connecting point is coupled to the piezoelectric element and one of which is provided for discharging the piezoelectric element. In the event of an error, the transistor provided for discharging can be triggered using the clock pulse.

Abstract: A method and device for charging and/or discharging a capacitive element. A controllable switch is driven to interrupt the charging current when the charging current exceeds a predetermined charging-current threshold. The charging-current threshold is altered while the capacitive element is being charged to the predefined charging voltage. The controllable switch is driven again for coupling the charging current into the capacitive element if a predefined period of time after a previous activation of the controllable switch has elapsed, and/or in case the charging current drops below the predetermined charging-current threshold. A discharging process is carried out correspondingly.

Abstract: A control device for suppression of residual vibration of a piezoelectric transducer includes a capacitive energy storage component, and a switch unit. The control device is operable in a non-working mode, in which the switch unit provides voltage on the capacitive energy storage component to the piezoelectric transducer for reducing the residual vibration of the piezoelectric transducer. The capacitive energy storage component has a capacitance value that is sufficient for enabling the voltage on the capacitive energy storage component to substantially track voltage on the piezoelectric transducer under the non-working mode.

Abstract: One embodiment of the present invention features a circuit for driving a piezoelectric actuator, comprising a first transmission line to provide an input signal having a time-varying voltage; a second transmission line to provide a predetermined voltage current; a piezoelectric element; and a switch coupled to the second transmission line and the piezoelectric element, the switch configured to electrically connect and disconnect the predetermined voltage current to and from the piezoelectric element based on the input signal.

Abstract: The generator for a piezoelectric transducer, in particular for a piezoelectric motor for medical or dental applications, comprising two transformers (11A, 11B) each including a primary winding (L1) and a secondary winding (L2), and four switches (19A, 19B, 21A, 21B) driven by an ultrasonic frequency oscillator, two of said four switches (21A, 21B) being designed to connect alternately the secondary of each transformer to the piezoelectric load (5), and the two other switches (19A, 19B) being designed to connect alternately the two primary windings to a power supply (17) so that during a first half cycle, called “the positive half cycle” the primary winding of one of said two transformers is charged with power, while the secondary winding of the other transformer discharges power to the piezoelectric load, and so that during a second half cycle, called “the negative half cycle” the secondary winding of said one transformer discharges power to the piezoelectric load, while the primary winding of the other tran

Abstract: A discharge energy recovery device to recover discharge energy discharged from a piezoelectric element when the piezoelectric element is driven includes a drive voltage generator to generate a voltage to drive the piezoelectric element; a discharge voltage monitoring unit to monitor a voltage discharged from the piezoelectric element when the piezoelectric element is driven; a first current supplier to supply a current energy to operate a first load circuit when the discharged voltage is equal to or greater than a first voltage that enables driving of the first load circuit, and a second current supplier to supply a current energy to operate a second load circuit when the discharged voltage is less than the first voltage and equal to or greater than a second voltage that enables driving of the second load circuit by monitoring the currently discharged voltage using the discharge voltage monitoring unit.

Abstract: A discharge energy recovery device to recover discharge energy discharged from a piezoelectric element when the piezoelectric element is driven includes a drive voltage generator to generate a voltage to drive the piezoelectric element; a discharge voltage monitoring unit to monitor a discharge voltage discharged from the piezoelectric element when the piezoelectric element is driven by the drive voltage generator; a plurality of charge accumulating devices to accumulate a charge corresponding to a voltage monitored by the discharged voltage discharge voltage monitoring unit; and a selection unit to select one or more charge accumulating devices from the plurality of charge accumulating devices having capacity sufficient to enable accumulation of the charge corresponding to the voltage monitored by the discharge voltage monitoring unit.

Abstract: A method for operating an output stage for a piezoactuator includes checking, during an operating phase, in response to the undershooting of a current for the piezoactuator below a setpoint current, whether a point in time for the undershooting lies outside or within a time window. A subsequent current pulse is controlled via the setpoint current if the point in time is located outside the time window, and the subsequent current pulse is controlled via a turn-on time if the point in time is located within the time window.

Abstract: A driver, including: a piezoelectric element extending and contracting upon application of an electrical voltage; a driving member having one end secured to the piezoelectric element; a frictionally coupling member, frictionally coupling the driving member; and a drive circuit, connected with a power supply to activate the piezoelectric element at a predetermined period, including: a charge switching element for connecting an electrode of the piezoelectric element with the power supply, a discharge switching element, and a protective resistor arranged in an electric path between the power supply and the piezoelectric element or between the piezoelectric element and a ground point, wherein a resistance value of the protective resistor is set larger than an ON resistance of the switching element but smaller than a value obtained by dividing one half of the drive period of the switching element by a capacitance of the piezoelectric element, in a predetermined period.

Abstract: A device for driving ultrasound piezoelectric actuators, on the basis of a DC voltage. The device includes an impedance matching branch mounted in parallel with the actuators and including a capacitor in series with a selection switch, which is closed and opened, at the same time as the selection switch of the actuator to be excited, so that the voltage across the terminals of the matching capacitor and the voltage across the terminals of the selected actuator are almost zero before the start and after the end of the injection. A method of controlling the matching switch makes it possible to benefit from the capacitive charge during the pulse train causing the injection, while circumventing abrupt discharges at the start of the train. Such a device and method may find application to the engines of motor vehicles, as one example.

Abstract: A nanoelectromechanical systems (NEMS) device and method for using the device provide for a movable member that includes a region of low conductivity over which an electric field is developed. A region width is within a factor of ten (10) of a thickness of the NEMS device. The region is formed between a junction that incorporates piezoelectric material. A first voltage is applied across the region which alters a width of an active portion of the region thereby adjusting a movement of the movable member induced by a second voltage. The second voltage is applied across the region to produce a strain on the active portion of the region. The strain results in a defined movement of the movable member.

Abstract: A method for controlling the displacement of a stack of a piezoelectric actuator for use in a fuel injector comprises determining a desired amount of charge (?Q) to be added or removed from the stack. The method further comprises determining an operating parameter of the fuel system and selecting a drive current level (PO, SO) and a drive time (topen, tclose) in accordance with the desired amount of charge (?Q) and the operating parameter, and driving the drive current through the stack for the drive time (topen, tclose) in order to add or remove the desired amount of charge (?Q).