The invention relates to a phaco driver system for controlling operation of an ophthalmic surgical phacoemulsification device. The phaco driver system comprises a resonant output circuit for generating a transducer voltage for driving an ultrasonic transducer of the ophthalmic surgical phacoemulsification device. Further, the phaco driver system includes a bridge unit for generating a bridge output signal for feeding the resonant output circuit, the bridge output signal being based on a composition of the first and second phase signals having a fixed mutual phase difference.

A controller for a haptic actuator is described. The controller includes a driver which has an output configured to be coupled to a linear resonant actuator in a first mode and a frequency detector having an input configured to be coupled to the haptic actuator in a second mode. The frequency detector is configured to detect a signal generated on the terminals of the haptic actuator in response to an externally applied force and to determine a resonant frequency of the haptic actuator from the generated signal.

An electric measurement circuit possesses an electrical reaction leg for forming an oscillator from a resonator, and furthermore possesses a measurement leg the input of which is supplied by the electrical reaction leg. The measurement leg contains an adjustable phase shifter so that an additional excitation force that is applied to the resonator in the measurement leg can be adjusted in phase quadrature with respect to an excitation force that is applied to the resonator in the electrical reaction leg. Such an electrical measurement circuit is particularly suitable for forming a photoacoustic gas detector.

A method for minimizing settling of a moving mass of an electromagnetic load may include determining a polarity and a magnitude of a velocity of the moving mass based on real time measurements of one or more parameters associated with the electromagnetic load and based on the polarity and the magnitude of the velocity, generating a braking signal to be applied to the moving mass that opposes the polarity of the velocity.

Embodiments described herein relate to methods and apparatuses for controlling an operation of a vibrational output system and/or an operation of an input sensor system, wherein the controller is for use in a device comprising the vibrational output system and the input sensor system. A controller comprises an input configured to receive an indication of activation or de-activation of an output of the vibrational output system; and an adjustment module configured to adjust the operation of the vibrational output system and/or the operation of the input sensor system based on the indication to reduce an interference expected to be caused by the output of the vibrational output system on the input sensory system.

A vibration device is provided that includes a vibration element with a piezoelectric vibrator and a driving device that causes the vibration element to vibrate. The vibration element includes a translucent body and the piezoelectric vibrator is electrically coupled to the driving device. The driving device includes a first circuit that applies an electric signal to the piezoelectric vibrator to render the vibration element in a resonant state, a second circuit that applies an electric signal to the piezoelectric vibrator according to a feedback signal output from the piezoelectric vibrator, and a switch that switches coupling between the first circuit and the piezoelectric vibrator and coupling between the second circuit and the piezoelectric vibrator at a certain timing.

A capacitive vibrating-membrane ultrasonic transducer includes a carrier with a cavity, a vibrating membrane fastened to the carrier and covering the cavity, and a conductive element separated from the membrane by the cavity. The vibrating membrane has a resonant frequency in membrane mode fm and a resonant frequency in plate mode fp according to the relationship fm>fp. An exciting circuit has terminals connected to the vibrating membrane and the conductive element, and is configured to apply, across its terminals, an electrical signal the maximum frequency fo according to the relationship fm>1.5*fo; or a measuring circuit is connected to the vibrating membrane and the conductive element and configured to measure capacitance variations up to a frequency fo.

An acoustophoretic system is controlled and driven to attain a desired level of performance. An RF controller and a driver provide a frequency and power to an acoustic transducer, which can be implemented as a piezoelectric element, which presents a reactive load or a complex load. A controller implements a control technique for efficient transducer operation. The control technique can locate a frequency for operation that is at a reactance minimum or maximum for the system to produce a modal pattern and to provide efficient operation of the transducer. A method of detecting a minimum or maximum reactance in a acoustophoretic system used to trap, separate, deflect, cluster, fractionate or otherwise process particles or secondary fluids or tertiary fluids in a primary fluid and utilizing the frequency of the detected reactance to operate the acoustophoretic system.

Embodiments described herein relate to methods and apparatus for driving a haptic transducer with a driving signal. The method comprises estimating, based on a current through the haptic transducer and a terminal voltage across the haptic transducer, a back electromotive force, EMF, voltage representative of a velocity of a mass in the haptic transducer; comparing a phase of a voltage signal derived from the terminal voltage with a phase of the estimated back EMF voltage; and based on the comparison, adjusting a frequency or a phase of an output signal, wherein the driving signal is derived from the output signal, such that a frequency of the driving signal converges to a resonant frequency of the haptic transducer.

A resonant frequency tracker for driving an electromagnetic load with a driving signal may include a signal generator configured to generate a waveform signal at a driving frequency for driving an electromagnetic load and control circuitry. The control circuitry may be configured to, during driving of the electromagnetic load by the waveform signal or a signal derived therefrom, receive a current signal representative of a current associated with the electromagnetic load and a second signal representative of a second quantity associated with the electromagnetic load, the second quantity comprising one of a voltage associated with the electromagnetic load or a back electromotive force of the electromagnetic load. The control circuitry may be further configured to calculate a phase difference between the current signal and the second signal, determine a frequency error of the waveform signal based on the phase difference, and control the driving frequency based on the frequency error.