A multi-channel drive system for a piezoelectric actuator having a multiple-frequency resonant mode, the system including multiple signal generators, multiple feedback circuitries, and a processor. The multiple signal generators are configured to generate multiple respective drive signals at multiple respective drive signal frequencies, and to drive the piezoelectric actuator with the multiple drive signals. The multiple feedback circuitries are configured to measure multiple respective feedback signals at the multiple drive signal frequencies. The processor is configured to adaptively maintain the piezoelectric actuator vibrating in the multiple-frequency resonant mode, by adjusting the drive signal frequencies in response to the respective measured feedback signals.

Transducer driving methods and transducer driving systems are described. According to one aspect, a transducer driving method includes providing a plurality of initial driving signals to a transducer, wherein each of the initial driving signals has a respective one of a plurality of different frequencies, identifying one of the frequencies where the transducer has a reduced impedance as a result of the provision of one of the initial driving signals having the one frequency to the transducer compared with impedances of the transducer resulting from the provision of others of the initial driving signals having others of the frequencies to the transducer, determining that the identified one of the frequencies is not acceptable for driving the transducer, as a result of the determining, identifying another of the frequencies, and driving the transducer using another driving signal having the another frequency.

A nebulizer has an aperture plate, a mounting, an actuator, and an aperture plate drive circuit (2-4). A controller measures an electrical drive parameter at each of a plurality of measuring points, each measuring point having a drive frequency; and based on the values of the parameter at the measuring points makes a determination of optimum drive frequency and also an end-of-dose prediction. The controller performs a short scan at regular sub-second intervals at which drive current is measured at two measuring points with different drive frequencies. According to drive parameter measurements at these points the controller determines if a full scan sweeping across a larger number of measuring points should be performed. The full scan provides the optimum drive frequency for the device and also an end of dose indication.

According to embodiments described herein, there are provided methods and apparatus for providing a driving signal to a transducer, wherein the driving signal is output by an amplifier. A method comprises receiving an indication of a voltage and a current of the driving signal; based on an electrical model of the transducer and the voltage and the current of the driving signal, estimating an estimated electrical response of the transducer representative of movement of a mass in the transducer; comparing the estimated electrical response to a desired electrical response; and controlling the driving signal based on the comparison.

An ultrasonic probe including: a plurality of transducers; a plurality of low-noise amplifier circuits individually corresponding to the plurality of transducers, the plurality of low-noise amplifier circuits having a variable resistor feedback unit making a resistance value variable by an electrical signal inputted to a control terminal; and a control circuit; wherein the control circuit has a dummy circuit generating a bias voltage of a feedback unit of the low-noise amplifier circuit, and an adding circuit outputting an added signal of a bias voltage by the dummy circuit and a control signal increasing or decreasing with a lapse of time; and the plurality of low-noise amplifier circuits input an output of the adding circuit to the control terminal of the variable resistor feedback unit to perform variable control on a gain of the low-noise amplifier circuit.

The present invention relates to a haptic feedback system and, particularly, to a device and a method for controlling an actuator for haptic feedback, the method comprising: a first step of controlling the output of an oscillator such that a clock necessary in the generation of a driving signal for driving an actuator is oscillated at a reference clock frequency; a second step of calculating the resonance frequency of the actuator from a cycle of a BEMF signal according to the driving of the actuator; and a third step of calculating a clock frequency for following the calculated resonance frequency of the actuator so as to newly change and set same to the reference clock frequency, thereby controlling the output of the oscillator.

A nebulizer has an aperture plate, a mounting, an actuator, and an aperture plate drive circuit (2-4). A controller measures an electrical drive parameter at each of a plurality of measuring points, each measuring point having a drive frequency; and based on the values of the parameter at the measuring points makes a determination of optimum drive frequency and also an end-of-dose prediction. The controller performs a short scan at regular sub-second intervals at which drive current is measured at two measuring points with different drive frequencies. According to drive parameter measurements at these points the controller determines if a full scan sweeping across a larger number of measuring points should be performed. The full scan provides the optimum drive frequency for the device and also an end of dose indication.

A vibration actuator and a method for driving the vibration actuator can improve the user's tactile sensation. A plurality of tactile devices are attachable at different positions on a surface of a touch panel to vibrate the touch panel. A driver drives, in response to a touch detection signal representing a touch position from the touch panel, the plurality of tactile devices each using a driving signal having a predetermined driving frequency. Of the plurality of tactile devices, a tactile device closest to the touch position is operable as a master device, and a tactile device other than the master device is operable as a slave device. The master device and the slave device are driven using the driving signal having the driving frequency being a resonant frequency of the master device.

A digital processor of a nebulizer controller controls and monitors drive current (I) applied to an aperture plate. The drive current is detected as a series of discrete values at each of multiple measuring points, each having a particular drive frequency The processor in real time calculates a slope or rate of change of drive current with frequency and additionally determines a minimum value for drive current leading up to the peak value. The processor uses both the value of the minimum drive current during the scan and also the maximum slope value to achieve reliable prediction of end of dose, when the aperture plate becomes dry.

The present invention relates to a haptic feedback system and, specifically, to a device and method for controlling an actuator for haptic feedback, the method comprising: an actuator resonance frequency correction driving step of driving an actuator by repeatedly generating and outputting a drive signal including a driving time interval in which driving voltage is applied to the actuator and a guard time interval in which a back electromotive force (BEMF) signal of the actuator is detected, while correcting the length of the driving time interval according to detection time of a zero cross point of the BEMF signal detected within the guard time interval; and an actuator braking step of outputting at least one brake signal in synchronization with a zero cross point of the BEMF signal detected within the guard time interval, in order to remove residual vibration of the actuator.