Abstract: A circuit for driving a transducer in a mid-air haptic system includes a voltage source, a voltage sink, a current source, a trickle capacitor, a storage capacitor, a haptic system transducer, a first switch, a second switch, and a third switch. Using these components, a portion of the charge required for switching a transducer is sourced from the decoupling capacitance. When the switching completes, additional charge is transferred immediately from the power supply back into the decoupling capacitance. This acts to lower the peak current by fully utilizing 100% of a switching waveform for transfer of charge from the power supply to capacitors local to the transducer.

Abstract: As control points in haptic systems move around, the phase offsets for each transducer change at discrete points in time. These are each expressed as a phase offset combined with a monochromatic carrier frequency. To prevent sharp frequency changes, an algorithm that maintains smooth transitions is used. Further, non-idealities in the implementation of haptic array modulation can create spurs in the frequency response of audio output from the array. Adjusting the signal carrier frequency and the signal modulating frequency may substantially reduce audio noise via a notch filter centered at an interpolation frequency.

Abstract: A circuit for driving a transducer in a mid-air haptic system includes a voltage source, a voltage sink, a current source, a trickle capacitor, a storage capacitor, a haptic system transducer, a first switch, a second switch, and a third switch. Using these components, a portion of the charge required for switching a transducer is sourced from the decoupling capacitance. When the switching completes, additional charge is transferred immediately from the power supply back into the decoupling capacitance. This acts to lower the peak current by fully utilizing 100% of a switching waveform for transfer of charge from the power supply to capacitors local to the transducer.