Abstract: An electrical device providing audible and haptic communication with its user includes a touch screen, an array of piezoelectric elements, a memory, and a processor. The touch screen is divided into touch regions and each touch region carries one piezoelectric element. When receiving touch inputs from a user, the processor uses data and programs stored in the memory to (1) determine which touch region the touch input is located in, (2) determine which piezoelectric element corresponds to the determined touch region, and (3) vibrate the determined piezoelectric element at a predetermined frequency. The electrical device can output sound by (1) obtaining a signal of the sound to be output and (2) vibrating the piezoelectric element, or more than one at different predetermined frequencies, to output an audible sound.

Abstract: An envelope tracking device includes a fine slot peak tracking (FSPT) circuit, at least one power amplifier, and an envelope modulator. The FSPT circuit is connected to the power amplifier through the envelope modulator. The FSPT circuit generates envelope signals based on input signals, adds an offset to the envelope signals, and expands and smoothes the added envelope signals. The envelope modulator generates envelope voltage signals according to the smoothed envelope signals, and outputs the signals to drain of the power amplifier. The envelope voltage signals are time-aligned with the amplified signals which are transmitted to gate of the power amplifier.