A 24V Thin-Film Ultrasonic Driver for Haptic Feedback in Metal-Oxide Thin-Film Technology using Hybrid DLL Locking Architecture

Abstract

This paper presents a 24V high voltage (HV) ultrasonic driver for haptic feedback, designed to drive piezo-electric micromachined ultrasonic transducers (PMUT) using a unipolar 0.8um indium-galium-zinc-oxide (IGZO) thin-film transistor technology fabricated on a polymer substrate. A new hybrid DLL architecture is proposed to overcome the IGZO technology's shortcomings and leverage the accuracy and speed capabilities of Silicon technology. The ultrasonic driver is able to drive a transducer capacitance up to 36pF with a 4bit phase resolution and a frequency of 250kHz occupying a pitch matched area per pixel of $800\mu\mathrm{m}\times 800\mu m$. This work presents the first fully integrated high-voltage ultrasonic driver in thin-film technology, further expanding the possible applications for thin-film technologies.