@conference {chaput201721, title = {21.5 A 3-to-5V input 100V pp output 57.7 mW 0.42\% THD+ N highly integrated piezoelectric actuator driver}, booktitle = {2017 IEEE International Solid-State Circuits Conference (ISSCC)}, year = {2017}, pages = {360{\textendash}361}, publisher = {IEEE}, organization = {IEEE}, address = {San Francisco, CA, USA}, abstract = {Piezoelectric actuators are used in a growing range of applications, e.g., haptic feedback systems, cooling fans, and microrobots. However, to fully realize their potential, these actuators require drivers able to efficiently generate high-voltage (\>100V pp ) low frequency (\<;300Hz) analog waveforms from a low-voltage source (3-to-5V) with small form factor. Certain applications, such as piezoelectric (PZT) cooling fans, further demand low distortion waveforms (THD+N \<; 1\%) to minimize sound emission from the actuator. Existing solutions for small PZT drivers typically rely on designs comprising a power converter to step up a low voltage followed by a high-voltage amplifier [1,2,3]. Although envelope tracking can help reduce amplifier power [3], none of these designs can recover the energy stored on the actuator to maximize efficiency. And while a differential bidirectional flyback converter [4] can recover energy, it requires four inductors, thereby incurring large size penalty. This paper introduces a single-inductor, highly integrated, bidirectional, high-voltage actuator driver that achieves 12.6{\texttimes} lower power and 2.1{\texttimes} lower THD+N at a similar size to the currently available state-of-the art solution [1]. Measured results from an IC prototype demonstrate 200Hz sinusoidal waveforms up to 100V pp with 0.42\% THD+N from a 3.6V source while dissipating 57.7mW to drive a 150nF capacitor. Beyond PZT actuators, the IC can also drive any type of capacitive load, e.g., electrostatic and electroactive polymer actuators.}, url = {https://doi.org/10.1109/ISSCC.2017.7870410}, author = {Simon Chaput and David Brooks and Gu Wei} }