Digital direct-drive speaker system using MEMS speakers

In this paper, we propose a combination of regenerative circuits, a digital direct-drive system, and an intersymbol interference shaper to compensate for the shortcomings of MEMS speakers. Simulations and measurements were performed to verify the drive waveform, distortion rate, and sound pressure. Compared with the evaluation board, a lower driving voltage of 10 V and total harmonic distortion reduced by approximately 8 dB were confirmed for equivalent output sound pressure levels.