3-Bit Digital-to-Analog Converter with Mechanical Amplifier for Binary Encoded Large Displacements

• Main Authors: Lisa Schmitt, Philip Schmitt, Martin Hoffmann
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Actuators
• Subjects: digital-to-analog converter; DAC; large displacements; electrostatic bending-plate actuator; mechanical amplifier; mechAMP
• Online Access: https://www.mdpi.com/2076-0825/10/8/182

We present the design, fabrication, and characterization of a MEMS-based 3-bit Digital-to-Analog Converter (DAC) that allows the generation of large displacements. The DAC consists of electrostatic bending-plate actuators that are connected to a mechanical amplifier (mechAMP), enabling the amplification of the DAC output displacement. Based on a parallel binary-encoded voltage signal, the output displacement of the system can be controlled in an arbitrary order. Considering the system design, we present a simplified analytic model, which was confirmed by FE simulation results. The fabricated systems showed a total stroke of approx. 149.5 ± 0.3 µm and a linear stepwise displacement of 3 bit correlated to 2³ ≙ eight defined positions at a control voltage of 60 V. The minimum switching time between two input binary states is 0.1 ms. We present the experimental characterization of the system and the DAC and derive the influence of the mechAMP on the functionality of the DAC. Furthermore, the resonant behavior and the switching speed of the system are analyzed. By changing the electrode activation sequence, 27 defined positions are achieved upgrading the 3-bit systems into a 3-tri-state (3³) system.