A Comparison of Two Excitation Modes for MEMS Electrothermal Displacement Sensors

Abstract — MEMS electrothermal displacement sensors can be operated in constant current (CC) or constant voltage (CV) excitation modes. The CV mode is more commonly used. How-ever, there have been reports that the CC excitation mode may lead to a larger measured signal, and thus, it may be a better choice than the CV mode. In this letter, we present an analytic comparison of the two methods, and show that from a signal-to-noise-ratio point of view, benefits of operating a sensor in CC mode are only marginal. The analytical investigation is supported by experiments performed on sensors integrated in a SOI-MEMS nanopositioner with low noise read out circuits, which leads t