This implementation exhibits greatly reduced chargefeedthrough, and circuit behaviour is in accordance with a modification to the firstorder analysis that includes the effects of chargefeedthrough.
Importantly, no frequency locking and much reduced jitter is observed.
This thesis reports an investigation into integrated interface circuits for switched capacitor sensors for application in industrial process control instrumentation networks.
Three circuits are presented: an absolute capacitance to voltage converter; a capacitance ratio to frequency ratio converter; and a capacitance ratio to voltage ratio converter.
In addition to extending the battery life by providing a low quiescent current, the regulator must be able to supply very low load currents and operate without off-chip capacitors.[Publication 1]: Matti Paavola, Mika Laiho, Mikko Saukoski, and Kari Halonen. A 3 µW, 2 MHz CMOS frequency reference for capacitive sensor applications. In: Proceedings of the 2007 IEEE International Symposium on Circuits and Systems (ISCAS 2007).
In: Proceedings of the 2006 IEEE International Symposium on Circuits and Systems (ISCAS 2006).
Initial investigations, accomplished with discrete component implementations of the interface circuits, reveal a significant departure in behaviour from that predicted by firstorder analysis.
Switch induced chargefeedthrough is shown to be responsible for the deviation.
Because the author made the main contribution to the design of the reference and power management circuits required, the overview part is dominated by the following research topics: current, voltage, and temperature references, frequency references, and voltage regulators. A micropower ΔΣ-based interface ASIC for a capacitive 3-axis micro-accelerometer.
After an introduction to capacitive micro-accelerometers, the work describes the typical integrated readout electronics of a capacitive sensor on the functional level. © 2008 Institute of Electrical and Electronics Engineers (IEEE). IEEE Journal of Solid-State Circuits, volume 44, number 11, pages 3193-3210.