Capacitance Measurement Methods for Integrated Sensor Applications

In this paper different measurement methods that have been used for integrated capacitance measurement are reviewed and their advantage and disadvantages are discussed. For the designers of high accuracy on chip integrated circuits for capacitive sensors, it is important to know which method will provide the best approach for high accuracy, small chip area and power consumption especially for array sensors. These methods include on chip capacitive sensor and transducer measurement techniques that have been implemented for low value capacitance evaluations using CMOS technology. After the best structure is known the designer can optimize the chip for specific application. Voltage mode and current mode, linear and switched mode techniques are reviewed and a useful comparison table comparing all figures of merit including accuracy, range of measurement, chip area, speed and complexity is provided. The provided comparison table can be used as a reference for analog designers in the design of high accuracy integrated capacitive sensor interface.