Contents I. Introduction
With the continuous development of emerging fields such as artificial intelligence, the Internet of Things, and biomedicine, the demand for detecting various physical, chemical, and other variables has become increasingly vital. Capacitive sensors are widely used to measure multiple variables such as pressure [1], humidity [2], acceleration [3], and toxic gases due to their advantages of no static power consumption, high sensitivity, and good temperature characteristics. In the above case, long-time monitoring is necessary. For example, intracranial pressure monitoring for medical diagnosis and atmospheric pressure monitoring for weather prediction require incredibly long working hours, which puts forward relatively stringent power consumption requirements for the sensing system. The interface circuit, also named capacitance-to-digital converter (CDC) for capacitive sensors, as the primary contributor to the system power, should be designed to consume low power. Various implementation methods have been proposed for the interface circuit in recent years.
