Differential capacitive rain sensor

摘要

A differential capacitive rain sensor comprising a differential sensing capacitor having at least a first drive electrode, a second drive electrode and a sense electrode. A driving circuit is coupled to the first and the second drive electrodes for driving the first drive electrode with a first drive signal and the second drive electrode with a second drive signal, the second drive signal being substantially opposite in phase to the first drive signal. The sensor comprises a detection circuit having an input coupled to the sense electrode for detecting a change in a sense signal of the sense electrode. The detection circuit further comprises a controller using an error signal derived from the sense signal to control the amplitude of the first and/or the second drive signal so as to reduce the amplitude of the sense signal.