Patent ID: 9442143
Filing Date: 2016-09-13
CPC Classification: G01R,H03K

Claim Text:
1. Capacitive proximity sensor, comprising a first sensor electrode and a second sensor electrode, a signal generator configured to provide a differential alternating signal comprising a first electric alternating signal and a second electric alternating signal, a first load element, which comprises a first electric load and a second electric load, wherein the first electric alternating signal is fed to the first sensor electrode through the first electric load and the second electric alternating signal is fed to the second sensor electrode through the second electric load, and wherein the first and second electric loads together with a capacitive load to be measured at the respective sensor electrode form a lowpass filter, respectively; a second load element having an input coupled with the signal generator and an output providing a differential output signal; and a signal processing device coupled with the first sensor electrode and with the second sensor electrode, wherein the signal processing device comprises a first differential amplifier receiving a difference between the differential output signal of the second load element and a differential signal provided by signals from the first and second sensor electrodes, respectively.