US 12,474,185 B2
Capacitive sensor device with drift compensation
Chaouki Rouaissia, Neuchâtel (CH); Sébastien Grisot, Bourdry (CH); and Jerald G. Ott, III, Escondido, CA (US)
Assigned to Semtech Corporation, Camarillo, CA (US)
Filed by Semtech Corporation, Camarillo, CA (US)
Filed on Apr. 25, 2023, as Appl. No. 18/138,985.
Claims priority of provisional application 63/335,508, filed on Apr. 27, 2022.
Prior Publication US 2023/0349730 A1, Nov. 2, 2023
Int. Cl. G01D 5/24 (2006.01); G01R 27/26 (2006.01); H03K 17/955 (2006.01)
CPC G01D 5/24 (2013.01) [G01R 27/2605 (2013.01); H03K 17/955 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A capacitive sensor device comprising a capacitance-measuring circuit, a main sense input and a reference sense input, wherein the capacitive sensor device is configured to measure, using the capacitance-measuring circuit, a current main value of capacitance seen by the main sense input and a current reference value of capacitance seen by the reference sense input, wherein the capacitive sensor device is configured to at least temporarily store at least one previously measured reference value, and wherein the capacitive sensor device is configured to use
the current main value,
the current reference value and the at least one previously measured reference value, and
at least one current correction coefficient, with the capacitive sensor device being configured to adaptively determine the at least one current correction coefficient based on at least the current reference value and the at least one previously measured reference value,
for determining a corrected current main value of capacitance
wherein the main sense input is coupled with a capacitive sense electrode whose self-capacitance changes at an approach of a conductive body, and
wherein the reference sense input is coupled with a capacitive reference electrode, the capacitive reference electrode being a discrete reference capacitor arranged to measure a capacitance that is sensitive to environment drift.