US 12,332,092 B2
Drift suppression method, proximity sensor and wireless device
Chaouki Rouaissia, Neuchâtel (CH)
Assigned to Semtech Corporation, Camarillo, CA (US)
Filed by Semtech Corporation, Camarillo, CA (US)
Filed on Apr. 25, 2023, as Appl. No. 18/138,997.
Claims priority of provisional application 63/335,524, filed on Apr. 27, 2022.
Prior Publication US 2023/0349731 A1, Nov. 2, 2023
Int. Cl. G01D 5/24 (2006.01); G01R 27/26 (2006.01)
CPC G01D 5/24 (2013.01) [G01R 27/2605 (2013.01)] 16 Claims
OG exemplary drawing
 
7. A capacitive proximity sensor for a portable device, comprising a sense electrode and a readout circuit configured to read a self-capacitance of the sense electrode and provide a proximity signal including a series of capacitance values, the capacitive proximity sensor comprising a drift suppression unit configured to suppressing a drift superimposed on the proximity signals by the steps of:
computing repeatedly an average slope of the proximity signal from the capacitance values
comparing the average slope with a threshold,
updating a baseline value by adding a value derived from the proximity signal when the average slope is below the threshold or a fixed value when the average slope is above the threshold,
obtain a drift-suppressed proximity signal by subtracting the baseline value from the proximity signal.