US 12,078,666 B2
Multi-channel capacitance sensing measurement circuit
Bernd Farsch, Schweich (DE); Attila Konfar, Oberbillig (DE); Christian Urig, Püttlingen (DE); Christoph Wendt, Trier (DE); and Laurent Lamesch, Reichlange (LU)
Assigned to IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A., Echternach (LU)
Appl. No. 17/602,773
Filed by IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A., Echternach (LU)
PCT Filed Apr. 7, 2020, PCT No. PCT/EP2020/059828
§ 371(c)(1), (2) Date Oct. 10, 2021,
PCT Pub. No. WO2020/207989, PCT Pub. Date Oct. 15, 2020.
Claims priority of application No. 101178 (LU), filed on Apr. 10, 2019; and application No. 101255 (LU), filed on May 29, 2019.
Prior Publication US 2022/0155355 A1, May 19, 2022
Int. Cl. G01R 27/26 (2006.01); G01R 19/00 (2006.01)
CPC G01R 27/2605 (2013.01) [G01R 19/0092 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A capacitance measurement circuit for determining complex electric currents in a multi-channel capacitive sensing device that includes a plurality of electrically conductive sense electrodes, each sense electrode being paired with at least one corresponding electrically conductive guard electrode, the capacitance measurement circuit comprising:
a first sensing circuit for selectively electrically connecting one of the sense electrodes to a common sense node and for electrically connecting the corresponding guard electrode of the sense electrode to a common guard node,
at least a second sensing circuit for selectively electrically connecting another one of the sense electrodes to the common sense node and for electrically connecting the corresponding guard electrode of the sense electrode to the common guard node,
a measurement signal voltage source that is configured for providing an alternating measurement voltage at an output port to the common guard node in a remotely controllable manner,
a diagnostic signal voltage source that is configured for providing an alternating diagnostic voltage at an output port to the common guard node in a remotely controllable manner, and
a current measurement circuit including at least one measurement current-to-voltage converter that is connected with its signal input port to the common sense node and with its reference input port to the output port of the measurement signal voltage source.