Iee International Electronics and Engineering S.a.

Tobias Justinger

Laurent Lamesch

Christoph Wendt

Thomas Faber

Michael Puetz

Michael Pütz

Johnny Lorang

An impedance measurement circuit for determining a complex impedance of a capacitive sensor having at least one sense electrode operable in loading mode and at least one guard electrode. The measurement circuit includes: a pulse generator unit for providing a periodic electric measurement signal and a periodic electric guard signal; a signal sensing circuit for sensing a sense current flowing through the at least one sense electrode or the sense electrodes in response to the pulse generator unit measurement signal; and a control and evaluation unit. The control and evaluation unit is configured for determining a complex impedance from the determined sense currents with reference to a complex reference potential.

Low-cost, high measurement speed capacitive sensing circuit for loading mode operation of capacitive sensors

An impedance measurement circuit for determining a complex impedance of a capacitive sensor that is configured for employing at least one electric heater member as an electrode to be operated in loading mode. The measurement circuit includes: a signal generating unit for providing an electric measurement signal; a signal sensing circuit measuring current through the at least one electric heater member; an electric heater member connection circuit comprising a plurality of MOSFETs for selectively electrically connecting the electric heater member either to the signal sensing circuit for complex impedance measurement or to a DC electric power unit for heating purposes; and a control and evaluation unit that is configured for controlling a switching status of the plurality of MOSFETs according to a predefined sequence, and for determining a complex impedance from the determined currents with reference to a complex reference potential during predefined stages of the predefined sequence.

Low-cost, protected capacitive sensing circuit for loading mode operation of capacitive sensors employing heater members

A system for hand detection on a steering wheel. The system includes: at least one light source adapted to emit an emitted signal of light so that the emitted signal is directed from inside the steering wheel to at least one detection area of a surface of the steering wheel, the detection area being at least partially transparent for the emitted signal; at least one light sensor adapted to detect a reflected signal, which is a part of the emitted signal that is reflected from the detection area into the inside of the steering wheel; and a detection unit coupled to the at least one light sensor and adapted to detect a hand of a user on the steering wheel based on a detection of the reflected signal.

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Hermeskeil, Germany

Tobias Justinger