Capacitive occupancy or proximity detector

US10126149B2 · kind B2 · utility

Assignee

• IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A. · LU

Inventors

• Michael Virnich · Korlingen, DE
• Michael Putz · Trier, DE
• Laurent Lamesch · Reichlange, LU
• Jochen Landwehr · Trier, DE

Key dates

• Filing date: Aug 20, 2015
• Grant date: Nov 13, 2018
• Expiry date: Aug 20, 2035

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03K2217/960705
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A capacitive occupancy or proximity detector includes a heating circuit, an impedance measurement circuit connected to the heating element, and a diagnostic circuit configured for determining integrity of the heater element. The heating circuit includes a heating element, a heating current source and a common mode choke having a first and a second winding, the heating element being connectable to the heating current source via the first and second windings. The diagnostic circuit includes at least one controllable switching element coupled across the second winding, circuitry for injecting a DC current into a series connection formed by the first winding the heating element and a parallel connection of the second winding and the at least one controllable switching element, and at least one detection circuit for detecting a voltage variation across the second winding.