Sense coil geometries with improved sensitivity for metallic object detection in a predetermined space

US10122192B2 · kind B2 · utility

Assignee

• QUALCOMM Incorporated · US

Inventors

• Swagat Chopra · Munich, DE
• Leandro Percebon · Munich, DE
• Michael Werner · Marloffstein, DE

Key dates

• Filing date: Aug 4, 2015
• Grant date: Nov 6, 2018
• Expiry date: Nov 12, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T90/14
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

This disclosure provides systems, methods and apparatus for detecting a presence of an object. In one aspect an apparatus for detecting a presence of an object is provided. The apparatus includes a sense coil formed from a conductor having a predetermined shape configured to attenuate currents induced in the conductor by an external time-varying magnetic field. The sense coil has an electrical characteristic that varies as a function of the presence of the object. The apparatus comprises a detection circuit coupled to the sense coil and configured to detect the presence of the object in response to detecting a difference between a measured value of the electrical characteristic and a reference value for the electrical characteristic. The reference value for the electrical characteristic is substantially the same as the measured value of the electrical characteristic in the absence of the object over at least a portion of the sense coil.