Environmental sensor circuit having a capacitive proximity sensor and magnetic field probe

Patent metadata

Field	Value
Publication number	US-12107575-B2
Application number	US-202217894837-A
Country	US
Kind code	B2
Filing date	Aug 24, 2022
Priority date	Sep 29, 2021
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

Environmental sensor circuit for a portable connected wireless device. The circuit includes a capacitive proximity sensor that determines when a user is close to the portable device. The device also has a magnetic field probe that provides a signal that indicates the position of a permanent magnet. The sensor circuit integrates both a digitizing unit and digital signal processing for the suppression of noise and drive in signals coming from the proximity sensor and from the magnetic field probe.

First claim

The invention claimed is:

1. An environmental sensor circuit for a portable connected wireless device, the circuit comprising: (a) a capacitive proximity sensor configured to determine whether a user is in proximity to the capacitive proximity sensor, by sensing variation in the capacitance of an electrode in electric connection with an environmental integrated circuit, (b) a magnetic field probe, providing a signal proportional to a magnetic field strength, wherein the environmental sensor circuit has an analogue/digital converter configured to produce proximity digital values representative of the capacitance of the electrode and magnetic field digital values representative of the magnetic field strength, the integrated circuit further comprising a digital processor configured for suppressing unwanted noise and drift components from the proximity digital values and from the magnetic field digital values.

2. The environmental sensor circuit according to claim 1 , comprising a magnetic field digital output, configured to switch from a logical state to an opposite logical state when the magnetic field sensed by the magnetic field probe exceeds a predetermined threshold.

3. The environmental sensor circuit according to claim 1 , wherein the digital processor comprises a nonlinear filter.

4. The environmental sensor circuit according to claim 1 , wherein the digital processor comprises a baseline and drift suppression unit.

5. The environmental sensor circuit according to claim 4 , the baseline and drift suppression unit being configured to subtract at least a part of a baseline component from an analogue signal presented at the input of the analogue/digital converter.

6. The environmental sensor circuit according to claim 1 , in which the magnetic field probe is a Hall-effect device, and the environmental sensor circuit and the Hall-effect device are fabricated on a same semiconductor chip.

7. The environmental sensor circuit according to claim 1 in a wireless portable connected device, wherein the wireless portable connected device is configured to reduce a RF power of the wireless portable connected device when the integrated circuit determine a proximity with the user, wherein a sensitivity of the proximity sensor is variable dependent on the magnetic field strength.

8. The environmental sensor circuit according to claim 1 , wherein the magnetic field probe is a multi-axis probe capable of detecting strengths of two or three independent components of the vectorial magnetic field.

9. The environmental sensor circuit according to claim 1 , comprising a digital bus output for communicating values of proximity and magnetic field to a host system.

10. The environmental sensor circuit according to claim 1 , comprising an interrupt output for requesting the action of a host system when the values of proximity and/or magnetic field meet predetermined conditions.

11. An environmental sensor circuit for a portable connected wireless device, the circuit comprising: (a) a capacitive proximity sensor configured to determine whether a user is in proximity to the capacitive proximity sensor, by sensing variation in the capacitance of an electrode in electric connection with an environmental integrated circuit, (b) a magnetic field probe, providing a signal proportional to a magnetic field strength, wherein the environmental sensor circuit has an analogue/digital converter configured to produce proximity digital values representative of the capacitance of the electrode and magnetic field digital values representative of the magnetic field strength, the integrated circuit further comprising a digital processor configured for suppressing unwanted noise and drift components from the proximity digital values and from the magnetic field digital values, the environmental sensor circuit further comprising a magnetic field digital output, configured to switch from a logical state to an opposite logical state when the magnetic field sensed by the magnetic field probe exceeds a predetermined threshold.

12. An environmental sensor circuit for a portable connected wireless device, the circuit comprising: (a) a capacitive proximity sensor configured to determine whether a user is in proximity to the capacitive proximity sensor, by sensing variation in the capacitance of an electrode in electric connection with an environmental integrated circuit, (b) a magnetic field probe, providing a signal proportional to a magnetic field strength, wherein the environmental sensor circuit has an analogue/digital converter configured to produce proximity digital values representative of the capacitance of the electrode and magnetic field digital values representative of the magnetic field strength, the integrated circuit further comprising a digital processor configured for suppressing unwanted noise and drift components from the proximity digital values and from the magnetic field digital values, the environmental sensor circuit further comprising a digital bus output for communicating values of proximity and magnetic field to a host system, and/or an interrupt output for requesting the action of a host system when the values of proximity and/or magnetic field meet predetermined conditions.

Assignees

• Semtech Corp

Inventors

• Rouaissia Chaouki

Classifications

• H03K17/9517

  using galvanomagnetic devices · CPC title

• H03K17/9512

  using digital techniques · CPC title

• G01B7/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title

• H04M2250/12

  including a sensor for measuring a physical value, e.g. temperature or motion · CPC title

• H04M1/72448

  with means for adapting the functionality of the device according to specific conditions · CPC title