Magnetic sensor reading device, system and method

• US 10,473,731 B2
• Filed: 11/22/2011
• Issued: 11/12/2019
• Est. Priority Date: 11/26/2010
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Romani, Carlo Alberto, Pozzati, Enrico, Bottinelli, Fabio
• Primary Examiner(s): Ishizuka, Yoshihisa
• Application Number:
  US13/302,944
• Publication Number:
  US 20120158324A1
• Time in Patent Office: 2,912 Days
• Field of Search: 702 57
• CPC Class Codes: G01R 33/0017 Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields
• CPC Class Codes: G01R 33/0023 Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration G01R33/0017 takes precedence
• CPC Class Codes: G01R 33/0035 Calibration of single magnetic sensors, e.g. integrated calibration
• CPC Class Codes: G01R 33/06 using galvano-magnetic devices
• CPC Class Codes: G01R 33/09 Magnetoresistive devices
• CPC Class Codes: G01R 33/096 anisotropic magnetoresistance sensors
• CPC Class Codes: G01R 35/00 Testing or calibrating of apparatus covered by the other groups of this subclass

Abstract

A reading circuit for a magnetic-field sensor, provided with a detection structure generating an electrical detection signal as a function of an external magnetic field, has a signal-conditioning stage, which is electrically coupled to the detection structure and generates an output signal as a function of the electrical detection signal; the reading circuit is provided with a full-scale-control stage that is able to select automatically a full-scale value for the signal-conditioning stage, as a function of the value of the external magnetic field, such as to prevent saturation of the same conditioning stage.

Claims

1. A device, comprising:

signal processing circuitry configured to receive a detection signal indicative of one or more characteristics of a magnetic field and to generate an output signal as a function of said detection signal, the signal processing circuitry having a range of full-scale gain settings; and

control circuitry communicatively coupled to said signal processing circuitry, wherein the control circuitry, in operation, automatically selects a full-scale gain setting of the range of full-scale settings of the signal processing circuitry, the selecting including responding to detection of saturation of the signal processing circuitry by iteratively selecting full-scale gain settings of the range of full-scale gain settings of said signal processing circuitry, until an absence of saturation of said signal processing circuitry at the selected full-scale gain setting of the signal processing circuitry is detected, and saturation of the signal processing circuitry is detected based on the output signal of the signal processing circuitry.

2. The device according to claim 1 wherein said control circuitry is configured to generate and to send to said signal processing circuitry a command signal based on the selected full-scale gain setting of said signal processing circuitry.

3. The device according to claim 2 wherein said signal processing circuitry comprises an amplifier having an electronically variable and selectable amplification gain, and said amplifier is configured to vary a value of said amplification gain based on the command signal, the iteratively-selected full-scale gain setting being a minimum setting selected from a set of settings of the range of full-scale gain settings which prevents saturation of the signal processing circuitry.

4. The device according to claim 1 wherein said iteratively selecting comprises:

selecting a first full-scale gain setting;

determining whether saturation of the signal processing circuitry is present at the first full-scale gain setting based on the output of the signal processing circuitry; and

when it is determined that saturation of the signal processing circuitry is present, incrementing the first full-scale gain setting.

5. The device according to claim 4 wherein said first full-scale gain setting is one of:

a minimum selectable setting and a default setting.

6. The device according to claim 1 wherein said control circuitry is activated in response to reception of an indication of a user demand.

7. The device according to claim 1 wherein said magnetic field comprises a useful component and a component of disturbance.

8. A system, comprising:

a detection structure configured to generate an electrical detection signal as a function of a magnetic field; and

reading circuitry configured to;

generate an output signal based on the electrical detection signal generated by the detection structure; and

automatically select a full-scale gain setting of a range of full-scale gain settings of the reading circuitry based on the output signal, wherein said reading circuitry is configured to respond to detection of saturation of the reading circuitry by iteratively selecting full-scale gain settings of the range of full-scale gain settings until an absence of saturation of said reading circuitry is detected, and to detect saturation of the reading circuitry based on the output signal.

9. The system according to claim 8 wherein said reading circuitry is configured to generate a command signal based on the selected full-scale gain setting.

10. The system according to claim 9 wherein said reading circuitry comprises an amplifier having an electronically variable and selectable amplification gain, and said amplifier is configured to vary a value of said amplification gain based on the command signal, the iteratively-selected full-scale gain setting being a minimum setting selected from a set of settings of the range of full-scale gain settings which prevents saturation of said reading circuitry.

11. The system according to claim 8 wherein said iteratively selecting comprises:

selecting a first full-scale gain setting;

determining whether saturation of the reading circuitry is present at the first full-scale gain setting based on the output signal; and

when it is determined that saturation of the reading circuitry is present, incrementing the first full-scale gain setting.

12. The system according to claim 11 wherein said first full-scale gain setting is one of:

a minimum selectable setting and a default setting.

13. The system according to claim 8 wherein said detection structure comprises magnetoresistive elements configured to form a bridge detection structure and said electrical detection is a signal indicative of an unbalancing of said bridge detection structure.

14. A method, comprising:

receiving an electrical detection signal indicative of at least one characteristic of a magnetic field;

generating, using a reading circuit, an output signal based on the electrical detection signal, the reading circuit having a range of full-scale gain settings; and

automatically selecting a full-scale gain setting of the range of full-scale gain settings of said reading circuit based on the output signal, wherein the selecting the full-scale gain setting comprises responding to detection of saturation of the reading circuit by iteratively selecting full-scale gain settings of said reading circuit until an absence of saturation of said reading circuit is detected, and saturation of the reading circuit is detected based on the output signal of the reading circuit.

15. The method of claim 14 wherein the iteratively-selected full-scale gain setting is a minimum setting from a set of settings at which saturation of said reading circuit is not detected.

16. The method of claim 14 wherein said iteratively selecting comprises:

selecting a first full-scale gain setting;

determining whether saturation is present at the first full-scale gain setting based on the output of the reading circuit; and

when it is determined that saturation is present, incrementing the first full-scale gain setting.

17. The method of claim 16 wherein said first full-scale gain setting is one of:

a minimum selectable setting and a default setting.

18. The method of claim 14, further comprising:

generating the electrical detection signal.