Method for sensor readout with redundancy-checking

Patent metadata

Field	Value
Publication number	US-10067173-B2
Application number	US-201715680937-A
Country	US
Kind code	B2
Filing date	Aug 18, 2017
Priority date	Apr 11, 2011
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A method for reading out a sensor unit having a first set of nodes and a second set of nodes and a symmetry which allows different configurations of excitation and sensing lead to a same readout. The method includes changing the readout configuration of the sensor unit by exchanging excitation and sensing between the first set of nodes and the second set of nodes, evaluating the similarity or deviation between measurement signals obtained in different readout configurations of the sensor unit, raising an error if the measurement signals differ more from one another than a predetermined value.

First claim

The invention claimed is:

1. A method for reading out a sensor unit having a first set of nodes and a second set of nodes, said sensor unit having a symmetry which allows different configurations of excitation and sensing lead to a same readout, the method comprising:
changing the readout configuration of the sensor unit by exchanging excitation and sensing between the first set of nodes and the second set of nodes, said exchanging comprising using switching units such as to switch excitation signals emanating from excitation nodes from being applied to the first set of nodes to being applied to the second set of nodes and to switch differential measurement signals measured at sensing nodes from being obtained from the second set of nodes to being obtained from the first set of nodes; and
evaluating the similarity or deviation between measurement signals obtained in different readout configurations of the sensor unit, said different readout configurations corresponding to different states of said switching units, raising an error if the measurement signals differ more from one another than a predetermined value.

2. The method according to claim 1 , wherein evaluating the similarity or deviation between measurement signals obtained in different readout configurations of the sensor unit includes evaluating the similarity or deviation of differential output signals of the sensor unit.

3. The method according to claim 1 , wherein evaluating the similarity or deviation between measurement signals obtained in different configurations of the sensor unit includes evaluating the similarity or deviation of measurement signals at excitation nodes resulting from a current and/or a voltage applied as an excitation signal to the sensor unit at these excitation nodes.

4. The method according to claim 1 , furthermore comprising determining a linear combination of voltages at the first set of nodes and/or at the second set of nodes and delivering this as measurement signal.

5. The method according to claim 1 , wherein evaluating the similarity or deviation between measurement signals obtained in different configurations of the sensor unit comprises collecting measurement signals at different time instants.

6. The method according to claim 5 , further comprising collecting readout values obtained at the first and the second set of nodes, during subsequent readout operations, and wherein said readout values obtained at the first and the second set of nodes are compared and an error is raised if these readout values differ more than a pre-determined value.

7. The method according to claim 6 , wherein said comparing includes taking the difference between the readout values obtained at the first and the second set of nodes.

8. The method according to claim 6 , wherein said comparing includes statistical and/or model based inference techniques.

9. The method according to claim 1 , wherein evaluating the similarity or deviation between measurement signals obtained in different configurations of the sensor unit comprises raising an error if the measurement signals differ more from one another than a predetermined value.

10. The method according to claim 1 , furthermore comprising changing the sign of excitation signals applied to the sensor unit and of sensing signals read from the sensor unit.

11. The method according to claim 10 , further comprising sequencing through different configurations with regard to switching between excitation of and sensing at sets of nodes and with regard to changing sign of excitation and sensing signals, and collecting measurement data from said different configurations.

12. The method according to claim 11 , wherein said sequencing through different configurations comprises sequencing through the configurations in a random way.

13. The method according to claim 1 , wherein changing the readout configuration of the sensor unit is performed during actual use of the sensor unit.

14. The method according to claim 1 , wherein sensing between the first set of nodes and sensing between the second set of nodes both comprise a bridge readout.

15. A method for reading out a sensor unit having a first set of nodes and a second set of nodes, said sensor unit having a symmetry which allows different configurations of excitation and sensing lead to a same readout, the method comprising:
changing the readout configuration of the sensor unit by exchanging excitation and sensing between the first set of nodes and the second set of nodes, said exchanging comprising using switching units such as to switch excitation signals emanating from excitation nodes from being applied to the first set of nodes to being applied to the second set of nodes and to switch differential measurement signals measured at sensing nodes from being obtained from the second set of nodes to being obtained from the first set of nodes;
evaluating the similarity or deviation between measurement signals obtained in different readout configurations of the sensor unit, said different readout configurations corresponding to different states of said switching units, raising an error if the measurement signals differ more from one another than a predetermined value;
changing the sign of excitation signals applied to the sensor unit and of sensing signals read from the sensor unit;
sequencing through different configurations with regard to switching between excitation of and sensing at sets of nodes and with regard to changing sign of excitation and sensing signals; and
collecting measurement data from said different configurations,
wherein said sequencing through said configurations comprises sequencing in a systematic way with oversampling at a rate such that an equality of the measurement signals of subsequent samples can be assumed under normal operation, and wherein said similarity or deviation between measurement signals obtained in subsequent readout configurations, during said sequencing, provides information about a reliability of the sensor.

16. A method for reading out a sensor unit having a first set of nodes and a second set of nodes, said sensor unit having a symmetry which allows different configurations of excitation and sensing lead to a same readout, the method comprising:
changing the readout configuration of the sensor unit by exchanging excitation and sensing between the first set of nodes and the second set of nodes, said exchanging comprising using switching units such as to switch excitation signals emanating from excitation nodes from being applied to the first set of nodes to being applied to the second set of nodes and to switch differential measurement signals measured at sensing nodes from being obtained from the second set of nodes to being obtained from the first set of nodes;
evaluating the similarity or deviation between measurement signals obtained in different readout configurations of the sensor unit, said different readout configurations corresponding to different states of said switching units, raising an error if the measurement signals differ more from one another than a predetermined value; and
electrically coupling excitation circuitry, using said switching units, to said first set of nodes or to said second set of nodes depending on the configuration of the switching units, said excitation circuitry comprising a first excitation source electrically connected to a first switching unit and a second excitation source electrically connected to a second switching unit for providing a symmetrical excitation to the sensor unit.

17. The method according to claim 16 , wherein said electrically c

Assignees

• Melexis Tech N V
• Melexis Tech Sa

Inventors

• Raman Johan
• Rombouts Pieter

Classifications

• G01L1/2262

  involving simple electrical bridges · CPC title

• G01L1/144 Primary

  with associated circuitry (G01L1/146 and G01L1/148 take precedence) · CPC title

• G01R31/2829

  Testing of circuits in sensor or actuator systems (testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844) · CPC title

• G01L9/02

  by making use of variations in ohmic resistance, e.g. of potentiometers {, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning} · CPC title

• G01R31/003 Primary

  Environmental or reliability tests (of individual semiconductors G01R31/2642; of PCB's G01R31/2817; of IC's G01R31/2855; of other circuits G01R31/2849) · CPC title