Methods and related systems of a readout circuit for use with a wheatstone bridge sensor

Patent metadata

Field	Value
Publication number	US-11079413-B2
Application number	US-201715856334-A
Country	US
Kind code	B2
Filing date	Dec 28, 2017
Priority date	Dec 28, 2017
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A readout circuit for use with a Wheatstone bridge sensor. At least some of the example embodiments are methods including: driving an excitation signal in parallel through a first set of sensor elements of a Wheatstone bridge sensor and refraining from driving the excitation signal through a second set of sensor elements of the Wheatstone bridge sensor; measuring response of the first set of sensor elements, the measuring response of the first set of sensor elements creates a first measurement; and then driving the excitation signal in parallel through the second set of sensor elements of the Wheatstone bridge and refraining from driving the excitation signal through the first set of sensor elements; and measuring response of the second set of sensor elements, the measuring response of the second set of sensor elements creates a second measurement.

First claim

What is claimed is:

1. A method comprising:
driving a first excitation signal to a first port defined between a first sensor element and a second sensor element of a Wheatstone bridge sensor, and refraining from driving the first excitation signal to a second port defined between a third sensor element and a fourth sensor element of the Wheatstone bridge sensor;
measuring response of the first and second sensor elements, the measuring response of the first and second sensor elements creates a first measurement; and then
driving a second excitation signal to the second port of the Wheatstone bridge sensor and refraining from driving the second excitation signal to the first port; and
measuring response of the third and fourth sensor elements, the measuring response of the third and fourth sensor elements creates a second measurement.

2. A method comprising:
driving a first electrical current to a first port of a Wheatstone bridge sensor, and electrically floating a second port of the Wheatstone bridge sensor, first port defined between a first set of sensor elements of the Wheatstone bridge sensor and the second port defined between a second set of sensor elements of the Wheatstone bridge sensor;
measuring response of the first set of sensor elements, the measuring response of the first set of sensor elements creates a first measurement; and then
driving a second electrical current to the second port of the Wheatstone bridge sensor, and electrically floating the first port of the Wheatstone bridge sensor; and
measuring response of the second set of sensor elements, the measuring response of the second set of sensor elements creates a second measurement.

3. The method of claim 2 further comprising detecting failure of a sensor element of the first set of sensor elements based on the first measurement and the second measurement.

4. The method of claim 2 :
wherein measuring response of the first set of sensor elements further comprises measuring a first analog signal across a third port and a fourth port of the Wheatstone bridge sensor; and
wherein measuring response of the second set of sensor elements further comprises measuring a second analog signal across the third port and the fourth port of the Wheatstone bridge sensor.

5. The method of claim 4 wherein measuring response of the first set of sensor elements further comprises:
controlling voltage across the third port and the fourth port such that the voltage across the third port and fourth port is substantially zero, the controlling by applying a balancing current to the third port and fourth port; and
determining the first measurement based on the balancing current.

6. The method of claim 5 wherein measuring response of the third and fourth sensor elements further comprises:
controlling voltage across the third port and fourth port such that the voltage across the third port and fourth port is substantially zero, the controlling by applying the balancing current to the third port and fourth port; and
determining the second measurement based on the balancing current.

7. A method comprising:
driving a first excitation signal to a first port defined between a first set of sensor elements of a Wheatstone bridge sensor, and refraining from driving the first excitation signal to a second port defined between a second set of sensor elements of the Wheatstone bridge sensor;
measuring response to the first set of sensor elements to create a first measurement by applying a balancing current to a third port and a fourth port of the Wheatstone bridge sensor, the applying by way of a digital-to-analog (D/A) converter such that a voltage across the third port and the fourth port is substantially zero, the first measurement based on the balancing current; and then
driving a second excitation signal to the second port of the Wheatstone bridge sensor and refraining from driving the second excitation signal to the first port;
measuring response of the second set of sensor elements to create a second measurement; and
creating a digital representation of the first measurement by:
reading, by an analog-to-digital (A/D) converter, an output signal from a differential amplifier electrically coupled to the third and fourth ports of the Wheatstone bridge sensor, the reading creates a digital value;
supplying the digital value to the D/A converter; and
creating the digital representation by averaging the digital value over a predetermined amount of time.

8. The method of claim 7 wherein reading the output signal and supplying the digital value to the D/A converter further comprises reading and supplying by way of a one-bit Sigma-delta A/D modulator.

9. The method of claim 7 wherein applying the balancing current further comprises applying the balancing current directly to the third port and fourth port of the Wheatstone bridge sensor.

10. The method of claim 7 wherein applying the balancing current further comprises applying the balancing current directly to differential outputs of the differential amplifier whose inverting and non-inverting inputs are coupled to the first and second ports of the Wheatstone bridge sensor.

11. A sensor circuit comprising:
a first, second, third, and fourth sensor connections, the first, second, third, and fourth sensor connections configured to couple to a first, second, third, and fourth ports of a Wheatstone bridge sensor;
a switch network coupled to the third and fourth sensor connections, in a first mode the switch network couples a first current source to the third sensor connection and electrically floats the fourth sensor connection, and in a second mode couples a second current source to the fourth sensor connection and electrically floats the third sensor connection;
a differential amplifier that defines a first differential input, a second differential input, and a differential output, the first and second sensor connections electrically coupled to the first and second differential inputs, respectively;
an analog-to-digital (A/D) converter that defines an analog input and a digital output, the analog input electrically coupled to the differential output of the differential amplifier;
a digital-to-analog (D/A) converter that defines a digital input and an analog output, the digital input electrically coupled to the digital output of the A/D converter, and the analog output coupled to the first and second sensor connections;
a decimator coupled to the digital output of the A/D converter, the decimator configured to create measurement values based on values read from the digital output of the A/D converter; and
wherein, in the first mode the sensor circuit is configured to make a first measurement of a first set of sensors in the Wheatstone bridge sensor, and in the second mode the sensor circuit is configured to make a second measurement of a second set of sensors in the Wheatstone bridge sensor.

12. The sensor circuit of claim 11 wherein the switch network further comprises:
a first electrical switch that defines a common terminal, a first terminal, and a second terminal, the common terminal coupled to the first current source, and the first terminal coupled to the third sensor connection, in the first mode the first electrical switch couples the third sensor connection to the first current source and the switch network electrically floats the fourth sensor connection;
a second electrical switch that defines a common terminal, a first terminal, and a second terminal, the common terminal of the second electrical switch coupled to the second current source, and the first terminal of the second electrical switch coupled to the fourth sensor connection, in the second mod

Assignees

• Semiconductor Components Ind Llc

Inventors

• Bertin Jacques Jean
• Janssens Johan Camiel Julia
• Vermeir Sam Jan Ben Willem

Classifications

• G01K7/206 Primary

  in a potentiometer circuit · CPC title

• G01L27/007

  Malfunction diagnosis, i.e. diagnosing a sensor defect · CPC title

• G01R17/06 Primary

  Automatic balancing arrangements · CPC title

• G01R19/2506

  Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values (G01R19/003 takes precedence); Details concerning sampling, digitizing or waveform capturing (displaying waveforms G01R13/00; analog sampling G01R19/0053) · 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