Circuit, method and sensor for obtaining information on a physical quantity

Patent metadata

Field	Value
Publication number	US-9488505-B2
Application number	US-201314064462-A
Country	US
Kind code	B2
Filing date	Oct 28, 2013
Priority date	Oct 28, 2013
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A circuit for obtaining information on a physical quantity according to an embodiment includes a sensor arrangement sensitive to the physical quantity, at least one further sensor element sensitive to the physical quantity and a supply circuit configured to provide the sensor arrangement with a supply signal comprising a supply voltage controlled by the supply circuit in a closed-loop configuration. The supply circuit is further configured to provide the at least one further sensor element with a further supply signal comprising a further supply current such that a magnitude of the further supply current fulfills a predetermined relationship with a magnitude of a supply current of the supply signal. As a consequence, it may be possible to improve a trade-off between an improved compensation of variations, simplifying an implementation, simplifying the manufacturing, simplifying the sensing and providing stable sensing conditions.

First claim

What is claimed is:

1. A circuit for obtaining information on a physical quantity, the circuit comprising:
a sensor arrangement sensitive to the physical quantity;
at least one further sensor element sensitive to the physical quantity;
a supply circuit configured to provide the sensor arrangement with a supply signal comprising a supply voltage controlled by the supply circuit in a closed-loop configuration, wherein the supply circuit is further configured to provide the at least one further sensor element with a further supply signal comprising a further supply current such that a magnitude of the further supply current fulfills a predetermined relationship with a magnitude of a supply current of the supply signal; and
a detection circuit coupled to the at least one further sensor element and configured to generate an output signal indicative of the information on the physical quantity,
wherein the detection circuit comprises a differential amplifier coupled to the at least one further sensor element and configured to generate the output signal indicative of the information on the physical quantity,
wherein a first input of the differential amplifier is coupled to the supply circuit to receive a first signal comprising the supply voltage of the supply signal, wherein a second input of the differential amplifier is coupled to the at least one further sensor element to receive a second signal comprising a sensing voltage indicative of a voltage drop across the at least one further sensor element, and wherein the differential amplifier is configured to provide the output signal based on a difference of the supply voltage and the sensing voltage at an output of the differential amplifier.

2. The circuit according to claim 1 , wherein the supply circuit is configured such that according to the predefined relationship the magnitude of the further supply current is essentially proportional to the magnitude of the supply current.

3. The circuit according to claim 2 , wherein the supply circuit comprises a current mirror configured to provide the further supply signal with the magnitude of the further current based on the magnitude of the supply current of the supply signal.

4. The circuit according to claim 3 , wherein the current mirror is further configured to provide the supply signal with a magnitude of the current and the further supply signal with a magnitude of the further current based on a magnitude of a control current.

5. The circuit according to claim 4 , wherein the supply circuit is configured to control a magnitude of the control current such that the supply voltage of the supply signal is controlled in the closed-loop configuration.

6. The circuit according to claim 1 , wherein the supply circuit is configured to keep the magnitude of the supply voltage of the supply signal essentially constant.

7. The circuit according to claim 1 , wherein the sensor element arrangement comprises a plurality of sensor elements being sensitive to the physical quantity, the sensor element arrangement being configured to generate a signal indicative of a spatial change of the physical.

8. The circuit according to claim 7 , wherein at least two sensor elements of the sensor element arrangement are spatially shifted along a direction and coupled such that the sensor element arrangement is configured to generate the signal indicative of the spatial change of the physical quantity along the direction.

9. The circuit according to claim 7 , wherein at least two sensor elements of the sensor element arrangement are coupled to each other to form at least one half bridge, the at least one half bridge comprising at least two sensor elements and a node coupled between the at least two sensor elements, wherein the signal indicative of the spatial change is obtainable at the node of the at least one half bridge.

10. The circuit according to claim 9 , wherein the sensor element arrangement comprises at least two half bridges coupled in parallel such that the signal indicative of the spatial change is obtainable at the nodes of the at least two half bridges.

11. The circuit according to claim 1 , wherein the physical quantity comprises at least one of a strength of a magnetic field, a direction of the magnetic field, a strength of a component of a magnetic field, a temperature, a pressure, an intensity of an electromagnetic radiation, a frequency of the electromagnetic radiation, a wavelength of the electromagnetic radiation, and a mechanical stress.

12. The circuit according to claim 1 , wherein the sensor arrangement comprises at least one sensor element, and wherein the at least one sensor element of the sensor element arrangement and the further sensor element comprise at least one of a magnetic field sensitive sensor element, a temperature sensor element, a pressure sensor element, a light detecting sensor element and a sensor element sensitive to mechanical exposure.

13. A method for obtaining information on a physical quantity, the method comprising:
providing a sensor arrangement with a supply signal comprising a supply voltage controlled by a supply circuit in a closed-loop configuration, the sensor arrangement being sensitive to the physical quantity;
providing at least one further sensor element with a further supply signal comprising a further supply current such that a magnitude of the further supply current fulfills a predetermined relationship with a magnitude of a supply current of the supply signal, wherein the at least one further sensor element is sensitive to the physical quantity; and
providing a detection circuit coupled to the at least one further sensor element and configured to generate an output signal indicative of the information on the physical quantity, wherein the detection circuit comprises a differential amplifier coupled to the at least one further sensor element and configured to generate the output signal indicative of the information on the physical quantity;
receiving a first signal comprising the supply voltage of the supply signal at a first input of the differential amplifier coupled to the supply circuit;
receiving a second signal comprising a sensing voltage indicative of a voltage drop across the at least one further sensor element at a second input of the differential amplifier coupled to the at least one further sensor element; and
providing the output signal based on a difference of the supply voltage and the sensing voltage at an output of the differential amplifier by the differential amplifier.

14. A sensor for obtaining information on a physical quantity, the sensor comprising:
a sensor arrangement sensitive to the physical quantity;
at least one further sensor element sensitive to the physical quantity;
a supply circuit configured to provide the sensor arrangement with a supply signal comprising a supply voltage controlled by the supply circuit in a closed-loop configuration, wherein the supply circuit is further configured to provide the at least one further sensor element with a further supply signal comprising a further supply current such that a magnitude of the further supply current fulfills a predetermined relationship with a magnitude of a supply current of the supply signal; and
a detection circuit coupled to the at least one further sensor element and configured to generate an output signal indicative of the information on the physical quantity,
wherein the detection circuit comprises a differential amplifier coupled to the at least one further sensor element and configured to generate the output signal indicative of the information on the physical quantity,
wherein a first input of the different

Assignees

• Infineon Technologies Ag

Inventors

• Michelutti Alessandro
• Schaffer Bernhard
• Horn Wolfgang
• Hainz Simon

Classifications

• G05F3/262

  using field-effect transistors only · CPC title

• G01D11/00 Primary

  Component parts of measuring arrangements not specially adapted for a specific variable (G01D13/00, G01D15/00 take precedence) · CPC title

• G01D3/028 Primary

  mitigating undesired influences, e.g. temperature, pressure · CPC title