CIRCUIT THAT PROVIDES OUTPUT VOLTAGES IN A HOMOGENOUS MAGNETIC FIELD

• US 20090295380A1
• Filed: 05/30/2008
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Werth, Tobias, Motz, Mario, Mialtu, Razvan-Catalin, Dineci, Stefan, Aldea, Valentin
• Granted Patent: US 7,952,350 B2
• Time in Patent Office: Days
• US Class Current: 324/251
• CPC Class Codes: G01R 33/072 Constructional adaptation of the sensor to specific applications

Abstract

A circuit including Hall plates and an amplifier. The Hall plates are configured to provide Hall voltages in a homogenous magnetic field such that a first Hall plate has a first positive voltage and a first negative voltage and a second Hall plate has a second positive voltage and a second negative voltage. The amplifier is configured to receive the Hall voltages and provide a first output voltage that corresponds to the first positive voltage and the second positive voltage and a second output voltage that corresponds to the first negative voltage and the second negative voltage.

Claims

1. A circuit, comprising:

Hall plates configured to provide Hall voltages in a homogeneous magnetic field such that a first Hall plate has a first positive voltage and a first negative voltage and a second Hall plate has a second positive voltage and a second negative voltage; and

an amplifier configured to receive the Hall voltages and provide a first output voltage that corresponds to the first positive voltage and the second positive voltage and a second output voltage that corresponds to the first negative voltage and the second negative voltage.

2. The circuit of claim 1, wherein the amplifier comprises:

a first impedance;

a second impedance;

a first pair of differential input transistors; and

a second pair of differential input transistors, wherein the amplifier is configured to selectively provide a first output of the first pair of differential input transistors to each of the first impedance and the second impedance.

3. The circuit of claim 2, wherein the amplifier is configured to selectively provide a second output of the first pair of differential input transistors to each of the first impedance and the second impedance.

4. The circuit of claim 2, wherein the amplifier is configured to selectively provide a second output of the second pair of differential input transistors to each of the first impedance and the second impedance.

5. The circuit of claim 4, wherein the amplifier is configured to selectively couple a first current source that is coupled to the first pair of differential input transistors and a second current source that is coupled to the second pair of differential input transistors.

6. The circuit of claim 2, wherein the first pair of differential input transistors receives the first positive voltage and the first negative voltage.

7. The circuit of claim 2, wherein the first pair of differential input transistors receives the first positive voltage and the second positive voltage.

8. The circuit of claim 1, wherein the amplifier comprises:

a first pair of differential input transistors; and

a second pair of differential input transistors, wherein the amplifier is configured to selectively provide the first positive voltage to each of the first pair of differential input transistors and the second pair of differential input transistors and to selectively provide the first negative voltage to each of the first pair of differential input transistors and the second pair of differential input transistors.

9. The circuit of claim 1, wherein the amplifier is configured to selectively short the Hall voltages of each of the first Hall plate and the second Hall plate.

10. A system, comprising:

Hall plates configured to provide Hall voltages via positive voltage sides and negative voltage sides; and

an amplifier configured to receive the Hall voltages and selectively provide a first output voltage obtained via first currents from first transistors driven by voltages on the positive voltage sides and a second output voltage obtained via second currents from second transistors driven by voltages on one of the positive voltage sides and one of the negative voltage sides.

11. The system of claim 10, wherein the amplifier is configured to provide the first output voltage with the Hall plates in a homogeneous magnetic field and the second output voltage with the Hall plates in a differential magnetic field.

12. The system of claim 10, wherein the amplifier comprises:

a first impedance;

a second impedance; and

a pair of differential input transistors, wherein the amplifier is configured to selectively provide an output of the pair of differential input transistors to each of the first impedance and the second impedance.

13. The system of claim 10, wherein the amplifier comprises:

a first pair of differential input transistors; and

a second pair of differential input transistors, wherein the amplifier is configured to selectively provide a first voltage from one of the positive voltage sides to each of the first pair of differential input transistors and the second pair of differential input transistors and to selectively provide a second voltage from one of the negative voltage sides to each of the first pair of differential input transistors and the second pair of differential input transistors.

14. The system of claim 10, wherein the amplifier is configured to selectively short the Hall voltages of each of the Hall plates.

15. A circuit, comprising:

means for providing Hall voltages via positive voltage sides and negative voltage sides;

means for receiving the Hall voltages; and

means for selectively providing a first output voltage that corresponds to voltages on the positive voltage sides and a second output voltage that corresponds to voltages on one of the positive voltage sides and one of the negative voltage sides.

16. The circuit of claim 15, wherein the means for selectively providing comprises:

means for selectively providing the first output voltage in a homogeneous magnetic field.

17. The circuit of claim 15, wherein the means for selectively providing comprises:

means for selectively providing the second output voltage in a differential magnetic field.

18. A method of testing a circuit, comprising:

providing Hall voltages in a homogeneous magnetic field, comprising;

generating a first positive voltage and a first negative voltage on a first Hall plate; and

generating a second positive voltage and a second negative voltage on a second Hall plate;

receiving the Hall voltages;

providing a first output voltage that corresponds to the first positive voltage and the second positive voltage; and

providing a second output voltage that corresponds to the first negative voltage and the second negative voltage.

19. The method of claim 18, comprising:

switching a first output of a first pair of differential input transistors from a first impedance to a second impedance.

20. The method of claim 19, comprising:

switching a second output of the first pair of differential input transistors from the second impedance to the first impedance.

21. The method of claim 19, comprising:

switching a second output of a second pair of differential input transistors from the second impedance to the first impedance.

22. The method of claim 18, comprises:

switching the first positive voltage from a first pair of differential input transistors to a second pair of differential input transistors; and

switching the first negative voltage from the second pair of differential input transistors to the first pair of differential input transistors.

23. The method of claim 18, comprising:

shorting a first Hall voltage of the first Hall plate; and

shorting a second Hall voltage of the second Hall plate.

24. A method of testing a circuit, comprising:

providing Hall voltages via positive voltage sides and negative voltage sides;

receiving the Hall voltages; and

switching an amplifier from providing a first output voltage that corresponds to voltages on one of the positive voltage sides and one of the negative voltage sides to providing a second output voltage that corresponds to voltages on the positive voltage sides.

25. The method of claim 24, comprising:

providing the second output voltage in a homogeneous magnetic field.