Magnetic field sensor, as well as magnetic field measurement method, power measurement device, and power measurement method using the same

1. A magnetic field sensor comprising:

a magnetic thin film comprising a loop body and an internal thin film provided in the loop body;

a feeder comprising input and output terminals configured to supply element current to the magnetic thin film; and

a detector configured to detect a voltage between ends of the magnetic thin film in a direction perpendicular to a direction of the element current,

wherein the magnetic thin film comprises a magnetic film and is symmetric about the direction of the element current.

2. The magnetic field sensor according to claim 1 , wherein the magnetic thin film has a circular contour.

3. The magnetic field sensor according to claim 1 , wherein the magnetic thin film comprises a square loop body, and wherein the feeder allows the current to flow in a diagonal direction of the square.

4. The magnetic field sensor according to claim 1 , wherein the magnetic thin film has a uniform line width.

5. The magnetic field sensor according to claim 1 , wherein the internal magnetic thin film comprises a magnetic thin film a same material as a of the magnetic thin film.

6. The magnetic field sensor according to claim 1 ,

wherein the internal magnetic thin film comprises a magnetic thin film of a material different from a material of the magnetic thin film.

7. A magnetic field measurement method comprising:

providing a magnetic thin film, the magnetic thin film comprising a loop body and an internal magnetic thin film provided in the loop body;

supplying element current to the magnetic thin film such that a pattern of the magnetic thin film is symmetric about the direction of the element current; and

detecting a voltage between ends of the magnetic thin film in a direction perpendicular to a direction of supplying the element current, thereby measuring a magnetic field intensity.

8. A power measurement device, comprising:

a magnetic field sensor comprising:

a magnetic thin film arranged in parallel to a primary conductor in which AC current flows, the magnetic thin film comprising a loop body and an internal magnetic thin film provided in the loop body;

a feeder connected to the primary conductor, and comprising input and output terminals configured to supply element current to the magnetic thin film through a resistor; and

a detector configured to detect outputs from ends of the magnetic thin film; and

a DC component extractor configured to extract a DC component from an output of the detector.

9. The power measurement device according to claim 8 ,

wherein the magnetic field sensor is provided on the same substrate as that of the DC component extractor.

10. The power measurement device according to claim 9 ,

wherein the magnetic thin film of the magnetic field sensor is provided on the substrate, and

the detector is connected directly to a wiring pattern on the substrate.

11. The power measurement device according to claim 10 ,

wherein the magnetic field sensor comprises:

the magnetic thin film provided on the substrate;

the feeder comprising the input and output terminals configured to supply the element current to the magnetic thin film; and

a detection electrode configured to detect the outputs from the ends of the magnetic thin film,

wherein the wiring pattern is configured by the same conductor layer as the conductor layer of the feeder and the detection electrode.

12. The power measurement device according to claim 11 ,

wherein the magnetic thin film is configured such that a magnetic resistor is symmetric about a direction of the element current.

13. The power measurement device according to claim 8 ,

wherein the magnetic thin film has a magnetization direction identical with a direction of the element current.

14. The power measurement device according to claim 8 ,

wherein the detector is configured in a direction perpendicular to a direction of the element current.

15. The power measurement device according to claim 8 ,

wherein the DC component extractor comprises an integrator configured to integrate an output value every 1/f periods when a commercial frequency is f.

16. The power measurement device according to claim 8 , comprising:

a zero-cross point detector configured to detect a zero-cross point of a primary voltage of the element current,

wherein a drive timing of the DC component extractor is determined according to an output of the zero-cross point detector.

17. The power measurement device according to claim 16 , comprising:

a capacitor connected in parallel to the detector.

18. A power measurement method using the power measurement device according to claim 8 , comprising:

supplying element current to a pattern of a magnetic thin film such that a magnetic resistance is symmetric about a direction of the element current; and

extracting a DC component of an output generated by supply of the element current, thereby taking the extracted DC component as electric power information.

19. The magnetic field measurement method according to claim 7 , wherein the magnetic thin film comprises a square loop body, and

wherein a feeder allows the current to flow in a diagonal direction of the square.

20. The power measurement device according to claim 8 , wherein the magnetic thin film comprises of a square loop body, and

wherein the feeder allows the current to flow in a diagonal direction of the square.