Electromagnetic coupling characteristic adjustment method in non-contact power supply system, power supply device, and non-contact power supply system

• US 20040095291A1
• Filed: 11/12/2003
• Published: 05/20/2004
• Est. Priority Date: 11/12/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shigemasa, Haruhiko, Nakao, Yoshihiro
• Granted Patent: US 6,889,905 B2
• Time in Patent Office: Days
• US Class Current: 343/913
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

An electromagnetic coupling characteristic adjustment method for adjusting an electromagnetic coupling characteristic between a reader/writer device and an IC card which are used in a non-contact communication system in which a power transmission antenna coil provided in the reader/writer device and a power receiving antenna coil provided in the IC card are electromagnetically coupled so that the reader/writer device supplies power to the IC card without contact with the IC card. The power supply device includes adjustment impedance elements respectively connected in series and in parallel with the power transmission antenna coil. Impedances of these adjustment impedance elements are determined so that the semiconductor device receives greatest power when a power supply distance, which is a distance between the power transmission antenna coil and the power receiving antenna coil, has a predetermined value not less than 0. On this account, heat generation due to the difference of received power can be reduced with a simple structure.

Claims

1. An electromagnetic coupling characteristic adjustment method for adjusting an electromagnetic coupling characteristic between a power supply device and a semiconductor device which are used in a non-contact power supply system in which a power transmission antenna coil provided in the power supply device and a power receiving antenna coil provided in the semiconductor device are electromagnetically coupled so that the power supply device supplies power to the semiconductor device without contact with the semiconductor device,

the power supply device including a first adjustment impedance element connected in series to the power transmission antenna coil and a second adjustment impedance element connected in parallel with the power transmission antenna coil,

the electromagnetic coupling characteristic adjustment method comprising the step of:

(a) determining impedances of the first and second adjustment impedance elements so that the semiconductor device receives greatest power when a power supply distance, which is a distance between the power transmission antenna coil and the power receiving antenna coil, has a predetermined value not less than 0.

2. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 1, wherein,

the step (a) includes the sub-steps of:

determining a relation between (i) an electromagnetic coupling coefficient for the power transmission antenna coil and the power receiving antenna coil, and (ii) the power supply distance; and

determining impedances of the first and second adjustment impedance elements so that the semiconductor device receives the greatest power when an electromagnetic coupling coefficient becomes a value corresponding to the predetermined value of the power supply distance.

3. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 1, further comprising the step of:

(b) determining power supplied from the power supply device so that the semiconductor device receives greater power than a minimum power for operation of the semiconductor device when the power supply distance is within a predetermined range.

4. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 1, wherein:

the first and second adjustment impedance elements are capacitors.

5. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 4, wherein:

the step (a) is performed to determine capacitances of the first and second adjustment impedance elements so that the semiconductor device receives the greatest power when the power supply distance has the predetermined value not less than 0.

6. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 1, wherein:

the predetermined value is in a range from 20 mm to 40 mm.

7. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 1, wherein:

the semiconductor device is an IC card.

8. An electromagnetic coupling characteristic adjustment method for adjusting an electromagnetic coupling characteristic between a power supply device and a semiconductor device which are used in a non-contact power supply system in which a power transmission antenna coil provided in the power supply device and a power receiving antenna coil provided in the semiconductor device are electromagnetically coupled so that the power supply device supplies power to the semiconductor device without contact with the semiconductor device,

the power supply device including a first adjustment impedance element connected in series to the power transmission antenna coil and a second adjustment impedance element connected in parallel with the power transmission antenna coil,

the electromagnetic coupling characteristic adjustment method comprising the step of:

(a) determining impedances of the first and second adjustment impedance elements so that the semiconductor device receives greater power than a minimum power for operation of the semiconductor device when a power supply distance, which is a distance between the power transmission antenna coil and the power receiving antenna coil, is within a predetermined range.

9. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 8, wherein,

the step (a) includes the sub-steps of:

determining a relation between (i) an electromagnetic coupling coefficient for the power transmission antenna coil and the power receiving antenna coil, and (ii) the power supply distance; and

determining impedances of the first and second adjustment impedance elements so that the semiconductor device receives the greater power than a minimum power for operation of the semiconductor device when an electromagnetic coupling coefficient becomes a value corresponding to the predetermined range of the power supply distance.

10. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 8, wherein:

the first and second adjustment impedance elements are capacitors.

11. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 10, wherein:

the step (a) is performed to determine capacitances of the first and second adjustment impedance elements so that the semiconductor device receives the greater power than a minimum power for operation of the semiconductor device when the power supply distance is within a predetermined range.

12. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 8, wherein:

the predetermined range has a lower limit of 0.

13. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 8, wherein:

the predetermined range has a lower limit greater than 0.

14. The electromagnetic coupling characteristic adjustment method in a non-contact power supply system as set forth in claim 8, wherein:

the semiconductor device is an IC card.

15. A power supply device including a power transmission antenna coil which is electromagnetically coupled with a power receiving antenna coil provided in a semiconductor device so as to supply power to the semiconductor device without contact with the semiconductor device, comprising:

a first adjustment impedance element connected in series to the power transmission antenna coil; and

a second adjustment impedance element connected in parallel with the power transmission antenna coil,

impedances of the first and second adjustment impedance elements being determined so that the semiconductor device receives greatest power when a power supply distance, which is a distance between the power transmission antenna coil and the power receiving antenna coil, is within a predetermined range whose lower limit is greater than 0.

16. The power supply device as set forth in claim 15, further comprising:

a power supply section for supplying power to the power transmission antenna coil, the power supplied to the power transmission antenna coil is determined so that the semiconductor device receives greater power than a minimum power for operation of the semiconductor device when the power supply distance is within the predetermined range.

17. The power supply device as set forth in claim 15, wherein:

the first and second adjustment impedance elements are capacitors.

18. The power supply device as set forth in claim 17, wherein:

impedances of the first and second adjustment impedance elements are determined so that the semiconductor device receives the greatest power when the power supply distance is within a predetermined range whose lower limit is greater than 0.

19. A non-contact power supply system including a power supply device and a semiconductor device having a power receiving antenna coil which is electromagnetically coupled with a power transmission antenna coil of the power supply device so as to supply power from the power supply device to the semiconductor device without contact therebetween,

the power supply device including a first adjustment impedance element connected in series to the power transmission antenna coil and a second adjustment impedance element connected in parallel with the power transmission antenna coil,

impedances of the first and second adjustment impedance elements being determined so that the semiconductor device receives greatest power when a power supply distance, which is a distance between the power transmission antenna coil and the power receiving antenna coil, is within a predetermined range whose lower limit is greater than 0.

20. The non-contact power supply system as set forth in claim 19, wherein:

the first and second adjustment impedance elements are capacitors.

21. The non-contact power supply system as set forth in claim 20, wherein:

capacitances of the first and second adjustment impedance elements are determined so that the semiconductor device receives the greatest power when the power supply distance is within the predetermined range.

22. The non-contact power supply system as set forth in claim 19, wherein:

the semiconductor device is an IC card.