Charging apparatus for an electronic device

• US 4,873,677 A
• Filed: 07/07/1988
• Issued: 10/10/1989
• Est. Priority Date: 07/10/1987
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Sakamoto, Kenji, Hayakawa, Motomu, Ishikawa, Nobuo
• Primary Examiner(s): Miska, Vit W.
• Application Number:
  US07/216,914
• Time in Patent Office: 460 Days
• Field of Search: 368/64, 368/66, 368/203-205, 320/2, 320/21, 320/61
• US Class Current: 368/204
• CPC Class Codes: G04C 10/00 Arrangements of electric power supplies in time pieces circuits G04G19/00; mounting, assembling of components of electromechanical watches G04C3/008, of electronic watches G04G17/00
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction

Abstract

An apparatus for charging a power storage device provided within an electronic device. A power source provides direct current which is alternated in direction through a pair of primary coils for inducing alternating current in a secondary coil of the electronic device. The pair of primary coils are fixed to a coil yoke all of which are supported within a casing of the apparatus. During charging of the power storage device, the electronic device is mounted to the outside surface of the casing whereby substantially all of the magnetic flux of the magnetic field produced by the pair of primary coils flows through the secondary coil and coil yoke. The frequency of the oscillating signal is preset to provide the maximum induced current which will not adversely affect the movement of the analog mechanisms within the electronic device.

Claims

1. An apparatus for charging a power storage device provided within an electronic device which also includes at least one secondary coil, said apparatus comprising:

a power source for producing direct current;

a pair of primary coils for generating a magnetic field which passes through the at least one secondary coil and for inducing alternating current in the at least one secondary coil of the electronic apparatus;

a coil yoke for positioning the primary coils relative to each other;

oscillating means for generating an oscillating signal;

switching means for alternating the direction of the direct current flowing through the primary coils in response to the oscillating signal; and

a case member including mounting means for receiving and holding the electronic device, said case member supportng the pair of primary coils and the coil yoke at a predetermined distance relative to the mounting means whereby during charging of the power storage device substantially all of the magnetic flux of the magnetic field generated by primary coils flows through the coil yoke and at least one secondary coil in the electronic device.

2. The apparatus of claim 1, wherein the pair of primary coils resemble a pair of substantially triangular shaped rings.

3. The apparatus of claim 2, wherein the pair of primary coils include metallic cores.

4. The apparatus of claim 3, wherein the metallic cores are made of malleable iron.

5. The apparatus of claim 4, wherein the coil yoke has a substrate selected from the group of materials consisting of glass epoxy and plastic.

6. The apparatus of claim 5, wherein the coil yoke is made of a magnetic permeable material.

7. The apparatus of claim 1, wherein the coil yoke is a substantially rectangular plate on which the pair of primary coils are fixed.

8. The apparatus of claim 7, wherein the coil yoke is made of a magnetic permeable material.

9. The apparatus of claim 1, wherein the pair of primary coils are connected electrically in series.

10. The apparatus of claim 1, wherein the pair of primary coils have substantially triangular contours and are disposed adjacent to each other along a planar surface of the coil yoke.

11. The apparatus of claim 10, wherein the pair of primary coils are connected electrically in series.

12. The apparatus of claim 1, wherein the pair of primary coils, when energized, have opposite polarities.

13. The apparatus of claim 1, wherein the power storage device is a battery.

14. The apparatus of claim 1, wherein the electronic device is a timepiece.

15. The apparatus of claim 14, wherein the timepiece is a wristwatch.

16. The apparatus of claim 1, wherein the switching means includes four pairs of transistors connected electrically together to form a parallel circuit, two pair of said four pairs of transistors forming a first branch and the other two pairs of transistors forming a second branch of the electrically parallel circuit.

17. The apparatus of claim 16, wherein the pair of primary coils are connected electrically in series wih one end of the pair of primary coils electrically connected between said two pair of said four pairs of transistors and with the other end of the pair of primary coils electrically connected between the other two pairs of transistors.

18. The apparatus of claim 1, wherein the oscillating circuit includes a Schmidtt trigger.

19. The apparatus of claim 1, further including timing means for controlling the length of time during which the oscillating signal is provided to the switching means.

20. The apparatus of claim 19, wherein the timing means includes at least one resistor and at least one capacitor forming a predetermined RC time constant.

21. The apparatus of claim 1, wherein the electronic device further includes a motor having a rotor and wherein oscillating means includes adjusting means for presetting the frequency of the oscillating signal to avoid adversely affecting operation of the rotor.

22. The apparatus of claim 21, wherein the rotor is a permanent magent.

23. The apparatus of claim 21, wherein the adjusting means is operable for presetting the frequency of the oscillating signal above 200 hertz.

24. The apparatus of claim 23, wherein the adjusting means is operable for presetting the frequency of the oscillating signal to approximately 1,000 hertz.

25. The apparatus of claim 21, wherein the pair of primary coils resemble a pair of substantially triangular shaped rings.

26. The apparatus of claim 25, wherein the pair of primary coils include metallic cores.

27. The apparatus of claim 26, wherein the metallic cores are made of malleable iron.

28. The apparatus of claim 27, wherein the coil yoke has a substrate selected from the group of materials consisting of glass epoxy and plastic.

29. The apparatus of claim 28, wherein the coil yoke is made of a magnetic permeable material.

30. The apparatus of claim 21, wherein the coil yoke is a substantially rectangular plate on which the pair of primary coils are fixed.

31. The apparatus of claim 21, wherein the coil yoke is made of a magnetic permeable material.

32. The apparatus of claim 21, wherein the pair of primary coils are connected electrically in series.

33. The apparatus of claim 32, wherein the pair of primary coils have substantially triangular contours and disposed adjacent to each other along a planar surface of the coil yoke.

34. The apparatus of claim 21, wherein the pair of primary coils, when energized, have opposite polarities.

35. An apparatus for charging a power storage device provided within an electronic device which also includes at least one secondary coil and a motor having a rotor, said apparatus comprising:

a power source for producing direct current;

a pair of primary coils electrically connected in series resembling a pair of substantially triangular shaped rings for generating a magnetic field which passes through the at least one secondary coil and for inducing alternating current in the at least one secondary coil of the electronic apparatus;

a coil yoke made of a magnetic permeable material and having a substantially rectangular shape for positioning the primary coils relative to each other;

oscillating means for generating an oscillating signal and including adjusting means for setting the frequency of the oscillating signal to a predetermined level to avoid adversely affecting operation of the rotor;

switching means for alternating the direction of the direct current flowing through the primary coils in response to the oscillating signal and including four pairs of transistors connected electrically together to form a parallel circuit, a first two of said four pairs of transistors forming a first branch and a second two of said four pairs of transistors forming a second branch of the parallel circuit with one end of the pair of primary coils connected between the first two of said four pairs of transistors and with the other end of the pair of primary coils connected between the second two of said four pairs of transistors; and

a case member including mounting means for receiving and holding the electronic device, said case member supporting the pair of primary coils and the coil yoke at a predetermined distance relative to the mounting means whereby during charging of the power storage device substantially all of the magnetic flux of the magnetic field flows through the at least one secondary coil and the coil yoke.

36. A method for charging a power storage device provided within an electronic device which also includes at least one secondary coil, said method comprising:

placing the electronic device at a predetermined position on a surface of a casing of a charging apparatus with the at least one secondary coil near said surface;

positioning a pair of primary coils and a coil yoke at a predetermined position within the casing;

generating an oscillating signal; and

switching the direction of direct current flow through the primary coils in response to the oscillating signal so as to induce an alternating current in the at least one secondary coil for charging the power storage device whereby during charging of the power storage device substantially all of the magnetic flux of the magnetic field produced by the pair of primary coils flows through at least one secondary coil and the coil yoke.