JP3358443B2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for supplying electric power to an electronic device and a power for charging the battery in a non-contact manner to an electronic device containing a battery.

[0002]

2. Description of the Related Art In recent years, miniaturization of parts, high integration of ICs,
Low-voltage, low-power, and high-density packaging make it possible to reduce the size of electronic devices. In addition, due to the smaller size and larger capacity of batteries, power for electronic devices can be supplied by batteries, and cordless electronic devices are becoming common. ing. As a result, mobile phones, video cameras, and the like are being exploded because they can be carried anywhere and there are no restrictions on where they can be used.

[0003] In the future, battery-powered electronic devices will increase more and more, and applications in which rechargeable batteries that are advantageous in terms of economy and resources will be used will be expanded.

[0004] However, a rechargeable battery needs to be charged, and it is common to use a contact system to supply power from a charger to an electronic device with a built-in battery. As time passes, contact failures occur due to wear and oxidation of the contacts. In addition, in order to reduce contact failure, the contact is addressed by stabilizing the contact pressure or the like by gold plating or a spring.

Further, in order to eliminate the above-mentioned disadvantages of the contacts,
Electronic devices using a method of charging an electronic device in a non-contact manner are increasing.

Hereinafter, a conventional non-contact type charging device will be described with reference to FIGS. 5 to 6 (A) to 6 (D).

FIG. 5 is a block circuit diagram of the charging device. FIGS. 6 (A) to 6 (D) show a main part of a first coil,
FIG. 4 is an explanatory diagram illustrating a relationship between second coils.

[0008] In the figure, 5a is a charger case,
Reference numeral 6a denotes an equipment case. The input power supply terminal 1 is connected to the switching element 3 via the first coil 4, and the other end of the switching element 3 is connected to the power supply terminal 1. The switching element 3 is connected to an oscillation control circuit 2 for controlling on / off of the switching element 3.

Next, the configuration of the device will be described together with the operation. When the switching element 3 is turned on, the current flowing from the input power supply terminal 1 to the first coil 4 passes through the charger case 5a as magnetic energy, and The energy is converted into electric energy by the second coil 7 in the device case 6a.

The electron energy converted by the second coil 7 causes a current resonance with the capacitor 11 connected in parallel, and when the switching element 3 is in the ON state, the electric current flows from the capacitor 11 to the second coil 7. By setting the resonance condition of the capacitor 11 and the second coil 7 so that the electric power is supplied, a large electric power is supplied from the output control circuit 8 and the electric power can be taken out from the load 9.

Here, when the load 9 is a battery, the output control circuit 8 controls to receive power at a constant current.

When the switching element 3 is off, the current flowing through the first coil 4 becomes a resonance current with the resonance capacitor 10.

Next, the energy transfer from the first coil 4 to the second coil 7 which is important in the power supply device having the above configuration will be described with reference to FIG.

6A is a top view of the second coil 7, and FIG. 6B is a cross section of the first coil 4, the second coil 7, the equipment case 6a and the charger case 5a. FIG. 6C is a top view of the first coil 4,
FIG. 6D is a flow chart of the magnetic flux of the first and second coils.
In FIG. 6, the current flowing through the first coil 4 wound around the first coil bobbin 4b generates a magnetic flux up and down from the first core 4a of the quadrangular prism of the first coil 4, and the charger case 5a And the second coil bobbin 7b passing through the device case 6a
Gathers on the E-shaped core 7a of the second coil 7 wound around the second coil 7, and generates an electromotive force in the second coil 7.

The distribution of the magnetic field generated by the current flowing through the first coil 4 is equal to the distribution of the first magnetic field as shown in FIG.
A large magnetic field leaks from the side of the coil 4 to the lower portion.

[0016]

However, in the above-mentioned conventional configuration, in order to increase the input of the electronic device 6, the core 7a of the second coil 7 is made larger and the device case in which the second coil 7 is built. 6a had to be enlarged.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a power supply device which is small, inexpensive, and can easily and efficiently transmit energy.

[0018]

In order to solve the above-mentioned problems, a power supply according to the present invention comprises a non-contact power supply,
The cross-sectional area of the tip portion of the central rod portion of the first core attached to the first coil is smaller than that of the other rod portions. By reducing the tip portion, the magnetic flux generated by the first coil is reduced. Is reduced, the magnetic flux linked to the second coil increases, and the electric power generated in the second coil increases, so that it is not necessary to increase the size of the device.

According to the first aspect of the present invention, the top surface of the first core mounted on the first coil and having the center rod portion, and the center rod portion mounted on the second coil are provided. The second with
In the power supply device for transmitting electric power with the top surface of the core facing the top surface, the cross-sectional area of the front end portion of the central rod-shaped portion of the first core is set to the second.
The center rod of the first core is smaller than the other rods. Even if the cross section of the second core on the electronic device side having the second coil is small, the tip of the first core is Since the cross-sectional area can be reduced and the magnetic flux can be concentrated, the power generated on the electronic device side can be increased, and the charger side having the first coil can be shared, and the power supply device can be shared. This makes it possible to reduce the price.

According to a second aspect of the present invention, the sectional shape of the central rod portion of the first core according to the first aspect is an elliptical shape, and the area ratio of the second core is increased to increase energy. This improves the transmission efficiency.

According to a third aspect of the present invention, the winding height of the first coil according to the first aspect is greater than the sum of the winding height of the second coil and the distance between the first and second coils. It is intended to improve the energy transmission efficiency.

According to a fourth aspect of the present invention, the size of the non-facing surface of the first core of the first aspect of the present invention with respect to the second coil is substantially the same as the winding height of the first coil. This prevents the leakage of the magnetic flux and improves the energy transmission efficiency.

According to a fifth aspect of the present invention, the size of the non-facing surface of the second core according to the third aspect with respect to the first coil is substantially the same as the winding height of the second coil. In addition, leakage of magnetic flux is prevented to improve energy transmission efficiency.

According to a sixth aspect of the present invention, the first core of the fourth or fifth aspect is provided with a taper at a peripheral edge of a non-opposing surface of the first core with respect to the second coil. The magnetic flux concentrates on the tapered portion to reduce leakage of magnetic flux, thereby improving efficiency and reducing noise.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. (Embodiment 1) FIG. 1A is a top view of a second coil portion which is a main portion of one embodiment, and FIG. 1B is a diagram showing a first coil portion and a second coil portion which are the main portion. FIG. 1C is a side sectional view showing a state where the coil portions are combined, FIG. 1C is a top view of a first coil portion which is a main portion, and FIG. 1D is another second coil having a different size. FIG. 5 is a side sectional view showing a state where the first coil portion and the first coil portion are combined.

According to FIG. 1, reference numeral 16a denotes an equipment case, 17a denotes a second coil bobbin around which a second coil 17 is wound, and an equipment case 1 together with a second core 17c.
6a. 15a is a charging case,
Reference numeral 14b denotes a first coil bobbin around which the first coil 14 is wound, and a charging case 15a together with the first core 14a.
Is installed inside.

The first and second cores 14a, 17c
As is clear from the figure, the cross section has an elliptical shape, and a taper 14c is formed at the upper end of the first core 14a.
The coil 14 is provided so that the inclination starts from a portion above substantially half of the winding width of the coil 14.

The first core 1 is formed by the taper 14c.
Since the magnetic flux generated in 4a is narrowed down, the magnetic flux linked to the small second coil 17 mounted on the device case 16b of the small electronic device increases as shown in FIG. This is to increase the electromotive force generated in the second coil 17. Therefore, the secondary-side electromotive force is
7 can be increased without increasing the size (without increasing the size of the secondary-side electronic device). From the above, it is not necessary to manufacture the charger (primary side) according to the size of the electronic device.
Can be shared.

The taper 14c has a linear shape, which greatly reduces the inductance L value. However, by forming the taper 14c into a radial shape, it is possible to suppress the reduction in the inductance L value.

Here, the output voltage of the first coil will be described. The energy W of the first coil 14 is W = 1.
/ 2 · LI ² , where the L value is proportional to the area of the core.
Therefore, when a conductive wire is wound around the bobbin 4b of the rectangular core 4a of the conventional first coil 4, the outer periphery of the conductive wire becomes close to a circle, and the space factor of the conductive wire occupying the rectangular bobbin 4b is not good.

However, since the periphery of the core 14c of the first coil 14 shown in FIG. 1 is round, the conductor can be wound along the ellipse. As a result, in the case of the same area coil, a larger core area is obtained in the ellipse, and a larger L value is obtained with the same number of turns.

As a result, the voltage / voltage of the above-described embodiment of FIG.
As with the current output characteristic (VI characteristic) 21, the V
An output larger than that of the I characteristic 20 could be obtained. In FIG. 2, reference numeral 22 denotes an elliptical coil in which the core has no taper, and the output slightly decreases. The output power (efficiency) with respect to the input power is also 3% in the case where the core 14a of the first coil 14 has the taper 14c as compared with the case where the taper is not tapered.
improves.

In order to obtain the same output, the first oval
The second coil 17 and the second coil 17 can be made smaller than a rectangular one, and the oval shape is most suitable for making the device thinner.

(Embodiment 2) FIG. 3 is a side sectional view of a first coil and a second coil which are main parts of another embodiment of the power supply device of the present invention, and is the same as that of Embodiment 1. Portions will be described with the same reference numerals.

According to the figure, reference numeral 24 denotes a first coil, 24b denotes a first coil bobbin for winding the first coil, and 24a denotes a first core. Also, 27
Is a second coil, and 27c is a second core around which the second coil 27 is wound.

The winding height L of the first coil 24 is the second
Of the winding height L1 of the first coil 24 and the distance L2 between the first coil 24 and the second coil 27 (L1 + L2).

Further, the first core 24a and the second core 27
A surface (non-facing surface) different from the surface facing both of them extends to the vicinity of the winding heights L and L1 of the respective windings, and a taper 24c is formed on the periphery of the first core 24a. ing.

As described above, the winding height L of the first coil 24 is made equal to the winding height L1 of the second coil 27 and the first coil 24.
4 is set to be larger than the sum (L1 + L2) of the distance L2 and the distance L2 of the second coil 27, as shown in FIG.
Numeral 3 indicates that it easily reaches the second coil 27.

Further, in the above embodiment, the first core 2
Since the periphery of 4a is formed in a tapered shape, the magnetic flux concentrates on the taper 24c, the leakage of the magnetic flux is reduced, and the efficiency is further improved and the noise is reduced.

Since the first core 24a and the second core 27c, which are magnetic materials, are sintered, they have irregularities, and because they are black, heat dissipation is also good.
Double the output current was obtained.

[0041]

As described above, the power supply device of the present invention has the first
Since the cross-sectional area of the front end portion of the center bar portion of the first core mounted on the first coil is smaller than that of the other bar portions, the magnetic flux is narrowed down and the power efficiency can be improved.

[Brief description of the drawings]

FIG. 1A is a top view of a second coil which is a main part of an embodiment of the power supply device of the present invention. FIG. 1B is a side of a state where the first and second coils which are the main part are combined. Sectional view (C) Top view of the first coil which is the main part (D) Side sectional view of a state where the first coil is combined with another second coil having different sizes.

FIG. 2 is a graph showing the same voltage and current output characteristics.

FIG. 3 is a side sectional view showing a state where a first coil and a second coil which are main parts of the other embodiment are combined.

FIG. 4 is an explanatory view of the flow of the magnetic flux.

FIG. 5 is a block circuit diagram of a conventional charging device.

6A is a top view of the second coil, FIG. 6B is a side cross-sectional view of a state where the first and second coils are combined, FIG. 6C is a top view of the first coil, and FIG. Illustration of the flow of

[Explanation of symbols]

 14 first coil 14a first core 14c taper 17, 27 second coil 17c second core 24 first coil 24c taper

Claims (6)

(57) [Claims] A first rod-shaped portion attached to the first coil;
The top surface of the first core and the center attached to the second coil
In a power supply device for transmitting electric power by facing a top surface of a second core having a rod-shaped portion, a cross-sectional area of a tip portion of a center rod-shaped portion of the first core may be different from that of a center rod-shaped portion of the first core . A power supply unit smaller than the bar. 2. The power supply device according to claim 1, wherein the cross section of the front end of the central rod portion of the first core is an oval, and has a smaller sectional area than the other rod portions. 3. The winding height of the first coil is adjusted to the second winding height.
2. The power supply unit according to claim 1, wherein the height of the coil is larger than the sum of the distance between the first and second coils. 4. The method according to claim 1, wherein a size of a non-facing surface of the first core mounted on the wound first coil with respect to the second coil is substantially equal to a winding height of the first coil. Item 2. The power supply device according to Item 1. 5. The size of a non-facing surface of the second core mounted on the wound second coil and facing the first coil is set to the second coil.
5. The power supply device according to claim 4, wherein the winding height of the coil is substantially the same. 6. The power supply device according to claim 4, wherein a taper is provided on a peripheral edge of a surface of the first core that is not opposed to the second coil.