JPH10189369A - Non-contact-type power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable Hartley oscillator to be used as the high-frequency oscillation circuit of a charging part, reduce the number of parts and cost, and at the same time reduce loss and hence improve a power transmission efficiency in a non-contact-type power transmission device. SOLUTION: In a power transmission device, a charging part and a part to be charged are constituted while they are detachably separated, the charging part has a transmission coil 25 and a high-frequency oscillation circuit, the part to be charged has a reception coil 26, and power is transmitted without any contact from the charging part to the part to be charged. In this case, the high-frequency oscillation circuit is composed of Hartley oscillator including a coil 27 for oscillation and the transmission coil 25, the oscillation coil 27 and the transmission coil 25 are composed of separated, independent coil parts, at the same time at least one portion of the oscillation coil 27 is located in an inner region S of the coil winding part of the transmission coil 25, and both coils are arranged in an electromagnetically connectable state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type portable telephone, a PHS telephone (simplified portable telephone), a cordless phone, various electric devices, and an electronic device which operate using a rechargeable secondary battery as a power supply. The present invention relates to a power transmission device. In particular, the present invention relates to a non-contact power transmission device that transmits electric power from a charged part to a charged part by electromagnetic induction without contacting a metal contact.

[0002]

2. Description of the Related Art A conventional example will be described below with reference to the drawings. §1: Description of a non-contact type power transmission device—see FIG. 13 FIG. 13 is an explanatory diagram (part 1) of a conventional example, where A is a configuration diagram of a charging unit and a charged unit, and B is a charging state explanatory diagram. It is. Conventionally, the charging part and the part to be charged are detachably separated and configured,
The charging unit includes a power transmission coil, a high-frequency oscillation circuit for driving the power transmission coil, a power reception coil for electromagnetically coupling the power transmission coil to the power receiving unit to induce a voltage, and an induction coil for the power reception coil. Charge with the voltage 2
There has been known a non-contact power transmission device that includes a secondary battery or the like and transmits power from the power transmission unit to the power reception unit by electromagnetic induction without contact via a metal contact.

FIG. 13A shows an example (coil portion) of the non-contact type power transmission device. As shown in FIG. 13A, the charging unit and the charged unit are configured to be detachably separated,
The charging section is provided with a power transmission coil 7 wound around a power transmission coil bobbin 6 and a feedback coil 8. In this case, the power transmission coil 7 and the feedback coil 8 are wound around one power transmission coil bobbin 6 and are arranged coaxially. A core 9 is inserted into the power transmission coil bobbin 6.

[0004] A driving circuit 13 is provided in the charging section for driving the power transmission coil 7.
Has a power supply circuit and the high-frequency oscillation circuit, and is configured to drive the power transmission coil 7 by the high-frequency oscillation circuit. On the other hand, the bobbin 11 for the power receiving coil
Is provided with a power receiving coil 12 wound around.

[0005] When charging the secondary battery in the charged part, the charged part is placed on the charging part as shown in FIG. 13B. In this case, a concave portion for mounting the charged portion is formed in a part of the charging portion side case 3, and the charged portion is mounted on the concave portion.

In this state, the power transmitting coil 7 and the power receiving coil 1
2 are arranged opposite to each other, are in the closest state, and are in a charge standby state. Thereafter, when the power supply of the charging unit is turned on to operate the driving circuit 13 and the power transmission coil 7 is driven by the high-frequency oscillation circuit, the charging unit does not contact the charged unit without contacting the metal contact, and the electromagnetic induction acts. The power is transmitted, and the rechargeable battery is charged using the power.

§2: Description of the high-frequency oscillation circuit ... FIG.
Reference FIG. 14 is an explanatory diagram (part 2) of a conventional example, in which A is an oscillation principle diagram, and B is a Hartley oscillation circuit. The drive circuit 1
As the high-frequency oscillation circuit provided in 3, for example, a push-pull high-frequency oscillation circuit using two transistors and an LC parallel resonance circuit including the power transmission coil 7 has been used. The circuit has a large number of components. Therefore, it has been considered to use a Hartley oscillation circuit having the least number of components among the LC oscillation circuits.

Generally, the principle of oscillation shown in FIG.
At the impedance Z₁, Z _Two, Z_ThreeThree elements
And the transistor Q1 as an amplifying element
If connected, impedance Z₁Element of induction
Element (or capacitive element) with impedance Z_Two, Z
_ThreeIf the element is a capacitive element (or inductive element),
It is known that the oscillation condition can be maintained
I have.

A Hartley oscillation circuit can be constructed by using a capacitive element as the element having the impedance Z _{1 and} an inductive element as the element having the impedances Z ₂ and Z ₃ and connecting the respective elements to the transistor Q 1.
Such a Hartley oscillation circuit (self-excited oscillation circuit) is shown in FIG. The Hartley oscillation circuit includes a first coil T1, a second coil T2, and a capacitor C1.
And the transistor Q1, and the number of parts can be reduced. However, it has been difficult to use the Hartley oscillation circuit as it is as the high-frequency oscillation circuit of the charging section. Hereinafter, the reason will be described.

In order to constitute the high-frequency oscillation circuit of the charging section with a Hartley oscillation circuit, the power transmission coil 7 is a first coil T1, and the feedback coil 8 is a second coil T2.
(Oscillation coil). In this case, the first coil T1 is used by being electromagnetically coupled to the second coil T2, and the voltage generated in the second coil T2 by electromagnetic induction is applied to the base of the transistor Q1 (applied as a reverse bias). .

However, if the voltage generated in the second coil T2 is larger than a specified value, an excessive voltage is applied to the base of the transistor Q1, which may destroy the transistor Q1. If the voltage generated in the second coil T2 is smaller than the specified value, an appropriate voltage is not applied to the base of the transistor Q1, and the loss increases. That is, the transistor Q1
When an appropriate positive feedback voltage is applied to the base, the oscillation operation with less loss is performed, but when the positive feedback voltage is small, the loss increases.

Therefore, it is necessary to properly adjust the bias of the transistor Q1, but in the conventional coil arrangement, as shown in FIG. 13, the two coils (T1, T1)
2) is wound around the same coil bobbin and fixedly arranged coaxially, so that the degree of electromagnetic coupling between the first coil T1 and the second coil T2 cannot be adjusted.

Further, a first coil T1 and a second coil T
In order to adjust the degree of electromagnetic coupling with the second coil T2, it is conceivable to change the number of turns of the second coil T2. However, changing the number of turns changes the self-inductance value of the second coil T2. In the Hartley oscillation circuit, the first coil T1 and the second coil T1
The oscillation condition is satisfied when the self-inductance value of the coil T2 is a certain value.
When the self-inductance value is changed by changing the number of turns of
The oscillation condition is not satisfied, and the oscillation operation cannot be performed. Therefore, it is difficult to adjust the bias of the transistor Q1 to an appropriate value, and it is difficult to configure the high-frequency oscillation circuit with a Hartley oscillation circuit.

[0014]

The above-mentioned conventional apparatus has the following problems. (1): Since the Hartley oscillation circuit requires the least number of components among the LC oscillation circuits, it has been considered to use a Hartley oscillation circuit as the high-frequency oscillation circuit of the charging section. However, it has been difficult to use the Hartley oscillation circuit as it is as a conventionally known high frequency oscillation circuit of the charging unit.

That is, in order to configure the high-frequency oscillation circuit of the charging unit with a Hartley oscillation circuit, the power transmission coil 7
Is used as the first coil T1, and the feedback coil 8 is used as the second coil T2 (oscillation coil). In this case, the first coil T1 is used by being electromagnetically coupled to the second coil T2.
Is applied to the base of the transistor Q1.

If the voltage generated in the second coil T2 is larger than a specified value, an excessive voltage is applied to the base of the transistor Q1, which may destroy the transistor Q1. On the other hand, if the voltage generated in the second coil T2 is smaller than the specified value, an appropriate voltage is not applied to the transistor Q1, and the loss increases. That is, when an appropriate positive feedback voltage is applied to the base of the transistor Q1, an oscillation operation with a small loss is performed, but when the positive feedback voltage is small, the loss increases.

Therefore, it is necessary to appropriately adjust the bias of the transistor Q1. However, in the conventional coil arrangement, the two coils are wound around the same coil bobbin and fixedly arranged coaxially. The degree of electromagnetic coupling between the coil T1 and the second coil T2 cannot be adjusted. Therefore, it is difficult to adjust the base voltage of the transistor Q1 to an appropriate value, and it is difficult to use the Hartley oscillation circuit as it is as the high-frequency oscillation circuit.

(2): In the conventional coil arrangement,
In order to adjust the degree of electromagnetic coupling between the first coil T1 and the second coil T2, it is conceivable to change the number of turns of the second coil T2.
2 changes the self-inductance value.

However, in the Hartley oscillation circuit, the first
When the self-inductance value of the second coil T2 satisfies the oscillation condition when the self-inductance value of the coil T1 and the second coil T2 is a certain value, the self-inductance value is changed by changing the number of turns of the second coil T2 as described above. The condition is not satisfied, and the oscillation operation cannot be performed. Thus, the transistor Q1
Since it is difficult to adjust the bias to a proper value, it is difficult to use the Hartley oscillation circuit as it is as the high-frequency oscillation circuit.

(3) As described above, since it is difficult to use the Hartley oscillation circuit as it is as a conventionally known high-frequency oscillation circuit of the charging unit, it is difficult to reduce the number of parts, and it is difficult to reduce the number of parts. It was difficult to achieve low cost.

The present invention solves such a conventional problem and makes it possible to adjust the induced voltage of a coil for applying a reverse bias to the base of a transistor, thereby using a Hartley oscillation circuit as a high-frequency oscillation circuit of a charging unit. It is an object of the present invention to reduce the number of components and cost, to reduce the loss by always adjusting the reverse bias of the transistor to an optimum value, and to improve the power transmission efficiency.

[0022]

FIG. 1 is a view for explaining the principle of the present invention, wherein A is a circuit diagram, B is a coil arrangement example 1, and C is a coil arrangement example 2. FIG. In FIG. 1, Q1 is a transistor, R1 is a resistor, C1, C2, C3, and C4 are capacitors, 25 is a power transmission coil, 27 is an oscillation coil, 26 is a power reception coil, d1 is a diode, and 22 is a secondary battery.
Further, a transistor Q1, a resistor R1, a capacitor C1,
A Hartley oscillation circuit is configured by C2, the power transmission coil 25, and the oscillation coil 27.

According to the present invention, in order to achieve the above object, as shown in FIG. 1, a charging section and a charged section are detachably separated from each other, and the charging section includes a power transmission coil 25 and the power transmission coil. A high-frequency oscillation circuit for driving the coil 25; a power receiving coil 26 for electromagnetically coupling with the power transmission coil 25 to induce a voltage in the charged part; In the non-contact type power transmission device for transmitting power in the above, the high-frequency oscillation circuit is constituted by a Hartley oscillation circuit including an oscillation coil 27 and the power transmission coil 25, and the power transmission coil 25 and the oscillation coil 27
Is the oscillation coil 27 with respect to the winding surface of the power transmission coil 25.
Are arranged so that the winding surfaces thereof are parallel to each other, and at least a part of the oscillation coil 27 is
Are located in the inner region S of the winding portion, and both coils are arranged so as to be capable of electromagnetic coupling.

Further, according to the present invention, the charging section and the charged section are detachably separated from each other.
A high-frequency oscillation circuit for driving the power transmission coil 25; a power receiving coil 26 for electromagnetically coupling with the power transmission coil 25 to induce a voltage; In a non-contact power transmission device for transmitting power to a unit in a non-contact manner, the high-frequency oscillation circuit includes a Hartley oscillation circuit including an oscillation coil 27 and the power transmission coil 25, and the power transmission coil 25 and the oscillation coil 27 is arranged so that the winding surface of the oscillation coil 27 is perpendicular to the winding surface of the power transmission coil 25, and at least a part of the oscillation coil 27 is The two coils were located in a region and were placed in a state where the two coils could be electromagnetically coupled.

(Operation) The operation of the present invention based on the above configuration will be described with reference to FIG. First, when manufacturing the components of the charging unit, the oscillation coil 27 and the power transmission coil 25 are manufactured as separate and independent coil components. Thereafter, the coil unit is manufactured by positioning and mounting the power transmission coil 25 and the oscillation coil 27 on, for example, a printed circuit board, and at least a part of the oscillation coil 27 is formed in an inner region of the winding part of the power transmission coil 25. S, and both coils are arranged so as to be capable of electromagnetic coupling.

In this case, as shown in FIG. 1B, the oscillation coil 27 is connected to the inner region S of the winding portion of the power transmission coil 25.
In the center of the inside, or as shown in FIG. 1C,
While positioning the oscillation coil 27 at one corner (one corner on both sides) in the inner region S of the winding portion of the power transmission coil 25, or moving the oscillation coil 27 to an arbitrary position intermediate between the above positions, the position of the oscillation coil 27 is changed. Is adjusted, the transistor Q1
Is set so that the optimum reverse bias is always applied to the.

A coil unit in which the oscillation coil 27 is set at an optimum position with respect to the power transmission coil 25 in this manner.
And other components are incorporated in the charging section, and components such as the power receiving coil 26 and the secondary battery 22 are also incorporated in the charged section. When a part to be charged is placed at a predetermined position on the charging part manufactured as described above and the power is turned on to the charging part, a high-frequency oscillation circuit including a Hartley oscillation circuit performs an oscillating operation.

By driving the power transmission coil 25 by the Hartley oscillation circuit as described above, high-frequency electromagnetic waves are generated, and non-contact power transmission by electromagnetic waves to the charged part is performed. At this time, an induced voltage is generated in the power receiving coil 26 by the electromagnetic induction effect from the power transmitting coil 25 in the charged part. This induced voltage causes the receiving coil 26 and the capacitor C
3 is in resonance, and the amplitude of the received voltage is increased. Then, the DC voltage that has been half-wave rectified by the diode d1 and smoothed by the capacitor C4 is applied to the secondary battery 22 as a load, and the secondary battery 22 is charged.

As described above, the Hartley oscillation circuit can be used as the high-frequency oscillation circuit of the charging unit by adjusting the induced voltage of the oscillation coil 27 for applying a reverse bias to the base of the transistor Q1. For this reason, the number of parts can be reduced, the cost can be reduced, and the reverse bias of the transistor can always be adjusted to an optimum value, so that loss can be reduced and power transmission efficiency can be improved.

The power transmission coil 25 and the oscillation coil 27
Are arranged so that the winding surface of the oscillation coil 27 is perpendicular to the winding surface of the power transmission coil 25, and at least a part of the oscillation coil 27 is located within the winding area of the power transmission coil 25. In the same manner as above, the transistor Q1
Since the induced voltage of the oscillation coil 27 for applying a reverse bias to the base of the charging unit can be adjusted, a Hartley oscillation circuit can be used as the high-frequency oscillation circuit of the charging unit.

Therefore, also in this case, the number of parts is reduced,
Since the cost can be reduced and the reverse bias of the transistor can always be adjusted to an optimum value, loss can be reduced and power transmission efficiency can be improved.

[0032]

Embodiments of the present invention will be described below in detail with reference to the drawings. §1: Description of a specific example of a non-contact type power transmission device ... FIG.
Reference FIG. 2 is a configuration diagram of a cordless phone.
Is a partially enlarged view (an enlarged view of a part A shown in A).
The non-contact power transmission device according to the present invention can be applied to, for example, a cordless phone as shown in FIG. This cordless phone includes a charger 20 and a cordless phone handset 21. A power transmission coil 25, a high-frequency oscillation circuit for driving the power transmission coil 25, and a rectifying /
A power supply circuit including a smoothing circuit 28 and a fuse 29 is provided. A power plug 30 is connected to the power circuit.

On the other hand, in a cordless phone handset case 23 constituting the cordless phone handset 21, a power receiving coil 26 for electromagnetically coupling with the power transmitting coil 25 to induce a voltage, and a voltage induced in the power receiving coil 26 A secondary battery 22 or the like to be charged is provided.

[0034] When charging the secondary battery 22, connect the power plug 30 to a commercial power supply _{(50 / 60H Z, 100V)} , place the cordless handset 21 in a predetermined position on the charger 20. In this state, when the high-frequency oscillation circuit in the charger 20 starts the oscillating operation, power is transmitted from the power transmission coil 25 to the power reception coil 26 in a non-contact manner without passing through a metal contact. At this time, a voltage is induced in the power receiving coil 26 on the cordless phone handset 21 side, and the voltage induces the secondary battery 22.
Charge. In the following description, the charger 20 is also referred to as a “charging unit”, and the cordless phone handset is also referred to as a “charged unit”.

§2: Description of the high-frequency oscillation circuit—see FIG. 3 FIG. 3 is a circuit diagram. The circuit shown in FIG. 3 is a circuit of the charger 20 (charging unit) and the cordless phone handset 21 (charged unit) shown in FIG. The charging unit and the charged unit are configured to be detachably separated from each other, and the charging unit includes a power transmission coil 25, a high-frequency oscillation circuit for driving the power transmission coil, and a power supply circuit. Power plug 3
0 is connected.

The power supply circuit includes a rectifying / smoothing circuit 28 and a fuse 29. An AC voltage input via a power plug 30 is input to the rectifying / smoothing circuit 28. In this case, the rectification / smoothing circuit 28 performs a rectification / smoothing operation based on the input AC voltage and outputs a DC voltage. Then, the high frequency oscillation circuit operates using the output of the rectification / smoothing circuit 28 as a power supply.

The high-frequency oscillation circuit includes a transistor Q1, a power transmission coil 25, and an oscillation coil 27.
, A Hartley oscillation circuit composed of capacitors C1 and C2 and a resistor R1, and the power transmission coil 25 is driven by the Hartley oscillation circuit. In the Hartley oscillation circuit, the power transmission coil 2
5. The oscillation coil 27 is the first coil shown in FIG.
Correspond to the second coil 27 and the second coil 27. The resistor R1 is a resistor for supplying a DC bias current to the base of the transistor Q1, and the capacitor C2 is for preventing a DC current from flowing from the power supply to the ground via the resistor R1 and the oscillation coil 27. It is a capacitor.

On the other hand, a power receiving coil 26 for electromagnetically coupling with the power transmitting coil 25 to induce a voltage and a capacitor C3 (parallel connected to the power receiving coil 26 and constituting a parallel resonance circuit) A parallel resonance capacitor), a rectifying diode d1, a smoothing capacitor C4, and a secondary battery 22 are provided.

By driving the power transmission coil 25 by the Hartley oscillation circuit, a high-frequency electromagnetic wave is generated, and non-contact power transmission by electromagnetic waves to the charged portion is performed. In this case, in the charged part, an induced voltage is generated in the power receiving coil 26 by the electromagnetic induction effect from the transmitting coil 25. This voltage causes the parallel resonance circuit including the power receiving coil 26 and the capacitor C3 to be in a resonance state, thereby increasing the amplitude of the received voltage. Then, the DC voltage that has been half-wave rectified by the diode d1 and smoothed by the capacitor C4 is loaded into the load 2
The voltage is applied to the secondary battery 22 to charge the secondary battery 22.

§3: Description of coil arrangement relationship... FIG.
FIG. 4 is a diagram illustrating an example of coil arrangement. FIG. 4A illustrates Example 1, B illustrates Example 2, C illustrates Example 3, and D illustrates Example 4. Hereinafter, an arrangement relationship between the power transmission coil 25 and the oscillation coil 27 provided in the charging unit will be described with reference to FIG. As described in the conventional example, in order to be able to use the Hartley oscillation circuit as the high-frequency oscillation circuit of the charging unit, it is necessary to adjust the degree of electromagnetic coupling between the power transmission coil 25 and the oscillation coil 27. is there.

Therefore, the power transmission coil 25 and the oscillation coil 2
7 is composed of separate and independent coil parts, and at least a part of the oscillation coil 27 is located in the inner region S of the winding part of the power transmission coil 25, and both coils are arranged in a state where they can be electromagnetically coupled. An example of the arrangement in this case is shown in FIGS.
C and D show. Hereinafter, a specific description will be given.

In this example, the power transmission coil 25 is wound by a cement wire and fixed to one component (bobbin-less one).
The printed circuit board 33 is bonded and fixed to a substantially central portion of one surface (front surface) of the printed circuit board 33. on the other hand,
The oscillation coil 27 is configured as one component in which a wire is wound around the coil bobbin 31 and mounted on the other surface (back surface) of the printed circuit board 33 as a surface mount component (SMD). On the other surface (back surface) of the printed circuit board 33,
Other components of the high-frequency oscillation circuit (capacitors C1, C2, resistor R1, transistor Q1, etc.) and components of the power supply circuit are mounted as surface mount components.

In this example, the winding surface of the power transmission coil 25 is parallel to the front and back surfaces of the printed circuit board 33, and the winding surface of the oscillation coil 27 is also parallel to the front and back surfaces of the printed circuit board 33. That is, the power transmission coil 25 and the oscillation coil 27
Is the oscillation coil 27 with respect to the winding surface of the power transmission coil 25.
(When the power transmission coil 25 is placed vertically, the oscillation coil 27 is also placed vertically).

As described above, the components of the charging section are mounted on the printed circuit board 33. By moving the mounting position of the oscillation coil 27, the power transmission coil 25 and the oscillation coil 2 are moved.
7, so that the degree of electromagnetic coupling with No. 7 can be adjusted. In this case, the planar shape of the power transmission coil 25 can be configured as a circle, an ellipse, a square, a polygon, or the like, but the area inside the winding part of the power transmission coil 25 (in the hollow part in the case of a circular air-core coil) is illustrated. Is defined as “inner area S of winding part”.

Then, at least a part of the oscillation coil 27 is located in the inner region S of the winding portion of the power transmission coil 25, and the two coils are arranged so as to be capable of electromagnetically coupling. The magnetic flux φ [Wb] penetrates the oscillation coil 27 so that the direction of the magnetic flux φ is perpendicular to the winding of the oscillation coil 27.

FIG. 4A shows an example in which the oscillation coil 27 is located substantially at the center in the inner region S of the winding portion of the power transmission coil 25. In this example, the magnetic flux φ generated by the power transmission coil 25 passes through the oscillation coil 27. FIG. 4B is an example in which the oscillation coil 27 is located at one corner in the inner region S of the winding portion of the power transmission coil 25. Also in this example, the magnetic flux φ generated by the power transmission coil 25 passes through the oscillation coil 27.

FIG. 4C shows an example in which the oscillation coil 27 is located outside the inner region S of the winding portion of the power transmission coil 25. In this example, since the magnetic flux φ generated by the power transmission coil 25 hardly penetrates the oscillation coil 27, the oscillation operation is possible but the loss is extremely large. FIG. 4D illustrates an example in which the oscillation coil 27 is located outside the inner region S of the winding portion of the power transmission coil 25. In this example, the power transmission coil 25
Is passing through the oscillation coil 27,
The direction of the magnetic flux φ is reverse, and a voltage opposite to the positive feedback during normal operation is applied to the transistor Q1, and the oscillation operation cannot be performed.

As described above, in the states of FIGS. 4A and 4B, a normal oscillating operation is performed and the loss is small. In the state of FIG. 4C, the oscillating operation is possible, but the loss is extremely large. . Then, in the state D in FIG. 4, the direction of the voltage induced in the oscillation coil 27 is reversed, and the oscillation operation stops. Therefore, it is necessary to use it in the state as shown in FIGS.

§4: Arrangement of Coil and Operation of High-Frequency Oscillator Circuit—See FIG. 5 FIG. 5 is a waveform diagram (part 1) of the high-frequency oscillator circuit, where A is Example 1 and B is Example 2. In FIG. 5, I _C is the collector current of the transistor Q1, V _CE is the collector-emitter voltage of the transistor, V _BE is the base-emitter voltage of the transistor Q1, T1 to T5 are each timing (time), and P ₀ is the loss. Is shown.

(1): Explanation of Example 1—See A in FIG. 5 In Example 1 shown in FIG. 5A, the power transmission coil 25 shown in FIG.
FIG. 5 is a waveform diagram in a case where the arrangement of the oscillation coil 27 and the oscillation coil 27 is in the inner region S of the winding portion of the power transmission coil 25 as shown in FIG. In this example, the transistor Q1 is turned off between the timings T1 and T2, the transistor Q1 is turned on between the timings T2 and T3, and the transistor Q1 is turned off between the timings T3 and T5, and the oscillation operation is performed.

That is, a large base-emitter voltage V is applied to the transistor Q1 between the timings T1 and T2.
_BE is applied as a reverse bias and the transistor Q1
Is off (state where the reverse bias is deep), the collector current I _C of the transistor Q1 hardly flows, and the collector-emitter voltage V _CE has a large value.

At timing T2, the transistor Q
1 of the base-emitter voltage V _BE is applied to the transistor Q1 as a positive biased (forward bias), the transistor Q1 is turned on, starts a collector current I _C flows. Then, the collector current I _C gradually increases,
Thereafter, the collector current I _C becomes smaller, the transistor Q1 is turned off at timing T3. Thereafter, similarly, the transistor Q1 performs an oscillating operation while repeating ON / OFF.

In the above operation, the transistor Q1 is turned off at the timing T3.
The timing T4
The collector current I _C continues to flow up to this point. To perform such operations, the loss P ₀ between the timing T3~T4 occurs.

However, in this example, at the timing when the transistor Q1 is to be turned off, the transistor Q1
The base-emitter voltage V _BE becomes a large negative value,
Since a reverse bias is applied to the base of the transistor Q1, the collector current I _C rapidly attenuates, and the transistor Q1 turns off rapidly. Therefore, the loss P ₀ is extremely small and there is no problem. That is, in Example 1, the high-frequency oscillation circuit of the charging unit can perform normal oscillation operation with low loss.

(2): Description of Example 2—See FIG. 5B Example 2 shown in FIG. 5B is a power transmission coil 25 shown in FIG.
FIG. 5 is a waveform diagram in which the arrangement of the oscillation coil 27 and the oscillation coil 27 is not in the inner region S of the winding portion of the power transmission coil 25 as shown in FIG. Also in this example, the transistor Q is connected between the timings T1 and T2 in the same manner as in the example 1.
1 is off, and the transistor Q is turned on between the timings T2 and T3.
1 is ON, and the transistor Q is turned on between the timings T3 and T5.
1 is turned off, and the oscillating operation is performed.

However, in this example, the period during which the transistor Q1 is to be turned off, for example, the timings T1 to T2
During the period or between timings T3 and T5, the base-emitter voltage V _BE applied as a reverse bias to the transistor Q1 is small (the reverse bias is shallow). For this reason, for example, between the timings T3 and T4 when the transistor Q1 should be turned off, the collector current I _C continues to flow for a long time, and the loss P ₀ becomes extremely large.

That is, when the transistor Q1 is turned off from on, the transistor Q1 is turned off by applying a reverse bias to the base of the transistor Q1.
When the reverse bias is small (when the reverse bias is shallow), the transistor Q1 cannot be quickly turned off. Therefore, the timing T3 when the transistor Q1 should be turned off
~ T4, the collector current I _C continues to flow for a long time,
Loss P ₀ becomes extremely large.

§5: Arrangement of coil and bias adjustment of transistor—see FIG. 6 FIG. 6 is a waveform diagram (part 2) of the high-frequency oscillation circuit,
D indicates a base-emitter voltage (V _BE ) waveform of the transistor when the position of the oscillation coil 27 is changed. The waveform of the base-emitter voltage (V _BE ) was set under predetermined experimental conditions, and an experiment was conducted while changing the position of the oscillation coil 27 of the circuit shown in FIG. 3 as shown in FIG.
It is an example of a measured waveform.

(1): FIG. 6A shows a transistor Q1 when the oscillation coil 27 is arranged at the position shown in FIG. 4A.
Is a base-emitter voltage (V _BE ) waveform. In this case, the oscillation coil 27 is located substantially at the center in the inner region S of the winding portion of the power transmission coil 25, and the magnetic flux φ generated by the power transmission coil 25 penetrates the oscillation coil 27. Therefore, a sufficiently large voltage is generated in the oscillation coil 27,
This applies a reverse bias to the base of the transistor Q1.

That is, the base-emitter voltage V _BE of the transistor Q1 is set to V _BE between timings T2 and T3.
= −8 [V], a large reverse bias voltage is applied to the base of the transistor Q1 (a state where the reverse bias is deep), and the oscillation operation is performed normally.

In this experiment, the DC input voltage of the high-frequency oscillation circuit (the DC output voltage of the rectifying / smoothing circuit 28) is set to V _IN ,
The output voltage of the charged part (output voltage of the capacitor C4) is V
_Assuming that _O and the output current (the inflow current of the secondary battery 22) are I _O , V _IN = 14.1 [V], V _O = 5.9 [V], I _O
= 130 [mA].

(2): FIG. 6B shows a transistor Q1 when the oscillation coil 27 is arranged at the position shown in FIG. 4B.
Is a base-emitter voltage (V _BE ) waveform. In this case, the oscillation coil 27 is located at one corner in the inner region S of the winding part of the power transmission coil 25, but the magnetic flux φ generated by the power transmission coil 25 penetrates the oscillation coil 27.

Therefore, a large voltage is generated in the oscillation coil 27 between the timings T2 and T3, and this voltage is applied to the base of the transistor Q1 as a reverse bias.
That is, the base-emitter voltage V _BE of the transistor Q1 is V _BE = -3 [V] between the timings T2 and T3.
This voltage is applied to the base of the transistor Q1 as a reverse bias, and the oscillation operation is performed normally. However, in this example, the reverse bias is smaller than the waveform shown in FIG. 6A.

(3): FIG. 6C shows a transistor Q1 when the oscillation coil 27 is arranged at the position shown in FIG. 4C.
Is a base-emitter voltage (V _BE ) waveform. In this case, the oscillation coil 27 is located outside the inner region S of the winding portion of the power transmission coil 25, and the magnetic flux φ generated by the power transmission coil 25 hardly penetrates the oscillation coil 27.

Therefore, a small voltage is generated in the oscillation coil 27 between the timings T2 and T3, and this voltage is applied to the base of the transistor Q1 as a reverse bias. That is, the base-emitter voltage V _BE of the transistor Q1 becomes V _BE = −between timings T2 and T3.
It is extremely small at about 0.6 [V], and the oscillation operation is possible, but the loss is extremely large.

(4): FIG. 6D shows the transistor Q1 when the oscillation coil 27 is arranged at the position shown in FIG. 4D.
Is a base-emitter voltage (V _BE ) waveform. In this case, the oscillation coil 27 is located outside the inner region S of the winding portion of the power transmission coil 25, and the magnetic flux φ generated by the power transmission coil 25 passes through the oscillation coil 27, but the direction of the magnetic flux φ is The direction is opposite to the case of the positive feedback, and the oscillation is stopped.

As shown in FIGS. 6A to 6D, by changing the position of the oscillation coil 27, the magnitude of the voltage applied as a reverse bias to the base of the transistor Q1 can be changed. Therefore, by adjusting the position of the oscillation coil 27, the bias of the transistor Q1 can be adjusted to an optimum value, and the oscillation operation with the least loss can be performed. The position adjustment of the oscillation coil 27 is performed in a process of incorporating the oscillation coil 27.

§6: Description of power transmission efficiency—see FIGS. 7 and 8 FIG. 7 is an explanatory diagram (part 1) of power transmission efficiency, and FIG. 8 is an explanatory diagram (part 2) of power transmission efficiency. A change in power transmission efficiency when the oscillation coil 27 of the high-frequency oscillation circuit shown in FIG. 3 was moved as shown in FIG. 4 was confirmed by experiments. Hereinafter, the experimental example will be described.

In the above experiment, in the circuit shown in FIG. 3, the DC input power of the charging section (input power of the rectifying / smoothing circuit 28) is P _IN , and the output voltage of the charged section (output voltage of the capacitor C4) is V _{IN O} , the output current (the inflow current of the secondary battery 22) is I _O , the output power is P _O , and the power transmission efficiency is η. Then, η = P _O / P _IN = ｛(V _O × I _O ) /
The power transmission efficiency was determined by the equation P _IN ｝ × 100 [%].

Also, as shown in FIG. 7B, XY orthogonal coordinates are set on the plan view of the power transmission coil 25, and the center position of the power transmission coil 25 is set to the origin 0. Then, the distance from the origin 0 to the position outside the oscillation coil 27 is x (+ x,
-X), an experiment was performed while changing x. The power transmission efficiency η obtained as a result changed as shown in FIG.

In FIG. 7A, when x is in the area S, the position of the oscillation coil 27 is in the area inside the winding portion of the power transmission coil 25, that is, when the oscillation coil 27 is This is the case where it is located at the positions indicated by A and B in FIG. As described above, if the position of the oscillation coil 27 is within the inner region S of the winding portion of the power transmission coil 25, the position of the oscillation coil 27 is the optimum position, and power transmission can be performed with the highest efficiency. I understand.

In FIG. 7A, when x is within the range of M, the oscillation coil 27 is in the position shown in FIG. 4C. In this state, self-sustained pulsation is possible, but the loss becomes extremely large, and the power transmission efficiency also deteriorates.
Further, in FIG. 7A, when x is within the region of N,
This is a state in which the oscillation coil 27 is at the position shown in FIG. In this state, self-sustained pulsation cannot be performed, and power transmission cannot be performed. The oscillation operation can be performed even when the oscillation coil 27 is extremely far away from the power transmission coil 25 and is not electromagnetically coupled to each other. However, the loss is extremely large, the power transmission efficiency is extremely deteriorated, and it is not practical.

For comparison of the power transmission efficiency η,
An experiment was conducted with the position of the oscillation coil 27 shown in FIGS. 4A and 4B and the position shown in FIG. 4C, and the data shown in FIG. 8 was obtained. In FIG. 8, the horizontal axis represents the output current I _O
[MA], the vertical axis indicates the efficiency η [%], and the oscillation coil 27
4 shows the efficiency at the positions shown in FIGS. 4A and 4B, and shows the position of the oscillation coil 27 at the position shown at C in FIG.

The efficiency η shown in the above shows high efficiency over a wide range with respect to the change in the output current I _O , but the efficiency η shown in the above shows a lower efficiency as a whole with respect to the change in the output current I _O It has been found. As an example, when the value of the output current I _O is I _O = 130 [mA], the efficiency η is η = 6.
The efficiency η was 0% and η was 41%. Therefore, the difference between the efficiency and is 60−41 = 19%,
It can be seen that the efficiency is ideal.

§7: Description of coil mounting example—see FIGS. 9 and 10 FIG. 9 shows a coil mounting example of the charging section, where A is a power transmission coil unit example 1 (plan view and side view), and B is Power transmission coil unit example 2 (plan view and side view), C is an example (perspective view) of a power transmission coil unit and a power reception coil. FIG. 10 is an explanatory view of the coil arrangement in the charged state. A is when the power transmission coil unit shown in FIG. 9A is used, B is when the power transmission coil unit shown in FIG. 9B is used, and C is the power transmission coil 25. It is explanatory drawing in the case of using an air-core coil as a receiving coil. Hereinafter, a coil mounting example will be described with reference to FIGS. 9 and 10.

(1): In the power transmission coil unit example 1 shown in FIG. 9A, the power transmission coil 25 is formed as a fixed one-piece (air-core coil) by being wound with a cement wire. Is adhered and fixed to the approximate center of the surface (surface). On the other hand, the oscillating coil 27 is configured as one component in which a wire is wound around the coil bobbin 31,
It is mounted on the other surface (back surface) of the printed circuit board 33 as a surface mount component (SMD).

Further, on the other surface (back surface) of the printed board 33, other components of the high-frequency oscillation circuit and components of the power supply circuit are mounted as surface mount components. In this case, the oscillation coil 27 is located at one corner in the inner region S of the winding portion of the power transmission coil 25, and the magnetic flux φ generated by the power transmission coil 25 passes through the oscillation coil 27.

(2): In the power transmission coil unit example 2 shown in FIG. 9B, the power transmission coil 25 is formed as a fixed component (air-core coil) wound around a cement wire, and Is adhered and fixed to the approximate center of the surface (surface). On the other hand, the oscillating coil 27 is also formed as one part (air-core coil) wound and fixed by the cement wire, on one surface (front surface) of the printed circuit board 33, and in the hollow portion of the power transmission coil 25. Adhesively fixed.

Further, on the other surface (back surface) of the printed circuit board 33, other components of the high-frequency oscillation circuit and components of the power supply circuit are mounted as surface mount components. Again,
This is an example in which the oscillation coil 27 is located at one corner in the inner region S of the winding portion of the power transmission coil 25.
Generated through the oscillation coil 27.

(3): In the example of the power transmitting coil unit and the power receiving coil shown in FIG. 9C, the power transmitting coil unit shown in FIG. 9A or B is used. The power receiving coil 26 used in combination with the power transmitting coil unit is:
For example, it is configured as one component (air-core coil) that is wound and fixed by a cement wire.

(4): In the arrangement example 1 shown in FIG.
The power transmitting coil unit shown in FIG. 9A and the power transmitting coil unit shown in FIG.
9 shows an example of coil arrangement in a charged state by a combination of the power receiving coils 26 shown in FIG. In this state, the oscillation coil 27 is located at one corner in the inner area S of the winding part of the power transmission coil 25, and the magnetic flux φ generated by the power transmission coil 25
Penetrates the oscillation coil 27.

(5): In the arrangement example 2 shown in FIG.
The power transmitting coil unit shown in FIG. 9B and the power transmitting coil unit shown in FIG.
9 shows an example of coil arrangement in a charged state by a combination of the power receiving coils 26 shown in FIG. In this state, the oscillation coil 27 and the power transmission coil 25 are arranged on the same surface of the printed circuit board 33, and the oscillation coil 27 is arranged at one corner in the hollow portion of the power transmission coil 25. The magnetic flux φ generated by the power transmission coil 25 passes through the oscillation coil 27.

(6): FIG. 10C shows the power transmitting coil unit shown in FIG. 9A and the power receiving coil 26 shown in FIG. 9C.
This is an example in which a combination is used. In this case, the power transmission coil unit is mounted in the charger case 24 shown in FIG. 2, and the power receiving coil 26 is mounted in the cordless phone slave device case 23.

Then, when the cordless phone handset case 23 is placed on the charger case 24 and put in a charged state, FIG.
0, the transmitting coil 25 and the receiving coil 2
6 are positioned at the opposing positions, so that non-contact power transmission from the power transmission coil 25 to the power reception coil 26 can be performed.

In this case, the power transmitting coil 25 and the power receiving coil 2
6 uses a coil wound by a cement wire without using a coil bobbin, so that a cordless phone handset case 23 is provided between the power transmitting coil 25 and the power receiving coil 26.
, And the thickness of the charger case 24, and the distance between both coils is minimized. Therefore, power transmission can be performed efficiently.

§8: Description of Coil Arrangement in Another Embodiment—See FIG. 11 FIG. 11 is a diagram illustrating an example of coil arrangement in another embodiment, where A is Example 1 and B is Example 2. , C is Example 3; D is Example 4; and E is a partially enlarged view of Example 3. Hereinafter, an arrangement relationship between the power transmission coil 25 and the oscillation coil 27 in another embodiment will be described with reference to FIG.

As described in the above-mentioned conventional example, in order to be able to use the Hartley oscillation circuit as the high-frequency oscillation circuit of the charging section, the power transmission coil 25 and the oscillation coil 27 must be used.
It is necessary to be able to adjust the degree of electromagnetic coupling with the magnetic field. Therefore, in this example, the power transmission coil 25 and the oscillation coil 27 are configured as separate and independent coil components, and are arranged such that the winding surface of the oscillation coil 27 is perpendicular to the winding surface of the power transmission coil 25. In addition, at least a part of the oscillation coil 27 is located in a winding area of the power transmission coil 25, and the two coils are arranged so as to be electromagnetically coupleable.

That is, the winding surface of the power transmission coil 25 is arranged parallel to the front and back surfaces of the printed circuit board 33, and the oscillation coil 2
The winding surface of No. 7 is arranged perpendicularly to the front and back surfaces of the printed circuit board 33 (when the power transmission coil 25 is placed vertically, the oscillation coil 27 is placed horizontally). In this example, the winding width W of the power transmission coil 25 and the coil length L of the oscillation coil 27 are equal (W = L), but the embodiment can be implemented with any size.

The arrangement examples in this case are shown in FIGS.
D. Hereinafter, XY orthogonal coordinates are set as shown in the figure, and a specific description will be given. In this example, the power transmission coil 25
Is wound as a fixed part (one bobbin-less coil part) by a cement wire, and is adhered and fixed to a substantially central portion of one surface (front surface) of the printed circuit board 33. In this case, the printed circuit board 33 and the power transmission coil 2
The winding surface of No. 5 is parallel to the X axis.

On the other hand, the oscillating coil 27 is composed of a cylindrical ferrite core 35 serving as a center pole and a coil wound therearound as one component, and the other surface (back surface) of the printed circuit board 33 is provided with a surface mount component ( SMD). The other surface (back surface) of the printed circuit board 33
Includes other components of the high-frequency oscillation circuit (capacitors C1, C
2, a resistor R1, a transistor Q1, etc.) and components of a power supply circuit are mounted as surface mount components (not shown).

In this manner, the components of the charging section are mounted on the printed circuit board 33. By moving the mounting position of the oscillation coil 27, the power transmission coil 25 and the oscillation coil 2 are moved.
7, so that the degree of electromagnetic coupling with No. 7 can be adjusted. In this case, the planar shape of the power transmission coil 25 can be configured as a circle, an ellipse, a square, a polygon, or the like.
An area below the winding part of the power transmission coil 25 (X in the winding part)
(Axial width) is defined as “winding region M”.

Example 1 shown in FIG.
This is an example in which an oscillation coil 27 is arranged at the center of the inner region S of the winding portion of No. 5. In this case, it is generated in the power transmission coil 25,
The direction of the magnetic flux φ passing near the oscillation coil 27 is in the Y-axis direction, and the winding surface of the oscillation coil 27 is placed parallel to the Y-axis. 27 does not penetrate. Therefore, the power transmission coil 25 and the oscillation coil 27 are not electromagnetically coupled, and neither positive feedback nor negative feedback is applied to the transistor Q1 of the Hartley oscillation circuit. In this case, oscillation operation is possible, but loss is large and power transmission efficiency is reduced.

Example 2 shown in FIG. 11B is an example in which the oscillation coil 27 is located at one corner of the inner region S of the winding portion of the power transmission coil 25. In this example, the magnetic flux φ generated by the power transmission coil 25 slightly penetrates the oscillation coil 27. In this case, oscillation operation is possible, but loss is large and power transmission efficiency is reduced.

Example 3 shown in FIG. 11C is an example in which the oscillation coil 27 is located in the winding area M of the power transmission coil 25, and a partially enlarged view is shown in FIG. 11E. At this position, the magnetic flux φ generated by the power transmission coil 25 penetrates the oscillation coil 27 best, and the degree of magnetic coupling between both coils is the highest. Therefore, positive feedback is best applied to the transistor Q1, and an ideal oscillation operation with the least loss can be performed.

Example 4 shown in FIG. 11D is an example in which the oscillation coil 27 protrudes outside the winding area M of the power transmission coil 25. However, at least a part of the oscillation coil 27 is in the winding area M. In this position, the magnetic flux φ generated by the power transmission coil 25 is
7 is a position where the magnetic flux φ penetrating gradually decreases as the oscillation coil 27 moves away from the winding area M. However, in this position, the oscillating operation is performed normally with low loss, so that the operation can be performed in the same manner as the position C in FIG.

When the position of the oscillation coil 27 is outside the winding area M of the power transmission coil 25, the transistor Q
1 does not receive an appropriate reverse bias, resulting in a lossy oscillation operation. Further, even when the oscillation coil 27 is far away from the winding region M (for example, when it is more than twice the diameter of the power transmission coil 25 in the X-axis direction), the oscillation operation is possible, And the power transmission efficiency also decreases.

As described above, in the states C and D in FIG. 11, the normal oscillating operation is performed and the loss is small.
In the state B, the oscillation operation is possible, but the loss is extremely large. Therefore, it is desirable to use it in the state as shown in FIGS.

In the other embodiment, the position of the oscillating coil 27 is changed so that the transistor Q
The magnitude of the voltage applied as a reverse bias to one base can be changed. Therefore, by adjusting the position of the oscillation coil 27, the bias of the transistor Q1 can be adjusted to an optimum value, and the oscillation operation with the least loss can be performed. The position adjustment of the oscillation coil 27 is performed in a process of incorporating the oscillation coil 27.

§9: Description of power transmission efficiency in another embodiment—see FIG. 12 FIG. 12 is an explanatory diagram of power transmission efficiency in another embodiment. The oscillation coil 2 of the high-frequency oscillation circuit shown in FIG.
The change of the power transmission efficiency when No. 7 was moved as shown in FIG. 11 was confirmed by an experiment. Hereinafter, the experimental example will be described.

In the above experiment, in the circuit shown in FIG.
DC input power of the charging section (input power of the rectifier / smoothing circuit 28) is P _IN , output voltage of the charged section (output voltage of the capacitor C4) is V _O , and output current (inflow current of the secondary battery 22).
Is I _O , the output power is P _O , and the power transmission efficiency is η. Then, η = P _O / P _IN = {(V _O × I _O ) / P _IN } × 1
The power transmission efficiency was determined by the equation of 00 [%].

Further, as shown in FIG. 12, XY orthogonal coordinates are set, and the center position of the power transmission coil 25 is set to the origin 0. The experiment was performed while changing the distance x (+ x, -x) in the X-axis direction from the origin 0 to the outside of the oscillation coil 27. The power transmission efficiency η obtained as a result changed as shown in FIG.

In FIG. 12, when x is in the area of S, the position of the oscillation coil 27 is in the area inside the winding portion of the power transmission coil 25, that is, the oscillation coil 2
7 is in the position shown in FIGS. 11A and 11B. As described above, when the position of the oscillation coil 27 is within the inner region S of the winding portion of the power transmission coil 25, the power transmission efficiency η becomes η
= 46%.

In FIG. 12, when x is within the range of M, for example, the oscillation coil 27 is in the position shown in FIG. 11C (just below the power transmission coil 25).
In this state, the magnetic flux φ generated by the power transmission coil 25 penetrates the oscillation coil 27 best, and the degree of magnetic coupling between both coils is highest.

Therefore, the positive feedback is best applied to the transistor Q1, the loss is the smallest, and the power transmission efficiency η is the highest. That is, at this position, the efficiency η is the maximum η
= 60%, which is the most desirable position. Note that at least a part of the oscillation coil 27 is
5 (for example, state D in FIG. 11), it was confirmed that the power transmission efficiency was high and the oscillation operation with little loss was performed as described above.

Further, in FIG. 12, when it is within the range of x = N, the oscillation coil 27 is farther away from the position shown in FIG. 11D. In this state, the magnetic flux φ generated by the power transmission coil 25 penetrates the oscillation coil 27, but the magnetic flux penetrating decreases. Therefore, in this region, the power transmission efficiency η also decreased to about η = 46%.

(Other Embodiments) Although the embodiments have been described above, the present invention can be implemented as follows.

(1): power transmission coil 25, oscillation coil 2
7. The power receiving coil 26 may be an air-core coil, but a core (for example, a ferrite core) may be inserted into the coil. (2): The power transmission coil 25, the oscillation coil 27, and the power reception coil 26 can be implemented in any shape such as a circle, an ellipse, a square, and a polygon.

[0108]

As described above, the present invention has the following effects. (1): By changing the position of the oscillation coil with respect to the power transmission coil, it is possible to always adjust the reverse bias of the transistor constituting the Hartley oscillation circuit to an optimum value. Therefore, the Hartley oscillation circuit can be used as the high-frequency oscillation circuit of the charging unit constituting the non-contact power transmission device, so that the number of components can be reduced and the cost can be reduced.

(2): Since the reverse bias of the transistor constituting the Hartley oscillation circuit can always be adjusted to an optimum value, the loss can be reduced and the power transmission efficiency can be improved.

(3): By changing the position of the oscillation coil with respect to the power transmission coil, the reverse bias of the transistor constituting the Hartley oscillation circuit can always be adjusted to an optimum value. Therefore, even if the oscillation coil is miniaturized, an oscillation operation with little loss can be performed. That is, even if the oscillation coil is extremely small compared to the power transmission coil, the Hartley oscillation circuit can be driven with low loss and the power transmission efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a configuration diagram of a cordless phone according to the embodiment.

FIG. 3 is a circuit diagram in the embodiment.

FIG. 4 is a diagram illustrating an example of the arrangement of coils according to the embodiment.

FIG. 5 is a waveform diagram (part 1) of the high-frequency oscillation circuit in the embodiment.

FIG. 6 is a waveform diagram (part 2) of the high-frequency oscillation circuit according to the embodiment.

FIG. 7 is an explanatory diagram (part 1) of power transmission efficiency in the embodiment.

FIG. 8 is an explanatory diagram (part 2) of power transmission efficiency in the embodiment.

FIG. 9 is a coil mounting example in the embodiment.

FIG. 10 is an explanatory diagram of a coil arrangement in a charged state in the embodiment.

FIG. 11 is an explanatory diagram of a coil arrangement example according to another embodiment.

FIG. 12 is an explanatory diagram of power transmission efficiency in another embodiment.

FIG. 13 is an explanatory diagram (part 1) of a conventional example.

FIG. 14 is an explanatory view (part 2) of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Charger 21 Cordless phone handset 22 Secondary battery 23 Cordless phone handset case 24 Charger case 25 Power transmission coil 26 Power reception coil 27 Oscillation coil 28 Rectification / smoothing circuit 33 Printed circuit board 35 Ferrite core

Claims (2)

[Claims] The charging section and the charging section are detachably separated from each other. The charging section includes a power transmission coil and a high-frequency oscillation circuit for driving the power transmission coil. A non-contact power transmission device that includes a power receiving coil for electromagnetically coupling with the power transmission coil to induce a voltage, and that transmits power from the charging unit to the charged unit in a non-contact manner. A Hartley oscillation circuit including a coil and the power transmission coil, the power transmission coil and the oscillation coil are arranged such that the winding surface of the oscillation coil is parallel to the winding surface of the power transmission coil, And at least a part of the oscillation coil is located in an inner region of a winding part of the power transmission coil, and the two coils are arranged in a state where they can be electromagnetically coupled. Transmission equipment. 2. A charging section and a charging section are detachably separated from each other. The charging section includes a power transmission coil and a high-frequency oscillation circuit for driving the power transmission coil. A non-contact power transmission device that includes a power receiving coil for electromagnetically coupling with the power transmission coil to induce a voltage, and that transmits power from the charging unit to the charged unit in a non-contact manner. It comprises a Hartley oscillation circuit including a coil and the power transmission coil, the power transmission coil and the oscillation coil are arranged such that the winding surface of the oscillation coil is perpendicular to the winding surface of the power transmission coil, And,
A non-contact power transmission device, wherein at least a part of the oscillation coil is located in a winding area of the power transmission coil, and the two coils are arranged in a state where they can be electromagnetically coupled.