JP2008167582A - Non-contact power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact power transmission device capable of preventing a metallic piece such as a coin from generating heat without affecting charging of a portable apparatus. <P>SOLUTION: In this non-contact power transmission device which includes a charging device body 10 in which a power transmission coil L1 for charging is built in, and a support base formed at a part of the body for detachably mounting the portable apparatus 20 in which a power receiving coil L2 for charging is built in to transmit power without contact by using electromagnetic induction from the power transmitting coil L1 to the power receiving coil L2, permanent magnets M1, M2 are provided with the portable apparatus, magnet detecting devices IC1, IC2 are provided at a position of the support base so as to face the permanent magnet, and the permanent magnet and the magnet detecting device are made to be a pair, forming a plurality of pairs thereof. Only when the plurality of magnet detecting devices detect the magnetic field of the permanent magnet, the portable apparatus detects that the support base is correctly placed at the predetermined position, and power is transmitted from the power transmitting coil to the power receiving coil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a non-contact power transmission device for charging a secondary battery built in an electronic device such as a portable device without contact.

  In a non-contact power transmission system, in a support base formed in a part of a main body for detachably mounting a charging device main body incorporating a power transmission coil for charging and a portable device incorporating a power receiving coil for charging, If the charging device does not start power transmission after recognizing that the portable device is mounted at a predetermined position of the support base, it is not preferable for safety. For example, as shown in FIG. 6A, when a metal piece such as a coin is in the vicinity of the power transmission coil L1, if the electric power is always transmitted, the metal piece generates heat due to the principle of electromagnetic induction, which is dangerous.

  In order to avoid such heat generation by the metal piece, Patent Document 1 discloses that the metal piece is supported by devising the shape of the support base 11 in the stationary charging device 10 of the portable device 20 as shown in FIG. Even if the metal piece x is placed on the table, it is avoided by mounting the portable device 20 so that the power transmitting and receiving coils L1 and L2 are arranged obliquely. However, there is a problem that the charging efficiency is deteriorated due to the displacement of the power transmission coil L1 and the power receiving coil L2 due to the placement of the metal piece x, and the charging time becomes long. There was a problem that made it difficult to design.

  Further, Patent Document 2 includes a power transmission coil and a detection coil in a power transmission side circuit, detects a change in charging load by an electromotive force generated in the detection coil, and only when it is detected that the charging load has changed in a predetermined pattern. The output of the power transmission coil is changed to a strong magnetic field. The power receiving side circuit includes a power receiving coil and a control element for charging the secondary battery, and has a function of turning the control element on and off at the start of charging to vary the charging load in a predetermined pattern. The charging load in a state where a foreign object is placed is recognized, and the output of the charging coil is controlled. However, it is not economical to shorten the battery life because a complicated circuit is provided in a power receiving side circuit used for a portable device or the like and unnecessary energy is consumed.

JP 2000-37047 A JP 2002-34169 A

  Thus, in Cited Document 1, the portable device is only mounted obliquely, and if the metal piece adheres to the vicinity of the power transmission coil, the metal piece is still heated and dangerous. Further, the cited document 2 has a problem that wasteful energy is consumed in order to provide a complicated circuit on the portable device side.

  The present invention has been made to solve the above-described problems, and does not provide a complicated circuit on the portable device side, does not hinder charging of the portable device, and heats a metal piece such as a coin. There is no. Moreover, it aims at providing the non-contact electric power transmission apparatus which suppressed the standby | standby electric power when the portable apparatus is not mounted.

A non-contact power transmission device according to the present invention is formed in a part of the main body for detachably mounting a charging device main body incorporating a charging power transmission coil and a portable device incorporating a charging power receiving coil. A non-contact power transmission device that transmits power from the power transmission coil to the power reception coil in a non-contact manner using electromagnetic induction, wherein a permanent magnet is provided in the portable device, and the permanent magnet is mounted on the support base. A magnetic field detection element is provided at an opposing position, the permanent magnet and the magnetic field detection element are set as one set, and a plurality of sets are provided, and only when the plurality of magnetic field detection elements detect the magnetic field of the permanent magnet, It is detected that the device is correctly placed at a predetermined position, and power is transmitted from the power transmission coil to the power reception coil.
Further, the plurality of permanent magnets are arranged at intervals on the bottom surface of the portable device and other surfaces other than the bottom surface, and a plurality of magnetic field detection elements are arranged on the support base at positions facing the permanent magnets of the portable device. . Further, the magnetic field detection element is composed of a Hall IC incorporating a Hall element.

  In the non-contact power transmission device according to the present invention, when a metal piece such as a coin adheres to the support base of the charging device body, that is, when the portable device cannot be placed in a normal state, a plurality of sets of magnetic field detection elements Since the magnetic field of some or a plurality of permanent magnets cannot be detected due to the relationship between the magnetic field detecting element and the permanent magnet, the switch circuit connected to the magnetic field detecting element does not operate and power is not transmitted from the power transmitting coil to the power receiving coil. Therefore there is no danger of heat generation. Further, when no portable device is placed, it is economical because it is weak standby power necessary for driving only the first magnetic field detection element. Further, on the mobile device side, by using a plurality of minute and light permanent magnets, unnecessary power is not required, and the built-in secondary battery can be used effectively.

  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in FIGS.

1 and 2 are block diagrams showing an embodiment of a non-contact power transmission apparatus according to the present invention.
The contactless power transmission device shown in FIG. 1 and FIG. 2 is a support for detachably mounting a charging device body 10 incorporating a charging power transmission coil L1 and a portable device 20 incorporating a charging power receiving coil L2. A table 11 (see FIG. 6) is formed.
Here, the power receiving coil L2 of the portable device is provided on the back as shown in FIG. 6B, but may be provided on the bottom as shown in FIG. 6A. Similarly, the power transmission coil L1 is disposed on a support base that faces the power reception coil L2 of the mobile device 20.

  The contactless power transmission device shown in FIG. 1 includes a charging device main body 10, a power transmission circuit 1 including a charging power transmission coil L <b> 1, a first switch circuit S <b> 1 that turns on and off an input power source Vin for the power transmission circuit 1, and a second switch circuit S <b> 1. The switch circuit S2 is connected in series. The first switch circuit S1 is ON / OFF controlled by an output signal from the output terminal Out of the first Hall IC IC1 incorporating a Hall element as a magnetic field detection element. The second switch circuit S2 is ON / OFF controlled by an output signal from the output terminal Out of the second Hall IC IC2 incorporating a Hall element as a magnetic field detection element. The first Hall IC IC1 and the second Hall IC IC2 are arranged on the surface of the support 11 that supports the bottom surface of the portable device 20 (a and b in FIG. 6B) or on the back surface (c in FIG. 6B). It is incorporated. The power transmission circuit 1 includes resonance capacitors C1 and C2 in parallel with the transmission and reception coils L1 and L2.

The portable device 20 includes a power receiving coil L2 that receives power from the power transmitting coil L1 by electromagnetic induction, a charging circuit 2 that charges the secondary battery B, and another circuit (not shown) that is a main purpose. ing. Furthermore, the portable device 20 includes a bottom surface (see FIG. 6B) of the casing of the portable device 20 that faces the first and second Hall ICs IC1 and IC2 incorporated in the support base 11 that is the charging device body 10. Permanent magnets M1 and M2 are incorporated in a, b) or the back surface (c in FIG. 6B).
When the two Hall ICs IC1 and IC2 incorporated in the support base 11 of the charger body 10 and the two permanent magnets M1 and M2 incorporated in the portable device are close to each other, that is, the portable device 20 is attached to the support base 11. When correctly placed in a predetermined state, the two Hall ICs detect the magnetic field of the permanent magnet, turn on the first and second switch circuits S1 and S2, operate the power transmission circuit 1, and operate from the power transmission coil. Electric power is supplied to the power receiving coil, and the built-in secondary battery is charged through the smoothing circuit.

  The non-contact power transmission device shown in FIG. 2 includes a power transmission circuit 1 including a charging coil L1 for charging, a first switch circuit S1 for turning on / off an input power source Vin in the power transmission circuit 1, and power transmission. A second switch circuit S2 for turning on / off the switching element Q1 of the circuit 1 is provided. The first switch circuit S1 is ON / OFF controlled by an output signal from the output terminal Out of the first Hall IC IC1 incorporating a Hall element as a magnetic field detection element. The second switch circuit S2 is ON / OFF controlled by an output signal from the output terminal Out of the second Hall IC IC2 incorporating a Hall element as a magnetic field detection element. The first Hall IC IC1 and the second Hall IC IC2 are arranged on the surface of the support 11 that supports the bottom surface of the portable device 20 (a and b in FIG. 6B) or on the back surface (c in FIG. 6B). It is incorporated. The power transmission circuit 1 includes resonance capacitors C1 and C2 in parallel with the transmission and reception coils L1 and L2.

The portable device 20 includes a power receiving coil L2 that receives power from the power transmitting coil L1 by electromagnetic induction, a charging circuit 2 that charges the secondary battery B, and another circuit (not shown) that is a main purpose. ing. Furthermore, the portable device 20 includes a bottom surface (see FIG. 6B) of the casing of the portable device 20 that faces the first and second Hall ICs IC1 and IC2 incorporated in the support base 11 that is the charging device body 10. Permanent magnets M1 and M2 are incorporated in a, b) or the back surface (c in FIG. 6B).
When the two Hall ICs IC1 and IC2 incorporated in the support base 11 of the charger body 10 and the two permanent magnets M1 and M2 incorporated in the portable device are close to each other, that is, the portable device 20 is attached to the support base 11. When correctly placed in a predetermined state, the two Hall ICs detect the magnetic field of the permanent magnet, turn on the first and second switch circuits S1 and S2, operate the power transmission circuit 1, and operate from the power transmission coil. Electric power is supplied to the power receiving coil, and the built-in secondary battery is charged through the smoothing circuit.

Here, for example, when a metal piece such as a coin adheres to the support base, the attachment causes a gap between the support base and the mobile device, that is, the mobile device is in a floating state, and the one or two holes are provided. The IC cannot detect the magnetic field of the permanent magnet, and power is not transmitted from the charger body to the portable device.
Thus, in the non-contact power transmission device according to the present invention, even if one Hall IC detects the magnetic field of the permanent magnet by combining a plurality of Hall ICs and permanent magnets to turn on and off the plurality of switch circuits. Unless the Hall ICs at other locations detect the magnetic field of the permanent magnet, the plurality of switch circuits are not turned on, and the power transmission circuit does not start operation. Therefore, heat is not generated by the metal piece without supplying unnecessary power. Increasing the number of combinations of Hall ICs and permanent magnets reduces the risk of malfunction, but the practicality due to the mounting of the support base and the portable device decreases. Depending on the configuration and application, the number of sets may be further increased.

FIG. 3 shows a circuit diagram of an example of the charging device main body 10 of the block diagram shown in FIG. 1 in one embodiment of the non-contact power transmission apparatus according to the present invention.
3 includes a power transmission circuit 1 using a self-excited oscillation circuit, and a first switch circuit S1 and a second switch circuit S2 that turn on and off the input power source of the power transmission circuit 1. The first switch circuit S1 is turned on / off by an output signal from the output terminal Out of the Hall IC IC1, and the second switch circuit S2 is turned on / off by an output signal from the output terminal Out of the Hall IC IC2.

  Here, the resistors R10 and R11 are divided resistors that generate the drive voltage Vcc of the Hall IC IC1, and R6 and R7 are divided resistors that generate the drive voltage Vcc of the Hall IC IC2. The first switch circuit S1 includes a MOSFET Q4 as a switching element, and the resistors R8 and R9 are bias resistors. The second switch circuit S2 includes a MOSFET Q5 as a switching element, and resistors R12 and R13 are Q5 bias resistors.

FIG. 4 shows a circuit diagram of an example of the charging device main body 10 of the block diagram shown in FIG. 2 in another embodiment of the non-contact power transmission apparatus according to the present invention.
4 shows a power transmission circuit 1 using a self-excited oscillation circuit, a first switch circuit S1 for turning on / off an input power source of the power transmission circuit 1, and a second switch circuit for turning on / off a switching element Q1 of the power transmission circuit 1. S2 is provided. The first switch circuit S1 is turned on / off by an output signal from the output terminal Out of the first Hall IC IC1, and the second switch circuit S2 is turned on / off by an output signal from the output terminal Out of the second Hall IC IC2. .

  Here, the resistors R10 and R11 are divided resistors that generate the drive voltage Vcc of the Hall IC IC1, and R6 and R7 are divided resistors that generate the drive voltage Vcc of the Hall IC IC2. The first switch circuit S1 includes a MOSFET Q4 as a switching element, and resistors R8 and R9 are bias resistors of the MOSFET Q4. The second switch circuit S2 includes a switching transistor Q2, and resistors R4 and R5 are bias resistors for the switching transistor Q2.

  As described above, the non-contact power transmission apparatus according to the present invention includes only the first Hall IC that controls the first switching circuit in a state where the portable device is not placed on the support base, that is, in the standby state. Since power transmission (charging) is not started unless the power supply Vcc is small and the portable device is not normally set on the support base of the charging device, there is a risk of unnecessary power loss and heat generation during standby. Absent. Even if metal or the like is placed on the support base, the positional relationship between the two sets of Hall elements and the permanent magnets is different, and the operation of the power transmission circuit is in a stopped state, so that unnecessary power loss and heat generation do not occur.

In addition, the Hall IC used above is 3 mm square in length and width, about 1 mm in heat, and is light, thin, small and flexible. Also, the permanent magnet can be a sphere having a diameter of 3 mm or less, an elliptical sphere having a reduced thickness, or a square, and can be easily incorporated and is extremely lightweight.
In addition, it is more preferable that the positional relationship between the two Hall ICs and the two permanent magnets be as far apart as possible so as not to erroneously detect each other's magnetic field. Furthermore, it is preferable that the error detection accuracy can be further improved by arranging two-dimensionally such as a bottom surface and a side surface (back surface) instead of only a plane.

  As shown in FIG. 5A, the Hall IC includes a Hall element 30, an amplifier 31, a Schmitt trigger circuit 32, a power supply Vcc, an output-side transistor 33, an output resistor 34, an output terminal Vout, and a ground GND. It is configured. A current is passed through the Hall element 30, and the Hall IC and the permanent magnet are arranged so that the magnetic field of the permanent magnet is applied in a direction perpendicular to the current of the Hall element 30. The Hall element 30 has a phenomenon in which a potential difference is caused in the direction perpendicular to the current and the applied magnetic field, that is, a Hall effect. This potential difference is amplified by the amplifier 31, and further, the Schmitt circuit 32 gives hysteresis characteristics to the potential difference to drive the transistor 33 at the output end to output a signal from the output terminal Vout of the Hall IC. It is comprised so that it may drive.

  FIG. 5B is a diagram showing the magnetoelectric conversion characteristics of the Hall IC. When the current flowing through the Hall element 30 is constant, the applied magnetic field is proportional to the potential difference caused by the Hall effect. Therefore, if the Hall IC has a hysteresis characteristic in the potential difference by the Schmitt circuit 32 as shown in the figure, the Hall IC functions as a magnetic switch in accordance with the attachment / detachment of the portable device 20, and the Hall ICs and permanent magnets provided at two locations are predetermined. In the position, that is, when the portable device 20 is placed at the normal position of the support base 11 of the charging device, the power transmission circuit is activated only after the first switch circuit and the second switch circuit are turned on, Electric power is transmitted from the charging device body 10 to the portable device 20 in a contactless manner.

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, in the above embodiment, the self-excited oscillation circuit is used as the power transmission circuit of the charging device body, but another example oscillation circuit may be used.

The block diagram which shows one Embodiment of the non-contact electric power transmission apparatus which concerns on this invention The block diagram which shows other embodiment of the non-contact electric power transmission apparatus which concerns on this invention The circuit diagram which shows one Example of the non-contact electric power transmission apparatus which concerns on this invention The circuit diagram which shows the other Example of the non-contact electric power transmission apparatus which concerns on this invention Configuration diagram showing Hall IC (a) and graph showing magnetoelectric conversion characteristics (b) Schematic diagram of the relationship between the main body of the charging stand and the portable device in the non-contact power transmission device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Charging apparatus main body 20 Portable apparatus 1 Electric power transmission circuit 2 Charging circuit L1 Power transmission coil L2 Power reception coils C1, C2 Resonance capacitor B Secondary battery S1 First switch circuit S2 Second switch circuit IC1 First hall IC
IC2 Second Hall IC

Claims (4)

A charging device main body with a built-in charging power transmission coil, and a support base formed on a part of the main body for detachably mounting a portable device with a built-in charging power receiving coil; In the non-contact power transmission device that transmits power in a non-contact manner using electromagnetic induction in the power receiving coil,
The portable device is provided with a permanent magnet, the support base is provided with a magnetic field detection element at a position facing the permanent magnet, the first permanent magnet and the first magnetic field detection element are set as one set, and a plurality of sets are provided. Only when detecting the magnetic field of the permanent magnet, that is, detecting that the portable device is correctly placed at a predetermined position of the support base, and transmitting power from the power transmission coil to the power reception coil. Non-contact power transmission device. A charging device main body with a built-in charging power transmission coil, and a support base formed on a part of the main body for detachably mounting a portable device with a built-in charging power receiving coil; In the non-contact power transmission device that transmits power in a non-contact manner using electromagnetic induction in the power receiving coil,
The portable device is provided with first and second permanent magnets, the support base is provided with a first magnetic field detecting element at a position facing the first permanent magnet, and a second at a position facing the second permanent magnet. Only when the first and second magnetic field detection elements detect the magnetic fields of the opposing permanent magnets, that is, when the portable device is correctly placed at a predetermined position on the support base. And a non-contact power transmission device that transmits power from the power transmission coil to the power reception coil. The plurality of permanent magnets are arranged at intervals on the bottom surface of the portable device and other surfaces other than the bottom surface, and a plurality of magnetic field detecting elements are arranged on the support base at positions facing the permanent magnets of the portable device. The contactless power transmission device according to claim 1, wherein The non-contact power transmission device according to claim 1, wherein the magnetic field detection element is a Hall IC including a Hall element.

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