JP4256426B2 - Non-contact power transmission device - Google Patents

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. 5, when a metal piece x such as a coin is in the vicinity of the power transmission coil L1, if the 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 due to the metal piece x, Patent Document 1 devised the shape of the support base 11 in the stationary charging device 10 of the portable device 20 to mount the portable device 20 obliquely. And the power transmission coil L1 is arrange | positioned in the inclination part of the support stand 11, and the receiving coil L2 is installed in the back surface of the portable apparatus 20, and is provided so that the power transmission coil L1 may be opposed. In this way, the mobile device 20 is avoided by being mounted 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 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-mentioned problems, authenticates that the portable device is correctly placed on the support base, avoids power transmission at the time of abnormality, and generates heat by a metal piece such as a coin. An object of the present invention is to provide a non-contact power transmission device for preventing the above.

A non-contact power transmission device according to the present invention includes a charging device main body including a charging power transmission coil, a portable device including a charging power receiving coil, and the main body for detachably mounting the portable device. A non-contact power transmission device comprising a support base formed in part and transmitting power from the power transmission coil to the power receiving coil in a non-contact manner using electromagnetic induction, wherein the portable device includes a permanent magnet and an infrared light emitting element. And a support device provided with a magnetic field detecting element at a position facing the permanent magnet and a light receiving element at a position facing the infrared light emitting element, and the charging device includes the magnetic field detecting element as a magnetic field of the permanent magnet. And a control circuit that continuously oscillates when the light receiving element detects light from the infrared light emitting element, and transmits power from the power transmitting coil to the power receiving coil.
Further, the magnetic field detection element is a Hall IC incorporating a Hall element, the infrared light emitting element is a light emitting diode, and the light receiving element is a phototransistor. In addition, a light receiving element or an infrared light emitting element is arranged at the center of the power transmission coil and the power reception coil.

  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, the magnetic field detection element and the permanent magnet And the relationship between the light receiving element and the infrared light emitting element, the power transmission is controlled from the power transmission coil to the power reception coil by using a plurality of authentication means. Therefore, the danger of heat generation can be prevented. Further, when no portable device is placed, it is economical because it is a weak power necessary for driving only the magnetic field detecting element. Further, on the mobile device side, a reliable authentication can be performed with a weak power by using a small and light permanent magnet or an infrared light emitting element. Further, by arranging the infrared light emitting element or the light receiving element at the center of the power transmission coil and the power reception coil, the positional relationship between the power transmission coil and the power reception coil for the position authentication of the portable device and reliable power transmission can be obtained.

  Hereinafter, the non-contact power transmission apparatus of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a configuration diagram showing an embodiment of a non-contact power transmission apparatus according to the present invention.
FIG. 1A is a configuration diagram in which a portable device is mounted on the charging device main body, and FIG. 1B is a layout view seen from the back of the portable device.
The non-contact power transmission device shown in FIG. 1 includes a portable device 20 having a built-in charging coil L2 and a support base 11 having a built-in charging power transmission coil L1 for detachably mounting the portable device 20. And a charging device main body 10 provided.

As shown in FIG. 1B, the portable device 20 is provided with a power receiving coil L2, a light emitting diode 3b as an infrared light emitting element on the back side, and a permanent magnet 4b on the bottom side. The power receiving coil L2 is a flat air-core coil, and a light emitting diode 3b is provided at the center thereof.

As shown in FIG. 1A, the charging device main body 10 is provided with a support base 11 that holds the mobile device 20 in an inclined state. Inside the support base 11, a power receiving coil L <b> 2 provided on the mobile device 20 and A power transmission coil L1 and a phototransistor 3a as a light receiving element are provided at a position facing the light emitting diode 3b, and a Hall IC 4a made of a magnetic detection element is provided at a position facing the permanent magnet 4b. The power transmission coil L1 is formed of a flat air-core coil like the power reception coil L2, and a phototransistor 3a is disposed at the center thereof.

The distance between the power transmission coil L1, the phototransistor 3a, the Hall IC 4a (power transmission side) and the power reception coil L2, the light emitting diode 3b, and the permanent magnet 4b (power reception side) is the sum of the thickness of the casing of the portable device and the thickness of the casing of the support base. Dimensions. Further, between the light emitting diode and the phototransistor, light transmitting glass, transparent resin, or space is used. Furthermore, the casing between the power transmission coil, Hall IC, power reception coil, and permanent magnet is made of a material that does not disturb the magnetic field. For example, it is made of a resin excluding metal.
The air-core coil can be made lighter, thinner and smaller by using a flat shape in which an insulating coating wire is wound around a spiral and fixed with an adhesive or a fusion agent. Note that, when light weight and thinning are not a problem, winding may be performed on a bobbin or the like, and an infrared light emitting element or a light receiving element may be disposed at the center.

Next, the circuit configuration of the contactless power transmission device of the present invention will be described.
FIG. 2 is a block diagram illustrating a circuit configuration of the non-contact power transmission apparatus according to claim 1.
In the non-contact power transmission apparatus shown in FIG. 2, a charging power transmission coil L <b> 1 and a power transmission circuit 1 are connected in series to a charging apparatus body 10. The control circuit 2 turns the power transmission circuit 1 on and off by a detection signal of the Hall IC 4a including a Hall element as a magnetic field detection element and a detection signal of the phototransistor 3a as a light detection element.

  The portable device 20 includes a power receiving coil L2 that receives power from the power transmitting coil L1 by electromagnetic induction and a rectifying / smoothing circuit 5, a charge control circuit 6 that charges the secondary battery B, and other main circuits. (Not shown). Further, in the portable device 20, a permanent magnet 4b and a light emitting diode 3b which is an infrared light emitting element are incorporated in a position facing the Hall IC 4a incorporated in the support base 11 which is the charging device body 10 and the phototransistor 3a.

  When the Hall IC 4a incorporated in the support base 11 of the charger body 10 and the permanent magnet 4b in which the phototransistor 3a is incorporated in the portable device and the light emitting diode 3b are close to each other, that is, the portable device 20 is in a predetermined state on the support base 11. The Hall IC 4a detects the magnetic field of the permanent magnet 4b, and the phototransistor 3a detects the light of the light emitting diode 3b and applies the signal to the control circuit 2 so that the control circuit 2 The power transmission circuit 1 is turned on / off to supply power from the power transmission coil L1 to the power reception coil L2, and the secondary battery B built in through the smoothing circuit 5 and the charge control circuit 6 is charged.

FIG. 3 is a block diagram illustrating a circuit configuration of the non-contact power transmission apparatus according to claim 2.
The difference from FIG. 2 is that the operation of the control circuit 2 is made different depending on the detection signal of the Hall IC 4a and the phototransistor 3a incorporated in the support base 11 of the charger body 10.
The control circuit 2 includes a power switch circuit 2a, a pulse generation circuit 2b, and an intermittent / continuous switching circuit 2c. As an operation, when the portable device 20 is correctly placed on the support base 11 in a predetermined state, a signal obtained by detecting the magnetic field of the permanent magnet 4b by the Hall IC 4a is a power switch circuit 2a of the control circuit 2, a pulse generation circuit 2b, The operation of the power transmission circuit 1 is set to intermittent operation via the intermittent / continuous switching circuit 2c, and the received power of the portable device 20 emits light with operating power that the light emitting diode 3b can emit light (set to weak power that can emit light). ). When the light emitting diode 3b emits light and the phototransistor 3a of the charger body 10 detects the light, the control circuit 2 supplies the signal to the intermittent / continuous switching circuit 2c of the control circuit 2 so that the control circuit 2 is a power transmission circuit. A function for shifting the operation of 1 to a continuous operation is added. Since other operations are the same as those described above, description thereof will be omitted.

  Here, for example, when a metal piece such as a coin adheres to the support base, a gap is formed between the support base 11 and the mobile device 20 due to the attachment, that is, the mobile device floats, and the Hall IC becomes a permanent magnet. When the magnetic field cannot be detected, power is not transmitted from the charger body to the portable device. Even if the Hall IC can detect the magnetic field of the permanent magnet, power transmission by continuous operation (in a normal state) is not performed unless the phototransistor can detect light.

  Thus, in the non-contact power transmission device according to the present invention, by operating the power transmission circuit by the control circuit combining the Hall IC and the permanent magnet, the phototransistor and the light emitting diode, without supplying unnecessary power, No heat is generated by metal pieces. Further, by using a flat air-core coil for the power transmission coil and the power reception coil and arranging a phototransistor or a light emitting diode at the center thereof, it is possible to efficiently perform location authentication and power transmission of the portable device. 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 is reduced, so about two sets are preferred, and the circuit configuration and application Depending on the case, the number of sets may be further increased.

Next, the Hall IC used above is light and thin with a 3mm square and a heat of about 1mm. 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, the positional relationship between the Hall IC and the phototransistor and the permanent magnet and the light emitting diode is two-dimensionally arranged as shown in FIG. 1, but it may be the bottom surface. It is more preferable to make the relationship less risk of malfunction.

  4A, the Hall IC includes a Hall element 30, an amplifier 31, a Schmitt trigger circuit 32, a power supply Vcc, an output 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. 4B 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, a self-excited oscillation circuit or another example oscillation circuit may be used as the power transmission circuit of the charging device body.

The block diagram (a) which shows one Example of the non-contact electric power transmission apparatus which concerns on this invention, and the arrangement | positioning figure seen from the back surface. 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 Configuration diagram showing Hall IC (a) and graph showing magnetoelectric conversion characteristics (b) Configuration diagram showing a conventional non-contact power transmission device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Charging apparatus main body 11 Support stand 20 Portable apparatus 1 Power transmission circuit 2 Control circuit 3a Phototransistor 3b Light emitting diode 4a Hall IC
4b Permanent magnet 5 Rectification smoothing circuit 6 Charging control circuit L1 Power transmission coil L2 Power reception coil B Secondary battery

Claims (4)

A charging device main body including a charging power transmission coil, a portable device including a charging power receiving coil, and a support base formed on a part of the main body for detachably mounting the portable device. In the non-contact power transmission device that non-contact power transmission using electromagnetic induction from the power transmission coil to the power receiving coil,
The portable device comprising a permanent magnet and an infrared light emitting element, and a magnetic field detecting element at a position facing the permanent magnet, and the support base provided with a light receiving element at a position facing the infrared light emitting element, The charging device includes a control circuit that intermittently oscillates when the magnetic field detection element detects the magnetic field of the permanent magnet and continuously oscillates when the light receiving element detects light from the infrared light emitting element, and A non-contact power transmission device that transmits power to a power receiving coil. 2. The non-contact power transmission apparatus according to claim 1, wherein the magnetic field detection element is formed of a Hall IC including a Hall element, the infrared light emitting element is a light emitting diode, and the light receiving element is a phototransistor. . The non-contact power transmission device according to claim 1 , wherein a light receiving element or an infrared light emitting element is disposed in a central portion of the power transmission coil and the power reception coil. The non-contact power transmission device according to claim 3, wherein the power transmission coil and the power reception coil are flat air-core coils.

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