JPWO2007138670A1 - AC adapter and portable terminal device - Google Patents

Abstract

An object of the present invention is that a portable terminal device having a communication function is required to be equipped with various applications such as radio, television, wireless LAN, Bluetooth, RFID, etc. as the communication function expands. Stable communication or reception is performed using an AC adapter connected to the apparatus. In the present invention, by connecting (inserting) the connector 11 of the AC adapter 50 to the mobile terminal device 60, the antenna is changed from the internal antenna 71 of the mobile terminal device to the external antenna (code antenna) using the cord 12 of the AC adapter 50. By switching and changing the position of the ferrite 13, the antenna can be tuned according to the target frequency, and stable communication or reception can be ensured.

Description

  The present invention relates to an AC adapter, and a portable terminal device provided with a connector connected to the AC adapter and a communication function.

Conventionally, AC adapters are used as power supply means for charging secondary batteries in addition to supplying power to electronic devices. Specific examples include power supplies for liquid crystal monitors of personal computers and power supplies for charging electronic devices equipped with secondary batteries such as mobile phones, digital cameras, video movies, and notebook computers. Further, with the miniaturization of the AC adapter, the switching power supply method has become mainstream.
FIG. 10 shows an example of a conventional AC adapter for a mobile phone. The AC adapter 100 includes a connector unit 101 that is connected to a mobile phone, a cord 102, an AC / DC conversion unit 103, and an AC plug 104 that is plugged into an outlet.

By the way, for example, in the FM radio, a technique is known in which the antenna of the FM radio main body is not required by using the cord of the AC adapter as the FM dedicated antenna (for example, see Patent Document 1). Also, in a radio receiver equipped with a power supply base, when the radio receiver is mounted on the power supply base, the radio receiver and the external antenna terminal of the power supply base are coupled by inductive coupling, and the AC adapter is connected to the antenna line. A technique is also known in which power is supplied to a high-frequency amplifier built in an external antenna so that power is superimposed (see, for example, Patent Document 2).
JP-A-62-235825 Japanese Patent Laid-Open No. 2004-363638 (page 10, FIG. 4)

  However, with the technique described in Patent Document 1, the frequency band is dedicated to FM and cannot cope with a wideband frequency. Further, since the entire cord of the AC adapter is used as an antenna, the frequency cannot be adjusted. In particular, recent cellular phones have been developed that are equipped with receivers such as AM, FM, and TV, and antennas in a wide frequency band are required.

  Moreover, in the technique described in Patent Document 2, it is possible to cope with a broadband frequency by using an external antenna connected to the external antenna terminal of the power supply base. However, the device described in Patent Document 2 needs to prepare an external antenna and cannot easily enjoy broadcast reception.

  On the other hand, in a mobile terminal device such as a mobile phone, the physical installation space of the antenna is limited due to the downsizing of the device. In addition, with an emphasis on design, mobile phones and other types of antennas with built-in antennas are increasing, and it is becoming a tough condition to improve antenna performance. Furthermore, considering the widening of communication frequencies such as dual band and triple band for effective frequency utilization, a plurality of antennas are required. Further, the communication antenna and the broadcast receiving antenna are required to operate simultaneously, and interference and isolation between the communication antenna and the broadcast receiving antenna become a problem. Furthermore, there are many things that block radio waves in buildings, and the reception electric field is attenuated, and stable reception may not be possible.

  The present invention has been made to solve such a problem. By operating the AC adapter cord as a multi-frequency antenna, the AC adapter can be connected stably without connecting a dedicated external antenna. It is an object of the present invention to provide an AC adapter and a portable terminal device that can ensure reception or communication.

In order to achieve the above object, an AC adapter according to the present invention includes a connector portion that is electrically connected to a portable terminal device, a plug that can be connected to an AC outlet, a conversion portion that converts alternating current into direct current, and the connector. A cord connecting between the converter and the converter, and a ferrite provided movably on the cord to a required position according to the frequency to be tuned, and the electrical length is changed according to the moving position of the ferrite, And an external antenna using the cord.
With this configuration, regardless of whether or not the AC adapter is connected to an AC outlet, the antenna can be switched to an external antenna using the cord of the AC adapter by connecting the AC adapter to the portable terminal device. . Also, with this configuration, it is possible to tune to the optimum frequency by moving the ferrite on the cord and changing the frequency of the standing wave on the cord.

  In the AC adapter of the present invention, the cord portion is provided with a stopper for limiting the range in which the ferrite can move in accordance with the upper and lower limits of the operating frequency. With this configuration, it is possible to prevent the movement of the ferrite from deviating from the operating frequency range.

  In the AC adapter of the present invention, an identification display means for identifying the band of the used frequency is provided in the code portion. With this configuration, it is possible to easily perform tuning for each frequency band used.

  In the AC adapter of the present invention, ferrite is fixedly provided at a position immediately after the conversion unit. With this configuration, it is possible to remove noise from the conversion unit.

  The mobile terminal device of the present invention is a mobile terminal device having an internal antenna and a connector to which any one of the above AC adapters can be connected, and detecting that the AC adapter is connected to the connector An antenna switching unit that switches the antenna from the internal antenna to the external antenna on the AC adapter side, and a control unit that controls the antenna switching unit based on a signal detected by the detection unit. When the AC adapter is connected, the antenna switching unit switches from the internal antenna to the external antenna on the AC adapter side.

  According to the present invention, in an AC adapter that charges and energizes a mobile terminal device, when the cord portion is used as an antenna, the ferrite whose electrical length changes according to the moving position is tuned on the cord. By providing a movable position to a required position according to the power frequency, it is possible to easily tune to a desired frequency.

1 is an external perspective view of an AC adapter according to a first embodiment of the present invention. Frequency characteristics diagram of ferrite provided on the AC adapter A perspective view showing a specific shape of the movable ferrite The perspective view which shows the detachable ferrite which is the modification of the ferrite External appearance perspective view of the AC adapter which concerns on the 2nd Embodiment of this invention External appearance perspective view of the AC adapter which concerns on the 3rd Embodiment of this invention The external appearance perspective view of the AC adapter which concerns on the 4th Embodiment of this invention The circuit block diagram of the principal part of the portable terminal device which concerns on the 5th Embodiment of this invention. The block diagram which shows the whole structure of the portable terminal device External perspective view showing a conventional AC adapter

Explanation of symbols

10, 20, 30, 40, 50 AC adapter 11, 76 connector 12 cord (external antenna)
13, 13A, 13B Ferrite 14 AC / DC converter 15 AC plug 21 High frequency side stopper (stopper)
22 Low frequency side stopper (stopper)
31 High frequency marker (identification display)
32 Marker for mid range (identification display means)
33 Low frequency marker (identification display)
41 Noise filter 60 Mobile terminal device 61, 66 High frequency cutoff coil 62 GND
63 Capacitor 64 Antenna feed point 65 + side power supply 71 Antenna (internal antenna)
72 power supply unit 73 antenna switching unit 74 antenna switching control unit 75 power antenna separation unit 77 AC adapter insertion detection unit

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is an external view of an AC adapter 10 according to the first embodiment of the present invention.
The AC adapter 10 is configured to be connected to a mobile terminal device not shown, and includes a connector unit 11, a cord 12, a ferrite 13, an AC / DC conversion unit 14, and an AC plug 15. .

  The AC / DC conversion unit 14 and the AC plug 15 have an integral structure, and a DC power output is supplied to the connector unit 11 by a cord 12. The ferrite 13 has a structure that can freely move on the cord 12. Further, the ferrite 13 has a characteristic of blocking high frequency. For this reason, it is possible to create an arbitrary electrical length at a high frequency by inserting the ferrite 13 into a cord 12 having an arbitrary electrical length (hereinafter also referred to as “code antenna”).

  Next, FIG. 2 shows frequency characteristics of a general ferrite. The frequency characteristics of this ferrite can be changed by an appropriate material according to the use frequency. For example, in the ferrite exemplified in FIG. 2, A is 1 to 20 MHz, B is 30 to 250 MHz, and C is 200 to 2000 MHz. This frequency indicates a frequency at which power is attenuated by the ferrite.

  The frequency when the AC adapter cord is used as an antenna is 76 to 90 MHz for FM radio, 90 to 222 MHz for 1 to 12 channels for VHF TV, and 470 to 770 MHz for 13 to 62 channels for UHF TV. It becomes. Therefore, the total length of the cord as the antenna is (1/4) λ, 0.99 to 0.83 m for FM radio, 0.83 to 0.34 m for VHF television, and UHF television Is 0.16 to 0.1 m.

  For example, when the cord of the AC adapter is an FM radio antenna, the ferrite of type B in FIG. 2 is used, and the dimension A in FIG. 1 is 0.99 to 0.83 m. When the antenna of the VHF television is used, the ferrite of type B in FIG. 2 is used, and the dimension A in FIG. 1 is 0.83 to 0.34 m. When the antenna of a UHF television is used, the type C ferrite of FIG. 2 is used, and the dimension A of FIG. 1 is 0.16 to 0.1 m.

  Further, by adopting a type that can be divided into the ferrite 13, it is possible to exchange the ferrite according to the frequency band to be used. Depending on the type of ferrite, it is possible to produce a ferrite that covers the types B and C in FIG. 2 with a single ferrite. By using such a ferrite, an antenna that can cover FM to UHF with a cord of an AC adapter can be manufactured.

  Note that the ferrite that can move on the cord of this embodiment has a structure and dimensions that cannot be easily moved during the operation of tuning the frequency, so it can be moved only by applying force. It is configured to be able to.

  For example, FIG. 3 and FIG. 4 are specific structural examples of the ferrite 13 that can move on the cord. The ferrite 13A of the type shown in FIG. 3 can move on the cord 12, but cannot be removed from the cord 12. On the other hand, the ferrite 13B of the type shown in FIG. 4 is a split type. For example, the ferrite 13B can move on the cord 12 if they are joined together, and can be removed from the cord 12 if separated into two pieces. Is possible. Further, as another type, for example, a structure that can move on the cord 12 by assembling a sheet shape when removed into a cylindrical shape may be used.

(Second Embodiment)
FIG. 5 is an external view of an AC adapter 20 according to the second embodiment of the present invention. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals to avoid redundant description.
The AC adapter 20 of the present embodiment includes a high frequency side stopper 106 and a low frequency side stopper 107 in addition to the connector portion 11, the cord 12, the ferrite 13, the AC / DC conversion portion 14, and the AC plug 15. And.

  Also in the present embodiment, as in the first embodiment, it is possible to create an arbitrary electrical length at a high frequency by inserting the ferrite 13 into the cord 12 having an arbitrary electrical length. Furthermore, in the present embodiment, unlike the first embodiment, a high frequency side stopper 21 and a low frequency side stopper 22 are provided.

The high frequency side stopper 21 and the low frequency side stopper 22 can clarify the tuning frequency range. For example, it is 76 to 90 MHz for FM radio, 90 to 222 MHz for 1 to 12 channels for VHF television, and 470 to 770 MHz for 13 to 62 channels for UHF television.
Therefore, when the corresponding band is from FM to UHF, the high frequency side stopper 21 has a cutoff frequency of 770 MHz, and the corresponding electrical length (the length of the antenna to be tuned is (1/4) λ). For example, 0.1 m). The low frequency side stopper 22 has a cutoff frequency of 76 MHz and is fixed at a corresponding electrical length (0.99 m if the length of the antenna to be tuned is (1/4) λ). . The electrical length is a distance from a feeding point of an antenna inside an electronic device (not shown) to which the AC adapter 20 is connected.

  Thereby, according to this embodiment, it can comprise so that it cannot tune to a frequency lower than 76 MHz and a frequency higher than 770 MHz.

(Third embodiment)
FIG. 6 is an external view of an AC adapter 30 according to the third embodiment of the present invention. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals to avoid redundant description.
The AC adapter 30 according to the present embodiment includes a connector unit 11, a cord 12, a ferrite 13, an AC / DC conversion unit 14, an AC plug 15, a high frequency side stopper 21, and a low frequency side stopper 22. Furthermore, a high-frequency marker 31, a mid-frequency marker 32, and a low-frequency marker 33 are provided as identification display means for identifying the band of the used frequency.

  That is, also in this embodiment, it is possible to create an arbitrary electrical length at a high frequency by inserting the ferrite 13 into the cord 12 having an arbitrary electrical length, and the high frequency side stopper 21 and the low frequency side stopper 22. Thus, it is possible to freely set the range between the lower limit frequency and the upper limit frequency of the corresponding frequency.

Further, in the present embodiment, unlike the first and second embodiments, the positions for moving the ferrite 13 to tune the frequency are selected from the corresponding frequencies such as the FM band, the VHF band, and the UHF band. Each position (or each band) is calculated and searched in advance, and this position is displayed as a guide by a marker that is an identification display means.
As a specific example, for example, the high band marker 31 corresponds to the FM band (76 to 90 MHz), the mid band marker 32 corresponds to the VHF band (90 to 222 MHz), and the low band marker 33 corresponds to the UHF band (470 to 770 MHz). I am letting.
As a result, the frequency can be easily tuned by using the markers 31 to 33 as clues.

(Fourth embodiment)
FIG. 7 is an external view of an AC adapter 40 according to the fourth embodiment of the present invention.
As a feature of the present embodiment, a noise filter 41 is mounted in the AC adapters 10 to 30 of the first to third embodiments.

  The noise filter 41 is for removing noise at the switching oscillation frequency used in the AC / DC converter 14. Moreover, it is effective to place it at a position close to the output side of the AC / DC converter 14 as the mounting position. In particular, since the cord 12 is an antenna, harmonics of the switching oscillation frequency are likely to be mixed into the front end portion of the mobile terminal device (receiver) (not shown) via the antenna, so noise must be removed. Because it is.

(Fifth embodiment)
FIG. 8 shows a circuit configuration of the main part when the AC adapter 50 according to the fifth embodiment of the present invention is connected to the mobile terminal device 60. The configuration of the AC adapter 50 according to this embodiment will be described later with reference to FIG. 9. Any of the AC adapters 10 to 40 according to the first to fourth embodiments described above may be used. It may be used.

In a state where the connector unit 11 is connected to the mobile terminal device 60, the cord 12 operates as an antenna.
The cord 12 normally has a coaxial structure, and uses an unillustrated outer side electric wire as an antenna. The outer side wire is usually used as the GND side. The outer wire is connected to the high-frequency cutoff coil 61 and terminated at the GND 62. If the frequency range in which the cord 12 is used as an antenna is 76 MHz to 770 MHz, for example, a high frequency current flowing to the GND 62 side can be blocked by using a coil of about 100 nH to 10 μH as the high frequency cutoff coil 61.

  Further, the electric wire on the outer side of the cord 12 is connected to the antenna feeding point 64 via the capacitor 63. The capacitor 64 plays a role of preventing destruction of the semiconductor element in the front end portion or the switch portion due to static electricity in addition to the direct current cut. If the frequency range in which the cord 12 is used as an antenna is, for example, 76 MHz to 770 MHz, the capacitor 63 of about 1000 pF to 0.01 μF can be used so that the corresponding frequency can pass through with almost no attenuation.

Further, the electric wire on the core wire side of the cord 12 is normally used as the power source 65 on the positive side. When the noise of the mobile terminal device 60 is superimposed on the core-side electric wire, the noise is capacitively coupled to the outer-side electric wire inside the cord 12, so the high-frequency cutoff coil 66 is also inserted on the core wire side.
Similarly to the high frequency cutoff coil 61, the high frequency cutoff coil 66 uses a coil of about 100 nH to 10 μH as the high frequency cutoff coil 66 when the frequency range is 76 MHz to 770 MHz. Prevent joining.

Next, FIG. 9 is a block diagram showing an overall configuration when the AC adapter 50 according to the fifth embodiment of the present invention is connected to the portable terminal device 60.
In the figure, an AC adapter 50 includes an AC / DC conversion unit 14, a connector 11 for connecting to a mobile terminal device 60, a cord antenna (external antenna) 12, and a ferrite 13.

  On the other hand, the mobile terminal device 60 includes an antenna (internal antenna) 71, a power supply unit 72, an antenna switching unit 73, an antenna switching control unit 74, a power supply antenna separation unit 75, a connector 76, and an AC adapter insertion detection. Part 77 and the like. The power supply antenna separation unit 75 constitutes a means for separating the internal antenna 71 and the power supply of the AC adapter 50 and the cord antenna 12 using the conductor of the cord sheath.

  When the AC adapter 50 is connected (inserted) to the connector 76 of the portable terminal device 60, this connection state is detected by the AC adapter insertion detection unit 77, the antenna switching control unit 74 operates the antenna switching unit 73, and the antenna Switching from the (internal antenna) 71 to the cord antenna (external antenna) 12 on the AC adapter side. That is, according to the present embodiment, the antenna of the mobile terminal device can be automatically switched from the antenna 71 to the cord antenna 12 simply by connecting the AC adapter 50 to the mobile terminal device 60.

  Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

  As described above, the AC adapter and the mobile terminal device according to the present invention facilitate stable communication by providing the antenna function in the AC adapter connected as a power supply to the mobile terminal device body having a communication function. This is useful for mobile phones, PHS, PDAs, portable radios, portable televisions, wireless LANs, Bluetooth, RFIDs, and the like that can be realized in the future.

  The present invention relates to an AC adapter, and a portable terminal device provided with a connector connected to the AC adapter and a communication function.

Conventionally, AC adapters are used as power supply means for charging secondary batteries in addition to supplying power to electronic devices. Specific examples include power supplies for liquid crystal monitors of personal computers and power supplies for charging electronic devices equipped with secondary batteries such as mobile phones, digital cameras, video movies, and notebook computers. Further, with the miniaturization of the AC adapter, the switching power supply method has become mainstream.
FIG. 10 shows an example of a conventional AC adapter for a mobile phone. The AC adapter 100 includes a connector unit 101 that is connected to a mobile phone, a cord 102, an AC / DC conversion unit 103, and an AC plug 104 that is plugged into an outlet.

By the way, for example, in the FM radio, a technique is known in which the antenna of the FM radio main body is not required by using the cord of the AC adapter as the FM dedicated antenna (for example, see Patent Document 1). Also, in a radio receiver equipped with a power supply base, when the radio receiver is mounted on the power supply base, the radio receiver and the external antenna terminal of the power supply base are coupled by inductive coupling, and the AC adapter is connected to the antenna line. A technique is also known in which power is supplied to a high-frequency amplifier built in an external antenna so that power is superimposed (see, for example, Patent Document 2).
JP-A-62-235825 Japanese Patent Laid-Open No. 2004-363638 (page 10, FIG. 4)

  However, with the technique described in Patent Document 1, the frequency band is dedicated to FM and cannot cope with a wideband frequency. Further, since the entire cord of the AC adapter is used as an antenna, the frequency cannot be adjusted. In particular, recent cellular phones have been developed that are equipped with receivers such as AM, FM, and TV, and antennas in a wide frequency band are required.

  Moreover, in the technique described in Patent Document 2, it is possible to cope with a broadband frequency by using an external antenna connected to the external antenna terminal of the power supply base. However, the device described in Patent Document 2 needs to prepare an external antenna and cannot easily enjoy broadcast reception.

  On the other hand, in a mobile terminal device such as a mobile phone, the physical installation space of the antenna is limited due to the downsizing of the device. In addition, with an emphasis on design, mobile phones and other types of antennas with built-in antennas are increasing, and it is becoming a tough condition to improve antenna performance. Furthermore, considering the widening of communication frequencies such as dual band and triple band for effective frequency utilization, a plurality of antennas are required. Further, the communication antenna and the broadcast receiving antenna are required to operate simultaneously, and interference and isolation between the communication antenna and the broadcast receiving antenna become a problem. Furthermore, there are many things that block radio waves in buildings, and the reception electric field is attenuated, and stable reception may not be possible.

The present invention has been made to solve such a problem. By operating the AC adapter cord as a multi-frequency antenna, the AC adapter can be connected stably without connecting a dedicated external antenna. It is an object of the present invention to provide an AC adapter and a portable terminal device that can ensure reception or communication.

In order to achieve the above object, an AC adapter according to the present invention includes a connector portion that is electrically connected to a portable terminal device, a plug that can be connected to an AC outlet, a conversion portion that converts alternating current into direct current, and the connector. A cord connecting between the converter and the converter, and a ferrite provided movably on the cord to a required position according to the frequency to be tuned, and the electrical length is changed according to the moving position of the ferrite, And an external antenna using the cord.
With this configuration, regardless of whether or not the AC adapter is connected to an AC outlet, the antenna can be switched to an external antenna using the cord of the AC adapter by connecting the AC adapter to the portable terminal device. . Also, with this configuration, it is possible to tune to the optimum frequency by moving the ferrite on the cord and changing the frequency of the standing wave on the cord.

  In the AC adapter of the present invention, the cord portion is provided with a stopper for limiting the range in which the ferrite can move in accordance with the upper and lower limits of the operating frequency. With this configuration, it is possible to prevent the movement of the ferrite from deviating from the operating frequency range.

  In the AC adapter of the present invention, an identification display means for identifying the band of the used frequency is provided in the code portion. With this configuration, it is possible to easily perform tuning for each frequency band used.

  In the AC adapter of the present invention, ferrite is fixedly provided at a position immediately after the conversion unit. With this configuration, it is possible to remove noise from the conversion unit.

  The mobile terminal device of the present invention is a mobile terminal device having an internal antenna and a connector to which any one of the above AC adapters can be connected, and detecting that the AC adapter is connected to the connector An antenna switching unit that switches the antenna from the internal antenna to the external antenna on the AC adapter side, and a control unit that controls the antenna switching unit based on a signal detected by the detection unit. When the AC adapter is connected, the antenna switching unit switches from the internal antenna to the external antenna on the AC adapter side.

  According to the present invention, in an AC adapter that charges and energizes a mobile terminal device, when the cord portion is used as an antenna, the ferrite whose electrical length changes according to the moving position is tuned on the cord. By providing a movable position to a required position according to the power frequency, it is possible to easily tune to a desired frequency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is an external view of an AC adapter 10 according to the first embodiment of the present invention.
The AC adapter 10 is configured to be connected to a mobile terminal device not shown, and includes a connector unit 11, a cord 12, a ferrite 13, an AC / DC conversion unit 14, and an AC plug 15. .

The AC / DC conversion unit 14 and the AC plug 15 have an integral structure, and a DC power output is supplied to the connector unit 11 by a cord 12. The ferrite 13 has a structure that can freely move on the cord 12. Further, the ferrite 13 has a characteristic of blocking high frequency. For this reason, it is possible to create an arbitrary electrical length at a high frequency by inserting the ferrite 13 into a cord 12 having an arbitrary electrical length (hereinafter also referred to as “code antenna”).

  Next, FIG. 2 shows frequency characteristics of a general ferrite. The frequency characteristics of this ferrite can be changed by an appropriate material according to the use frequency. For example, in the ferrite exemplified in FIG. 2, A is 1 to 20 MHz, B is 30 to 250 MHz, and C is 200 to 2000 MHz. This frequency indicates a frequency at which power is attenuated by the ferrite.

  The frequency when the AC adapter cord is used as an antenna is 76 to 90 MHz for FM radio, 90 to 222 MHz for 1 to 12 channels for VHF TV, and 470 to 770 MHz for 13 to 62 channels for UHF TV. It becomes. Therefore, the total length of the cord as the antenna is (1/4) λ, 0.99 to 0.83 m for FM radio, 0.83 to 0.34 m for VHF television, and UHF television Is 0.16 to 0.1 m.

  For example, when the cord of the AC adapter is an FM radio antenna, the ferrite of type B in FIG. 2 is used, and the dimension A in FIG. 1 is 0.99 to 0.83 m. When the antenna of the VHF television is used, the ferrite of type B in FIG. 2 is used, and the dimension A in FIG. 1 is 0.83 to 0.34 m. When the antenna of a UHF television is used, the type C ferrite of FIG. 2 is used, and the dimension A of FIG. 1 is 0.16 to 0.1 m.

  Further, by adopting a type that can be divided into the ferrite 13, it is possible to exchange the ferrite according to the frequency band to be used. Depending on the type of ferrite, it is possible to produce a ferrite that covers the types B and C in FIG. 2 with a single ferrite. By using such a ferrite, an antenna that can cover FM to UHF with a cord of an AC adapter can be manufactured.

  Note that the ferrite that can move on the cord of this embodiment has a structure and dimensions that cannot be easily moved during the operation of tuning the frequency, so it can be moved only by applying force. It is configured to be able to.

  For example, FIG. 3 and FIG. 4 are specific structural examples of the ferrite 13 that can move on the cord. The ferrite 13A of the type shown in FIG. 3 can move on the cord 12, but cannot be removed from the cord 12. On the other hand, the ferrite 13B of the type shown in FIG. 4 is a split type. For example, the ferrite 13B can move on the cord 12 if they are joined together, and can be removed from the cord 12 if separated into two pieces. Is possible. Further, as another type, for example, a structure that can move on the cord 12 by assembling a sheet shape when removed into a cylindrical shape may be used.

(Second Embodiment)
FIG. 5 is an external view of an AC adapter 20 according to the second embodiment of the present invention. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals to avoid redundant description.
The AC adapter 20 of the present embodiment includes a high frequency side stopper 106 and a low frequency side stopper 107 in addition to the connector portion 11, the cord 12, the ferrite 13, the AC / DC conversion portion 14, and the AC plug 15. And.

Also in the present embodiment, as in the first embodiment, the ferrite 13 is added to the cord 12 having an arbitrary electrical length.
It becomes possible to create an arbitrary electrical length at a high frequency by inserting. Furthermore, in the present embodiment, unlike the first embodiment, a high frequency side stopper 21 and a low frequency side stopper 22 are provided.

The high frequency side stopper 21 and the low frequency side stopper 22 can clarify the tuning frequency range. For example, it is 76 to 90 MHz for FM radio, 90 to 222 MHz for 1 to 12 channels for VHF television, and 470 to 770 MHz for 13 to 62 channels for UHF television.
Therefore, when the corresponding band is from FM to UHF, the high frequency side stopper 21 has a cutoff frequency of 770 MHz, and the corresponding electrical length (the length of the antenna to be tuned is (1/4) λ). For example, 0.1 m). The low frequency side stopper 22 has a cutoff frequency of 76 MHz and is fixed at a corresponding electrical length (0.99 m if the length of the antenna to be tuned is (1/4) λ). . The electrical length is a distance from a feeding point of an antenna inside an electronic device (not shown) to which the AC adapter 20 is connected.

  Thereby, according to this embodiment, it can comprise so that it cannot tune to a frequency lower than 76 MHz and a frequency higher than 770 MHz.

(Third embodiment)
FIG. 6 is an external view of an AC adapter 30 according to the third embodiment of the present invention. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals to avoid redundant description.
The AC adapter 30 according to the present embodiment includes a connector unit 11, a cord 12, a ferrite 13, an AC / DC conversion unit 14, an AC plug 15, a high frequency side stopper 21, and a low frequency side stopper 22. Furthermore, a high-frequency marker 31, a mid-frequency marker 32, and a low-frequency marker 33 are provided as identification display means for identifying the band of the used frequency.

  That is, also in this embodiment, it is possible to create an arbitrary electrical length at a high frequency by inserting the ferrite 13 into the cord 12 having an arbitrary electrical length, and the high frequency side stopper 21 and the low frequency side stopper 22. Thus, it is possible to freely set the range between the lower limit frequency and the upper limit frequency of the corresponding frequency.

Further, in the present embodiment, unlike the first and second embodiments, the positions for moving the ferrite 13 to tune the frequency are selected from the corresponding frequencies such as the FM band, the VHF band, and the UHF band. Each position (or each band) is calculated and searched in advance, and this position is displayed as a guide by a marker that is an identification display means.
As a specific example, for example, the high band marker 31 corresponds to the FM band (76 to 90 MHz), the mid band marker 32 corresponds to the VHF band (90 to 222 MHz), and the low band marker 33 corresponds to the UHF band (470 to 770 MHz). I am letting.
As a result, the frequency can be easily tuned by using the markers 31 to 33 as clues.

(Fourth embodiment)
FIG. 7 is an external view of an AC adapter 40 according to the fourth embodiment of the present invention.
As a feature of the present embodiment, a noise filter 41 is mounted in the AC adapters 10 to 30 of the first to third embodiments.

The noise filter 41 is for removing noise at the switching oscillation frequency used in the AC / DC converter 14. Moreover, it is effective to place it at a position close to the output side of the AC / DC converter 14 as the mounting position. In particular, since the cord 12 is an antenna, harmonics of the switching oscillation frequency are likely to be mixed into the front end portion of the mobile terminal device (receiver) (not shown) via the antenna, so noise must be removed. Because it is.

(Fifth embodiment)
FIG. 8 shows a circuit configuration of the main part when the AC adapter 50 according to the fifth embodiment of the present invention is connected to the mobile terminal device 60. The configuration of the AC adapter 50 according to this embodiment will be described later with reference to FIG. 9. Any of the AC adapters 10 to 40 according to the first to fourth embodiments described above may be used. It may be used.

In a state where the connector unit 11 is connected to the mobile terminal device 60, the cord 12 operates as an antenna.
The cord 12 normally has a coaxial structure, and uses an unillustrated outer side electric wire as an antenna. The outer side wire is usually used as the GND side. The outer wire is connected to the high-frequency cutoff coil 61 and terminated at the GND 62. If the frequency range in which the cord 12 is used as an antenna is 76 MHz to 770 MHz, for example, a high frequency current flowing to the GND 62 side can be blocked by using a coil of about 100 nH to 10 μH as the high frequency cutoff coil 61.

  Further, the electric wire on the outer side of the cord 12 is connected to the antenna feeding point 64 via the capacitor 63. The capacitor 64 plays a role of preventing destruction of the semiconductor element in the front end portion or the switch portion due to static electricity in addition to the direct current cut. If the frequency range in which the cord 12 is used as an antenna is, for example, 76 MHz to 770 MHz, the capacitor 63 of about 1000 pF to 0.01 μF can be used so that the corresponding frequency can pass through with almost no attenuation.

Further, the electric wire on the core wire side of the cord 12 is normally used as the power source 65 on the positive side. When the noise of the mobile terminal device 60 is superimposed on the core-side electric wire, the noise is capacitively coupled to the outer-side electric wire inside the cord 12, so the high-frequency cutoff coil 66 is also inserted on the core wire side.
Similarly to the high frequency cutoff coil 61, the high frequency cutoff coil 66 uses a coil of about 100 nH to 10 μH as the high frequency cutoff coil 66 when the frequency range is 76 MHz to 770 MHz. Prevent joining.

Next, FIG. 9 is a block diagram showing an overall configuration when the AC adapter 50 according to the fifth embodiment of the present invention is connected to the portable terminal device 60.
In the figure, an AC adapter 50 includes an AC / DC conversion unit 14, a connector 11 for connecting to a mobile terminal device 60, a cord antenna (external antenna) 12, and a ferrite 13.

  On the other hand, the mobile terminal device 60 includes an antenna (internal antenna) 71, a power supply unit 72, an antenna switching unit 73, an antenna switching control unit 74, a power supply antenna separation unit 75, a connector 76, and an AC adapter insertion detection. Part 77 and the like. The power supply antenna separation unit 75 constitutes a means for separating the internal antenna 71 and the power supply of the AC adapter 50 and the cord antenna 12 using the conductor of the cord sheath.

  When the AC adapter 50 is connected (inserted) to the connector 76 of the portable terminal device 60, this connection state is detected by the AC adapter insertion detection unit 77, the antenna switching control unit 74 operates the antenna switching unit 73, and the antenna Switching from the (internal antenna) 71 to the cord antenna (external antenna) 12 on the AC adapter side. That is, according to the present embodiment, the antenna of the mobile terminal device can be automatically switched from the antenna 71 to the cord antenna 12 simply by connecting the AC adapter 50 to the mobile terminal device 60.

  Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

  As described above, the AC adapter and the mobile terminal device according to the present invention facilitate stable communication by providing the antenna function in the AC adapter connected as a power supply to the mobile terminal device body having a communication function. This is useful for mobile phones, PHS, PDAs, portable radios, portable televisions, wireless LANs, Bluetooth, RFIDs, and the like that can be realized in the future.

1 is an external perspective view of an AC adapter according to a first embodiment of the present invention. Frequency characteristics diagram of ferrite provided on the AC adapter A perspective view showing a specific shape of the movable ferrite The perspective view which shows the detachable ferrite which is the modification of the ferrite External appearance perspective view of the AC adapter which concerns on the 2nd Embodiment of this invention External appearance perspective view of the AC adapter which concerns on the 3rd Embodiment of this invention The external appearance perspective view of the AC adapter which concerns on the 4th Embodiment of this invention The circuit block diagram of the principal part of the portable terminal device which concerns on the 5th Embodiment of this invention. The block diagram which shows the whole structure of the portable terminal device External perspective view showing a conventional AC adapter

Explanation of symbols

10, 20, 30, 40, 50 AC adapter 11, 76 connector 12 cord (external antenna)
13, 13A, 13B Ferrite 14 AC / DC converter 15 AC plug 21 High frequency side stopper (stopper)
22 Low frequency side stopper (stopper)
31 High frequency marker (identification display)
32 Marker for mid range (identification display means)
33 Low frequency marker (identification display)
41 Noise filter 60 Mobile terminal device 61, 66 High frequency cutoff coil 62 GND
63 Capacitor 64 Antenna feed point 65 + side power supply 71 Antenna (internal antenna)
72 power supply unit 73 antenna switching unit 74 antenna switching control unit 75 power antenna separation unit 77 AC adapter insertion detection unit

Claims (5)

A connector portion electrically connected to the portable terminal device;
A plug that can be connected to an AC outlet;
A converter for converting alternating current to direct current;
A cord connecting between the connector portion and the conversion portion;
To the required position according to the frequency to be tuned, the ferrite provided to be movable on the cord,
The electrical length changes according to the moving position of this ferrite, an external antenna using the cord,
An AC adapter.   The AC adapter according to claim 1, wherein the cord portion includes a stopper for limiting a range in which the ferrite can move in accordance with an upper limit and a lower limit of a use frequency.   The AC adapter according to claim 1, wherein identification code means for identifying a band of a used frequency is provided in the code portion.   The AC adapter according to claim 1, wherein a ferrite is fixedly provided at a position immediately after the conversion unit. A portable terminal device having an internal antenna and a connector to which the AC adapter according to any one of claims 1 to 4 can be connected,
A detection unit for detecting that the AC adapter is connected to the connector;
An antenna switching unit that switches the antenna from the internal antenna to the external antenna on the AC adapter side;
A control unit for controlling the antenna switching unit based on the signal detected by the detection unit;
Have
A portable terminal device configured such that when the AC adapter is connected, the antenna switching unit switches the internal antenna to the external antenna on the AC adapter side.

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