JP2013009469A - Non-contact power transmission system and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission system with a reinforced protection function of a transmission apparatus for prevention of a malfunction and an electronic apparatus capable of compactly storing the transmission apparatus and achieving little effect of noise.SOLUTION: A non-contact power transmission system includes a function that shuts down conduction of a first semiconductor switch 5 when the conduction time of a second semiconductor switch 6 exceeds a predetermined time, and an electronic apparatus includes the non-contact power transmission system.

Description

  The present invention relates to a non-contact power transmission system and an electronic device that enhance a protection function of a power transmission device to prevent malfunction.

  In recent years, with the miniaturization of electronic components, portable electronic devices typified by mobile phones and portable music players are becoming more and more popular due to the reduction in size and weight. Furthermore, in recent years, portable electronic devices have been made multifunctional and high-speed processing, and accordingly, the amount of power required for the portable electronic devices has been increasing. However, in general, portable electronic devices are not equipped with a dedicated adapter, but are driven by the power charged in the built-in secondary battery, and the secondary battery is charged each time the power of the secondary battery is insufficient. There are many things.

  In general, charging of a secondary battery of a portable electronic device is performed by bringing the charging terminal of the portable electronic device and the charging terminal of the charging stand (cradle) into contact with each other, electrically connecting them, and supplying power from the charging stand. The next battery was charged. However, in the charging method in which the charging terminals are connected in contact with each other, charging may not be possible due to contamination of the charging terminals or entry of foreign matter between the charging terminals. Thus, recently, the demand for contactless power supply using the principle of magnetic coupling, that is, a contactless power transmission device, has increased.

  In order to perform power transmission normally in the non-contact power transmission device, it is necessary to communicate information such as required power on the power receiving side and power transmission stoppage at the time of abnormality between the power transmission device and the power receiving device. For example, Patent Document 1 causes intermittent power transmission from a power transmission device to a power reception device, and within a predetermined time from the start of temporary power transmission, the power transmission device receives ID authentication information from the power reception device that received the temporary power transmission. When receiving and successfully authenticating the ID, the system executes normal power transmission from the power transmission device to the power reception device.

  Patent Document 2 starts power transmission from the power transmission coil via the control circuit of the power transmission side unit when detecting that the power reception side unit is placed on the support base, and receives power when the power reception coil receives power. An authentication signal is transmitted from the modulation circuit of the unit. The power transmission side unit includes a timer circuit that detects the authentication signal based on a voltage change of the power transmission coil, demodulates and collates the authentication signal by the demodulation circuit of the power transmission side unit, and controls power transmission stop and restart.

  Furthermore, when charging a portable electronic device in a non-contact power transmission device, generally, as in Patent Document 3, a power receiving device (mobile phone) is placed on a power transmission device (charger).

JP 2009-189231 A JP 2009-22122 A JP 2008-294385 A

  However, in the prior art, a semiconductor in which a malfunction of a circuit occurs due to the influence of some external EMI (Electro Magnetic Interference) during power transmission from the power transmission device to the power reception device, and a switching operation is performed for power transmission. The phenomenon that the gate conduction time becomes longer than the setting is observed. If the current is flowing for a long time and continues to flow, the same state as a power supply line short circuit occurs, which may cause problems such as semiconductor damage, circuit damage, and substrate burnout in the power transmission / reception device.

  This situation cannot be detected by the ID authentication system of Patent Document 1 or the authentication signal of Patent Document 2, and even if the malfunction occurs, it becomes clear after the occurrence of semiconductor damage, circuit damage, heat generation, etc. It is contents to do. Further, when the semiconductor in the power transmission / reception device is exposed to this phenomenon, there is a concern that the reliability characteristics are deteriorated and the product life is shortened. Therefore, there is a problem that some kind of protection function is required to prevent malfunction.

  Furthermore, an electronic device equipped with the non-contact power transmission system of Patent Document 3 requires a case for a power transmission device that houses a power transmission circuit and a power transmission coil. For this reason, there is a problem that a place for installation on a desk or the like is required, or a place for storing the case of the power transmission device itself is required to prevent loss.

  Therefore, the present invention provides a non-contact power transmission system in which a protection function of a power transmission device is strengthened to prevent malfunction, and an electronic device in which the power transmission device can be stored compactly in an electronic device and is less affected by noise. With the goal.

  In order to solve the above problems, the present invention provides a non-contact power transmission system having a function of cutting off the conduction of the first semiconductor switch when the conduction time of the second semiconductor switch exceeds a preset time. And an electronic device incorporating the same.

That is, according to the present invention, a power transmission device having a power transmission coil and a power reception device provided with a power reception coil that is magnetically coupled to the power transmission coil, the power transmission device and the power reception device are disposed in proximity to each other, A non-contact power transmission system that performs non-contact power transmission from the power transmission device to the power reception device and data communication between the power transmission device and the power reception device via a magnetic coupling between the power transmission coil and the power reception coil. There,
The power transmission device includes a first switching circuit having a first semiconductor switch for supplying power to the power transmission coil by a switching operation, and a second switching circuit having a second semiconductor switch for supplying power to the power transmission coil. A timer circuit for setting a conduction time of the second semiconductor switch, a switching control circuit for controlling a switching operation, an inductor connected in series to the first semiconductor switch, and a parallel connection to the second semiconductor switch A capacitor connected in series to the power transmission coil, and a resistor connected in series to the power transmission coil, and when the conduction time of the second semiconductor switch exceeds a preset time, A contactless power transmission system having a function of interrupting conduction of the first semiconductor switch Beam can be obtained.

  According to the present invention, the non-contact power described above is characterized in that a MOS field effect transistor (MOSFET) is used for the first semiconductor switch and the second semiconductor switch. A transmission system is obtained.

  According to the present invention, the power transmission device has a function of interrupting conduction of the second semiconductor switch when the conduction time of the second semiconductor switch has passed a preset time. The above non-contact power transmission system is obtained.

  In addition, according to the present invention, an electronic apparatus characterized in that the above-described non-contact power transmission system is incorporated can be obtained.

  The system represents the entire apparatus composed of a plurality of apparatuses.

  The non-contact power transmission system according to the present invention controls the conduction time (current conduction time) between the first semiconductor switch and the second semiconductor switch of the power transmission device, prevents heat generation and damage of the semiconductor element due to overcurrent, It has a protection function against substrate heat generation and burning. Therefore, the protection function of the power transmission device can be strengthened.

  In addition, the power transmission device according to the non-contact power transmission system of the present invention is arranged in a device such as an electronic device so that a portable device that is a power receiving device can be charged, thereby requiring a place to install the power transmission device separately. It will not be.

  That is, according to the present invention, in order to prevent malfunction, it is possible to compactly store a power transmission device equipped with a non-contact power transmission system with an enhanced protection function of the power transmission device, and to provide an electronic device that is less affected by noise. Is possible.

The block diagram of the non-contact electric power transmission system which concerns on this invention. The waveform and time chart which show the 1st protection function operation | movement of the non-contact electric power transmission system which concerns on Embodiment 1 of this invention. The waveform and time chart which show the 2nd protection function operation | movement of the non-contact electric power transmission system which concerns on Embodiment 2 of this invention. Schematic of the electronic device which concerns on Embodiment 3 of this invention. Schematic of the electronic device which concerns on Embodiment 4 of this invention. Schematic of the electronic device which concerns on Embodiment 5 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a block diagram of a non-contact power transmission system according to the present invention. As shown in FIG. 1, the power transmission system of the present invention includes a power transmission device 22 and a power reception device 23 that transmit and receive power without contact.

  The power transmission device 22 is provided with a power transmission coil 7 that generates an alternating magnetic field and an alternating electric field, and a circuit for exciting the coil. The power transmission device 22 includes a first switching circuit 11 having a first semiconductor switch 5 that supplies power from the power transmission power source 1 to the power transmission coil 7 by a switching operation. Similarly, the 2nd switching circuit 12 which has the 2nd semiconductor switch 6 which drives the power transmission coil 7 by switching operation is comprised. Further, a timer circuit 13 for setting the conduction time of the second semiconductor switch 6 and a switching control circuit 14 for controlling the switching operation are configured. Furthermore, the inductor 2 connected in series to the first semiconductor switch 5, the first capacitor 3 connected in parallel to the second semiconductor switch 6, the second capacitor 4 connected in series to the power transmission coil 7, The communication receiving resistor 9 connected in series to the power transmission coil 7 and a signal transmission / reception control circuit 10 that performs a communication signal between the power receiving device 23 are configured.

  The power receiving device 23 includes a power receiving coil 8 that receives an AC magnetic field and an AC electric field from the power transmitting coil 7, a portion that receives power received by the power receiving coil 8, and a portion of a communication circuit that processes signals transmitted and received by the power receiving coil 8. It is made up. The portion that receives the power for charging the secondary battery 21 with the power that has been contactlessly received by the power receiving coil 8 includes a rectifier circuit 18, a DC / DC converter 19, and a battery charge control circuit 20. Further, a communication circuit portion for transmitting information such as charging information of the power receiving device 23 and the power transmitting device 22 includes a load switch 15, a signal reception demodulation circuit 16, and a communication control circuit 17.

(Embodiment 1)
FIG. 2 is a waveform and time chart showing the first protection function operation of the non-contact power transmission system according to Embodiment 1 of the present invention. The first protection function operation according to the first embodiment of the present invention will be described with reference to FIGS. The second switching circuit 12 inputs a “H” or “L” signal to the gate of the second semiconductor switch 6 to control the conduction state, and converts the DC power to the AC power via the second capacitor 4. The power is supplied to the power transmission coil 7 by converting into At this time, the current flowing through the power transmission coil 7 is supplied from the power transmission power source 1 through the first semiconductor switch 5 of the first switching circuit 11. Normally, when power is supplied to the power transmission coil 7, the first semiconductor switch 5 of the first switching circuit 11 is electrically connected to the power transmission power source 1 by controlling the gate of the first semiconductor switch 5 to the “H” signal. Set to state.

  During the period in which the “H” signal is input to the gate of the second semiconductor switch 6 of the second switching circuit 12, that is, the period during which the second semiconductor switch 6 is in a conductive state, the potential of the timer circuit 13 is timed. The potential of the timer circuit 13 remains 0 during the period in which the “L” signal is input to the gate, that is, the period during which the second semiconductor switch 6 is in the non-conductive state.

  When a malfunction of the circuit occurs due to the influence of external EMI and the time of the “H” signal of the gate of the second semiconductor switch 6 becomes long, that is, when the conduction time of the second semiconductor switch 6 becomes long, Although the energization current is controlled by the inductor 2, there is a concern that problems such as semiconductor breakage, circuit breakage, and substrate burnout in the power transmission device 22 may occur.

  The potential of the timer circuit 13 rises as the conduction time of the second semiconductor switch 6 elapses. Therefore, when the potential of the timer circuit 13 reaches the threshold potential set in advance in the timer circuit 13, the second switching circuit 12 sends an "L" signal for shutting off the gate through the switching control circuit 14 to the first switching. Input to the gate of the first semiconductor switch 5 of the circuit 11 to cut off the power supply from the power transmission power source 1. As a result, the power of the power transmission power source 1 cannot be supplied to the second semiconductor switch 6 and the power transmission coil 7, and a protection function can be obtained.

(Embodiment 2)
FIG. 3 is a waveform and time chart showing the second protection function operation of the non-contact power transmission system according to Embodiment 2 of the present invention. A second protection function operation according to the second embodiment of the present invention will be described with reference to FIGS. The first embodiment is different from the first embodiment in a method of cutting off the power supplied to the power transmission coil 7 as a protection function. When the circuit malfunctions due to the influence of external EMI, etc. and the time of the “H” signal of the gate of the second semiconductor switch 6 of the second switching circuit 12 becomes long, that is, the conduction of the second semiconductor switch 6. When the time becomes longer, the potential of the timer circuit 13 increases as the conduction time of the second semiconductor switch 6 elapses. When the potential of the timer circuit 13 reaches the threshold potential set in advance in the timer circuit 13, the second switching circuit 12 inputs an “L” signal for shutting off the gate to the second semiconductor switch 6 to transmit power. By not converting the power supply from the power source 1 from DC power to AC power, the power to the power transmission coil 7 is cut off. As a result, power cannot be supplied to the power transmission coil 7, and a protective function can be obtained in the same manner as the first protective function described in the first embodiment.

  As the embodiment, the first protection function and the second protection function based on the waveforms and the time charts of FIGS. 2 and 3 have been described, but each has a sufficient protection function. Further, by combining the two, it is possible to ensure reliable functional operation and high reliability as a redundant design.

  Although the embodiment applied to the non-contact power transmission system having the communication function has been described above, the present invention can naturally be applied to the non-contact power transmission system having no communication function. In addition, a device having a power transmission coil, for example, a digital camera or a portable music player that includes a coil that generates a magnetic field and has a reader / writer function, a coil that converts a magnetic field into a current, and a rechargeable battery The present invention can be applied to a communication system including a communication terminal or a non-contact IC card.

(Embodiment 3)
Hereinafter, an electronic device in which the non-contact power transmission system described in the first and second embodiments is incorporated will be described. FIG. 4 is a schematic diagram of an electronic device according to Embodiment 3 of the present invention. Here, as an example, a mode in which a power transmission device 60 including a power transmission circuit 61 and a power transmission coil 63 is built in a notebook computer 80 will be described. The notebook computer 80 has normal performance. Inside the notebook computer 80, components on the power transmission side used for the non-contact power transmission system are mounted. The components on the power transmission side include a power transmission circuit 61 that controls power to be transmitted, a metal case 62 that houses the power transmission circuit 61, a power transmission coil 63 that transmits power under the control of the power transmission circuit 61, and a power transmission coil 63. The magnetic body 64 is configured to suppress generated noise. Regarding the arrangement of the power transmission side components, there is a tradeoff with the internal circuit of the personal computer, but it is desirable that the power transmission coil 63 be located at the top of the operation unit of the notebook personal computer 80. If the arrangement of the power transmission coil 63 is determined, a positioning pin or mark may be installed on the notebook computer 80 in order to make the arrangement location easy to understand.

  The power receiving side includes a power receiving circuit 71 that controls received power, a power receiving coil 73 that receives power by controlling the power receiving circuit 71, a magnetic body 74 that suppresses noise generated from the power receiving coil 73, and a secondary that stores the received power. A battery 72 is used. The power receiving coil 73 is desirably on the surface side of the power receiving device 70 facing the power transmitting coil 63 of the power transmitting device 60. By arranging the surface of the power receiving device 70 on which the power receiving coil 73 is mounted facing the power transmitting coil 63 inside the notebook computer 80, it is possible to perform non-contact power transmission and communication with less influence of noise. It becomes an electronic device in which a non-contact power transmission system is incorporated.

(Embodiment 4)
FIG. 5 is a schematic diagram of an electronic apparatus according to Embodiment 4 of the present invention. Here, as in the third embodiment, a description will be given of a mode in which the power transmission device 60 is built in the notebook personal computer 80 and can project outward. As in the third embodiment, a power transmission circuit 61, a metal case 62, a power transmission coil 63, and a magnetic body 64 are mounted inside the notebook computer 80. Further, the power transmission side component is disposed in the drawer portion 81 having a movable structure. The drawer portion 81 can be protruded from the input / output portion 82 for taking in and out the drawer portion 81 of the notebook computer 80 and can be stored in the storage portion 83 for storing the drawer portion 81. The drawer portion 81 may be provided with a positioning pin or a mark so that the place where the power receiving device 70 on which the power receiving side is mounted is easily understood. In addition, the drawer portion 81 is not limited to the box shape as long as the portable device including the power receiving device 70 can be disposed on the upper surface as long as the upper surface portion is provided. The description on the power receiving side is the same as that in the third embodiment.

  By disposing the portable device on which the power receiving device 70 is mounted in a state where the drawer portion 81 is protruded, non-contact power transmission is possible. Since the non-contact power transmission unit protrudes from the notebook computer 80 to the outside, the notebook computer can be easily operated without being disturbed. Further, since the non-contact power transmission unit protrudes from the notebook personal computer 80 main body, the influence of noise on the notebook personal computer main body during operation can be considerably reduced. Further, when non-contact power transmission is not performed, compact storage is possible in the storage unit 83 inside the notebook computer 80, and the power transmission device 60 is not lost.

(Embodiment 5)
FIG. 6 is a schematic diagram of an electronic apparatus according to Embodiment 5 of the present invention. Similarly, a configuration in which the power transmission device 60 is built in the notebook computer 80 and can be pulled out to the outside will be described. As in the third embodiment, a power transmission circuit 61, a metal case 62, a power transmission coil 63, and a magnetic body 64 are mounted inside the notebook computer 80. Further, the power transmission side component is accommodated in the power transmission device 60. The power transmission side component in the power transmission device 60 is connected to a circuit in the notebook computer 80 by a cable 84. The description on the power receiving side is the same as that in the third embodiment.

  By connecting the notebook computer 80 and the power transmission device 60 with the cable 84, the arrangement position of the power transmission device 60 can be provided with a degree of freedom. By disposing a portable device on which the power receiving device 70 is mounted on the power transmitting device 60, non-contact power transmission becomes possible. Moreover, since it is away from the notebook personal computer main body as in the fourth embodiment, the influence of noise on the notebook personal computer 80 can be reduced. When non-contact power transmission is not performed, the drawer portion 81 can be stored in the storage portion 83 inside the notebook computer 80 from the input / output portion 82 together with the cable 84.

  Therefore, by allowing the power transmission device to slide out of the device, charging can be performed without hindering the original purpose of use of the device. In addition, since it slides out of the device and protrudes to the outside, the influence of noise on the device is small, and by connecting the power transmission device to the inside of the device with a cable, it is possible to give flexibility to the arrangement of the power transmission device. Therefore, by carrying out the present invention, it is possible to provide an electronic device equipped with a non-contact power transmission system that can be stored compactly and does not affect the apparatus.

  Here, the apparatus on which the power transmission side component is mounted has been described with a notebook personal computer, but the present invention can be similarly applied to a desktop personal computer. Also, any device that can input power, such as a rack in which another electrical product or an outlet cable is installed, may be used, and it can be built in a dashboard of an automobile.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to these embodiment, Even if there is a design change of the range which does not deviate from the summary of this invention, it is included in this invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used particularly for a charging system for a portable device using a secondary battery by using a non-contact power transmission system and an electronic device in which the non-contact power transmission system is incorporated.

DESCRIPTION OF SYMBOLS 1 Power transmission power source 2 Inductor 3 1st capacitor 4 2nd capacitor 5 1st semiconductor switch 6 2nd semiconductor switch 7 Power transmission coil 8 Power reception coil 9 Communication reception resistance 10 Signal transmission / reception control circuit 11 1st switching circuit 12 Second switching circuit 13 Timer circuit 14 Switching control circuit 15 Load switch 16 Signal reception demodulation circuit 17 Communication control circuit 18 Rectifier circuit 19 DC / DC converter 20 Battery charging control circuit 21 Secondary battery 22 Power transmission device 23 Power reception device 60 Power transmission device 61 power transmission circuit 62 metal case 63 power transmission coil 64 magnetic body 70 power receiving device 71 power receiving circuit 72 secondary battery 73 power receiving coil 74 magnetic body 80 notebook computer 81 drawer part 82 input / output part 83 storage part 84 cable

Claims (4)

A power transmission device having a power transmission coil; and a power reception device provided with a power reception coil that is magnetically coupled to the power transmission coil. A non-contact power transmission system for performing non-contact power transmission from the power transmission device to the power reception device and data communication between the power transmission device and the power reception device through magnetic coupling,
The power transmission device includes a first switching circuit having a first semiconductor switch for supplying power to the power transmission coil by a switching operation, and a second switching circuit having a second semiconductor switch for supplying power to the power transmission coil. A timer circuit for setting a conduction time of the second semiconductor switch, a switching control circuit for controlling a switching operation, an inductor connected in series to the first semiconductor switch, and a parallel connection to the second semiconductor switch A capacitor connected in series to the power transmission coil, and a resistor connected in series to the power transmission coil, and when the conduction time of the second semiconductor switch exceeds a preset time, A contactless power transmission system having a function of interrupting conduction of the first semiconductor switch Beam.   2. The contactless power transmission system according to claim 1, wherein MOS field effect transistors are used for the first semiconductor switch and the second semiconductor switch.   The said power transmission apparatus has a function which interrupts | blocks conduction | electrical_connection of a said 2nd semiconductor switch, when the conduction | electrical_connection time of a said 2nd semiconductor switch passes the preset time. Non-contact power transmission system.   An electronic apparatus in which the non-contact power transmission system according to claim 1 is incorporated.

Images