JP2008211898A - Input protection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an input protection device capable of detecting various abnormal inputs by constantly monitoring inputs of an electronic apparatus, promptly taking a preventive action, and eliminating need for drive power. <P>SOLUTION: This input protection device includes a voltage detection unit which is located in a flux generated by a permanent magnet and includes a movable coil slanted by torque generated by running current, a resistor which is connected with the voltage detection unit in series and floats current proportional to input voltage in the movable coil, an insulation body continuously formed, a plate-shaped member constructed from a resistance body and a conductor, and a variable resistance part which is provided with a movable contactor which moves synchronously with slant motion of the movable coil in contact with the plate-shaped member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an input protection device that can protect an electronic device from various abnormal inputs such as input monitoring of an electronic device and inrush current and burst noise (such as lightning surge and static electricity).

  In electric motors, winding devices such as fans and transformers, electronic devices with large-capacity capacitors used for voltage smoothing and decoupling, or incandescent lamps, it is known that a larger current than the steady state flows when the power is turned on. ing. Such a large current is called an inrush current.

  In circuits that do not take into account inrush currents, welding of power switch contacts, fusing of fuses and breakers in power supply lines, breakage of rectifier circuits, power supply voltages and output voltages used in electronic circuits become unstable Various problems occur. In addition, an electronic device sharing the power supply voltage with such a circuit is also adversely affected.

  These problems can be avoided by designing an electronic circuit in consideration of the magnitude of the inrush current in advance and using a circuit element that can withstand the inrush current, but using a circuit element that is larger and more expensive than necessary. turn into. Also, if a fuse or breaker with a larger rated current is selected in consideration of the inrush current, it may not function even if an abnormality occurs during steady operation.

  Therefore, as a fundamental measure against the inrush current, a method of reducing the inrush current itself by increasing the rise time of the power supply voltage can be considered. However, in order to increase the rise time of the power supply voltage, for example, when a resistor is inserted in series with the power supply input of the electronic circuit to be protected, there is a problem that power is wasted by the resistor even during steady operation. . In order to avoid wasteful power consumption during the steady operation, there is a method in which an element called a power thermistor having a negative temperature coefficient is inserted in series with the power supply input of the electronic circuit instead of the resistor. The power thermistor has a high resistance value when it is cold immediately after the power is turned on, and the resistance value becomes small when it is warmed by the flow of current. Therefore, it is possible to avoid wasteful power consumption during steady operation. However, if the power thermistor shuts off the power supply once after a steady operation and then turns on the power supply immediately after that, the temperature does not drop sufficiently (because the resistance value is small), and the inrush current cannot be reduced. There are drawbacks.

  As another method for reducing the inrush current, for example, in Patent Document 1, a resistor is inserted in series with the ground line in the power circuit, and the resistor is used as it is when the power is turned on. Describes a configuration in which the resistors are short-circuited using a relay.

Although it is not a countermeasure against inrush current, as a method for protecting an electronic device from an overvoltage input, for example, in Patent Document 2, when a relay is inserted in a power supply line and an overvoltage of the power supply is detected, the electronic device is detected by the relay A configuration for cutting off the power supply is described.
JP 2005-295649 A Japanese Utility Model Publication No. 6-18166

  As described above, in the input protection devices described in Patent Documents 1 and 2, inrush current and overvoltage input are suppressed using a relay. However, in general, a relay has a complicated structure, so that an operation (response) time is slow, and a large driving power is required to operate a contact point by an exciting force generated by passing a current through a coil. Therefore, there is a problem that power consumption increases.

  In addition to inrush current, factors that adversely affect electronic devices include various abnormal inputs such as burst noise (for example, lightning surge and static electricity) and voltage fluctuations. It is necessary to provide the means.

  In the future, for large-scale circuits with higher speed and higher density, it will become increasingly important to ensure safety and reliability by installing means that can always protect against various abnormal inputs such as inrush current in the power supply circuit etc. It becomes.

  In addition, various electronic devices that may be stopped or damaged due to inrush currents or various abnormal inputs can be protected from inrush currents and various abnormal inputs with new elements that can be realized at low cost and with a simple configuration. Development is desired.

  Of course, for the purpose of reducing power consumption and improving power efficiency, it is indispensable to combine the characteristics of low loss during steady operation, which is an advantage of the relay used in the prior art.

  The present invention has been made to solve all of the problems of the conventional techniques as described above, and various abnormal inputs can be detected by constantly monitoring the input of the electronic device, and immediate preventive measures are taken. An object of the present invention is to provide an input protection device that does not require drive power.

In order to achieve the above object, an input protection device of the present invention is placed in a magnetic field generated by a permanent magnet, and includes a voltage detection unit including a movable coil that is inclined by a torque generated when a current flows;
A resistor connected in series with the voltage detector for flowing a current proportional to an input voltage through the movable coil;
A variable resistance portion having a plate-like member formed of a continuously formed insulator, a resistor, and a conductor, and a movable contact that moves in contact with the plate-like member in synchronization with an inclination operation of the movable coil; ,
Have

  In the input protection device configured as described above, the movable coil of the voltage detection unit tilts according to the value of the input voltage, and the movable contact of the variable resistance unit contacts the plate member in synchronization with the tilting operation of the movable coil. For example, if the plate-like member is formed so that the movable contact contacts the resistor when the power is turned on or when an abnormal voltage is input, the inrush current of the electronic device connected in series with the input protection device is reduced. And abnormal voltage can be suppressed.

  Also, if a plate-like member is formed so that the movable contact contacts the insulator when there is an abnormal input that can damage the electronic device such as burst noise, the abnormal input can be prevented from flowing into the electronic device. . Furthermore, if the plate-like member is formed so that the movable contactor contacts the conductor during the steady operation, the loss in power transmission during the steady operation can be suppressed in the same way as the conventional technique using a relay. In addition, the present invention has a structure in which input monitoring and input protection are always performed automatically and automatically by the input current and the magnetic force of the permanent magnet, and can be realized with a simple structure that does not require any driving power of the element itself.

  According to the present invention, it is possible to obtain an input protection device that does not require driving power and that can detect various abnormal inputs by constantly monitoring the input of the electronic device and can immediately take preventive measures.

  Next, the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing one configuration example of the input protection device of the present invention. FIG. 2 is a diagram showing the operation principle of the input protection device shown in FIG. 1, in which FIG. 2 (a) is a schematic diagram showing the movement of the movable coil and the movable contact, and FIG. 2 (b) is shown in FIG. It is an equivalent circuit of an input protection device.

  As shown in FIG. 1, the input protection device of the present invention has a configuration including a voltage detection unit 1 and a variable resistance unit 2.

  The voltage detector 1 has the same structure as a known DC ammeter, and a soft iron core 13 is disposed in a magnetic field generated by the N pole permanent magnet 11 and the S pole permanent magnet 12, and is movable around the soft iron core 13. The coil 14 is attached.

  The variable resistance unit 2 includes a plate-like member 21 composed of three types of elements, an insulator, a resistor, and a conductor, and a movable contact 22 that contacts the plate-like member 21. ing. A hinge part 23 is attached to the movable contact 22, and the movable contact 22 is mechanically connected to the movable coil 14 via the hinge part 23. The movable contact 22 and the hinge part 23 are formed of a conductor such as metal.

  The movable contact 22 of the variable resistor 2 is connected to the input terminal (input) 31 of the input protection device, and the conductor portion of the plate-like member 21 is connected to the output terminal (output) 32.

  The voltage detection unit 1 is connected in series with a resistor (Ro) 3, and the voltage detection unit 1 and the resistor 3 connected in series are connected in parallel between the input terminal 31 and the ground potential (GND). The resistor (Ro) 3 is provided to allow a current proportional to the input voltage applied between the input terminal (input) and the ground potential (GND) to flow through the movable coil 14 of the voltage detection unit 1.

  In such a configuration, as shown in FIG. 2A, a current proportional to the input voltage applied between the input terminal 31 and the ground potential is applied to the movable coil 14 of the voltage detection unit 1 via the resistor 3. Flowing. At this time, torque is generated in the movable coil 14 by the magnetic field generated by the N-pole permanent magnet 11 and the S-pole permanent magnet 12 and the magnetic field generated by the current flowing through the movable coil 14, and the movable coil 14 tilts. . Since this torque is proportional to the input voltage, the amount of inclination of the movable coil 14 is proportional to the input voltage. The tilting operation of the movable coil 14 is transmitted to the movable contact 22 of the variable resistance unit 2 via the hinge 23 to move the movable contact 22.

  As shown in FIG. 1, an insulator is disposed on the plate-like member 21 of the variable resistance portion 2 at the initial position of the movable contact 22 corresponding to, for example, the inclination amount of the movable coil 14 being zero. A body, a conductor, a resistor, and an insulator are successively formed. The arrangement order and length of these elements are arbitrary, and may be appropriately set according to the application of the input protection device of the present invention, the specifications of the electronic device to be protected, and the like.

  The movable contact 22 moves in contact with the plate-like member 21 in synchronization with the tilting operation of the movable coil 14 that is proportional to the input voltage. Therefore, between the input terminal 31 and the output terminal 32, the movable contact 22 and the insulator, resistor, or conductor of the plate member 21 that is in contact with the movable contact 22 are inserted according to the input voltage. Become.

  That is, as shown in FIG. 2B, the input protection device of the present invention has a DC voltmeter connected in parallel between the input terminal and the ground potential, and the input voltage applied between the input terminal and the ground potential is converted to a DC voltmeter. This is equivalent to a circuit that controls the resistance value of the variable resistor inserted in series between the input and output terminals according to the measured value.

  As described above, the input protection device according to the present invention is configured to control the resistance value between the input and output terminals in accordance with the input voltage. Therefore, the output terminal 32 is connected to the electronic device and the DC voltage is supplied from the input terminal 31. For example, it can be operated as a circuit for controlling the DC voltage supplied to the electronic device to be constant.

  Next, a typical operation of the input protection device of the present invention will be described with reference to FIG.

  FIG. 3 is a schematic diagram showing a state of protection operation by the input protection device shown in FIG.

  As shown in FIG. 3, when the power is turned on, the movable contact 22 moves on the plate-like member 21 from the initial position, and stops at a position where it comes into contact with the conductor when the steady operating voltage is reached. When the power supply voltage rises, the movable contact 22 is in contact with the resistor until the input voltage reaches the vicinity of the steady operating voltage. Therefore, the resistor inserted between the input terminal 31 and the output terminal 32 causes the output terminal to The inrush current to the electronic device connected to is reduced. In addition, since the movable contact 22 is in contact with the conductor of the plate-like member 21 after the input voltage reaches the steady operating voltage, a conventional technique using a relay or the like for the electronic device connected to the output terminal 32. Power supply voltage is supplied with little power loss.

  Further, when the input voltage is suddenly reduced or a power failure occurs and the input voltage returns immediately (instantaneous drop, instantaneous interruption), the movable contact 22 moves from the conductor portion of the plate-like member 21 and comes into contact with the resistor. Inrush current to the electronic device connected to the output terminal 32 is reduced by the resistor inserted between the output terminal 32 and the output terminal 32.

  Further, when the input voltage becomes an abnormal voltage higher than the steady operation voltage, the movable contact 22 moves from the conductor portion of the plate-like member 21 and comes into contact with the resistor, and therefore, between the input terminal 31 and the output terminal 32. The abnormal voltage applied to the electronic device connected to the output terminal 32 is suppressed by the voltage drop of the inserted resistor.

Further, when burst noise such as lightning surge or static electricity is superimposed on the input voltage, the movable contact 22 moves greatly from the conductor portion of the plate-like member 21 and comes into contact with the insulator. Thus, abnormal input such as burst noise to the electronic device connected to the output terminal 32 is prevented.
(Example)
Next, an embodiment of the input protection device of the present invention will be described with reference to the drawings.

  FIG. 4 is a diagram showing an example of use of the input protection device of the present invention. FIG. 4 (a) is a block diagram showing an application example to a power supply circuit, and FIG. 4 (b) shows an electronic device operating with a DC voltage. It is a block diagram which shows an application example.

  The input protection device of the present invention shown in FIG. 1 can be adjusted by adjusting the values and lengths of the resistors, conductors, and insulators of the plate-like member 21 or the amount of inclination of the movable coil 14 according to the application. It can be easily applied to various specifications.

  FIG. 4A shows an example in which the input protection device of the present invention is used in a power supply circuit that generates a DC voltage (DC) from an AC voltage (AC). The power circuit shown in FIG. 4A includes an AC outlet 41, an EMI (Electro Magnetic Interference) filter 42, a diode rectifier circuit 43, a power factor correction circuit (PFC) 44, a transformer 45, and a smoothing circuit 46. I have. FIG. 4B shows an example in which the input protection device of the present invention is used in an electronic device that operates with a DC voltage. The electronic device shown in FIG. 4B includes a fan (FAN) 51 and an electronic circuit 52.

  Since each circuit of the power supply circuit shown in FIG. 4A and the fan 51 and the electronic circuit 52 shown in FIG. 4B may use a known configuration or a general-purpose product, detailed description thereof will be omitted.

  In the power supply circuit shown in FIG. 4A, the input protection device 10 of the present invention is inserted between the diode rectifier circuit 43 and the power factor correction circuit 44, and the electronic device shown in FIG. The input protection device 10 of the present invention is inserted into the. In the power supply circuit shown in FIG. 4A, the voltage detector 1 measures the average value of the full-wave rectified pulsating flow and does not follow the AC component, so the wear of the movable contact 22 is ignored. it can.

  As described above, for example, when the fan 51 is started, or in a configuration in which an electronic device is started after charging with a large-capacity capacitor after the power is turned on, an inrush current larger than the rated current may flow. In a conventional power supply circuit, when a current larger than the rated current flows, a protection circuit provided therein is activated to stop supplying power, and the entire system operation may be stopped. Even in such a configuration, by inserting the input protection device of the present invention, it is possible to avoid a power supply stop due to a temporary increase in current. Therefore, by providing the input protection device 10 of the present invention, an inrush current or burst can be applied to a power supply circuit as shown in FIG. 4A or an electronic device operating with a DC voltage as shown in FIG. It becomes possible to protect electronic devices from abnormal inputs such as noise. In particular, in a system in which a plurality of electronic devices are operated with one power supply circuit, a failure that occurs in one device may affect other electronic devices. Therefore, by using the input protection device of the present invention. Such an influence on the entire system can also be reduced.

  Since the input protection device of the present invention is configured to operate the movable coil 14 and the movable contact 22 in synchronization as described above, the voltage detection unit 1 and the variable resistor as shown in FIG. It is also possible to form a one-chip component by housing the part 2 in one package and providing three terminals, an input terminal (input), an output terminal (output), and a ground terminal (GND). At this time, if the resistance value of the resistor 3 (Ro shown in FIG. 5A) 3 connected in series with the voltage detector 1 is set to 0Ω, the voltage detector 1 can be operated as an ammeter. .

  The input protection device shown in FIGS. 5 (a) and 5 (b) can be mounted on an electronic device by downsizing and can be installed after the design and development of the electronic device. It can also be used for improvement.

  Further, as shown in FIG. 6B, a detection terminal (sense) is added to the input protection device shown in FIG. 5B, and the voltage detection unit 1 is connected between the detection terminal and the ground terminal (GND). By inserting and forming an independent configuration, the resistance value of the variable resistance unit 2 inserted between the input terminal (input) and the output terminal (output) is controlled by the voltage value or current value detected by the voltage detection unit 1. A configuration is also possible (see FIG. 6A). In this case, if the input terminal (input) and the detection terminal (sense) are disconnected by inserting an insulator between the input terminal (input) and the detection terminal (sense) as shown in FIG. Good. Such a configuration can be used in various applications by adjusting the values and lengths of the conductors, resistors, and insulators of the variable resistor section 2. As shown in FIG. 6 (c), the input protection device shown in FIGS. 6 (a) and 6 (b) has a DC ammeter connected in series between the detection terminal and the ground potential, and between the detection terminal and the ground potential. This is equivalent to a circuit that measures the input current flowing through the input / output terminal using a DC ammeter and controls the resistance value of the variable resistor inserted in series between the input and output terminals according to the measured value.

  For example, the input protection device shown in FIGS. 6A to 6C can be used as a variable resistor that controls the resistance value between the input and output terminals by the voltage applied to the detection terminal (sense). As described above, the input protection device shown in FIG. 6 can be used not only for the purpose of protecting the electronic circuit from abnormal input but also as a control element such as a variable resistor.

  As described above, according to the input protection device of the present invention, it is possible to protect electronic equipment from abnormal inputs such as inrush current and burst noise. It is also possible to stabilize the input voltage by measuring the input voltage using the movable coil 14 and controlling the resistance value according to the input voltage by the variable resistance unit 2. Further, if the movable contact 2 is adjusted so as to be positioned on the conductor during the steady operation, the power loss during the steady operation can be suppressed in the same way as the conventional technique using a relay or the like.

  Moreover, since the input protection device of the present invention does not require driving power unlike a relay, power consumption does not increase.

  Further, the input protection device of the present invention can be made into one chip because of its simple structure, and various values can be obtained by adjusting the values and lengths of the conductors, resistors, and insulators of the variable resistor section 2. Can be used for various purposes.

  Furthermore, since the input protection device of the present invention can be used not only for input protection of a power supply circuit that generates a DC voltage from an AC voltage but also for electronic devices that operate with a DC voltage, it can be used in a wide range of fields. .

It is a schematic diagram which shows one structural example of the input protection apparatus of this invention. It is a figure which shows the principle of operation of the input protection apparatus shown in FIG. 1, The figure (a) is a schematic diagram which shows a motion of a movable coil and a movable contact, The figure (b) is the input protection apparatus shown in FIG. Is an equivalent circuit. It is a schematic diagram which shows the mode of the protection operation | movement by the input protection apparatus shown in FIG. It is a figure which shows the utilization example of the input protection apparatus of this invention, The figure (a) is a block diagram which shows the example of application to a power supply circuit, The figure (b) is the example of application to the electronic device which operate | moves with a DC voltage. FIG. It is a figure which shows an example of the one-chip components which implement | achieve the input protection apparatus of this invention, The figure (a) is a circuit diagram, The figure (b) is a perspective view which shows the example of a structure. It is a figure which shows the other example of the one-chip component which implement | achieves the input protection apparatus of this invention, The figure (a) is a circuit diagram, The figure (b) is a perspective view which shows the structural example, The figure (c) is the figure. It is an equivalent circuit diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage detection part 2 Variable resistance part 3 Resistor 10 Input protection apparatus 11 N pole permanent magnet 12 S pole permanent magnet 13 Soft iron core 14 Movable coil 21 Plate-like member 22 Movable contactor 23 Hinge part 41 AC outlet 42 EMI filter 43 Diode Rectifier circuit 44 Power factor correction circuit 45 Transformer 46 Smoothing circuit 51 Fan 52 Electronic circuit

Claims (5)

A voltage detection unit including a moving coil that is placed in a magnetic field generated by a permanent magnet and tilted by a torque generated when a current flows;
A resistor connected in series with the voltage detector for flowing a current proportional to an input voltage through the movable coil;
A variable resistance portion including a continuously formed insulator, a resistor and a plate-like member made of a conductor, and a movable contact that moves while contacting the plate-like member in synchronization with the tilting operation of the movable coil; ,
An input protection device. The plate-like member is
The input protection device according to claim 1, wherein an insulator is disposed at an initial position of the movable contact, and the insulator, the resistor, the conductor, the resistor, and the insulator are successively formed.   A power supply circuit comprising the input protection device according to claim 1 and generating a DC voltage from an AC voltage.   An electronic device comprising the power supply circuit according to claim 3. An input protection device according to claim 1 or 2,
An electronic circuit operating with a DC voltage;
Electronic equipment having

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