JP2006165734A - Excess input protecting apparatus and excess input protecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excess input protecting apparatus and an excess input protecting method for protecting a high-frequency apparatus, when receiving a high-frequency signal with large power in excess of a permitted value, without the need for provision of an exclusive power supply. <P>SOLUTION: A high-frequency switch 101 applies a high frequency input signal S1 to a directional coupler 102, when the high-frequency switch 101 is closed, and interrupts the high-frequency input signal S1, when the high frequency switch 101 is opened. The directional coupler 102 passes the high-frequency input signal S1 at a low loss and supplies the high-frequency input signal S1 to a detection circuit 103 as a traveling wave monitor signal S3 at a ratio in compliance with the degree of coupling. The detection circuit 103 detects the traveling wave monitor signal S3, supplied from the directional coupler 102, to generate a switch switching signal S4, thereby controlling the high-frequency switch 101. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an over-input protection device and an over-input protection method for protecting a high-frequency device when a high-power high-frequency signal exceeding an allowable value is input.

  2. Description of the Related Art Conventionally, in a high-frequency device to which a high-frequency signal is input, as an apparatus having an over-input protection function for preventing element damage due to an excessive level of input, an excessively large field effect transistor (hereinafter referred to as FET) is used. There has been a base station receiving amplifier used in a mobile communication system that automatically controls a received signal (see, for example, Patent Document 1).

  FIG. 8 is a diagram showing a schematic configuration of a conventional base station receiving amplifier. As shown in FIG. 8, when an excessive level received signal is input to the input terminal 801 and the detection voltage 808 exceeds the reference voltage 810, the switching unit 809 blocks the reference voltage 810 and detects the detection voltage 808 as the reference signal 811. Is supplied to the comparison control unit 812.

  Accordingly, since the balanced state is obtained when the reference voltage 810 is used as the reference signal 811, the voltage difference between the reference signal 811 and the drain voltage 814 is almost zero, but the balance is lost due to an excessive input, and the comparison control is performed. The unit 812 amplifies the difference between the two, sets the gate voltage 815 to a large negative voltage, and stops the high frequency amplification function of the FET 805.

On the other hand, in the delay unit 803, a delay time equal to or longer than the time until the detection unit 802 detects an excessive input, the switching unit 809 performs a switching process, and the comparison amplification unit 812 controls the gate voltage 815 to a large negative voltage. It is set, and an input signal of an excessive level is prevented from being input to the FET 805 until the gate voltage 815 is controlled.
Japanese Patent No. 3017160

  However, the conventional high-frequency amplifier circuit has a situation that a dedicated power supply means is required to realize the over-input protection function.

  The present invention has been made in view of the above-described conventional circumstances, and does not require a dedicated power supply, and is an over-input protection device that protects a high-frequency device when a high-frequency high-frequency signal exceeding an allowable value is input. And an over-input protection method.

  The over-input protection device of the present invention detects the high-frequency input signal by switching means for passing or outputting the input high-frequency signal or shutting it off, and converts the detection signal into driving power for the switch. Detecting means for generating a control signal for the switching means, and for switching the switching means to a cut-off state when the power of the high-frequency input signal exceeds a predetermined value.

  With this configuration, the power of the detection signal of the input high-frequency input signal is converted to the power of the control signal that controls the switching means for switching between outputting and shutting off the high-frequency signal, thus eliminating the need for power supply. it can.

  Further, in the over-input protection device of the present invention, the switching unit has the high frequency input signal as an input, and has either a short circuit state in which the high frequency input signal is output or an open state in which the high frequency input signal is blocked. A switch provided in parallel with the switch, the switch changes from a short-circuited state to an open state when a current flows through the coil, and the detection means includes the detection unit. High impedance when the signal is input to the gate and the drain-source impedance is lower than a predetermined value of the power of the high-frequency input signal to be detected, and low impedance when the power of the high-frequency input signal to be detected is greater than or equal to a predetermined value The coil has one of the coils at the gate and the other at the drain of the field effect transistor. It is connected to the emissions.

  With this configuration, the switching means can be shut off using a signal detected when the high-frequency input signal is equal to or higher than a predetermined value, so that an over-input protection device that does not require power supply can be provided.

  The overinput protector of the present invention includes the above-described overinput protection device, input connection means for receiving a high-frequency input signal supplied from the outside, and connecting the input to the input of the overinput protection device, and the overinput protection device Output connection means connected to an output and outputting a signal from the over-input protection device to the outside.

  With this configuration, it can be used as an over-input protector that does not require power supply simply by connecting to the input side of the high-frequency device.

  An electronic device according to the present invention includes an electronic device operating unit that functions according to an input high-frequency signal, and the over-input protection device connected to an input side of the electronic device operating unit.

  This configuration eliminates the need for a dedicated power supply in order to realize the over-input protection function, so that power consumption can be reduced.

  The over-input protection method of the present invention includes a step of detecting a high-frequency input signal, and converting the detected signal into drive power for the switch to generate a control signal for the switching means, and the power of the high-frequency input signal is predetermined. When the value exceeds the value, the input high-frequency signal is passed through and output, or the switching means for blocking is set in a blocking state.

  By this method, the power of the detection signal of the input high-frequency input signal is converted into the power of the control signal for controlling the switching means for switching between outputting and shutting off the high-frequency signal, thus eliminating the need for power supply. it can.

  According to the present invention, it is possible to provide an over-input protection device and an over-input protection method for protecting a high-frequency device when a high-power high-frequency signal exceeding a permissible value that does not require a dedicated power supply is input.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an over-input protection device according to the first embodiment of the present invention. As illustrated in FIG. 1, the over-input protection device 100 according to the first embodiment includes a high-frequency switch 101, a directional coupler 102, and a detection circuit 103.

  The high frequency switch 101 has either one of an on state and an off state, and when it is in the on state, the input high frequency input signal S1 is allowed to pass, and when it is in the off state, the high frequency input signal S1 is cut off.

  The directional coupler 102 passes the high-frequency input signal S1 that has been passed through and output when the high-frequency switch 101 is in the on state with low loss and outputs it as a high-frequency output signal S2, and the traveling wave has a predetermined degree of coupling. The traveling wave monitor signal S3 is output at a ratio according to the above.

  The detection circuit 103 detects a high-frequency signal and outputs a signal corresponding to the amplitude of the high-frequency signal as a switch control signal S4 for controlling the state of the high-frequency switch 101.

  FIG. 2 is a diagram illustrating an example of the high-frequency switch according to the first embodiment. As shown in FIG. 2, the high-frequency switch 101 includes a switch 201 and a drive coil 202. When the switch 201 is on (short-circuited), a current of a predetermined value or more flows through the drive coil 202. (Open state). It should be noted that once opened, the opened state is maintained even when the current flowing through the drive coil 202 becomes a predetermined value or less.

  The drive coil 202 is supplied with a power supply S41 at one end and a switch control signal S4 as a switching signal S42 at the other end.

  FIG. 3 is a diagram illustrating an example of the directional coupler according to the first embodiment. As shown in FIG. 3, the directional coupler 102 includes a coupling portion 301 and a resistor 302 having one end installed and the other end connected to the coupling portion.

  The combining unit 301 passes the input high-frequency input signal S1 with low loss and outputs it as a high-frequency output signal S2, and outputs a traveling wave as a traveling wave monitor signal S3 at a ratio according to the degree of coupling. The resistor 302 terminates the reflected wave.

  FIG. 4 is a diagram illustrating an example of the detection circuit according to the first embodiment. As shown in FIG. 4, the detection circuit 103 includes a detection diode 401, a capacitor 402 and a resistor 403 that are connected to the output side of the detection diode 401 with one end grounded, a field effect transistor (hereinafter referred to as FET) 404, and Have

  The detection unit having the detection diode 401, the capacitor 402, and the resistor 403 detects the high-frequency input signal S1 based on the traveling wave monitor signal S3 input to the detection diode 401. The FET 404 functions as a switching element in which the signal detected by the detection unit is input as a gate voltage, and when the gate voltage exceeds a certain value, the source and drain are shifted from high impedance to low impedance.

  FIG. 5 is a timing diagram for explaining the operation of the over-input protection device of the first embodiment. FIG. 5A is a high-frequency input signal S1, FIG. 5B is a traveling wave monitor signal S3, and FIG. 5 (C) shows the power supply S41 of the switch control signal S4, FIG. 5 (D) shows the voltage and current of the switching signal S42 of the switch control signal S4, and FIG. 5 (E) shows the state of the high-frequency switch 101.

  In this example, as an initial state, the high frequency switch 101 is in an on state, and an input and an output are connected. Then, as shown in FIG. 5A, a case where the high-frequency input signal S1 simply increases from 0 [W] at time T1 and reaches W1 [W] at time T3 will be described. Further, the FET 404 of the detection circuit 103 assumes that the impedance between the drain and the source is switched from the high impedance to the low impedance when the power supply S41 as the gate voltage becomes V1 [V] or more. Furthermore, when a current of I1 [A] or more flows through the drive coil 202 of the high frequency switch 101, the switch 201 is switched to an open state and turned off, and the input high frequency input signal S1 is cut off.

  As shown in FIG. 5B, the traveling wave monitor signal S3 increases as the high-frequency input signal S1 increases, and becomes k × W1 [W] at time T3. Here, k is the degree of coupling of the directional coupler 102.

  As shown in FIG. 5C, the voltage of the power supply S41 of the switch control signal S4 starts to increase from T2 after a predetermined time has elapsed from time T1, and reaches the voltage V1 [V] at time T3.

  When the power supply S41 input to the gate of the FET 404 reaches the voltage V1 [V], the drain-source impedance of the FET 404 is switched to low impedance, and the current of the switching signal S42 as shown in FIG. Starts to flow and reaches current I1 [A] at time T4 after a predetermined time has elapsed from time T3.

  At time T4, since the current of the switching signal S42 becomes I [A], the current flowing through the drive circuit 202 becomes I [A], so that the switch 201 is switched from the short circuit state to the open state. That is, the high frequency switch 101 is switched from the on state to the off state, and the input high frequency input signal S1 is cut off. In this way, since the high frequency input signal S1 is cut off when the electric power exceeds the allowable value and the signal is not output to the subsequent stage, the high frequency device connected to the subsequent stage can be protected from excessive input.

  According to the first embodiment of the present invention as described above, the power of the detection signal of the input high-frequency input signal is converted to the power of the control signal that controls the high-frequency switch that switches between outputting and shutting off the high-frequency signal. Therefore, it is possible to provide a high frequency protection circuit that does not require a dedicated power supply.

(Second Embodiment)
FIG. 6 is a block diagram showing a schematic configuration of the overinput protector according to the second embodiment of the present invention. As shown in FIG. 6, the overinput protector 600 according to this embodiment includes connectors 601 and 603 that are connected to an external device, and an overinput protector 602. The over-input protection unit 602 includes the over-input protection device 100 according to the first embodiment shown in FIG.

  The connector 601 receives an input from an external device that supplies a high-frequency signal, and connects to the input of the over-input protection unit 602. The connector 603 is connected to the output of the over-input protection unit 602 and connects to the high-frequency output signal receiving unit of the external device.

  According to the second embodiment of the present invention, by converting the power of the input high-frequency signal into the high-frequency switch driving power, the high-frequency device is protected when a high-power high-frequency signal exceeding the allowable value is applied. Therefore, it is possible to provide an overinput protector that does not require a dedicated power supply.

(Third embodiment)
FIG. 7 is a block diagram showing a schematic configuration of an electronic apparatus according to the third embodiment of the present invention. As shown in FIG. 7, the electronic device of this embodiment includes an over-input protection unit 701 and an electronic device main function unit 702. The overinput protection unit 602 includes the overinput protection device 100 according to the first embodiment shown in FIG.

  The electronic device main function unit 702 is for realizing the functions of the entire electronic device, and performs a desired operation using a high-frequency signal as an input. When the electronic device main function unit 702 has a plurality of input terminals, the power of the input high-frequency signal exceeds the allowable value by connecting the over-input protection unit 701 to a terminal to be protected from over-input. In addition, a high frequency signal is not input to the input terminal of the electronic device main function unit 702, and element destruction due to excessive input can be prevented.

  According to the third embodiment of the present invention, by converting the power of the input high-frequency signal into the high-frequency switch driving power, the high-frequency device is protected when a high-power high-frequency signal exceeding an allowable value is applied. Therefore, an electronic device with reduced power consumption can be provided.

  INDUSTRIAL APPLICABILITY The overinput protection device and the overinput protection method of the present invention have an effect that does not require a dedicated power supply, and are useful for electronic devices that use high-frequency signals.

1 is a block diagram showing a schematic configuration of an overinput protection device according to a first embodiment of the present invention. The figure which shows an example of the high frequency switch of 1st Embodiment The figure which shows an example of the directional coupler of 1st Embodiment The figure which shows an example of the detection circuit of 1st Embodiment Timing chart for explaining the operation of the over-input protection device of the first embodiment The block diagram which shows schematic structure of the overinput protector which concerns on the 2nd Embodiment of this invention. The block diagram which shows schematic structure of the electronic device which concerns on the 3rd Embodiment of this invention. The figure which shows schematic structure of the conventional amplifier for base station reception

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Over-input protective device 101 High frequency switch 102 Directional coupler 103 Detection circuit 201 Switch 202 Drive coil 301 Coupling part 302,403 Resistance 401 Detection diode 402 Capacitor 404 FET
600 Over-input protector 601 and 603 Connector 602 and 701 Over-input protection unit 700 Electronic device 702 Electronic device main function unit

Claims (5)

Switching means for passing the input high-frequency signal and outputting or shutting it off;
The high-frequency input signal is detected, the detection signal is converted into drive power for the switch to generate a control signal for the switching means, and when the power of the high-frequency input signal exceeds a predetermined value, the switching means is A detection means for switching off,
An over-input protection device comprising: The over-input protection device according to claim 1,
The switching means has the high-frequency input signal as an input, a switch having either a short-circuit state for outputting the high-frequency input signal or an open state for blocking the high-frequency input signal, and in parallel with the switch A coil provided, and the switch changes from a short-circuit state to an open state when a current flows through the coil,
The detection means has a high impedance when the detection signal is input to the gate and the drain-source impedance is lower than a predetermined value of the power of the high-frequency input signal to be detected, and the power of the high-frequency input signal to be detected is predetermined. Has a field effect transistor that has a low impedance when above the value,
One of the coils is connected to the gate, and the other is connected to the drain of the field effect transistor. The overinput protection device according to claim 1 or 2,
Input connection means for receiving a high frequency input signal supplied from the outside and connecting to an input of the over-input protection device;
Output connection means connected to the output of the over-input protection device and outputting a signal from the over-input protection device to the outside;
Over input protector with. Electronic device operating means that functions according to the input high-frequency signal;
The over-input protection device according to claim 1, connected to the input side of the electronic device operating means,
Electronic equipment comprising. Detecting a high frequency input signal;
The detected signal is converted into drive power for the switch to generate a control signal for the switching means, and when the power of the high-frequency input signal exceeds a predetermined value, the input high-frequency signal is passed and output. Or setting the switching means to be blocked to a blocking state;
An over-input protection method.

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