JP2011250077A - Amplifying device and wireless communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amplifying device capable of reducing the dispersion of a drain current caused by the difference of device characteristics.SOLUTION: An amplifying device 3B includes: an amplifying element 10 which outputs an output signal S2 from an output terminal 14 by amplifying an input signal S1 input into an input terminal 12; a temperature detection element 41 arranged adjacent to the amplifying element 10 and output value of which varies according to the temperature of the amplifying element 10; and an operational amplifier 11 which generates an output voltage V6 for bringing the current value of the drain current Id passing through the amplifying element 10 to a default value, and applies a bias voltage V7 based on the output voltage V6 on a gate electrode G of the amplifying element 10.

Description

  The present invention relates to an amplifying device and a wireless communication device including the same.

  Patent Document 1 listed below discloses a high-frequency amplifier including an FET (Field-Effect-Transistor). The FET has a gate electrode connected to the signal input terminal, a drain electrode connected to the power supply terminal, and a source electrode connected to the ground terminal. The drain current of the FET is controlled by the gate voltage applied to the gate electrode.

Japanese Patent No. 3177559

  However, due to the manufacturing process, the gate voltage-drain current characteristics of the FET vary from product to product. In an amplifying apparatus using an FET in which an excessive drain current flows, the amplification efficiency of the amplifying apparatus decreases due to excessive power consumption caused by the excessive drain current. On the other hand, in an amplifying device using an FET through which an excessively small drain current flows, the amplifying gain of the amplifying device is reduced due to the lack of the drain current. Further, in an amplifying apparatus using an FET in which an excessive drain current flows, an unexpected abnormal signal is generated due to oscillation caused by a decrease in isolation. Due to this abnormal signal, the output signal of the FET may be distorted, or the components of the amplifier circuit and its peripheral circuits may be damaged.

  In order to set the value of the drain current that flows when a certain gate voltage is applied to each other, individual adjustment for each product is required, which increases the manufacturing period and the manufacturing cost.

  The present invention has been made in view of such circumstances, and an object thereof is to obtain an amplifying device capable of reducing variations in drain current due to a difference in element characteristics, and a wireless communication device including the same. To do.

  An amplifying device according to a first aspect of the present invention includes an amplifying element that outputs an output signal from an output terminal by amplifying an input signal input to an input terminal, and is disposed in the vicinity of the amplifying element. A first temperature detection element whose output value changes according to the temperature of the element, and a current value of a current flowing through the amplifying element based on the output value of the first temperature detection element And a control unit that generates a voltage and applies the voltage to the input of the amplifying element.

  According to the amplifying device of the first aspect, the first temperature detecting element whose output value changes according to the temperature of the amplifying element is arranged in the vicinity of the amplifying element. And a control part produces | generates the voltage for making the electric current value of the electric current which flows through an amplification element approach a predetermined value based on the output value of a 1st temperature detection element, and applies the said voltage to the input of an amplification element. When the drain current is excessive due to the difference in element characteristics, the temperature of the amplifying element becomes relatively high, and thus the first temperature detecting element detects a relatively high temperature of the amplifying element. Therefore, when an output value indicating a relatively high temperature is input from the first temperature detection element, the control unit is configured to increase the drain current of the amplifying element relatively small according to the output value. Generates a voltage that acts in a direction approaching the value. On the other hand, when the drain current is excessively low due to the difference in element characteristics, the temperature of the amplifying element becomes relatively low. Therefore, the first temperature detecting element detects a relatively low temperature of the amplifying element. Therefore, when an output value indicating a relatively low temperature is input from the first temperature detecting element, the control unit is configured to increase the drain current of the amplifying element relatively large according to the output value. Generates a voltage that acts in a direction approaching the value. As a result, the drain current is adjusted so as to approach the predetermined value, so that it is possible to reduce the variation in drain current due to the difference in element characteristics.

  The amplifying apparatus according to the second aspect of the present invention is the amplifying apparatus according to the first aspect, in particular, the second temperature detecting element whose output value changes according to the temperature of the external environment where the amplifying apparatus is installed. In addition, the control unit may be configured such that the temperature of the external environment is based on the output value of the first temperature detection element and the output value of the second temperature detection element. The voltage is generated by eliminating or reducing the influence on the voltage.

  According to the amplification device according to the second aspect, the output value of the second temperature detection element changes according to the temperature of the external environment where the amplification device is installed. The control unit eliminates or reduces the influence of the temperature of the external environment on the first temperature detection element based on the output value of the first temperature detection element and the output value of the second temperature detection element. Generate voltage. Therefore, even when the first temperature detection element is affected by the temperature of the external environment, the control unit generates a voltage that eliminates or reduces the influence, and thereby the drain current due to the difference in element characteristics is reduced. Variation can be effectively reduced.

  An amplifying device according to a third aspect of the present invention, in the amplifying device according to the second aspect, further includes a heat radiating plate on which the amplifying device is arranged, and the second temperature detecting element is on the heat radiating plate. It is characterized by being arranged.

  According to the amplification device according to the third aspect, the second temperature detection element is disposed on the heat sink on which the amplification device is disposed. The influence of the temperature of the external environment on the first temperature detection element is mainly caused by the external environment via the heat sink. Therefore, by placing the second temperature detection element on the heat sink, Thus, the temperature of the external environment that affects the first temperature detection element can be detected with high accuracy by the second temperature detection element disposed on the heat sink.

  An amplifying device according to a fourth aspect of the present invention is the amplifying device according to the first aspect, in which the amplifying element includes a gate electrode connected to the input terminal, a drain electrode connected to the output terminal, , A FET having a source electrode, the control unit is an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, and the drain electrode is connected to a power supply terminal for supplying a power supply potential, The source electrode is connected to a ground terminal for applying a ground potential, the inverting input terminal is connected to the first temperature detection element, and a constant voltage value is input to the non-inverting input terminal. The output terminal of the operational amplifier is connected to the gate electrode.

  According to the amplification device according to the fourth aspect, the amplification device according to the first aspect can be realized with a relatively simple circuit configuration. In addition, when compared with an amplifying apparatus having a circuit configuration in which a resistance element for measuring a drain current is inserted in a path between a power supply terminal and a drain electrode and a gate voltage is controlled based on a voltage across the resistance element, the resistance element In addition to avoiding a decrease in efficiency due to power consumption at the same time and avoiding a decrease in drain voltage due to a voltage drop in the resistance element, avoiding a decrease in saturation output of the amplifier due to a decrease in drain voltage it can.

  An amplifying device according to a fifth aspect of the present invention is the amplifying device according to the second or third aspect, in which the amplifying element is connected to the gate electrode connected to the input terminal and the output terminal. The FET includes a drain electrode and a source electrode, the control unit is an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, and the drain electrode is connected to a power supply terminal that supplies a power supply potential. The source electrode is connected to a ground terminal for applying a ground potential, the inverting input terminal is connected to the first temperature detecting element, and the non-inverting input terminal is connected to the second terminal. The operational amplifier is connected to a temperature detection element, and the output terminal of the operational amplifier is connected to the gate electrode.

  According to the amplification device according to the fifth aspect, the amplification device according to the second or third aspect can be realized with a relatively simple circuit configuration. In addition, when compared with an amplifying apparatus having a circuit configuration in which a resistance element for measuring a drain current is inserted in a path between a power supply terminal and a drain electrode and a gate voltage is controlled based on a voltage across the resistance element, the resistance element In addition to avoiding a decrease in efficiency due to power consumption at the same time and avoiding a decrease in drain voltage due to a voltage drop in the resistance element, avoiding a decrease in saturation output of the amplifier due to a decrease in drain voltage it can.

  An amplifying device according to a sixth aspect of the present invention includes a gate electrode, a drain electrode connected to a power supply terminal for supplying a power supply potential, and a source electrode connected to a ground terminal for supplying a ground potential, and an input terminal By amplifying the input signal input to the gate electrode from the FET, the FET is inserted in the path between the power supply terminal and the drain electrode, and connected to the power supply terminal. A resistance element having a first end and a second end connected to the drain electrode; an inverting input terminal connected to the first end; a non-inverting input terminal connected to the second end; An operational amplifier having an output terminal connected to a gate electrode, wherein the operational amplifier has a drain that flows through the drain electrode based on a voltage value of the second terminal input to the non-inverting input terminal. It is characterized in that for outputting a voltage to approximate the current value of the current to the default value from the output terminal.

  According to the amplifying device of the sixth aspect, when the drain current is excessive due to the difference in element characteristics, the voltage drop in the resistance element becomes large, and the voltage value of the non-inverting input terminal of the operational amplifier Therefore, a relatively small input voltage is input between the non-inverting input terminal and the inverting input terminal of the operational amplifier. Therefore, when a relatively small input voltage is input, the operational amplifier generates a voltage that acts in a direction approaching a predetermined value by increasing the drain current of the amplifying element relatively small according to the voltage value. . On the other hand, if the drain current is too low due to the difference in device characteristics, the voltage drop at the resistance element becomes smaller and the voltage value at the non-inverting input terminal of the operational amplifier becomes larger. A relatively large input voltage is input between the terminal and the inverting input terminal. Therefore, when a relatively large input voltage is input, the operational amplifier generates a voltage that acts in a direction approaching a predetermined value by increasing the drain current of the amplifying element relatively large according to the voltage value. . As a result, the drain current is adjusted so as to approach the predetermined value, so that it is possible to reduce the variation in drain current due to the difference in element characteristics.

  An amplifying apparatus according to a seventh aspect of the present invention is characterized in that, in the amplifying apparatus according to the sixth aspect, in particular, the amplifying apparatus further includes a smoothing circuit interposed in a path between the output terminal and the gate electrode. It is what.

  According to the amplifying device of the seventh aspect, the smoothing circuit is inserted in the path between the output terminal of the operational amplifier and the gate electrode of the FET. Therefore, even when a high-frequency input signal is input to the FET, the voltage output from the operational amplifier and applied to the gate electrode for adjusting the drain current increases or decreases at a high frequency with the high-frequency input signal. Can be avoided.

  According to an eighth aspect of the present invention, there is provided a radio communication apparatus comprising: the amplifying apparatus according to the first or sixth aspect; and an antenna that transmits an output signal output from the amplifying apparatus as a radio signal. It is what.

  According to the radio communication apparatus according to the eighth aspect, the variation in drain current due to the difference in characteristics of the amplifying elements is automatically reduced in the amplifying apparatus, so that individual adjustment for each product is not necessary and It is possible to shorten the period and reduce the manufacturing cost.

  ADVANTAGE OF THE INVENTION According to this invention, the amplifier which can reduce the dispersion | variation in drain current resulting from the difference in element characteristics, and a radio | wireless communication apparatus provided with the same can be obtained.

It is a figure which shows typically the whole structure of a base station apparatus. It is a figure which simplifies and shows the structure of the amplifier which concerns on the 1st Embodiment of this invention. It is a figure which shows the structural example of the amplification element shown in FIG. It is a figure which shows an example of the voltage waveform in each part of an amplifier. It is a figure which simplifies and shows the structure of the amplifier which concerns on the 2nd Embodiment of this invention. It is a figure which simplifies and shows the structure of the amplifier which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows typically the external appearance structure of an amplifier. It is sectional drawing which shows typically the external appearance structure of an amplifier.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

  FIG. 1 is a diagram schematically illustrating the overall configuration of the base station apparatus 1. The base station apparatus 1 is a radio base station apparatus that supports communication standards such as LTE (Long Term Evolution), W-CDMA (Wideband Code Division Multiple Access), or WiMAX (Worldwide Interoperability for Microwave Access). And the like, and a radio communication device 6 connected to the base station main unit 2 via a communication cable 4 such as an optical fiber. The wireless communication device 6 includes an amplifying device 3 such as an RRH (Remote Radio Head) and an antenna 5 connected to the amplifying device 3. By separating the radio communication device 6 and the base station main body device 2, the degree of freedom of installation of the base station main body device 2 can be increased. In addition, by mounting the amplification device 3 in the wireless communication device 6, it is possible to reduce cable loss between the amplification device 3 and the antenna 5.

  Hereinafter, various configurations of the amplifying apparatus 3 according to the embodiment of the present invention will be described.

<First Embodiment>
FIG. 2 is a diagram showing a simplified configuration of the amplifying apparatus 3A according to the first embodiment of the present invention. The amplification device 3A includes an input terminal 12, a ground terminal 13, an output terminal 14, a power supply terminal 15, an amplification element 10, an operational amplifier 11 as a control unit, a smoothing circuit 17, and resistance elements 16, 60, and 61. ing.

  FIG. 3 is a diagram illustrating a configuration example of the amplifying element 10 illustrated in FIG. 2. The amplifying element 10 is an arbitrary FET (Field-Effect-Transistor), and is an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect-Transistor) 30 in the example of FIG. The MOSFET 30 has a gate electrode G, a drain electrode D, and a source electrode S. In the N-channel MOSFET 30, the drain current (that is, the current flowing from the drain electrode D to the source electrode S) increases as the gate voltage (that is, the potential of the gate electrode G with respect to the potential of the source electrode S) increases.

  With reference to FIG. 2, the gate electrode G of the amplifying element 10 is connected to the input terminal 12. The drain electrode D is connected to the output terminal 14 and is connected to the power supply terminal 15 via the resistance element 16. The source electrode S is connected to the ground terminal 13.

The input terminal 12 receives a high frequency input signal S1. The input signal S1 is input from the base station main unit 2 shown in FIG. A ground potential GND is applied to the ground terminal 13. The output terminal 14 is connected to the antenna 5. The power supply terminal 15 is given a predetermined power supply potential _Vps . The amplifying element 10 outputs an output signal S2 from the output terminal 14 by amplifying the input signal S1 input to the input terminal 12. The output signal S2 is output from the output terminal 14 toward the antenna 5 and transmitted from the antenna 5 as a radio signal.

  The resistance element 16 is inserted in a path between the power supply terminal 15 and the drain electrode D of the amplification element 10. That is, the first end 20 of the resistance element 16 is connected to the power supply terminal 15, and the second end 21 is connected to the drain electrode D.

  The operational amplifier 11 includes a non-inverting input terminal 22, an inverting input terminal 23, and an output terminal 24. The non-inverting input terminal 22 is connected to the second end 21 of the resistance element 16. The inverting input terminal 23 is connected to the first end 20 of the resistance element 16. The output terminal 24 is connected to the gate electrode G of the amplifying element 10 via the smoothing circuit 17. That is, the smoothing circuit 17 is inserted in the path between the output terminal 24 and the gate electrode G. The resistance element 60 is connected between the inverting input terminal 23 and the first end 20, and the resistance element 61 is connected between the inverting input terminal 23 and the output terminal 24.

  Hereinafter, the operation of the amplifying apparatus 3A shown in FIG. 2 will be described.

  FIG. 4 is a diagram illustrating an example of a voltage waveform in each part of the amplification device 3A. (A) shows the waveform of the voltage value V0 of the input signal S1, (B) shows the waveform of the voltage value V1 input to the non-inverting input terminal 22 of the operational amplifier 11, and (C). Shows the waveform of the output voltage V2 of the operational amplifier 11, and (D) shows the waveform of the output voltage V3 of the smoothing circuit 17. The output voltage V3 of the smoothing circuit 17 acts as a drain current adjustment bias voltage applied to the gate electrode G.

  When the input signal S1 is input from the input terminal 12 to the gate electrode G, the drain current Id corresponding to the envelope of the voltage waveform of the input signal S1 (indicated by a one-dot chain line in FIG. 4A) is supplied to the power supply terminal 15 To the ground terminal 13 through the resistance element 16, the drain electrode D, and the source electrode S in this order. Accordingly, a voltage corresponding to the value of the flowing drain current Id is generated at both ends of the resistance element 16 (that is, between the first end 20 and the second end 21). The larger the value of the drain current Id, the larger the voltage across the resistive element 16, and the smaller the value of the drain current Id, the smaller the voltage across the resistive element 16.

Since the second end 21 of the resistive element 16 is connected to the non-inverting input terminal 22 of the operational amplifier 11, a voltage value V 1 obtained by subtracting the voltage drop at the resistive element 16 from the power supply potential V _ps is a non-inverting input terminal 22. Is input. Therefore, the voltage value V1 decreases as the value of the drain current Id increases, and the voltage value V1 increases as the value of the drain current Id decreases.

  The operational amplifier 11 outputs an output voltage V2 corresponding to the input voltage (voltage between the non-inverting input terminal 22 and the inverting input terminal 23). In the amplifying apparatus 3A according to the present embodiment, the value of the output voltage V2 increases as the value of the input voltage increases (that is, the voltage value V1 increases), and the value of the input voltage decreases (that is, the voltage value V1 decreases). The operational amplifier 11 is designed so that the value of the output voltage V2 becomes small. Therefore, the value of the output voltage V2 decreases as the value of the drain current Id increases, and the value of the output voltage V2 increases as the value of the drain current Id decreases.

  The smoothing circuit 17 smoothes the output voltage V2 input from the operational amplifier 11 for a predetermined smoothing period (for example, 5 ms), thereby generating the output voltage V3 having a reduced frequency (ideally DC). Output. As a result, an output voltage V3 as a bias voltage superimposed on the gate voltage is applied to the gate electrode G. Similar to the output voltage V2, the value of the output voltage V3 decreases as the value of the drain current Id increases, and increases as the value of the drain current Id decreases. Therefore, in the amplifying device 3A in which the MOSFET 30 in which the excessive drain current Id flows is used, the drain current increases relatively small when the relatively small output voltage V3 is applied to the gate electrode G. On the other hand, in the amplifying device 3A in which the MOSFET 30 in which the excessively small drain current Id flows is used, when the relatively large output voltage V3 is applied to the gate electrode G, the drain current increases relatively. When the drain current Id flowing before application of the output voltage V3 is set smaller than a predetermined value corresponding to the voltage value V0, and the drain current Id before application of the output voltage V3 is excessive, a relatively small output By increasing the drain current Id relatively small by applying the voltage V3, the drain current Id after applying the output voltage V3 can be brought close to a predetermined value. On the other hand, if the drain current Id before application of the output voltage V3 is excessively small, the drain current Id after application of the output voltage V3 is increased by relatively increasing the drain current Id by applying a relatively large output voltage V3. Id can be close to the default value. As a result, the value of the drain current Id after the application of the output voltage V3 is adjusted so as to approach the predetermined value regardless of variations in element characteristics due to the manufacturing process.

  As an example, the amplifying device 3A performs a setting process of the output voltage V3 as a bias voltage at a timing when a predetermined input signal S1 whose voltage waveform and voltage value are known (hereinafter referred to as a pilot signal) is input. Do. A specified value of the drain current Id corresponding to the pilot signal voltage value V0 is set in advance, and the input voltage of the operational amplifier 11 when the pilot signal is input based on the specified value and the resistance value of the resistance element 16 Are set in advance. When the MOSFET 30 through which an excessive drain current Id flows due to variations in element characteristics is used as the amplifying element 10, the input voltage of the operational amplifier 11 when the pilot signal is input is smaller than the target value. On the other hand, when the MOSFET 30 in which the excessive drain current Id flows is used as the amplifying element 10, the input voltage of the operational amplifier 11 when the pilot signal is input becomes larger than the target value. When the input voltage is smaller than the target value, the operational amplifier 11 outputs the output voltage V2 that acts in a direction approaching the predetermined value by increasing the drain current Id relatively small, while the input voltage is lower than the target value. Is larger, the output voltage V2 acting in the direction approaching the predetermined value is output by increasing the drain current Id relatively large. Then, when the output voltage V3 corresponding to the output voltage V2 is applied to the gate electrode G, the drain current Id approaches the predetermined value. Even after the transmission period of the pilot signal ends, the application of the output voltage V3 to the gate electrode G is continued.

  As described above, according to the amplifying apparatus 3A according to the present embodiment, when the drain current Id is excessive due to the difference in element characteristics, the voltage drop in the resistance element 16 increases and the voltage value V1 is Therefore, a relatively small input voltage is input between the non-inverting input terminal 22 and the inverting input terminal 23 of the operational amplifier 11. Therefore, when a relatively small input voltage is input, the operational amplifier 11 generates an output voltage V2 for increasing the drain current Id of the amplifying element 10 relatively small according to the voltage value. On the other hand, when the drain current Id is too small due to the difference in element characteristics, the voltage drop at the resistance element 16 becomes small and the voltage value V1 becomes large. A relatively large input voltage is input between the input terminals 23. Therefore, when a relatively large input voltage is input, the operational amplifier 11 generates an output voltage V2 for increasing the drain current Id of the amplifying element 10 relatively large according to the voltage value. As a result, the drain current Id is adjusted so as to approach the predetermined value, so that it is possible to reduce the variation in the drain current Id caused by the difference in element characteristics.

  Further, according to the amplification device 3 </ b> A according to the present embodiment, the smoothing circuit 17 is inserted in the path between the output terminal 24 of the operational amplifier 11 and the gate electrode G of the amplification element 10. Therefore, even when the high-frequency input signal S1 is input to the amplifying element 10, the bias voltage output from the operational amplifier 11 and applied to the gate electrode G for adjusting the drain current Id is the high-frequency input signal. It is possible to avoid a situation where the frequency increases or decreases with S1.

  Further, according to the wireless communication device 6 according to the present embodiment, the variation in the drain current Id caused by the difference in the characteristics of the amplifying element 10 is automatically reduced in the amplifying device 3A. Adjustment is not required, and the manufacturing period can be shortened and the manufacturing cost can be reduced.

<Second Embodiment>
According to the amplifying device 3A according to the first embodiment, the resistive element 16 is inserted in the path between the power supply terminal 15 and the drain electrode D. Therefore, wasteful power consumption due to heat generation of the resistance element 16 occurs. In addition, since the drain voltage drops with the voltage drop at the resistance element 16, the saturation output of the amplifying device decreases. In the second embodiment, an amplifying apparatus in which such inconvenience is improved will be described.

  FIG. 5 is a diagram showing a simplified configuration of the amplifying device 3B according to the second embodiment of the present invention. The amplification device 3B includes an input terminal 12, a ground terminal 13, an output terminal 14, a power supply terminal 15, an amplification element 10, an operational amplifier 11, resistance elements 40, 62, and 63, and a temperature detection element 41. As the amplifying element 10, a MOSFET or the like can be used as in the first embodiment.

  The temperature detection element 41 is disposed in the vicinity (including contact) of the amplification element 10 so that the temperature of the amplification element 10 can be detected. As the temperature detection element 41, an arbitrary element whose output value changes according to temperature, such as a thermistor, a thermocouple, or a transistor, can be used. In the following example, a thermistor is used as the temperature detection element 41. The resistance value of the thermistor decreases as the temperature of the amplifying element 10 increases. On the other hand, the resistance value of the thermistor increases as the temperature of the amplifying element 10 decreases.

  The gate electrode G of the amplifying element 10 is connected to the input terminal 12. The drain electrode D is connected to the output terminal 14 and the power supply terminal 15. The source electrode S is connected to the ground terminal 13.

The input terminal 12 receives a high frequency input signal S1. A ground potential GND is applied to the ground terminal 13. The output terminal 14 is connected to the antenna 5. The power supply terminal 15 is given a predetermined power supply potential _Vps . The amplifying element 10 outputs an output signal S2 from the output terminal 14 by amplifying the input signal S1 input to the input terminal 12. The output signal S2 is output from the output terminal 14 toward the antenna 5 and transmitted from the antenna 5 as a radio signal.

  The operational amplifier 11 includes a non-inverting input terminal 22, an inverting input terminal 23, and an output terminal 24. The non-inverting input terminal 22 is connected to the power supply terminal 15 through the resistance element 40. The inverting input terminal 23 is connected to the power supply terminal 15 via the temperature detection element 41. The output terminal 24 is connected to the gate electrode G of the amplifying element 10. The resistance element 62 is connected between the non-inverting input terminal 22 and the ground potential, and the resistance element 63 is connected between the inverting input terminal 23 and the output terminal 24.

  Hereinafter, the operation of the amplifying apparatus 3B shown in FIG. 5 will be described.

  When the input signal S1 is input from the input terminal 12 to the gate electrode G, the drain current Id corresponding to the voltage value V0 of the input signal S1 passes through the drain electrode D and the source electrode S in this order from the power supply terminal 15. And flows to the ground terminal 13. Accordingly, the amplifying element 10 generates heat according to the value of the flowing drain current Id. The heat generation of the amplifying element 10 increases as the value of the drain current Id increases. Therefore, the resistance value of the temperature detection element 41 is small. On the other hand, the smaller the value of the drain current Id, the smaller the heat generation of the amplifying element 10. Therefore, the resistance value of the temperature detection element 41 is increased.

The potential of the non-inverting input terminal 22 of the operational amplifier 11 is a potential (a constant value) obtained by subtracting the voltage drop at the resistance element 40 from the power supply potential _Vps . The potential of the inverting input terminal 23 is a potential obtained by subtracting the voltage drop at the temperature detecting element 41 from the power supply potential _Vps . The difference between the potential of the non-inverting input terminal 22 and the potential of the inverting input terminal 23 becomes the input voltage V5 of the operational amplifier 11. Here, the smaller the resistance value of the temperature detection element 41, the smaller the voltage drop at the temperature detection element 41, and the greater the resistance value of the temperature detection element 41, the greater the voltage drop at the temperature detection element 41. Therefore, as the value of the drain current Id increases, the temperature of the amplifying element 10 increases, the resistance value of the temperature detecting element 41 decreases, the voltage drop at the temperature detecting element 41 decreases, and the potential of the inverting input terminal 23 becomes Since it becomes high, the value of the input voltage V5 becomes small. On the other hand, the smaller the drain current Id is, the lower the temperature of the amplifying element 10 is, the resistance value of the temperature detecting element 41 is increased, the voltage drop at the temperature detecting element 41 is increased, and the potential of the inverting input terminal 23 is Since it becomes low, the value of the input voltage V5 becomes large.

  The operational amplifier 11 outputs an output voltage V6 corresponding to the input voltage V5. As a result, an output voltage V6 as a bias voltage superimposed on the gate voltage is applied to the gate electrode G. In the amplifying apparatus 3B according to the present embodiment, the operational amplifier 11 is configured such that the value of the output voltage V6 increases as the value of the input voltage V5 increases, and the value of the output voltage V6 decreases as the value of the input voltage V5 decreases. Designed. Therefore, the value of the output voltage V6 decreases as the value of the drain current Id increases, and the value of the output voltage V6 increases as the value of the drain current Id decreases.

  Accordingly, in the amplifying device 3B in which the MOSFET 30 in which the excessive drain current Id flows is used, the drain current increases relatively small when the relatively small output voltage V6 is applied to the gate electrode G. On the other hand, in the amplifying device 3B in which the MOSFET 30 in which the excessively small drain current Id flows is used, when the relatively large output voltage V6 is applied to the gate electrode G, the drain current increases relatively. If the drain current Id flowing before application of the output voltage V6 is set smaller than a predetermined value corresponding to the voltage value V0, and the drain current Id before application of the output voltage V6 is excessive, a relatively small output By increasing the drain current Id relatively small by applying the voltage V6, the drain current Id after the application of the output voltage V6 can be brought close to a predetermined value. On the other hand, if the drain current Id before application of the output voltage V6 is excessively small, the drain current Id after application of the output voltage V6 is increased by relatively increasing the drain current Id by applying a relatively large output voltage V6. Id can be close to the default value. As a result, the value of the drain current Id after the application of the output voltage V6 is adjusted so as to approach the predetermined value regardless of variations in element characteristics due to the manufacturing process.

  As an example, the amplifying apparatus 3B performs setting processing of the output voltage V6 as a bias voltage at a predetermined timing (for example, a specific time zone at midnight) where the communication data amount is constant. A predetermined value of the drain current Id corresponding to a certain amount of communication data and a target value of the input voltage V5 of the operational amplifier 11 corresponding to the predetermined value are set in advance. When the MOSFET 30 in which an excessive drain current Id flows due to variations in element characteristics is used as the amplifying element 10, the input voltage V5 when the communication data amount is constant is smaller than the target value. On the other hand, when the MOSFET 30 in which the excessive drain current Id flows is used as the amplifying element 10, the input voltage V5 when the communication data amount is constant is larger than the target value. When the input voltage V5 is smaller than the target value, the operational amplifier 11 outputs an output voltage V6 that acts in a direction approaching a predetermined value by increasing the drain current Id relatively small, while the input voltage V5 is the target voltage V5. When the value is larger than the value, the output voltage V6 acting in the direction approaching the predetermined value is output by increasing the drain current Id relatively large. Then, when the output voltage V6 is applied to the gate electrode G, the drain current Id approaches a predetermined value. Even after the setting process of the output voltage V6 is completed, the application of the output voltage V6 to the gate electrode G is continued.

  As described above, according to the amplification device 3B according to the present embodiment, the temperature detection element 41 whose output value (voltage drop amount) changes according to the temperature of the amplification element 10 is disposed in the vicinity of the amplification element 10. Yes. The operational amplifier 11 generates an output voltage V6 for making the current value of the drain current Id flowing through the amplifying element 10 close to a predetermined value based on the output value of the temperature detecting element 41, and the output voltage V6 is used as the amplifying element 10. To the gate electrode G. When the drain current Id is excessive due to the difference in element characteristics, the temperature of the amplifying element 10 becomes relatively high, and thus the temperature detecting element 41 detects a relatively high temperature of the amplifying element 10. Therefore, when an output value indicating a relatively high temperature is input from the temperature detecting element 41, the operational amplifier 11 outputs an output for increasing the drain current Id of the amplifying element 10 relatively small in accordance with the output value. A voltage V6 is generated. On the other hand, when the drain current Id is excessively low due to the difference in element characteristics, the temperature of the amplifying element 10 is relatively low, so that the temperature detecting element 41 detects a relatively low temperature of the amplifying element 10. . Therefore, when an output value indicating a relatively low temperature is input from the temperature detecting element 41, the operational amplifier 11 outputs an output for increasing the drain current Id of the amplifying element 10 relatively large according to the output value. A voltage V6 is generated. As a result, the drain current Id is adjusted so as to approach the predetermined value, so that it is possible to reduce the variation in the drain current Id caused by the difference in element characteristics.

  Further, according to the amplifying apparatus 3B according to the present embodiment, it is possible to realize automatic adjustment of the drain current Id with a relatively simple circuit configuration using the temperature detecting element 41, the operational amplifier 11, and the like. Further, since the resistance element 16 for drain current measurement (see FIG. 2) is not inserted in the path between the power supply terminal 15 and the drain electrode D, the efficiency is reduced due to power consumption in the resistance element 16. In addition to being able to avoid this, it is possible to avoid a drop in the drain voltage due to a voltage drop in the resistance element 16, and thus it is possible to avoid a decrease in the saturation output of the amplifier due to the drop in the drain voltage.

<Third Embodiment>
According to the amplifying apparatus 3B according to the second embodiment, when the temperature detecting element 41 detects the temperature of the amplifying element 10, there is a possibility of being affected by the temperature of the external environment where the amplifying apparatus 3B is installed. When the temperature detection element 41 is affected by the temperature of the external environment, the adjustment accuracy of the drain current Id is lowered. In the third embodiment, an amplifying apparatus in which such an inconvenience is improved will be described.

  FIG. 6 is a diagram showing a simplified configuration of an amplifying apparatus 3C according to the third embodiment of the present invention. The amplification device 3C includes an input terminal 12, a ground terminal 13, an output terminal 14, a power supply terminal 15, an amplification element 10, an operational amplifier 11, resistance elements 62 and 63, and temperature detection elements 41 and 42. As the amplifying element 10, a MOSFET or the like can be used as in the first embodiment.

  The temperature detection element 41 is disposed in the vicinity (including contact) of the amplification element 10 so that the temperature of the amplification element 10 can be detected. The temperature detection element 42 is disposed on a heat sink 50 (see FIGS. 7 and 8 described later) on which the amplification device 3C is disposed so that the temperature of the external environment can be detected. As shown in FIG. 6, since the temperature detecting element 42 needs to be connected between the operational amplifier 11 and the power supply terminal 15, the circuit board 53 (FIG. 7, FIG. 8), the temperature detecting element 42 may be disposed at a position away from the amplifying element 10 (that is, a position that is not easily affected by the heat generated by the amplifying element 10).

  7 and 8 are a perspective view and a cross-sectional view, respectively, schematically showing the external configuration of the amplification device 3C. A circuit board 52 for a power supply circuit, a circuit board 53 for an amplifier circuit, and a circuit board 54 for signal processing are accommodated in a housing including the heat radiating plate 50 and the case lid 51. On the circuit board 53, the amplification element 10 and the temperature detection element 41 are mounted in the vicinity thereof. Although not shown in FIGS. 7 and 8, the operational amplifier 11 and the resistance elements 62 and 63 shown in FIG. 6 are also mounted on the circuit board 53. As shown in FIG. 8, the temperature detection element 42 is disposed on a portion of the inner surface of the heat radiating plate 50 where the circuit board 53 is not disposed.

  As the temperature detection elements 41 and 42, any element whose output value changes according to temperature, such as a thermistor, a thermocouple, or a transistor, can be used. In the following example, a thermistor is used as the temperature detection elements 41 and 42. The higher the temperature of the amplifying element 10 and the external environment, the smaller the resistance value of the thermistor. On the other hand, the lower the temperature of the amplifying element 10 and the external environment, the larger the resistance value of the thermistor.

  Referring to FIG. 6, the gate electrode G of the amplifying element 10 is connected to the input terminal 12. The drain electrode D is connected to the output terminal 14 and the power supply terminal 15. The source electrode S is connected to the ground terminal 13.

The input terminal 12 receives a high frequency input signal S1. A ground potential GND is applied to the ground terminal 13. The output terminal 14 is connected to the antenna 5. The power supply terminal 15 is given a predetermined power supply potential _Vps . The amplifying element 10 outputs an output signal S2 from the output terminal 14 by amplifying the input signal S1 input to the input terminal 12. The output signal S2 is output from the output terminal 14 toward the antenna 5 and transmitted from the antenna 5 as a radio signal.

  The operational amplifier 11 includes a non-inverting input terminal 22, an inverting input terminal 23, and an output terminal 24. The non-inverting input terminal 22 is connected to the power supply terminal 15 via the temperature detection element 42. The inverting input terminal 23 is connected to the power supply terminal 15 via the temperature detection element 41. The output terminal 24 is connected to the gate electrode G of the amplifying element 10.

  Hereinafter, the operation of the amplifying apparatus 3C shown in FIG. 6 will be described.

  When the input signal S1 is input from the input terminal 12 to the gate electrode G, the drain current Id corresponding to the voltage value V0 of the input signal S1 passes through the drain electrode D and the source electrode S in this order from the power supply terminal 15. And flows to the ground terminal 13. Accordingly, the amplifying element 10 generates heat according to the value of the flowing drain current Id. The heat generation of the amplifying element 10 increases as the value of the drain current Id increases. Therefore, the resistance value of the temperature detection element 41 is small. On the other hand, the smaller the value of the drain current Id, the smaller the heat generation of the amplifying element 10. Therefore, the resistance value of the temperature detection element 41 is increased. Further, as shown in FIG. 8, since the temperature detecting element 42 is disposed on the heat sink 50, the higher the temperature of the external environment, the higher the temperature of the heat sink 50, and the resistance value of the temperature detecting element 42 is Get smaller. On the other hand, the lower the temperature of the external environment, the lower the temperature of the heat sink 50 and the higher the resistance value of the temperature detecting element 42.

The potential of the non-inverting input terminal 22 of the operational amplifier 11 is a potential obtained by subtracting the voltage drop at the temperature detection element 42 from the power supply potential _Vps . The potential of the inverting input terminal 23 is a potential obtained by subtracting the voltage drop at the temperature detecting element 41 from the power supply potential _Vps . The difference between the potential of the non-inverting input terminal 22 and the potential of the inverting input terminal 23 becomes the input voltage V8 of the operational amplifier 11.

  As the temperature of the external environment is higher, the resistance value of the temperature detection element 42 becomes smaller and the voltage drop at the temperature detection element 42 becomes smaller. Therefore, the potential of the non-inverting input terminal 22 becomes higher. On the other hand, as the temperature of the external environment is lower, the resistance value of the temperature detection element 42 is increased and the voltage drop at the temperature detection element 42 is increased, so that the potential of the non-inverting input terminal 22 is decreased. Further, as described in the second embodiment, the potential of the inverting input terminal 23 increases as the value of the drain current Id increases, and the potential of the inverting input terminal 23 decreases as the value of the drain current Id decreases.

  Here, even if the temperature detecting element 41 is affected by the temperature of the external environment and the potential of the inverting input terminal 23 fluctuates, the temperature detecting element 42 detects the same effect as the temperature detecting element 41 receives. This is reflected in the potential of the non-inverting input terminal 22. Therefore, even when the temperature detection element 41 is affected by the temperature of the external environment, the influence is eliminated or reduced from the input voltage V8. In consideration of the difference in the sensitivity of the temperature of the external environment between the temperature detection element 41 and the temperature detection element 42, the output value of at least one of the temperature detection elements 41 and 42 is multiplied by a correction coefficient. May be.

  The operational amplifier 11 outputs an output voltage V9 corresponding to the input voltage V8. As a result, an output voltage V9 as a bias voltage superimposed on the gate voltage is applied to the gate electrode G. In the amplifying apparatus 3C according to the present embodiment, the operational amplifier 11 is configured such that the value of the output voltage V9 increases as the value of the input voltage V8 increases, and the value of the output voltage V9 decreases as the value of the input voltage V8 decreases. Designed. Therefore, the value of the output voltage V9 decreases as the value of the drain current Id increases, and the value of the output voltage V9 increases as the value of the drain current Id decreases.

  Therefore, in the amplifying device 3C in which the MOSFET 30 in which the excessive drain current Id flows is used, the drain current increases relatively small when the relatively small output voltage V9 is applied to the gate electrode G. On the other hand, in the amplifying device 3C in which the MOSFET 30 in which the excessive drain current Id flows is used, the drain current increases relatively large when the relatively large output voltage V9 is applied to the gate electrode G. If the drain current Id flowing before application of the output voltage V9 is set smaller than a predetermined value corresponding to the voltage value V0, and the drain current Id before application of the output voltage V9 is excessive, a relatively small output By increasing the drain current Id relatively small by applying the voltage V9, the drain current Id after applying the output voltage V9 can be brought close to a predetermined value. On the other hand, when the drain current Id before the application of the output voltage V9 is excessively small, the drain current Id after the application of the output voltage V9 is increased by relatively increasing the drain current Id by applying a relatively large output voltage V9. Id can be close to the default value. As a result, the value of the drain current Id after application of the output voltage V9 is adjusted so as to approach the predetermined value regardless of variations in element characteristics due to the manufacturing process.

  As an example, the amplifying apparatus 3C performs setting processing of the output voltage V9 as a bias voltage at a predetermined timing (for example, a specific time zone at midnight) when the communication data amount is constant. A predetermined value of the drain current Id corresponding to a certain amount of communication data and a target value of the input voltage V8 of the operational amplifier 11 corresponding to the predetermined value are set in advance. When the MOSFET 30 in which an excessive drain current Id flows due to variations in element characteristics is used as the amplifying element 10, the input voltage V8 when the communication data amount is constant is smaller than the target value. On the other hand, when the MOSFET 30 through which the excessive drain current Id flows is used as the amplifying element 10, the input voltage V8 when the communication data amount is constant becomes larger than the target value. When the input voltage V8 is smaller than the target value, the operational amplifier 11 outputs the output voltage V9 that acts in the direction of approaching the predetermined value by increasing the drain current Id relatively small, while the input voltage V8 is the target voltage V8. When the value is larger than the value, the output voltage V9 acting in a direction approaching the predetermined value is output by increasing the drain current Id relatively large. Then, when the output voltage V9 is applied to the gate electrode G, the drain current Id approaches a predetermined value. Even after the setting process of the output voltage V9 is completed, the application of the output voltage V9 to the gate electrode G is continued.

  As described above, according to the amplifying apparatus 3C according to the present embodiment, the output value (voltage drop amount) of the temperature detecting element 42 changes according to the temperature of the external environment where the amplifying apparatus 3C is installed. The operational amplifier 11 generates an output voltage V9 that eliminates or reduces the influence of the temperature of the external environment on the temperature detection element 41 based on the output value of the temperature detection element 41 and the output value of the temperature detection element 42. . Therefore, even when the temperature detection element 41 is affected by the temperature of the external environment, the operational amplifier 11 generates the output voltage V9 that eliminates or reduces the influence, thereby causing the drain current Id due to the difference in element characteristics. It is possible to effectively reduce the variation of.

  Further, according to the amplifying apparatus 3C according to the present embodiment, the temperature detection element 42 is disposed on the heat dissipation plate 50 where the amplifying apparatus 3C is disposed. The influence of the temperature of the external environment on the temperature detection element 41 is mainly caused by the external environment via the heat sink 50. Therefore, by disposing the temperature detection element 42 on the heat sink 50, the temperature of the external environment that affects the temperature detection element 41 via the heat sink 50 is increased by the temperature detection element 42 disposed on the heat sink 50. It becomes possible to detect with accuracy.

  In addition, according to the amplifying device 3C according to the present embodiment, the drain of the drain is achieved while eliminating or reducing the influence of the temperature of the external environment by a relatively simple circuit configuration using the temperature detection elements 41 and 42, the operational amplifier 11 and the like. Automatic adjustment of the current Id can be realized. Further, since the resistance element 16 for drain current measurement (see FIG. 2) is not inserted in the path between the power supply terminal 15 and the drain electrode D, the efficiency is reduced due to power consumption in the resistance element 16. In addition to being able to avoid this, it is possible to avoid a drop in the drain voltage due to a voltage drop in the resistance element 16, and thus it is possible to avoid a decrease in the saturation output of the amplifier due to the drop in the drain voltage.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.

3, 3A to 3C Amplifying device 5 Antenna 6 Wireless communication device 10 Amplifying element 11 Operational amplifier 12 Input terminal 13 Ground terminal 14 Output terminal 15 Power supply terminal 16 Resistance element 17 Smoothing circuit 22 Non-inverting input terminal 23 Inverting input terminal 24 Output terminal 30 MOSFET
41, 42 Temperature detection element 50 Heat sink

Claims (8)

An amplification element that outputs an output signal from the output terminal by amplifying the input signal input to the input terminal;
A first temperature detecting element disposed in the vicinity of the amplifying element, the output value of which varies according to the temperature of the amplifying element;
Based on the output value of the first temperature detection element, a control unit that generates a voltage for causing the current value of the current flowing through the amplification element to approach a predetermined value, and applies the voltage to the input of the amplification element; ,
An amplification device comprising: A second temperature detection element whose output value changes according to the temperature of the external environment in which the amplification device is installed;
The control unit is configured to influence the temperature of the external environment on the first temperature detection element based on the output value of the first temperature detection element and the output value of the second temperature detection element. The amplifying apparatus according to claim 1, wherein the voltage is generated by eliminating or reducing the voltage. A heat sink on which the amplifying device is disposed;
The amplifying apparatus according to claim 2, wherein the second temperature detection element is disposed on the heat radiating plate. The amplifying element is a FET (Field-Effect-Transistor) having a gate electrode connected to the input terminal, a drain electrode connected to the output terminal, and a source electrode,
The control unit is an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal,
The drain electrode is connected to a power supply terminal for supplying a power supply potential;
The source electrode is connected to a ground terminal for applying a ground potential;
The inverting input terminal is connected to the first temperature detection element;
A constant voltage value is input to the non-inverting input terminal,
The amplification device according to claim 1, wherein the output terminal of the operational amplifier is connected to the gate electrode. The amplifying element is a FET (Field-Effect-Transistor) having a gate electrode connected to the input terminal, a drain electrode connected to the output terminal, and a source electrode,
The control unit is an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal,
The drain electrode is connected to a power supply terminal for supplying a power supply potential;
The source electrode is connected to a ground terminal for applying a ground potential;
The inverting input terminal is connected to the first temperature detection element;
The non-inverting input terminal is connected to the second temperature detection element;
The amplification device according to claim 2, wherein the output terminal of the operational amplifier is connected to the gate electrode. A gate electrode, a drain electrode connected to a power supply terminal for supplying a power supply potential, and a source electrode connected to a ground terminal for supplying a ground potential, and amplifying an input signal input from the input terminal to the gate electrode FET (Field-Effect-Transistor) that outputs the output signal from the output terminal,
A resistance element having a first end inserted in a path between the power supply terminal and the drain electrode and connected to the power supply terminal; and a second end connected to the drain electrode;
An operational amplifier having an inverting input terminal connected to the first end, a non-inverting input terminal connected to the second end, and an output terminal connected to the gate electrode;
With
The operational amplifier outputs, from the output terminal, a voltage for bringing the current value of the drain current flowing through the drain electrode close to a predetermined value based on the voltage value of the second terminal input to the non-inverting input terminal. Amplification equipment.   The amplifying apparatus according to claim 6, further comprising a smoothing circuit interposed in a path between the output terminal and the gate electrode. An amplifying device according to claim 1 or 6,
An antenna for transmitting the output signal output from the amplification device as a radio signal;
A wireless communication device.

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