JP5088224B2 - Amplifying device and mounting base - Google Patents

Description

  The present invention relates to an amplifying device, and more particularly to an amplifying device having a distortion compensation mechanism for compensating for output waveform distortion of an amplifier caused by a temperature change.

  Conventionally, an amplifying apparatus having a distortion compensation mechanism for compensating for output waveform distortion of an amplifier due to a temperature change has been proposed (see, for example, Patent Document 1). In order to enable such distortion compensation, a conventional amplifying apparatus includes a semiconductor amplifier, a bias circuit, a temperature sensor that measures the ambient temperature of the amplifier, a control unit, and a correction voltage supply circuit that supplies a correction voltage to the bias circuit. Have

Here, the semiconductor amplifier has a field effect transistor (FET) as an amplifying element. The bias circuit supplies the amplifier with a gate bias voltage for determining the operating point of the field effect transistor included in the amplifier. The temperature sensor is arranged around the amplifier and measures the temperature around the amplifier. Based on the measurement result of the temperature sensor, the control unit sets a correction voltage in the correction voltage supply circuit by referring to a temperature compensation table in which a correction voltage value corresponding to the measured temperature is determined in advance. The correction voltage supply circuit is a D / A converter (DAC) in which a correction voltage as a digital value is set, or a capacitor that holds the correction voltage as an analog amount.
Japanese Utility Model Publication No. 62-151221

  The conventional amplifying apparatus having the above-described distortion compensation mechanism requires additional power for operating the temperature sensor and the control unit, and it is difficult to reduce power consumption.

  The present invention has been made based on the above-described knowledge, and an object thereof is to provide an amplifying device that can realize low power consumption of a distortion compensation mechanism.

  An amplification device according to one embodiment of the present invention includes an amplifier, a thermoelectric conversion unit, and a bias circuit. The amplifier has a field effect transistor as an amplifying element. The thermoelectric conversion unit generates a voltage signal by thermoelectric conversion using a temperature gradient generated by self-heating of the amplifier. Further, the bias circuit receives the voltage signal and increases or decreases the gate bias voltage applied to the transistor according to the magnitude of the voltage signal.

  The amplifying device according to one embodiment of the present invention described above supplies an analog voltage signal generated by thermoelectric conversion using a temperature gradient due to self-heating of an amplifier to a bias circuit as a control signal for adjusting a gate bias voltage. . In addition, the voltage signal generated by the thermoelectric converter is obtained by reusing the self-heating of the amplifier as electric energy. Therefore, the above-described amplifying device according to one embodiment of the present invention does not require power for operating the temperature sensor and the control unit that are necessary for the conventional amplifying device, which can contribute to low power consumption. .

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary for the sake of clarity.

FIG. 1 is a circuit block diagram of an amplifying apparatus 1 according to the present embodiment. The amplifier 11 is a semiconductor amplifier that amplifies, for example, a high-frequency signal (RF signal). The amplifier 11 amplifies the input voltage _VIN and outputs an output voltage _VOUT . The amplifier 11 has a FET 111 as an amplifying element.

  The thermoelectric converter 12 generates a thermoelectromotive force by thermoelectric conversion using a temperature gradient generated by the self-heating of the amplifier 11, and a voltage signal corresponding to the magnitude of the thermoelectromotive force is supplied to the bias circuit 13 as the control voltage Vc described above. Supply. That is, as the amount of heat generated by the amplifier 11 increases and the temperature gradient resulting from this increases, the control voltage Vc as the thermoelectromotive force gradually increases.

The bias circuit 13 supplies a gate bias voltage Vg that determines the operating point of the FET 111 included in the amplifier 11 to the gate of the FET 111. The bias circuit 13 is supplied with a control voltage Vc from a thermoelectric converter 12 described later, and increases or decreases the gate bias voltage Vg according to the magnitude of the control voltage Vc. More specifically, in order to suppress the voltage drop of the gate-source voltage V _GS of the FET 111 when the temperature of the amplifier 11 rises, the bias circuit 13 increases the control voltage Vc as the thermoelectromotive force as it increases. The gate bias voltage Vg is increased.

  An example of a specific configuration of the amplifier 11 and the bias circuit 13 is shown in FIG. FIG. 2 is a circuit diagram illustrating a configuration example of the amplifier 11 and the bias circuit 13. The amplifier 11 shown in FIG. 2 has an N-channel FET 111 as an amplifying element. The gate of the FET 111 is connected to the input matching circuit 112, and the drain is connected to the output matching circuit 113. In FIG. 2, capacitors C1 and C2 are coupling capacitors for cutting direct current (DC). The capacitor C3 is a bypass capacitor connected to the signal line of the drain power supply voltage Vd.

  The bias circuit 13 shown in FIG. 2 has an N-channel FET 131 that functions as a variable resistor in order to change the gate bias voltage Vg according to the magnitude of the control voltage Vc.

  The source of the FET 131 is connected to the gate of the FET 111 via an inductor LG for blocking a high frequency signal. The drain of the FET 131 is connected to the date bias power supply voltage VG via the gate bias resistor RG. The gate of the FET 131 is connected to the input terminal of the control voltage Vc supplied from the thermoelectric converter 12. The capacitor C4 is a bypass capacitor connected to the signal line of the gate power supply voltage VC. The capacitor C5 is a decoupling capacitor for blocking direct current provided between the drain of the FET 111 that is an amplifying element and the gate of the FET 131 that is a variable resistance element. Although FIG. 2 shows a configuration example in the case where the FETs 111 and 131 are N-channel FETs, it is needless to say that these may be replaced with P-channel FETs.

Next, the principle of output distortion compensation in the amplifying apparatus 1 shown in FIGS. 1 and 2 will be described below with reference to FIG. FIG. 5 is a graph showing distortion compensation characteristics of the amplifying apparatus 1. The horizontal axis in FIG. 5 is the input voltage _VIN . The vertical axis in FIG. 5 represents the third order inter-modulation distortion (IM3) of the surface temperature, the thermoelectromotive force, and the output waveform of the amplifier IC31.

When the input voltage _VIN supplied to the amplifier 11 increases, the gate current of the FET 111 that is an amplifying element increases. As a result, a voltage drop of the gate-source voltage V _GS of the FET 111 occurs. However, as shown in FIG. 5, since the amount of heat generated by the amplifier 11 is increased by the increase of the input voltage _VIN , the electromotive force generated by the thermoelectric converter 12, that is, the control voltage Vc also increases. Therefore, to become the control voltage Vc increased to the gate of the FET 131 that functions as a variable resistor is applied, the drain of the FET 131 - reduces the source resistance R _DS, an increase in the gate bias voltage Vg provided . The increase in the gate bias voltage Vg suppresses the voltage drop of the gate-source voltage V _GS of the FET 111 described above. As a result, as shown in FIG. 5, the gate current of the FET 111 is reduced, and deterioration of the distortion characteristics when the input voltage _VIN is large (at the time of large input power) can be suppressed.

  As described above, the amplifying apparatus 1 supplies the analog power signal obtained by thermoelectric conversion to the bias circuit 13 to use the analog voltage signal for adjusting the gate bias voltage Vg of the FET 111 included in the amplifier 11. . That is, since the amplifying apparatus 1 does not require the temperature sensor and the control unit that are necessary for the conventional amplifying apparatus, the power consumption can be reduced and the circuit scale can be reduced.

  Further, the power consumption of the bias circuit 13 shown in FIG. 2 is substantially zero until the gate current is generated in the FET 111. For this reason, by adopting the configuration of FIGS. 1 and 2, the power consumption of the entire amplifying apparatus 1 can be reduced.

  Subsequently, a specific configuration example of the thermoelectric conversion unit 12 capable of effectively generating a temperature gradient using the self-heating of the amplifier 11 will be described in detail below. FIG. 3 is a side sectional view showing the configuration of the amplifying apparatus 1.

  In FIG. 3, an amplifier IC (Integrated Circuit) 31 is an IC including the amplifier 11 described above. The control circuit IC32 is an IC including the bias circuit 13 described above. Of course, the mounting form of the amplifier 11 and the bias circuit 13 shown in FIG. 3 is an example. For example, the amplifier 11 and the bias circuit 13 may be formed on one chip, or may be integrated in one package by integrating a plurality of chips. The amplifier 11 and the bias circuit 13 may be divided into a plurality of IC packages, respectively. Further, the control circuit IC 32 including the bias circuit 13 may not be disposed on the mounting base 33 common with the amplifier IC 31 including the amplifier 11.

  In FIG. 3, the amplifier IC 31 and the control circuit IC 32 are mounted on the wiring board 34. Further, the wiring board 34 on which the amplifier IC 31 and the control circuit IC 32 are mounted is mounted on the mounting base 33. The thermoelectric conversion unit 12 described above is provided in the mounting base 33. The structure of the mounting base 33 will be described below.

  As shown in FIG. 3, the mounting base 33 includes an inner member 331 and an outer member 332 arranged around the inner member 331. An inner member 331 formed of an electrically insulating high-temperature heat conductive material is disposed on a portion of the mounting base 33 facing the amplifier IC 31 mounted on the wiring board 34. Further, the inner member 331 extends one-dimensionally in a direction substantially perpendicular to the mounting surface 33 a of the mounting table 33 in contact with the wiring board 34 inside the mounting table 33.

  For the inner member 331, for example, a carbon composite material may be used. The inner member 331 may be formed by a combination of a plurality of members. For example, a metal material having a large thermal conductivity may be disposed in the central portion of the inner member 331, and an insulating thin material may be provided on the surface portion of the metal material in contact with the electrode 123 described later.

  The external member 332 is positioned around the inner member 331 not facing the amplifier IC 31 and extends along the extending direction of the inner member 331. The material of the external material 332 is not particularly limited. However, as will be described later, the inner member 331 is used as a high heat source for thermoelectric conversion by the thermoelectric converter 12, and the outer member 332 is used as a low heat source for thermoelectric conversion. Therefore, in order to increase the temperature gradient between the inner member 331 and the outer member 332, the outer member 332 is preferably formed of a material having a lower thermal conductivity than the inner member 331.

  In FIG. 3, the thermoelectric conversion unit 12 includes a plurality of p-type thermoelectric elements 121 and n-type thermoelectric elements 122, and a plurality of electrodes 123 that connect the plurality of thermoelectric elements 121 and 122 so as to be electrically in series. 124, a ground electrode 125, and an extraction electrode 126 for the control voltage Vc. For the p-type thermoelectric element 121 and the n-type thermoelectric element 122, a known thermoelectric material such as a BiTe material, BiSb material, SbTe material, or ZnSb material may be arbitrarily selected and used.

  The plurality of p-type thermoelectric elements 121 and n-type thermoelectric elements 122 are alternately arranged in a region between the inner member 331 and the outer member 332 along the extending direction of the inner member 331 serving as a heat flow path from the amplifier IC31. ing. The inner member 331 and the p-type thermoelectric element 121 and the n-type thermoelectric element 122 are thermally connected via the electrode 123. Further, the outer member 332 and the p-type thermoelectric element 121 and the n-type thermoelectric element 122 are thermally connected via the electrode 124. Further, in FIG. 3, the thermoelectric element arranged on the right side of the inner member 331 and the thermoelectric element arranged on the left side are electrically connected by wiring 127.

  In addition, the area | region between the inner member 331 and the outer member 332 in which the p-type thermoelectric element 121 and the n-type thermoelectric element 122 are arrange | positioned should just be electrically insulated. That is, the insulating material may be disposed in the region between them, or may be hollow.

  FIG. 4 is a conceptual diagram showing how heat generated by the amplifier IC 31 shown in FIG. 3 is transmitted through the mounting base 33. As described above, the highly thermally conductive inner member 331 is disposed at a position facing the amplifier IC 31 with the wiring board 34 interposed therebetween. For this reason, the heat generated by the amplifier IC31 propagates through the inner member 331 using the inner member 331 as a main flow path. A white arrow in FIG. 4 indicates a main propagation direction of heat generated by the amplifier IC31. As a result, the temperature of the inner member 331 rises compared to the outer member 332, and a large temperature gradient is generated between the point PA on the surface of the inner member 331 and the point PB on the surface of the outer member 332.

  In order to promote heat conduction from the amplifier IC 31 to the inner member 331, a through-through hole (thermal via) 341 may be provided in the wiring board 34 as shown in FIGS.

  As shown in FIG. 3, a plurality of p-type thermoelectric elements 121 and n-type thermoelectric elements 122 are arranged along the extending direction of the inner member 331 and the outer member 332 (that is, the vertical direction in FIG. 3). Therefore, a large thermoelectromotive force due to the Seebeck effect can be obtained. For example, when a BiTe material is used for the p-type thermoelectric element 121 and the n-type thermoelectric element 122, an electromotive force of about 0.2 mV / ° C. is generated per pair of thermoelectric elements. Therefore, for example, when 1000 pairs of thermoelectric elements are arranged in the mounting base 33 by connecting the p-type thermoelectric element 121 and the n-type thermoelectric element 122 in series, an electromotive force of about 0.2 V / ° C. is obtained. This value is a sufficiently large value for controlling the gate voltage of the FET 131 in the bias circuit 13.

  As described above, according to the specific configuration of the mounting base 33 and the thermoelectric conversion unit 12 shown in FIG. 3, the self-heating of the amplifier IC 31 (that is, the amplifier 11) is caused along the extending direction of the inner member 331. It can propagate efficiently in a one-dimensional direction. Further, a large thermoelectromotive force can be obtained by the plurality of thermoelectric elements 121 and 122 arranged along the extending direction of the inner member 331.

  The amplifying apparatus 1 according to the present embodiment is particularly effective when an element having a high power density and a large calorific value, such as a GaN-FET, is used for the amplifier 11. However, it goes without saying that the amplifying element used in the amplifier 11 may be another compound semiconductor or Si-based semiconductor.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention described above.

1 is a circuit block diagram of an amplifying device according to an embodiment of the present invention. It is a circuit diagram which shows the structural example of the amplifier and bias circuit which the amplification apparatus concerning embodiment of this invention has. It is side surface sectional drawing which shows the structure of the amplifier concerning Embodiment of this invention. It is a conceptual diagram which shows the mode of the heat conduction in the amplification apparatus concerning embodiment of this invention. It is a graph which shows the distortion compensation characteristic of the amplifier concerning Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Amplifier 11 Amplifier 12 Thermoelectric conversion part 13 Bias circuit 111 FET
112 Input matching circuit 113 Output matching circuit 121 FET
Vc Control voltage VG Gate power supply voltage Vg Gate bias voltage Vd Drain power supply voltage C1 to C5 Capacitor RG Gate bias resistor LG Inductor 31 Amplifier IC
32 Control circuit IC
33 mounting base 33a mounting surface 34 wiring board 121 n-type thermoelectric element 122 p-type thermoelectric elements 123 to 126 electrode 127 wiring 331 inner member 332 external material 341 thermal via

Claims (7)

An amplifier having a first field effect transistor as an amplifying element;
A thermoelectric conversion unit that generates a voltage signal by thermoelectric conversion using a temperature gradient generated by self-heating of the amplifier;
A bias circuit that inputs the voltage signal and increases or decreases a gate bias voltage applied to the first field effect transistor according to the magnitude of the voltage signal;
Equipped with a,
The bias circuit is a variable resistance circuit that is electrically connected between a gate of the first field effect transistor and a power supply voltage, and whose resistance value changes in accordance with a feedback voltage from the output of the amplifier and the voltage signal. Comprising
Amplification equipment. An amplifier having a first field effect transistor as an amplifying element;
A thermoelectric conversion unit that generates a voltage signal by thermoelectric conversion using a temperature gradient generated by self-heating of the amplifier;
A bias circuit that inputs the voltage signal and increases or decreases a gate bias voltage applied to the first field effect transistor according to the magnitude of the voltage signal;
Mounting base;
With
The mounting table is
A mounting surface on which the amplifier is mounted;
A first portion facing the amplifier and extending one-dimensionally in a direction substantially perpendicular to the mounting surface;
A second portion located around the first portion and extending along an extending direction of the first portion, and having a lower thermal conductivity than the first portion;
With
The thermoelectric converter has a plurality of thermoelectric elements arranged along the extending direction between the first part and the second part.
Amplification equipment . The plurality of thermoelectric elements includes a plurality of p-type thermoelectric elements and n-type thermoelectric elements,
The plurality of p-type thermoelectric elements and n-type thermoelectric elements are alternately arranged between the first portion and the second portion, and the plurality of p-type thermoelectric elements and n-type thermoelectric elements are electrically The amplifying apparatus according to claim 2 , wherein the amplifying apparatus is connected in series with the amplifier. The amplification device according to claim 2 or 3 , wherein the first portion is formed of a carbon composite material having electrical insulation. The bias circuit is a variable resistance circuit that is electrically connected between a gate of the first field effect transistor and a power supply voltage, and whose resistance value changes in accordance with a feedback voltage from the output of the amplifier and the voltage signal. The amplification device according to claim 2, comprising: An amplifier having a first field effect transistor as an amplifying element;
A thermoelectric conversion unit that generates a voltage signal by thermoelectric conversion using a temperature gradient generated by self-heating of the amplifier;
A bias circuit that inputs the voltage signal and increases or decreases a gate bias voltage applied to the first field effect transistor according to the magnitude of the voltage signal;
With
The bias circuit includes a variable resistance circuit that is electrically connected between a gate of the first field effect transistor and a power supply voltage, and whose resistance value changes according to the magnitude of the voltage signal as a control voltage. ,
The variable resistance circuit includes a second field effect transistor, and one of the source and drain of the second field effect transistor is electrically connected to the gate of the first field effect transistor, and the other is electrically connected to the power supply voltage. Connected,
The voltage signal is supplied to a gate of the second field effect transistor;
Amplification equipment . A mounting surface on which an amplifier having a field effect transistor as an amplifying element is mounted;
A first portion facing the amplifier and extending one-dimensionally in a direction substantially perpendicular to the mounting surface;
A second portion located around the first portion and extending along an extending direction of the first portion, and having a lower thermal conductivity than the first portion;
A plurality of thermoelectric elements arranged along the extending direction between the first part and the second part;
Equipped with a,
A voltage signal based on a thermoelectromotive force generated by the plurality of thermoelectric elements is supplied to a bias circuit as a control voltage for adjusting a gate bias voltage applied to the field effect transistor.
Mounting base.

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