KR101690431B1 - Amplifier with active balun - Google Patents

Abstract

The present invention relates to an amplifier equipped with an active balun.
An amplifier including an active balun according to the present invention includes a first transistor formed on an integrated circuit and performing an operation through a power supply voltage, the first transistor having an ac input signal applied thereto through a gate, a first transistor A first transistor having a first terminal connected to a first terminal of the first transistor and a first terminal connected to a first terminal of the first transistor and a second terminal connected to a gate of the first transistor, A third transistor connected to the second power source and the power amplification stage, and a first stage connected to the second stage of the second transistor, a second stage connected to the second power source and the power amplifier stage, And a gate connected to the gate.
According to the present invention, when a single-ended input signal is applied in a high-frequency amplifier having a differential structure, a single-ended input signal can be amplified using a transistor and a differential signal can be generated from the input signal.

Description

[0001] AMPLIFIER WITH ACTIVE BALUN [0002]

The present invention relates to an amplifier having an active balun, and more particularly, to an amplifier having an active balun. More particularly, when a single-ended type input signal is applied to a high-frequency amplifier having a differential structure, an input signal is amplified using a transistor, To an amplifier having an active balun for generating a signal.

1 is a view for explaining the use of an amplifier according to the prior art. As shown in FIG. 1, the amplifier 130 receives an input signal from the modulator 110, amplifies the amplified signal, and outputs the amplified signal through the output node 140. At this time, it is general that the input node 120 and the output node 140 of the amplifier 101 are composed of signals of a single-ended type. However, the internal operation of the amplifier 130 is often formed in a differential structure because of the advantage of high noise immunity. In particular, when the transistor of the amplifier 130 is a MOSFET, since a virtual ground node can be formed through a differential structure, a differential structure is generally adopted in an amplifier 130 composed of a MOSFET.

In the case where the internal operation of the amplifier 130 is formed by a differential structure, an input balun for converting a single-ended input signal into a differential signal is required. Output balun that can convert a differential signal back into a single-ended signal.

2 is an internal configuration diagram of an amplifier according to the related art. As shown in FIG. 2, the input and output signals are a single-ended signal, and the amplifier 130 formed in a differential structure includes a driving amplification stage 132 and a power amplification stage 134, The output balun 135 converts the differential signal output from the power amplifying stage 134 into a single-ended signal and outputs the single-ended signal. And outputs it to the node 140.

3 is an equivalent circuit diagram of Fig. In FIG. 3, the input balun 131 and the driving amplifier stage 132 are shown in detail. The power amplifier stage 134 is shown as a block for the sake of simplicity of explanation, and the circuits after the power amplifier stage 134 are omitted. In the amplifier 130, various transistors such as a BJT, a MOSFET, a pHEMT, an HBT, and a MESFET may be used. However, the structure of the amplifier 130 is illustrated using a MOSFET as a typical transistor. 3, when a single-ended signal is input from the input node 120, the input balun 131 converts the input signal to a differential signal and transmits the differential signal to the gate of the MOSFET by M _CS1 and M _CS2 . At this time, the two signals transmitted to the gates of M _CS1 and M _CS2 are differential signals whose phases are opposite to each other and whose magnitudes are the same. V _CS is M _CS1 and an M _CS1 and the gate bias voltage of the M _CS2 for allowing M _CS2 can perform a smooth signal amplification, V _DD is for the entire amplifier 130 to carry out the operation as the amplifier 130 Power supply voltage. 3 illustrates an example of a cascode structure. The cascode structure reduces the voltage drop applied to each of the transistors, improves the reliability of the amplifier 130, and improves the voltage gain. And is commonly used in the amplifier 130 structure. At this time, V _CG is the gate bias voltage of M _CG1 and M _CG2 .

The input balun 131 shown in FIGS. 2 and 3 is mainly formed in the form of a transformer. The parasitic resistance component of the metal line forming the transformer causes the input balun 131 to generate a considerable power loss, The power gain of the entire amplifier 130 is reduced.

4 is a graph showing power gain according to the prior art. In FIG. 4, it is assumed that the power loss value by the input balun 131 is L _IN . A shows the power gain curve of the amplifier 130 when there is no input balun 131 and B shows the power gain curve of the amplifier 130 when the input balun 131 is present. Considering L _IN, which is the power loss value of the input balun 131, A is changed to B,

Thus, it can be confirmed that the input balun 131 has a problem of deteriorating the gain of the entire amplifier 130. However, since the input balun 131 converts the single-ended signal inputted to the amplifier 130 into the differential signal, the amplifier 130 of the differential structure is essential .

5 shows an integrated circuit according to the prior art. 5, when the amplifier 130 is formed as an integrated circuit, the input balun 131 is also often formed inside the integrated circuit. In general, the input balun 131 formed on the integrated circuit is mainly formed in the form of a transformer. In this case, an area on the integrated circuit is further required to form the input balun 131 on the integrated circuit. The input balun 131 increases the area of the entire integrated circuit because the input balun 131 has an area larger by several times to several tens of the area of the capacitors, the resistors and the transistors, which are the other elements constituting the amplifier 130, This increases the production cost of the integrated circuit.

The technology of the background of the present invention is disclosed in Korean Patent Registration No. 10-1449690 (published on October 13, 2014).

SUMMARY OF THE INVENTION The present invention has been made to overcome the above problems, and it is an object of the present invention to provide a high-frequency amplifier having a differential structure, which amplifies an input signal using a transistor when a single- And an active balun for generating a differential signal from the signal.

According to an aspect of the present invention, there is provided an amplifier including an active balun, the amplifier including: a first transistor formed on an integrated circuit for performing an operation through a power supply voltage and receiving an AC input signal through a gate, A second transistor having a first end connected to a first end of the first transistor and a first end connected to a first end of the first transistor and a first end of the first transistor, And a second stage connected to the second power source and the power amplifying stage and a third stage connected to the second stage of the second transistor and a second stage connected to the second power source and the power amplifier stage, And a fourth transistor having a gate connected to the gate of the third transistor.

The first transistor may further include a first capacitor connected to the gate of the first transistor, a second end of the first transistor, and a second capacitor connected between the gates of the second transistor.

A first bias voltage is applied to the gate of the first transistor, a second bias voltage is applied to the gates of the third transistor and the fourth transistor, and a third bias voltage is applied to the gate of the second transistor .

Also, the signal output to the power amplification stage may be an amplified signal having the same phase as the input signal, and an amplified signal having a phase opposite to that of the input signal.

Also, the transistor may be a MOSFET.

According to another aspect of the present invention, there is provided an amplifier including an active balun, the amplifier being formed on an integrated circuit, performing an operation through a power supply voltage, performing an operation through a power supply voltage formed on an integrated circuit, A first transistor having a first terminal connected to a first power source and a second terminal connected to a second terminal of the first transistor and having a first terminal connected to a second power source, A third transistor having a first end connected to a second end of the first transistor, a second end connected to a third power source and a power amplifier, a fourth transistor having a fourth power source and a gate connected, A fourth transistor having a first end coupled to the first power source and a second end coupled to the third power source and the power amplification stage, a first end connected to the first end of the second transistor and the second power source, The second stage of the second transistor And a second end connected to the third power source and the power amplifier stage, and a gate connected to the gate of the fourth transistor, And a sixth transistor connected in series.

The amplifier including the active balun according to the present invention amplifies a single-ended input signal using a transistor when a single-ended input signal is applied to a high-frequency amplifier having a differential structure, Can be generated.

The present invention also provides an active balun that performs the role of an input balun in a driving amplifier stage using a transistor, thereby eliminating power loss due to input baluns, thereby improving gain and power conversion efficiency of the entire amplifier, It is possible to reduce the production cost.

1 is a view for explaining the use of an amplifier according to the prior art.
2 is an internal configuration diagram of an amplifier according to the related art.
3 is an equivalent circuit diagram of Fig.
4 is a graph showing power gain according to the prior art.
5 shows an integrated circuit according to the prior art.
6 is an internal configuration diagram of an amplifier including an active balun according to the first embodiment of the present invention.
7 is an equivalent circuit diagram of Fig.
8 is a circuit diagram showing a structure of an amplifier including an active balun according to a second embodiment of the present invention.
9 is a graph comparing the power gains when the active balun and the passive balun are used.
10 is a circuit diagram showing a structure of an amplifier including an active balun according to a third embodiment of the present invention.
11 is a circuit diagram showing the structure of an amplifier including an active balun according to a fourth embodiment of the present invention.
12 is a circuit diagram showing a structure of an amplifier including an active balun according to a fifth embodiment of the present invention.

Hereinafter, an amplifier including an active balun according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

Further, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

6 and 7, an amplifier having an active balun according to an embodiment of the present invention will be described.

6 is an internal configuration diagram of an amplifier including an active balun according to the first embodiment of the present invention.

As shown in FIG. 6, the amplifier 130 including the active balun according to the embodiment of the present invention includes an active balun 133, a power amplifying stage 134, and an output balun 135.

The active balun 133 according to the present invention is a combination of the functions of the input balun 131 and the driving amplifier 132 for converting a single-ended signal input from the input node 120 into a differential signal, And is operated on the power supply voltage. The output balun 135 converts the differential signal output from the power amplifier stage 134 into a single-ended signal and outputs the signal to the output node 140.

7 is an equivalent circuit diagram of Fig.

Hereinafter, the active balun 133 will be described in detail with reference to FIG. In FIG. 7, the power amplifier stage 134 is processed as a block for convenience of explanation, and the circuits after the power amplifier stage 134 are omitted.

Since the first and second transistors M _AS and M _ACT and the third and fourth transistors M _AG1 and M _{AG2 in} FIG. 7 form a common-source short-circuit structure, The amplified signal is output in phase with the signal applied to the gate, and the current flows from the source to the drain.

First, an input signal of an AC type (Single-Ended type) is applied from an input node 120 through a gate of a first transistor M _AS , and a source is connected to a first power source (M _ACT ), and the drain thereof is connected to the gate of the second transistor M _ACT and the source of the third transistor M _AG1 .

At this time, the first transistor M _AS amplifies the input signal applied through the gate, outputs a signal having a phase opposite to that of the input signal through the drain, and applies the output signal to the second transistor M _ACT .

The first transistor M _AS has a gate connected to the first capacitor C ₁ which is a DC blocking capacitor and the first transistor M _AS can smoothly perform signal amplification through the gate thereof. A first bias voltage V _CS may be applied.

A second transistor (M _ACT) is a gate connected to the drain of the first transistor (M _AS), and the source is connected to the first transistor source and the first power supply (ground power supply) of the (M _AS), the drain 4 And is connected to the source of the transistor M _AG2 .

At this time, the first through the second transistor (M _ACT) is when the first transistor the input signal and the phase opposite to the signal from the (M _AS) through the gate is applied, a second transistor (M _ACT) is a drain, and amplifies the applied signal Outputs a signal whose phase is opposite to that of the applied signal, and applies the output signal to the fourth transistor M _AG2 .

8 is a circuit diagram showing a structure of an amplifier including an active balun according to a second embodiment of the present invention.

8, a second capacitor C ₂ , which is a DC blocking capacitor, is connected between the drain of the first transistor M _AS and the gate of the second transistor M _ACT , A third bias voltage V _{CS_1} independent of the drain voltage of the transistor MAS may be further applied to the gate.

The third transistor M _AG1 has a gate connected to the gate of the fourth transistor M _AG2 , a source connected to the drain of the first transistor M _AS , a drain connected to the second power supply V _DD , (134).

At this time, the third transistor M _AG1 has a phase opposite to that of the input signal through the drain, and the amplified signal is output and finally applied to the power amplifier stage 134.

The fourth transistor M _AG2 has a gate connected to the gate of the third transistor M _AG1 , a source connected to the drain of the second transistor M _ACT , a drain connected to the second power supply V _DD , (134).

At this time, the fourth transistor M _AG2 has the same phase as the input signal through the drain, and the amplified signal is output and finally applied to the power amplifier stage 134.

Also, a second bias voltage V _CG may be applied to the gates of the third transistor M _AG1 and the fourth transistor M _AG2 .

In summary, a signal output through the drain of the first transistor M _AS is used as an input signal to the gate of the second transistor M _ACT . As a result, the first transistor M _AS and the second transistor M _ACT are formed in opposite phases and the signals output through the drains of the first transistor M _AS and the second transistor M _ACT are also formed in opposite phases to generate a differential signal internally So that the operation of the entire amplifier 130 is formed in a differential structure.

Since the magnitudes of signals output through the drains of the first transistor M _AS and the second transistor M _ACT may not be equal to each other, the first bias voltage V _CS and the second bias voltage V _SC The magnitude of the signal output through the drains of the first transistor _MAS and the second transistor M _ACT may be adjusted by adjusting the voltage V _CG .

9 is a graph comparing the power gains when the active balun and the passive balun are used.

9, graph a shows the power gain output when the input balun 131 and the driving amplifier stage 132 according to the prior art are used, and graph b shows the power gain when the active balun 133 according to the present invention is used. A graph c shows the final power gain after the power amplifier stage 134 according to the prior art and a graph d shows the final power gain after the power amplifier stage 134 according to the present invention.

As a result of comparing the graphs a and b in FIG. 9, it can be confirmed that graph b shows a power gain synergy effect of about 3dB or more as compared to graph a with respect to input power.

Also, when the same power amplifier stage 154 is used, it can be seen that the graph d shows a power gain increase effect of about 4 dB or more as compared with the graph c.

9, the 180-nm RFCMOS process model is used. When the process model used is changed or the power supply voltage is changed, the specific result value may be changed. However, the active balun 133 ) Compared to the case where the input balun 131 according to the prior art is used, the tendency that the power gain rises remains unchanged.

10 is a circuit diagram showing a structure of an amplifier including an active balun according to a third embodiment of the present invention.

10, an input signal of an AC type (Single-Ended type) is applied from an input node 120 through a gate of the first transistor M _AS , a source is connected to a first power source And the drain thereof is connected to the gate of the second transistor M _ACT and the source of the third transistor M _AG1 .

At this time, the first transistor M _AS amplifies an input signal applied through the gate, outputs a signal having a phase opposite to that of the input signal through the drain, and outputs the output signal to the second transistor M _ACT and the third transistor M _AG1 .

The first transistor M _AS has a gate connected to the first capacitor C ₁ which is a DC blocking capacitor and the first transistor M _AS can smoothly perform signal amplification through the gate thereof. A first bias voltage V _CS may be applied.

A second transistor (M _ACT) is a gate connected to the drain of the first transistor (M _AS), and the source is connected to the fifth transistor source and the second power supply (ground power supply) of the (M _{AS _ 1),} the drain And connected to the source of the fourth transistor M _AG2 .

At this time, the first through the second transistor (M _ACT) is when the first transistor the input signal and the phase opposite to the signal from the (M _AS) through the gate is applied, a second transistor (M _ACT) is a drain, and amplifies the applied signal Outputs a signal whose phase is opposite to that of the applied signal, and applies the output signal to the fourth transistor M _AG2 .

11 is a circuit diagram showing the structure of an amplifier including an active balun according to a fourth embodiment of the present invention.

11, a second capacitor C ₂ , which is a DC blocking capacitor, is connected between the drain of the first transistor M _AS and the gate of the second transistor M _ACT , A third bias voltage V _{CS_1} independent of the drain voltage of the transistor MAS may be further applied to the gate of the second transistor M _ACT .

The third transistor M _AG1 has a gate connected to the fourth power supply (ground power supply), a source connected to the drain of the first transistor M _AS , a drain connected to the third power supply VDD and the power amplifier 134, Lt; / RTI >

At this time, the third transistor (M _AG1) is the fourth capacitors a DC blocking capacitor (DC-Blocking) to the gate (C ₄₎ is connected and the third transistor through a gate (M _AG1) is allowed to perform a smooth signal amplification A fourth bias voltage V _{CG_ 1} may be applied to the second _{transistor Q 1} .

Also, the third transistor M _AG1 is opposite in phase to the input signal through the drain, and the amplified signal is output and finally applied to the power amplifier stage 134.

The fourth transistor M _AG2 has a gate connected to the gate of the sixth transistor M _{AG1 _ 1} , a source connected to the drain of the second transistor M _ACT , a drain connected to the third power source V _DD , And is connected to the power amplifier stage 134.

At this time, the fourth transistor M _AG2 has the same phase as the input signal through the drain, and the amplified signal is output and finally applied to the power amplifier stage 134.

A fifth transistor (M _{AS _ 1)} is a gate, the second transistor being coupled to the drain of the (M _ACT), said source is coupled to the second transistor source and the second power supply (ground power supply) of the (M _ACT), a drain And is connected to the source of the sixth transistor M _{AG1_1} .

11, a third capacitor C ₃ , which is a DC blocking capacitor, is connected between the drain of the second transistor M _ACT and the gate of the fifth transistor M _{AS_1} , A fifth bias voltage V _{CS_2} independent of the drain voltage of the transistor M _ACT may be further applied to the gate of the fifth transistor M _{AS_1} .

A sixth transistor (M _{AG1 _ 1)} is a gate 4 is connected to the transistor (M _AG2), and the source is coupled to the drain of the fifth transistor (M _{AS _ 1),} drain the third power source (VDD) and the power And is connected to the amplification stage 134.

At this time, the signal output through the drain of the sixth transistor M _{AG1 _ 1} is combined with the signal output from the third transistor M _AG1 , and the amplified signal having the opposite phase to the input signal is applied to the power amplifier stage 134 .

Also, a second bias voltage V _CG may be applied to the gates of the fourth transistor M _AG2 and the sixth transistor M _{AG1 _ 1} .

12 is a circuit diagram showing a structure of an amplifier including an active balun according to a fifth embodiment of the present invention.

As shown in Figure 12, the third transistor may be a fourth bias voltage (V _{CG _ 1)} the second bias voltage (V _CG), instead of being applied to the gate of the (M _AG1) is applied.

This has the advantage of reducing the autonomy of the circuit voltage regulation aspects, but reducing the number of required bias circuits.

In addition, the third and fifth embodiments are the same as the fifth and sixth transistors M _{AS_1} and M _{AG1 _ 1 in} the first and second embodiments. Accordingly, the operation of the first to fourth transistors M _AS , M _ACT , M _AG1 and M _AG2 is the same as that described above, and the fifth transistor M _{AS _ 1} is connected to the drain of the second transistor M _ACT It receives the signal output to the gate there is carried out an operation as an amplifier, wherein the first transistor (M _aS) and the fifth transistor and the signal phase with each other to be output through the drains of the (M _{aS _ 1),} the first transistor A differential signal is formed between the signal output through the drain of the first transistor M _AS and the drain of the fifth transistor M _{AS_1} and the signal output through the drain of the second transistor M _ACT .

Therefore, the third transistor (M _AG1) and the sixth transistor (M _{AG1 _ 1)} and the third transistor (M _AG1), such as signal also because together statue from 10 to 12 is output via the drain of the sixth transistor (M _{AG1 _ 1} ) may be formed by connecting one node to another.

In the present invention, the case where the transistor is a MOSFET is described as an example. However, when the transistor is composed of a transistor such as a BJT and an HBT, a pHEMT and an MESFET may be applied instead of a MOSFET. The collector may be configured to correspond to the gate, source, and drain of the MOSFET, respectively.

As described above, the amplifier including the active balun according to the embodiment of the present invention amplifies a single-ended type input signal using a transistor when a single-ended type input signal is applied in a high- And simultaneously generate a differential signal from the input signal.

In addition, by using the transistor to form an active balun that performs the role of the input balun in the driving amplifier stage, power loss due to the input balun is eliminated, thereby improving the gain and power conversion efficiency of the entire amplifier, There is an effect that the production unit cost can be reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined by the appended claims. will be. Accordingly, the true scope of the present invention should be determined by the following claims.

110: modulator 120: input node
130: Amplifier 131: Input balun
132: driving amplifier stage 133: active balun
134: power amplifier stage 135: output balun
140: Output node

Claims (8)

delete delete delete 1. An amplifier having an active balun formed on an integrated circuit and performing an operation through a power supply voltage,
A first transistor to which an input signal of an alternating current type is applied through a gate and whose first end is connected to a first power supply,
A second transistor having a second terminal coupled to a gate of the first transistor and a first terminal coupled to a second power supply,
A third transistor having a first end connected to a second end of the first transistor, a second end connected to a third power source and a power amplification stage,
A fourth transistor having a first terminal connected to the second terminal of the second transistor and a second terminal connected to the third power source and the power amplifying terminal,
A fifth transistor having a first end coupled to a first end of the second transistor and the second power supply and a gate coupled to a second end of the second transistor,
And a sixth transistor having a first terminal connected to the second terminal of the fifth transistor, a second terminal connected to the third power source and the power amplifying terminal, and a gate connected to a gate of the fourth transistor, An amplifier with a balun. 5. The method of claim 4,
A first capacitor coupled to a gate of the first transistor,
A second capacitor coupled between a second end of the first transistor and a gate of the second transistor,
A third capacitor coupled between the second end of the second transistor and the gate of the fifth transistor,
And a fourth capacitor coupled to the gate of the third transistor. 5. The method of claim 4,
A first bias voltage is applied to the gate of the first transistor, a second bias voltage is applied to the gates of the fourth transistor and the sixth transistor, a third bias voltage is applied to the gate of the second transistor, An active balun having a fourth bias voltage applied to the gate of the third transistor and a fifth bias voltage applied to the gate of the fifth transistor. 5. The method of claim 4,
Wherein the signal output to the power amplification stage has the same phase as the input signal and has an amplified signal and an active balun that is an amplified signal that is opposite in phase to the input signal. 5. The method of claim 4,
Wherein the transistor is a MOSFET.

Images