KR101212633B1 - Combiner using transmission line transformer - Google Patents

Abstract

PURPOSE: A combiner using a transmission line transformer is provided to reduce production costs of a transmitting terminal by comprising the combiner using the transmission line transformer in a wireless communication system. CONSTITUTION: A combiner using a transmission line transformer comprises first and second differential amplifiers(11,12), a transmission line transformer(20), and a matching unit(30). The first and the second differential amplifiers differentially amplify an input signal. The transmission line transformer comprises a first primary transmission line(21), a second primary transmission line(23), a second secondary transmission line(24), and a first secondary transmission line(22). The matching unit matches input impedances by connecting first resistance(31) to second resistance(32) between differential signal paths of a first differential amplifier and a second differential amplifier.

Description

Combiner using transmission line transformer {COMBINER USING TRANSMISSION LINE TRANSFORMER}

The present invention relates to a coupler using a transmission line transformer, and more particularly, to a coupler using a transmission line transformer, which allows a linear outpage operation while reducing the area by configuring the coupler using a transmission line transformer in a wireless communication system. .

As the wireless communication protocol evolves, the linearity and efficiency characteristics of the transmitter are required to be higher and higher, and various structures other than the general linear power amplifier are proposed and actively studied. .

Among these structures, the LIN (Liar amplification with Nonlinear Components) structure is based on the use of efficient switching power amplifiers, and outphasing the phases of the signals applied to the two amplifiers. By adjusting the size of the structure, good linearity and efficiency characteristics can be obtained.

라고 하면 신호의 크기에 해당하는 a(t) 성분을 위상 차로 변환하고 일정한 신호크기를 가지는 두 개의 신호

와

의 합으로 x(t)를 표현 할 수 있다. (이때,

이다.)This can be expressed as follows. Input signal to be amplified

In this case, two signals having a constant signal size are converted by converting a (t) component corresponding to the magnitude of the signal into a phase difference.

Wow

We can express x (t) by the sum of. (At this time,

to be.)

When these input signals are amplified and combined, the phase difference components of the output signal are determined by the vector sum, and thus an output signal having the same result as the original signal amplified can be obtained.

In this LINC architecture, a coupler that linearly combines the outpaged output power is a necessary element.

Background art of the present invention is disclosed in Republic of Korea Patent Publication No. 10-2007-0101723 (2007.01.17.).

A commonly used combiner for combining such outpaged output power is a Wilkinson power combiner.

The Wilkinson power combiner combines the signals applied to the two input ports, and linear output characteristics by dissipating the magnitude of the signal applied to the two ports as heat from the resistance connected between the two ports. Can be obtained.

However, this characteristic can be obtained by combining each of the λ / 4 transmission lines according to the wavelength of the frequency used when connecting the two ports, so that these transmission line lengths in the several GHz band mainly used for portable wireless communication In order to secure a large area is required, there is a problem that is very disadvantageous to the integration of the circuit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a coupler using a transmission line transformer that allows linear outpage operation while reducing the area by configuring a coupler using a transmission line transformer in a wireless communication system. There is a purpose.

Coupler using a transmission line transformer according to an aspect of the present invention comprises a first to second differential amplifier for differentially amplifying the input signal and outputs; A transmission line transformer for coupling the differential signal of the first to second differential amplifiers through a transmission line and outputting the combined signal; And a matching unit connected between the differential signal paths of the first to second differential amplifiers to match the input impedance and dissipate the output when the input signal is outpaged.

In the present invention, the transmission line transformer comprises: a first primary side transmission line connecting both ends of the differential signal of the first differential amplifier; A second primary side transmission line connecting both ends of the differential signal of the second differential amplifier; And a first secondary side transmission line corresponding to the first primary side transmission line and a second secondary side transmission line respectively corresponding to the second primary side transmission line are connected in series, one side of the second secondary side transmission line is grounded, and the first secondary side transmission line is grounded. The other side of the output terminal is characterized in that coupled to the differential signal output.

In accordance with another aspect of the present invention, a combiner using a transmission line transformer includes: first to second differential amplifiers for differentially amplifying and outputting an input signal; A transmission line transformer for coupling the differential signal of the first to second differential amplifiers through a transmission line and outputting the combined signal; And a matching unit having a matching transmission line and a resistor corresponding to the transmission line of the transmission line transformer, matching the input impedance, and dissipating the output when the input signal is outpaged.

In the present invention, the transmission line transformer comprises: a first primary side transmission line connecting both ends of the differential signal of the first differential amplifier; A second primary side transmission line connecting both ends of the differential signal of the second differential amplifier; And a first secondary side transmission line corresponding to the first primary side transmission line and a second secondary side transmission line respectively corresponding to the second primary side transmission line are connected in series, one side of the second secondary side transmission line is grounded, and the first secondary side transmission line is grounded. The other side of the output terminal is characterized in that coupled to the differential signal output.

In accordance with still another aspect of the present invention, a combiner using a transmission line transformer includes: first to second linear amplifiers for linearly amplifying and outputting an input signal; A transmission line transformer for combining and outputting an amplified signal of the first to second linear amplifiers through a transmission line; And a matching unit having a matching transmission line and a resistor corresponding to the transmission line of the transmission line transformer, matching the input impedance, and dissipating the output when the input signal is outpaged.

In the present invention, the transmission line transformer is connected to the first primary side transmission line and the second primary side transmission line through an amplified signal of the first to second linear amplifiers, and the first secondary side transmission line and the second secondary line corresponding to the first primary side transmission line. A second secondary transmission line corresponding to the primary transmission line is connected in series with each other, one side of the second secondary transmission line is grounded, and the other side of the first secondary transmission line is connected to an output terminal, thereby combining and outputting an amplified signal; do.

In the present invention, the matching unit includes a first matching transmission line that is interposed between the first primary side transmission line and the first secondary side transmission line and a second matching transmission line that is interposed between the second primary side transmission line and the second secondary side transmission line. A resistance is mediated between the other side of the matching transmission line and ground, one side of the first matching transmission line and one side of the second matching transmission line are connected, and the other side of the second matching transmission line is connected to ground.

In the present invention, the matching unit is characterized in that both ends of the first to second matching transmission lines arranged to correspond respectively to the first secondary side transmission line and the second secondary side transmission line are connected in parallel via the first to second resistances.

The present invention can reduce the area and reduce the size of the transmitter because it is possible to reduce the area, linear outpage operation and easy integration by configuring the combiner using a transmission line transformer in a wireless communication system.

1 is a circuit diagram and an operation of a coupler using a transmission line transformer according to an embodiment of the present invention.
2 is a characteristic graph of an outphasing operation of a combiner using a transmission line transformer according to an embodiment of the present invention.
3 is an output graph combining a power amplifier with a combiner using a transmission line transformer according to an embodiment of the present invention.
4 is a circuit diagram and an operation of a coupler using a transmission line transformer according to another exemplary embodiment of the present invention.
5 is a circuit diagram and an operation of a coupler using a transmission line transformer according to another exemplary embodiment of the present invention.
6 is a block diagram showing a coupler using a transmission line transformer according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of a coupler using a transmission line transformer according to the present invention. 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. In addition, 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.

1 is a circuit diagram and an operation of a coupler using a transmission line transformer according to an embodiment of the present invention.

As shown in FIG. 1, a coupler using a transmission line transformer according to an embodiment of the present invention includes first to second differential amplifiers 11 and 12, a transmission line transformer 20, and a matching unit 30.

The first to second differential amplifiers 11 and 12 differentially amplify an input signal and output the differential signal.

The transmission line transformer 20 and the first primary side transmission line 21 connecting both ends of the differential signal of the first differential amplifier 11 to combine and output the differential signals of the first to second differential amplifiers 11 and 12. The first secondary side transmission line 22 and the second primary side transmission line 22 corresponding to the second primary side transmission line 23 and the first primary side transmission line 21 connecting both ends of the differential signal of the second differential amplifier 12 ( 23, the second secondary side transmission line 24 corresponding to each other is connected in series, one side of the second secondary side transmission line 24 is grounded, and the other side of the first secondary side transmission line 22 is connected to the output terminal 40. do.

The matching unit 30 is connected between the first resistor 31 and the second resistor 32 between the differential signal paths of the first differential amplifier 11 and the second differential amplifier 12 so as to match the input impedance and input the input impedance. When the signal is outpaged, the output is destroyed.

In this case, a capacitor or an inductor may be used in addition to the first resistor 31 to the second resistor 32.

In addition, it is preferable that the impedance value of the matching part has a value twice the internal impedance Zin facing the transmission line transformer 20 as shown in FIG. 1.

The operation of the coupler using the transmission line transformer configured as described above will be described.

First, as shown in (a) of FIG. 1, when the input signals inputted to the first differential amplifier 11 and the second differential amplifier 12 have the same phase, the differential signals of the two input signals are transmitted to the transmission line transformer 20. Are transmitted to the first to second primary side transmission lines 21 and 13, respectively, and the output voltage is coupled to the output terminal 40.

At this time, since the voltage across the first to second resistors 31 and 32 of the matching unit 30 connected between the differential signal paths of the first to second differential amplifiers 11 and 12 is the same, the first to second resistors are the same. There is no current flowing through (31, 32).

However, as shown in (b) of FIG. 1, when the input signals of the first to second differential amplifiers 11 and 12 are opposite to each other (180 degrees apart), the signals coming through the respective differential paths are transmitted to the transmission line transformer 20. Voltages transmitted to the first to second secondary side transmission lines 22 and 24 of N are canceled with each other so that no power is output.

On the other hand, due to the voltage across the first to second resistors 31 and 32 connected between the differential paths, a virtual ground is formed in the center of the resistor and the first to second differential amplifiers 11 and 12 are formed. ), The differential signal flows through the first to second resistors 31 and 32 and is consumed as heat.

This operation is similar to that of the Wilkinson coupler, implemented through a resistance value determined by twice the input impedance, and made to appear constant input impedance regardless of the phase difference of the input signals of the first to second differential amplifiers 11 and 12. do.

Such a coupler may be applied when designing a semiconductor integrated circuit or a printed circuit board (PCB).

2 is a characteristic graph of an outphasing operation of a combiner using a transmission line transformer according to an embodiment of the present invention.

2 are graphs showing computer simulation results of a coupler using a transmission line transformer according to an exemplary embodiment of the present invention, and the input power of each differential path of the first to second differential amplifiers 11 and 12 is 10 dBm. It can be seen from the graph (a) that the linear outphasing output characteristics are obtained from the combined four times 16 dBm.

In addition, since the outputs are matched to 50 ohms due to the four differential signal paths connected to the first to second differential amplifiers 11 and 12, the input impedance at the primary side of the transmission line transformer 20 is 12.5 ohms, resulting in an out-page output result phase difference. It can be seen from the graph (c) that a constant value can be obtained regardless.

3 is an output graph combining a power amplifier with a combiner using a transmission line transformer according to an embodiment of the present invention.

As shown in FIG. 3, when the transmission line transformer according to the exemplary embodiment of the present invention is combined with a power amplifier, the results obtained through computer simulation and measurement are confirmed, the ideal calculated value and the simulation value and the measured value are almost identical. Can be.

As described above, according to the coupler using the transmission line transformer according to the present invention, a linear outpage coupler having a small area can be made, and the transmission line transformer 20 can be used as a matching circuit of the differential amplifier, thereby simplifying the structure of the output stage. It is easy to integrate and can achieve cost reduction and miniaturization of the transmitter.

4 is a circuit diagram and an operation of a coupler using a transmission line transformer according to another exemplary embodiment of the present invention.

As shown in FIG. 4, a combiner using a transmission line transformer according to another embodiment of the present invention includes first to second differential amplifiers 11 and 12 that differentially amplify an input signal and output the first to second differential amplifiers. Transmission line transformer 20 and transmission line transformer for combining and outputting the differential signals 11 and 12 through the first to second primary side transmission lines 21 and 23 and the first to second secondary side transmission lines 22 and 24. First to second matched transmission lines 33 and 34 and resistors 35 corresponding to the first to second primary side transmission lines 21 and 23 and the first to second secondary side transmission lines 22 and 24 of (20). And a matching unit 30 matching the input impedance and extinguishing the output when the input signal is outpaged.

In this case, the transmission line transformer 20 may include a first primary side transmission line 21 connecting both ends of the differential signal of the first differential amplifier 11 and a second primary side transmission line connecting both ends of the differential signal of the second differential amplifier 12. 23 and the first secondary transmission line 22 corresponding to the first primary transmission line 21 and the second secondary transmission line 24 corresponding to the second primary transmission line 23 are connected in series with each other. One side of the second secondary transmission line 24 is grounded, and the other side of the first secondary transmission line 22 is connected to the output terminal 40.

In addition, the matching unit 30 may include a first matching transmission line 33 and a second primary transmission line 23 and a second secondary side that are interposed between the first primary side transmission line 21 and the first secondary side transmission line 22. And a second matching transmission line 34 interposed between the transmission lines 24, wherein a resistance 35 is interposed between the other side of the first matching transmission line 33 and the ground, and one side of the first matching transmission line 33. One side of the second matching transmission line 34 is connected and the other side of the second matching transmission line 34 is connected to ground.

In this case, the matching unit 30 may be configured like the matching unit 30 shown in FIG. 5.

Referring to the operation of the coupler using the transmission line transformer configured as described above are as follows.

As shown in (a) of FIG. 4, when the input signals input to the first differential amplifier 11 and the second differential amplifier 12 have the same phase, the differential signals of the two input signals are transmitted to the transmission line transformer 20. The first to second primary side transmission lines 21 and 23 are respectively transmitted, and the output voltage is coupled to the output terminal 40.

At this time, there is no current flowing to the matching unit 30.

However, as shown in (b) of FIG. 4, when the input signals of the first to second differential amplifiers 11 and 12 are outpaged in opposite directions (180 degrees apart), the signals coming out from the differential paths are transmitted to the transmission line transformer. There is no output since the first through second primary side transmission lines 21 and 23 of 20 are transferred to the first through second matching transmission lines 33 and 34 and consumed as heat through the resistor 35.

5 is a circuit diagram and an operation of a coupler using a transmission line transformer according to another exemplary embodiment of the present invention.

As shown in FIG. 5, a coupler using a transmission line transformer according to another embodiment of the present invention includes first to second linear amplifiers 13 and 14 for linearly amplifying and outputting an input signal, and first to second linear amplifiers. Transmission line transformer 20 and transmission line transformer for combining and outputting the amplified signal of (13, 14) through the first to second primary side transmission line (21, 23) and the first to second secondary side transmission line (22, 24) First to second matched transmission lines 33 and 34 and first to second corresponding to first to second primary side transmission lines 21 and 23 and first to second secondary side transmission lines 22 and 24 of (20). And a matching unit 30 having second resistors 31 and 32 to match the input impedance and to dissipate the output when the input signal is outpaged.

At this time, the transmission line transformer 20 is connected to the first primary side transmission line 21 and the second primary side transmission line 23 via an intermediate ground via the amplified signal of the first to second linear amplifiers, and the first primary side transmission line ( The second secondary side transmission line 24 corresponding to the first secondary side transmission line 22 and the second primary side transmission line 23 respectively corresponding to 21 are connected in series with each other, and one side of the second secondary side transmission line 24 is connected. The ground and the other side of the first secondary transmission line 22 are connected to the output terminal 40 to combine and output the amplified signal.

The matching unit 30 has both ends of the first to second matching transmission lines 33 and 34 disposed so as to correspond to the first secondary transmission line 22 and the second secondary transmission line 24, respectively. It is connected in parallel via (31,32).

In this case, the matching unit 30 may be configured as the matching unit 30 shown in FIG. 4.

Referring to the operation of the coupler using the transmission line transformer configured as described above are as follows.

As shown in FIG. 5A, when the amplified signals of the first to second linear amplifiers 10 have the same phase, the amplified signals are transmitted to the first to second primary side transmission lines 21 of the transmission line transformer 20. 23, respectively, and the output voltage is coupled to the output terminal 40.

At this time, there is no current flowing to the matching unit 30.

However, as illustrated in FIG. 5B, when the amplified signals of the first to second linear amplifiers 13 and 14 are outpaged in opposite directions (180 degrees apart), the amplified signals of the transmission line transformer 20 There is no output since it is transmitted to the first to second matching transmission lines 33 and 34 through the first to second primary side transmission lines 21 and 23 and consumed as heat through the first to second resistors 31 and 32. do.

6 is a block diagram showing a coupler using a transmission line transformer according to another embodiment of the present invention.

As shown in FIG. 6, a combiner using a transmission line transformer according to still another embodiment of the present invention is arranged by arranging a plurality of combiners using the transmission line transformer shown in FIG. 1 and connecting the secondary side transmission lines of the transmission line transformer to each other in series. It is configured to output the combined input signal.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. I will understand. Accordingly, the technical scope of the present invention should be defined by the following claims.

11,12: 1st to 2nd differential amplifier
13,14: first to second linear amplifier
20: transmission line transformer
21, 23: first to second primary side transmission line
22, 24: first to second secondary transmission line
30: matching part 31, 32: first to second resistance
33,34: first to second matching transmission line
35 resistance 40 output stage

Claims (8)

First to second differential amplifiers for differentially amplifying and outputting an input signal;
A transmission line transformer for coupling the differential signal of the first to second differential amplifiers through a transmission line and outputting the combined signal; And
And a matching unit connected between the differential signal paths of the first to second differential amplifiers to match an input impedance and to dissipate an output when the input signal is outpaged.
The transformer of claim 1, wherein the transmission line transformer
A first primary side transmission line connecting both ends of the differential signal of the first differential amplifier;
A second primary side transmission line connecting both ends of the differential signal of the second differential amplifier; And
The first secondary side transmission line corresponding to the first primary side transmission line and the second secondary side transmission line corresponding to the second primary side transmission line are connected in series with each other, and one side of the second secondary side transmission line is grounded, and the first A coupler using a transmission line transformer, characterized in that the other side of the secondary transmission line is connected to an output terminal to output the combined differential signal.
First to second differential amplifiers for differentially amplifying and outputting an input signal;
A transmission line transformer for coupling the differential signal of the first to second differential amplifiers through a transmission line and outputting the combined signal; And
And a matching unit including a matching transmission line and a resistor corresponding to the transmission line of the transmission line transformer to match an input impedance and dissipate an output when the input signal is outpaged.
4. The transmission line transformer of claim 3, wherein the transmission line transformer
A first primary side transmission line connecting both ends of the differential signal of the first differential amplifier;
A second primary side transmission line connecting both ends of the differential signal of the second differential amplifier; And
The first secondary side transmission line corresponding to the first primary side transmission line and the second secondary side transmission line corresponding to the second primary side transmission line are connected in series with each other, and one side of the second secondary side transmission line is grounded, and the first A coupler using a transmission line transformer, characterized in that the other side of the secondary transmission line is connected to an output terminal to output the combined differential signal.
First to second linear amplifiers for linearly amplifying and outputting the input signals;
A transmission line transformer for coupling and outputting an amplified signal of the first to second differential amplifiers through a transmission line; And
And a matching unit including a matching transmission line and a resistor corresponding to the transmission line of the transmission line transformer to match an input impedance and dissipate an output when the input signal is outpaged.
The method of claim 5, wherein the transmission line transformer
A first secondary side transmission line and a second secondary side transmission line corresponding to the first primary side transmission line and the second primary side transmission line connected to the first primary side transmission line and the second primary side transmission line through an intermediate ground of the amplified signal of the first to second linear amplifiers Second secondary transmission lines respectively corresponding to the primary transmission line are connected in series with each other, one side of the second secondary transmission line is grounded, and the other side of the first secondary transmission line is connected to an output terminal to couple and output the amplified signal. Coupler using a transmission line transformer, characterized in that.
The method of claim 4 or 6, wherein the matching portion
A transmission line transformer, characterized in that both ends of the first to second matching transmission lines arranged to correspond to the first secondary side transmission line and the second secondary side transmission line respectively include a matching unit connected in parallel to each other via first to second resistances; Combiner using.
The method of claim 4 or 6, wherein the matching portion
And a first matched transmission line interposed between the first primary side transmission line and the first secondary side transmission line and a second matched transmission line interposed between the second primary side transmission line and the second secondary side transmission line, wherein the first matched transmission line is interposed between the first primary side transmission line and the first secondary side transmission line. The transmission line transformer, characterized in that the resistance is mediated between the other side of the matching transmission line and the ground, one side of the first matching transmission line and one side of the second matching transmission line is connected and the other side of the second matching transmission line is connected to ground. Used coupler.

Images