KR20120139335A - Doherty power amplifier being insert type - Google Patents

Abstract

PURPOSE: An embedded type bias mixed power amplifier is provided to obtain maximum output power by adding an embedded peaking amplifier to a conventional Doherty amplifier structure. CONSTITUTION: An embedded peaking amplifier(201) amplifies a basic signal of an input signal while being connected to a conventional Doherty amplifier(100) in parallel. A 90° hybrid distributor(202) respectively distributes power of the input signal in a 90° phase difference to the embedded peaking amplifier and the conventional Doherty amplifier. A first offset line(203) induces an output load of the conventional Doherty amplifier to a short. A second offset line(204) induces the output load of the embedded peaking amplifier to the short. A first transformer(205) performs load modulation between the first offset line and the second offset line. A second transformer(206) changes the load. [Reference numerals] (101) Main amplifier; (102) Peaking Amplifier; (104) Third transformer; (105) Fourth transformer; (106) Third offset line; (107) Fourth offset line; (201) Embedded Peaking Amplifier; (203) First offset line; (204) Second offset line; (205) First transformer; (206) Second transformer

Description

Inserted bias mixed power amplification device {Doherty power amplifier being insert type}

The present invention relates to an embedded bias mixed power amplifier, and more particularly, by adding an embedded peaking amplifier to the conventional Doherty amplifier structure, thereby providing a P1dB reference output of the conventional Doherty amplifier. An integrated bias mixed power amplifier that enables maximum efficiency at a point lower than one 6dB backoff point, and at the point of 3dB increase from the conventional P1dB.

Currently, in a mobile communication system, a power amplifier is provided at the final output terminal of a base station (BS) and mobile stations (MS) to output a low level input signal, for example, a base band signal, at a high level. Amplifies into a signal, such as an RF band signal. At this time, the RF band signal is a distortion component of the signal when the power amplifier is non-linear, the non-linear characteristics of the power amplifier is a frequency component due to the gain degradation of the input signal and inter-modulation other than the input frequency Create Accordingly, the linearity is an important characteristic in a power amplifier because the generated frequency component affects adjacent channels and degrades the overall system performance.

Meanwhile, the power amplifier includes a single carrier power amplifier (SCPA) using a single carrier according to the bandwidth of an input signal, and a multicarrier power amplifier using a multicarrier (MCPA). Multi Carrier Power Amplifier, hereinafter referred to as 'MCPA'). Since SCPA amplifies a single carrier, i.e., 1FA signal, complicated and sophisticated linearization for ensuring linearity is unnecessary, and only needs to be back-off by Peak to Average Power Ratio (PAR) at maximum output power. Since the MCPA amplifies a 3FA signal in a multi-carrier, for example, a WiBro system, and an 8-15FA signal in a CDMA system, linearization is required to remove wideband intermodulation components.

In recent years, techniques for increasing transmission speed and capacity through beam forming, diversity, and the like by applying multiple antenna technologies to mobile communication systems have been applied. This multi-antenna technology has the advantage of lowering the output power of the power amplifier driving the individual antennas, although the total output power is the same in terms of the power amplifier because of the use of multiple antennas. When the multi-antenna technology is applied to a mobile communication system, a multi-mode power amplifier operating with MCPA has been proposed to improve the usability of the mobile communication system.

In addition, in the power amplifier, not only the linearity of the power amplifier described above but also the efficiency of the power amplifier is an important parameter. In order to improve the efficiency of such a power amplifier, a Doherty Amplifier has been proposed. Unlike a balanced amplifier, a Doherty amplifier is asymmetrical parallel coupling of a carrier amplifier and a peaking amplifier. Structure. More specifically, the Doherty amplifier, as shown in FIG. 1, is an example of a power amplifier used in a high efficiency modulation scheme in a mobile communication system, first proposed by WH Doherty in 1936, and its structure is a quarter wave transformer. (Quarter Wave Transformer) (λ / 4 transformer) connects main amplifier and peaking amplifier in parallel. In addition, the peaking amplifier may increase the efficiency of the Doherty amplifier by adjusting the load impedance of the main amplifier by varying the amount of current supplied to the load according to the power level. Can be.

On the other hand, such a conventional Doherty amplifier structure can achieve maximum efficiency at one point of 6 dB backoff at the P1dB reference output, sometimes in the defense industry, rather than at this point of 6 dB backoff. In addition, there is a demand for maximum efficiency at a lower point, and in some cases, a specification for obtaining maximum output power at a point increased by 3 dB from the existing P1dB is required.

The present invention was developed to meet the above needs, by adding an embedded peaking amplifier to the conventional Doherty amplifier structure to provide a 6 dB backoff at the P1 dB reference output of the conventional Doherty amplifier. Its purpose is to provide an embedded bias mixed power amplifier that enables maximum efficiency at a point lower than one point, and at the point of 3dB increase from the existing P1dB.

Insertion type bias mixed power amplification apparatus according to the present invention for achieving this object,

A conventional doherty amplifier, an embedded peaking amplifier connected in parallel to the conventional Doherty amplifier to amplify a basic signal of an input signal, and each of the embedded peaking amplifier and the conventional Doherty amplifier. 90 ° hybrid divider that distributes the power of the input signal with a phase difference, a first offset line that directs the output load of the conventional Doherty amplifier to short (0), and the output load of the embedded peaking amplifier to short (0) A second offset line to induce, a first transformer installed between the first offset line and the second offset line to perform a load modulation function, and connected to the second offset line and the first transformer to provide a load ( And a second transformer for converting the load).

Advantageously, the conventional doherty amplifier comprises a second 90 ° hybrid divider for distributing power of an input signal by a 90 ° phase difference to each of the main amplifier and the peaking amplifier, the main amplifier and the peaking amplifier, and the main amplifier. And a third transformer connected to each output terminal of the peaking amplifier to perform load modulation, and a fourth transformer connected to the peaking amplifier and the third transformer to convert load. do.

The present invention achieves maximum efficiency at a lower point than a conventional doherty amplifier. That is, a conventional doherty amplifier can obtain maximum efficiency at one place of 6 dB backoff at a P1 dB reference output power. However, the present invention provides a 6 dB backoff of a conventional doherty amplifier. backoff) Maximum efficiency can be achieved at a point lower than one point.

In addition, the present invention has an effect of obtaining a maximum output power at a point increased by 3 dB from the existing P1 dB by adding an embedded peaking amplifier to the conventional Doherty amplifier structure.

1 is a detailed block diagram showing an embedded bias mixed power amplifying apparatus according to the present invention.
Figure 2a is a diagram illustrating the operation of the embedded bias mixed power amplification device when the input power is a low level according to the present invention;
Figure 2b is a diagram illustrating the operation of the embedded bias mixed power amplification device made when the input power is a high level in accordance with the present invention;
3 is a graph showing the effect of the embedded bias mixed power amplifier according to the present invention;

Hereinafter, the present invention will be described with reference to the accompanying drawings.

It is to be understood, however, that the embodiments described below are only for explanation of the embodiments of the present invention so that those skilled in the art can easily carry out the invention, It does not mean anything.

In order to clearly illustrate the present invention, portions which are not related to the description have been omitted, and like reference numerals have been assigned to similar portions throughout the specification.

Throughout the specification and claims, when a section includes a constituent, it is intended that the inclusion of the other constituent (s) does not exclude other elements unless specifically stated otherwise.

1 is a detailed block diagram illustrating an embedded bias mixed power amplifier according to the present invention.

As shown in FIG. 1, the embedded bias mixed power amplifier according to the present invention further adds an embedded peaking amplifier 201 to the structure of a conventional Doherty amplifier 100. The maximum efficiency can be obtained at a point lower than 6 dB backoff point at the P1dB reference output of the National Doherty amplifier 100, and at the point of 3dB increase from the conventional P1dB, the maximum output power can be obtained. will be.

Specifically, a conventional doherty amplifier 100, an embedded peaking amplifier 201, a 90 ° hybrid divider 202, a first offset line 203, a second offset line 204, a first transformer 205, and a second transformer 206.

That is, a conventional doherty amplifier 100, an embedded peaking amplifier 201 connected in parallel to the conventional Doherty amplifier 100 and amplifying a basic signal of an input signal, the embedded The output load of the conventional Doherty amplifier 100 is shorted by a 90 ° hybrid divider 202 which distributes power of an input signal by 90 ° phase difference to each of the peaking amplifier 201 and the conventional Doherty amplifier 100. A first offset line 203 leading to zero), a second offset line 204 leading the output load of the embedded peaking amplifier 201 to a short (0), the first offset line 203 and a second A first transformer 205 installed between the offset lines 204 and performing a load modulation function, and connected to the second offset line 204 and the first transformer 205 to load the load. Including a second transformer 206 for converting It is made to the structure.

Here, the conventional doherty amplifier 100 has a conventional Doherty amplifier structure, and the main amplifier 101 and the peaking amplifier 102, and the main amplifier 101 and the peaking amplifier 102, respectively. A second 90 [deg.] Hybrid divider 103 for distributing power of the input signal by a 90 [deg.] Phase difference, and a load modulation connected to each output terminal of the main amplifier 101 and the peaking amplifier 102 to perform load modulation. A third transformer 104 and a fourth transformer 105 connected to the peaking amplifier 102 and the third transformer 104 to convert a load are configured. In addition, a third offset line 106 for directing the output load of the main amplifier 101 to the short (0) and a fourth offset line for directing the output load of the peaking amplifier 102 to the short (0) 107) further comprises a structure consisting of.

90 ° hybrid divider 202 has an input connected to an RF IN port and an output connected to a second 90 ° hybrid divider 103 and an embedded peaking amplifier 201 of the conventional Doherty amplifier 100. In this case, the power of the input signal is distributed to each of the embedded peaking amplifier 201 and the conventional Doherty amplifier 100 by a 90 ° phase difference.

An embedded peaking amplifier 201 is further added to the structure of the Conventional Doherty Amplifier 100, which provides a 6dB backoff at the P1dB reference output of the Conventional Doherty Amplifier 100. Maximum efficiency can be obtained at a lower point than the point, and maximum output power can be obtained at a point increased by 3 dB from the existing P1dB. Specifically, it is connected in parallel with the conventional Doherty amplifier 100 and is installed between the 90 ° hybrid divider 202 and the second offset line 204 to amplify the basic signal of the input signal.

The offset lines 203 and 204 are composed of two offset lines, and are connected and installed between the fourth transformer 105 and the first transformer 205 of the conventional Doherty amplifier 100 to provide the conventional Doherty amplifier 100. Is connected between the first offset line 203 and the embedded peaking amplifier 201 and the first and second transformers 205 and 206 to direct the output load of the circuit to the short (0). Is a structure having a second offset line 204 for inducing an output load of N) to the short (0).

The transformers 205 and 206 are formed of two transformers. The first transformer 205 is provided between the first offset line 203 and the second offset line 204 to perform a load modulation function. And a second transformer 206 connected to the second offset line 204 and the first transformer 205 to convert a load.

Hereinafter, an operation of the embedded bias mixed power amplifier of FIG. 1 having such a structure will be described with reference to FIGS. 2A and 2B.

2A and 2B are diagrams illustrating the operation of the embedded bias mixed power amplifier according to the present invention, and FIG. 2A is a diagram illustrating the operation of the embedded bias mixed power amplifier when the input power is at a low level. 2B is a diagram illustrating the operation of the embedded bias mixed power amplifying apparatus which is performed when the input power is at a high level.

* Operation principle

① Low level

When the input power is at a low level, the output stage of the peaking amplifier appears to be open due to bias conditions, so the main amplifier of the conventional Doherty amplifier is short-circuited and the main amplifier by the quaterwave line. The output power of the main amplifier is delivered to the load.

② High level

- if the input power is high level, while increasing the output power becomes the output load (load) condition of the peaking amplifier (Peaking amplifier) reaches the R _opt General Class is the maximum output power and the same power of AB load (Loa) d To be delivered.

In this case, unlike the conventional doherty, the embedded peaking amplifier added according to the present invention simultaneously operates, and the maximum output power may be increased by 3 dB.

As described above, the present invention adds an embedded peaking amplifier to the structure of the conventional Doherty amplifier, so that the point is more than 6 dB backoff point at the P1dB reference output of the conventional Doherty amplifier. Maximum efficiency is obtained at low points, and maximum output power can be obtained at points increased by 3 dB from the existing P1dB.

3 is a graph showing the effect of the embedded bias mixed power amplifier according to the present invention.

As shown in FIG. 3, the features of the embedded bias mixed power amplifier according to the present invention are as follows.

* Characteristic

Conventional doherty amplifier architecture achieves maximum efficiency at 6dB backoff at the P1dB reference output power.

On the other hand, the embedded bias mixed power amplifier structure proposed by the present invention has a lower point than a conventional doherty amplifier (i.e., a point lower than one 6 dB backoff at P1 dB reference output power). Maximum efficiency can be achieved, and an embedded peaking amplifier can be added to achieve maximum output power at 3dB increments from conventional P1dB.

Description of the Related Art [0002]
100: Conventional Doherty Amplifier 101: Main Amplifier
102 peaking amplifier 103 second 90 ° hybrid splitter
104: third transformer 105: fourth transformer
106: third offset line 107: fourth offset line
201: embedded picking amplifier 202: 90 ° hybrid splitter
203: first offset line 204: second offset line
205: first transformer 206: second transformer

Claims (2)

Conventional doherty amplifiers;
An embedded peaking amplifier connected in parallel to the conventional Doherty amplifier to amplify a basic signal of an input signal;
A 90 ° hybrid divider for distributing power of an input signal by 90 ° out of phase with each of the embedded peaking amplifier and the conventional Doherty amplifier;
A first offset line for inducing an output load of the conventional Doherty amplifier to a short (0);
A second offset line for inducing an output load of the embedded peaking amplifier to a short (0);
A first transformer disposed between the first offset line and the second offset line to perform a load modulation function; And
And a second transformer connected to the second offset line and the first transformer to convert a load. The method of claim 1,
The conventional doherty amplifier
A second 90 [deg.] Hybrid divider for distributing power of an input signal by a 90 [deg.] Phase difference to each of the main amplifier and the peaking amplifier, and a load modulation connected to each output terminal of the main amplifier and the peaking amplifier. And a fourth transformer connected to the picking amplifier and the third transformer to convert a load.

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