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CN-122029738-A - Power amplifying circuit

CN122029738ACN 122029738 ACN122029738 ACN 122029738ACN-122029738-A

Abstract

Even when the impedance at the output side is low when the output ends of the carrier amplifier and the peak amplifier constituting the doherty amplifier are viewed, the characteristic of a wide band is realized. The power amplification circuit includes a carrier amplifier and a peak amplifier that constitute a doherty amplification circuit, a first transformer having a primary winding connected to an output of the carrier amplifier, a second transformer having a primary winding connected to an output of the peak amplifier, a signal line having one end of a secondary winding of the first transformer connected to one end of a secondary winding of the second transformer, a first capacitor having a second capacitor connected to the primary winding of the first transformer, and a third capacitor connected to the primary winding of the second transformer, wherein one end of the first capacitor is connected to the signal line, the other end of the first capacitor is connected to a reference potential, and formula (1) is satisfied when a sum of capacitance values of the first capacitor and the signal line is C T , an angular frequency is ω 0 , and a load impedance is Z M . 。

Inventors

  • SHOHEI IMAI

Assignees

  • 株式会社村田制作所

Dates

Publication Date
20260512
Application Date
20241030
Priority Date
20231117

Claims (7)

  1. 1. A power amplifying circuit, comprising: A carrier amplifier and a peak amplifier constituting a doherty amplifying circuit; a first transformer, the primary winding of which is connected to the output end of the carrier amplifier; a second transformer, the primary winding of which is connected to the output end of the peak amplifier; a signal line connecting one end of the secondary winding of the first transformer with one end of the secondary winding of the second transformer; A first capacitor; a second capacitor connected in parallel with the primary winding of the first transformer, and A third capacitor connected in parallel with the primary winding of the second transformer, Wherein one end of the first capacitor is connected with the signal line, The other end of the first capacitor is connected with a reference potential, When the sum of the capacitance values of the first capacitor and the signal line is C T , the angular frequency is ω 0 , and the load impedance is Z M , equation (1) is satisfied, 。
  2. 2. The power amplification circuit of claim 1, wherein, The ratio Z tar /Z M of the target impedance Z tar to the load impedance Z M satisfies the equation (2), 。
  3. 3. The power amplification circuit according to claim 1 or 2, further comprising: a first inductor connected in series between one end of the first capacitor and the secondary winding of the first transformer, and A second inductor connected in series between one end of the first capacitor and the secondary winding of the second transformer.
  4. 4. The power amplification circuit of claim 3, wherein, When the inductance value of the first inductor is L T 'and the capacitance value of the second capacitor is C1, and when the inductance value of the second inductor is L T ' and the capacitance value of the third capacitor is C1, equation (4) is satisfied, 。
  5. 5. A power amplifying circuit according to claim 1 or 3, further comprising: a fourth capacitor connected in series between one end of the first capacitor and the secondary winding of the first transformer, and A fifth capacitor connected in series between one end of the first capacitor and the secondary winding of the second transformer.
  6. 6. The power amplification circuit of claim 5, wherein, When the capacitance value of the fourth capacitor and the capacitance value of the fifth capacitor are C2 and C2' =c2/(1- ω 0 2 L T C 2 ), equation (5) is satisfied, 。
  7. 7. The power amplification circuit according to any one of claims 1 to 6, wherein, The other end of the secondary winding of the first transformer is connected to an output terminal via a matching circuit, The other end of the secondary winding of the second transformer is connected with a reference potential.

Description

Power amplifying circuit Technical Field The present invention relates to a power amplifying circuit. Background Non-patent document 1 discloses a power amplifier circuit having a doherty amplifier structure. Fig. 6 of non-patent document 1 describes a conventional power amplifier circuit. The power amplification circuit described in non-patent document 1 is configured such that an inverter that can be regarded as a current source is connected to the output side of a peak amplifier, and an inverter that can be regarded as a voltage source is connected to the output side of a carrier amplifier. Non-patent document 1 discloses that a doherty amplifier having a matching fractional bandwidth of a wide band is obtained by this configuration. Prior art literature Non-patent literature Non-patent literature 1：Shohei Imai et al."Bandwidth_Optimization_of_Doherty_Power_Amplifier_Based_on_Source_Converters_for_5G_Mobile_Handsets",IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES,VOL.70,NO.1,JANUARY 2022 Disclosure of Invention Problems to be solved by the invention In the power amplification circuit described in non-patent document 1, the converter which can be regarded as a current source is a converter which outputs a high impedance in a state where the high impedance is maintained. On the other hand, a converter which can be regarded as a voltage source is a converter which converts a high impedance into a low impedance and outputs the low impedance. When the impedance at the output side is low when the output ends of the carrier amplifier and the peak amplifier are viewed, there is a problem that it is difficult to obtain good characteristics over a wide frequency range, that is, it is difficult to realize a wide frequency band characteristic due to the limitation of the conversion ratio of the inverter. The present disclosure has been made in view of the above-described circumstances, and an object thereof is to provide a power amplification circuit capable of realizing a broadband characteristic even when the impedance at the output side is low when the output ends of a carrier amplifier and a peak amplifier constituting a doherty amplifier are viewed. Solution for solving the problem In order to solve the above problems and achieve the object, a power amplification circuit according to an embodiment of the present disclosure includes a carrier amplifier and a peak amplifier that constitute a doherty amplification circuit, a first transformer having a primary side connected to an output of the carrier amplifier, a second transformer having a primary side connected to an output of the peak amplifier, a signal line having one end of a secondary side of the first transformer connected to one end of a secondary side of the second transformer, and a first capacitor having one end connected to the signal line and the other end connected to a reference potential, wherein when a sum of capacitance values of the first capacitor and the signal line is C T、, a frequency to be used is ω 0(ω0 =2pi f, and a load impedance is Z M, formula (1) is satisfied. ADVANTAGEOUS EFFECTS OF INVENTION According to the present disclosure, even in the case where the impedance at the output side is low when the output ends of the carrier amplifier and the peak amplifier constituting the doherty amplifier are viewed, the characteristic of a wide band can be achieved. Drawings Fig. 1 is a block diagram showing a power amplifying circuit of a first embodiment of the present disclosure. Fig. 2 is a block diagram showing a power amplifying circuit of a second embodiment of the present disclosure. Fig. 3 is a block diagram showing a power amplifying circuit of a third embodiment of the present disclosure. Fig. 4 is a block diagram showing a power amplifying circuit of a fourth embodiment of the present disclosure. Fig. 5 is a diagram showing an example of matching fractional bandwidths with respect to coupling coefficients of a transformer. Fig. 6 is a diagram showing a relationship between the coupling coefficient of the transformer on the carrier side and the peak side and the matching score bandwidth. Detailed Description Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In the following description of each embodiment, the same or equivalent components as those of the other embodiments are denoted by the same reference numerals, and the description thereof is simplified or omitted. The present invention is not limited to the embodiments. The constituent elements of each embodiment include constituent elements that can be easily replaced by a person skilled in the art, or substantially the same constituent elements. The structures described below can be appropriately combined. The structure may be omitted, replaced, or changed without departing from the gist of the invention. (First embodiment) (Structure) Fig. 1 is a diagram showing a power amplifying circuit 100 of a first embodiment of th