(19)
(11)EP 3 018 823 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
06.05.2020 Bulletin 2020/19

(21)Application number: 13891744.8

(22)Date of filing:  21.08.2013
(51)Int. Cl.: 
H03F 1/02  (2006.01)
H03F 1/56  (2006.01)
H03F 3/60  (2006.01)
H04B 1/04  (2006.01)
(86)International application number:
PCT/CN2013/081927
(87)International publication number:
WO 2015/024208 (26.02.2015 Gazette  2015/08)

(54)

BALANCED DOHERTY POWER AMPLIFIER CIRCUIT AND WIRELESS TRANSMITTER

AUSGEGLICHENE DOHERTY-LEISTUNGSVERSTÄRKERSCHALTUNG UND DRAHTLOSER SENDER

CIRCUIT D'AMPLIFICATEUR DE PUISSANCE DE DOHERTY ÉQUILIBRÉ ET ÉMETTEUR SANS FIL


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
11.05.2016 Bulletin 2016/19

(73)Proprietor: Huawei Technologies Co., Ltd.
Longgang District Shenzhen, Guangdong 518129 (CN)

(72)Inventors:
  • WANG, Kun
    Shenzhen Guangdong 518129 (CN)
  • SU, Yongge
    Shenzhen Guangdong 518129 (CN)
  • WANG, Laiqing
    Shenzhen Guangdong 518129 (CN)

(74)Representative: Goddar, Heinz J. 
Boehmert & Boehmert Anwaltspartnerschaft mbB Pettenkoferstrasse 22
80336 München
80336 München (DE)


(56)References cited: : 
WO-A1-2009/009987
CN-A- 101 783 652
DE-A1-102010 034 067
US-A1- 2008 238 544
CN-A- 1 943 106
CN-A- 102 427 332
DE-A1-102011 079 613
US-A1- 2010 176 885
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present invention relates to the field of wireless communication technologies, and in particular, to a radio transmitter which is comprising a balanced Doherty power amplifier circuit.

    BACKGROUND



    [0002] In a wireless communication technology, a power amplifier circuit is located at a front end of an emitter, and is used to implement signal amplification, so as to meet a power requirement for a transmitted signal. To meet a requirement on high power, as shown in FIG. 1, an existing power amplifier circuit is a balanced Doherty (Doherty) power amplifier circuit, which is equivalent to two Doherty amplifiers 1. In each Doherty amplifier 1, an input end of a peak amplifier P is connected to an input end of the power amplifier circuit by using a one-fourth wavelength line 2, and an input end of a main amplifier M is connected to an input end of the power amplifier. That is, a same input signal is input to two peak amplifiers and two main amplifiers. A working principle of the balanced Doherty power amplifier circuit lies in active-load pulling, where load impedance of the main amplifier P and the peak amplifier M changes with different power of an input signal. Specifically, when input power is low and the peak amplifier P is not working, because of an impedance transformation function of the one-fourth wavelength line, a load corresponding to the main amplifier M is 100 ohms; compared with a working condition with a load of 50 ohms, saturated output power of the main amplifier M is reduced by 3 dB, and efficiency is relatively high in a case of low power output. When the input power increases, the peak amplifier P starts to work, and the load of the main amplifier M changes from 100 ohms to 50 ohms; in a case in which an output peak voltage remains in a saturated state, the output power gradually increases and efficiency of the main amplifier M is still high; the load of the peak amplifier P changes from infinity to 50 ohms. When the input power continues to increase until both the main amplifier M and the peak amplifier P reach their peak power, both the load corresponding to the main amplifier M and that corresponding to the peak amplifier P are 50 ohms. A matching unit in the figure is configured for load matching in a signal amplification process.

    [0003] However, because working processes of the peak amplifier and the main amplifier, as well as the devices themselves, are different, time delays, phases, or working statuses of two branches in each Doherty amplifier cannot precisely match; as a result, efficiency of the entire power amplifier circuit is reduced.

    [0004] DE 10 2010 034 067 A discloses a high-frequency power amplifier comprising a broadband amplifier, a Doherty extension and a coupling device. In this context, the broadband amplifier provides a power splitter, a main amplifier path and an auxiliary amplifier path. The Doherty extension provides a first offset line, a second offset line and an impedance inverter. The broadband amplifier amplifies an input signal and supplies the amplified signal to the Doherty extension or to the coupling device.

    [0005] DE 102011079613 A1 discloses an amplifier having a main amplifier circuit, an auxiliary amplifier circuit and a signal generator. Output terminals of the main amplifier circuit and the auxiliary amplifier circuit are connected according to the Doherty principle. The signal generating means is configured to directly generate a main amplifier signal as an input signal of the main amplifier circuit and an auxiliary amplifier signal as an input signal of the auxiliary amplifier circuit.

    [0006] US 2008/0238544 A1 discloses a method of optimizing performance of a multiple path amplifier includes: splitting an input signal to derive a respective sub-signal for each branch of the multiple path amplifier; independently pre-distorting each sub-signal using a known performance characteristic of its associated branch of the multiple path amplifier; and supplying each pre-distorted sub-signal to its associated branch of the multiple amplifier.

    SUMMARY



    [0007] The present invention provides a radio transmitter which comprises a balanced Doherty power amplifier circuit and which increases efficiency of a power amplifier circuit. To resolve the foregoing technical problem, the present invention provides a radio transmitter as defined in claim 1.

    [0008] According to the balanced Doherty power amplifier circuit and the radio transmitter that are provided in the present invention, a peak amplifier and a main amplifier in the balanced Doherty power amplifier circuit receive different input signals, so that two channels of input signals can be first processed separately to implement matching and optimization of the peak amplifier and the main amplifier, thereby increasing efficiency of the balanced Doherty power amplifier circuit.

    BRIEF DESCRIPTION OF DRAWINGS



    [0009] To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

    FIG. 1 is a schematic structural diagram of a balanced Doherty power amplifier circuit in the prior art;

    FIG. 2 is a schematic structural diagram of a balanced Doherty power amplifier circuit according to an example;

    FIG. 3 is a schematic structural diagram of a balanced Doherty power amplifier circuit according to an embodiment of the present invention; and

    FIG. 4 is a structural block diagram of a radio transmitter according to an embodiment of the present invention.


    DESCRIPTION OF EMBODIMENTS



    [0010] The following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely some but not all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

    [0011] As shown in FIG. 2, an example provides a balanced Doherty power amplifier circuit, including: a first peak amplifier PI, where an input end of the first peak amplifier PI is connected to a first input end Vin1 of the balanced Doherty power amplifier circuit; a first matching unit 31, where an input end of the first matching unit 31 is connected to an output end of the first peak amplifier PI, and an output end of the first matching unit 31 is connected to an output end Vout of the balanced Doherty power amplifier circuit; a first main amplifier M1, where an input end of the first main amplifier M1 is connected to a second input end Vin2 of the balanced Doherty power amplifier circuit, and an output end of the first main amplifier M1 is connected to the input end of the first matching unit 31 by using a one-fourth wavelength line 2; a second peak amplifier P2, where an input end of the second peak amplifier P2 is connected to the first input end Vin1 of the balanced Doherty power amplifier circuit; a second matching unit 32, where an input end of the second matching unit 32 is connected to an output end of the second peak amplifier P2, and an output end of the second matching unit 32 is connected to the output end Vout of the balanced Doherty power amplifier circuit; and a second main amplifier M2, where an input end of the second main amplifier M2 is connected to the second input end Vin2 of the balanced Doherty power amplifier circuit, and an output end of the second main amplifier M2 is connected to the input end of the second matching unit 32 by using a one-fourth wavelength line 2.

    [0012] Specifically, a branch at which the first peak amplifier PI is located and a branch at which the first main amplifier M1 is located form a Doherty amplifier; a branch at which the second peak amplifier P2 is located and a branch at which the second main amplifier M2 is located form another Doherty amplifier. A specific working principle of the balanced Doherty power amplifier circuit is similar to that in the prior art, and an only difference lies in that: because the two peak amplifiers are connected to a same input end, and the two main amplifiers are connected to another input end, the peak amplifiers and the main amplifiers separately receive different input signals. A peak amplifier and a main amplifier in the prior art can only receive a same input signal, and therefore a one-fourth wavelength line needs to be disposed at an input end of each peak amplifier to perform impedance transformation. However, in this example, because a peak amplifier and a main amplifier separately receive two different channels of input signals, impedance transformation may be first performed, by using a digital signal processing module, on a signal that needs to enter the peak amplifier, and then the signal that undergoes impedance transformation is input to the first input end Vin1 of the balanced Doherty power amplifier circuit, without disposing a one-fourth wavelength line at an input end of the peak amplifier. In addition, working processes of the peak amplifier and the main amplifier, as well as the devices themselves, are different, and the peak amplifier and the main amplifier in the prior art receive a same input signal; therefore, the main amplifier is over-pushed after the main amplifier reaches a saturation point, a peak amplifier works in an under-saturated state or over-saturated state because an input power of the peak amplifier cannot be precisely controlled, and time delays and phases of the peak amplifier and the main amplifier are inconsistent. The foregoing problems cause an efficiency decrease of an entire balanced Doherty power amplifier circuit. However, for the balanced Doherty power amplifier circuit in this example, according to differences of working processes of the peak amplifier and the main amplifier and the devices themselves, two channels of input signals are separately processed by a digital signal processing module, so as to change time delays and phases of the peak amplifier and the main amplifier or change a switching characteristic, and the like of the peak amplifier. That is, the two channels of signals are processed, so as to implement matching and optimization of the peak amplifier and the main amplifier, thereby increasing efficiency of the balanced Doherty power amplifier circuit. In addition, because only single input is changed to dual input, and a basic principle and a working process of the balanced Doherty power amplifier circuit remain unchanged, it is ensured that linear performance does not deteriorate.

    [0013] According to the balanced Doherty power amplifier circuit in this example, a peak amplifier and a main amplifier receive different input signals, so that two channels of input signals can be first processed separately to implement matching and optimization of the peak amplifier and the main amplifier, thereby increasing efficiency of the balanced Doherty power amplifier circuit.

    [0014] As shown in FIG. 3, in an embodiment of the present invention, the input end of the first peak amplifier PI is connected to the first input end Vin1 of the balanced Doherty power amplifier circuit by using a one-fourth wavelength line 2; and the input end of the second peak amplifier P2 is connected to the first input end Vin1 of the balanced Doherty power amplifier circuit by using a one-fourth wavelength line 2.

    [0015] Another specific structure of the balanced Doherty power amplifier circuit is the same as that in the foregoing example; a working process of the circuit is similar to that in the foregoing example, and an only difference lies in that: the peak amplifier can perform impedance transformation by using a one-fourth wavelength line 2, without requiring a digital signal processing module to perform impedance transformation processing on an input signal.

    [0016] According to the balanced Doherty power amplifier circuit in this embodiment of the present invention, a peak amplifier and a main amplifier receive different input signals, so that two channels of input signals can be first processed separately to implement matching and optimization of the peak amplifier and the main amplifier, thereby increasing efficiency of the balanced Doherty power amplifier circuit.

    [0017] As shown in FIG. 4, an embodiment of the present invention further provides a radio transmitter, including a digital domain signal processing module 4 and a balanced Doherty power amplifier circuit 5 that is described above, where the digital domain signal processing module 4 is connected to a first input end Vin1 and a second input end Vin2 of the balanced Doherty power amplifier circuit 5, and is configured to provide an input signal that matches the balanced Doherty power amplifier circuit 5. The balanced Doherty power amplifier circuit 5 amplifies the input signal, and then outputs the input signal to a device, for example, a duplexer, for transmitting.

    [0018] A specific structure, a principle, and a working process of the balanced Doherty power amplifier circuit are the same as those in the foregoing embodiment, and details are not described herein again.

    [0019] According to the radio transmitter in this embodiment of the present invention, a peak amplifier and a main amplifier in the balanced Doherty power amplifier circuit receive different input signals, so that two channels of input signals can be first processed separately to implement matching and optimization of the peak amplifier and the main amplifier, thereby increasing efficiency of the balanced Doherty power amplifier circuit.

    [0020] Based on the foregoing descriptions of the implementation manners, a person skilled in the art may clearly understand that the present invention may be implemented by software in addition to necessary universal hardware or by hardware only. In most circumstances, the former is a preferred implementation manner.

    [0021] The foregoing descriptions are merely specific implementation manners of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the attached claim.


    Claims

    1. A radio transmitter, comprising:
    a digital domain signal processing module (4) and a balanced Doherty power amplifier circuit (5), wherein the balanced Doherty power amplifier circuit (5) comprises:

    a first peak amplifier (P1), wherein an input end of the first peak amplifier (P1) is connected to a first input end (Vin1) of the balanced Doherty power amplifier circuit (5);

    a first matching unit (31), wherein an input end of the first matching unit (31) is directly connected to an output end of the first peak amplifier (P1), and an output end of the first matching unit (31) is connected to an output end (Vout) of the balanced Doherty power amplifier circuit (5);

    a first main amplifier (M1), wherein an input end of the first main amplifier (M1) is directly connected to a second input end (Vin2) of the balanced Doherty power amplifier circuit (5), and an output end of the first main amplifier (M1) is directly connected to the input end of the first matching unit (31) via a respective one-fourth wavelength line (2);

    a second peak amplifier (P2), wherein an input end of the second peak amplifier (P2) is connected to the first input end (Vin1) of the balanced Doherty power amplifier circuit (5);

    a second matching unit (32), wherein an input end of the second matching unit (32) is directly connected to an output end of the second peak amplifier (P2), and an output end of the second matching unit (32) is connected to the output end (Vout) of the balanced Doherty power amplifier circuit (5); and

    a second main amplifier (M2), wherein an input end of the second main amplifier (M2) is directly connected to the second input end (Vin2) of the balanced Doherty power amplifier circuit (5), and an output end of the second main amplifier (M2) is directly connected to the input end of the second matching unit (32) via a respective one-fourth wavelength line (2);

    the input end of the first peak amplifier (P1) is directly connected to the first input end (Vim) of the balanced Doherty power amplifier circuit (5) via a respective one-fourth wavelength line (2); and

    the input end of the second peak amplifier (P2) is directly connected to the first input end (Vim) of the balanced Doherty power amplifier circuit (5) via a respective one-fourth wavelength line (2);

    the digital domain signal processing module (4) is connected to the first input end (Vim) and the second input end (Vin2) of the balanced Doherty power amplifier circuit (5), and is configured to provide an input signal that matches the balanced Doherty power amplifier circuit (5).


     


    Ansprüche

    1. Funksender, der Folgendes umfasst:
    ein digitales Domänensignalverarbeitungsmodul (4) und einen symmetrischen Doherty-Leistungsverstärkerschaltkreis (5), wobei der symmetrische Doherty-Leistungsverstärkerschaltkreis (5) Folgendes umfasst:

    einen ersten Spitzenverstärker (P1), wobei ein Eingangsende des ersten Spitzenverstärkers (P1) mit einem ersten Eingangsende (Vin1) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist;

    eine erste Abgleicheinheit (31), wobei ein Eingangsende der ersten Abgleicheinheit (31) direkt mit einem Ausgangsende des ersten Spitzenverstärkers (P1) verbunden ist und ein Ausgangsende der ersten Abgleicheinheit (31) mit einem Ausgangsende (Vout) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist;

    einen ersten Hauptverstärker (M1), wobei ein Eingangsende des ersten Hauptverstärkers (M1) direkt mit einem zweiten Eingangsende (Vin2) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist und ein Ausgangsende des ersten Hauptverstärkers (M1) über eine jeweilige Viertelwellenlängenleitung (2) direkt mit dem Eingangsende der ersten Abgleicheinheit (31) verbunden ist;

    einen zweiten Spitzenverstärker (P2), wobei ein Eingangsende des zweiten Spitzenverstärkers (P2) mit dem ersten Eingangsende (Vin1) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist;

    eine zweite Abgleicheinheit (32), wobei ein Eingangsende der zweiten Abgleicheinheit (32) direkt mit einem Ausgangsende des zweiten Spitzenverstärkers (P2) verbunden ist und ein Ausgangsende der zweiten Abgleicheinheit (32) mit dem Ausgangsende (Vout) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist; und

    einen zweiten Hauptverstärker (M2), wobei ein Eingangsende des zweiten Hauptverstärkers (M2) direkt mit dem zweiten Eingangsende (Vin2) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist und ein Ausgangsende des zweiten Hauptverstärkers (M2) über eine jeweilige Viertelwellenlängenleitung (2) direkt mit dem Eingangsende der zweiten Abgleicheinheit (32) verbunden ist;

    wobei das Eingangsende des ersten Spitzenverstärkers (P1) über eine jeweilige Viertelwellenlängenleitung (2) direkt mit dem ersten Eingangsende (Vin1) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist; und

    wobei das Eingangsende des zweiten Spitzenverstärkers (P2) über eine jeweilige Viertelwellenlängenleitung (2) direkt mit dem ersten Eingangsende (Vin1) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist;

    wobei das digitale Domänensignalverarbeitungsmodul (4) mit dem ersten Eingangsende (Vin1) und dem zweiten Eingangsende (Vin2) des symmetrischen Doherty-Leistungsverstärkerschaltkreises (5) verbunden ist und zum Bereitstellen eines Eingangssignals konfiguriert ist, das den symmetrischen Doherty-Leistungsverstärkerschaltkreis (5) abgleicht.


     


    Revendications

    1. Émetteur radio, comprenant :
    un module de traitement de signal dans le domaine numérique (4) et un circuit d'amplificateur de puissance Doherty symétrique (5), dans lequel le circuit d'amplificateur de puissance Doherty symétrique (5) comprend :

    un premier amplificateur de crête (P1), dans lequel une extrémité d'entrée du premier amplificateur de crête (P1) est connectée à une première extrémité d'entrée (Vin1) du circuit d'amplificateur de puissance Doherty symétrique (5) ;

    une première unité d'adaptation (31), dans lequel une extrémité d'entrée de la première unité d'adaptation (31) est connectée directement à une extrémité de sortie du premier amplificateur de crête (P1), et une extrémité de sortie de la première unité d'adaptation (31) est connectée à une extrémité de sortie (Vout) du circuit d'amplificateur de puissance Doherty symétrique (5) ;

    un premier amplificateur principal (M1), dans lequel une extrémité d'entrée du premier amplificateur principal (M1) est directement connectée à une deuxième extrémité d'entrée (Vin2) du circuit d'amplificateur de puissance Doherty symétrique (5), et une extrémité de sortie du premier amplificateur principal (M1) est connectée directement à l'extrémité d'entrée de la première unité d'adaptation (31) par l'intermédiaire d'une ligne quart d'onde respective (2) ;

    un second amplificateur de crête (P2), dans lequel une extrémité d'entrée du second amplificateur de crête (P2) est connectée à la première extrémité d'entrée (Vin1) du circuit d'amplificateur de puissance Doherty symétrique (5) ;

    une seconde unité d'adaptation (32), dans lequel une extrémité d'entrée de la deuxième unité d'adaptation (32) est connectée directement à une extrémité de sortie du second amplificateur de crête (P2), et une extrémité de sortie de la seconde unité d'adaptation (32) est connectée à l'extrémité de sortie (Vout) du circuit d'amplificateur de puissance Doherty symétrique (5) ; et

    un second amplificateur principal (M2), dans lequel une extrémité d'entrée du second amplificateur principal (M2) est connectée directement à la seconde extrémité d'entrée (Vin2) du circuit d'amplificateur de puissance Doherty symétrique (5), et une extrémité de sortie du second amplificateur principal (M2) est connectée directement à l'extrémité d'entrée de la seconde unité d'adaptation (32) par l'intermédiaire d'une ligne quart d'onde respective (2) ;

    l'extrémité d'entrée du premier amplificateur de crête (P1) est directement connectée à la première extrémité d'entrée (Vin1) du circuit d'amplificateur de puissance Doherty symétrique (5) par l'intermédiaire d'une ligne quart d'onde respective (2) ; et

    l'extrémité d'entrée du second amplificateur de crête (P2) est directement connectée à la première extrémité d'entrée (Vin1) du circuit d'amplificateur de puissance Doherty symétrique (5) par l'intermédiaire d'une ligne quart d'onde respective (2) ;

    le module de traitement de signal dans le domaine numérique (4) est connecté à la première extrémité d'entrée (Vin1) et à la seconde extrémité d'entrée (Vin2) du circuit d'amplificateur de puissance Doherty symétrique (5), et est configuré pour fournir un signal d'entrée qui correspond au circuit d'amplificateur de puissance Doherty symétrique (5).


     




    Drawing









    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description