Matching circuit and power amplifier circuit

Abstract

The present invention provides a matching circuit for improving the efficiency of a power amplifier circuit. The matching circuit comprises: an input terminal to which an amplified signal is input from a power amplifier; an output terminal; a first inductor having one end connected to the input terminal and the other end connected to the output terminal; a first capacitor connected in parallel to the first inductor; a second inductor having one end connected to the input terminal and the other end connected to ground; and a first series resonant circuit connected in parallel to the second inductor.

Description

Technical Field

[0001] The present disclosure relates to a matching circuit and a power amplifier circuit. Background Art

[0002] In mobile communication terminals such as cellular phones, a power amplifier circuit is used to amplify an RF (Radio Frequency) signal transmitted to a base station. The power amplifier circuit is provided with a matching circuit in order to improve its efficiency.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent document 1: US9660606

[0006] The matching circuit described in Patent Document 1 includes a first metal trace having a first end and a second end. The first end of the first metal trace is connected to a voltage source, and the second end is connected to an output of a power amplifier. In addition, the matching circuit described in Patent Document 1 includes a second metal trace having a third end and a fourth end. The third end of the second metal trace is connected to the second end of the first metal trace. The fourth end of the second metal trace is connected to an output terminal. Furthermore, a capacitor is connected in parallel to the first metal trace.

[0007] However, in the matching circuit described in Patent Document 1, since the second harmonic impedance in the output of the power amplifier cannot be controlled, the efficiency of the power amplifier circuit may be reduced. Summary of the invention

[0008] Problems to be solved by the invention

[0009] Therefore, an object of the present disclosure is to improve the efficiency of a power amplifier circuit.

[0010] Technical solutions to solve problems

[0011] One aspect of the present disclosure relates to a matching circuit comprising: an input terminal to which an amplified signal is input from a power amplifier; an output terminal; a first inductor having one end connected to the input terminal and the other end connected to the output terminal; a first capacitor connected in parallel with the first inductor; a second inductor having one end connected to the input terminal and the other end connected to ground; and a first series resonant circuit connected in parallel with the second inductor.

[0012] An aspect of the present disclosure relates to a matching circuit arranged between a first power amplifier and a second power amplifier, wherein the matching circuit comprises: an input terminal to which an amplified signal is input from the first power amplifier; an output terminal; a tenth inductor having one end connected to the input terminal and the other end connected to the output terminal; a sixth capacitor connected in parallel to the tenth inductor; and an eleventh inductor having one end connected to the output terminal and the other end connected to ground.

[0013] Effects of the Invention

[0014] According to the present disclosure, it is possible to provide a matching circuit that improves the efficiency of a power amplifier circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram schematically showing the configuration of a power amplifier circuit according to the first embodiment.

[0016] Figure 2A It is a diagram showing an outline of a matching circuit.

[0017] Figure 2B is a diagram showing an equivalent circuit of a matching circuit.

[0018] Figure 3 is the Smith chart at the fundamental frequency of the matching circuit.

[0019] Figure 4 It is a diagram showing an example of the configuration of a power amplifier circuit according to the second embodiment.

[0020] Figure 5 It is a diagram showing an example of the configuration of a power amplifier circuit according to the third embodiment.

[0021] Figure 6 It is a diagram showing an example of the configuration of a power amplifier circuit according to the fourth embodiment.

[0022] Figure 7 It is a diagram showing an example of the configuration of a power amplifier circuit according to the fifth embodiment.

[0023] Figure 8 It is a diagram showing an example of the configuration of a power amplifier circuit according to the sixth embodiment.

[0024] Fig. 9 This is a diagram showing an example of the configuration of a power amplifier circuit according to the seventh embodiment.

[0025] Fig.10 This is a diagram showing an example of the configuration of a power amplifier circuit according to the eighth embodiment.

[0026] Fig.11This is a diagram showing an example of the configuration of a power amplifier circuit according to the ninth embodiment.

[0027] Fig.12 It is a diagram showing an example of the configuration of a power amplifier circuit according to the tenth embodiment.

[0028] Fig.13 is a Smith chart showing an example of load impedance with respect to frequency changes as viewed from a driver amplifier.

[0029] Fig.14 It is a diagram showing an equivalent circuit of a matching circuit according to the tenth embodiment.

[0030] Fig.15 This is a Smith chart showing an example of the shift of the load impedance in the fundamental wave frequency band of the matching circuit according to the tenth embodiment.

[0031] Fig.16 This is a diagram showing an example of the structure of a first modified example of the power amplifier circuit according to the tenth embodiment.

[0032] Fig.17 This is a diagram showing an example of the structure of a second modified example of the power amplifier circuit according to the tenth embodiment.

[0033] Description of Reference Numerals

[0034] 100~1000: power amplifier circuit, 110~1011: power amplifier, 120~1020: matching circuit. DETAILED DESCRIPTION

[0035] Hereinafter, each embodiment of the present disclosure will be described with reference to each drawing. Here, circuit elements with the same reference numerals represent the same circuit elements, and repeated descriptions are omitted.

[0036] <Configuration of Power Amplifier Circuit 100 According to First Embodiment>

[0037] Figure 11 is a diagram showing an overview of the structure of the power amplifier circuit 100 involved in the first embodiment. The power amplifier circuit 100 is mounted on a mobile communication device such as a mobile phone, amplifies the power of the input signal RFin to the level required for transmission to the base station, and outputs it as an output signal RFout. The input signal RFin is, for example, a radio frequency (RF: Radio Frequency) signal modulated by an RFIC (Radio Frequency Integrated Circuit) or the like according to a given communication method. The communication standards of the input signal RFin include, for example, 2G (second generation mobile communication system), 3G (third generation mobile communication system), 4G (fourth generation mobile communication system), 5G (fifth generation mobile communication system), LTE (Long Term Evolution)-FDD (Frequency Division Duplex), LTE-TDD (Time Division Duplex), LTE-Advanced, or LTE-Advanced Pro, and the frequency is, for example, several hundred MHz to several tens of GHz. In addition, the communication standard and frequency of the input signal RFin are not limited to this.

[0038] The power amplifier circuit 100 includes, for example, a power amplifier 110 and a matching circuit 120 .

[0039] The power amplifier 110 amplifies the input RF signal and outputs it. The power amplifier 110 amplifies the input signal RFin input from the input terminal through the matching circuit (not shown), and outputs the RF signal RF1 (amplified signal). The power amplifier 110 includes transistors such as heterojunction bipolar transistors (HBT, Heterojunction Bipolar Transistor). In addition, the power amplifier 110 may also include field effect transistors (Metal-oxide-semiconductor Field-Effect Transistor, Metal Oxide Semiconductor Field Effect Transistor) instead of HBT. In this case, the collector, base, and emitter can be read as the drain, gate, and source, respectively. In addition, unless otherwise specified below, the case where the transistor is composed of HBT is used as an example for explanation.

[0040] The matching circuit 120 matches the impedance of the power amplifier circuit 100 with the impedance of the load. In addition, the matching circuit 120 makes the load impedance close to zero at even-order harmonics and makes the load impedance close to infinity at odd-order harmonics. That is, the power amplifier circuit 100 operates as a class F through the matching circuit 120. The matching circuit 120 is described in detail below.

[0041] <Configuration of Matching Circuit 120 >

[0042] like Figure 1 As shown, the matching circuit 120 includes an input terminal 121 to which an RF signal obtained by amplifying an input signal RFin from the power amplifier 110 is input, and an output terminal 122 to which an output signal RFout is output.

[0043] For example, in order to make the load impedance of the third harmonic close to infinity, the matching circuit 120 includes: an inductor 123 having one end connected to the input terminal 121 and the other end connected to the output terminal 122; and a capacitor 124 connected in parallel with the inductor 123. Infinite in the present invention is defined as an impedance that is approximately three times or more of the load impedance at the fundamental frequency.

[0044] In addition, the matching circuit 120 includes, for example, an inductor 125 having one end connected to the input terminal 121 and the other end connected to a given potential 127, and a resonance circuit 126 connected in parallel to the inductor 125. Here, the inductor 125 is preferably arranged to be magnetically coupled with the inductor 123, for example. Thus, the matching circuit 120 can adjust the load impedance at the fundamental frequency.

[0045] The resonance circuit 126 is, for example, a series resonance circuit, and makes the load impedance of the second harmonic close to zero. The so-called zero in the present invention is defined as, for example, an impedance that is approximately one-third of the load impedance at the fundamental frequency.

[0046] Here, it is preferable that the predetermined potential 127 connected to the other end of the inductor 125 is different from the power supply supplied to the power amplifier 110, for example, is ground.

[0047] The given potential 127 connected to the other end of the inductor 125 may be a power supply for the power amplifier 110. In this case, the power amplifier 110 supplies the variable power supply voltage Vcc controlled according to the envelope of the RF signal to the power amplifier circuit 100 via the power supply.

[0048] In the following description, a given potential is assumed to be “ground”.

[0049] <Function of Matching Circuit 120>

[0050] Reference Figure 2A , Figure 2B , Figure 3 , the function of the matching circuit 120 is described. Figure 2A It is a diagram showing an outline of a matching circuit. Figure 2B is a diagram showing an equivalent circuit of the matching circuit 120 . Figure 3is the Smith chart at the fundamental frequency of the matching circuit 120 .

[0051] Figure 2A The matching circuit 120 shown can be used as Figure 2B Based on this equivalent circuit, the behavior of the impedance of the matching circuit 120 at the fundamental frequency of the matching circuit 120 will be described.

[0052] exist Figure 3 , as an example, a case is shown where a load impedance of 50 ohms is connected to the output terminal 122 and the load impedance of the output terminal 122 viewed from the input terminal 121 becomes 20 ohms.

[0053] like Figure 3 As shown, the load impedance starts from the output terminal 122 and transitions to a capacitive part through the capacitor 124, and then transitions to the vicinity of the real part through the inductor 1231. Then, the load impedance transitions to 1 / n through the action of the 1:n ideal balanced-unbalanced transformer. 2 Then, it transitions to inductance through inductor 1251 and further transitions to inductance through inductor 1252. Then, the load impedance returns to the vicinity of the real part through the resonant circuit 126.

[0054] The resonance circuit 126 is a series resonance circuit including an inductor and a capacitor, and makes the load impedance of the second harmonic close to zero.

[0055] Furthermore, the circuit formed by the inductor 123 and the capacitor 124 makes the load impedance of the third harmonic viewed from the input terminal 121 to the output terminal 122 close to infinity.

[0056] As a result, the power amplifier circuit 100 operates close to class F without affecting the fundamental frequency, and thus the power efficiency can be improved.

[0057] <Power Amplifier Circuit 200 According to Second Embodiment>

[0058] Figure 4 1 is a diagram showing an example of the structure of the power amplifier circuit 200 involved in the second embodiment. In addition, the power amplifier circuit 200 involved in the second embodiment omits the description of the matters common to the power amplifier circuit 100 involved in the first embodiment described above, and only the differences are described. In addition, the same effects based on the same structure will not be mentioned one by one. Regarding these, the same is also true in the power amplifier circuits 300, 400, 500, 600, 700, 800, and 900 involved in the subsequent embodiments.

[0059] like Figure 4As shown, the matching circuit 220 of the power amplifier circuit 200 is different from the matching circuit 120 in that a first resonant circuit 226 a , a switch 226 b , and a second resonant circuit 226 c are provided instead of the resonant circuit 126 .

[0060] The first resonance circuit 226a is, for example, a series resonance circuit, and makes the load impedance with respect to the second harmonic of the fundamental frequency close to zero.

[0061] The switch 226b is connected in series with the first resonant circuit 226a.

[0062] The second resonant circuit 226c is connected in parallel with the first resonant circuit 226a and the switch 226b. The second resonant circuit 226c is, for example, a series resonant circuit, and makes the load impedance with respect to the second harmonic of a frequency different from the fundamental frequency close to zero.

[0063] When the switch 226b is off, the matching circuit 220 makes the load impedance of the second harmonic when the output terminal 222 is viewed from the input terminal 221 close to zero in a given frequency band. On the other hand, when the switch 226b is on, the matching circuit 220 makes the load impedance of the second harmonic when the output terminal 222 is viewed from the input terminal 221 close to zero in a frequency band different from the given frequency band.

[0064] Thus, the matching circuit 220 can widen the bandwidth of the power amplifier circuit 200 .

[0065] <Power Amplifier Circuit 300 According to Third Embodiment>

[0066] Figure 5 It is a diagram showing an example of the configuration of a power amplifier circuit 300 according to the third embodiment.

[0067] like Figure 5 As shown, the matching circuit 320 of the power amplifier circuit 300 is provided with a resonant circuit 326a, a capacitor 326b connected in parallel with the resonant circuit 326a, an inductor 326c, and a switch 326d, compared with the matching circuit 120.

[0068] The resonant circuit 326a is, for example, a series resonant circuit, which makes the load impedance of the second harmonic close to zero.

[0069] The capacitor 326b, the inductor 326c, and the switch 326d are connected in series.

[0070] The inductor 326c is preferably configured to perform magnetic field coupling with at least one of the inductor 323 and the inductor 325. In this case, when the switch 326d is turned on, a current flows through the inductor 326c, and the inductance value of the inductor 323 or the inductor 325 that performs magnetic field coupling increases or decreases. As a result, the matching circuit 320 can adjust the load impedance when the output terminal 322 is viewed from the input terminal 321 at the fundamental frequency. Furthermore, in the case where the load impedance changes due to the on / off of the switch 326d and the load impedance of the second harmonic is generated, adjustment based on magnetic field coupling can be performed.

[0071] <Power Amplifier Circuit 400 According to Fourth Embodiment>

[0072] Figure 6 It is a diagram showing an example of the configuration of a power amplifier circuit 400 according to the fourth embodiment.

[0073] like Figure 6 As shown, the matching circuit 420 of the power amplifier circuit 400 is compared with the matching circuit 320, and the resonant circuit 326a includes a capacitor 426a, an inductor 426b, and a switch 426c.

[0074] The inductor 426b is preferably arranged to be magnetically coupled with at least one of the inductor 423 and the inductor 425. In this case, when the switch 426c is turned on, a current flows through the inductor 426b, and the inductance value of the inductor 423 or the inductor 425 that is magnetically coupled increases or decreases.

[0075] Thus, by turning on and off the switch 426c, the value of the load impedance at the fundamental frequency when the output terminal 422 is viewed from the input terminal 421 can be selectively adjusted. That is, by the inductor 426b that is magnetically coupled with at least one of the inductor 423 or the inductor 425, the load impedance of the second harmonic can be made close to zero, and the impedance of the fundamental frequency can also be adjusted at the same time.

[0076] <Power Amplifier Circuit 500 According to Fifth Embodiment>

[0077] Figure 7 It is a diagram showing an example of the configuration of a power amplifier circuit 500 according to the fifth embodiment.

[0078] like Figure 7 As shown, the matching circuit 520 of the power amplifier circuit 500 includes a capacitor 526a, inductors 526b and 526d, and a switch 526c instead of the resonant circuit 126, compared with the matching circuit 120.

[0079] One end of the capacitor 526 a is connected to the input terminal 521 of the matching circuit 520 .

[0080] One end of the inductor 526 b is connected to the other end of the capacitor 526 a , and the other end of the inductor 526 b is connected to the switch 526 c .

[0081] One end of the switch 526 c is connected to the other end of the inductor 526 b , and the other end of the switch 526 c is connected to the ground 527 .

[0082] One end of the inductor 526d is connected to the other end of the capacitor 526a, and the other end is connected to the ground 527. That is, the inductor 526d is connected in parallel with the inductor 526b and the switch 526c.

[0083] When the switch 526c is off, the matching circuit 520 makes the load impedance of the second harmonic when the output terminal 522 is viewed from the input terminal 521 close to zero in a given frequency band. On the other hand, when the switch 526c is on, the matching circuit 520 makes the load impedance of the second harmonic when the output terminal 522 is viewed from the input terminal 521 close to zero in a frequency band different from the given frequency band.

[0084] Thus, the matching circuit 520 can widen the bandwidth of the power amplifier circuit 500 .

[0085] <Power Amplifier Circuit 600 According to Sixth Embodiment>

[0086] Figure 8 It is a diagram showing an example of the configuration of a power amplifier circuit 600 according to the sixth embodiment.

[0087] like Figure 8 As shown, the matching circuit 620 of the power amplifier circuit 600 is compared with the resonant circuit 526 of the matching circuit 520, and the capacitor 526a is replaced by the inductor 626a, and the inductors 526b and 526d are replaced by capacitors 626b and 626d.

[0088] Thus, similarly to the power amplifier circuit 500 according to the fifth embodiment, the matching circuit 620 can widen the bandwidth of the power amplifier circuit 600 .

[0089] <Power Amplifier Circuit 700 According to Seventh Embodiment>

[0090] Fig. 9 It is a diagram showing an example of the configuration of a power amplifier circuit 700 according to the seventh embodiment.

[0091] like Fig. 9As shown, the power amplifier circuit 700 is compared with the power amplifier circuits 100, 200, 300, 400, 500, and 600, in that the emitter and collector of the power amplifier 710 are connected via a series resonant circuit 711 including an inductor 711a and a capacitor 711b. The emitter of the power amplifier 710 and the series resonant circuit 711 are connected to a common ground 713. Here, the series resonant circuit 711 is formed on a semiconductor substrate 730 together with the power amplifier 710, for example.

[0092] An example of the connection relationship of each element is specifically described. One end of the inductor 711a is connected to the collector of the power amplifier 710, and the other end of the inductor 711a is connected to one end of the capacitor 711b. The other end of the capacitor 711b is connected to the emitter of the power amplifier 710. The emitter of the power amplifier 710 and the other end of the capacitor 711b are connected to the ground 713.

[0093] In addition, Fig. 9 As an example, the capacitor 726a, the inductor 726b, and the switch 726c of the resonant circuit 726 of the matching circuit 720 are connected in series, but the present invention is not limited to this. For example, Figure 1 , Figures 4 to 8 Resonant circuits 126, 226, 326, 426, 526, 626 are shown.

[0094] In the power amplifier circuit 700 according to the seventh embodiment, the load impedance of the second harmonic when the output terminal 722 is viewed from the input terminal 721 is close to zero in a given frequency band when the switch 726c is turned off, by the series resonant circuit 711. On the other hand, in the power amplifier circuit 700, when the switch 726c is turned on, the load impedance of the second harmonic when the output terminal 722 is viewed from the input terminal 721 is close to zero in a frequency band different from the given frequency band. That is, in the power amplifier circuit 700, the load impedance can be close to zero in two frequency bands.

[0095] Furthermore, by connecting the series resonant circuit 711 and the emitter of the power amplifier 710 to the ground 713, the capacitance of the capacitor 711b can be increased even when the operating frequency of the power amplifier circuit 700 is high. This is because by connecting the series resonant circuit 711 and the emitter of the power amplifier 710 to the ground 713, the influence of the parasitic inductance generated between the ground 727 and the ground 713 can be eliminated.

[0096] Regarding the issues when the operation frequency is high, specifically, Figure 7 The power amplifier circuit 500 shown in FIG. Figure 7As shown in FIG. 1 , a parasitic inductor is connected between the ground 527 of the resonance circuit 526 and the ground connected to the emitter of the power amplifier 510 due to the routing of the wiring on the substrate. Therefore, when the operating frequency of the power amplifier circuit 500 is high, the capacitance of the capacitor 526a must be reduced due to the parasitic inductor. As a result, the frequency band of the frequency at which the impedance of the second harmonic is reduced can be narrowed.

[0097] <Power Amplifier Circuit 800 According to Eighth Embodiment>

[0098] Fig.10 It is a diagram showing an example of the configuration of a power amplifier circuit 800 according to the eighth embodiment.

[0099] like Fig.10 As shown, the power amplifier circuit 800 and Fig. 9 Compared with the power amplifier circuit 700 shown in the figure, the inductor 811a of the series resonant circuit 811 and the inductor 826a of the resonant circuit 826 are configured to perform magnetic field coupling.

[0100] In the power amplifier circuit 800 according to the eighth embodiment, the inductance value of the inductor 811a can be increased or decreased by turning on and off the switch 826c of the resonance circuit 826. Thus, the resonance frequency of the series resonance circuit 811 of the inductor 811a and the capacitor 811b on the substrate 830 can be adjusted.

[0101] <Power Amplifier Circuit 900 According to Ninth Embodiment>

[0102] Fig.11 It is a diagram showing an example of the configuration of a power amplifier circuit 900 according to the ninth embodiment.

[0103] like Fig.11 As shown, the power amplifier circuit 900 and Figure 1 Compared with the power amplifier circuit 100 shown in the figure, a DC power supply terminal 941 for supplying power to the power amplifier 910 is provided.

[0104] Specifically, the DC power supply terminal 941 is connected to the ground 944 via a parallel capacitor 942 for removing high-frequency components. The DC power supply terminal 941 is connected to one end of a capacitor 928 for DC blocking via an inductor 943. One end of the capacitor 928 is connected to the input terminal 921. In addition, the capacitor 928 is connected in series with the inductor 923 and the inductor 925, and the inductor 923 and the inductor 925 correspond to the inductor 123 and the inductor 125 of the first embodiment. In addition, in the power amplifier circuit 900 according to the ninth embodiment, the given potential 927 connected to the resonance circuit 926 is the ground.

[0105] Here, in Fig.11 , the resonant circuit 926 in the power amplifier circuit 900 according to the ninth embodiment is shown. Figure 1 The resonant circuit 126 has the same structure, but is not limited to this. For example, the resonant circuit 926 may also be Figures 4 to 8 The resonant circuits 426, 526, 626, 726, and 826 shown in the figure also achieve the same effect.

[0106] <Power Amplifier Circuit 1000 According to Tenth Embodiment>

[0107] Reference Fig.12 , the structure of the power amplifier circuit 1000 involved in the tenth embodiment is described. Fig.12 10 is a diagram showing an example of the configuration of a power amplifier circuit 1000 according to the tenth embodiment.

[0108] like Fig.12 As shown, the power amplifier circuit 1000 and Figure 1 Compared with the power amplifier circuit 100 shown in FIG. 1 , the power amplifier circuit 1000 includes a power amplifier of a driving stage (hereinafter referred to as a "driving amplifier 1010") and a power amplifier of an output stage (hereinafter referred to as an "output amplifier 1011"), and a matching circuit 1020 is provided between the driving amplifier 1010 and the output amplifier 1011. In addition, the matching circuit 1020 is configured to make the load impedance in the second harmonic close to infinity, compared with the matching circuit 120 of the power amplifier circuit 100. The power amplifier circuit 1000 includes a capacitor 1030 between the driving amplifier 1010 and the matching circuit 1020, for example. The capacitor 1030 blocks a DC component, for example. In addition, the capacitor 1030 can adjust the fundamental wave component of the load impedance of the driving amplifier 1010, for example.

[0109] like Fig.12 As shown, the matching circuit 1020 includes an input terminal 1021 to which an RF signal obtained by amplifying the input signal RFin from the driver amplifier 1010 is input, and an output terminal 1022 to output the output signal RFout to the output amplifier 1011. The matching circuit 1020 includes, for example, an inductor 1023 and a capacitor 1024 connected in parallel with the inductor 1023, one end of the inductor 1023 is connected to the input terminal 1021, and the other end is connected to the output terminal 1022. The matching circuit 1020 is configured to make the load impedance of the second harmonic, for example, close to infinity by the inductor 1023 and the capacitor 1024. In this embodiment, the load impedance of the second harmonic is made infinite by the inductor 1023 and the capacitor 1024, but the load impedance of the n-th harmonic (n: a natural number greater than 2) may also be made infinite.

[0110] In addition, the matching circuit 1020 includes, for example, an inductor 1025, one end of which is connected to the output terminal 1022, and the other end of which is connected to the ground 1026. Here, the inductor 1025 is preferably arranged to perform magnetic field coupling with the inductor 1023, for example. Thus, the matching circuit 1020 can adjust the load impedance in the frequency band of the fundamental wave, for example.

[0111] Next, refer to Fig.13 , an overview of the load impedance in the fundamental wave frequency band and the second harmonic frequency band viewed from the driver amplifier 1010 is described. Fig.13 is a Smith chart showing an example of load impedance with respect to frequency changes observed from the driver amplifier 1010. Fig.13 In FIG. 1 , the thick dotted line shows the shift of the load impedance in the frequency band of the fundamental wave, and the thick solid line shows the shift of the load impedance in the frequency band of the second harmonic.

[0112] exist Fig.13 , it is shown that the broadband is achieved in region R1 on the Smith chart of the fundamental frequency band. Fig.13 , a case where the load impedance is close to infinity in region R2 on the Smith chart of the frequency band of the second harmonic is shown. Here, the so-called load impedance in region R2 is close to infinity, for example, refers to a load impedance that is more than twice the load impedance in region R1. In this way, the power amplifier circuit 1000 involved in the tenth embodiment can widen the load impedance in the frequency band of the fundamental wave through the balanced-unbalanced transformer formed by the inductor 1023 and the inductor 1025. In addition, the power amplifier circuit 1000 involved in the tenth embodiment makes the load impedance close to infinity in the frequency band of the second harmonic through the parallel resonant circuit formed by the inductor 1023 and the capacitor 1024. As a result, the power amplifier circuit 1000 can improve its efficiency.

[0113] <Function of Matching Circuit 1020>

[0114] Next, refer to Fig.14 , Fig.15 , the function of the matching circuit 1020 for widening the load impedance in the fundamental wave frequency band will be described in detail. Fig.14 It is a diagram showing an equivalent circuit of the matching circuit 1020 according to the tenth embodiment. Fig.15 1 is a Smith chart showing an example of the shift of the load impedance in the fundamental wave frequency band of the matching circuit 1020 according to the tenth embodiment.

[0115] Fig.12 The matching circuit 1020 shown can be used as Fig.14 The equivalent circuit shown is shown. Fig.14 For convenience, the inductance of the inductor 1023 is set to "L1", the inductance of the inductor 1025 is set to "L2", the coupling coefficient between the inductor 1023 and the inductor 1025 is set to "k", and the base ballast capacitor of the output amplifier 1011 is set to "C bb ”, the capacitance of the capacitor 1024 is set to “C2”, and the capacitance of the capacitor 1030 is set to “C1”, and the following description is made. Fig.14 In the example, an equivalent circuit is shown in the case where the inductance value of the inductor 1025 is small in the matching circuit 1020, and the impedance of the inductor 1025 viewed from the output terminal 1022 is sufficiently small compared to the impedance of the output amplifier 1011 viewed from the output terminal 1022 and the impedance of the inductor 1023 viewed from the output terminal 1022. Based on this equivalent circuit, refer to Fig.15 The operation of the load impedance viewed from the driver amplifier 1010 in the frequency band of the fundamental wave will be described.

[0116] exist Fig.15 In the order of the frequencies in the fundamental wave from low to high, the frequencies are set as frequency f1, frequency f2, frequency f3, frequency f4, and frequency f5. Fig.15 For the sake of convenience, the shift of load impedance caused by "C1" and "C2" is omitted, and the effect of the 1:n balanced-unbalanced transformer is ignored.

[0117] First, the movement of the load impedance at the frequency f1 is described. Fig.15 As shown, the load impedance starts from point O. bb " transitions to point f11 due to the capacitive property of (1-k)·L1 in series, returns to point f12 due to the capacitive property of k·L1 in parallel, and transitions to point f14 due to the inductance of (1-k)·L2 in series. Similarly, the load impedances of frequencies f2 to f5 start from point O, transition from point f21 to point f24, from point f31 to point f34, from point f41 to point f44, and from point f51 to point f54. Fig.15 If points f14 to f54 are connected in sequence, the load impedance is shown to be gathered on the Smith chart. Fig.15 As shown in FIG. 1 , by connecting points f14 to f54 in sequence to form a winding on the Smith chart, the load impedance becomes constant at the frequencies shown by f24 to f54. The power amplifier shows a broadband power characteristic when the frequency dependence of its output load impedance is small. Fig.15As shown in FIG. 1 , the load impedance is made constant, thereby enabling the operation of a broadband power amplifier. Fig.15 In the power amplifier circuit 1000, the load impedance viewed from the driver amplifier 1010 is widened in the frequency band of the fundamental wave.

[0118] <<First Modification>>

[0119] Reference Fig.16 , the structure of a first variation of the power amplifier circuit 1000 according to the tenth embodiment will be described. Fig.16 FIG. 1 is a diagram showing an example of a structure of a first variation of the power amplifier circuit 1000 according to the tenth embodiment. Fig.16 As shown, the matching circuit 1020a of the power amplifier circuit 1000a according to the first modification example is Fig.12 Compared with the matching circuit 1020 of the power amplifier circuit 1000 shown in FIG. 1 , a plurality of capacitors 1024a are connected in parallel with the inductor 1023. A switch 1024b is connected in series to each capacitor 1024a. Thus, the resonance frequency of the parallel resonance circuit formed by the inductor 1023 and the capacitor 1024a can be adjusted.

[0120] <<Second Modification>>

[0121] Reference Fig.17 , the structure of a second variation of the power amplifier circuit 1000 according to the tenth embodiment will be described. Fig.17 FIG. 1 is a diagram showing an example of a structure of a second variation of the power amplifier circuit 1000 according to the tenth embodiment. Fig.17 As shown, the matching circuit 1020b of the power amplifier circuit 1000b according to the second modification example is Fig.12 Compared with the matching circuit 1020 of the power amplifier circuit 1000 shown in the figure, a resonant circuit 1027 is provided, one end of which is connected to the collector (output terminal) of the driver amplifier 1010, and the other end is connected to the ground 1028. The resonant circuit 1027 is, for example, a series resonant circuit formed by a capacitor and an inductor, and makes the load impedance of the third harmonic close to zero. Thus, the efficiency of the power amplifier circuit 1000b can be improved. In addition, although it corresponds to the third harmonic in the second modification, it can also be set to the nth harmonic.

[0122] Summary

[0123] The matching circuit 120 of the power amplifier circuit 100 according to the exemplary embodiment of the present disclosure includes: an input terminal 121 to which an amplified signal is input from the power amplifier 110; an output terminal 122; an inductor 123 (first inductor) having one end connected to the input terminal 121 and the other end connected to the output terminal 122; a capacitor 124 (first capacitor) connected in parallel to the inductor 123 (first inductor); an inductor 125 (second inductor) having one end connected to the input terminal 121 and the other end connected to a given potential 127 (ground); and a resonant circuit 126 (first series resonant circuit) connected in parallel to the inductor 125 (second inductor). Thus, the matching circuit 120 can improve the efficiency of the power amplifier circuit 100.

[0124] In the matching circuit 120 of the power amplifier circuit 100, the predetermined potential 127 (ground) connected to the other end of the inductor 125 (second inductor) is different from the power supply supplied to the power amplifier 110. Thus, the matching circuit 120 can improve the efficiency of the power amplifier circuit 100.

[0125] In the matching circuit 120 of the power amplifier circuit 100, a predetermined potential 127 (ground) connected to the other end of the inductor 125 (second inductor) is a power supply supplied to the power amplifier 110. Thus, the matching circuit 920 can improve the efficiency of the power amplifier circuit 900.

[0126] Furthermore, the resonant circuit 226 (first series resonant circuit) of the matching circuit 220 of the power amplifier circuit 200 includes a first resonant circuit 226a (second series resonant circuit), a switch 226b (first switch) connected in series with the first resonant circuit 226a (second series resonant circuit), and a second resonant circuit 226c (third series resonant circuit) connected in parallel with the first resonant circuit 226a (second series resonant circuit) and the switch 226b (first switch). Thus, the matching circuit 220 can widen the power amplifier circuit 200.

[0127] In addition, the resonant circuit (resonant circuit corresponding to the first resonant circuit 226a) (second series resonant circuit) of the matching circuit 320 of the power amplifier circuit 300 includes a capacitor 326b (first capacitor) and an inductor 326c (third inductor) connected in series with the capacitor 326b (first capacitor). Thus, the matching circuit 320 can adjust the load impedance when the output terminal 322 is viewed from the input terminal 321 at the fundamental frequency, thereby improving the efficiency of the power amplifier circuit 300.

[0128] In addition, the resonant circuit (with Figure 5The resonant circuit corresponding to the second resonant circuit 226c (the third series resonant circuit) includes a capacitor 426a (the second capacitor), a switch 426c (the second switch) connected in series with the capacitor 426a (the second capacitor), and an inductor 426b (the fourth inductor) connected in series with the switch 426c (the second switch). Thus, by turning the switch 426c on and off, the value of the load impedance at the fundamental frequency when the output terminal 422 is viewed from the input terminal 421 can be selectively adjusted, thereby improving the efficiency of the power amplifier circuit 400.

[0129] Furthermore, the resonant circuit 526 (first series resonant circuit) of the matching circuit 520 of the power amplifier circuit 500 includes a capacitor 526a (third capacitor), an inductor 526b (fifth inductor) connected in series with the capacitor 526a (third capacitor), a switch 526c (third switch) connected in series with the inductor 526b (fifth inductor), and an inductor 526d (sixth inductor) connected in parallel with the inductor 526b (fifth inductor) and the switch 526c (third switch). Thus, the matching circuit 520 can widen the bandwidth of the power amplifier circuit 500.

[0130] Furthermore, the resonant circuit 626 (first series resonant circuit) of the matching circuit 620 of the power amplifier circuit 600 includes an inductor 626a (seventh inductor), a capacitor 626b (fourth capacitor) connected in series with the inductor 626a (seventh inductor), a switch 626c (fourth switch) connected in series with the capacitor 626b (fourth capacitor), and a capacitor 626d (fifth capacitor) connected in parallel with the capacitor 626b (fourth capacitor) and the switch 626c (fourth switch). Thus, the matching circuit 620 can widen the power amplifier circuit 600.

[0131] In addition, the power amplifier circuit 700 includes: a matching circuit 720; a power amplifier 710; and a series resonant circuit 711 (fourth series resonant circuit), one end of which is connected to an output terminal 722 of the power amplifier 710, and the other end of which is connected to a ground 713 (ground). Thus, even when the operating frequency of the power amplifier circuit 700 is high, the capacitance of the capacitor 711b of the series resonant circuit 711 can be increased.

[0132] In the power amplifier circuit 800, the series resonant circuit 811 (the fourth series resonant circuit) includes an inductor 811a (the eighth inductor) and a capacitor 811b (the fifth capacitor) connected in series with the inductor 811a (the eighth inductor), and the resonant circuit 826 (the first series resonant circuit) includes an inductor 826a (the ninth inductor) that performs magnetic field coupling with the inductor 811a (the eighth inductor). Thus, the resonant frequency of the series resonant circuit 811 including the inductor 811a and the capacitor 811b on the substrate 830 on which the power amplifier 810 is arranged can be adjusted.

[0133] Furthermore, the matching circuit 1020 is provided between the driver amplifier 1010 (first power amplifier) ​​and the output amplifier 1011 (second power amplifier), and includes: an input terminal 1021 to which an amplified signal is input from the driver amplifier 1010 (first power amplifier); an output terminal 1022; an inductor 1023 (a tenth inductor) having one end connected to the input terminal 1021 and the other end connected to the output terminal 1022; a capacitor 1024 (a sixth capacitor) connected in parallel to the inductor 1023 (the tenth inductor); and an inductor 1025 (an eleventh inductor) having one end connected to the output terminal 1022 and the other end connected to the ground 1026. Thus, the load impedance can be widened in the frequency band of the fundamental wave, and the load impedance can be made close to infinity in the frequency band of the second harmonic, so that the efficiency of the power amplifier circuit 1000 can be improved.

[0134] Furthermore, in the matching circuit 1020a, the capacitor 1024a (sixth capacitor) includes a plurality of capacitors, and further includes a switch 1024b (fifth switch) connected in series to each of the plurality of capacitors in the capacitor 1024a (sixth capacitor). Thus, the resonance frequency of the parallel resonance circuit formed by the inductor 1023 and the capacitor 1024a can be adjusted.

[0135] Furthermore, the matching circuit 1020b further includes a resonant circuit 1027 (fifth series resonant circuit), one end of which is connected to the output terminal of the driver amplifier 1010 (first power amplifier), and the other end of which is connected to the ground 1028. Thus, the load impedance of the third harmonic can be made close to zero, and thus the efficiency of the power amplifier circuit 1000b can be improved.

[0136] Furthermore, the power amplifier circuit 1000 includes a matching circuit 1020, a driver amplifier 1010 (first power amplifier), an output amplifier 1011 (second power amplifier), and a capacitor 1030 (seventh capacitor) provided between the matching circuit 1020 and the driver amplifier 1010 (first power amplifier). Thus, the load impedance can be widened in the frequency band of the fundamental wave, and the load impedance can be made close to infinity in the frequency band of the second harmonic.

[0137] The above-described embodiments are used to make the present disclosure easy to understand and are not used to limit the interpretation of the present disclosure. The present disclosure can be changed or improved without departing from its main purpose, and the present disclosure also includes its equivalents. That is, the embodiments in which the technical personnel in the field appropriately apply design changes to the embodiments are also included in the scope of the present disclosure as long as they have the characteristics of the present disclosure. The elements and their configurations etc. possessed by the embodiments are not limited to the illustrated elements and their configurations, and can be appropriately changed.

Claims

1. A matching circuit comprising: An input terminal to which an amplified signal is input from a power amplifier; Output terminals; a first inductor, one end of which is connected to the input terminal, and the other end of which is connected to the output terminal; a first capacitor connected in parallel with the first inductor; a second inductor having one end connected to the input terminal and the other end connected to the ground; as well as a first series resonant circuit connected in parallel with the second inductor, The first inductor and the second inductor are electromagnetically coupled.

2. The matching circuit according to claim 1, wherein: The ground connected to the other end of the second inductor is different from a power supply supplied to the power amplifier.

3. The matching circuit according to claim 1, wherein: The ground connected to the other end of the second inductor serves as a power supply supplied to the power amplifier.

4. The matching circuit according to any one of claims 1 to 3, wherein: The first series resonant circuit has: A second series resonant circuit; a first switch connected in series with the second series resonant circuit; and The third series resonant circuit is connected in parallel with the second series resonant circuit and the first switch.

5. The matching circuit according to claim 4, wherein: The second series resonant circuit has: a first capacitor; and The third inductor is connected in series with the first capacitor.

6. The matching circuit according to claim 4, wherein: The third series resonant circuit has: The second capacitor; a second switch connected in series with the second capacitor; and The fourth inductor is connected in series with the second switch.

7. The matching circuit according to any one of claims 1 to 3, wherein: The first series resonant circuit has: The third capacitor; a fifth inductor connected in series with the third capacitor; a third switch connected in series with the fifth inductor; and The sixth inductor is connected in parallel with the fifth inductor and the third switch.

8. The matching circuit according to any one of claims 1 to 3, wherein: The first series resonant circuit has: 7th inductor; a fourth capacitor connected in series with the seventh inductor; a fourth switch connected in series with the fourth capacitor; as well as The fifth capacitor is connected in parallel with the fourth capacitor and the fourth switch.

9. A power amplifier circuit, comprising: The matching circuit according to any one of claims 1 to 8; the power amplifier; and The fourth series resonant circuit has one end connected to the output terminal of the power amplifier and the other end connected to the ground.

10. The power amplifier circuit according to claim 9, wherein: The fourth series resonant circuit has: 8th inductor; as well as a fifth capacitor connected in series with the eighth inductor, The first series resonant circuit includes a ninth inductor that is magnetically coupled to the eighth inductor.

11. A matching circuit, arranged between a first power amplifier and a second power amplifier, wherein: have: an input terminal to which an amplified signal is input from the first power amplifier; Output terminals; a tenth inductor, one end of which is connected to the input terminal, and the other end of which is connected to the output terminal; a sixth capacitor connected in parallel with the tenth inductor; and an eleventh inductor having one end connected to the output terminal and the other end connected to ground, The tenth inductor and the eleventh inductor are electromagnetically coupled.

12. The matching circuit according to claim 11, wherein: The sixth capacitor includes a plurality of capacitors, The matching circuit further includes a fifth switch connected in series to each of the plurality of capacitors in the sixth capacitor.

13. The matching circuit according to claim 11 or claim 12, wherein: The matching circuit further includes a fifth series resonant circuit having one end connected to the output terminal of the first power amplifier and the other end connected to the ground.

14. A power amplifier circuit comprising: The matching circuit according to any one of claims 11 to 13; The first power amplifier; the second power amplifier; and The seventh capacitor is provided between the matching circuit and the first power amplifier.

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