Amplification circuit

Abstract

Provided is an amplifier circuit capable of improving power efficiency and suppressing signal distortion. The amplifier circuit includes: a carrier amplifier connected between a signal input terminal and a signal output terminal; a peak amplifier connected between the signal input terminal and the signal output terminal; a phase shift line connected between the carrier amplifier and the signal output terminal; an auxiliary amplifier connected between the signal input terminal and the input terminal of the carrier amplifier; and a phase shift line connected between the signal input terminal and the input terminal of the carrier amplifier, and configured to invert the phase of the output signal of the auxiliary amplifier at the signal output terminal with respect to the phase of the output signal of the peak amplifier at the signal output terminal.

Description

Technical Field

[0001] The invention relates to an amplifier circuit. Background Art

[0002] Patent document 1 discloses a Doherty amplifier circuit having a carrier amplifier and a peak amplifier. In the Doherty amplifier circuit, when the power level of the input signal increases, the peak amplifier operates to adjust the load impedance at the output end of the carrier amplifier. As a result, the efficiency and linearity of the Doherty amplifier circuit are improved.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-127568 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the case of the Doherty amplifier circuit, when the peak amplifier operates, the carrier amplifier outputs a composite output signal of the carrier amplifier and the peak amplifier. However, there is a case where, due to the imperfect load impedance at the output end of the carrier amplifier, a portion of the output signal of the peak amplifier is not synthesized with the output signal of the carrier amplifier but leaks to the output terminal of the Doherty amplifier circuit alone. As a result, the power efficiency of the Doherty amplifier circuit is sometimes degraded, and the linearity of the gain is degraded, thereby generating signal distortion.

[0008] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a Doherty-type amplifier circuit capable of improving power efficiency and suppressing signal distortion.

[0009] Solutions for solving problems

[0010] In order to achieve the above-mentioned purpose, an amplifier circuit involved in one embodiment of the present invention comprises: an input terminal and an output terminal; a carrier amplifier, which is connected between the input terminal and the output terminal; a peak amplifier, which is connected between the input terminal and the output terminal; a first phase shift circuit, which is connected between the carrier amplifier and the output terminal, or between the peak amplifier and the output terminal; an auxiliary amplifier, which is connected between the input terminal and the input end or the output end of the carrier amplifier; and a second phase shift circuit, which is connected between the input terminal and the input end or the output end of the carrier amplifier, and is configured to invert the phase of the output signal of the auxiliary amplifier at the output terminal relative to the phase of the output signal of the peak amplifier at the output terminal.

[0011] In addition, an amplifier circuit involved in one embodiment of the present invention comprises: an input terminal and an output terminal; a carrier amplifier connected between the input terminal and the output terminal; a peak amplifier connected between the input terminal and the output terminal; a first phase shift circuit connected between the output end of the carrier amplifier and the output terminal; an auxiliary amplifier connected between the input terminal and the input end of the carrier amplifier; and a second phase shift circuit connected between the connection point between the input terminal and the output end of the auxiliary amplifier and the input end of the carrier amplifier.

[0012] In addition, an amplifier circuit involved in one embodiment of the present invention comprises: an input terminal and an output terminal; a carrier amplifier, which is connected between the input terminal and the output terminal; a peak amplifier, which is connected between the input terminal and the output terminal; a first phase shifting circuit and a second phase shifting circuit; an auxiliary amplifier, which is connected between the input terminal and the input end of the carrier amplifier; and a transformer, which has an input side coil and an output side coil, wherein one end of the first phase shifting circuit is connected to the output end of the peak amplifier, one end of the input side coil is connected to the output end of the carrier amplifier, the other end of the input side coil is connected to the other end of the first phase shifting circuit, one end of the output side coil is connected to the output terminal, the other end of the output side coil is connected to the ground, one end of the second phase shifting circuit is connected to the connection point between the input terminal and the output end of the auxiliary amplifier, and the other end of the second phase shifting circuit is connected to the input end of the carrier amplifier.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a Doherty-type amplifier circuit capable of improving power efficiency and suppressing signal distortion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a circuit configuration diagram of the amplifier circuit, high-frequency circuit, and communication device involved in Example 1.

[0016] Figure 2 is a circuit configuration diagram of an amplifier circuit according to a comparative example.

[0017] Figure 3 It is a graph schematically showing the gain and load impedance characteristics of the amplifier circuits according to the embodiment and the comparative example.

[0018] Figure 4 It is a circuit configuration diagram of an amplifier circuit, a high-frequency circuit, and a communication device according to the second embodiment.

[0019] Figure 5 It is a circuit structure diagram of the amplifier circuit involved in Example 3.

[0020] Figure 6 It is a circuit structure diagram of the amplifier circuit involved in Example 4.

[0021] Figure 7 This is a circuit configuration diagram of the amplifier circuit involved in Example 5. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention in detail. In addition, the embodiments described below all represent general or specific examples. The numerical values, shapes, materials, structural elements, configurations of structural elements, and connection methods shown in the following embodiments are examples, and their main purpose is not to limit the present invention. Regarding the structural elements in the following embodiments and modifications that are not recorded in the independent claims, they are described as arbitrary structural elements. In addition, the size or size ratio of the structural elements shown in the drawings is not necessarily strict. In each figure, the same figure mark is marked for substantially the same structure, and repeated descriptions are sometimes omitted or simplified.

[0023] In the following, terms such as parallel and perpendicular that indicate the relationship between elements, terms such as rectangular that indicate the shape of an element, and numerical ranges do not have strict meanings but also include substantially equivalent ranges, such as a difference of a few percent.

[0024] In the circuit structure of the present disclosure, "connection" includes not only direct connection using connection terminals and / or wiring conductors, but also electrical connection via other circuit elements. "Connection between A and B" means connection between A and B and both A and B, including series connection to the path connecting A and B, and also includes parallel connection (shunt connection) between the path and the ground.

[0025] In the present disclosure, a “signal path” refers to a transmission line composed of a wiring through which a high-frequency signal propagates, an electrode directly connected to the wiring, and a terminal directly connected to the wiring or the electrode.

[0026] In addition, in the circuit connection structure of the present disclosure, "component (element) A is arranged in series on path B" means that both the signal input end and the signal output end of component (element) A are connected to the wiring, electrode or terminal constituting path B. In addition, "a plurality of paths are connected in parallel" means that one end of each of the plurality of paths is connected to the same wiring, electrode or terminal.

[0027] (Implementation Method)

[0028] [1 Circuit Configurations of Amplifier Circuit 10, High-Frequency Circuit 1, and Communication Device 4 According to Embodiment 1]

[0029] Reference Figure 1 The circuit configurations of the amplifier circuit 10 , the high-frequency circuit 1 , and the communication device 4 according to Example 1 of the present embodiment will be described. Figure 1 1 is a circuit configuration diagram of the amplifier circuit 10 , the high-frequency circuit 1 , and the communication device 4 according to the first embodiment.

[0030] [1.1 Circuit Configuration of Communication Device 4]

[0031] First, the circuit structure of the communication device 4 is described. Figure 1 As shown, the communication device 4 according to the first embodiment includes a high-frequency circuit 1 , an antenna 2 , and an RF signal processing circuit (RFIC) 3 .

[0032] The high-frequency circuit 1 transmits a high-frequency signal between the antenna 2 and the RFIC 3. The detailed circuit structure of the high-frequency circuit 1 will be described later.

[0033] The antenna 2 is connected to the antenna connection terminal 100 of the high frequency circuit 1 , transmits the high frequency signal output from the high frequency circuit 1 , and receives a high frequency signal from the outside and outputs it to the high frequency circuit 1 .

[0034] RFIC 3 is an example of a signal processing circuit that processes a high-frequency signal, and is connected to the signal input terminal 120 and the signal output terminal 130 of the high-frequency circuit 1. Specifically, RFIC 3 performs signal processing on the reception signal input through the reception path of the high-frequency circuit 1 by down-conversion, etc., and outputs the reception signal generated after the signal processing to the baseband signal processing circuit (BBIC, not shown). In addition, RFIC 3 performs signal processing on the transmission signal input from the BBIC by up-conversion, etc., and outputs the transmission signal generated after the signal processing to the transmission path of the high-frequency circuit 1. In addition, RFIC 3 has a control unit that controls the circuit components of the high-frequency circuit 1. In addition, part or all of the functions of RFIC 3 as a control unit can also be installed outside RFIC 3, for example, it can also be installed on the BBIC or the high-frequency circuit 1.

[0035] In addition, RFIC 3 also has a function as a control unit that controls the power supply voltage and bias voltage (or bias current) provided to each amplifier of the high-frequency circuit 1. Specifically, RFIC 3 outputs a control signal to the high-frequency circuit 1. The power supply voltage and bias voltage (or bias current) controlled by the control signal are provided to each amplifier of the high-frequency circuit 1.

[0036] In addition, in the communication device 4 according to the present embodiment, the antenna 2 is not an essential component.

[0037] [1.2 Circuit structure of high frequency circuit 1]

[0038] Next, the circuit structure of the high frequency circuit 1 is described. Figure 1As shown, the high-frequency circuit 1 includes an amplifier circuit 10 , filters 61 and 62 , a low-noise amplifier 31 , a capacitor 71 , an inductor 72 , an antenna connection terminal 100 , a signal output terminal 110 , and a signal input terminal 120 .

[0039] The filter 61 is connected between the signal output terminal 110 and the antenna connection terminal 100, and allows the transmission signal of the frequency band A to pass among the transmission signals amplified by the amplifier circuit 10. The filter 62 is connected between the low noise amplifier 31 and the antenna connection terminal 100, and allows the signal of the reception band of the frequency band A among the reception signals received by the antenna 2 to pass.

[0040] In addition, the filters 61 and 62 may constitute a duplexer for transmitting and receiving signals in the frequency band A, or may be a filter for transmitting in a time division duplex (TDD) manner. When the filters 61 and 62 are filters for TDD, a switch for switching between transmission and reception is configured in at least one of the front stage and the rear stage of the filter.

[0041] The low noise amplifier 31 is connected between the filter 62 and the signal output terminal 130 , and amplifies the reception signal of the frequency band A and outputs the amplified signal to the RFIC 3 .

[0042] The capacitor 71 is a circuit element for impedance matching arranged in series between the signal output terminal 110 and the filter 61. The capacitor 71 may be connected (arranged in shunt) between the path connecting the signal output terminal 110 and the filter 61 and the ground, or may not be present.

[0043] The inductor 72 is a circuit element for impedance matching connected (disposed in shunt) between the path connecting the filter 61 and the antenna connection terminal 100 and the ground. The inductor 72 may be disposed in series between the filter 61 and the antenna connection terminal 100, or may not be provided.

[0044] In addition, the high-frequency circuit 1 may also include a transmission circuit that transmits a transmission signal of a frequency band B different from the frequency band A to the antenna 2, and a reception circuit that transmits a reception signal of the frequency band B received from the antenna 2 to the RFIC 3. Furthermore, the high-frequency circuit 1 may also constitute a circuit that transmits and receives high-frequency signals of three or more frequency bands.

[0045] [1.3 Circuit Structure of Amplifier Circuit 10 According to Embodiment 1]

[0046] Next, the circuit configuration of the amplifier circuit 10 will be described in detail.

[0047] like Figure 1As shown, the amplifier circuit 10 includes a signal input terminal 120 and a signal output terminal 110 , a carrier amplifier 11 , a peak amplifier 21 , an auxiliary amplifier 22 , phase shift lines 41 , 42 , and 43 , and a distributor 50 .

[0048] The signal input terminal 120 is an example of an input terminal, and is connected to the RFIC 3. The signal output terminal 110 is an example of an output terminal, and is connected to the antenna connection terminal 100 via the capacitor 71 and the filter 61. In addition, the signal input terminal 120, the signal output terminal 110, and the antenna connection terminal 100 can each be a metal conductor such as a metal electrode and a metal bump, or a point on a metal wiring.

[0049] The carrier amplifier 11 amplifies the high-frequency signal input to the carrier amplifier 11. The carrier amplifier 11 is, for example, a class A (or class AB) amplifier circuit that can amplify all power levels of the signal input to the carrier amplifier 11, and in particular, can perform efficient amplification in the low output region and the medium output region. The carrier amplifier 11 is, for example, an inverting amplifier that inverts the phase of the input signal and outputs it. The input end of the carrier amplifier 11 is connected to the signal input terminal 120 via the distributor 50, and the output end is connected to the signal output terminal 110 via the phase shift line 43.

[0050] The peak amplifier 21 amplifies the high-frequency signal input to the peak amplifier 21. The peak amplifier 21 is, for example, a class C amplifier circuit that can perform an amplification operation in a region where the power level of the signal input to the peak amplifier 21 is high. A bias voltage smaller than the bias voltage applied to the amplification transistor of the carrier amplifier 11 is applied to the amplification transistor of the peak amplifier 21. Accordingly, the higher the power level of the signal input to the peak amplifier 21, the lower the output impedance. Thus, the peak amplifier 21 can perform amplification operation with low distortion in a high output region. The peak amplifier 21 is, for example, an inverting amplifier that inverts the phase of the input signal and then outputs it. The input end of the peak amplifier 21 is connected to the signal input terminal 120 via the distributor 50 and the phase shift line 41, and the output end is connected to the signal output terminal 110.

[0051] The auxiliary amplifier 22 amplifies the high-frequency signal input to the auxiliary amplifier 22. The auxiliary amplifier 22 is, for example, a class C amplifier circuit that can perform an amplification operation in a region where the power level of the signal input to the auxiliary amplifier 22 is high. A bias voltage smaller than the bias voltage applied to the amplification transistor of the carrier amplifier 11 is applied to the amplification transistor of the auxiliary amplifier 22. Thus, the auxiliary amplifier 22 can perform a low-distortion amplification operation in a high-output region. The auxiliary amplifier 22 is, for example, an inverting amplifier that inverts the phase of the input signal and then outputs it. The input end of the auxiliary amplifier 22 is connected to the signal input terminal 120 via the distributor 50 and the phase shift line 41, and the output end is connected to the input end of the carrier amplifier 11 via the phase shift line 42.

[0052] Furthermore, it is desirable that the bias voltage supplied to the auxiliary amplifier 22 is equal to the bias voltage supplied to the peak amplifier 21. Furthermore, it is desirable that the power supply voltage supplied to the auxiliary amplifier 22 is equal to the power supply voltage supplied to the peak amplifier 21, and the operating point of the auxiliary amplifier 22 is equal to the operating point of the peak amplifier 21. Accordingly, the behavior of the output signal of the auxiliary amplifier 22 can be made the same as the behavior of the output signal of the peak amplifier 21.

[0053] The carrier amplifier 11, the peak amplifier 21, and the auxiliary amplifier 22 each include an amplifier transistor. The amplifier transistor is, for example, a bipolar transistor such as a heterojunction bipolar transistor (HBT) or a field effect transistor such as a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

[0054] Furthermore, the amplifier transistor of the auxiliary amplifier 22 may be formed in the formation region of the amplifier transistor of the peak amplifier 21. In addition, regarding the formation region of the amplifier transistor, for example, in the case where the amplifier transistor is a bipolar transistor, the formation region of the amplifier transistor is defined as a region where the base, emitter, and collector are formed. In addition, the amplifier transistor of the auxiliary amplifier 22 is formed in the formation region of the amplifier transistor of the peak amplifier 21, which means that at least one of the base, emitter, and collector of the amplifier transistor of the auxiliary amplifier 22 shares at least a part of the base, emitter, and collector of the amplifier transistor of the peak amplifier 21. Accordingly, from the viewpoint that the auxiliary amplifier 22 and the peak amplifier 21 share the formation region of the amplifier transistor, it can be said that the behavior of the output signal is the same, and a so-called pairing operation is performed.

[0055] The phase shift line 43 is an example of a first phase shift circuit, for example, a 1 / 4 wavelength transmission line, which delays the phase of a high-frequency signal input from one end by 90° (1 / 4 wavelength) and then outputs it from the other end. In addition, the phase shift line 43 (first phase shift circuit) may not have a phase shift line, for example, it may be an inductor arranged in series in a path connecting the carrier amplifier 11 and the signal output terminal 110, or a low-pass filter composed of an inductor and a capacitor. One end of the phase shift line 43 is connected to the output end of the carrier amplifier 11, and the other end is connected to the connection point between the output end of the peak amplifier 21 and the signal output terminal 110.

[0056] The phase shift line 41 is an example of a third phase shift circuit, for example, a 1 / 4 wavelength transmission line. The phase shift line 41 delays the phase of the high-frequency signal input from one end by 90° (1 / 4 wavelength) and outputs it from the other end. In addition, the phase shift line 41 (third phase shift circuit) may not have a phase shift line, for example, it may be an inductor arranged in series in the path connecting the distributor 50 with the peak amplifier 21 and the auxiliary amplifier 22, or a low-pass filter composed of an inductor and a capacitor. One end of the phase shift line 41 is connected to the signal input terminal 120 via the distributor 50, and the other end is connected to the input end of the peak amplifier 21 and the input end of the auxiliary amplifier 22.

[0057] The phase shift circuit 42 is an example of a fourth phase shift circuit, which makes the phase of the high-frequency signal input from one end thereof advance by 90° (1 / 4 wavelength) (or lag by 270°) and then output from the other end. In addition, the phase shift circuit 42 (fourth phase shift circuit) may not have such a phase shift circuit, for example, it may be a capacitor arranged in series in a path connecting the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11, or a high-pass filter composed of a capacitor and an inductor. One end of the phase shift circuit 42 is connected to the output end of the auxiliary amplifier 22, and the other end is connected to the input end of the carrier amplifier 11.

[0058] The phase shift lines 41 and 42 constitute a second phase shift circuit, and are connected between the signal input terminal 120 and the input end of the carrier amplifier 11. According to the above structure, the phase shift lines 41 and 42 (second phase shift circuit) can invert the phase of the output signal of the auxiliary amplifier 22 at the signal output terminal 110 relative to the phase of the output signal of the peak amplifier 21 at the signal output terminal 110.

[0059] In addition, each of the phase shift circuits 41 and 43 is not limited to a circuit that strictly lags the phase of the input high-frequency signal of the frequency band A by 90°, and any circuit can be used as long as the phase of the input high-frequency signal of the frequency band A is delayed within the range of (90°±20°). In addition, the phase shift circuit 42 is not limited to a circuit that strictly advances the phase of the input high-frequency signal of the frequency band A by 90°, and any circuit can be used as long as the phase of the input high-frequency signal of the frequency band A is advanced within the range of (90°±20°).

[0060] The distributor 50 is an example of a power distributor, and is connected between the signal input terminal 120 and the input end of the carrier amplifier 11, the input end of the peak amplifier 21, and the input end of the auxiliary amplifier 22. The distributor 50 has a first terminal, a second terminal, and a third terminal. The distributor 50 distributes the power of the high-frequency signal input to the first terminal at a predetermined distribution ratio, and outputs one side of the high-frequency signal obtained by the power distribution from the second terminal, and outputs the other side of the high-frequency signal obtained by the power distribution from the third terminal. The first terminal is connected to the signal input terminal 120, the second terminal is connected to the input end of the carrier amplifier 11, and the third terminal is connected to one end of the phase shift line 41.

[0061] Here, refer to Figure 2 The operation of a Doherty-type amplifier circuit including a carrier amplifier and a peak amplifier will be described with reference to the amplifier circuit 500 according to the comparative example shown.

[0062] The Doherty type amplifier circuit refers to an amplifier circuit that achieves high efficiency by using multiple amplifiers as carrier amplifiers and peak amplifiers. The carrier amplifier refers to an amplifier that operates regardless of whether the power of the high-frequency signal (input) is low or high in the Doherty type amplifier circuit. The peak amplifier refers to an amplifier that operates mainly when the power of the high-frequency signal (input) is high in the Doherty type amplifier circuit. Therefore, when the input power of the high-frequency signal is low, the high-frequency signal is mainly amplified by the carrier amplifier, and when the input power of the high-frequency signal is high, the high-frequency signal is amplified by the carrier amplifier and the peak amplifier and then synthesized. Through this action, in the Doherty type amplifier circuit, in the low output power region, the load impedance observed from the carrier amplifier increases, and the efficiency at low output power is improved. In addition, in the high output power region, the load impedance observed from the carrier amplifier decreases, and the linearity at high output power is improved.

[0063] Figure 21 is a circuit diagram of an amplifier circuit 500 according to a comparative example. The amplifier circuit 500 shown in the figure includes a signal input terminal 120 and a signal output terminal 110, a carrier amplifier 11, a peak amplifier 21, phase shift lines 41 and 43, and a distributor 50. The amplifier circuit 500 according to the comparative example is different in structure from the amplifier circuit 10 according to the first embodiment in that the auxiliary amplifier 22 and the phase shift line 42 are not provided.

[0064] First, the load impedance of the carrier amplifier 11 when the carrier amplifier 11 and the peak amplifier 21 are in operation (ON) (when a large signal is input) is impedance-converted by the phase shift line 43, thereby becoming smaller than the load impedance of the carrier amplifier 11 when the carrier amplifier 11 is in operation (ON) and the peak amplifier 21 is not in operation (OFF) (when a small signal is input). Therefore, when a large signal is input, the carrier amplifier 11 and the peak amplifier 21 are in operation, and a high-power signal can be output.

[0065] Next, when the carrier amplifier 11 is in operation (ON) and the peak amplifier 21 is not in operation (OFF) (when a small signal is input), the load impedance of the peak amplifier 21 becomes an open circuit state, and the load impedance of the carrier amplifier 11 becomes higher when a small signal is input than when a large signal is input. Therefore, when a small signal is input, the load impedance of the carrier amplifier 11 becomes higher, and the amplifier circuit 500 can operate with high efficiency.

[0066] However, when the carrier amplifier 11 and the peak amplifier 21 are operating (when a large signal is input), the carrier amplifier 11 has a finite impedance and does not have an ideal impedance, so a part of the output signal of the peak amplifier 21 may not be combined with the output signal of the carrier amplifier 11 but may leak to the signal output terminal 110 alone. As a result, the power efficiency of the amplifier circuit 500 may be degraded, and the linearity of the gain may be degraded, thereby causing signal distortion.

[0067] In contrast, in the amplifier circuit 10 involved in the present embodiment, a path including an auxiliary amplifier 22 and a phase shift line 42 is provided, and the signal (peak auxiliary signal) transmitted in the above path is used to offset the signal (peak signal) leaking directly from the peak amplifier 21 to the signal output terminal 110, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21.

[0068] Below, refer to Figure 1 The circuit state of the amplifier circuit 10 according to this embodiment will be described in detail.

[0069] like Figure 1As shown, first, a high-frequency main signal is input from the signal input terminal 120. It is assumed here that the phase of the high-frequency main signal is 0° at the node n1 on the path connecting the signal input terminal 120 and the distributor 50. The high-frequency main signal is power-divided by the distributor 50, so that it is output as a carrier main signal on the carrier amplifier 11 side, and is output as a peak signal and a peak auxiliary signal on the peak amplifier 21 and the auxiliary amplifier 22 side. At the node n2 on the path connecting the distributor 50 and the carrier amplifier 11, the phase of the carrier main signal does not change and is 0°. On the other hand, at the node n4 on the path connecting the phase shift line 41 to the peak amplifier 21 and the auxiliary amplifier 22, the phase of the peak signal and the peak auxiliary signal is delayed by 90° by the phase shift line 41 and becomes -90°.

[0070] Next, the phase of the carrier main signal is inverted by the carrier amplifier 11, and becomes -180° at the node n3 on the path connecting the output end of the carrier amplifier 11 and the phase shift line 43. On the other hand, the phase of the peak signal is inverted by the peak amplifier 21, and becomes -270° at the node n6 of the output end of the peak amplifier 21, and becomes -270° at the node n8 connecting the output end of the peak amplifier 21 and the phase shift line 43. In addition, the phase of the peak auxiliary signal is inverted by the auxiliary amplifier 22, and becomes -270° at the node n5 of the output end of the auxiliary amplifier 22, and is advanced by 90° to become -180° at the node n7 of the input end of the carrier amplifier 11 through the phase shift line 42. Furthermore, the phase of the peak auxiliary signal is inverted by the carrier amplifier 11, and becomes 0° at the node n3, and is delayed by 90° to become -90° at the node n8 through the phase shift line 43. Here, at the node n8 , the phase of the peak signal and the phase of the peak auxiliary signal are in anti-phase relation, so the peak signal and the peak auxiliary signal are substantially canceled out at the node n8 .

[0071] This can prevent a part of the output signal of the peak amplifier 21 from leaking to the signal output terminal 110 alone.

[0072] In addition, the gain of the auxiliary amplifier 22 is determined so that the amplitude of the peak signal and the amplitude of the peak auxiliary signal are substantially equal at the node n8. In the present embodiment, it is desirable that the gain of the auxiliary amplifier 22 is lower than the gain of the peak amplifier 21. Accordingly, the amplitude of the peak signal amplified by the peak amplifier 21 and reaching the node n8 can be made substantially equal to the amplitude of the peak auxiliary signal amplified by the auxiliary amplifier 22 and the carrier amplifier 11 and reaching the node n8.

[0073] In addition, the amplifier circuit 10 may further include an attenuator connected between the connection point between the input end of the carrier amplifier 11 and the phase shift line 42 and the output end of the auxiliary amplifier 22. In this way, the amplitude of the peak auxiliary signal can be adjusted. In addition, the attenuator may be an attenuator that can change the attenuation rate according to the power and frequency of the high-frequency signal input to the amplifier circuit 10.

[0074] Figure 3 1 is a graph schematically showing the characteristics of gain and load impedance of the amplifier circuit involved in Example 1 and the comparative example. The upper part of the figure shows the gain of the carrier amplifier 11 and the peak amplifier 21 corresponding to the output power of the amplifier circuit, and the lower part of the figure shows the load impedance at the output end of the carrier amplifier 11.

[0075] like Figure 3 As shown, in the region where the output power of the amplifier circuit is high, the peak amplifier 21 is in the ON state. At the same time, the load impedance of the carrier amplifier 11 decreases, and the carrier amplifier 11 can output a high-power signal.

[0076] In the amplifier circuit 500 according to the comparative example, the output signal of the peak amplifier 21 leaks alone to the signal output terminal 110, so the gain of the amplifier circuit 500 increases as the output power increases. Therefore, the linearity of the gain deteriorates and the signal distortion increases.

[0077] In contrast, according to the amplifier circuit 10 involved in this embodiment, it is possible to suppress the output signal of the peak amplifier 21 from leaking to the signal output terminal 110 alone, so that the gain of the amplifier circuit 10 is substantially equal to the gain of the carrier amplifier 11, and the gain can be maintained constant, thereby suppressing signal distortion. Therefore, it is possible to provide an amplifier circuit 10 in which power efficiency is improved and gain linearity is improved to suppress signal distortion.

[0078] In addition, in the amplifier circuit 10 involved in this embodiment, one end of the phase shift line 42 may be connected to the output end of the auxiliary amplifier 22, and the other end of the phase shift line 42 may be connected to the output end of the carrier amplifier 11. That is, the second phase shift circuit composed of the third phase shift circuit and the fourth phase shift circuit may be connected between the signal input terminal 120 and the output end of the carrier amplifier 11. In this case, the peak auxiliary signal does not pass through the carrier amplifier 11 but merges with the carrier main signal at the output end of the carrier amplifier 11, so it is necessary to set the phase shift line 42 as a phase shift line that lags the input signal by 90°, and set the gain of the auxiliary amplifier 22 high. According to this, the phase of the peak signal and the phase of the peak auxiliary signal can be in an anti-phase relationship at the node n8. Therefore, the peak signal and the peak auxiliary signal can be substantially offset at the node n8 to suppress the output signal of the peak amplifier 21 from leaking to the signal output terminal 110 alone, so that signal distortion can be suppressed.

[0079] In addition, in the amplifier circuit 10 involved in this embodiment, the peak amplifier 21 and the auxiliary amplifier 22 can also be composed of a peak amplifier and a power divider connected to the output end of the peak amplifier.

[0080] [2 Circuit Configurations of Amplifier Circuit 10A, High-Frequency Circuit 1A, and Communication Device 4A According to Embodiment 2]

[0081] Reference Figure 4 The circuit configurations of an amplifier circuit 10A, a high-frequency circuit 1A, and a communication device 4A according to Example 2 of the present embodiment will be described. Figure 4 It is a circuit configuration diagram of an amplifier circuit 10A, a high-frequency circuit 1A, and a communication device 4A according to the second embodiment.

[0082] [2.1 Circuit Configuration of Communication Device 4A]

[0083] like Figure 4 As shown, the communication device 4A involved in the second embodiment includes a high-frequency circuit 1A, an antenna 2, and an RFIC 3. The communication device 4A involved in this embodiment is different from the communication device 4 involved in the first embodiment only in the structure of the high-frequency circuit 1A. In addition, the high-frequency circuit 1A involved in this embodiment is different from the high-frequency circuit 1 involved in the first embodiment only in the structure of the amplifier circuit 10A. Therefore, in the following, the communication device 4A and the high-frequency circuit 1A involved in this embodiment are described mainly with the structure of the amplifier circuit 10A.

[0084] [2.2 Circuit Structure of Amplifier Circuit 10A]

[0085] like Figure 4As shown in FIG. 1 , the amplifier circuit 10A includes a signal input terminal 120, a signal output terminal 110, a carrier amplifier 11, a peak amplifier 21, an auxiliary amplifier 22, phase shift lines 41, 42, and 44, a distributor 50, and a transformer 80. The amplifier circuit 10A according to this embodiment is different from the amplifier circuit 10 according to the first embodiment in that a phase shift line 44 is provided instead of the phase shift line 43, and a transformer 80 is added. Hereinafter, the description of the amplifier circuit 10A according to this embodiment will be omitted for the same configuration as the amplifier circuit 10 according to the first embodiment, and the description will be mainly focused on the different configurations.

[0086] The input end of the carrier amplifier 11 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the signal output terminal 110 via the transformer 80 .

[0087] The input end of the peak amplifier 21 is connected to the signal input terminal 120 via the distributor 50 and the phase shift line 41 , and the output end is connected to the signal output terminal 110 via the transformer 80 and the phase shift line 44 .

[0088] The input end of the auxiliary amplifier 22 is connected to the signal input terminal 120 via the distributor 50 and the phase shift line 41 , and the output end is connected to the input end of the carrier amplifier 11 via the phase shift line 42 .

[0089] Furthermore, it is desirable that the bias voltage supplied to the auxiliary amplifier 22 is equal to the bias voltage supplied to the peak amplifier 21. Furthermore, it is desirable that the power supply voltage supplied to the auxiliary amplifier 22 is equal to the power supply voltage supplied to the peak amplifier 21, and the operating point of the auxiliary amplifier 22 is equal to the operating point of the peak amplifier 21. Accordingly, the behavior of the output signal of the auxiliary amplifier 22 can be made the same as the behavior of the output signal of the peak amplifier 21.

[0090] The phase shift line 44 is an example of a first phase shift circuit, for example, a 1 / 4 wavelength transmission line, which delays the phase of a high-frequency signal input from one end by 90° (1 / 4 wavelength) and then outputs it from the other end. In addition, the phase shift line 44 (first phase shift circuit) may not have a phase shift line, for example, it may be an inductor arranged in series in a path connecting the peak amplifier 21 and the signal output terminal 110, or a low-pass filter composed of an inductor and a capacitor. One end of the phase shift line 44 is connected to the output end of the peak amplifier 21, and the other end is connected to the other end of the input side coil 801 of the transformer 80.

[0091] The phase shift lines 41 and 42 constitute a second phase shift circuit, and are connected between the signal input terminal 120 and the input end of the carrier amplifier 11. According to the above structure, the phase shift lines 41 and 42 (second phase shift circuit) can invert the phase of the output signal of the auxiliary amplifier 22 at the signal output terminal 110 relative to the phase of the output signal of the peak amplifier 21 at the signal output terminal 110.

[0092] In addition, each of the phase shift circuits 41 and 44 is not limited to a circuit that strictly lags the phase of the input high-frequency signal of the frequency band A by 90°, and any circuit can be used as long as the phase of the input high-frequency signal of the frequency band A is delayed within the range of (90°±20°). In addition, the phase shift circuit 42 is not limited to a circuit that strictly advances the phase of the input high-frequency signal of the frequency band A by 90°, and any circuit can be used as long as the phase of the input high-frequency signal of the frequency band A is advanced within the range of (90°±20°).

[0093] The transformer 80 has an input side coil 801 and an output side coil 802 which are electromagnetically coupled to each other. One end of the input side coil 801 is connected to the output end of the carrier amplifier 11, and the other end of the input side coil 801 is connected to the other end of the phase shift line 44. One end of the output side coil 802 is connected to the signal output terminal 110, and the other end of the output side coil 802 is connected to the ground.

[0094] In the amplifier circuit 10A involved in this embodiment, a path including an auxiliary amplifier 22 and a phase shift line 42 is provided, and the signal (peak auxiliary signal) transmitted in the above path is used to offset the signal (peak signal) directly leaking from the peak amplifier 21 to the signal output terminal 110, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21.

[0095] Below, refer to Figure 4 The circuit state of the amplifier circuit 10A according to this embodiment will be described in detail.

[0096] like Figure 4 As shown, first, a high-frequency main signal is input from the signal input terminal 120. It is assumed here that the phase of the high-frequency main signal is 0° at the node n1 on the path connecting the signal input terminal 120 and the distributor 50. The high-frequency main signal is power-divided by the distributor 50, so that it is output as a carrier main signal on the carrier amplifier 11 side, and is output as a peak signal and a peak auxiliary signal on the peak amplifier 21 and the auxiliary amplifier 22 side. At the node n2 on the path connecting the distributor 50 and the carrier amplifier 11, the phase of the carrier main signal does not change and is 0°. On the other hand, at the node n4 on the path connecting the phase shift line 41 to the peak amplifier 21 and the auxiliary amplifier 22, the phase of the peak signal and the peak auxiliary signal is delayed by 90° by the phase shift line 41 and becomes -90°.

[0097] Next, the phase of the carrier main signal is inverted by the carrier amplifier 11, and becomes -180° at the node n3 at one end of the input side coil 801. On the other hand, the phase of the peak signal is inverted by the peak amplifier 21, and becomes -270° at the node n6 at the output end of the peak amplifier 21, and becomes 0° at the node n8 at the other end of the input side coil 801 after being delayed by 90° through the phase shift line 44. Furthermore, the peak signal at the node n8 is transmitted from the other end of the input side coil 801 to one end of the output side coil, and the phase of the peak signal is inverted to become -180° at the node n9 at one end of the output side coil 802. In addition, the phase of the peak auxiliary signal is inverted by the auxiliary amplifier 22, and becomes -270° at the node n5 at the output end of the auxiliary amplifier 22, and becomes -180° at the node n7 at the input end of the carrier amplifier 11 after being advanced by 90° through the phase shift line 42. Furthermore, the phase of the peak auxiliary signal is inverted by the carrier amplifier 11, and becomes 0° at the node n3. Furthermore, the peak assist signal at the node n3 is transmitted from one end of the input side coil 801 to one end of the output side coil, and the phase of the peak assist signal is not inverted but is 0° at the node n9.

[0098] Here, at the node n9, the phase of the peak signal and the phase of the peak auxiliary signal are in anti-phase relation, so the peak signal and the peak auxiliary signal are substantially canceled out at the node n9. Accordingly, it is possible to suppress a part of the output signal of the peak amplifier 21 from leaking to the signal output terminal 110 alone. Therefore, it is possible to provide an amplifier circuit 10A in which power efficiency is improved, gain linearity is improved, and signal distortion is suppressed.

[0099] In addition, the gain of the auxiliary amplifier 22 is determined so that the amplitude of the peak signal and the amplitude of the peak auxiliary signal are substantially equal at the node n9. In the present embodiment, it is desirable that the gain of the auxiliary amplifier 22 is lower than the gain of the peak amplifier 21. Accordingly, the amplitude of the peak signal amplified by the peak amplifier 21 and reaching the node n9 can be made substantially equal to the amplitude of the peak auxiliary signal amplified by the auxiliary amplifier 22 and the carrier amplifier 11 and reaching the node n9.

[0100] In addition, the amplifier circuit 10A may further include an attenuator connected between the connection point between the input end of the carrier amplifier 11 and the phase shift line 42 and the output end of the auxiliary amplifier 22. In this way, the amplitude of the peak auxiliary signal can be adjusted. In addition, the attenuator may be an attenuator that can change the attenuation rate according to the power and frequency of the high-frequency signal input to the amplifier circuit 10A.

[0101] In addition, in the amplifier circuit 10A involved in this embodiment, one end of the phase shift line 42 may be connected to the output end of the auxiliary amplifier 22, and the other end of the phase shift line 42 may be connected to the output end of the carrier amplifier 11. That is, the second phase shift circuit composed of the third phase shift circuit and the fourth phase shift circuit may be connected between the signal input terminal 120 and the output end of the carrier amplifier 11. In this case, the peak auxiliary signal does not pass through the carrier amplifier 11 but merges with the carrier main signal at the output end of the carrier amplifier 11, so it is necessary to set the phase shift line 42 as a phase shift line that lags the input signal by 90°, and set the gain of the auxiliary amplifier 22 high. According to this, the phase of the peak signal and the phase of the peak auxiliary signal can be in an anti-phase relationship at the node n9. Therefore, the peak signal and the peak auxiliary signal can be substantially offset at the node n9 to suppress the output signal of the peak amplifier 21 from leaking to the signal output terminal 110 alone, so that signal distortion can be suppressed.

[0102] In the amplifier circuit 10A according to the present embodiment, the peak amplifier 21 and the auxiliary amplifier 22 may be composed of one peak amplifier and a power divider connected to the output terminal of the peak amplifier.

[0103] [3 Circuit Configuration of Amplifier Circuit 10B According to Embodiment 3]

[0104] Reference Figure 5 A circuit configuration of an amplifier circuit 10B according to Example 3 of the present embodiment will be described. Figure 5 1 is a circuit diagram of an amplifier circuit 10B according to the third embodiment. As shown in the figure, the amplifier circuit 10B includes a signal input terminal 120 and a signal output terminal 110, a carrier amplifier 11, a peak amplifier 21, an auxiliary amplifier 22, phase shift lines 43 and 45, and a distributor 50. The amplifier circuit 10B according to the present embodiment is different from the amplifier circuit 10 according to the first embodiment in that a phase shift line 45 is provided instead of the phase shift lines 41 and 42. In the following, the description of the amplifier circuit 10B according to the present embodiment will be omitted for the same configuration as the amplifier circuit 10 according to the first embodiment, and the description will be centered on the different configuration.

[0105] The input end of the carrier amplifier 11 is connected to the signal input terminal 120 via the distributor 50 and the phase shift line 45 , and the output end is connected to the signal output terminal 110 via the phase shift line 43 .

[0106] The input end of the peak amplifier 21 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the signal output terminal 110 .

[0107] The input end of the auxiliary amplifier 22 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the input end of the carrier amplifier 11 via the phase shift line 45 .

[0108] Furthermore, it is desirable that the bias voltage supplied to the auxiliary amplifier 22 is equal to the bias voltage supplied to the peak amplifier 21. Furthermore, it is desirable that the power supply voltage supplied to the auxiliary amplifier 22 is equal to the power supply voltage supplied to the peak amplifier 21, and the operating point of the auxiliary amplifier 22 is equal to the operating point of the peak amplifier 21. Accordingly, the behavior of the output signal of the auxiliary amplifier 22 can be made the same as the behavior of the output signal of the peak amplifier 21.

[0109] The phase shift circuit 45 is an example of a second phase shift circuit, which makes the phase of the high-frequency signal input from one end thereof advance by 90° (1 / 4 wavelength) (or lag by 270°) and then output from the other end. In addition, the phase shift circuit 45 (second phase shift circuit) may not have such a phase shift circuit, for example, it may be a capacitor arranged in series in the path connecting the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11, or a high-pass filter composed of a capacitor and an inductor. One end of the phase shift circuit 45 is connected to the connection point between the signal input terminal 120 (distributor 50) and the output end of the auxiliary amplifier 22, and the other end is connected to the input end of the carrier amplifier 11.

[0110] The phase shift circuit 45 is connected between the signal input terminal 120 and the input end of the carrier amplifier 11 , and is configured to invert the phase of the output signal of the auxiliary amplifier 22 at the signal output terminal 110 relative to the phase of the output signal of the peak amplifier 21 at the signal output terminal 110 .

[0111] The phase shift circuit 45 is not limited to a circuit that advances the phase of the input high frequency signal of the frequency band A strictly by 90°, and any circuit may be used as long as it advances the phase of the input high frequency signal of the frequency band A within a range of (90°±20°).

[0112] The distributor 50 is an example of a power distributor, and is connected between the signal input terminal 120 and the input end of the carrier amplifier 11, the input end of the peak amplifier 21, and the input end of the auxiliary amplifier 22. The distributor 50 has a first terminal, a second terminal, and a third terminal, the first terminal is connected to the signal input terminal 120, the second terminal is connected to the input end of the carrier amplifier 11, and the third terminal is connected to the input end of the peak amplifier 21 and the input end of the auxiliary amplifier 22.

[0113] In the amplifier circuit 10B involved in this embodiment, a path including an auxiliary amplifier 22 and a phase shift line 45 is provided, and the signal (peak auxiliary signal) transmitted in the above path is used to offset the signal (peak signal) directly leaking from the peak amplifier 21 to the signal output terminal 110, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21.

[0114] Below, refer to Figure 5 The circuit state of the amplifier circuit 10B according to this embodiment will be described in detail.

[0115] like Figure 5 As shown, first, a high-frequency main signal is input from the signal input terminal 120. It is assumed here that the phase of the high-frequency main signal is 0° at the node n1 on the path connecting the signal input terminal 120 and the distributor 50. The high-frequency main signal is power-divided by the distributor 50, so that it is output as a carrier main signal on the carrier amplifier 11 side, and is output as a peak signal and a peak auxiliary signal on the peak amplifier 21 and the auxiliary amplifier 22 side. At the node n2 on the path connecting the distributor 50 and the phase shift line 45, the phase of the carrier main signal does not change and is 0°, and at the node n7 at the input end of the carrier amplifier 11, it is advanced by 90° through the phase shift line 45 to become +90°.

[0116] On the other hand, at the node n6 at the output end of the peak amplifier 21, the phase of the peak signal is inverted by the peak amplifier 21 to -180°, and at the node n8 connecting the output end of the peak amplifier 21 to the phase shift line 43, it becomes -180°. In addition, the phase of the peak auxiliary signal is inverted by the auxiliary amplifier 22 to -180° at the node n5 at the output end of the auxiliary amplifier 22, and is advanced by 90° to -90° at the node n7 by the phase shift line 45. Furthermore, the phase of the peak auxiliary signal is inverted by the carrier amplifier 11 to +90° at the node n3 at the output end of the carrier amplifier 11, and is delayed by 90° to 0° at the node n8 by the phase shift line 43. Here, at the node n8, the phase of the peak signal and the phase of the peak auxiliary signal are in anti-phase relationship, so the peak signal and the peak auxiliary signal are substantially offset at the node n8.

[0117] This can suppress a part of the output signal of the peak amplifier 21 from leaking to the signal output terminal 110. Therefore, it is possible to provide an amplifier circuit 10B in which power efficiency is improved and gain linearity is enhanced to suppress signal distortion.

[0118] In addition, the gain of the auxiliary amplifier 22 is determined so that the amplitude of the peak signal and the amplitude of the peak auxiliary signal are substantially equal at the node n8. In the present embodiment, it is desirable that the gain of the auxiliary amplifier 22 is lower than the gain of the peak amplifier 21. Accordingly, the amplitude of the peak signal amplified by the peak amplifier 21 and reaching the node n8 can be made substantially equal to the amplitude of the peak auxiliary signal amplified by the auxiliary amplifier 22 and the carrier amplifier 11 and reaching the node n8.

[0119] In the amplifier circuit 10B according to the present embodiment, the peak amplifier 21 and the auxiliary amplifier 22 may be composed of one peak amplifier and a power divider connected to the output terminal of the peak amplifier.

[0120] [4 Circuit Configuration of Amplifier Circuit 10C According to Embodiment 4]

[0121] Reference Figure 6 A circuit configuration of an amplifier circuit 10C according to Example 4 of the present embodiment will be described. Figure 6 1 is a circuit diagram of an amplifier circuit 10C according to the fourth embodiment. As shown in the figure, the amplifier circuit 10C includes a signal input terminal 120 and a signal output terminal 110, a carrier amplifier 11, a peak amplifier 21, an auxiliary amplifier 22, phase shift lines 45 and 46, a distributor 50, and a transformer 80. The amplifier circuit 10C according to the present embodiment is different from the amplifier circuit 10B according to the third embodiment in that a phase shift line 46 is provided instead of the phase shift line 43, and a transformer 80 is added. In the following, the description of the amplifier circuit 10C according to the present embodiment will be omitted for the same configuration as the amplifier circuit 10B according to the third embodiment, and the description will be centered on the different configurations.

[0122] The input end of the carrier amplifier 11 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the signal output terminal 110 via the transformer 80 .

[0123] The input end of the peak amplifier 21 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the signal output terminal 110 via the transformer 80 and the phase shift line 46 .

[0124] The input end of the auxiliary amplifier 22 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the input end of the carrier amplifier 11 via the phase shift line 45 .

[0125] Furthermore, it is desirable that the bias voltage supplied to the auxiliary amplifier 22 is equal to the bias voltage supplied to the peak amplifier 21. Furthermore, it is desirable that the power supply voltage supplied to the auxiliary amplifier 22 is equal to the power supply voltage supplied to the peak amplifier 21, and the operating point of the auxiliary amplifier 22 is equal to the operating point of the peak amplifier 21. Accordingly, the behavior of the output signal of the auxiliary amplifier 22 can be made the same as the behavior of the output signal of the peak amplifier 21.

[0126] The phase shift line 46 is an example of a first phase shift circuit, for example, a 1 / 4 wavelength transmission line, which delays the phase of a high-frequency signal input from one end by 90° (1 / 4 wavelength) and then outputs it from the other end. In addition, the phase shift line 46 (first phase shift circuit) may not have a phase shift line, for example, it may be an inductor arranged in series in a path connecting the peak amplifier 21 and the signal output terminal 110, or a low-pass filter composed of an inductor and a capacitor. One end of the phase shift line 46 is connected to the output end of the peak amplifier 21, and the other end is connected to the other end of the input side coil 801 of the transformer 80.

[0127] The phase shift circuit 45 is connected between the signal input terminal 120 and the input end of the carrier amplifier 11 , and is configured to invert the phase of the output signal of the auxiliary amplifier 22 at the signal output terminal 110 relative to the phase of the output signal of the peak amplifier 21 at the signal output terminal 110 .

[0128] The transformer 80 has an input side coil 801 and an output side coil 802 which are electromagnetically coupled to each other. One end of the input side coil 801 is connected to the output end of the carrier amplifier 11, and the other end of the input side coil 801 is connected to the other end of the phase shift line 46. One end of the output side coil 802 is connected to the signal output terminal 110, and the other end of the output side coil 802 is connected to the ground.

[0129] In the amplifier circuit 10C involved in this embodiment, a path including an auxiliary amplifier 22 and a phase shift line 45 is provided, and the signal (peak auxiliary signal) transmitted in the above path is used to offset the signal (peak signal) directly leaking from the peak amplifier 21 to the signal output terminal 110, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21.

[0130] Below, refer to Figure 6 The circuit state of the amplifier circuit 10C according to this embodiment will be described in detail.

[0131] like Figure 6As shown, first, a high-frequency main signal is input from the signal input terminal 120. It is assumed here that the phase of the high-frequency main signal is 0° at the node n1 on the path connecting the signal input terminal 120 and the distributor 50. The high-frequency main signal is power-divided by the distributor 50, so that it is output as a carrier main signal on the carrier amplifier 11 side, and is output as a peak signal and a peak auxiliary signal on the peak amplifier 21 and the auxiliary amplifier 22 side. At the node n2 on the path connecting the distributor 50 and the phase shift line 45, the phase of the carrier main signal does not change and is 0°, and at the node n7 at the input end of the carrier amplifier 11, it is advanced by 90° through the phase shift line 45 to become +90°.

[0132] On the other hand, at the node n6 at the output end of the peak amplifier 21, the phase of the peak signal is inverted by the peak amplifier 21 to -180°, and at the node n8 at the other end of the input side coil 801, it is -270° through the phase shift line 46. In addition, the phase of the peak auxiliary signal is inverted by the auxiliary amplifier 22 to -180° at the node n5 at the output end of the auxiliary amplifier 22, and is advanced by 90° to -90° at the node n7 through the phase shift line 45. Furthermore, the phase of the peak auxiliary signal is inverted by the carrier amplifier 11 to +90° at the node n3 at the output end of the carrier amplifier 11.

[0133] Next, the peak signal at the node n8 is transmitted from the other end of the input side coil 801 to one end of the output side coil, and the phase of the peak signal is inverted to -90° at the node n9 at one end of the output side coil 802. In addition, the peak auxiliary signal is transmitted from one end of the input side coil 801 to one end of the output side coil, and the phase of the peak auxiliary signal is not inverted to +90° at the node n9. Here, at the node n9, the phase of the peak signal and the phase of the peak auxiliary signal are in an anti-phase relationship, so the peak signal and the peak auxiliary signal are substantially offset at the node n9.

[0134] This can suppress a part of the output signal of the peak amplifier 21 from leaking to the signal output terminal 110. Therefore, it is possible to provide an amplifier circuit 10C in which power efficiency is improved and gain linearity is enhanced to suppress signal distortion.

[0135] In addition, the gain of the auxiliary amplifier 22 is determined so that the amplitude of the peak signal and the amplitude of the peak auxiliary signal are substantially equal at the node n9. In the present embodiment, it is desirable that the gain of the auxiliary amplifier 22 is lower than the gain of the peak amplifier 21. Accordingly, the amplitude of the peak signal amplified by the peak amplifier 21 and reaching the node n9 can be made substantially equal to the amplitude of the peak auxiliary signal amplified by the auxiliary amplifier 22 and the carrier amplifier 11 and reaching the node n9.

[0136] In addition, the amplifier circuit 10C may further include an attenuator connected between the connection point between the signal input terminal 120 (distributor 50) and the output end of the auxiliary amplifier 22 and the output end of the auxiliary amplifier 22. In this way, the amplitude of the peak auxiliary signal can be adjusted. In addition, the attenuator may be an attenuator that can change the attenuation rate according to the power and frequency of the high-frequency signal input to the amplifier circuit 10C.

[0137] In the amplifier circuit 10C according to the present embodiment, the peak amplifier 21 and the auxiliary amplifier 22 may be composed of one peak amplifier and a power divider connected to the output terminal of the peak amplifier.

[0138] [5 Circuit Configuration of Amplifier Circuit 10D According to Embodiment 5]

[0139] Reference Figure 7 A circuit configuration of an amplifier circuit 10D according to Example 5 of the present embodiment will be described. Figure 7 1 is a circuit diagram of an amplifier circuit 10D according to the fifth embodiment. As shown in the figure, the amplifier circuit 10D includes a signal input terminal 120 and a signal output terminal 110, a carrier amplifier 11, a peak amplifier 21, an auxiliary amplifier 22, phase shift lines 43 and 45, a distributor 50, and an attenuator 73. The amplifier circuit 10D according to the present embodiment is different from the amplifier circuit 10B according to the third embodiment in that an attenuator 73 is added. Hereinafter, the description of the amplifier circuit 10D according to the present embodiment will be omitted for the same configuration as the amplifier circuit 10B according to the third embodiment, and the description will be centered on the different configurations.

[0140] The attenuator 73 is connected between a connection point between the signal input terminal 120 (distributor 50 ) and the output end of the auxiliary amplifier 22 and the output end of the auxiliary amplifier 22 .

[0141] The input end of the carrier amplifier 11 is connected to the signal input terminal 120 via the distributor 50 and the phase shift line 45 , and the output end is connected to the signal output terminal 110 via the phase shift line 43 .

[0142] The input end of the peak amplifier 21 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the signal output terminal 110 .

[0143] The input end of the auxiliary amplifier 22 is connected to the signal input terminal 120 via the distributor 50 , and the output end is connected to the input end of the carrier amplifier 11 via the phase shift line 45 and the attenuator 73 .

[0144] One end of the phase shift line 45 is connected to the connection point between the signal input terminal 120 (distributor 50 ) and the attenuator, and the other end is connected to the input end of the carrier amplifier 11 .

[0145] According to the above configuration, the amplifier circuit 10D utilizes a path provided with the auxiliary amplifier 22, the attenuator 73, and the phase shift line 45, and utilizes the signal (peak auxiliary signal) transmitted in the above path to cancel the signal (peak signal) leaking directly from the peak amplifier 21 to the signal output terminal 110, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. In addition, by configuring the attenuator 73, the amplitude of the peak auxiliary signal can be adjusted, so the peak signal can be canceled with high accuracy using the peak auxiliary signal. In addition, the attenuator 73 can also be an attenuator that can change the attenuation rate according to the power and frequency of the high-frequency signal input to the amplifier circuit 10D.

[0146] [6 Effects, etc.]

[0147] As described above, the amplifier circuit 10 according to the first embodiment, the amplifier circuit 10A according to the second embodiment, the amplifier circuit 10B according to the third embodiment, the amplifier circuit 10C according to the fourth embodiment, and the amplifier circuit 10D according to the fifth embodiment include: a signal input terminal 120 and a signal output terminal 110; a carrier amplifier 11 connected between the signal input terminal 120 and the signal output terminal 110; a peak amplifier 21 connected between the signal input terminal 120 and the signal output terminal 110; a first phase shift circuit connected between the first and second phases; between the carrier amplifier 11 and the signal output terminal 110, or between the peak amplifier 21 and the signal output terminal 110; an auxiliary amplifier 22, which is connected between the signal input terminal 120 and the input end or the output end of the carrier amplifier 11; and a second phase shift circuit, which is connected between the signal input terminal 120 and the input end or the output end of the carrier amplifier 11, and is configured to invert the phase of the output signal of the auxiliary amplifier 22 at the signal output terminal 110 relative to the phase of the output signal of the peak amplifier 21 at the signal output terminal 110.

[0148] According to this, by using the signal transmitted in the path connecting the auxiliary amplifier 22 and the signal output terminal 110 to cancel the signal leaking from the peak amplifier 21 to the signal output terminal 110, it is possible to suppress the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide the amplifier circuits 10, 10A, 10B, 10C, and 10D in which the power efficiency is improved and the linearity of the gain is improved to suppress the signal distortion.

[0149] In addition, for example, in the amplifier circuit 10, the second phase shift circuit includes: a phase shift circuit 41 (third phase shift circuit), which is connected between the connection point between the input end of the peak amplifier 21 and the input end of the auxiliary amplifier 22 and the signal input terminal 120; and a phase shift circuit 42 (fourth phase shift circuit), which is connected between the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11, one end of the phase shift circuit 43 (first phase shift circuit) is connected to the output end of the carrier amplifier 11, and the other end of the phase shift circuit 43 (first phase shift circuit) is connected to the connection point between the output end of the peak amplifier 21 and the signal output terminal 110.

[0150] According to this, by providing the path including the auxiliary amplifier 22 and the phase shift line 42, the signal leaking from the peak amplifier 21 to the signal output terminal 110 is offset by the signal transmitted in the above path, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide the amplifier circuit 10 in which the power efficiency is improved and the linearity of the gain is improved to suppress the signal distortion.

[0151] In addition, for example, the amplifier circuit 10A has a transformer 80, which has an input side coil 801 and an output side coil 802, one end of the phase shift line 44 (first phase shift circuit) is connected to the output end of the peak amplifier 21, one end of the input side coil 801 is connected to the output end of the carrier amplifier, the other end of the input side coil 801 is connected to the other end of the phase shift line 44 (first phase shift circuit), one end of the output side coil 802 is connected to the signal output terminal 110, and the other end of the output side coil 802 is connected to the ground, and the second phase shift circuit includes: the phase shift line 41 (third phase shift circuit), which is connected between the connection point between the input end of the peak amplifier 21 and the input end of the auxiliary amplifier 22 and the signal input terminal 120; and the phase shift line 42 (fourth phase shift circuit), which is connected between the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11.

[0152] According to this, by providing the path including the auxiliary amplifier 22 and the phase shift line 42, the signal leaking from the peak amplifier 21 to the signal output terminal 110 is offset by the signal transmitted in the above path, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide an amplifier circuit 10A in which the power efficiency is improved and the linearity of the gain is improved to suppress the signal distortion.

[0153] In addition, for example, in the amplifier circuits 10 and 10A, the carrier amplifier 11, the peak amplifier 21 and the auxiliary amplifier 22 are each an inverting amplifier, the first phase shift circuit is a phase shift circuit that lags the input signal by 90°, the third phase shift circuit is a phase shift circuit that lags the input signal by 90°, and the fourth phase shift circuit is a phase shift circuit that advances the input signal by 90°.

[0154] Accordingly, the amplifier circuit 10 can be made into a current synthesis type Doherty amplifier circuit through the first phase shift circuit. In addition, the amplifier circuit 10A can be made into a voltage synthesis type Doherty amplifier circuit through the first phase shift circuit, and the peak signal leaking to the signal output terminal 110 can be offset with high precision using the peak auxiliary signal through the second phase shift circuit.

[0155] In addition, for example, the amplifier circuits 10 and 10A further include an attenuator connected between a connection point between the input terminal of the carrier amplifier 11 and the fourth phase shift circuit and an output terminal of the auxiliary amplifier 22 .

[0156] According to this, by arranging the attenuator on the path where the auxiliary amplifier 22 and the fourth phase shift circuit are provided, the amplitude of the peak assist signal can be adjusted, so that the peak signal can be canceled with high accuracy using the peak assist signal.

[0157] In addition, for example, in the amplifier circuits 10 and 10A, the gain of the auxiliary amplifier 22 is lower than the gain of the peak amplifier 21 .

[0158] Thus, the amplitude of the peak signal amplified by the peak amplifier 21 and reaching the signal output terminal 110 can be made substantially equal to the amplitude of the peak auxiliary signal amplified by the auxiliary amplifier 22 and the carrier amplifier 11 and reaching the signal output terminal 110 .

[0159] In addition, for example, in the amplifier circuit 10B, the phase shift circuit 45 (second phase shift circuit) is connected between the connection point between the signal input terminal 120 and the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11, one end of the phase shift circuit 43 (first phase shift circuit) is connected to the output end of the carrier amplifier 11, and the other end of the phase shift circuit 43 (first phase shift circuit) is connected to the connection point between the output end of the peak amplifier 21 and the signal output terminal 110.

[0160] According to this, by providing the path including the auxiliary amplifier 22 and the phase shift line 45, the signal leaking from the peak amplifier 21 to the signal output terminal 110 is offset by the signal transmitted in the above path, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide an amplifier circuit 10B in which the power efficiency is improved and the linearity of the gain is improved to suppress the signal distortion.

[0161] In addition, for example, the amplifier circuit 10C further includes a transformer 80, which has an input side coil 801 and an output side coil 802, one end of the phase shift circuit 46 (first phase shift circuit) is connected to the output end of the peak amplifier 21, one end of the input side coil 801 is connected to the output end of the carrier amplifier 11, the other end of the input side coil 801 is connected to the other end of the phase shift circuit 46 (first phase shift circuit), one end of the output side coil 802 is connected to the signal output terminal 110, the other end of the output side coil 802 is connected to the ground, and the phase shift circuit 45 (second phase shift circuit) is connected between the connection point between the signal input terminal 120 and the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11.

[0162] According to this, by providing the path including the auxiliary amplifier 22 and the phase shift line 45, the signal leaking from the peak amplifier 21 to the signal output terminal 110 is offset by the signal transmitted in the above path, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide an amplifier circuit 10C in which the power efficiency is improved and the linearity of the gain is improved to suppress the signal distortion.

[0163] In addition, for example, in amplifier circuits 10B and 10C, the carrier amplifier 11, the peak amplifier 21, and the auxiliary amplifier 22 are each an inverting amplifier, the first phase shift circuit is a phase shift circuit that lags the input signal by 90°, and the second phase shift circuit is a phase shift circuit that advances the input signal by 90°.

[0164] Accordingly, the amplifier circuit 10B can be made into a current synthesis type Doherty amplifier circuit through the first phase shift circuit, and the amplifier circuit 10C can be made into a voltage synthesis type Doherty amplifier circuit through the first phase shift circuit, and the peak signal leaking to the signal output terminal 110 can be offset with high precision using the peak auxiliary signal through the second phase shift circuit.

[0165] In addition, for example, the amplifier circuits 10B and 10C further include an attenuator connected between a connection point between the signal input terminal 120 and the output end of the auxiliary amplifier 22 and the output end of the auxiliary amplifier 22 .

[0166] According to this, by arranging the attenuator on the path where the auxiliary amplifier 22 and the second phase shift circuit are provided, the amplitude of the peak assist signal can be adjusted, so that the peak signal can be canceled with high accuracy using the peak assist signal.

[0167] In addition, for example, in the amplifier circuits 10B and 10C, the gain of the auxiliary amplifier 22 is lower than the gain of the peak amplifier 21 .

[0168] Thus, the amplitude of the peak signal amplified by the peak amplifier 21 and reaching the signal output terminal 110 can be made substantially equal to the amplitude of the peak auxiliary signal amplified by the auxiliary amplifier 22 and the carrier amplifier 11 and reaching the signal output terminal 110 .

[0169] In addition, for example, the amplifier circuits 10 , 10A, 10B, 10C, and 10D further include a distributor 50 connected between the signal input terminal 120 and the input end of the carrier amplifier 11 , the input end of the peak amplifier 21 , and the input end of the auxiliary amplifier 22 .

[0170] Accordingly, the high-frequency signal input to the signal input terminal 120 can be power-divided at a prescribed distribution ratio, and one side of the high-frequency signal obtained by the power distribution can be output to the carrier amplifier 11, and the other side of the high-frequency signal obtained by the power distribution can be output to the peak amplifier 21 and the auxiliary amplifier 22.

[0171] In addition, for example, in the amplifier circuits 10 , 10A, 10B, 10C, and 10D, the bias voltage supplied to the auxiliary amplifier 22 is equal to the bias voltage supplied to the peak amplifier 21 .

[0172] As a result, the behavior of the output signal of the auxiliary amplifier 22 can be made the same as the behavior of the output signal of the peak amplifier 21 , and thus the peak signal leaking to the signal output terminal 110 can be accurately canceled by the peak auxiliary signal.

[0173] In addition, the amplifier circuit 10B involved in Example 3 includes: a signal input terminal 120 and a signal output terminal 110; a carrier amplifier 11, which is connected between the signal input terminal 120 and the signal output terminal 110; a peak amplifier 21, which is connected between the signal input terminal 120 and the signal output terminal 110; a first phase shift circuit, which is connected between the output end of the carrier amplifier 11 and the signal output terminal 110; an auxiliary amplifier 22, which is connected between the signal input terminal 120 and the input end of the carrier amplifier 11; and a second phase shift circuit, which is connected between the connection point of the signal input terminal 120 and the output end of the auxiliary amplifier 22 and the input end of the carrier amplifier 11.

[0174] According to this, by providing the path including the auxiliary amplifier 22 and the second phase shift circuit, the signal leaking from the peak amplifier 21 to the signal output terminal 110 is offset by the signal transmitted in the above path, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide an amplifier circuit 10B in which power efficiency is improved and gain linearity is improved to suppress signal distortion.

[0175] In addition, the amplifier circuit 10C involved in the fourth embodiment includes: a signal input terminal 120 and a signal output terminal 110; a carrier amplifier 11 connected between the signal input terminal 120 and the signal output terminal 110; a peak amplifier 21 connected between the signal input terminal 120 and the signal output terminal 110; a first phase shift circuit and a second phase shift circuit; an auxiliary amplifier 22 connected between the signal input terminal 120 and the input end of the carrier amplifier 11; and a transformer 80 having an input side coil 801 and an output side coil 802. 02, wherein one end of the first phase shift circuit is connected to the output end of the peak amplifier 21, one end of the input side coil 801 is connected to the output end of the carrier amplifier 11, the other end of the input side coil 801 is connected to the other end of the first phase shift circuit, one end of the output side coil 802 is connected to the signal output terminal 110, the other end of the output side coil 802 is connected to the ground, one end of the second phase shift circuit is connected to the connection point of the signal input terminal 120 and the output end of the auxiliary amplifier 22, and the other end of the second phase shift circuit is connected to the input end of the carrier amplifier 11.

[0176] According to this, by providing the path including the auxiliary amplifier 22 and the second phase shift circuit, the signal leaking from the peak amplifier 21 to the signal output terminal 110 is offset by the signal transmitted in the above path, thereby suppressing the distortion of the output signal caused by the operation of the peak amplifier 21. Therefore, it is possible to provide an amplifier circuit 10C in which power efficiency is improved and gain linearity is improved to suppress signal distortion.

[0177] (Other Implementations, etc.)

[0178] In the above, the amplifier circuit involved in the implementation mode of the present invention is described by listing the embodiments, but the amplifier circuit involved in the present invention is not limited to the above embodiments. Other embodiments implemented by combining any structural elements in the above embodiments, modified examples obtained by implementing various modifications that can be thought of by those skilled in the art without departing from the scope of the present invention to the above embodiments, and various devices in which the above amplifier circuit is built-in are also included in the present invention.

[0179] Furthermore, for example, in the amplifier circuit, high-frequency circuit, and communication device according to the above-described embodiments, other circuit elements and wirings may be inserted between paths connecting the circuit elements and signal paths disclosed in the drawings.

[0180] The features of the amplifier circuit described based on the above-mentioned embodiments are shown below.

[0181] <1>

[0182] An amplifier circuit comprising:

[0183] Input terminals and output terminals;

[0184] a carrier amplifier connected between the input terminal and the output terminal;

[0185] a peak amplifier connected between the input terminal and the output terminal;

[0186] a first phase shift circuit connected between the carrier amplifier and the output terminal, or connected between the peak amplifier and the output terminal;

[0187] an auxiliary amplifier connected between the input terminal and an input end or an output end of the carrier amplifier; and

[0188] The second phase shift circuit is connected between the input terminal and the input end or the output end of the carrier amplifier and is configured to invert the phase of the output signal of the auxiliary amplifier at the output terminal relative to the phase of the output signal of the peak amplifier at the output terminal.

[0189] <2>

[0190] according to <1> The amplifier circuit described herein, wherein

[0191] The second phase shift circuit comprises:

[0192] a third phase shift circuit connected between a connection point between the input end of the peak amplifier and the input end of the auxiliary amplifier and the input terminal; and

[0193] a fourth phase shift circuit connected between the output terminal of the auxiliary amplifier and the input terminal of the carrier amplifier,

[0194] One end of the first phase shift circuit is connected to the output end of the carrier amplifier, and the other end of the first phase shift circuit is connected to a connection point between the output end of the peak amplifier and the output terminal.

[0195] <3>

[0196] according to <1> The amplifier circuit described herein, wherein

[0197] A transformer is also provided, the transformer having an input-side coil and an output-side coil,

[0198] One end of the first phase shift circuit is connected to the output end of the peak amplifier,

[0199] One end of the input side coil is connected to the output end of the carrier amplifier,

[0200] The other end of the input side coil is connected to the other end of the first phase shift circuit.

[0201] One end of the output side coil is connected to the output terminal,

[0202] The other end of the output side coil is connected to the ground.

[0203] The second phase shift circuit comprises:

[0204] a third phase shift circuit connected between a connection point between the input end of the peak amplifier and the input end of the auxiliary amplifier and the input terminal; and

[0205] A fourth phase shift circuit is connected between the output end of the auxiliary amplifier and the input end of the carrier amplifier.

[0206] <4>

[0207] according to <2> or <3> The amplifier circuit described herein, wherein

[0208] The carrier amplifier, the peak amplifier and the auxiliary amplifier are each an inverting amplifier,

[0209] The first phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°.

[0210] The third phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°.

[0211] The fourth phase shift circuit is a phase shift circuit that advances the input signal by 90°.

[0212] <5>

[0213] according to <2> to <4> An amplifier circuit as described in any one of the above, wherein:

[0214] An attenuator is also provided, and the attenuator is connected between a connection point between an input end of the carrier amplifier and the fourth phase shift circuit and an output end of the auxiliary amplifier.

[0215] <6>

[0216] according to <2> to <4> An amplifier circuit as described in any one of the above, wherein:

[0217] The gain of the auxiliary amplifier is lower than the gain of the peak amplifier.

[0218] <7>

[0219] according to <1> The amplifier circuit described herein, wherein

[0220] The second phase shift circuit is connected between the connection point between the input terminal and the output end of the auxiliary amplifier and the input end of the carrier amplifier.

[0221] One end of the first phase shift circuit is connected to the output end of the carrier amplifier, and the other end of the first phase shift circuit is connected to a connection point between the output end of the peak amplifier and the output terminal.

[0222] <8>

[0223] according to <1> The amplifier circuit described herein, wherein

[0224] A transformer is also provided, the transformer having an input-side coil and an output-side coil,

[0225] One end of the first phase shift circuit is connected to the output end of the peak amplifier,

[0226] One end of the input side coil is connected to the output end of the carrier amplifier,

[0227] The other end of the input side coil is connected to the other end of the first phase shift circuit.

[0228] One end of the output side coil is connected to the output terminal,

[0229] The other end of the output side coil is connected to the ground.

[0230] The second phase shift circuit is connected between a connection point between the input terminal and the output end of the auxiliary amplifier and an input end of the carrier amplifier.

[0231] <9>

[0232] according to <7> or <8> The amplifier circuit described herein, wherein

[0233] The carrier amplifier, the peak amplifier and the auxiliary amplifier are each an inverting amplifier,

[0234] The first phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°.

[0235] The second phase shift circuit is a phase shift circuit that advances the input signal by 90°.

[0236] <10>

[0237] according to <7> to <9> An amplifier circuit as described in any one of the above, wherein:

[0238] An attenuator is further provided, and the attenuator is connected between a connection point between the input terminal and the output end of the auxiliary amplifier and the output end of the auxiliary amplifier.

[0239] <11>

[0240] according to <7> to <9> An amplifier circuit as described in any one of the above, wherein:

[0241] The gain of the auxiliary amplifier is lower than the gain of the peak amplifier.

[0242] <12>

[0243] according to <1> to <11> An amplifier circuit as described in any one of the above, wherein:

[0244] A power divider is further provided, and the power divider is connected between the input terminal and the input end of the carrier amplifier, the input end of the peak amplifier, and the input end of the auxiliary amplifier.

[0245] <13>

[0246] according to <1> to <12> An amplifier circuit as described in any one of the above, wherein:

[0247] The bias voltage provided to the auxiliary amplifier is equal to the bias voltage provided to the peak amplifier.

[0248] <14>

[0249] An amplifier circuit comprising:

[0250] Input terminals and output terminals;

[0251] a carrier amplifier connected between the input terminal and the output terminal;

[0252] a peak amplifier connected between the input terminal and the output terminal;

[0253] A first phase shift circuit connected between the output end of the carrier amplifier and the output terminal;

[0254] an auxiliary amplifier connected between the input terminal and an input end of the carrier amplifier; and

[0255] The second phase shift circuit is connected between a connection point between the input terminal and the output end of the auxiliary amplifier and the input end of the carrier amplifier.

[0256] <15>

[0257] An amplifier circuit comprising:

[0258] Input terminals and output terminals;

[0259] a carrier amplifier connected between the input terminal and the output terminal;

[0260] a peak amplifier connected between the input terminal and the output terminal;

[0261] a first phase shifting circuit and a second phase shifting circuit;

[0262] an auxiliary amplifier connected between the input terminal and an input end of the carrier amplifier; and

[0263] A transformer having an input side coil and an output side coil,

[0264] Wherein, one end of the first phase shift circuit is connected to the output end of the peak amplifier,

[0265] One end of the input side coil is connected to the output end of the carrier amplifier,

[0266] The other end of the input side coil is connected to the other end of the first phase shift circuit.

[0267] One end of the output side coil is connected to the output terminal,

[0268] The other end of the output side coil is connected to the ground.

[0269] One end of the second phase shift circuit is connected to a connection point between the input terminal and the output end of the auxiliary amplifier.

[0270] The other end of the second phase shift circuit is connected to the input end of the carrier amplifier.

[0271] <16>

[0272] according to <14> or <15> The amplifier circuit described herein, wherein

[0273] The carrier amplifier, the peak amplifier and the auxiliary amplifier are each an inverting amplifier,

[0274] The first phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°.

[0275] The second phase shift circuit is a phase shift circuit that advances the input signal by 90°.

[0276] <17>

[0277] according to <14> to <16> An amplifier circuit as described in any one of the above, wherein:

[0278] A power divider is further provided, and the power divider is connected between the input terminal and the input end of the carrier amplifier, the input end of the peak amplifier, and the input end of the auxiliary amplifier.

[0279] <18>

[0280] according to <14> to <17> An amplifier circuit as described in any one of the above, wherein:

[0281] The bias voltage provided to the auxiliary amplifier is equal to the bias voltage provided to the peak amplifier.

[0282] Industrial Applicability

[0283] The present invention can be widely used in communication devices such as mobile phones as an amplifier circuit arranged in a front end portion supporting multiple frequency bands.

[0284] Description of Reference Numerals

[0285] 1. 1A: high frequency circuit; 2: antenna; 3: RF signal processing circuit (RFIC); 4. 4A: communication device; 10. 10A, 10B, 10C, 10D, 500: amplifier circuit; 11: carrier amplifier; 21: peak amplifier; 22: auxiliary amplifier; 31: low noise amplifier; 41, 42, 43, 44, 45, 46: phase shift circuit; 50: distributor; 61, 62: filter; 71: capacitor; 72: inductor; 73: attenuator; 80: transformer; 100: antenna connection terminal; 110, 130: signal output terminal; 120: signal input terminal; 801: input side coil; 802: output side coil.

Claims

1. An amplifier circuit comprising: Input terminals and output terminals; a carrier amplifier connected between the input terminal and the output terminal; a peak amplifier connected between the input terminal and the output terminal; a first phase shift circuit connected between the carrier amplifier and the output terminal, or connected between the peak amplifier and the output terminal; an auxiliary amplifier connected between the input terminal and an input end or an output end of the carrier amplifier; as well as The second phase shift circuit is connected between the input terminal and the input end or the output end of the carrier amplifier and is configured to invert the phase of the output signal of the auxiliary amplifier at the output terminal relative to the phase of the output signal of the peak amplifier at the output terminal.

2. The amplifier circuit according to claim 1, wherein: The second phase shift circuit comprises: a third phase shift circuit connected between a connection point between the input end of the peak amplifier and the input end of the auxiliary amplifier and the input terminal; and a fourth phase shift circuit connected between the output terminal of the auxiliary amplifier and the input terminal of the carrier amplifier, One end of the first phase shift circuit is connected to the output end of the carrier amplifier, and the other end of the first phase shift circuit is connected to a connection point between the output end of the peak amplifier and the output terminal.

3. The amplifier circuit according to claim 1, wherein: A transformer is also provided, the transformer having an input-side coil and an output-side coil, One end of the first phase shift circuit is connected to the output end of the peak amplifier, One end of the input side coil is connected to the output end of the carrier amplifier, The other end of the input side coil is connected to the other end of the first phase shift circuit. One end of the output side coil is connected to the output terminal, The other end of the output side coil is connected to the ground. The second phase shift circuit comprises: a third phase shift circuit connected between a connection point between the input end of the peak amplifier and the input end of the auxiliary amplifier and the input terminal; and A fourth phase shift circuit is connected between the output end of the auxiliary amplifier and the input end of the carrier amplifier.

4. The amplifier circuit according to claim 2 or 3, wherein: The carrier amplifier, the peak amplifier and the auxiliary amplifier are each an inverting amplifier, The first phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°. The third phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°. The fourth phase shift circuit is a phase shift circuit that advances the input signal by 90°.

5. The amplifier circuit according to any one of claims 2 to 4, wherein: An attenuator is also provided, and the attenuator is connected between a connection point between an input end of the carrier amplifier and the fourth phase shift circuit and an output end of the auxiliary amplifier.

6. The amplifier circuit according to any one of claims 2 to 4, wherein: The gain of the auxiliary amplifier is lower than the gain of the peak amplifier.

7. The amplifier circuit according to claim 1, wherein: The second phase shift circuit is connected between the connection point between the input terminal and the output end of the auxiliary amplifier and the input end of the carrier amplifier. One end of the first phase shift circuit is connected to the output end of the carrier amplifier, and the other end of the first phase shift circuit is connected to a connection point between the output end of the peak amplifier and the output terminal.

8. The amplifier circuit according to claim 1, wherein: A transformer is also provided, the transformer having an input-side coil and an output-side coil, One end of the first phase shift circuit is connected to the output end of the peak amplifier, One end of the input side coil is connected to the output end of the carrier amplifier, The other end of the input side coil is connected to the other end of the first phase shift circuit. One end of the output side coil is connected to the output terminal, The other end of the output side coil is connected to the ground. The second phase shift circuit is connected between a connection point between the input terminal and the output end of the auxiliary amplifier and an input end of the carrier amplifier.

9. The amplifier circuit according to claim 7 or 8, wherein: The carrier amplifier, the peak amplifier and the auxiliary amplifier are each an inverting amplifier, The first phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°. The second phase shift circuit is a phase shift circuit that advances the input signal by 90°.

10. The amplifier circuit according to any one of claims 7 to 9, wherein: An attenuator is further provided, and the attenuator is connected between a connection point between the input terminal and the output end of the auxiliary amplifier and the output end of the auxiliary amplifier.

11. The amplifier circuit according to any one of claims 7 to 9, wherein: The gain of the auxiliary amplifier is lower than the gain of the peak amplifier.

12. The amplifier circuit according to any one of claims 1 to 11, wherein: A power divider is further provided, and the power divider is connected between the input terminal and the input end of the carrier amplifier, the input end of the peak amplifier, and the input end of the auxiliary amplifier.

13. The amplifier circuit according to any one of claims 1 to 12, wherein: The bias voltage provided to the auxiliary amplifier is equal to the bias voltage provided to the peak amplifier.

14. An amplifier circuit comprising: Input terminals and output terminals; a carrier amplifier connected between the input terminal and the output terminal; a peak amplifier connected between the input terminal and the output terminal; A first phase shift circuit connected between the output end of the carrier amplifier and the output terminal; an auxiliary amplifier connected between the input terminal and an input end of the carrier amplifier; as well as The second phase shift circuit is connected between a connection point between the input terminal and the output end of the auxiliary amplifier and the input end of the carrier amplifier.

15. An amplifier circuit comprising: Input terminals and output terminals; a carrier amplifier connected between the input terminal and the output terminal; a peak amplifier connected between the input terminal and the output terminal; a first phase shifting circuit and a second phase shifting circuit; an auxiliary amplifier connected between the input terminal and an input end of the carrier amplifier; as well as A transformer having an input side coil and an output side coil, Wherein, one end of the first phase shift circuit is connected to the output end of the peak amplifier, One end of the input side coil is connected to the output end of the carrier amplifier, The other end of the input side coil is connected to the other end of the first phase shift circuit. One end of the output side coil is connected to the output terminal, The other end of the output side coil is connected to the ground. One end of the second phase shift circuit is connected to a connection point between the input terminal and the output end of the auxiliary amplifier. The other end of the second phase shift circuit is connected to the input end of the carrier amplifier.

16. The amplifier circuit according to claim 14 or 15, wherein: The carrier amplifier, the peak amplifier and the auxiliary amplifier are each an inverting amplifier, The first phase shift circuit is a phase shift circuit that causes the input signal to lag by 90°. The second phase shift circuit is a phase shift circuit that advances the input signal by 90°.

17. The amplifier circuit according to any one of claims 14 to 16, wherein: A power divider is further provided, and the power divider is connected between the input terminal and the input end of the carrier amplifier, the input end of the peak amplifier, and the input end of the auxiliary amplifier.

18. The amplifier circuit according to any one of claims 14 to 17, wherein: The bias voltage provided to the auxiliary amplifier is equal to the bias voltage provided to the peak amplifier.

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