High-frequency power amplifier

Abstract

Provided is a high-frequency power amplifier having a sequential LMBA configuration and capable of obtaining broadband characteristics. The hybrid coupler has first to fourth ports. The input signal distributor distributes a high-frequency first input signal into two second signals. The peak amplifier includes two first amplifiers, amplifies each of two high-frequency signals obtained by distributing one second signal, and outputs of the two first amplifiers are coupled to the first and second ports. The carrier amplifier includes a synthesizer and two second amplifiers, and amplifies each of two high-frequency signals obtained by distributing another second signal. The voltage level of the first input signal when the output current of the peak amplifier rises is higher than the voltage level of the first input signal when the output current of the carrier amplifier rises. The high-frequency signals input to the first and second ports are combined and output from the fourth port, and the load impedance of the first amplifier varies in accordance with the current level of the high-frequency signal input from the carrier amplifier to the third port.

Description

Technical Field

[0001] This invention relates to high-frequency power amplifiers. Background Technology

[0002] The high-frequency power amplifier used in the transmitting section of wireless communication is the circuit that consumes the most power in wireless communication circuits. In order to suppress the power consumption of wireless communication circuits, there is a need for techniques to improve the power-added efficiency of high-frequency power amplifiers. As a high-efficiency technique to improve power-added efficiency, a load-modulated balanced amplifier (LMBA) has been proposed. The LMBA includes a balanced amplifier, a control amplifier, and a hybrid coupler, and modulates the load impedance of the balanced amplifier by the output of the control amplifier.

[0003] As one type of LMBA, a sequential LMBA (Non-Patent Document 1) was proposed. In the sequential LMBA disclosed in Non-Patent Document 1, the balanced amplifier is operated with a Class C bias, and the control amplifier is operated with a Class B bias. In Non-Patent Document 1, the balanced amplifier is referred to as the peak amplifier, and the control amplifier is referred to as the carrier amplifier.

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-patent document 1: J. Pang, "Analysis and Design of Highly EfficientWideband RF-Input Sequential Load Modulated Balanced Power Amplifier", IEEETrans. on Microwave Theory and Techn., Vol. 68, No. 5, pp.1741-1753, May 2020

[0007] In an ideal hybrid coupler, the high-frequency signal leakage from the peak amplifier to the output node of the carrier amplifier through the hybrid coupler is negligible, and the load impedance of the carrier amplifier remains unchanged. However, in practical hybrid couplers, high-frequency signal leakage from the peak amplifier to the output node of the carrier amplifier through the hybrid coupler is possible. Due to this leakage, the load impedance of the carrier amplifier varies significantly.

[0008] In a peak amplifier with Class C bias, such as Figure 3C As shown, the load impedance Z increases with the increase of the input signal level. BAThe frequency drops sharply. If there is high-frequency signal leakage from the peak amplifier to the output node of the carrier amplifier, the load impedance of the carrier amplifier will vary with frequency near the saturation level of the carrier amplifier's output power. This frequency dependence makes it difficult to achieve good frequency characteristics. Summary of the Invention

[0009] The problem the invention aims to solve

[0010] The purpose of this invention is to provide a high-frequency power amplifier with a sequential LMBA structure that can achieve broadband characteristics.

[0011] Technical solutions for solving the problem

[0012] According to one aspect of the present invention, a high-frequency power amplifier is provided, comprising:

[0013] A hybrid coupler having port 1, port 2, port 3, and port 4;

[0014] The input signal distributor divides the high-frequency first input signal into two second input signals;

[0015] A peak amplifier comprising two first amplifiers, each amplifying two high-frequency signals obtained by distributing a second input signal, wherein the outputs of each of the two first amplifiers are coupled to both the first port and the second port; and

[0016] The carrier amplifier includes two second amplifiers and a synthesizer. The two second amplifiers amplify two high-frequency signals obtained by distributing another second input signal. The synthesizer combines the high-frequency signals amplified by the two second amplifiers and inputs them to the third port.

[0017] The voltage level of the first input signal when the output current of the peak amplifier rises is higher than the voltage level of the first input signal when the output current of the carrier amplifier rises.

[0018] The hybrid coupler has the following structure: it combines high-frequency signals input to the first port and the second port and outputs them from the fourth port; the load impedance of the two first amplifiers of the peak amplifier varies according to the current level of the high-frequency signal input from the carrier amplifier to the third port.

[0019] Invention Effects

[0020] The carrier amplifier contains two secondary amplifiers, which combine the high-frequency signals amplified by the two secondary amplifiers and input them to the hybrid coupler. Therefore, the carrier amplifier is less susceptible to leakage from the output signal of the peak amplifier. As a result, broadband characteristics can be obtained. Attached Figure Description

[0021] Figure 1 This is a block diagram of a high-frequency power amplifier based on the first embodiment.

[0022] Figure 2 This is a schematic equivalent circuit diagram used to illustrate the operation of the hybrid coupler 30.

[0023] Figure 3A This is a coordinate graph showing the relationship between the input voltage and output current of peak amplifier 10 and carrier amplifier 20. Figure 3B This is a coordinate graph showing the relationship between the input voltage and output voltage of peak amplifier 10 and carrier amplifier 20. Figure 3C This is a coordinate graph showing the relationship between the input voltage and the resistive component of the load impedance of peak amplifier 10 and carrier amplifier 20. Figure 3D It is a coordinate graph showing the relationship between input power and power-added efficiency.

[0024] Figure 4 This is a schematic top view of the hybrid coupler 30 used in a high-frequency power amplifier based on a variation of the first embodiment.

[0025] Figure 5 This is a schematic perspective view of a hybrid coupler 30 used in a high-frequency power amplifier based on another variation of the first embodiment.

[0026] Figure 6 This is an equivalent circuit diagram of the hybrid coupler 30 used in a high-frequency power amplifier based on yet another variation of the first embodiment.

[0027] Figure 7 This is a block diagram of a high-frequency power amplifier based on the second embodiment.

[0028] Figure 8 This is a block diagram showing the bias control state of the bias control unit 60 when performing bias control in ultra-low power mode.

[0029] Figure 9 This is a block diagram showing the bias control state of the bias control unit 60 when it performs bias control in the first low power mode.

[0030] Figure 10 This is a block diagram showing the bias control state of the bias control unit 60 when it performs bias control in the second low power mode.

[0031] Figure 11 This is a schematic diagram showing the positional relationship of the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 based on the third embodiment of the high-frequency power amplifier.

[0032] Figure 12 This is a schematic diagram showing the positional relationship of the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 of the high-frequency power amplifier based on the comparative example.

[0033] Figure 13 This is a schematic diagram showing the positional relationship of the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 of the high-frequency power amplifier based on a modified example of the third embodiment.

[0034] Figure 14 This is a block diagram of a communication device based on the fourth embodiment.

[0035] Explanation of reference numerals in the attached figures

[0036] 10: Peak amplifier;

[0037] 11: First Distributor;

[0038] 12A, 12B: Amplifier 1;

[0039] 20: Carrier amplifier;

[0040] 21: Second distributor;

[0041] 22A, 22B: Second amplifier;

[0042] 23: Synthesizer;

[0043] 30: Hybrid coupler;

[0044] 31A, 31B, 31C, 31D: Transmission lines;

[0045] 32A, 32B: Flat panels;

[0046] 33A, 33B: Inductors;

[0047] 33C, 33D: Capacitors;

[0048] 40: Input signal distributor;

[0049] 50: Driver stage amplifier;

[0050] 51, 52, 53: Impedance matching circuit;

[0051] 60: Bias control unit;

[0052] 70: substrate;

[0053] 80: Sending system;

[0054] 81: High-frequency power amplifier;

[0055] 82: First switch;

[0056] 83: Filter circuit;

[0057] 84: Second switch;

[0058] 90: Transceiver IC;

[0059] 91: Multiplexer;

[0060] 92: Antenna. Detailed Implementation

[0061] [First Embodiment]

[0062] Reference Figures 1 to 3D The accompanying drawings illustrate a high-frequency power amplifier based on the first embodiment.

[0063] Figure 1 This is a block diagram of a high-frequency power amplifier based on the first embodiment. The high-frequency power amplifier based on the first embodiment includes a peak amplifier 10, a carrier amplifier 20, a hybrid coupler 30, and an input signal distributor 40. Hereinafter, the high-frequency power amplifier based on the first embodiment and its peripheral circuitry will be described.

[0064] From input terminal T in The input high-frequency signal is fed into the driver amplifier 50 via impedance matching circuit 51. This high-frequency signal is a radio frequency signal modulated by a given communication method. The driver amplifier 50 amplifies the input high-frequency signal and outputs the first input signal RF1. The first input signal RF1 amplified by the driver amplifier 50 is then fed into the input signal distributor 40.

[0065] Input signal distributor 40 distributes the first input signal RF1 and outputs two second input signals RF2a and RF2b. The input signal distributor 40 can be, for example, a 3dB coupler utilizing a coupled transmission line, a Wilkinson type distributor, etc. For example, the signal levels of each of the second input signals RF2a and RF2b are 3dB lower than the signal level of the first input signal, and they have a 90° phase difference. One second input signal RF2a is input to the peak amplifier 10, and the other second input signal RF2b is input to the carrier amplifier 20. Alternatively, the phase difference between the two second input signals RF2a and RF2b can be a phase difference other than 90°.

[0066] Peak amplifier 10 includes two first amplifiers 12A and 12B that amplify two high-frequency signals obtained by distributing a second input signal RF2a. The first amplifiers 12A and 12B are constructed, for example, by heterojunction bipolar transistors (HBTs). For example, a first distributor 11 distributes the second input signal RF2a into two high-frequency signals. The two high-frequency signals have equal signal levels and a 90° phase difference. The first distributor 11 can, for example, use a 3dB coupler utilizing a coupled transmission line. The first amplifiers 12A and 12B are each Class C biased.

[0067] The carrier amplifier 20 includes two second amplifiers 22A and 22B that amplify two high-frequency signals obtained by distributing another second input signal RF2b. The second amplifiers 22A and 22B are constructed, for example, by heterojunction bipolar transistors (HBTs). For example, the second distributor 21 distributes the second input signal RF2b into two high-frequency signals. The signal levels of these two high-frequency signals are equal, and they have a 90° phase difference. The second distributor 21 can, for example, use a 3dB coupler utilizing a coupled transmission line. The second amplifiers 22A and 22B are each class AB biased. Alternatively, the second amplifiers 22A and 22B can also be class B biased.

[0068] Carrier amplifier 20 combines and outputs two high-frequency signals amplified by two second amplifiers 22A and 22B, respectively. For example, synthesizer 23 combines two high-frequency signals amplified by two second amplifiers 22A and 22B, respectively. As synthesizer 23, for example, a 3dB coupler utilizing a coupled transmission line can be used.

[0069] The hybrid coupler 30 consists of a main line and a secondary line that are electromagnetically coupled to each other. Let one end of the main line be called port 1 P1 and the other end be called port 4 P4. Let the end of the secondary line on the port 1 P1 side be called port 3 P3 and the end on the port 4 P4 side be called port 2 P2.

[0070] The outputs of the two first amplifiers 12A and 12B are coupled to ports P1 and P2 of the hybrid coupler 30, respectively. The output of the carrier amplifier 20, i.e., the output of the synthesizer 23, is coupled to port 3 of the hybrid coupler 30 via impedance matching circuit 52. Port P4 of the hybrid coupler 30 is coupled to the output terminal T via impedance matching circuit 53. out coupling.

[0071] The high-frequency signals input to port 1 (P1) and port 2 (P2) are combined and output from port 4 (P4). The high-frequency signal input to port 3 (P3) is output from port 4 (P4). That is, the high-frequency signal output from port 4 (P4) has a power equal to the sum of the power of the high-frequency signals input to port 1 (P1), port 2 (P2), and port 3 (P3). The load impedance of the two first amplifiers 12A and 12B of the peak amplifier 10 varies according to the current level of the high-frequency signal input from the carrier amplifier 20 to port 3 (P3). More specifically, the load impedance of the two first amplifiers 12A and 12B of the peak amplifier 10 varies according to the ratio of the current level of the high-frequency signal input from the carrier amplifier 20 to port 3 (P3) to the current level of the high-frequency signals input from the peak amplifier 10 to ports 1 (P1) and 2 (P2).

[0072] Next, refer to Figure 2 The operation of the hybrid coupler 30 is described in more detail.

[0073] Figure 2 This is a simplified equivalent circuit diagram used to illustrate the operation of the hybrid coupler 30. The two first amplifiers 12A and 12B of the peak amplifier 10 are considered to generate currents -I respectively. BA jI BA The current source. The carrier amplifier 20 is considered to generate a current -I at the point where it flows into port P3. CSP e jφ The current source. Here, j is the imaginary unit, and φ is the phase offset. Additionally, the current -I CSP e jφ This represents the current output from the carrier amplifier 20 and after passing through the impedance matching circuit 52.

[0074] A load RL is connected to port 4 (P4). The current flowing from the load RL into port 4 (P4) is labeled as -I. L The voltages generated at port 1 (P1), port 2 (P2), port 3 (P3), and port 4 (P4) are respectively labeled as V. BA2 V BA1 V CSP V LThe first amplifiers 12A and 12B, and the load impedance representing the current source of the carrier amplifier 20, are respectively labeled Z. BA2 Z BA1 Z CSP .

[0075] The output current and output voltage of each current source can be expressed using the impedance matrix of the hybrid coupler 30 with the following relationship.

[0076] [Mathematical Expression 1]

[0077] …(1)

[0078] Here, Z0 is the characteristic impedance of the hybrid coupler 30.

[0079] If equation (1) is expanded, then the two first amplifiers 12A of the peak amplifier 10 ( Figure 1 The load impedance Z BA1 Z BA2 It can be represented by the following formula.

[0080] [Mathematical Expression 2]

[0081] …(2)

[0082] The load impedance Z of carrier amplifier 20 CSP It can be represented by the following formula.

[0083] [Mathematical Expression 3]

[0084] …(3)

[0085] According to equation (2), the load impedance Z of the two first amplifiers 12A and 12B of the peak amplifier 10 is... BA1 Z BA2 Equal, can be obtained from the output current I from carrier amplifier 20. CSP And the phase offset φ is controlled. On the other hand, the load impedance Z of the carrier amplifier 20 CSP fixed.

[0086] Figure 3A This is a coordinate graph showing the relationship between the input voltage and output current of peak amplifier 10 and carrier amplifier 20. The input voltage is represented by a normalized value on the horizontal axis, and the output current is represented by a normalized value on the vertical axis. Furthermore, the normalized value of the maximum input voltage is defined as 1, and the output current I of peak amplifier 10 is... BA The normalized value of the maximum value is defined as 1. Figure 3A The solid lines in the coordinate graph shown represent the first amplifiers 12A and 12B of the peak amplifier 10. Figure 1 Their respective output currents I BA The dashed line indicates the output current I of the carrier amplifier 20. CSP Hereinafter, the normalized value of the input voltage will sometimes be referred to as "input voltage", and the normalized value of the output current will sometimes be referred to as "output current".

[0087] The output current I of the peak amplifier 10 with Class C bias BA The voltage level of the second input signal RF2a during its rise is higher than the voltage level of the second input signal RF2b during the rise of the output current of the class-AB biased carrier amplifier 20. For example, the output current I of the class-AB biased carrier amplifier 20... CSP Starting from the point where the input voltage is 0, the output current I of the class-C biased peak amplifier 10 rises. BA The voltage starts to rise from the point when the input voltage is 0.5.

[0088] The carrier amplifier 20 is designed to operate at the output current I of the peak amplifier 10. BA Saturation occurs under rising input voltage. Therefore, in the range of input voltage above 0 and below 0.5, the output current I... CSP The output current I increases approximately linearly relative to the input voltage. Within the range of input voltage above 0.5 and below 1, the output current I... CSP It is roughly fixed.

[0089] The output current I of carrier amplifier 20 CSP After saturation, the output current of peak amplifier 10 increases, thus maintaining the linearity of the overall output current of the high-frequency power amplifier.

[0090] Figure 3B This is a coordinate graph showing the relationship between the input and output voltages of peak amplifier 10 and carrier amplifier 20. The input voltage is represented by a normalized value on the horizontal axis, and the output voltage is represented by a normalized value on the vertical axis. Here, the output voltage V of peak amplifier 10 is... BA The normalized value of the maximum value is defined as 1. Figure 3B The solid line in the coordinate graph shows the output voltage V of peak amplifier 10. BA The dashed line indicates the output voltage V of the carrier amplifier 20. CSP Hereinafter, the normalized value of the output voltage will sometimes be referred to simply as "output voltage".

[0091] The output voltage V of peak amplifier 10 BAThe output voltage V increases linearly relative to the input voltage in the range of 0 to 0.5, and also increases linearly relative to the input voltage in the range of 0.5 to 1. The output voltage V in the range of 0.5 to 1... BA The slope of the output voltage V is greater than or equal to the input voltage in the range of 0 to 0.5. BA The slope is gentle.

[0092] The output voltage V of carrier amplifier 20 CSP It increases linearly in the range of input voltage above 0 and below 0.5, and is fixed in the range of input voltage above 0.5 and below 1.

[0093] Figure 3C This is a coordinate graph showing the relationship between the input voltage of peak amplifier 10 and carrier amplifier 20 and the resistive component of the load impedance. The input voltage is represented by a normalized value on the horizontal axis, and the resistive component of the load impedance is represented by a normalized value on the vertical axis. The normalized value is defined as 1 when the load impedance is equal to the characteristic impedance Z0 of the hybrid coupler 30. Figure 3C The solid line in the coordinate graph shows the load impedance Z of peak amplifier 10. BA The resistive component is shown by the dashed line, which represents the load impedance Z of the carrier amplifier 20. CSP The resistive component.

[0094] As shown in equation (3), the load impedance Z of carrier amplifier 20 CSP The load impedance Z of peak amplifier 10 is fixed and its normalized value is 1. BA It can be expressed by equation (2), which becomes infinitely large when the input voltage is 0.5, and decreases as the input voltage increases in the range of input voltage above 0.5 and below 1.

[0095] Figure 3D This is a graph showing the relationship between input power and power-added efficiency. On the horizontal axis, the ratio of input power to the maximum input power (input power ratio) is expressed in dB, and on the vertical axis, power-added efficiency is expressed in % (%).

[0096] Similar to previous Doherty amplifiers, high efficiency was achieved in the power back-off region near the input power ratio of -6dB.

[0097] Next, the superior effects of the first embodiment will be explained.

[0098] In the conventional sequential LMBA (Non-Patent Document 1), the carrier amplifier 20 was not configured as a balanced amplifier. If leakage of high-frequency signals occurs from the peak amplifier 10 to the carrier amplifier 20, the load impedance of the carrier amplifier 20 varies significantly. In particular, in a peak amplifier with Class C bias, the load impedance drops sharply with increasing input signal level. Therefore, near the point where the output power of the carrier amplifier reaches saturation, the load impedance of the carrier amplifier varies frequency-dependently. This frequency dependence makes it difficult to achieve good frequency characteristics.

[0099] In the first embodiment, the carrier amplifier 20 is configured as a balanced amplifier structure, thus suppressing the variation in the characteristics of the carrier amplifier 20 caused by leakage of high-frequency signals from the peak amplifier 10 to the carrier amplifier 20. Therefore, broadband characteristics can be easily obtained.

[0100] Furthermore, like a reference Figure 3A As explained, after the output current of the carrier amplifier 20 saturates, the output current of the peak amplifier 10 rises, thus maintaining the linearity of the overall output current of the high-frequency power amplifier. Furthermore, as referenced... Figure 3D As explained, high efficiency can be achieved in the rollback region.

[0101] Next, refer to Figure 4 , Figure 5 ,as well as Figure 6 A high-frequency power amplifier based on a variation of the first embodiment will be described. In the first embodiment, a 3dB coupler consisting of a coupling transmission line is used as the hybrid coupler 30. In the variation described below, other couplers are used as the hybrid coupler 30.

[0102] Figure 4 This is a schematic top view of a hybrid coupler 30 used in a high-frequency power amplifier based on a variation of the first embodiment. In this variation, a branch-line coupler is used as the hybrid coupler 30.

[0103] The hybrid coupler 30 consists of four transmission lines 31A, 31B, 31C, and 31D, each with a length equivalent to 1 / 4 wavelength, arranged along the outer perimeter of a square. As an example, transmission lines 31A, 31B, 31C, and 31D are arranged in a clockwise direction. The characteristic impedance of transmission lines 31A and 31C is Z0, and the characteristic impedance of transmission lines 31B and 31D is Z0 / 2. 1 / 2 .

[0104] The connection point between transmission lines 31A and 31B corresponds to port 1 P1, the connection point between transmission lines 31A and 31D corresponds to port 2 P2, the connection point between transmission lines 31C and 31D corresponds to port 3 P3, and the connection point between transmission lines 31B and 31C corresponds to port 4 P4.

[0105] Figure 5 This is a schematic perspective view of a hybrid coupler 30 used in a high-frequency power amplifier based on another variation of the first embodiment. In this variation, a parallel planar coupler is used as the hybrid coupler 30.

[0106] The hybrid coupler 30 includes rectangular conductive plates 32A and 32B that are parallel to each other. One corner of plate 32A corresponds to port 1 P1, and the opposite corner corresponds to port 4 P4. The corner of plate 32B that overlaps with the corner of port 1 P1 corresponds to port 3 P3, and the opposite corner in the long side direction corresponds to port 2 P2.

[0107] Figure 6 This is an equivalent circuit diagram of the hybrid coupler 30 used in a high-frequency power amplifier based on yet another variation of the first embodiment. In this variation, a lumped parameter coupler is used as the hybrid coupler 30.

[0108] The hybrid coupler 30 includes a pair of inductors 33A and 33B, and capacitors 33C and 33D that are magnetically coupled to each other. One end of inductor 33A corresponds to port 3 P3, and the other end corresponds to port 2 P2. The end of inductor 33B on the port 3 P3 side corresponds to port 1 P1, and the opposite end corresponds to port 4 P4. Capacitor 33C is connected between port 1 P1 and port 3 P3, and capacitor 33D is connected between port 2 P2 and port 4 P4.

[0109] like Figure 4 , Figure 5 , Figure 6 As shown, as a hybrid coupler 30, branch line couplers, parallel plate couplers, lumped parameter couplers, etc. can also be used.

[0110] [Second Embodiment]

[0111] Next, refer to Figures 7 to 10 The accompanying drawings illustrate a high-frequency power amplifier based on the second embodiment. Hereinafter, regarding the reference... Figures 1 to 3D The accompanying drawings illustrate the common structure of the high-frequency power amplifier based on the first embodiment, and the description is omitted.

[0112] Figure 7This is a block diagram of a high-frequency power amplifier based on the second embodiment. In the first embodiment ( Figure 1 In the first embodiment, a Class C bias is provided for the peak amplifier 10, and a Class AB bias is provided for the carrier amplifier 20. In contrast, in the second embodiment, the bias control unit 60 has multiple control modes, each performing bias control that alters the bias of the peak amplifier 10 and the carrier amplifier 20. The bias control unit 60 controls the bias, for example, using a control mode selected from an extremely low power mode, a first low power mode, and a second low power mode. These control modes can be selected via user commands (instructions).

[0113] Figure 8 This is a block diagram illustrating the bias control state of the bias control unit 60 when performing bias control in ultra-low power mode. In ultra-low power mode, the bias control unit 60 provides a Class AB bias to one of the second amplifiers 22A of the carrier amplifier 20, but does not provide a bias to the other second amplifier 22B. That is, the second amplifier 22B is turned off and does not perform amplification. Furthermore, neither of the two first amplifiers 12A and 12B of the peak amplifier 10 is biased. That is, the peak amplifier 10 is turned off and does not perform amplification. Figure 8 In the diagram, the amplifier in the off state is highlighted with a shading. This will be explained in the following description. Figure 9 , Figure 10 Similarly, the amplifier in the off state is also highlighted with a shading.

[0114] Figure 9 This is a block diagram showing the bias control state of the bias control unit 60 when performing bias control in the first low-power mode. In the first low-power mode, the bias control unit 60 provides Class AB bias to the two second amplifiers 22A of the carrier amplifier 20, but does not provide bias to either of the two first amplifiers 12A and 12B of the peak amplifier 10.

[0115] Figure 10 This is a block diagram illustrating the bias control state of the bias control unit 60 when performing bias control in the second low-power mode. In the second low-power mode, the bias control unit 60 provides a Class AB bias to one of the second amplifiers 22A of the carrier amplifier 20 and a Class C bias to the other second amplifier 22B. The two second amplifiers 22A and 22B operate as Dougherty amplifiers. No bias is provided to either of the two first amplifiers 12A and 12B of the peak amplifier 10.

[0116] Next, the superior effects of the second embodiment will be explained.

[0117] In the second embodiment, a portion of the amplifiers are turned off according to the control mode. Therefore, as a whole, the reactive current decreases, and power-added efficiency can be improved. Furthermore, the selection of which control mode to use is determined solely by the maximum signal level of the first input signal RF1.

[0118] The effect of reducing reactive current is maximized when the control mode is in the ultra-low power mode. Furthermore, the transistor constituting the carrier amplifier 20 is smaller than the transistor constituting the peak amplifier 10. When the control mode is in the first low power mode or the second low power mode, a greater effect of reducing reactive current can be achieved by turning off the larger transistor in the peak amplifier 10.

[0119] When the control mode is the second low power mode ( Figure 10 When the carrier amplifier 20 operates as a Dougherty power amplifier, it can further improve the power-added efficiency compared to the case of the first low-power mode.

[0120] [Embodiment 3]

[0121] Next, refer to Figure 11 A high-frequency power amplifier based on the third embodiment will be described below. Hereinafter, regarding the reference... Figures 1 to 3D The common structure of the high-frequency power amplifier based on the first embodiment, as illustrated in the accompanying drawings, is omitted from the description.

[0122] Figure 11 This is a schematic diagram showing the positional relationship of the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 based on the third embodiment of the high-frequency power amplifier. In the first embodiment, there are no particular limitations regarding their positional relationship.

[0123] In the third embodiment, the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 are formed on a common substrate 70. Viewed from above, the two second amplifiers 22A and 22B of the carrier amplifier 20 are positioned between the two first amplifiers 12A and 12B of the peak amplifier 10. More specifically, one first amplifier 12A, one second amplifier 22A, another second amplifier 22B, and another first amplifier 12B are arranged in a row. Alternatively, the arrangement order of one second amplifier 22A and another second amplifier 22B can be reversed.

[0124] The driver stage amplifier 50 is positioned separately in the direction of the column intersection of the first amplifiers 12A, 12B and the second amplifiers 22A, 22B.

[0125] Next, in conjunction with Figure 12 The superior effects of the third embodiment will be explained while comparing the comparative examples shown.

[0126] Figure 12 This is a schematic diagram showing the positional relationship of the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 in the high-frequency power amplifier based on the comparative example. In the comparative example, the second amplifiers 22A and 22B of the carrier amplifier 20 and the first amplifiers 12A and 12B of the peak amplifier 10 are arranged in a row.

[0127] If we consider one of the first amplifiers 12A in the peak amplifier 10, then a first amplifier 12B and a second amplifier 22B are arranged on both sides of it. If we consider the other first amplifier 12B, then a first amplifier 12A is arranged only on one side. Therefore, when the first amplifiers 12A and 12B, and the second amplifiers 22A and 22B generate heat during the operation of the high-frequency power amplifier, a difference in thermal effect occurs between the two first amplifiers 12A and 12B. Similarly, a difference in thermal effect also occurs between the two second amplifiers 22A and 22B in the carrier amplifier 20. This difference in thermal effect becomes a cause of malfunction of the high-frequency power amplifier.

[0128] In the third embodiment, if considering each of the two first amplifiers 12A and 12B of the peak amplifier 10, the second amplifiers 22A and 22B are arranged only on one side. Furthermore, if considering one of the second amplifiers 22A of the carrier amplifier 20, the first amplifier 12A is arranged on one side and the second amplifier 22B is arranged on the other side. Even when considering the other second amplifier 22B, the first amplifier 12B is arranged on one side and the second amplifier 22A is arranged on the other side.

[0129] Therefore, the thermal effects on the first amplifiers 12A and 12B of the peak amplifier 10 are approximately equal, and the thermal effects on the two second amplifiers 22A and 22B of the carrier amplifier 20 are also approximately equal. Differences in thermal effects are unlikely to occur between the first amplifiers 12A and 12B of the peak amplifier 10, and also unlikely to occur between the two second amplifiers 22A and 22B of the carrier amplifier 20. Therefore, malfunctions in the high-frequency power amplifier caused by differences in thermal effects become less likely.

[0130] Next, refer to Figure 13A high-frequency power amplifier based on a modified example of the third embodiment will be described. Figure 13 This is a schematic diagram showing the positional relationship of the two first amplifiers 12A and 12B of the peak amplifier 10, the two second amplifiers 22A and 22B of the carrier amplifier 20, and the driver stage amplifier 50 of the high-frequency power amplifier based on a modified example of the third embodiment.

[0131] In the third embodiment ( Figure 11 In the original diagram, when viewed from above the substrate 70, the two second amplifiers 22A and 22B of the carrier amplifier 20 are positioned between the two first amplifiers 12A and 12B of the peak amplifier 10. In contrast, in this modified example, the positions of the peak amplifier 10 and the carrier amplifier 20 are reversed. That is, the two first amplifiers 12A and 12B of the peak amplifier 10 are positioned between the two second amplifiers 22A and 22B of the carrier amplifier 20.

[0132] exist Figure 13 The variant shown is also similar to the third embodiment ( Figure 11 Similarly, it becomes less likely to cause malfunctions in high-frequency power amplifiers due to different thermal effects.

[0133] [Example 4]

[0134] Next, refer to Figure 14 The communication device based on the fourth embodiment will be described. Figure 14 This is a block diagram of a communication device based on the fourth embodiment. The communication device based on the fourth embodiment includes a transceiver IC 90, multiple transmitting systems 80, a multiplexer 91, and an antenna 92. Each of the multiple transmitting systems 80 includes a high-frequency power amplifier 81, a first switch 82, multiple filter circuits 83, and a second switch 84. The high-frequency power amplifier 81 can be a high-frequency power amplifier based on the first, second, or third embodiment.

[0135] The transceiver IC 90 inputs the high-frequency signal to be transmitted to the high-frequency power amplifier 81 of each of the multiple transmitting systems 80. The high-frequency signal amplified by the high-frequency power amplifier 81 is input to a filter circuit 83 selected by the first switch 82. The high-frequency signal passing through the filter circuit 83 is transmitted to the antenna 92 ​​via the second switch 84 and the multiplexer 91.

[0136] Next, the superior effects of the fourth embodiment will be explained.

[0137] In the fourth embodiment, a high-frequency power amplifier based on the first, second, or third embodiment is used as the high-frequency power amplifier 81, thus maintaining the linearity of the input-output characteristics and achieving high efficiency in the fallback region. Furthermore, broadband characteristics can be easily obtained.

[0138] The above embodiments are illustrative examples, and it is self-evident that partial substitutions or combinations of the structures shown in different embodiments are possible. The same effects of the same structures based on multiple embodiments will not be mentioned in each embodiment individually. Furthermore, the present invention is not limited to the above embodiments. For example, it will be apparent to those skilled in the art that various changes, modifications, combinations, etc., are possible.

[0139] Based on the embodiments described in this specification, the following invention is disclosed.

[0140] <1>

[0141] A high-frequency power amplifier, comprising:

[0142] A hybrid coupler having port 1, port 2, port 3, and port 4;

[0143] The input signal distributor divides the high-frequency first input signal into two second input signals;

[0144] A peak amplifier comprising two first amplifiers, each amplifying two high-frequency signals obtained by distributing a second input signal, wherein the outputs of each of the two first amplifiers are coupled to both the first port and the second port; and

[0145] The carrier amplifier includes two second amplifiers and a synthesizer. The two second amplifiers amplify two high-frequency signals obtained by distributing another second input signal. The synthesizer combines the high-frequency signals amplified by the two second amplifiers and inputs them to the third port.

[0146] The voltage level of the first input signal when the output current of the peak amplifier rises is higher than the voltage level of the first input signal when the output current of the carrier amplifier rises.

[0147] The hybrid coupler has the following structure: it combines high-frequency signals input to the first port and the second port and outputs them from the fourth port; the load impedance of the two first amplifiers of the peak amplifier varies according to the current level of the high-frequency signal input from the carrier amplifier to the third port.

[0148] <2>

[0149] According to the high-frequency power amplifier described in <1>, wherein,

[0150] When the voltage level of the first input signal is increased, the output current of the carrier amplifier saturates at the point in time when the output current of the peak amplifier rises.

[0151] <3>

[0152] According to the high-frequency power amplifier described in <1> or <2>, wherein,

[0153] The high-frequency power amplifier further includes a bias control unit for controlling the bias of the carrier amplifier and the peak amplifier.

[0154] The bias control unit has multiple control modes, and the bias of the carrier amplifier and the peak amplifier is different according to each control mode.

[0155] <4>

[0156] According to the high-frequency power amplifier described in <3>, wherein...

[0157] In one of the multiple control modes, the bias control unit causes the two second amplifiers of the carrier amplifier to operate as Dougherty amplifiers.

[0158] <5>

[0159] According to the high-frequency power amplifier described in <3> or <4>, wherein,

[0160] In one of the multiple control modes, the bias control unit provides a bias to the two first amplifiers of the peak amplifier that does not generate output current, regardless of the voltage level of the first input signal.

[0161] <6>

[0162] The high-frequency power amplifier according to any one of <3> to <5>, wherein,

[0163] In one of the multiple control modes, the bias control unit provides a bias to one of the two second amplifiers of the carrier amplifier that does not generate output current regardless of the voltage level of the first input signal, and provides a Class AB or Class B bias to the other second amplifier.

[0164] <7>

[0165] The high-frequency power amplifier according to any one of <1> to <6>, wherein,

[0166] The two first amplifiers of the peak amplifier and the two second amplifiers of the carrier amplifier are formed on a common substrate.

[0167] One of the two first amplifiers and one of the two second amplifiers is positioned to be sandwiched between the other.

Claims

1. A high-frequency power amplifier, comprising: A hybrid coupler having port 1, port 2, port 3, and port 4; The input signal distributor divides the high-frequency first input signal into two second input signals; A peak amplifier comprising two first amplifiers, each amplifying two high-frequency signals obtained by distributing a second input signal, and the outputs of each of the two first amplifiers being coupled to the first port and the second port; as well as The carrier amplifier includes two second amplifiers and a synthesizer. The two second amplifiers amplify two high-frequency signals obtained by distributing another second input signal. The synthesizer combines the high-frequency signals amplified by the two second amplifiers and inputs them to the third port. The voltage level of the first input signal when the output current of the peak amplifier rises is higher than the voltage level of the first input signal when the output current of the carrier amplifier rises. The hybrid coupler has the following structure: it combines high-frequency signals input to the first port and the second port and outputs them from the fourth port; the load impedance of the two first amplifiers of the peak amplifier varies according to the current level of the high-frequency signal input from the carrier amplifier to the third port.

2. The high-frequency power amplifier according to claim 1, wherein, When the voltage level of the first input signal is increased, the output current of the carrier amplifier saturates at the point in time when the output current of the peak amplifier rises.

3. The high-frequency power amplifier according to claim 1 or 2, wherein, The high-frequency power amplifier further includes a bias control unit for controlling the bias of the carrier amplifier and the peak amplifier. The bias control unit has multiple control modes, and the bias of the carrier amplifier and the peak amplifier is different according to each control mode.

4. The high-frequency power amplifier according to claim 3, wherein, In one of the multiple control modes, the bias control unit causes the two second amplifiers of the carrier amplifier to operate as Dougherty amplifiers.

5. The high-frequency power amplifier according to claim 3 or 4, wherein, In one of the multiple control modes, the bias control unit provides a bias to the two first amplifiers of the peak amplifier that does not generate output current, regardless of the voltage level of the first input signal.

6. The high-frequency power amplifier according to any one of claims 3 to 5, wherein, In one of the multiple control modes, the bias control unit provides a bias to one of the two second amplifiers of the carrier amplifier that does not generate output current regardless of the voltage level of the first input signal, and provides a Class AB or Class B bias to the other second amplifier.

7. The high-frequency power amplifier according to any one of claims 1 to 6, wherein, The two first amplifiers of the peak amplifier and the two second amplifiers of the carrier amplifier are formed on a common substrate. One of the two first amplifiers and one of the two second amplifiers is positioned to be sandwiched between the other.

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