High frequency module and communication device

Abstract

It can suppress the loss of the output signal in the low output mode and also suppress the output signal in the high output mode from entering the signal path used in the low output mode. The high-frequency module (1) includes a first power amplifier (4A), a second power amplifier (4B), a filter (6A), a switch (7), and a matching circuit (5B). The first power amplifier (4A) outputs a first amplified signal. The second power amplifier (4B) outputs a second amplified signal. The filter (6A) allows the first and second amplified signals to pass through. The switch (7) has a first terminal (7b) and a second terminal (7a). The first terminal (7b) is connected to the output of the first power amplifier (4A). The second terminal (7a) is connected to the filter (6A). The switch (7) switches the conduction and cutoff between the first terminal (7b) and the second terminal (7a). The matching circuit (5B) is connected between the output of the second power amplifier (4B) and the signal path between the second terminal (7a) of the switch (7) and the filter (6A).

Description

Technical Field

[0001] The present invention relates to a high-frequency module and a communication device, and more particularly to a high-frequency module having a first power amplifier and a second power amplifier, and a communication device having the high-frequency module. Background Technology

[0002] The transmitting circuit (high-frequency module) described in Patent Document 1 includes a first amplifier, a second amplifier, and two switches. A first path and a second path are connected in parallel between the two switches. The first path is connected to the second amplifier. One switch is connected to an antenna, and the other switch is connected to a signal input unit via the first amplifier.

[0003] In high-output mode, a first path is selected using two switches. The transmitted signal input to the signal input unit is then amplified by the first and second amplifiers before being transmitted from the antenna. In low-output mode, a second path is selected using two switches. The transmitted signal input to the signal input unit is then amplified by the first amplifier and transmitted from the antenna without passing through the second amplifier.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-68283 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In the transmission circuit described in Patent Document 1, the transmission signal is transmitted via two switches in low output mode. Therefore, the transmission signal in low output mode experiences losses in the two switches. Thus, it is necessary to suppress these losses in low output mode. This requires preventing the transmission signal in high output mode from entering the second path (the signal path used in low output mode).

[0009] The purpose of this invention is to provide a high-frequency module and a communication device that can suppress the loss of the output signal in the low output mode and also suppress the output signal in the high output mode from entering the signal path used in the low output mode.

[0010] Solution for solving the problem

[0011] One aspect of the present invention provides a high-frequency module comprising a first power amplifier, a second power amplifier, a filter, a switch, and a matching circuit. The first power amplifier amplifies a first signal to output a first amplified signal. The second power amplifier amplifies the second signal at a smaller amplification rate than the first power amplifier to output a second amplified signal. The filter allows both the first and second amplified signals to pass through. The switch has a first terminal and a second terminal. The first terminal is connected to the output of the first power amplifier. The second terminal is connected to the filter. The switch toggles the conduction and cutoff between the first and second terminals. The matching circuit is connected between the output of the second power amplifier and the signal path between the second terminal of the switch and the filter.

[0012] One aspect of the communication device of the present invention includes the high-frequency module and the signal processing circuit. The signal processing circuit is connected to the high-frequency module and performs signal processing on the high-frequency signal.

[0013] The effects of the invention

[0014] According to the present invention, it has the following advantages: it can suppress the loss of the output signal in the low output mode, and it can also suppress the output signal in the high output mode from entering the signal path used in the low output mode. Attached Figure Description

[0015] Figure 1 This is a block diagram of the high-frequency module and communication device involved in Embodiment 1.

[0016] Figure 2 This is an illustration diagram showing the impedance of a matching circuit.

[0017] Figure 3 This is a circuit structure diagram of the matching circuit of Variation 1 of Implementation Method 1.

[0018] Figure 4 This is a block diagram of the high-frequency module and communication device involved in Embodiment 2. Detailed Implementation

[0019] (Implementation Method 1)

[0020] (1) Summary

[0021] like Figure 1As shown, the high-frequency module 1 according to Embodiment 1 includes a power amplifier 4A (first power amplifier), a power amplifier 4B (second power amplifier), a filter 6A (first filter), a switch 7, and a matching circuit 5B (first matching circuit). The power amplifier 4A amplifies the transmitted signal S1 (first signal) at a first amplification rate to output a first amplified signal. The power amplifier 4B amplifies the transmitted signal S1 (second signal) at a second amplification rate lower than the first amplification rate to output a second amplified signal. The filter 6A allows the first and second amplified signals to pass through. The switch 7 has a terminal 7b (first terminal) and a terminal 7a (second terminal). Terminal 7b is electrically connected to the output of the power amplifier 4A. Terminal 7a is electrically connected to the filter 6A. The switch 7 switches the connection between terminals 7b and 7a. The matching circuit 5B is connected between the path (part of signal path T4) between terminal 7a of the switch 7 and the filter 6A and the output of the power amplifier 4B.

[0022] This structure can suppress the loss of the transmission signal S1 (more specifically, the second amplified signal) in the low output mode (when the signal is cut off between terminals 7a and 7b), and can also suppress the transmission signal S1 (more specifically, the first amplified signal) in the high output mode (when the signal is turned on between terminals 7a and 7b) from entering the signal path (signal path T2 with power amplifier 4B) used in the low output mode.

[0023] (2) Detailed explanation

[0024] Below, refer to Figure 1 The high-frequency module 1 and the communication device 100 involved in Embodiment 1 will be described in detail below.

[0025] (2-1) Structure of the communication device

[0026] like Figure 1 As shown, the communication device 100 is a communication device equipped with a high-frequency module 1. The communication device 100 is, for example, a portable terminal (e.g., a smartphone), but is not limited to this; it could also be, for example, a wearable terminal (e.g., a smartwatch). The high-frequency module 1 is, for example, a module capable of supporting both 4G (fourth-generation mobile communication) and 5G (fifth-generation mobile communication) standards. The 4G standard is, for example, the 3GPP LTE standard (LTE: Long Term Evolution). The 5G standard is, for example, 5G NR (New Radio). The high-frequency module 1 is a module capable of supporting carrier aggregation and dual connectivity.

[0027] In addition to the high-frequency module 1, the communication device 100 also includes a signal processing circuit 2 and one or more (e.g., two) antennas 3 (3A, 3B).

[0028] The high-frequency module 1 is configured to amplify the transmit signal (high-frequency signal) output from the signal processing circuit 2 and transmit it from the antenna 3. More specifically, the high-frequency module 1 has a high-output mode and a low-output mode. The high-output mode is a mode in which the transmit signal is amplified at a first amplification rate and transmitted from the antenna 3. The low-output mode is a mode in which the transmit signal is amplified at a second amplification rate, which is smaller than the first amplification rate, and transmitted from the antenna 3. The high-frequency module 1 is controlled, for example, by the signal processing circuit 2.

[0029] Signal processing circuit 2 is connected to high-frequency module 1 and is configured to process the transmitted signal output to high-frequency module 1. Signal processing circuit 2 includes RF signal processing circuit 21 and baseband signal processing circuit 22. Baseband signal processing circuit 22 is, for example, a BBIC (Baseband Integrated Circuit). Baseband signal processing circuit 22 generates a transmitted signal based on externally input baseband signals (e.g., audio signals and image signals) and outputs the generated transmitted signal to RF signal processing circuit 21. RF signal processing circuit 21 is, for example, an RFIC (Radio Frequency Integrated Circuit) that processes the high-frequency signal (transmitted signal). RF signal processing circuit 21, for example, performs up-conversion and other signal processing on the transmitted signal output from baseband signal processing circuit 22 before outputting it to high-frequency module 1.

[0030] In this embodiment, the high-frequency module 1 uses the antenna 3 to transmit the transmitted signal only and receive the received signal. However, the high-frequency module 1 can also use the antenna 3 to receive the received signal. In this case, the high-frequency module 1 is further configured to amplify the received signal received using the antenna 3 and output it to the signal processing circuit 2. In this case, the signal processing circuit 2 is further configured to perform signal processing on the received signal output from the high-frequency module 1 to the signal processing circuit 2. More specifically, the RF signal processing circuit 21 of the signal processing circuit 2 also performs signal processing such as down-conversion on the received signal output from the high-frequency module 1 and outputs it to the baseband signal processing circuit 22. Then, the baseband signal processing circuit 22 of the signal processing circuit 2 also outputs the received signal received from the RF signal processing circuit 21 to the outside. This output signal (received signal) can be used, for example, as an image signal for image display or as an audio signal for communication.

[0031] (2-2) Circuit structure of high frequency module

[0032] like Figure 1As shown, in the high-frequency module 1, the output sections of multiple (three in the example) power amplifiers 4A to 4C are connected to the transmit filters 6A and 6B using a switch 7. Furthermore, the switch 7 selects the power amplifier used for transmitting the transmit signal S1 from among the multiple power amplifiers 4A to 4C. Thus, the transmit signal S1, amplified by the multiple power amplifiers 4A to 4C, is output to the transmit filters 6A and 6B and transmitted from the antennas 3A and 3B. In the high-frequency module 1, losses in the transmit signal S1 caused by the switch 7 during the low-output mode, where the transmit signal S1 is amplified by power amplifier 4B or 4C, are suppressed. Additionally, the signal paths T2 and T3 (i.e., the signal paths where power amplifiers 4B and 4C are located) used for the transmit signal S1 to enter the low-output mode during the high-output mode, where the transmit signal S1 is amplified by power amplifier 4A, are suppressed.

[0033] The circuit structure of the high-frequency module 1 will be described in detail below. In the following description, the following circuit structure is illustrated: a frequency band selection switch is used as switch 7, and the transmission signal S1 is transmitted through frequency division duplex (FDD).

[0034] like Figure 1 As shown, the high-frequency module 1 transmits high-frequency signals (e.g., transmit signals) between antennas 3A and 3B and signal processing circuit 2.

[0035] The high-frequency module 1 includes multiple (three in the example) power amplifiers 4A to 4C, multiple (three in the example) matching circuits 5A to 5C, multiple (two in the example) transmitting filters 6A and 6B, a switch 7, multiple (three in the example) switches 8A to 8C, a controller 9, and external connection terminals 10 (10A to 10D). Additionally, the high-frequency module 1 includes multiple (five in the example) signal paths T1 to T5.

[0036] Multiple external connection terminals 10 include antenna terminals 10A and 10B, a signal input terminal 10C, and an input terminal 10D. Antenna terminals 10A and 10B are for connecting antennas 3A and 3B, respectively. The signal input terminal 10C is for inputting transmitted signals from the signal processing circuit 2 and is connected to the output of the signal processing circuit 2. The input terminal 10D is for inputting control signals from the signal processing circuit 2 and is connected to the output of the signal processing circuit 2.

[0037] Signal path T1 is the path between signal input terminal 10C and terminals 7b and 7d of switch 7. Switch 8A, power amplifier 4A, and matching circuit 5A are installed on signal path T1. Signal path T4 is the path between terminal 7a of switch 7 and antenna terminal 10A. Transmit filter 6A is installed on signal path T4. Signal path T5 is the path between terminal 7c of switch 7 and antenna terminal 10B. Transmit filter 6B is installed on signal path T5. Signal path T2 is the path between signal input terminal 10C and the following signal path (part of signal path T4): the signal path between terminal 7a of switch 7 and transmit filter 6A. Switch 8B, power amplifier 4B, and matching circuit 5B are installed on signal path T2. Signal path T3 is the path between signal input terminal 10C and the following signal path (part of signal path T5): the signal path between terminal 7c of switch 7 and transmit filter 6B. Switch 8C, power amplifier 4C, and matching circuit 5C are installed on signal path T3.

[0038] In the high-frequency module 1, no switch 7 is provided on the signal path (a portion of signal path T2 and a portion of signal path T4) between the output of power amplifier 4B and the transmitting filter 6A. Furthermore, no switch 7 is provided on the signal path (a portion of signal path T3 and a portion of signal path T5) between the output of power amplifier 4C and the transmitting filter 6B.

[0039] Switches 8A to 8C are respectively located in signal paths T1 to T3, and switch between on and off according to control signals from controller 9, thereby turning signal paths T1 to T3 on and off. Switches 8A to 8C are used to select the signal path used for transmitting signal S1 from among multiple signal paths T1 to T3. Switches 8A to 8C are, for example, integrated circuits (ICs). One end of switches 8A to 8C is connected to signal input terminal 10C, and the other end of switches 8A to 8C is connected to the input section of power amplifiers 4A to 4C.

[0040] Power amplifiers 4A to 4C are respectively disposed in signal paths T1 to T3 to amplify the transmitted signal S1 flowing through signal paths T1 to T3. Power amplifier 4A has a first amplification rate as the amplification rate for amplifying the transmitted signal S1. Power amplifier 4B has a second amplification rate, which is smaller than the first amplification rate, as the amplification rate for amplifying the transmitted signal S1. Power amplifier 4C has a third amplification rate, which is smaller than the first amplification rate, as the amplification rate for amplifying the transmitted signal S1. In this embodiment, the second and third amplification rates are the same, but they can also be different.

[0041] Power amplifiers 4A to 4C have input and output sections. The input sections of power amplifiers 4A to 4C are connected to the terminals of switches 8A to 8C, respectively, and the output sections of power amplifiers 4A to 4C are connected to the input sections of matching circuits 5A to 5C, respectively. Power amplifier 4A amplifies the transmitted signal input to its input section at a first amplification rate and outputs a first amplified signal from its output section. Power amplifier 4B amplifies the transmitted signal input to its input section at a second amplification rate and outputs a second amplified signal from its output section. Power amplifier 4C amplifies the transmitted signal input to its input section at a third amplification rate and outputs a third amplified signal from its output section. Power amplifiers 4A to 4C are controlled by a control signal from controller 9. That is, power amplifiers 4A to 4C switch the power supply on and off according to the control signal from controller 9. This switching switches the bias current of power amplifiers 4A to 4C on and off.

[0042] Matching circuit 5A is used to achieve impedance matching between power amplifier 4A and switch 7. Matching circuit 5A is connected to the signal path (part of signal path T1) between power amplifier 4A and switch 7. Matching circuit 5B is used to achieve impedance matching between power amplifier 4B and transmitting filter 6A. Matching circuit 5B is located in signal path T2, thereby connecting to the signal path between power amplifier 4B and transmitting filter 6A. In other words, matching circuit 5B is connected between the output of power amplifier 4B and the following signal path (part of signal path T4): the signal path between terminal 7a of switch 7 and transmitting filter 6A. Matching circuit 5C is used to achieve impedance matching between power amplifier 4C and transmitting filter 6B. Matching circuit 5C is located in signal path T3, thereby connecting to power amplifier 4C and transmitting filter 6B. In other words, matching circuit 5C is connected between the output of power amplifier 4C and the following signal path (part of signal path T5): the signal path between terminal 7c of switch 7 and transmitting filter 6B.

[0043] Switch 7 is a frequency band selection switch used to select the transmit filter to be used in transmitting the transmit signal S1 from two transmit filters 6A and 6B. Switch 7 is, for example, a switch IC (Integrated Circuit). Switch 7 has two sets of terminals (the first set of terminals 7a and 7b, and the second set of terminals 7c and 7d). The first set of terminals 7a and 7b are mutually connected and disconnected. The second set of terminals 7c and 7d are mutually connected and disconnected. Terminals 7b and 7d are connected to signal path T1, thereby connecting to the output of matching circuit 5A. Terminal 7a is connected to signal path T4, thereby connecting to transmit filter 6A. Terminal 7c is connected to signal path T5, thereby connecting to transmit filter 6B.

[0044] Switch 7 has multiple (two in the example) internal switches 71 and 72. Internal switch 71 switches between selecting and deselecting the transmit filter 6A by turning it on and off. Internal switch 72 switches between selecting and deselecting the transmit filter 6B by turning it on and off. Internal switch 71 is composed of terminals 7a and 7b, and switching between on and off is achieved by turning terminals 7a and 7b on and off. Internal switch 72 is composed of terminals 7c and 7d, and switching between on and off is achieved by turning terminals 7c and 7d on and off.

[0045] Transmit filters 6A and 6B are respectively disposed in signal paths T4 and T5. Transmit filters 6A and 6B are filters that use the transmission bands (communication bands) of different communication frequency bands (e.g., the first communication band and the second communication band) as passbands. Transmit filter 6A allows the amplified signals (first amplified signal and second amplified signal) from power amplifiers 4A and 4B to pass. Transmit filter 6B allows the amplified signals (first amplified signal and third amplified signal) from power amplifiers 4A and 4C to pass. Transmit filters 6A and 6B have input sections and output sections. The input sections of transmit filters 6A and 6B are connected to terminals 7a and 7c of switch 7, respectively. The output sections of transmit filters 6A and 6B are connected to antenna terminals 10A and 10B, respectively. Transmit filters 6A and 6B restrict the received signals input to the input sections to signals within the transmission bands of the first and second communication bands, and output them from the output sections.

[0046] Transmitting filters 6A and 6B are, for example, elastic wave filters. Elastic wave filters are, for example, surface acoustic wave (SAW) filters that utilize surface acoustic waves. Furthermore, transmitting filters 6A and 6B are not limited to SAW filters; in addition to SAW, they can also be, for example, BAW (bulk acoustic wave) filters.

[0047] The controller 9 is a control device that controls electronic components (power amplifiers 4A-4C, matching circuits 5A-5C, transmitting filters 6A and 6B, switch 7, and switches 8A-8C) according to control signals from the signal processing circuit 2. The controller 9 is electrically connected to the aforementioned electronic components. Furthermore, the controller 9 is connected to the output of the signal processing circuit 2 via input terminal 10D. The controller 9 controls each of the aforementioned electronic components according to the control signals input from the signal processing circuit 2 to input terminal 10D.

[0048] (2-3) Operation of communication devices

[0049] Reference Figure 1To explain the operation of the communication device 100.

[0050] The communication device 100 has a high-output mode and a low-output mode. The high-output mode transmits the signal S1 by amplifying it using power amplifier 4A. The low-output mode transmits the signal by amplifying it using power amplifier 4B or 4C. Furthermore, the communication device 100 can select the transmission filter to use during transmission from a plurality of transmission filters 6A and 6B. In the following description, as an example, the operation in the following case is explained: in both the high-output mode and the low-output mode, two transmission filters 6A and 6B are used to transmit the signal S1.

[0051] First, the operation will be explained when transmitting signal S1 using transmit filters 6A and 6B in high output mode. In this case, internal switches 71 and 72 are both turned on. This selects transmit filters 6A and 6B. Additionally, switch 8A is turned on, and switches 8B and 8C are turned off. Furthermore, the power supply to power amplifier 4A is turned on, and the power supplies to power amplifiers 4B and 4C are turned off.

[0052] In this state, when a transmit signal S1 is input from the signal processing circuit 2 to the signal input terminal 10C, the transmit signal S1 flows through signal path T1, internal switch 71, and signal path T4 to be transmitted from antenna 3A. Additionally, the transmit signal S1 flows through signal path T1, internal switch 72, and signal path T5 to be transmitted from antenna 3B. During this time, the transmit signal S1 undergoes processing by power amplifier 4A and matching circuit 5A while flowing through signal path T1. Furthermore, the transmit signal S1 undergoes processing by transmit filters 6A and 6B while flowing through signal paths T4 and T5.

[0053] In high-output mode, the transmission signal S1 is transmitted via switch 7, thus incurring losses due to switch 7. Furthermore, if switch 7 is an existing switch, the losses in the transmission signal S1 in high-output mode caused by switch 7 are not new losses. Therefore, regarding the power of the transmission signal S1 in high-output mode, the previous power is maintained even with the losses caused by switch 7. Consequently, the increase in power caused by the losses due to switch 7 in high-output mode is suppressed.

[0054] In high-output mode, the transmitted signal S1 flowing in signal path T1 (the signal path used in high-output mode) may flow from signal path T1 into signal path T2 (the signal path used in low-output mode), which is electrically connected to terminal 7a of switch 7. However, this inflow is suppressed by the matching circuit 5B provided in signal path T2. More specifically, as described later, the matching circuit 5B is configured such that when viewed from the signal path T1 side used in high-output mode, the impedance of the matching circuit 5B appears to be infinite (also referred to as an open circuit). Therefore, the matching circuit 5B suppresses the flow of the transmitted signal S1 from signal path T1 to signal path T2.

[0055] Furthermore, in high output mode, the power supply to power amplifier 4B is set to off (i.e., the bias current of power amplifier 4B is zero). Therefore, when viewed from the signal path T1 side used in high output mode, the impedance of matching circuit 5B appears even more infinite. As a result, matching circuit 5B further suppresses the flow of transmitted signal S1 from signal path T1 to signal path T2.

[0056] Similarly, in high output mode, the transmitted signal S1 flowing in signal path T1 (the signal path used in high output mode) may flow from signal path T1 into signal path T3 (the signal path used in low output mode), which is electrically connected to terminal 7c of internal switch 72. In this case, the flow is suppressed by the matching circuit 5C provided in signal path T3. More specifically, as described later, the matching circuit 5C is configured such that its impedance appears infinite when viewed from the signal path T1 side (i.e., the internal switch 72 side) used in high output mode. Therefore, the flow of the transmitted signal S1 from signal path T1 to signal path T3 is suppressed by the matching circuit 5C.

[0057] Furthermore, in high output mode, the power supply to power amplifier 4C is set to off (i.e., the bias current of power amplifier 4C is disconnected). Therefore, when viewed from the signal path T1 side used in high output mode, the impedance of matching circuit 5C appears even more infinite. As a result, matching circuit 5C further suppresses the flow of transmitted signal S1 from signal path T1 to signal path T3.

[0058] Next, the operation will be explained when transmitting signal S1 is transmitted using transmit filters 6A and 6B in low output mode. In this case, internal switches 71 and 72 are both set to open. Switches 8B and 8C are both set to close. This selects transmit filters 6A and 6B. Switch 8A is also set to open. Furthermore, the power supplies to power amplifiers 4B and 4C are both closed, while the power supply to power amplifier 4A is closed.

[0059] In this state, when a transmit signal S1 is input from signal processing circuit 2 to signal input terminal 10C, the transmit signal S1 is transmitted from antenna 3A via signal paths T2 and T4, and from antenna 3B via signal paths T3 and T5. During this time, the transmit signal S1 is processed by power amplifier 4B, matching circuit 5B, and transmit filter 6A respectively when flowing through signal paths T2 and T4. Furthermore, the transmit signal S1 is processed by power amplifier 4C, matching circuit 5C, and transmit filter 6B respectively when flowing through signal paths T3 and T5.

[0060] In low output mode, the transmitted signal S1 flowing through signal paths T2 and T4 does not pass through switch 7, thus eliminating the loss caused by passing through switch 7. Therefore, in low output mode, the transmitted signal S1 flowing through signal paths T2 and T4 is transmitted from antenna 3A with the loss caused by switch 7 suppressed.

[0061] Similarly, in low output mode, the transmitted signal S1 flowing through signal paths T3 and T5 does not pass through switch 7, thus avoiding losses due to passing through switch 7. Therefore, in low output mode, the transmitted signal S1 flowing through signal paths T3 and T5 is transmitted from antenna 3B with the losses caused by switch 7 suppressed.

[0062] In low output mode, the transmit signal S1 is amplified by power amplifiers 4B and 4C, therefore the power of the transmit signal S1 is less than that in high output mode. Thus, transmitting the transmit signal S1 in low output mode effectively suppresses losses caused by switch 7, as described above.

[0063] In this way, in the communication device 100, the loss of the transmission signal S1 in the low output mode can be suppressed, and the transmission signal S1 in the high output mode can also be suppressed from entering the signal path T2 and T3 in the low output mode from the signal path T1 used in the high output mode.

[0064] (2-4) Structure of the matching circuit

[0065] In this embodiment, as described above, the matching circuits 5B and 5C are configured such that, when viewed from the high-output signal path T1, the impedance of the matching circuits 5B and 5C appears to be infinite. In other words, the matching circuits 5B and 5C are respectively configured to allow the output signals (second amplified signal and third amplified signal) of the power amplifiers 4B and 4C to pass through, but to prevent the output signal (first amplified signal) of the power amplifier 4A, which enters from the signal path T1 to the signal paths T2 and T3, from passing through.

[0066] Below, refer to Figure 1The matching circuits 5B and 5C will be described in detail below. However, since matching circuits 5B and 5C have the same structure, the following description will focus on the structure of matching circuit 5B. Regarding the structure of matching circuit 5C, the parts that are the same as those in matching circuit 5B will be labeled with the same reference numerals and the description will be omitted.

[0067] Matching circuit 5B is configured to allow the output signal (second amplified signal) of power amplifier 4B to pass through. More specifically, the cutoff frequency of matching circuit 5B is set lower than the frequency of the output signal of power amplifier 4B. In other words, the pass frequency of matching circuit 5B is set to overlap with the frequency of the output signal of power amplifier 4B. Therefore, the output signal of power amplifier 4B can pass through matching circuit 5B. Furthermore, the cutoff frequency of matching circuit 5B refers to the frequency that is blocked from passing through matching circuit 5B. Conversely, the pass frequency of matching circuit 5B refers to the frequency that is allowed to pass through matching circuit 5B.

[0068] Furthermore, the matching circuit 5B is configured such that its impedance appears infinite when viewed from the signal path T1 side used in high output mode. More specifically, the matching circuit 5B includes a high-pass filter 50B. The high-pass filter 50B includes, for example, a capacitor C1 and an inductor L1.

[0069] Capacitor C1 is a series capacitor (hereinafter also referred to as series capacitor C1), connected in series with power amplifier 4B in the signal path between the output of power amplifier 4B and terminal 7a of switch 7. Inductor L1 is a parallel inductor (hereinafter also referred to as parallel inductor L1), connected between signal path T2 and ground. With this structure, a high-pass filter 50B can be constructed with a simple structure. Furthermore, in Figure 1 In the example diagram, capacitor C1 is positioned closer to the power amplifier 4B side than inductor L1. Matching circuit 5B has a high-pass filter 50B, so that the impedance of matching circuit 5B appears infinite when viewed from the signal path T1 on the high output side.

[0070] More specifically, the high-pass filter 50B is the final processing stage (last stage) in the matching circuit 5B, which processes the output signal of the power amplifier 4B input from the input section and outputs it from the output section after processing. In other words, for the transmitted signal entering from the signal path T1 to the signal path T2, the high-pass filter 50B becomes the first processing stage (input stage) in the matching circuit 5A. Therefore, when viewed from the signal path T1 side used in the high output mode, the impedance of the matching circuit 5B appears to be even more infinite due to the impedance of the high-pass filter 50B.

[0071] Matching circuit 5C, like matching circuit 5B, includes a high-pass filter 50C. The high-pass filter 50C includes, for example, a capacitor C3 and an inductor L3. Capacitor C3 is a series capacitor (hereinafter also referred to as series capacitor C3) connected in series with power amplifier 4C in the signal path between the output of power amplifier 4C and terminal 7c of switch 7. Inductor L3 is a parallel inductor (hereinafter also referred to as parallel inductor L3) connected between signal path T3 and ground.

[0072] Next, use Figure 2 The Smith chart shown illustrates why the impedance of matching circuit 5B can appear infinitely large due to the presence of a high-pass filter 50B. The Smith chart is a graph representing the reflection coefficient Γ corresponding to the impedance Z (of matching circuit 5B). The reflection coefficient Γ can be given using the impedance Z and Equation 1. Furthermore, Z0 is the characteristic impedance (reference impedance). Therefore, the impedance Z is a complex number, and thus the reflection coefficient Γ is also a complex number.

[0073] Γ=(Z-Z0) / (Z+Z0) ··· Equation 1

[0074] like Figure 2 As shown, the Smith chart is defined by the equal resistance circle E1 and the equal reactance circle E2. The equal resistance circle E1 is the circle where the real part of the impedance Z takes a fixed value. The equal reactance circle E2 is the arc where the imaginary part of the impedance Z takes a fixed value.

[0075] exist Figure 2 In the Smith chart, as an example, the reflection coefficient Γ is normalized so that it converges within a unit circle of radius 1. Additionally, in... Figure 2 In the diagram, with the center of the aforementioned unit circle as the origin, the vertical axis passing through the origin represents the imaginary part (Im) of the reflection coefficient Γ, and the horizontal axis passing through the origin represents the real part (Re) of the reflection coefficient Γ. Furthermore, in... Figure 2 In the diagram, +1 on the horizontal axis (Γ = Re(+1)) corresponds to the infinity of the impedance Z of the matching circuit 5B, and -1 on the horizontal axis (Γ = Re(-1)) corresponds to the zero impedance Z of the matching circuit 5B (also known as a short circuit).

[0076] In the matching circuit 5B, only Figure 1 When inductor L1 is used as the circuit structure, it is assumed that the reflection coefficient Γ corresponding to the impedance Z of the matching circuit 5B (i.e., the impedance of inductor L1) is located at... Figure 2 Point P1 on the Smith chart. The closer point P1 is to +1 on the horizontal axis of the Smith chart, the more infinite the impedance Z of the matching circuit 5B will appear when viewed from the signal path T1 used in high output mode.

[0077] Therefore, consider the case where point P1 moves towards point P2. Point P2 is a point close to +1 on the horizontal axis of the Smith chart, an example where the impedance Z can appear to be infinite. Figure 2 As shown, for example, point P1 can be moved towards point P2 by moving point P1 counterclockwise along a certain isostatic circle M1(E1). According to the calculation method using the Smith chart, the circuit structure with impedance Z corresponding to point P2 is the circuit structure with impedance Z corresponding to point P1 (i.e., only having...). Figure 1 The structure of inductor L1 includes a capacitor C1 added in series with inductor L1 (i.e., a capacitor C1 added in series in signal path T2). That is, the circuit structure with impedance Z corresponding to point P2 is... Figure 1 The circuit structure shown is that of inductor L1 and capacitor C1 (i.e., the circuit structure of high-pass filter 50B). By having a high-pass filter 50B (i.e., inductor L1 and capacitor C1) in this way, the impedance Z of the matching circuit 5B can appear to be infinite.

[0078] In order to make the impedance Z of the matching circuit 5B appear infinitely when viewed from the signal path T1 side used in high output mode, it is desirable that, Figure 2 In the Smith chart, the real part (Re) of the reflection coefficient Γ corresponding to the impedance Z of the matching circuit 5B is +1. However, it is not limited to the real part (Re) of the reflection coefficient Γ being +1. For example, the real part of the reflection coefficient Γ can be any value greater than 0.7 and less than 1, and it is desirable that it be any value greater than 0.8 and less than 1 (i.e., a value in the range of 0.9 ± 0.1).

[0079] Furthermore, the phase angle corresponding to the reflection coefficient Γ of the impedance Z of the matching circuit 5B, expressed in polar coordinates, is set to θ. To make the impedance Z of the matching circuit 5B appear infinitely large when viewed from the signal path T1 side used in high output mode, in Figure 2 In the Smith chart, the phase angle θ of the reflection coefficient Γ only needs to be in the range of -45 degrees to 45 degrees. This range corresponds to the range where the real part of the reflection coefficient Γ is above 0.7 and below 1.

[0080] (3) Main effects

[0081] The high-frequency module 1 of this embodiment includes a power amplifier 4A (first power amplifier), a power amplifier 4B (second power amplifier), a transmitting filter 6A (first filter), a switch 7, and a matching circuit 5B (first matching circuit). The power amplifier 4A amplifies the transmitting signal S1 (first signal) at a first amplification rate to output a first amplified signal. The power amplifier 4B amplifies the transmitting signal S1 (second signal) at a second amplification rate lower than the first amplification rate to output a second amplified signal. The transmitting filter 6A allows the first and second amplified signals to pass through. The switch 7 has a terminal 7b (first terminal) and a terminal 7a (second terminal). Terminal 7b is electrically connected to the output of the power amplifier 4A. Terminal 7a is electrically connected to the transmitting filter 6A. The switch 7 switches the connection between terminals 7b and 7a. The matching circuit 5B is connected between the path (part of signal path T4) between terminal 7a of the switch 7 and the filter 6A and the output of the power amplifier 4B.

[0082] According to this structure, it is possible to suppress the transmission signal S1 (more specifically, the first amplified signal) in high output mode from entering signal path T2 (the signal path where power amplifier 4B is located) from signal path T1 (the signal path where power amplifier 4A is located), and it is also possible to suppress the loss of transmission signal S1 (more specifically, the second amplified signal) in low output mode. More specifically, the output of power amplifier 4B is electrically connected to terminal 7a of switch 7, so that transmission signal S1 in low output mode can be output to filter 6A without passing through switch 7. Thus, the loss of transmission signal S1 in low output mode caused by switch 7 can be suppressed. In addition, matching circuit 5B is connected between power amplifier 4B and the following signal path (a part of signal path T4): the signal path between terminal 7a of switch 7 and transmission filter 6A. Through this matching circuit 5B, it is possible to suppress transmission signal S1 in high output mode from entering signal path T2 from signal path T1.

[0083] Furthermore, the high-frequency module 1 includes a power amplifier 4C (third power amplifier), a transmitting filter 6B (second transmitting filter), and a matching circuit 5C (third matching circuit). The power amplifier 4C amplifies the transmitting signal S1 (third signal) at a third amplification rate, which is lower than the first amplification rate, to output a third amplified signal. The transmitting filter 6B allows both the first and third amplified signals to pass through. The switch 7 also has a terminal 7c (third terminal) electrically connected to the transmitting filter 6B. The switch 7 switches the connection between terminal 7d (first terminal) and terminal 7c (third terminal). The matching circuit 5C is connected between the output of the power amplifier 4C and the signal path (part of signal path T5) between terminal 7c of the switch 7 and the transmitting filter 6B.

[0084] According to this structure, an additional signal path T3 for the low-output mode can be added, through which the third amplified signal of the power amplifier 4C is output to the transmit filter 6B via the matching circuit 5C. Furthermore, in this case, it is possible to suppress the transmit signal S1 (more specifically, the first amplified signal) in the high-output mode from entering the additional signal path T3 for the low-output mode, and to suppress the loss of the transmit signal S1 (more specifically, the third amplified signal) in the low-output mode. More specifically, the output of the power amplifier 4C is electrically connected to terminal 7c of the switch 7, thus allowing the transmit signal S1 (more specifically, the third amplified signal) in the low-output mode to be output to the transmit filter 6B without passing through the switch 7. Therefore, the loss of the transmit signal S1 (third amplified signal) in the low-output mode caused by the switch 7 can be suppressed. Additionally, through the matching circuit 5C, it is possible to suppress the transmit signal S1 in the high-output mode from entering the signal path T3 from the signal path T1.

[0085] (4) Variations

[0086] A variation of Implementation Method 1 is described.

[0087] In Embodiment 1, an example is shown where the matching circuit 5B includes a series capacitor C1 and a parallel inductor L1 (i.e., a high-pass filter 50B). However, as... Figure 3 As shown, the matching circuit 5B can also have an inductor L2 and a capacitor C2 (i.e., a low-pass filter 51) to replace the series capacitor C1 and the parallel inductor L1.

[0088] Inductor L2 is a series inductor (hereinafter also referred to as series inductor L2), connected in series with power amplifier 4B in the signal path between the output of power amplifier 4B and terminal 7a of switch 7. Capacitor C2 is a parallel capacitor (hereinafter also referred to as parallel capacitor C2), connected between signal path T2 and ground. Furthermore, in Figure 3 In the example diagram, inductor L2 is positioned closer to power amplifier 4B than capacitor C2. Matching circuit 5B is configured such that, by having a low-pass filter 51, its impedance appears infinite when viewed from the signal path T1 on the high output side.

[0089] Matching circuit 5C, like matching circuit 5B, can also have inductor L2 and capacitor C2 to replace series capacitor C1 and parallel inductor L1.

[0090] (Implementation Method 2)

[0091] Reference Figure 4This embodiment will now describe the high-frequency module 1A and the communication device 100. In the high-frequency module 1 of Embodiment 1, a circuit structure is illustrated that uses a frequency band selection switch as switch 7 to transmit signals in frequency division duplex mode. In the high-frequency module 1A of this embodiment, a circuit structure is illustrated that uses a transmit / receive switch as switch 27 to transmit signals in time division duplex (TDD) mode.

[0092] (1) Structure of the communication device

[0093] like Figure 4 As shown, the communication device 100 of this embodiment is the same as the communication device 100 of Embodiment 1, including a high-frequency module 1A, a signal processing circuit 2, and an antenna 3. The signal processing circuit 2 of this embodiment has the same structure as the signal processing circuit 2 of Embodiment 1. Therefore, in the following description, the same reference numerals are used to refer to the same structure as the signal processing circuit 2 of Embodiment 1, and the description is omitted. The description will focus on the structure of the high-frequency module 1A of this embodiment.

[0094] (2) Circuit structure of high frequency module

[0095] like Figure 4 As shown, the high-frequency module 1A transmits high-frequency signals (e.g., transmit signals and receive signals) between the antenna 3 and the signal processing circuit 2.

[0096] The high-frequency module 1A includes multiple (two in the example) power amplifiers 24A and 24B, a low-noise amplifier 25, multiple (two in the example) matching circuits 23A and 23B, a transmit / receive filter 26, a switch 27, multiple (two in the example) switches 31A and 31B, a controller 29, and multiple external connection terminals 30. Additionally, the high-frequency module 1A includes multiple (four in the example) signal paths T6 to T9.

[0097] Multiple external connection terminals 30 include an antenna terminal 30A, a signal input terminal 30B, a signal output terminal 30C, and an input terminal 30D. The antenna terminal 30A is used to connect the antenna 3. The signal input terminal 30B is used to input the transmitted signal S1 from the signal processing circuit 2 and is connected to the output of the signal processing circuit 2. The signal output terminal 30C is used to output the output signal (received signal) of the high-frequency module 1A and is connected to the input of the signal processing circuit 2. The input terminal 30D is used to input the control signal from the signal processing circuit 2 and is connected to the output of the signal processing circuit 2.

[0098] Signal path T6 connects signal input terminal 30B to terminal 27b of switch 27. Switch 31A, power amplifier 24A, and matching circuit 23A are provided on signal path T6. Signal path T9 connects terminals 27a and 27c of switch 27 to antenna terminal 30A. Transmit / receive filter 26 is provided on signal path T9. Signal path T7 connects signal input terminal 30B to the signal path between terminal 27a of switch 27 and transmit / receive filter 26 (part of signal path T9). Switch 31B, power amplifier 24B, and matching circuit 23B are provided on signal path T7. Signal path T8 connects signal output terminal 30C to terminal 27d of switch 27. Low-noise amplifier 25 is provided on signal path T8.

[0099] Switches 31A and 31B are respectively located on signal paths T6 and T7, and switch between on and off according to control signals from controller 29, thereby turning signal paths T6 and T7 on and off. Switches 31A and 31B are used to select the signal path used for transmission or reception from multiple signal paths T6 to T7. Switches 31A and 31B are, for example, integrated circuits (ICs). One end of switches 31A and 31B is connected to signal input terminal 30B, and the other end of switches 31A and 31B is connected to the input sections of power amplifiers 24A and 24B, respectively.

[0100] Power amplifiers 24A and 24B are respectively located in signal paths T6 and T7 to amplify the transmitted signals flowing through signal paths T6 and T7. Power amplifier 24A has a first amplification rate as the amplification rate for amplifying the transmitted signal S1. Power amplifier 24B has a second amplification rate, which is smaller than the first amplification rate, as the amplification rate for amplifying the transmitted signal S1.

[0101] Power amplifiers 24A and 24B have input and output sections. The input sections of power amplifiers 24A and 24B are connected to the terminals of switches 31A and 31B, respectively, and the output sections of power amplifiers 24A and 24B are connected to the input sections of matching circuits 23A and 23B, respectively. Power amplifier 24A amplifies the transmitted signal input to its input section at a first amplification rate and outputs a first amplified signal from its output section. Power amplifier 24B amplifies the transmitted signal input to its input section at a second amplification rate and outputs a second amplified signal from its output section. Power amplifiers 24A and 24B are controlled by a control signal from controller 29. That is, power amplifiers 24A and 24B switch their bias current between on and off according to the control signal from controller 29.

[0102] Matching circuit 23A is a circuit for achieving impedance matching between power amplifier 24A and switch 27, connected in the signal path (part of signal path T6) between power amplifier 24A and switch 27. Matching circuit 23B is a circuit for achieving impedance matching between power amplifier 24B and transmit / receive filter 26, connected between power amplifier 24B and transmit / receive filter 26 by being provided in signal path T7. In other words, matching circuit 23B is connected between the output of power amplifier 24B and the following signal path (part of signal path T9): the signal path between terminal 27a of switch 27 and transmit / receive filter 26. Matching circuit 23A is configured similarly to matching circuit 5A in Embodiment 1. Matching circuit 23B is configured similarly to matching circuit 5B in Embodiment 1. Therefore, matching circuit 23B is configured such that when viewed from the signal path T6 side used in high output mode, the impedance of matching circuit 23B appears to be infinite. In other words, the matching circuit 23B is configured to allow the output signal (second amplified signal) of the power amplifier 24B to pass through, but not to allow the output signal (first amplified signal) of the power amplifier 24A to pass through.

[0103] Switch 27 is a switch (transmit / receive switch) used to select the signal path used for transmission and reception from three signal paths T6 to T8. Switch 27 is, for example, a switch IC. Switch 27 has two sets of terminals (a set of terminals 27a and 27b, and a set of terminals 27c and 27d). The first set of terminals 27a and 27b are mutually connected and disconnected. The second set of terminals 27c and 27d are mutually connected and disconnected. Terminals 27a (the second terminal) and 27c are connected to signal path T9, and thus connected to transmit / receive filter 26. Terminal 27b (the first terminal) is connected to signal path T6, and thus connected to the output of matching circuit 23A. That is, terminal 27b is connected to the output of power amplifier 24A via matching circuit 23A. Terminal 27d is connected to signal path T8, and thus connected to the input of low-noise amplifier 25.

[0104] Switch 27 has multiple (two in the example) internal switches 271 and 272. Internal switch 271 switches between selecting and deselecting signal path T6 by switching between on and off states. Internal switch 272 switches between selecting and deselecting signal path T8 by switching between on and off states. Internal switch 271 is composed of terminals 27a and 27b, and switching between on and off states is achieved by turning terminals 27a and 27b on and off. Internal switch 272 is composed of terminals 27c and 27d, and switching between on and off states is achieved by turning terminals 27c and 27d on and off.

[0105] Transmit / receive filter 26 is disposed in signal path T9. Transmit / receive filter 26 is, for example, a duplexer including a transmit filter and a receive filter. The transmit filter is a filter that uses the transmit band (communication band) of a first frequency band as its passband, and the receive filter is a filter that uses the receive band (communication band) of a second frequency band as its passband. Transmit / receive filter 26 has a first input / output section and a second input / output section. The first input / output section of transmit / receive filter 26 is connected to terminals 27a and 27c of switch 27. The second input / output section of transmit / receive filter 26 is connected to antenna terminal 30A. Transmit / receive filter 26 restricts the transmit signal input to the first input / output section to a signal within the transmit band of the first communication band and outputs it from the second input / output section, and restricts the receive signal input to the second input / output section to a signal within the receive band of the second communication band and outputs it from the first input / output section.

[0106] The transmit / receive filter 26 is, for example, an elastic wave filter. An elastic wave filter is, for example, a surface acoustic wave (SAW) filter that utilizes surface acoustic waves. Furthermore, the transmit / receive filter 26 is not limited to a SAW filter; in addition to SAW, it can also be, for example, a bulk acoustic wave (BAW) filter.

[0107] The controller 29 is a control device that controls electronic components (power amplifiers 24A and 24B, matching circuits 23A and 23B, transmit / receive filter 26, switch 27, and switches 31A and 31B) according to control signals from the signal processing circuit 2. The controller 29 is electrically connected to the aforementioned electronic components. Furthermore, the controller 29 is connected to the output of the signal processing circuit 2 via input terminal 30D. The controller 29 controls each of the aforementioned electronic components according to the control signals from the signal processing circuit 2 input to input terminal 30D.

[0108] (2-1) Operation of communication devices

[0109] Reference Figure 4 This will explain the operation of the communication device 100 when it transmits data.

[0110] The communication device 100 has a high output mode and a low output mode. The high output mode is a mode in which the transmission signal S1 is amplified by the power amplifier 24A. The low output mode is a mode in which the transmission signal S1 is amplified by the power amplifier 24B.

[0111] First, let's explain the operation in high-output mode. In this mode, internal switch 271 is turned on, and internal switch 272 is turned off. Therefore, signal path T6 for high-output mode is selected from the two signal paths T6 and T7 used for transmission. Additionally, switch 31A is turned on, switch 31B is turned off, the power supply to power amplifier 24A is turned on, and the power supply to power amplifier 24B is turned off.

[0112] In this state, when a transmit signal S1 is input from the signal processing circuit 2 to the signal input terminal 30B, the transmit signal S1 flows through the signal path T6, the internal switch 271, and the signal path T9 to be transmitted from the antenna 3. At this time, when the transmit signal S1 flows through the signal path T6, it is processed by the power amplifier 24A and the matching circuit 23A, and when it flows through the signal path T9, it is processed by the transmit / receive filter 26.

[0113] In high-output mode, the transmitted signal S1 flowing in signal path T6 (the signal path used in high-output mode) may flow from signal path T6 into signal path T7 (the signal path used in low-output mode), which is connected to terminal 27a of switch 27. However, this inflow is suppressed by the matching circuit 23B provided in signal path T7. More specifically, the matching circuit 23B is configured such that its impedance appears infinite when viewed from the signal path T6 side used in high-output mode. Therefore, the matching circuit 23B suppresses the flow of the transmitted signal S1 from signal path T6 to signal path T7.

[0114] Furthermore, in high output mode, the power supply to power amplifier 24B is set to off (i.e., the bias current of power amplifier 24B is set to off). Therefore, when viewed from the signal path T6 side used in high output mode, the impedance of matching circuit 23B appears even more infinite. As a result, matching circuit 23B further suppresses the flow of transmitted signal S1 from signal path T6 to signal path T7.

[0115] Next, the operation in low output mode will be explained. In this mode, internal switches 271 and 272 are both set to open. Additionally, switch 31B is set to closed, and switch 31A is set to open. Therefore, signal path T7 is selected from the two signal paths T6 and T7 used for transmission. Furthermore, the power supply to power amplifier 24B is set to open, and the power supply to power amplifier 24A is set to closed.

[0116] In this state, when the transmit signal S1 is input from the signal processing circuit 2 to the signal input terminal 30B, the transmit signal S1 flows through signal paths T7 and T9 to be transmitted from the antenna 3. At this time, when the transmit signal S1 flows through signal path T7, it is processed by the power amplifier 24B and the matching circuit 23B respectively, and when it flows through signal path T9, it is processed by the transmit / receive filter 26.

[0117] In low output mode, the transmitted signal S1 does not pass through switch 27 when flowing through signal paths T7 and T9, thus eliminating the loss caused by passing through switch 27. Therefore, in low output mode, the transmitted signal S1 is transmitted from antenna 3 with the loss caused by switch 27 suppressed.

[0118] The transmit signal S1 in low output mode is amplified by power amplifier 24B, so the power of the transmit signal S1 is less than that in high output mode. Therefore, it is effective to transmit the transmit signal S1 in low output mode while suppressing the losses caused by switch 27, as described above.

[0119] In this way, in the communication device 100, the loss of the transmission signal S1 in the low output mode can be suppressed, and the transmission signal S1 in the high output mode can also be suppressed from entering the signal path T7 in the low output mode from the signal path T6 used in the high output mode.

[0120] (Way)

[0121] The following methods are disclosed in this specification.

[0122] The high-frequency module (1; 1A) involved in the first embodiment includes a first power amplifier (4A; 24A), a second power amplifier (4B; 24B), a filter (6A; 26), a switch (7; 27), and a matching circuit (5B; 23B). The first power amplifier (4A; 24A) amplifies the first signal (S1) to output a first amplified signal. The second power amplifier (4B; 24B) amplifies the second signal (S1) at a smaller amplification rate than the first power amplifier (4A; 24A) to output a second amplified signal. The filter (6A; 26) allows the first and second amplified signals to pass through. The switch (7; 27) has a first terminal (7b; 27b) and a second terminal (7a; 27a). The first terminal (7b; 27b) is connected to the output of the first power amplifier (4A; 24A). The second terminal (7a; 27a) is connected to the filter (6A; 26). Switches (7; 27) toggle the conduction and cutoff between the first terminal (7b; 27b) and the second terminal (7a; 27a). Matching circuits (5B; 23B) are connected between the output of the second power amplifier (4B; 24B) and the signal path between the second terminal (7a; 27a) of switch (7; 27) and the filter (6A; 26).

[0123] According to this structure, it is possible to suppress the transmission signal (S1, first amplified signal) in the high output mode from entering the signal path (T2; T7) used in the low output mode, and it is possible to suppress the loss of the transmission signal (S1, second amplified signal) in the low output mode.

[0124] In the high-frequency module (1; 1A) involved in the second method, in the first method, the matching circuit (5B; 23B) has a high-pass filter (50B). The high-pass filter (50B) is set in the last of one or more processing stages in the matching circuit (5B; 23B) that processes the second amplified signal of the second power amplifier (4B; 24B) and outputs it from the output unit.

[0125] According to this structure, the impedance of the matching circuit (5B; 23B) can appear infinite when viewed from the signal path (T1; T6) used in the high output mode. Thus, the matching circuit (5B; 23B) can further suppress the transmission signal (S1) from the signal path (T1; T6) used in the high output mode to enter the signal path (T2; T7) used in the low output mode.

[0126] In the high-frequency module (1; 1A) involved in the third method, the signal path is set as the first signal path in the second method. In the high-frequency module (1; 1A), the matching circuit (5B; 23B) has a capacitor (C1) and an inductor (L1). The capacitor (C1) is connected in series with the second power amplifier (4B; 24B) on a second signal path different from the first signal path. The second signal path is the signal path between the output of the second power amplifier (4B; 24B) and the second terminal (7a; 27a) of the switch (7; 27). The inductor (L1) is connected between the second signal path and ground.

[0127] According to this structure, it is possible to make the impedance of the matching circuit (5B; 23B) appear infinite when viewed from the signal path (T1) used in high output mode using a simple structure.

[0128] In the high-frequency module (1; 1A) involved in the fourth method, in the second method, the signal path is set as the first signal path. In the high-frequency module (1; 1A), the matching circuit (5B; 23B) has an inductor (L2) and a capacitor (C2). The inductor (L2) is connected in series with the second power amplifier (4B; 24B) on a second signal path different from the first signal path. The second signal path is the signal path between the output of the second power amplifier (4B; 24B) and the second terminal (7a; 27a) of the switch (7; 27). The capacitor (C2) is connected between the second signal path and ground.

[0129] According to this structure, it is possible to make the impedance of the matching circuit (5B; 23B) appear infinite when viewed from the signal path (T1; T6) side used in high output mode using a simple structure.

[0130] In the high-frequency module (1; 1A) involved in the fifth method, under any of the first to fourth methods, the real part (Re) of the reflection coefficient (Γ) corresponding to the impedance (Z) of the matching circuit (5B; 23B) with a value of "+1" and "-1" corresponds to infinity and zero of the impedance (Z), respectively. In this case, the phase angle (θ) when the reflection coefficient (Γ) is expressed in polar coordinates is a value greater than -45 degrees and less than +45 degrees.

[0131] According to this structure, the impedance (Z) of the matching circuit (5B; 23B) can appear to be infinite when viewed from the signal path (T1; T6) side used in the high output mode.

[0132] In the high-frequency module (1; 1A) involved in the sixth method, under any of the first to fifth methods, the real part (Re) of the reflection coefficient (Γ) corresponding to the impedance (Z) of the matching circuit (5B; 23B) with a value of +1 and -1 respectively corresponds to infinity and zero of the impedance (Z). In this case, the real part (Re) of the reflection coefficient (Γ) is a value of 0.7 or higher and less than 1.

[0133] According to this structure, the impedance (Z) of the matching circuit (5B; 23B) can appear to be infinite when viewed from the signal path (T1; T6) side used in the high output mode.

[0134] In the high-frequency module (1; 1A) involved in the seventh method, in any of the first to sixth methods, the bias current of the second power amplifier (4B; 24B) is zero when the switch (7; 27) is in the on state.

[0135] According to this structure, the impedance of the matching circuit (5B; 23B) can be made to appear even more infinite when viewed from the signal path (T1; T6) side used in high output mode.

[0136] In the high-frequency module (1; 1A) involved in the eighth mode, in any of the second to fourth modes, the cutoff frequency of the high-pass filter (50B) is lower than the frequency of the second amplified signal output from the second power amplifier (4B; 24B).

[0137] According to this structure, the second amplified signal of the second power amplifier (4B; 24B) can be effectively passed through the matching circuit (5B; 23B).

[0138] In the high-frequency module (1; 1A) involved in the ninth method, in any of the first to eighth methods, no switch (7; 27) is provided on the signal path between the output of the second power amplifier (4B; 24B) and the filter (6A; 26).

[0139] According to this structure, the transmission signal (S1, second amplified signal) in low output mode can be prevented from being lost due to the switch (7; 27).

[0140] In the high-frequency module (1) involved in the tenth method, in any of the first to ninth methods, the filter (6A) is set as the first filter (6A), and the matching circuit (5B) is set as the first matching circuit (5B). The high-frequency module (1) also includes a third power amplifier (4C), a second filter (6B), and a second matching circuit (5C). The third power amplifier (4C) amplifies the third signal (S1) with a smaller amplification rate than the first power amplifier (4A; 24A) to output a third amplified signal. The second filter (6B) allows the first amplified signal and the third amplified signal to pass through. The switch (7) also has a third terminal (7c) connected to the second filter (6B), and the switch (7) switches the conduction and cutoff between the first terminal (7b) and the third terminal (7c). The second matching circuit (5C) is connected between the output of the third power amplifier (4C) and the signal path between the third terminal (7c) of the switch (7) and the second filter (6B).

[0141] According to this structure, an additional signal path (T3) for the low-output mode can be added, through which the third amplified signal of the third power amplifier (4C) is output to the second filter (6B) via the second matching circuit (5C). Moreover, in this case, it is also possible to suppress the transmission signal (S1, the first amplified signal) in the high-output mode from entering the additional signal path (T3) for the low-output mode, and to suppress the loss of the transmission signal (S1, the third amplified signal) in the low-output mode.

[0142] The communication device (100) involved in the eleventh method includes a high-frequency module (1; 1A) under any one of the first to tenth methods, and a signal processing circuit (2). The signal processing circuit (2) is connected to the high-frequency module (1; 1A) and performs signal processing on the high-frequency signal.

[0143] Based on this structure, a communication device (100) with a high-frequency module (1) having the above-mentioned effects can be provided.

[0144] Explanation of reference numerals in the attached figures

[0145] 1. 1A: High-frequency module; 2: Signal processing circuit; 3. 3A, 3B: Antenna; 4A: Power amplifier (first power amplifier); 4B: Power amplifier (second power amplifier); 4C: Power amplifier (third power amplifier); 5A: Matching circuit; 5B: Matching circuit (first matching circuit); 5C: Matching circuit (second matching circuit); 6A: Transmit filter (filter, first filter); 6B: Transmit filter (second filter); 7: Switch; 7a: Terminal (second terminal); 7b, 7d: Terminal (first terminal); 7c: Terminal (third terminal); 8A-8C: Switch; 9: Controller; 10: External connection terminal; 10A, 10B: Antenna terminal; 10C: Signal input terminal; 10D: Input terminal; 21: RF signal processing circuit; 22: Baseband signal processing circuit; 23A, 23B: Matching circuit; 24A: Power amplifier (first power amplifier) 24B: Power amplifier (second power amplifier); 25: Low noise amplifier; 26: Transmit / receive filter; 27: Switch; 27a, 7a: Terminals (second terminals); 27b, 7b: Terminals (first terminals); 27c: Terminal; 29: Controller; 30: External connection terminal; 30A: Antenna terminal; 30B: Signal input terminal; 30C: Signal output terminal; 30D: Input terminal; 31A, 31B: Switch; 50B, 50C: High-pass filter; 51: Low-pass filter; 71, 72: Internal switches; 100: Communication device; 271, 272: Internal switches; C1, C3: Series capacitors; C2: Parallel capacitors; E1, M1: Equal resistance circles; E2: Equal reactance circles; L1, L3: Parallel inductors; L2: Series inductors; S1: Transmitted signal (first to third signals); T1 to T9: Signal paths; Z: Impedance; Γ: Reflection coefficient; θ: Phase angle.

Claims

1. A high-frequency module, comprising: A first power amplifier amplifies a first signal to output a first amplified signal; The second power amplifier amplifies the second signal at a smaller amplification rate than the first power amplifier to output the second amplified signal. A filter that allows the first amplified signal and the second amplified signal to pass through; A switch having a first terminal connected to the output of the first power amplifier and a second terminal connected to the filter, the switch toggling the connection between the first terminal and the second terminal; and A matching circuit is connected between the output of the second power amplifier and the following signal path: the signal path between the second terminal of the switch and the filter. in, The switch is not provided on the signal path between the output of the second power amplifier and the filter.

2. The high-frequency module according to claim 1, wherein, The matching circuit has a high-pass filter as the last stage of one or more processing stages in the matching circuit that processes the second amplified signal from the second power amplifier and outputs it from the output section.

3. The high-frequency module according to claim 2, wherein, Set the signal path as the first signal path. The matching circuit has: A capacitor is connected in series with the second power amplifier on a second signal path different from the first signal path, the second signal path being the signal path between the output of the second power amplifier and the second terminal of the switch; as well as An inductor is connected between the second signal path and ground.

4. The high-frequency module according to claim 2, wherein, Set the signal path as the first signal path. The matching circuit has: An inductor is connected in series with the second power amplifier on a second signal path different from the first signal path, the second signal path being the signal path between the output of the second power amplifier and the second terminal of the switch; as well as A capacitor is connected between the second signal path and ground.

5. The high-frequency module according to any one of claims 1 to 4, wherein, When the real part of the reflection coefficient corresponding to the impedance of the matching circuit is +1 and -1, respectively, corresponds to infinity and zero of the impedance, When the reflection coefficient is expressed in polar coordinates, the phase angle is a value greater than -45 degrees and less than +45 degrees.

6. The high-frequency module according to any one of claims 1 to 4, wherein, When the real part of the reflection coefficient corresponding to the impedance of the matching circuit is +1 and -1, respectively, corresponds to infinity and zero of the impedance, The real part of the reflection coefficient is a value of 0.7 or higher and 1 or lower.

7. The high-frequency module according to any one of claims 1 to 4, wherein, The bias current of the second power amplifier is zero when the switch is on.

8. The high-frequency module according to any one of claims 2 to 4, wherein, The cutoff frequency of the high-pass filter is lower than the frequency of the second amplified signal output from the second power amplifier.

9. The high-frequency module according to any one of claims 1 to 4, wherein, The filter is designated as the first filter, and the matching circuit is designated as the first matching circuit. The high-frequency module also features: The third power amplifier amplifies the third signal at a smaller amplification rate than the first power amplifier to output the third amplified signal. A second filter allows the first amplified signal and the third amplified signal to pass through; as well as Second matching circuit, The switch also has a third terminal connected to the second filter, and the switch switches between on and off states between the first terminal and the third terminal. The second matching circuit is connected between the output of the third power amplifier and the signal path between the third terminal of the switch and the second filter.

10. The high-frequency module according to claim 1, wherein, There is no switch between the matching circuit and the filter in the signal path.

11. A communication device comprising: The high-frequency module according to any one of claims 1 to 10; and A signal processing circuit, which is connected to the high-frequency module, performs signal processing on the high-frequency signal.

Images