High-frequency circuit

Abstract

Provided is a high-frequency circuit capable of reducing the passing loss of a high-frequency signal in a matching circuit (including a harmonic attenuation circuit) connected to the output end of a power amplifier circuit. A high-frequency circuit (1) is provided with: a power amplifier circuit (10); a harmonic attenuation circuit (30) having an attenuation band including at least a part of the harmonic band of the transmission band of the band A; a matching circuit (20) connected between the harmonic attenuation circuit (30) and the power amplification circuit (10); a filter (51) having a passband including a transmission band of a frequency band A; a switch (41) connected between the harmonic attenuation circuit (30) and the filter (51); a switch (61) connected between the filter (51) and the antenna connection terminal (100); and a switch (63) connected between the matching circuit (20) and the antenna connection terminal (100) without passing through the harmonic attenuation circuit (30).

Description

TECHNICAL FIELD

[0001] The present application relates to a high-frequency circuit. BACKGROUND

[0002] Patent Document 1 discloses a high-frequency module (high-frequency circuit) provided with an output matching circuit connected between an output terminal of a power amplifier and a switch.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENT

[0005] Patent Document 1: International Publication No. 2021 / 117294 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] Generally, a matching circuit connected to an output terminal of a power amplification circuit has a function of harmonic attenuation in addition to a function of impedance conversion. Thus, in a case where the requirement for harmonic attenuation is strict, an increase in the transmission loss of a high-frequency signal in the matching circuit (including a harmonic attenuation circuit) can sometimes become a problem.

[0008] Therefore, the present application provides a high-frequency circuit capable of reducing the transmission loss of a high-frequency signal in a matching circuit (including a harmonic attenuation circuit) connected to an output terminal of a power amplification circuit.

[0009] SOLUTION TO THE PROBLEM

[0010] A high-frequency circuit according to one embodiment of the present application includes a power amplification circuit, a harmonic attenuation circuit having an attenuation frequency band including at least a part of a harmonic frequency band of a transmission frequency band of a first frequency band, a matching circuit connected between the harmonic attenuation circuit and the power amplification circuit, a first filter having a passband including the transmission frequency band of the first frequency band, a first switch connected between the harmonic attenuation circuit and the first filter, a second switch connected between the first filter and an antenna connection terminal, and a third switch connected between the matching circuit and the antenna connection terminal without passing through the harmonic attenuation circuit.

[0011] EFFECT OF THE INVENTION

[0012] According to the present application, it is possible to reduce the transmission loss of a high-frequency signal in a matching circuit (including a harmonic attenuation circuit) connected to an output terminal of a power amplification circuit. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a circuit configuration diagram of a communication device according to Embodiment 1.

[0014] Figure 2FIG. 1 is a diagram showing a first mode of a communication device according to Embodiment 1.

[0015] Figure 3 FIG. 2 is a diagram showing a second mode of the communication device according to Embodiment 1.

[0016] Figure 4 FIG. 3 is a diagram showing a third mode of the communication device according to Embodiment 1.

[0017] Figure 5A FIG. 4 is a circuit configuration diagram of a harmonic attenuation circuit according to Modification 1 of Embodiment 1.

[0018] Figure 5B FIG. 5 is a circuit configuration diagram of a harmonic attenuation circuit according to Modification 2 of Embodiment 1.

[0019] Figure 5C FIG. 6 is a circuit configuration diagram of a harmonic attenuation circuit according to Modification 3 of Embodiment 1.

[0020] Figure 6 FIG. 7 is a circuit configuration diagram of a communication device according to Embodiment 2.

[0021] Figure 7 FIG. 8 is a diagram showing a first mode of the communication device according to Embodiment 2.

[0022] Figure 8 FIG. 9 is a diagram showing a second mode of the communication device according to Embodiment 2.

[0023] Figure 9 FIG. 10 is a diagram showing a third mode of the communication device according to Embodiment 2.

[0024] Figure 10 FIG. 11 is a diagram showing a fourth mode of the communication device according to Embodiment 2. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present application will be described in detail with reference to the drawings. Furthermore, each of the embodiments described below shows a general or specific example. The numerical values, shapes, materials, structural elements, arrangement and connection modes of structural elements, and the like shown in the following embodiments are one example, and the gist of the present application is not intended to be limited to them.

[0026] Furthermore, each of the drawings is a schematic diagram in which emphasis, omission, or adjustment of scale has been appropriately made for the purpose of representing the present application, and is not necessarily strictly illustrated. In some cases, the actual shape, positional relationship, and scale are different from those illustrated. In each of the drawings, the same reference numerals are assigned to substantially the same structures, and repeated description is omitted or simplified in some cases.

[0027] In the following description, "connection" includes not only the case where connection by a connection terminal and / or a wiring conductor is directly made, but also the case where electrical connection is made via other circuit elements. "Connected to between A and B" indicates that connection is made to both A and B between A and B, and indicates that it is arranged in series in a path connecting A and B. "C is connected to between A and B" indicates that one end of C is connected to A and the other end of C is connected to B, and indicates that C is arranged in series in a path connecting between A and B. "A path connecting between A and B" indicates a path constituted by a conductor electrically connecting A and B.

[0028] The "passband of a filter" is a part of a frequency spectrum transmitted through the filter, and is defined as a frequency band between two frequencies at which the power insertion loss is greater than the minimum value by 3 dB.

[0029] The "attenuation band of a harmonic attenuation circuit" is a part of a frequency spectrum attenuated by the harmonic attenuation circuit, and is defined as a frequency band in which the power insertion loss is greater than the minimum value by 5 dB or more.

[0030] The "transmission band" indicates a frequency band used for transmission in a communication device, and the "reception band" indicates a frequency band used for reception in a communication device. For example, in a frequency division duplex (FDD) band, different frequency bands (uplink band and downlink band) are used as the transmission band and the reception band. In addition, for example, in a time division duplex (TDD) band, the same frequency band is used as the transmission band and the reception band.

[0031] The "harmonic band of a prescribed frequency band" indicates a frequency band from n times the low-frequency end of the prescribed frequency band to n times the high-frequency end of the prescribed frequency band. Here, n is a natural number of 2 or more. For example, the second-order harmonic band of a prescribed frequency band is a frequency band from 2 times the low-frequency end of the prescribed frequency band to 2 times the high-frequency end of the prescribed frequency band, and the third-order harmonic band of a prescribed frequency band is a frequency band from 3 times the low-frequency end of the prescribed frequency band to 3 times the high-frequency end of the prescribed frequency band. Furthermore, in the case where no order is added, the "harmonic band" indicates the harmonic bands of all orders.

[0032] The "terminal" indicates a point at which a conductor within a circuit element is terminated. Furthermore, in the case where the impedance of a conductor between circuit elements is sufficiently low, the terminal is interpreted as an arbitrary point on the conductor or the entire conductor between the circuit elements, rather than being interpreted as only a single point.

[0033] The "node" indicates a point of a conductor between circuit elements. Furthermore, in the case where the impedance of a conductor between circuit elements is sufficiently low, the node is interpreted as an arbitrary point on the conductor or the entire conductor between the circuit elements, rather than being interpreted as only a single point.

[0034] A "power class" is a classification of the output power of user equipment (UE) based on its maximum output power. A smaller power class value indicates a higher permissible maximum output power. For example, 3GPP (3rd Generation Partnership Project) specifies power classes 1, 1.5, 2, and 3. Specifically, in power class 1, the maximum output power is specified as 31 dBm. In power class 1.5, the maximum output power is specified as 29 dBm. In power class 2, the maximum output power is specified as 26 dBm. In power class 3, the maximum output power is specified as 23 dBm.

[0035] Furthermore, the maximum output power of the UE is defined as the maximum output power at the antenna end. The maximum output power of the UE is measured using methods defined by 3GPP, etc. For example, the maximum output power can be measured by measuring the radiated power at the antenna. Alternatively, instead of measuring the radiated power, the maximum output power of the antenna can be measured by placing a terminal near the antenna and connecting a measuring instrument (e.g., a spectrum analyzer) to that terminal.

[0036] "Frequency bands supporting specified power levels" refers to frequency bands that can be used at that power level, as defined by standards and specifications. For example, in 3GPP Release 17, the following frequency bands are defined for 5G NR: n1, n3, n34, n39, n40, n41, n77, n78, n79, n95, n97, n98, and n104, which support power level 2. The following frequency bands are defined for 5G NR: n41, n77, n78, and n79, which support power level 1.5.

[0037] (Implementation Method 1)

[0038] The following describes Implementation Method 1.

[0039] [1.1. Circuit Structure of Communication Device]

[0040] First, refer to Figure 1 The circuit structure of the communication device 5 involved in this embodiment will be explained. Figure 1 This is a circuit diagram of the communication device 5 involved in this embodiment.

[0041] also, Figure 1 The circuit structure shown is exemplary; the communication device 5 can be installed using any of a variety of circuit mountings and circuit techniques. Therefore, the description of the communication device 5 provided below should not be interpreted restrictively.

[0042] The communication device 5 can be used to provide wireless connection. For example, the communication device 5 can be installed in a UE in a cellular network (also called a mobile network) of a portable telephone, a smart phone, a tablet computer, a wearable device, and the like. In another example, by installing the communication device 5, wireless connection can be provided to an IoT (Internet of Things) sensor device, a medical / healthcare device, a car, an unmanned aerial vehicle (UAV: Unmanned Aerial Vehicle) (so-called drone), an automated guided vehicle (AGV), and the like. In yet another example, by installing the communication device 5, wireless connection can also be provided using a wireless access point or a wireless hotspot.

[0043] The communication device 5 is provided with the high-frequency circuit 1, the antenna 2, an RFIC (Radio Frequency Integrated Circuit) 3, and a BBIC (Baseband Integrated Circuit) 4.

[0044] The high-frequency circuit 1 is connected between the antenna 2 and the RFIC 3. The high-frequency circuit 1 can transmit a high-frequency signal between the antenna 2 and the RFIC 3. Details of the circuit structure of the high-frequency circuit 1 are described later.

[0045] The antenna 2 is connected to the high-frequency circuit 1. The antenna 2 can receive a high-frequency signal from the high-frequency circuit 1 and transmit the high-frequency signal to the outside of the communication device 5. Also, the antenna 2 can receive a high-frequency signal from the outside of the communication device 5 and supply the high-frequency signal to the high-frequency circuit 1. In addition, the antenna 2 can not be included in the communication device 5. Further, the communication device 5 can be provided with one or more antennas in addition to the antenna 2.

[0046] The RFIC 3 is an example of a signal processing circuit that processes a high-frequency signal. Specifically, the RFIC 3 can perform signal processing such as frequency up-conversion on a transmission signal input from the BBIC 4 and output a high-frequency transmission signal generated by the signal processing to the high-frequency circuit 1. Also, the RFIC 3 can perform signal processing such as frequency down-conversion on a high-frequency reception signal input via a reception path of the high-frequency circuit 1 and output a reception signal generated by the signal processing to the BBIC 4. Further, the RFIC 3 can have a control section that controls a switch circuit and a power amplification circuit and the like possessed by the high-frequency circuit 1. In addition, a part or all of the functions of the control section of the RFIC 3 can be included outside the RFIC 3, for example, in the BBIC 4 or the high-frequency circuit 1.

[0047] The BBIC 4 is a baseband signal processing circuit that performs signal processing using a frequency band lower than the high-frequency signal transmitted by the high-frequency circuit 1. As a signal processed by the BBIC 4, for example, an image signal is used to display an image and / or a sound signal is used to make a call by means of a speaker. Furthermore, a part or all of the BBIC 4 can also not be included in the communication device 5.

[0048] [1.2. Circuit structure of high-frequency circuit 1]

[0049] Next, the circuit structure of the high-frequency circuit 1 according to the present embodiment will be described with reference to Figure 1 Furthermore, Figure 1 An exemplary circuit structure is shown, and the high-frequency circuit 1 can be installed using any of a variety of circuit mounting and circuit technologies. Thus, the description of the high-frequency circuit 1 provided below should not be interpreted restrictively.

[0050] The high-frequency circuit 1 includes a power amplification circuit 10, a matching circuit 20, a harmonic attenuation circuit 30, switch circuits 40 and 60, filters 51 and 52, an antenna connection terminal 100, and a high-frequency input terminal 110.

[0051] The antenna connection terminal 100 is an external connection terminal of the high-frequency circuit 1, and is a terminal for supplying a high-frequency signal to the antenna 2. The antenna connection terminal 100 is connected to the antenna 2 outside the high-frequency circuit 1, and is connected to the switch circuit 60 inside the high-frequency circuit 1.

[0052] The high-frequency input terminal 110 is an external connection terminal of the high-frequency circuit 1, and is a terminal for receiving a high-frequency signal from the RFIC 3. The high-frequency input terminal 110 is connected to the RFIC 3 outside the high-frequency circuit 1, and is connected to the power amplification circuit 10 inside the high-frequency circuit 1.

[0053] [1.2.1. Power amplification circuit 10]

[0054] The power amplification circuit 10 is connected between the high-frequency input terminal 110 and the matching circuit 20. Specifically, the input terminal of the power amplification circuit 10 is connected to the high-frequency input terminal 110, and the output terminal of the power amplification circuit 10 is connected to the matching circuit 20. The power amplification circuit 10 can amplify a high-frequency signal using power supplied from a power source (not shown).

[0055] In the present embodiment, the power amplification circuit 10 is an amplification circuit that includes two power amplifiers connected in parallel, for example, a differential amplification type, a balanced type, or a Doherty type amplification circuit. The power amplification circuit 10 includes power amplifiers 11 and 12, a combiner 13, and a divider 14.

[0056] The power amplifier 11 is an example of a first power amplifier, and is connected between the distributor 14 and the combiner 13. Specifically, the input terminal of the power amplifier 11 is connected to the output terminal 142 of the distributor 14, and the output terminal of the power amplifier 11 is connected to the input terminal 131 of the combiner 13.

[0057] The power amplifier 12 is an example of a second power amplifier, and is connected between the distributor 14 and the combiner 13. Specifically, the input terminal of the power amplifier 12 is connected to the output terminal 143 of the distributor 14, and the output terminal of the power amplifier 12 is connected to the input terminal 132 of the combiner 13.

[0058] The combiner 13 is connected between the power amplifiers 11 and 12 and the matching circuit 20. Specifically, the combiner 13 includes the input terminals 131 and 132, and the output terminal 133. The input terminal 131 is an example of a first input terminal, and is connected to the output terminal of the power amplifier 11. The input terminal 132 is an example of a second input terminal, and is connected to the output terminal of the power amplifier 12. The output terminal 133 is connected to the matching circuit 20. As the combiner 13, for example, a transformer, a 90-degree hybrid coupler, a 180-degree hybrid coupler, a Wilkinson coupler, or the like can be used, and there is no particular limitation.

[0059] The distributor 14 is connected between the high-frequency input terminal 110 and the power amplifiers 11 and 12. Specifically, the distributor 14 includes the input terminal 141 connected to the high-frequency input terminal 110, the output terminal 142 connected to the input terminal of the power amplifier 11, and the output terminal 143 connected to the input terminal of the power amplifier 12. As the distributor 14, for example, a transformer, a 90-degree hybrid coupler, a 180-degree hybrid coupler, a Wilkinson coupler, or the like can be used, and there is no particular limitation. Furthermore, the distributor 14 can not be included in the power amplification circuit 10, and can not be included in the high-frequency circuit 1.

[0060] Part or all of the power amplification circuit 10 can be mounted on a semiconductor integrated circuit. As a semiconductor material of the semiconductor integrated circuit, for example, silicon germanium (SiGe) or gallium arsenide (GaAs) can be used. At this time, part or all of the power amplifiers 11 and 12 can be constituted by a heterojunction bipolar transistor (HBT). In addition, as a semiconductor material of the power amplification circuit 10, gallium nitride (GaN) or silicon carbide (SiC) can also be used. At this time, part or all of the power amplifiers 11 and 12 can be constituted by a HEMT (High Electron Mobility Transistor) or a MESFET (Metal-Semiconductor Field Effect Transistor). In addition, as a semiconductor material of the power amplification circuit 10, single crystal silicon (Si) can also be used. At this time, part or all of the power amplifiers 11 and 12 can also be constituted by a CMOS (Complementary Metal Oxide Semiconductor), and can also be manufactured by an SOI (Silicon on Insulator) process. The power amplification circuit 10 can also be mounted in a plurality of semiconductor integrated circuits.

[0061] Further, the power amplification circuit 10 can also be a multi-stage amplification circuit. In this case, the power amplification circuit 10 can also include a power amplifier connected between the high-frequency input terminal 110 and the distributor 14. In addition, the power amplification circuit 10 can also not include two power amplifiers connected in parallel. In this case, the power amplification circuit 10 can also not include the power amplifier 12, the combiner 13, and the distributor 14.

[0062] [1.2.2. Matching circuit 20]

[0063] The matching circuit 20 is connected between the power amplification circuit 10 and the antenna connection terminal 100. Specifically, an input terminal of the matching circuit 20 is connected to the power amplification circuit 10, and an output terminal of the matching circuit 20 is connected to the harmonic attenuation circuit 30 and the switching circuit 60. The matching circuit 20 can achieve impedance matching between the power amplification circuit 10 and the harmonic attenuation circuit 30 and the switching circuit 60. In the present embodiment, the matching circuit 20 includes a capacitor 21 and an LC series circuit 22.

[0064] The capacitor 21 is a so-called DC (Direct Current) cut capacitor and a coupling capacitor, and is connected between the power amplification circuit 10 and the harmonic attenuation circuit 30. Specifically, one of the two electrodes of the capacitor 21 is connected to the output terminal of the power amplification circuit 10, and the other of the two electrodes of the capacitor 21 is connected to the input terminal of the harmonic attenuation circuit 30.

[0065] The LC series circuit 22 is connected between the path connecting the capacitor 21 and the harmonic attenuation circuit 30 and the ground. The LC series circuit 22 includes a capacitor 221 and an inductor 222 connected in series.

[0066] Further, the circuit structure of the matching circuit 20 is not limited to the circuit structure of Figure 1 For example, the LC series circuit 22 can also be connected between the path connecting the capacitor 21 and the harmonic attenuation circuit 30 and the ground.

[0067] [1.2.3. Harmonic attenuation circuit 30]

[0068] The harmonic attenuation circuit 30 has an attenuation frequency band including at least a part of the harmonic frequency band of the transmission frequency band including the frequency bands A and C. The harmonic attenuation circuit 30 is connected between the matching circuit 20 and the switching circuit 40. Specifically, the input terminal of the harmonic attenuation circuit 30 is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuation circuit 30 is connected to the common terminal 400 of the switching circuit 40. The harmonic attenuation circuit 30 can attenuate the harmonics of the signals of the frequency bands A and C.

[0069] In the present embodiment, the harmonic attenuation circuit 30 includes an LC parallel circuit 31 connected between the matching circuit 20 and the switching circuit 40. Further, the harmonic attenuation circuit 30 does not include a ground connection. That is, the harmonic attenuation circuit 30 does not include an active element and a passive element connected between the path connecting the matching circuit 20 and the switching circuit 40 and the ground.

[0070] The LC parallel circuit 31 includes an inductor 311 and a capacitor 312 connected in parallel between the matching circuit 20 and the switching circuit 40. The capacitor 312 is a variable capacitor capable of changing the electrostatic capacity.

[0071] Further, the circuit structure of the harmonic attenuation circuit 30 is not limited to the circuit structure of Figure 1 For example, the capacitor 312 can also not be a variable capacitor, but can be a fixed capacitor.

[0072] [1.2.4. Switching circuit 40]

[0073] The switch circuit 40 is connected between the harmonic attenuating circuit 30 and the filters 51 and 52. Specifically, the switch circuit 40 includes a common terminal 400, selection terminals 401 and 402, and switches 41 and 42. The common terminal 400 is connected to the output terminal of the harmonic attenuating circuit 30. The selection terminal 401 is connected to the filter 51. The selection terminal 402 is connected to the filter 52. Further, in the case where the filter 52 is not included in the high-frequency circuit 1, the selection terminal 402 can also not be included in the switch circuit 40.

[0074] The switch 41 is an example of a first switch and is connected between the common terminal 400 and the selection terminal 401. That is, the switch 41 is connected between the harmonic attenuating circuit 30 and the filter 51.

[0075] The switch 42 is an example of a fourth switch and is connected between the common terminal 400 and the selection terminal 402. That is, the switch 42 is connected between the harmonic attenuating circuit 30 and the filter 52. Further, in the case where the filter 52 is not included in the high-frequency circuit 1, the switch 42 can also not be included in the switch circuit 40.

[0076] In this connection structure, the switch circuit 40 controls the switches 41 and 42, for example, on the basis of a control signal from the RFIC 3, whereby the common terminal 400 can be selectively connected to the selection terminals 401 and 402. That is, the switch circuit 40 can switch the connection of the harmonic attenuating circuit 30 between the filters 51 and 52. This switch circuit 40 is constituted by, for example, a switch circuit of the SPDT (Single-Pole Double-Throw) type.

[0077] The switch circuit 40 can be mounted on a semiconductor integrated circuit. As a semiconductor material of the semiconductor integrated circuit, for example, single-crystal silicon (Si), gallium nitride (GaN), or silicon carbide (SiC) can be used. At this time, a part or all of the switches 41 and 42 can be constituted by a field effect transistor (FET). Further, a bipolar transistor can also be used instead of the FET. In addition, the switch circuit 40 can also be mounted in a plurality of semiconductor integrated circuits.

[0078] Further, the circuit structure of the switch circuit 40 is not limited to Figure 1 The switch circuit 40 can also include one or more additional common terminals and / or one or more additional selection terminals. In this case, the switch circuit 40 can also include one or more additional switches. For example, the switch circuit 40 can also include a switch connected between the matching circuit 20 and the switch circuit 60 without passing through the harmonic attenuating circuit 30.

[0079] [1.2.5. Filters 51 and 52]

[0080] Filter 51 is an example of a first filter, and is a bandpass filter having a passband including a transmission frequency band of frequency band A. Filter 51 is connected between switch circuits 40 and 60. Specifically, one end of filter 51 is connected to selection terminal 401 of switch circuit 40, and the other end of filter 51 is connected to selection terminal 601 of switch circuit 60.

[0081] Filter 52 is an example of a second filter, and is a bandpass filter having a passband including a transmission frequency band of frequency band C. Filter 52 is connected between switch circuits 40 and 60. Specifically, one end of filter 52 is connected to selection terminal 402 of switch circuit 40, and the other end of filter 52 is connected to selection terminal 602 of switch circuit 60. In addition, filter 52 can not be included in high-frequency circuit 1.

[0082] As filters 51 and 52, a surface acoustic wave (SAW) filter, a bulk acoustic wave (BAW) filter, an LC filter, or a dielectric filter, or any combination thereof can be used, and are not limited thereto.

[0083] In addition, filters 51 and 52 are not limited to bandpass filters. Part or all of filters 51 and 52 can be band elimination filters, or can be highpass filters or lowpass filters.

[0084] In addition, high-frequency circuit 1 can further include an additional filter. For example, high-frequency circuit 1 can include an additional filter connected between matching circuit 20 and switch 63.

[0085] [1.2.6. Switch circuit 60]

[0086] Switch circuit 60 is connected between filters 51 and 52 and matching circuit 20 and antenna connection terminal 100. Specifically, switch circuit 60 includes common terminal 600, selection terminals 601, 602, and 603, and switches 61, 62, and 63. Common terminal 600 is connected to antenna connection terminal 100. Selection terminal 601 is connected to filter 51. Selection terminal 602 is connected to filter 52. In addition, in the case where filter 52 is not included in high-frequency circuit 1, selection terminal 602 can not be included in switch circuit 60. Selection terminal 603 is connected to matching circuit 20 without passing through harmonic attenuation circuit 30. Specifically, selection terminal 603 is connected to node N23 on a path connecting matching circuit 20 and harmonic attenuation circuit 30.

[0087] The switch 61 is an example of a second switch and is connected between the common terminal 600 and a selection terminal 601. That is, the switch 61 is connected between the antenna connection terminal 100 and the filter 51.

[0088] The switch 62 is an example of a fifth switch and is connected between the common terminal 600 and a selection terminal 602. That is, the switch 62 is connected between the antenna connection terminal 100 and the filter 52. Further, in a case where the filter 52 is not included in the high-frequency circuit 1, the switch 62 can also not be included in the switch circuit 60.

[0089] The switch 63 is an example of a third switch and is connected between the common terminal 600 and a selection terminal 603. That is, the switch 63 is connected between the antenna connection terminal 100 and the matching circuit 20 without passing through the harmonic attenuating circuit 30. Further, the switch 63 can also not be included in the switch circuit 60. For example, the switch 63 can also be included in the switch circuit 40.

[0090] In this connection structure, the switch circuit 60 controls the switches 61 to 63, for example, based on a control signal from the RFIC 3, whereby the common terminal 600 can be selectively connected to the selection terminals 601 to 603. That is, the switch circuit 60 can switch the connection of the antenna connection terminal 100 between the filters 51 and 52 and the matching circuit 20. This switch circuit 60 is constituted by, for example, an SP3T (Single-Pole Triple-Throw) type switch circuit.

[0091] The switch circuit 60 can be mounted on a semiconductor integrated circuit. As a semiconductor material of the semiconductor integrated circuit, for example, a single-crystal silicon (Si), gallium nitride (GaN), or silicon carbide (SiC) can be used. At this time, a part or all of the switches 61 to 63 can be constituted by FETs. Further, a bipolar transistor can also be used instead of the FETs. In addition, the switch circuit 60 can be mounted as divided into a plurality of semiconductor integrated circuits or can be included in the same semiconductor integrated circuit as the switch circuit 40.

[0092] Further, the circuit structure of the switch circuit 60 is not limited to the circuit structure of Figure 1 The switch circuit 60 can also include one or more additional common terminals and / or one or more additional selection terminals. In this case, the switch circuit 60 can also include one or more additional switches.

[0093] [1.3. Frequency bands]

[0094] Here, the frequency bands A, B, and C supported by the communication device 5 are described.

[0095] Frequency bands A through C are frequency bands used in communication systems built using Radio Access Technology (RAT). Frequency bands A through C are predefined by standardization organizations such as 3GPP and IEEE (Institute of Electrical and Electronics Engineers). Examples of communication systems include 5G NR (5th Generation New Radio), 4G LTE (4th Generation Long Term Evolution), and 2G GSM (2nd Generation Global System for Mobile communications).

[0096] In this embodiment, frequency bands A and C are examples of the first and third frequency bands, respectively, and are 5G NR frequency bands. Alternatively, frequency bands A and / or C can also be 4G LTE frequency bands.

[0097] In this embodiment, frequency band B is an example of a second frequency band, specifically a 2G GSM band. Alternatively, frequency band B could also be a 5G NR band or a 4G LTE band. In this case, the maximum output power of the transmitted signal in frequency band B can be lower than the maximum output power of the transmitted signals in frequency bands A and C. That is, frequency band B can also be a band operating in low-power mode (LPM).

[0098] [1.4. Multiple Communication Modes of Communication Device 5]

[0099] Next, the multiple communication modes of communication device 5 will be explained.

[0100] [1.4.1. First Mode]

[0101] First, refer to Figure 2 This will be used to explain the first mode among multiple communication modes. The first mode is a communication mode used to transmit high-frequency signals (an example of a first high-frequency signal) in the transmission band of frequency band A.

[0102] In the first mode, switch circuit 40 connects common terminal 400 to select terminal 401 but not to select terminal 402. That is, switch 41 is closed and switch 42 is open. Furthermore, switch circuit 60 connects common terminal 600 to select terminal 601 but not to select terminals 602 and 603. That is, switch 61 is closed and switches 62 and 63 are open.

[0103] Thus, the transmission signal of the frequency band A is transmitted from the RFIC 3 to the antenna 2 via the high-frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the harmonic attenuation circuit 30, the switch circuit 40, the filter 51, the switch circuit 60, and the antenna connection terminal 100.

[0104] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to be the first electrostatic capacitance. Thus, the resonance frequency of the LC parallel circuit 31 is included in the harmonic frequency band of the transmission frequency band of the frequency band A. As a result, the harmonic attenuation circuit 30 can effectively attenuate the signal of the harmonic frequency band of the transmission frequency band of the frequency band A.

[0105] [1.4.2. Second Mode]

[0106] Next, the second mode included in the plurality of communication modes will be described with reference to Figure 3 The second mode is a communication mode for transmitting a high-frequency signal of the transmission frequency band of the frequency band B (an example of the second high-frequency signal).

[0107] In the second mode, the switch circuit 40 does not connect the common terminal 400 with the selection terminals 401 and 402. That is, the switches 41 and 42 are open. Also, the switch circuit 60 connects the common terminal 600 with the selection terminal 603 and does not connect the common terminal 600 with the selection terminals 601 and 602. That is, the switch 63 is closed, and the switches 61 and 62 are open.

[0108] Thus, the transmission signal of the frequency band B is transmitted from the RFIC 3 to the antenna 2 via the high-frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the switch circuit 60, and the antenna connection terminal 100. That is, the transmission signal of the frequency band B is transmitted to the antenna 2 without passing through the harmonic attenuation circuit 30.

[0109] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to be the second electrostatic capacitance which is larger than the first electrostatic capacitance. Thus, the resonance frequency of the LC parallel circuit 31 is included in the transmission frequency band of the frequency band B. As a result, the impedance of the harmonic attenuation circuit 30 in the transmission frequency band of the frequency band B increases, and it is possible to reduce the voltage applied to the common terminal 400 of the switch circuit 40.

[0110] [1.4.3. Third Mode]

[0111] Next, the third mode included in the plurality of communication modes will be described with reference to Figure 4 The third mode is a communication mode for transmitting a high-frequency signal of the transmission frequency band of the frequency band C (an example of the third high-frequency signal).

[0112] In the third mode, the switch circuit 40 connects the common terminal 400 with the selection terminal 402 and does not connect the common terminal 400 with the selection terminal 401. That is, the switch 42 is closed and the switch 41 is opened. Also, the switch circuit 60 connects the common terminal 600 with the selection terminal 602 and does not connect the common terminal 600 with the selection terminals 601 and 603. That is, the switch 62 is closed and the switches 61 and 63 are opened.

[0113] Thus, the transmission signal of the frequency band C is transmitted from the RFIC 3 to the antenna 2 via the high-frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the harmonic attenuation circuit 30, the switch circuit 40, the filter 52, the switch circuit 60, and the antenna connection terminal 100.

[0114] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to the third static capacitance. Thus, the resonance frequency of the LC parallel circuit 31 is included in the harmonic frequency band of the transmission frequency band of the frequency band C. As a result, the harmonic attenuation circuit 30 can effectively attenuate the signal of the harmonic frequency band of the transmission frequency band of the frequency band C.

[0115] [1.5. SUMMARY]

[0116] As described above, the high-frequency circuit 1 according to the present embodiment includes the power amplification circuit 10, the harmonic attenuation circuit 30 having an attenuation frequency band including at least a part of a harmonic frequency band of a transmission frequency band of a frequency band A, the matching circuit 20 connected between the harmonic attenuation circuit 30 and the power amplification circuit 10, the filter 51 having a passband including the transmission frequency band of the frequency band A, the switch 41 connected between the harmonic attenuation circuit 30 and the filter 51, the switch 61 connected between the filter 51 and the antenna connection terminal 100, and the switch 63 connected between the matching circuit 20 and the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30.

[0117] Accordingly, the matching circuit connected to the output terminal of the power amplification circuit 10 is divided into the matching circuit 20 and the harmonic attenuation circuit 30, and a transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30 is realized. Also, the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 with passing through the harmonic attenuation circuit 30 and the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30 can be switched by the switches 41, 61, and 63. Thus, in transmission of a high frequency signal for which the attenuation of harmonics is strictly required, the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 with passing through the harmonic attenuation circuit 30 is used, and thus the attenuation of harmonics can be satisfied. On the other hand, in transmission of a high frequency signal for which the attenuation of harmonics is not strictly required, the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30 is used, and thus the passage loss of the high frequency signal in the harmonic attenuation circuit 30 can be reduced. That is, the high frequency circuit 1 can reduce the passage loss of the high frequency signal in the harmonic attenuation circuit 30 while satisfying the attenuation of harmonics.

[0118] Also, for example, in the high frequency circuit 1 according to the present embodiment, the harmonic attenuation circuit 30 can include the inductor 311 connected between the matching circuit 20 and the switch 41, and can not include the ground connection.

[0119] Accordingly, the harmonic attenuation circuit 30 does not include the ground connection, and thus when the switch 41 is opened and the switch 63 is closed, the influence of the harmonic attenuation circuit 30 on the signal path of the frequency band B can be suppressed even if the harmonic attenuation circuit 30 does not include the switch. Also, the inductor 311 is connected between the matching circuit 20 and the switch 41, and thus the passage loss of the inductor 311 is large, and the effect of reducing the passage loss of the high frequency signal in the harmonic attenuation circuit 30 is large.

[0120] Also, for example, in the high frequency circuit 1 according to the present embodiment, in a first mode for transmitting a first high frequency signal of a transmission frequency band of the frequency band A, the switches 41 and 61 can be closed and the switch 63 can be opened, and in a second mode for transmitting a second high frequency signal of a transmission frequency band of the frequency band B, the switch 63 can be closed and the switches 41 and 61 can be opened.

[0121] Accordingly, the first mode is used in a case where the attenuation of harmonics is strictly required, whereby the first high-frequency signal can be transmitted via the harmonic attenuation circuit 30. On the other hand, the second mode is used in a case where the attenuation of harmonics is not strictly required, whereby the second high-frequency signal can be transmitted without passing through the harmonic attenuation circuit 30. Thus, for transmission of the first high-frequency signal for which the attenuation of harmonics is strictly required, the attenuation requirement of harmonics can be satisfied, and in transmission of the second high-frequency signal for which the attenuation of harmonics is not strictly required, the through loss of the second high-frequency signal in the harmonic attenuation circuit 30 can be reduced.

[0122] Further, for example, in the high-frequency circuit 1 according to the present embodiment, the frequency band A can also be a 5G NR frequency band or a 4G LTE frequency band, and the frequency band B can also be a 2G GSM frequency band.

[0123] Accordingly, the first mode can be used in transmission of the first high-frequency signal of the 5G NR frequency band or the 4G LTE frequency band for which the attenuation of harmonics is strictly required, and the second mode can be used in transmission of the second high-frequency signal of the 2G GSM frequency band for which the attenuation of harmonics is not strictly required.

[0124] Further, for example, in the high-frequency circuit 1 according to the present embodiment, the frequency bands A and B can also be 5G NR frequency bands or 4G LTE frequency bands, and the maximum output power of the first high-frequency signal can be higher than that of the second high-frequency signal.

[0125] Accordingly, in a low power mode (LPM) in which a lower maximum output power is applied, the attenuation of harmonics is not strictly required, and thus signal loss can be reduced by using the second mode.

[0126] Further, for example, the high-frequency circuit 1 according to the present embodiment can further include a filter 52 having a passband including a transmission frequency band of a frequency band C, a switch 42 connected between the harmonic attenuation circuit 30 and the filter 52, and a switch 62 connected between the filter 52 and the antenna connection terminal 100.

[0127] Accordingly, the high-frequency signal of the frequency band C can be transmitted via the harmonic attenuation circuit 30, the attenuation requirement of harmonics can be satisfied in transmission of the signal of the frequency band C in addition to the frequency band A, and the through loss of the signal of the frequency band B in the harmonic attenuation circuit 30 can be reduced in transmission of the signal of the frequency band B.

[0128] Further, for example, in the high-frequency circuit 1 according to the present embodiment, in a third mode for transmitting a third high-frequency signal of a transmission frequency band of the frequency band C, the switches 42 and 62 can also be closed, and the switches 41, 61, and 63 can also be opened.

[0129] Accordingly, the third mode is used in a case where the attenuation of harmonics is strictly required, whereby the third high frequency signal can be transmitted via the harmonic attenuation circuit 30.

[0130] Further, for example, in the high frequency circuit 1 according to the present embodiment, the harmonic attenuation circuit 30 can include an LC parallel circuit 31 connected between the matching circuit 20 and the switch 41.

[0131] Accordingly, the LC parallel circuit 31 can be used to attenuate harmonics.

[0132] Further, for example, in the high frequency circuit 1 according to the present embodiment, the capacitor 312 of the LC parallel circuit 31 can be a variable capacitor.

[0133] Accordingly, the electrostatic capacitance of the capacitor 312 of the LC parallel circuit 31 can be changed.

[0134] Further, for example, in the high frequency circuit 1 according to the present embodiment, in the first mode for transmitting the first high frequency signal of the transmission frequency band of the frequency band A, the capacitor 312 can be controlled to a first electrostatic capacitance, and in the second mode for transmitting the second high frequency signal of the transmission frequency band of the frequency band B, the capacitor 312 can be controlled to a second electrostatic capacitance larger than the first electrostatic capacitance.

[0135] Accordingly, the attenuation frequency band of the harmonic attenuation circuit 30 can be changed by changing the electrostatic capacitance of the capacitor 312.

[0136] Further, for example, in the high frequency circuit 1 according to the present embodiment, in the first mode for transmitting the first high frequency signal of the transmission frequency band of the frequency band A, the capacitor 312 can be controlled to a first electrostatic capacitance such that the resonance frequency of the LC parallel circuit 31 is included in the harmonic frequency band of the transmission frequency band of the frequency band A, and in the second mode for transmitting the second high frequency signal of the transmission frequency band of the frequency band B, the capacitor 312 can be controlled to a second electrostatic capacitance such that the resonance frequency of the LC parallel circuit 31 is included in the transmission frequency band of the frequency band B.

[0137] Accordingly, in the first mode, the resonance frequency of the LC parallel circuit 31 is included in the harmonic frequency band of the transmission frequency band of the frequency band A, and thus the high frequency distortion of the first high frequency signal can be effectively attenuated. On the other hand, in the second mode, the resonance frequency of the LC parallel circuit 31 is included in the transmission frequency band of the frequency band B, and thus the impedance of the LC parallel circuit 31 in the transmission frequency band of the frequency band B can be increased, and the voltage applied to the switches 41 and 42 can be reduced. As a result, the required withstand voltage performance of the switches 41 and 42 can be reduced, and the miniaturization of the switches 41 and 42 can be facilitated.

[0138] Further, for example, in the high-frequency circuit 1 according to the present embodiment, the matching circuit 20 can include a capacitor 21 connected between the power amplification circuit 10 and the harmonic attenuation circuit 30.

[0139] Accordingly, it is possible to cut off the DC component in the matching circuit 20.

[0140] Further, for example, in the high-frequency circuit 1 according to the present embodiment, the matching circuit 20 can include an LC series circuit 22 connected between the path connecting the power amplification circuit 10 and the harmonic attenuation circuit 30 and the ground.

[0141] Accordingly, it is possible to attenuate the high-frequency distortion in the matching circuit 20 as well.

[0142] Further, for example, in the high-frequency circuit 1 according to the present embodiment, the power amplification circuit 10 can include the power amplifiers 11 and 12, and a combiner 13 including an input terminal 131 connected to the output terminal of the power amplifier 11, an input terminal 132 connected to the output terminal of the power amplifier 12, and an output terminal 133 connected to the matching circuit 20.

[0143] Accordingly, it is possible to amplify the high-frequency signal using the power amplifiers 11 and 12 connected in parallel, and it is possible to support higher output power.

[0144] (Modified Example 1 of Embodiment 1)

[0145] Next, Modified Example 1 of Embodiment 1 described above will be described. In the present modified example, the circuit structure of the harmonic attenuation circuit is mainly different from that of Embodiment 1 described above. Hereinafter, with respect to the present modified example, the description will be made focusing on the aspects different from Embodiment 1 described above, with reference to Figure 5A

[0146] Figure 5A is a circuit structure diagram of the harmonic attenuation circuit 30A according to the present modified example. Further, Figure 5A The circuit structure shown is an example, and the harmonic attenuation circuit 30A can be installed using any of a variety of circuit mounting and circuit technologies. Thus, the description of the harmonic attenuation circuit 30A provided below should not be interpreted restrictively.

[0147] The harmonic attenuation circuit 30A is connected between the matching circuit 20 and the switching circuit 40. Specifically, the input terminal of the harmonic attenuation circuit 30A is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuation circuit 30A is connected to the common terminal 400 of the switching circuit 40. The harmonic attenuation circuit 30A can attenuate the harmonics of the signals of the frequency bands A and C.

[0148] ​In the present modification example, the harmonic attenuating circuit 30A includes the inductor 311, and does not include the capacitor 312 connected in parallel to the inductor 311. The inductor 311 is connected between the matching circuit 20 and the switching circuit 40.

[0149] As above, the harmonic attenuating circuit 30A related to the present modification example can include the inductor 311, and can not include the capacitor 312. In this case as well, the harmonic attenuating circuit 30A is able to attenuate harmonics.

[0150] (Modification Example 2 of Embodiment 1)

[0151] Next, Modification Example 2 of Embodiment 1 described above will be explained. In the present modification example, mainly the circuit structure of the harmonic attenuating circuit is different from Embodiment 1 described above. Hereinafter, regarding the present modification example, the explanation will be made focusing on the aspects different from Embodiment 1 described above, with reference to Figure 5B

[0152] Figure 5B is a circuit structure diagram of the harmonic attenuating circuit 30B related to the present modification example. Further, Figure 5B The circuit structure shown is an example, and the harmonic attenuating circuit 30B can be installed using any of a variety of circuit mounting and circuit technologies. Thus, the explanation of the harmonic attenuating circuit 30B provided below should not be interpreted restrictively.

[0153] The harmonic attenuating circuit 30B is connected between the matching circuit 20 and the switching circuit 40. Specifically, the input terminal of the harmonic attenuating circuit 30B is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuating circuit 30B is connected to the common terminal 400 of the switching circuit 40. The harmonic attenuating circuit 30B is able to attenuate harmonics of the signals of the frequency bands A and C.

[0154] In the present modification example, the harmonic attenuating circuit 30B includes the switch 32 in addition to the LC parallel circuit 31. The switch 32 is connected between the matching circuit 20 and the LC parallel circuit 31.

[0155] As above, the harmonic attenuating circuit 30B related to the present modification example can include the switch 32 connected between the matching circuit 20 and the LC parallel circuit 31. Thereby, in the second mode, the influence of the LC parallel circuit 31 on the signal path of the frequency band B can be further reduced by opening the switch 32.

[0156] (Modification Example 3 of Embodiment 1)

[0157] Next, Modification Example 3 of Embodiment 1 described above will be explained. In the present modification example, mainly the circuit structure of the harmonic attenuating circuit is different from Embodiment 1 described above. Hereinafter, regarding the present modification example, the explanation will be made focusing on the aspects different from Embodiment 1 described above, with reference to​Figure 5C The second mode will be described.

[0158] Figure 5C Fig. 32 is a circuit configuration diagram of a harmonic attenuating circuit 30C according to the present modification. Further, the harmonic attenuating circuit 30C is shown as an example of the harmonic attenuating circuit 30 according to the first embodiment. The harmonic attenuating circuit 30C is configured to attenuate harmonics of signals of the frequency bands A and C. Figure 5C The harmonic attenuating circuit 30C can be installed using any of a variety of circuit mounting and circuit technologies. Thus, the description of the harmonic attenuating circuit 30C provided below should not be interpreted restrictively.

[0159] The harmonic attenuating circuit 30C is connected between the matching circuit 20 and the switching circuit 40. Specifically, the input terminal of the harmonic attenuating circuit 30C is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuating circuit 30C is connected to the common terminal 400 of the switching circuit 40. The harmonic attenuating circuit 30C is configured to attenuate harmonics of signals of the frequency bands A and C.

[0160] In the present modification, the harmonic attenuating circuit 30C includes an inductor 311C and a switch 32. The inductor 311C is connected between a path connecting the matching circuit 20 and the switching circuit 40 and ground. The switch 32 is an example of a ninth switch and is connected between the matching circuit 20 and the inductor 311C.

[0161] Further, in the present modification, the switch 32 is connected between the matching circuit 20 and the switching circuit 40, but can be connected between the path connecting the matching circuit 20 and the switching circuit 40 and the inductor 311C. In addition, the harmonic attenuating circuit 30C can further include a capacitor connected in series to the inductor 311C between the path connecting the matching circuit 20 and the switching circuit 40 and ground. In addition, the harmonic attenuating circuit 30C can include a capacitor connected between the path connecting the matching circuit 20 and the switching circuit 40 and ground instead of the inductor 311C. Figure 5C As described above, the harmonic attenuating circuit 30C according to the present modification can include the inductor 311C connected between the path connecting the matching circuit 20 and the switching circuit 41 and ground, and the switch 32 connected between the matching circuit 20 and the inductor 311C.

[0162] Accordingly, in the second mode, the influence of the inductor 311C connected to ground on the signal path of the frequency band B can be reduced by opening the switch 32. In addition, the inductor 311C connected in parallel to the signal path of the frequency bands A and C can reduce the pass loss of the signals of the frequency bands A and C more than the inductor 311 connected in series to the signal path.

[0163] (Embodiment 2)

[0164]

[0165] ​Next, Embodiment 2 will be described. In this embodiment, the main difference from Embodiment 1 is that two additional filters are included in the high-frequency circuit. Hereinafter, regarding this embodiment, we will focus on the aspects that differ from Embodiment 1, referring to… Figure 6 Let me explain.

[0166] Furthermore, the communication device 5A according to this embodiment is the same as the communication device 5 according to the above embodiment 1, except that it has a high-frequency circuit 1A instead of a high-frequency circuit 1. Therefore, its description is omitted.

[0167] [2.1. Circuit structure of high-frequency circuit 1A]

[0168] Reference Figure 6 The circuit structure of the high-frequency circuit 1A involved in this embodiment will be explained below. Furthermore, Figure 6 The circuit structure shown is exemplary. The high-frequency circuit 1A can be installed using any of a wide variety of circuit mounting and circuit techniques. Therefore, the description of the high-frequency circuit 1A provided below should not be interpreted restrictively.

[0169] The high-frequency circuit 1A includes a power amplifier circuit 10, a matching circuit 20, a harmonic attenuation circuit 30, switching circuits 40A and 60A, filters 51, 52, 53 and 54, an antenna connection terminal 100, and a high-frequency input terminal 110.

[0170] [2.1.1. Switching circuit 40A]

[0171] Switching circuit 40A is connected between harmonic attenuation circuit 30 and filters 51-54. Specifically, switching circuit 40A includes common terminals 400 and 403, selection terminals 401, 402, 404 and 405, and switches 41, 42, 43 and 44. Common terminal 400 is connected to the output of harmonic attenuation circuit 30. Common terminal 403 is connected to the output of matching circuit 20 without passing through harmonic attenuation circuit 30. Selection terminal 401 is connected to filter 51. Selection terminal 402 is connected to filter 52. Selection terminal 404 is connected to filter 53. Selection terminal 405 is connected to filter 54.

[0172] Switch 41 is an example of the first switch, connected between the common terminal 400 and the selection terminal 401. That is, switch 41 is connected between the harmonic attenuation circuit 30 and the filter 51.

[0173] The switch 42 is an example of a fourth switch and is connected between the common terminal 400 and the selection terminal 402. That is, the switch 42 is connected between the harmonic attenuating circuit 30 and the filter 52. Further, in a case where the filter 52 is not included in the high-frequency circuit 1A, the switch 42 can also not be included in the switch circuit 40A.

[0174] The switch 43 is an example of a sixth switch and is connected between the common terminal 403 and the selection terminal 404. That is, the switch 43 is connected between the matching circuit 20 and the filter 53 in a manner not via the harmonic attenuating circuit 30.

[0175] The switch 44 is an example of a seventh switch and is connected between the common terminal 403 and the selection terminal 405. That is, the switch 44 is connected between the matching circuit 20 and the filter 54 in a manner not via the harmonic attenuating circuit 30.

[0176] In this connection structure, the switch circuit 40A controls the switches 41 to 44, for example, on the basis of a control signal from the RFIC 3, whereby the common terminal 400 can be selectively connected to the selection terminals 401 and 402, and the common terminal 403 can be selectively connected to the selection terminals 404 and 405. That is, the switch circuit 40A can switch the connection of the harmonic attenuating circuit 30 between the filters 51 and 52, and can switch the connection of the matching circuit 20 between the filters 53 and 54. This switch circuit 40A is constituted by, for example, a DPDT (Double-Pole Double-Throw) type switch circuit.

[0177] The switch circuit 40A, like the switch circuit 40, can be mounted on a semiconductor integrated circuit.

[0178] Further, the circuit structure of the switch circuit 40A is not limited to Figure 6 the circuit structure. The switch circuit 40A can also include one or more additional common terminals and / or one or more additional selection terminals. In this case, the switch circuit 40A can also include one or more additional switches.

[0179] [2.1.2. Filters 53 and 54]

[0180] The filter 53 is an example of a third filter and is a band-pass filter having a passband including a transmission frequency band of the frequency band B. The filter 53 is connected between the switch circuits 40A and 60A. Specifically, one end of the filter 53 is connected to the selection terminal 404 of the switch circuit 40A, and the other end of the filter 53 is connected to the selection terminal 603 of the switch circuit 60A.

[0181] The filter 54 is an example of a fourth filter, and is a bandpass filter having a passband including the transmission frequency band of the frequency band D. The filter 54 is connected between the switch circuits 40A and 60A. Specifically, one end of the filter 54 is connected to the selection terminal 405 of the switch circuit 40A, and the other end of the filter 54 is connected to the selection terminal 604 of the switch circuit 60A. Further, the filter 54 can not be included in the high-frequency circuit 1A.

[0182] As the filters 53 and 54, a SAW filter, a BAW filter, an LC filter, or a dielectric filter, or any combination thereof can be used, and is not limited thereto.

[0183] Further, the filters 53 and 54 are not limited to bandpass filters. Part or all of the filters 53 and 54 can be band elimination filters, or can be highpass filters or lowpass filters.

[0184] [2.1.3. Switch circuit 60A]

[0185] The switch circuit 60A is connected between the filters 51 to 54 and the antenna connection terminal 100. Specifically, the switch circuit 60A includes a common terminal 600, selection terminals 601, 602, 603, and 604, and switches 61, 62, 63, and 64. The common terminal 600 is connected to the antenna connection terminal 100. The selection terminal 601 is connected to the filter 51. The selection terminal 602 is connected to the filter 52. The selection terminal 603 is connected to the filter 53. The selection terminal 604 is connected to the filter 54.

[0186] The switch 61 is an example of a second switch, and is connected between the common terminal 600 and the selection terminal 601. That is, the switch 61 is connected between the antenna connection terminal 100 and the filter 51.

[0187] The switch 62 is an example of a fifth switch, and is connected between the common terminal 600 and the selection terminal 602. That is, the switch 62 is connected between the antenna connection terminal 100 and the filter 52. Further, in the case where the filter 52 is not included in the high-frequency circuit 1A, the switch 62 can not be included in the switch circuit 60A.

[0188] The switch 63 is an example of a third switch, and is connected between the common terminal 600 and the selection terminal 603. That is, the switch 63 is connected between the antenna connection terminal 100 and the filter 53.

[0189] The switch 64 is an example of an eighth switch, and is connected between the common terminal 600 and the selection terminal 604. That is, the switch 64 is connected between the antenna connection terminal 100 and the filter 54.

[0190] In this connection structure, the switch circuit 60A controls the switches 61 to 64 based on a control signal from the RFIC 3, for example, and thereby can selectively connect the common terminal 600 to the selection terminals 601 to 604. That is, the switch circuit 60A can switch the connection of the antenna connection terminal 100 between the filters 51 to 54. This switch circuit 60A is constituted by a switch circuit of SP4T (Single-Pole Quadruple-Throw) type, for example.

[0191] The switch circuit 60A can be mounted in a semiconductor integrated circuit, like the switch circuit 60.

[0192] Further, the circuit structure of the switch circuit 60A is not limited to Figure 6 the circuit structure. The switch circuit 60A can further include one or more additional common terminals and / or one or more additional selection terminals. In this case, the switch circuit 60A can further include one or more additional switches.

[0193] [2.2. Frequency bands]

[0194] Next, the frequency bands A, B, C, and D supported by the communication device 5A will be described.

[0195] The frequency bands A to D are frequency bands of a communication system constructed using a RAT. The frequency bands A to D are defined in advance by a standardization organization or the like (for example, 3GPP and IEEE, and the like). As examples of the communication system, the 5G NR system, the 4G LTE system, the 2G GSM system, and the like can be cited.

[0196] In the present embodiment, the frequency bands A and C are examples of a first frequency band and a third frequency band, respectively, and are 5G NR frequency bands that support a first power class and a second power class. The frequency bands B and D are examples of a second frequency band and a fourth frequency band, respectively, and are 5G NR frequency bands that support the second power class and do not support the first power class. Further, part or all of the frequency bands A to D can be 4G LTE frequency bands.

[0197] The first power class is defined by a first maximum output power that is higher than a second maximum output power, and is referred to as a high power class (HPC) in the present embodiment. The second power class is defined by a second maximum output power that is lower than the first maximum output power, and is referred to as a low power class (LPC) in the present embodiment. For example, as the first power class, a power class 2 or 1.5 is used, and as the second power class, a power class 3 is used.

[0198] [2.3. Multiple communication modes of the communication device 5A]

[0199] Next, the multiple communication modes of the communication device 5A will be described.

[0200] [2.3.1. First Mode]

[0201] First, the first mode included in the plurality of communication modes will be described with reference to Figure 7 The first mode is a communication mode for transmitting a high frequency signal of the transmission band of the frequency band A (an example of the first high frequency signal) with HPC or LPC.

[0202] In the first mode, the switch circuit 40A connects the common terminal 400 to the selection terminal 401 and does not connect the common terminal 400 to the selection terminal 402, and does not connect the common terminal 403 to the selection terminals 404 and 405. That is, the switch 41 is closed, and the switches 42 to 44 are opened. Also, the switch circuit 60A connects the common terminal 600 to the selection terminal 601 and does not connect the common terminal 600 to the selection terminals 602 to 604. That is, the switch 61 is closed, and the switches 62 to 64 are opened.

[0203] Thereby, the transmission signal of the frequency band A is transmitted from the RFIC 3 to the antenna 2 via the high frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the harmonic attenuation circuit 30, the switch circuit 40A, the filter 51, the switch circuit 60A, and the antenna connection terminal 100.

[0204] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to be the first electrostatic capacitance. Thereby, the resonance frequency of the LC parallel circuit 31 is included in the harmonic frequency band of the transmission band of the frequency band A. As a result, the harmonic attenuation circuit 30 can effectively attenuate the signal of the harmonic frequency band of the transmission band of the frequency band A.

[0205] [2.3.2. Second Mode]

[0206] Next, the second mode included in the plurality of communication modes will be described with reference to Figure 8 The second mode is a communication mode for transmitting a high frequency signal of the transmission band of the frequency band B (an example of the second high frequency signal) with LPC.

[0207] In the second mode, the switch circuit 40A connects the common terminal 403 to the selection terminal 404 and does not connect the common terminal 403 to the selection terminal 405, and does not connect the common terminal 400 to the selection terminals 401 and 402. That is, the switch 43 is closed, and the switches 41, 42, and 44 are opened. Also, the switch circuit 60A connects the common terminal 600 to the selection terminal 603 and does not connect the common terminal 600 to the selection terminals 601, 602, and 604. That is, the switch 63 is closed, and the switches 61, 62, and 64 are opened.

[0208] Thus, the transmission signal of the frequency band B is transmitted from the RFIC 3 to the antenna 2 via the high-frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the switch circuit 40A, the filter 53, the switch circuit 60A, and the antenna connection terminal 100. That is, the transmission signal of the frequency band B is transmitted to the antenna 2 without passing through the harmonic attenuation circuit 30.

[0209] [2.3.3. Third Mode]

[0210] Next, the third mode included in the plurality of communication modes will be described with reference to Figure 9 The third mode is a communication mode for transmitting a high-frequency signal of a transmission frequency band of a frequency band C (an example of a third high-frequency signal) in HPC or LPC.

[0211] In the third mode, the switch circuit 40A connects the common terminal 400 to the selection terminal 402 and does not connect the common terminal 400 to the selection terminal 401, and does not connect the common terminal 403 to the selection terminals 404 and 405. That is, the switch 42 is closed, and the switches 41, 43, and 44 are opened. Also, the switch circuit 60A connects the common terminal 600 to the selection terminal 602 and does not connect the common terminal 600 to the selection terminals 601, 603, and 604. That is, the switch 62 is closed, and the switches 61, 63, and 64 are opened.

[0212] Thus, the transmission signal of the frequency band C is transmitted from the RFIC 3 to the antenna 2 via the high-frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the harmonic attenuation circuit 30, the switch circuit 40A, the filter 52, the switch circuit 60A, and the antenna connection terminal 100.

[0213] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to be a third electrostatic capacitance. Thus, the resonance frequency of the LC parallel circuit 31 is included in the harmonic frequency band of the transmission frequency band of the frequency band C. As a result, the harmonic attenuation circuit 30 can effectively attenuate the signal of the harmonic frequency band of the transmission frequency band of the frequency band C.

[0214] [2.3.4. Fourth Mode]

[0215] Next, the fourth mode included in the plurality of communication modes will be described with reference to Figure 10 The fourth mode is a communication mode for transmitting a high-frequency signal of a transmission frequency band of a frequency band D (an example of a fourth high-frequency signal) in LPC.

[0216] In the fourth mode, the switch circuit 40A connects the common terminal 403 with the selection terminal 405 and does not connect the common terminal 403 with the selection terminal 404, and does not connect the common terminal 400 with the selection terminals 401 and 402. That is, the switch 44 is closed, and the switches 41, 42, and 43 are opened. Also, the switch circuit 60A connects the common terminal 600 with the selection terminal 604 and does not connect the common terminal 600 with the selection terminals 601, 602, and 603. That is, the switch 64 is closed, and the switches 61, 62, and 63 are opened.

[0217] Thus, the transmission signal of the frequency band D is transmitted from the RFIC 3 to the antenna 2 via the high-frequency input terminal 110, the power amplification circuit 10, the matching circuit 20, the switch circuit 40A, the filter 54, the switch circuit 60A, and the antenna connection terminal 100, without passing through the harmonic attenuation circuit 30. That is, the transmission signal of the frequency band D is transmitted to the antenna 2 without passing through the harmonic attenuation circuit 30.

[0218] [2.4. SUMMARY]

[0219] As above, the high-frequency circuit 1A according to the present embodiment includes the power amplification circuit 10, the harmonic attenuation circuit 30 having an attenuation frequency band including at least a part of a harmonic frequency band of a transmission frequency band of the frequency band A, the matching circuit 20 connected between the harmonic attenuation circuit 30 and the power amplification circuit 10, the filter 51 having a passband including the transmission frequency band of the frequency band A, the switch 41 connected between the harmonic attenuation circuit 30 and the filter 51, the switch 61 connected between the filter 51 and the antenna connection terminal 100, and the switch 63 connected between the matching circuit 20 and the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30.

[0220] Accordingly, the matching circuit connected to the output terminal of the power amplification circuit 10 is divided into the matching circuit 20 and the harmonic attenuation circuit 30, and a transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30 is realized. Also, the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 via the harmonic attenuation circuit 30 and the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30 can be switched by the switches 41, 61, and 63. Thus, in transmission of a high-frequency signal for which the attenuation of harmonics is strictly required, the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 via the harmonic attenuation circuit 30 is used, and thus the attenuation requirement of harmonics can be satisfied. On the other hand, in transmission of a high-frequency signal for which the attenuation of harmonics is not strictly required, the transmission path in which the matching circuit 20 is connected to the antenna connection terminal 100 without passing through the harmonic attenuation circuit 30 is used, and thus the passage loss of the high-frequency signal in the harmonic attenuation circuit 30 can be reduced. That is, the high-frequency circuit 1A can reduce the passage loss of the high-frequency signal in the harmonic attenuation circuit 30 while satisfying the attenuation requirement of harmonics.

[0221] Also, for example, in the high-frequency circuit 1A according to the present embodiment, the harmonic attenuation circuit 30 can include an inductor connected between the matching circuit 20 and the switch 41, and can not include a ground connection.

[0222] Accordingly, the harmonic attenuation circuit 30 does not include a ground connection, and thus when the switch 41 is open and the switch 63 is closed, the influence of the harmonic attenuation circuit 30 on the signal path of the frequency band B can be suppressed even if the harmonic attenuation circuit 30 does not include a switch. Also, the inductor 311 is connected between the matching circuit 20 and the switch 41, and thus the passage loss of the inductor 311 is large, and the effect of reducing the passage loss of the high-frequency signal in the harmonic attenuation circuit 30 is large.

[0223] Also, for example, the high-frequency circuit 1A according to the present embodiment can further include a filter 52 having a passband including a transmission frequency band of a frequency band C, a switch 42 connected between the harmonic attenuation circuit 30 and the filter 52, and a switch 62 connected between the filter 52 and the antenna connection terminal 100.

[0224] Accordingly, the high-frequency signal of the frequency band C can be transmitted via the harmonic attenuation circuit 30, the attenuation requirement of harmonics can be satisfied in transmission of a signal of the frequency band C in addition to the frequency band A, and the passage loss of the signal of the frequency band B in the harmonic attenuation circuit 30 can be reduced in transmission of a signal of the frequency band B.

[0225] Further, for example, the high-frequency circuit 1A according to the present embodiment can further include a switch 43 connected between the matching circuit 20 and the switch 63 without passing through the harmonic attenuating circuit 30, and a filter 53 connected between the switch 63 and the switch 43, having a passband including the transmission frequency band of the frequency band B.

[0226] Accordingly, the signal of the frequency band B can be transmitted via the filter 53, and thus the spurious emission in the transmission of the signal of the frequency band B can be reduced.

[0227] Further, for example, the high-frequency circuit 1A according to the present embodiment can further include a filter 54 having a passband including the transmission frequency band of the frequency band D, a switch 44 connected between the matching circuit 20 and the filter 54 without passing through the harmonic attenuating circuit 30, and a switch 64 connected between the filter 54 and the antenna connection terminal 100.

[0228] Accordingly, the high-frequency signal of the frequency band D can be transmitted without passing through the harmonic attenuating circuit 30, and the pass loss of the signal of the frequency band D in the harmonic attenuating circuit 30 can be reduced in the transmission of the signal of the frequency band D in addition to the frequency band B.

[0229] Further, for example, in the high-frequency circuit 1A according to the present embodiment, in a first mode for transmitting the first high-frequency signal of the transmission frequency band of the frequency band A, the switches 41 and 61 can be closed, and the switches 63, 42, 62, 43, 44, and 64 can be opened, in a second mode for transmitting the second high-frequency signal of the transmission frequency band of the frequency band B, the switches 63 and 43 can be closed, and the switches 41, 61, 42, 62, 44, and 64 can be opened, in a third mode for transmitting the third high-frequency signal of the transmission frequency band of the frequency band C, the switches 42 and 62 can be closed, and the switches 41, 61, 63, 43, 44, and 64 can be opened, and in a fourth mode for transmitting the fourth high-frequency signal of the transmission frequency band of the frequency band D, the switches 44 and 64 can be closed, and the switches 41, 61, 63, 42, 62, and 43 can be opened.

[0230] Accordingly, the first mode and the third mode are used in a case where the attenuation of harmonics is strictly required, and thus the high-frequency signal can be transmitted via the harmonic attenuating circuit 30. On the other hand, the second mode and the fourth mode are used in a case where the attenuation of harmonics is not strictly required, and thus the high-frequency signal can be transmitted without passing through the harmonic attenuating circuit 30. Thus, for the transmission of the first high-frequency signal and the third high-frequency signal for which the attenuation of harmonics is strictly required, the attenuation of harmonics can be satisfied, and in the transmission of the second high-frequency signal and the fourth high-frequency signal for which the attenuation of harmonics is not strictly required, the pass loss of the high-frequency signal in the harmonic attenuating circuit 30 can be reduced.

[0231] Further, for example, in the high-frequency circuit 1A according to the present embodiment, the frequency band A and the frequency band C can also be 5G NR bands or 4G LTE bands that support a first power class defined by a first maximum output power and a second power class defined by a second maximum output power lower than the first maximum output power, and the frequency band B and the frequency band D can also be 5G NR bands or 4G LTE bands that support the second power class and do not support the first power class.

[0232] Accordingly, it is possible to satisfy the attenuation requirement of harmonics in the first power class in which the attenuation requirement of harmonics is stricter, and it is possible to reduce the transmission loss of high-frequency signals in the second power class in which the attenuation requirement of harmonics is looser.

[0233] Further, for example, in the high-frequency circuit 1A according to the present embodiment, the harmonic attenuation circuit 30 can also include an LC parallel circuit 31 connected between the matching circuit 20 and the switch 41.

[0234] Accordingly, it is possible to attenuate harmonics using the LC parallel circuit 31.

[0235] Further, for example, in the high-frequency circuit 1A according to the present embodiment, the matching circuit 20 can also include a capacitor 21 connected between the power amplification circuit 10 and the harmonic attenuation circuit 30.

[0236] Accordingly, it is possible to cut off the direct current component in the matching circuit 20.

[0237] Further, for example, in the high-frequency circuit 1A according to the present embodiment, the matching circuit 20 can also include an LC series circuit 22 connected between the path connecting the power amplification circuit 10 and the harmonic attenuation circuit 30 and the ground.

[0238] Accordingly, it is possible to further attenuate high-frequency distortion in the matching circuit 20.

[0239] Further, for example, in the high-frequency circuit 1A according to the present embodiment, the power amplification circuit 10 can also include the power amplifiers 11 and 12, and a combiner 13 including an input terminal 131 connected to the output terminal of the power amplifier 11, an input terminal 132 connected to the output terminal of the power amplifier 12, and an output terminal 133 connected to the matching circuit 20.

[0240] Accordingly, it is possible to amplify high-frequency signals using the power amplifiers 11 and 12 connected in parallel, and it is possible to support higher output power.

[0241] (Other Embodiments)

[0242] The above describes the high-frequency circuit according to the present application based on the embodiments, but the high-frequency circuit according to the present application is not limited to the above-described embodiments. Other embodiments achieved by combining any of the structural elements of the above-described embodiments, modified examples of the above-described embodiments achieved by making various changes to the above-described embodiments within the scope of the present application without departing from the spirit of the present application, and various devices in which the above-described high-frequency circuit is built-in are also included in the present application.

[0243] For example, in the circuit structure of the high-frequency circuit according to each of the above-described embodiments, other circuit elements and wirings or the like can be inserted between the paths connecting the respective circuit elements and the signal paths disclosed in the drawings. For example, an impedance matching circuit can be connected between the filters 51 and 52 and the switching circuit 60. Further, for example, a coupler can be connected between the switching circuit 60 and the antenna connection terminal 100.

[0244] Further, for example, the modified examples 1 to 3 of the embodiment 1 can be applied to the embodiment 2. That is, the high-frequency circuit 1A can be provided with the harmonic attenuation circuit 30A, 30B, or 30C instead of the harmonic attenuation circuit 30.

[0245] Next, the features of the high-frequency circuit described based on each of the above-described embodiments are shown.

[0246] <1>

[0247] A high-frequency circuit includes:

[0248] a power amplification circuit;

[0249] a harmonic attenuation circuit having an attenuation frequency band including at least a part of a harmonic frequency band of a transmission frequency band of a first frequency band;

[0250] a matching circuit connected between the harmonic attenuation circuit and the power amplification circuit;

[0251] a first filter having a passband including the transmission frequency band of the first frequency band;

[0252] a first switch connected between the harmonic attenuation circuit and the first filter;

[0253] a second switch connected between the first filter and an antenna connection terminal; and

[0254] a third switch connected between the matching circuit and the antenna connection terminal without passing through the harmonic attenuation circuit.

[0255] <2>

[0256] The high-frequency circuit according to <1>, wherein

[0257] The harmonic attenuation circuit includes an inductor connected between the matching circuit and the first switch, but does not include a ground connection.

[0258] <3>

[0259] according to <1> or <2> The high-frequency circuit, wherein,

[0260] In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the first switch and the second switch are closed, and the third switch is open.

[0261] In the second mode for transmitting a second high-frequency signal in the transmission band of the second frequency band, the third switch is closed, and the first switch and the second switch are open.

[0262] <4>

[0263] according to <3> The high-frequency circuit, wherein,

[0264] The first frequency band is either the 5G NR band or the 4G LTE band.

[0265] The second frequency band is the 2G GSM band.

[0266] <5>

[0267] according to <3> The high-frequency circuit, wherein,

[0268] The first frequency band and the second frequency band are either 5G NR bands or 4G LTE bands.

[0269] The maximum output power of the first high-frequency signal is higher than the maximum output power of the second high-frequency signal.

[0270] <6>

[0271] according to <4> or <5> The high-frequency circuit, wherein,

[0272] The high-frequency circuit also features:

[0273] The second filter has a passband that includes the transmission band of the third frequency band;

[0274] A fourth switch, connected between the harmonic attenuation circuit and the second filter; and

[0275] The fifth switch is connected between the second filter and the antenna connection terminal.

[0276] <7>

[0277] according to <6> The high-frequency circuit, wherein,

[0278] In the third mode for transmitting the third high-frequency signal of the transmission band of the third frequency band, the fourth switch and the fifth switch are closed, and the first switch, the second switch and the third switch are open.

[0279] <8>

[0280] according to <1> or <2> The high-frequency circuit, wherein,

[0281] The high-frequency circuit also features:

[0282] The second filter has a passband that includes the transmission band of the third frequency band;

[0283] A fourth switch, connected between the harmonic attenuation circuit and the second filter; and

[0284] The fifth switch is connected between the second filter and the antenna connection terminal.

[0285] <9>

[0286] according to <8> The high-frequency circuit, wherein,

[0287] The high-frequency circuit also features:

[0288] A sixth switch, which is connected between the matching circuit and the third switch without passing through the harmonic attenuation circuit; and

[0289] The third filter, connected between the third switch and the sixth switch, has a passband that includes the transmission band of the second frequency band.

[0290] <10>

[0291] according to <9> The high-frequency circuit, wherein,

[0292] The high-frequency circuit also features:

[0293] The fourth filter has a passband that includes the transmission band of the fourth frequency band;

[0294] A seventh switch, which is connected between the matching circuit and the fourth filter without passing through the harmonic attenuation circuit; and

[0295] The eighth switch is connected between the fourth filter and the antenna connection terminal.

[0296] <11>

[0297] according to <10> The high-frequency circuit, wherein,

[0298] In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the first switch and the second switch are closed, and the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, and the eighth switch are open.

[0299] In the second mode for transmitting the second high-frequency signal of the second frequency band, the third switch and the sixth switch are closed, and the first switch, the second switch, the fourth switch, the fifth switch, the seventh switch, and the eighth switch are open.

[0300] In the third mode for transmitting the third high-frequency signal of the third frequency band, the fourth and fifth switches are closed, and the first, second, third, sixth, seventh, and eighth switches are open.

[0301] In the fourth mode for transmitting the fourth high-frequency signal of the transmission band of the fourth frequency band, the seventh switch and the eighth switch are closed, and the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are open.

[0302] <12>

[0303] according to <11> The high-frequency circuit, wherein,

[0304] The first frequency band and the third frequency band are 5G NR bands or 4G LTE bands that support a first power level defined by a first maximum output power and a second power level defined by a second maximum output power lower than the first maximum output power.

[0305] The second frequency band and the fourth frequency band are 5G NR bands or 4G LTE bands that support the second power level but do not support the first power level.

[0306] <13>

[0307] according to <1> ~ <12> The high-frequency circuit described in any one of the above, wherein,

[0308] The harmonic attenuation circuit includes an LC parallel circuit connected between the matching circuit and the first switch.

[0309] <14>

[0310] according to <13> The high-frequency circuit, wherein,

[0311] The capacitor in the LC parallel circuit is a variable capacitor.

[0312] <15>

[0313] according to <14> The high-frequency circuit, wherein,

[0314] In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the variable capacitor is controlled as a first electrostatic capacitor.

[0315] In the second mode for transmitting a second high-frequency signal in the transmission band of the second frequency band, the variable capacitor is controlled to be a second electrostatic capacitance larger than the first electrostatic capacitance.

[0316] <16>

[0317] according to <15> The high-frequency circuit, wherein,

[0318] In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the variable capacitor is controlled to be the first electrostatic capacitance, such that the resonant frequency of the LC parallel circuit is included in the harmonic band of the transmission band of the first frequency band.

[0319] In a second mode for transmitting a second high-frequency signal in the transmission band of the second frequency band, the variable capacitor is controlled as the second electrostatic capacitor, such that the resonant frequency of the LC parallel circuit is included in the transmission band of the second frequency band.

[0320] <17>

[0321] according to <1> The high-frequency circuit, wherein,

[0322] The harmonic attenuation circuit includes:

[0323] At least one of the inductor and capacitor connected to ground along the path connecting the matching circuit and the first switch; and

[0324] A ninth switch connected between the matching circuit and at least one of the inductor and the capacitor.

[0325] <18>

[0326] according to <1> ~ <17> The high-frequency circuit described in any one of the above, wherein,

[0327] The matching circuit includes a capacitor connected between the power amplifier circuit and the harmonic attenuation circuit.

[0328] <19>

[0329] according to <1> ~ <18> The high-frequency circuit described in any one of the above, wherein,

[0330] The matching circuit includes an LC series circuit connected to the same ground along the path connecting the power amplifier circuit and the harmonic attenuation circuit.

[0331] <20>

[0332] according to <1> ~ <19> The high-frequency circuit described in any one of the above, wherein,

[0333] The power amplifier circuit includes:

[0334] First power amplifier and second power amplifier; and

[0335] The synthesizer includes a first input terminal connected to the output of the first power amplifier, a second input terminal connected to the output of the second power amplifier, and an output terminal connected to the matching circuit.

[0336] Industrial availability

[0337] As a high-frequency circuit configured in the front end, this invention can be widely used in communication devices such as portable telephones.

[0338] Explanation of reference numerals in the attached figures

[0339] 1, 1A: High-frequency circuit; 2: Antenna; 3: RFIC; 4: BBIC; 5, 5A: Communication device; 10: Power amplifier circuit; 11, 12: Power amplifier; 13: Synthesizer; 14: Distributor; 20: Matching circuit; 21, 221: Capacitor; 22: LC series circuit; 30, 30A, 30B, 30C: Harmonic attenuation circuit; 31: LC parallel circuit; 32, 41, 42, 43, 44, 61, 62, 63, 64: Switch; 40, 40 A, 60, 60A: Switching circuit; 51, 52, 53, 54: Filter; 100: Antenna connection terminal; 110: High-frequency input terminal; 131, 132, 141: Input terminals; 133, 142, 143: Output terminals; 222, 311, 311C: Inductors; 312: Capacitor; 400, 403, 600: Common terminals; 401, 402, 404, 405, 601, 602, 603, 604: Selection terminals; N23: Node.

Claims

1. A high-frequency circuit, comprising: Power amplifier circuit; A harmonic attenuation circuit having an attenuation band that includes at least a portion of the harmonic band of the transmission band of a first frequency band. A matching circuit is connected between the harmonic attenuation circuit and the power amplifier circuit; A first filter having a passband that includes the transmission frequency band of the first frequency band; A first switch is connected between the harmonic attenuation circuit and the first filter; The second switch is connected between the first filter and the antenna connection terminal; as well as The third switch is connected between the matching circuit and the antenna connection terminal without passing through the harmonic attenuation circuit.

2. The high-frequency circuit according to claim 1, wherein, The harmonic attenuation circuit includes an inductor connected between the matching circuit and the first switch, but does not include a ground connection.

3. The high-frequency circuit according to claim 1 or 2, wherein, In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the first switch and the second switch are closed, and the third switch is open. In the second mode for transmitting a second high-frequency signal in the transmission band of the second frequency band, the third switch is closed, and the first switch and the second switch are open.

4. The high-frequency circuit according to claim 3, wherein, The first frequency band is either the 5G NR band or the 4G LTE band. The second frequency band is the 2G GSM band.

5. The high-frequency circuit according to claim 3, wherein, The first frequency band and the second frequency band are either 5G NR bands or 4G LTE bands. The maximum output power of the first high-frequency signal is higher than the maximum output power of the second high-frequency signal.

6. The high-frequency circuit according to claim 4 or 5, wherein, The high-frequency circuit also features: The second filter has a passband that includes the transmission band of the third frequency band; A fourth switch, connected between the harmonic attenuation circuit and the second filter; and The fifth switch is connected between the second filter and the antenna connection terminal.

7. The high-frequency circuit according to claim 6, wherein, In the third mode for transmitting the third high-frequency signal of the transmission band of the third frequency band, the fourth switch and the fifth switch are closed, and the first switch, the second switch and the third switch are open.

8. The high-frequency circuit according to claim 1 or 2, wherein, The high-frequency circuit also features: The second filter has a passband that includes the transmission band of the third frequency band; A fourth switch, connected between the harmonic attenuation circuit and the second filter; and The fifth switch is connected between the second filter and the antenna connection terminal.

9. The high-frequency circuit according to claim 8, wherein, The high-frequency circuit also features: A sixth switch, which is connected between the matching circuit and the third switch without passing through the harmonic attenuation circuit; and The third filter, connected between the third switch and the sixth switch, has a passband that includes the transmission band of the second frequency band.

10. The high-frequency circuit according to claim 9, wherein, The high-frequency circuit also features: The fourth filter has a passband that includes the transmission band of the fourth frequency band; The seventh switch is connected between the matching circuit and the fourth filter without passing through the harmonic attenuation circuit; as well as The eighth switch is connected between the fourth filter and the antenna connection terminal.

11. The high-frequency circuit according to claim 10, wherein, In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the first switch and the second switch are closed, and the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, and the eighth switch are open. In the second mode for transmitting the second high-frequency signal of the second frequency band, the third switch and the sixth switch are closed, and the first switch, the second switch, the fourth switch, the fifth switch, the seventh switch, and the eighth switch are open. In the third mode for transmitting the third high-frequency signal of the third frequency band, the fourth and fifth switches are closed, and the first, second, third, sixth, seventh, and eighth switches are open. In the fourth mode for transmitting the fourth high-frequency signal of the transmission band of the fourth frequency band, the seventh switch and the eighth switch are closed, and the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are open.

12. The high-frequency circuit according to claim 11, wherein, The first frequency band and the third frequency band are 5G NR bands or 4G LTE bands that support a first power level defined by a first maximum output power and a second power level defined by a second maximum output power lower than the first maximum output power. The second frequency band and the fourth frequency band are 5G NR bands or 4G LTE bands that support the second power level but do not support the first power level.

13. The high-frequency circuit according to any one of claims 1 to 12, wherein, The harmonic attenuation circuit includes an LC parallel circuit connected between the matching circuit and the first switch.

14. The high-frequency circuit according to claim 13, wherein, The capacitor in the LC parallel circuit is a variable capacitor.

15. The high-frequency circuit according to claim 14, wherein, In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the variable capacitor is controlled as a first electrostatic capacitor. In the second mode for transmitting a second high-frequency signal in the transmission band of the second frequency band, the variable capacitor is controlled to be a second electrostatic capacitance larger than the first electrostatic capacitance.

16. The high-frequency circuit according to claim 15, wherein, In a first mode for transmitting a first high-frequency signal in the transmission band of the first frequency band, the variable capacitor is controlled to be the first electrostatic capacitance, such that the resonant frequency of the LC parallel circuit is included in the harmonic band of the transmission band of the first frequency band. In a second mode for transmitting a second high-frequency signal in the transmission band of the second frequency band, the variable capacitor is controlled as the second electrostatic capacitor, such that the resonant frequency of the LC parallel circuit is included in the transmission band of the second frequency band.

17. The high-frequency circuit according to claim 1, wherein, The harmonic attenuation circuit includes: At least one of the inductor and capacitor connected to ground along the path connecting the matching circuit and the first switch; and A ninth switch connected between the matching circuit and at least one of the inductor and the capacitor.

18. The high-frequency circuit according to any one of claims 1 to 17, wherein, The matching circuit includes a capacitor connected between the power amplifier circuit and the harmonic attenuation circuit.

19. The high-frequency circuit according to any one of claims 1 to 18, wherein, The matching circuit includes an LC series circuit connected to the same ground along the path connecting the power amplifier circuit and the harmonic attenuation circuit.

20. The high-frequency circuit according to any one of claims 1 to 19, wherein, The power amplifier circuit includes: First power amplifier and second power amplifier; and The synthesizer includes a first input terminal connected to the output of the first power amplifier, a second input terminal connected to the output of the second power amplifier, and an output terminal connected to the matching circuit.

Images