High-frequency circuit and communication device

A high-frequency circuit includes a power amplifier for a communication band A, and a power amplifier for a communication band B. Transmission in the communication band A, transmission in the communication band B, and reception in the communication band C can be simultaneously used. A frequency range of intermodulation distortion generated between a second harmonic wave of a transmission signal of the communication band A and a fundamental wave of a transmission signal of the communication band B, overlaps with at least part of a reception band of the communication band C. The power amplifier includes amplifying elements and an output trans including coils. One end of the coil is connected with an output of the amplifying element, the other end of the coil is connected with an output of the amplifying element, and one end of the coil is connected with an output terminal of the power amplifier.

BACKGROUND ART

Technical Field

The present disclosure relates to a high-frequency circuit and a communication device.

With the progress of multiband technology, mobile communication equipment such as mobile phones have been required to have a front end circuit that is capable of simultaneously transmitting high-frequency signals having mutually-different frequencies. For example, Patent Document 1 discloses a circuit configuration of an electronic system (high-frequency front end module) including a first transmission circuit and a second transmission circuit.

BRIEF SUMMARY

In the above-mentioned related art, however, when a plurality of high-frequency signals are simultaneously transmitted and simultaneously transmitted and received, intermodulation distortion (IMD) among the plurality of high-frequency signals overlaps with a reception band and receiving sensitivity sometimes degrades disadvantageously.

Therefore, the present disclosure provides a high-frequency circuit and a communication device that are capable of suppressing degradation of receiving sensitivity caused by intermodulation distortion in simultaneous transmission and simultaneous transmission and reception of a plurality of high-frequency signals.

A high-frequency circuit of an aspect of the present disclosure includes: a first filter that has a pass band including a transmission band of a first communication band; a second filter that has a pass band including a transmission band of a second communication band which is different from the first communication band; a third filter that has a pass band including a reception band of a third communication band; a first power amplifier that is connected with the first filter; and a second power amplifier that is connected with the second filter. Transmission in the first communication band, transmission in the second communication band, and reception in the third communication band can be simultaneously used. At least part of a frequency range of intermodulation distortion, which is generated between a second harmonic wave of a transmission signal of the first communication band and a fundamental wave of a transmission signal of the second communication band, overlaps with at least part of the reception band of the third communication band. The first power amplifier includes a first amplifying element, a second amplifying element, and an output converter that is a first transformer including a first coil and a second coil. One end of the first coil is connected with an output of the first amplifying element, the other end of the first coil is connected with an output of the second amplifying element, and one end of the second coil is connected with an output terminal of the first power amplifier.

According to the high-frequency circuit of the aspect of the present disclosure, degradation of receiving sensitivity caused by intermodulation distortion can be suppressed when a plurality of high-frequency signals are simultaneously transmitted and simultaneously transmitted and received.

DETAILED DESCRIPTION

Embodiments according to the present disclosure will be described in detail below with reference to the accompanying drawings. All of the embodiments described below are generic or specific examples. Numerical values, shapes, materials, components, arrangement and connection forms of the components, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure.

Each drawing is a schematic diagram with emphasis, omission, or proportion adjustment performed as appropriate to illustrate the present disclosure. Thus, each drawing is not necessarily a strict illustration and may differ from the actual shapes, positioning, and proportions. In each drawing, the same reference characters are applied to substantially identical configurations and redundant description may be omitted or simplified.

In the circuit configuration of the present disclosure, “connected” includes not only direct connection by connection terminals and/or wiring conductors, but also electrical connection via other circuit elements. “Connected between A and B” means being connected with both of A and B between A and B.

EMBODIMENT

Circuit configurations of a high-frequency circuit1and a communication device5according to the present embodiment will be described with reference toFIG.1.FIG.1is a circuit configuration diagram of the high-frequency circuit1and the communication device5according to the embodiment.

1.1.1 Circuit Configuration of Communication Device5

The circuit configuration of the communication device5will be first described. As illustrated inFIG.1, the communication device5according to the present embodiment includes the high-frequency circuit1, an antenna2, an RFIC3, and a BBIC4.

The high-frequency circuit1transmits a high-frequency signal between the antenna2and the RFIC3. The circuit configuration of the high-frequency circuit1will be described later.

The antenna2is connected with an antenna connection terminal100of the high-frequency circuit1. The antenna2receives a high-frequency signal from the outside and outputs the high-frequency signal to the high-frequency circuit1.

The RFIC3is an example of a signal processing circuit that processes a high-frequency signal. Specifically, the RFIC3processes a high-frequency reception signal, inputted via a reception path of the high-frequency circuit1, by down-conversion or the like and outputs the reception signal generated by this signal processing to the BBIC4. Further, the RFIC3includes a control unit that controls switches, amplifiers, and the like included in the high-frequency circuit1. Here, part or all of the function as the control unit of the RFIC3may be mounted on the outside of the RFIC3, and may be mounted, for example, on the BBIC4or the high-frequency circuit1.

The BBIC4is a baseband signal processing circuit that processes a signal by using an intermediate frequency band which is lower in frequency than the high-frequency signal transmitted by the high-frequency circuit1. Examples of a signal processed in the BBIC4include an image signal for displaying an image and/or an audio signal for calls through speakers.

In the communication device5according to the present embodiment, the antenna2and the BBIC4are optional components.

The circuit configuration of the high-frequency circuit1will now be described. As illustrated inFIG.1, the high-frequency circuit1includes power amplifiers11and12, a low noise amplifier21, a switch51, filters61to63, the antenna connection terminal100, high-frequency input terminals111and112, and a high-frequency output terminal121.

The antenna connection terminal100is connected to the antenna2.

Each of the high-frequency input terminals111and112is a terminal for receiving a high-frequency transmission signal from the outside of the high-frequency circuit1. The high-frequency input terminal111can receive a transmission signal of a communication band A from the RFIC3. The high-frequency input terminal112can receive a transmission signal of a communication band B from the RFIC3. In the present embodiment, both of transmission signals received at the high-frequency input terminals111and112are unbalanced signals.

The high-frequency output terminal121is a terminal for providing a high-frequency reception signal to the outside of the high-frequency circuit1. Specifically, the high-frequency output terminal121is a terminal for providing a reception signal of a communication band C to the RFIC3.

The communication band means a frequency band predefined by a standards body (for example, 3rd Generation Partnership Project (3GPP) and Institute of Electrical and Electronics Engineers (IEEE)) or the like for communication systems.

Here, the communication systems mean communication systems built by using the radio access technology (RAT). Examples of the communication systems include 5th generation new radio (5GNR) systems, long term evolution (LTE) systems, and wireless local area network (WLAN) systems, but the communication systems are not limited to these.

The communication band A is an example of a first communication band. The communication band B is an example of a second communication band and is a different frequency band from the communication band A. The communication band C is an example of a third communication band. The communication band C may be the same as either one of the communication bands A and B or may be different from the communication bands A and B. The communication bands A, B, and C may be either a frequency division duplex (FDD) communication band or a time division duplex (TDD) communication band.

Here, transmission in the communication band A, transmission in the communication band B, and reception in the communication band C can be simultaneously used. “Transmission in the communication band A, transmission in the communication band B, and reception in the communication band C can be simultaneously used” means that a transmission signal of the communication band A, a transmission signal of the communication band B, and a reception signal of the communication band C are allowed to be simultaneously transmitted and received. However, it is not excluded that transmission and reception of a plurality of communication bands are each used independently. A combination of communication bands that can be simultaneously used is predefined by, for example, a standards body.

The power amplifier11is an example of a first power amplifier. An input terminal115of the power amplifier11is connected with the high-frequency input terminal111and an output terminal116of the power amplifier11is connected with the filter61. The power amplifier11is capable of amplifying a transmission signal of the communication band A received at the high-frequency input terminal111. At this time, the power amplifier11is capable of converting an unbalanced signal received at the high-frequency input terminal111into a balanced signal and amplifying the balanced signal. This kind of power amplifier11is sometimes called a differential amplifier. The detailed configuration of the power amplifier11will be described later with reference toFIG.2.

A balanced signal means a pair of signals that have mutually-opposite phases. A balanced signal is sometimes called a differential signal. On the other hand, an unbalanced signal means a signal expressed by a potential difference from ground. An unbalanced signal is sometimes called a single end signal.

The power amplifier12is an example of a second power amplifier. An input terminal125of the power amplifier12is connected with the high-frequency input terminal112and an output terminal126of the power amplifier12is connected with the filter62. The power amplifier12is a multi-stage amplifier and includes two amplifying elements12A and12B which are connected in series. The amplifying element12A is equivalent to an input stage of a multi-stage amplifier. The amplifying element12B is equivalent to an output stage of a multi-stage amplifier.

The power amplifier12is capable of amplifying a transmission signal of the communication band B received at the high-frequency input terminal112. At this time, the power amplifier12is capable of amplifying the transmission signal of the communication band B as an unbalanced signal without necessarily conversion. That is, the power amplifier12is capable of amplifying an unbalanced signal of the communication band B received at the high-frequency input terminal111without necessarily converting the unbalanced signal into a balanced signal. This kind of power amplifier12is sometimes called a non-differential amplifier.

The configuration of the power amplifier12is not limited to the configuration ofFIG.1. For example, the power amplifier12may be a single-stage amplifier. Alternatively, the power amplifier12may be a differential amplifier or a Doherty amplifier.

The power amplifiers11and12correspond to a high-power class and a non-high-power class respectively. A power class is a classification of terminal output power which is defined as maximum output power or the like, and a smaller power class value indicates that it corresponds to higher power output. The maximum output power of a high-power class is larger than the maximum output power of a non-high-power class. The maximum output power is defined by output power at an antenna end of a terminal. The maximum output power is measured by a method defined by, for example, 3GPP. For example, the maximum output power is measured by measuring radiation power of the antenna2, inFIG.1. Instead of measuring radiation power, output power of the antenna2can be measured by providing a terminal near the antenna2and connecting a measuring instrument (such as a spectrum analyzer) to the terminal.

The high-power class is an example of a first power class and is expressed by a numerical value which is lower than a predetermined value. The non-high-power class is an example of a second power class and is expressed by a numerical value which is a predetermined value or greater. The predetermined value can be, for example, 3. In this case, the high-power class includes power classes 1, 1.5, and 2, and the non-high-power class includes power classes 3 and 4.

An input of the low noise amplifier21is connected with the filter63and an output of the low noise amplifier21is connected with the high-frequency output terminal121. The low noise amplifier21is capable of amplifying a reception signal of the communication band C received at the antenna connection terminal100. The reception signal of the communication band C amplified by the low noise amplifier21is outputted to the high-frequency output terminal121.

Amplifying elements included in the power amplifiers11and12and low noise amplifier21can be composed of, for example, a field effect transistor (FET) or a hetero bipolar transistor (HBT) that is made of Si-based complementary metal oxide semiconductor (CMOS) or GaAs.

The switch51is connected between the antenna connection terminal100and the filters61to63. The switch51includes terminals511to514. The terminal511is connected with the antenna connection terminal100. The terminals512to514are connected with the filters61to63respectively.

In this connection configuration, the switch51is capable of connecting at least one of the terminals512to514to the terminal511in response to, for example, a control signal from the RFIC3. That is, the switch51is capable of switching connection and disconnection between the antenna connection terminal100and each of the filters61to63. The switch51is composed of, for example, a multi-connection switching circuit and is called an antenna switch.

The filter61(A-Tx) is an example of a first filter and has a pass band including the transmission band of the communication band A. One end of the filter61is connected with the antenna connection terminal100via the switch51. The other end of the filter61is connected with the output terminal116of the power amplifier11.

The filter62(B-Tx) is an example of a second filter and has a pass band including the transmission band of the communication band B. One end of the filter62is connected with the antenna connection terminal100via the switch51. The other end of the filter62is connected with the output terminal126of the power amplifier12.

The filter63(C-Rx) is an example of a third filter and has a pass band including the reception band of the communication band C. One end of the filter63is connected with the antenna connection terminal100via the switch51. The other end of the filter63is connected with the input of the low noise amplifier21.

A transmission band is a frequency band for transmission in a communication band. As to a communication band for FDD, its transmission band is equivalent to an uplink operating band which is a portion in the communication band designated for uplink. As to a communication band for TDD, its transmission band is equivalent to the entire communication band.

A reception band is a frequency band for reception in a communication band. As to a communication band for FDD, its reception band is equivalent to a downlink operating band which is a portion in the communication band designated for downlink. As to a communication band for TDD, its reception band is equivalent to the entire communication band.

These filters61to63may be any of an acoustic wave filter using a surface acoustic wave (SAW), an acoustic wave filter using a bulk acoustic wave (BAW), an LC resonance filter, and a dielectric filter, for example, and further, the filters61to63are not limited to these.

Some of the circuit elements illustrated inFIG.1do not have to be included in the high-frequency circuit1. For example, the high-frequency circuit1just has to include at least the power amplifiers11and12and the filters61to63, and does not have to include other circuit elements (such as the switch51and the low noise amplifier21).

1.1.3 Circuit Configuration of Power Amplifier11

An example of the circuit configuration of the power amplifier11will now be described with reference toFIG.2.FIG.2is a circuit configuration diagram of the power amplifier11included in the high-frequency circuit1according to the embodiment. Hereinafter, a transformer is abbreviated as a trans.

As illustrated inFIG.2, the power amplifier11includes the input terminal115, the output terminal116, amplifying elements11A to11C, an output trans31, a capacitor32, and an input trans33.

The input terminal115is connected with the high-frequency input terminal111of the high-frequency circuit1. An unbalanced signal received at the high-frequency input terminal111from the outside is transmitted to the input terminal115.

The amplifying element11C is equivalent to an input stage of a multi-stage amplifier. An input of the amplifying element11C is connected with the input terminal115of the power amplifier11, and an output of the amplifying element11C is connected with the input trans33. In this connection configuration, the amplifying element11C is capable of amplifying an unbalanced signal received at the input terminal115in a state that a power supply voltage Vcc1 is applied.

The input trans33is an example of an input converter. The input trans33includes a coil33aon the primary side and a coil33bon the secondary side. The coil33ais an example of a third coil. One end of the coil33ais connected with an output terminal of the amplifying element11C, and the power supply voltage Vcc1 is applied to the other end. The coil33bis an example of a fourth coil. One end of the coil33bis connected with an input of the amplifying element11A, and the other end is connected with an input of the amplifying element11B.

The input trans33is capable of converting an unbalanced signal amplified in the amplifying element11C into a balanced signal. That is, the input trans33is an unbalance-balance converter. Specifically, the input trans33is capable of converting a transmission signal of the communication band A amplified in the amplifying element11C into an inverted signal whose phase is inverted and a non-inverted signal whose phase is not inverted.

The amplifying elements11A and11B are examples of a first amplifying element and a second amplifying element respectively and are capable of individually amplifying balanced signals outputted from the input trans33. The input of the amplifying element11A is connected with one end of the coil33bof the input trans33, and an output of the amplifying element11A is connected with one end of a coil31aof the output trans31and one end of the capacitor32. The input of the amplifying element11B is connected with the other end of the coil33bof the input trans33, and an output of the amplifying element11B is connected with the other end of the coil31aof the output trans31and the other end of the capacitor32.

The output trans31is an example of an output converter. The output trans31includes the coil31aon the primary side and a coil31bon the secondary side. The coil31ais an example of a first coil. One end of the coil31ais connected with the output of the amplifying element11A, and the other end is connected with the output of the amplifying element11B. Further, a power supply voltage Vcc2 is applied to a midpoint of the coil31a. The coil31bis an example of a second coil. One end of the coil31bis connected with the output terminal116, and the other end is connected to the ground. That is, the output trans31is connected between the output of the amplifying element11A and the output terminal116and between the output of the amplifying element11B and the output terminal116.

The output trans31is capable of converting a balanced signal into an unbalanced signal by combining balanced signals amplified in the amplifying elements11A and11B. That is, the output trans31is a balance-unbalance converter. Specifically, the output trans31is capable of combining an inverted signal and a non-inverted signal of a transmission signal of the communication band A.

The capacitor32is connected between the output of the amplifying element11A and the output of the amplifying element11B. Specifically, one end of the capacitor32is connected with the output of the amplifying element11A and one end of the coil31a. Further, the other end of the capacitor32is connected with the output of the amplifying element11B and the other end of the coil31a.

According to the circuit configuration of the power amplifier11, the amplifying elements11A and11B operate in inverted phases. At this time, current in a fundamental wave of the amplifying element11A and current in a fundamental wave of the amplifying element11B flow in inverted phases, that is, flow in opposite directions. Therefore, it becomes hard for current in the fundamental wave to flow toward ground wiring and power supply wiring which are arranged at substantially the same distance from the amplifying elements11A and11B. This can suppress unwanted current flow into the ground wiring and the power supply wiring, being able to suppress reduction of power gain which have been found in conventional power amplifiers. Also, a non-inverted signal and an inverted signal that are amplified in the amplifying elements11A and11B respectively are combined. Therefore, noise components that are similarly superimposed on both of the signals can be canceled and even-order harmonic wave components can be reduced.

The circuit configuration of the power amplifier11inFIG.2is an example and is not limited to this. For example, the power amplifier11does not have to include the amplifying element11C and the capacitor32. Further, when a balanced signal is inputted into the power amplifier11, the power amplifier11does not have to include the input trans33.

In addition, a trans is used for unbalance-balance conversion and balance-unbalance conversion in the present embodiment, but the present disclosure is not limited to this. Namely, an input converter and an output converter are not limited to the input trans33and the output trans31. For example, delay lines can be used as an input converter and an output converter.

Simultaneous use of transmission in the communication band A, transmission in the communication band B, and reception in the communication band C in the communication device5will now be described.FIG.3is a diagram illustrating signal flow in the communication device5according to the embodiment. Dashed arrows inFIG.3indicate signal flow.

InFIG.3, transmission in the communication band A, transmission in the communication band B, and reception in the communication band C are simultaneously used. That is,FIG.3illustrates a state of carrying out simultaneous transmission of a transmission signal of the communication band A, a transmission signal of the communication band B, and a reception signal of the communication band C.

In this example, all of the terminals512to514of the switch51are connected with the terminal511. Accordingly, a transmission signal of the communication band A is transmitted from the RFIC3through the high-frequency input terminal111, power amplifier11, filter61, switch51, and antenna connection terminal100in this order to the antenna2. Further, a transmission signal of the communication band B is transmitted from the RFIC3through the high-frequency input terminal112, power amplifier12, filter62, switch51, and antenna connection terminal100in this order to the antenna2. Further, a reception signal of the communication band C is transmitted from the antenna2through the antenna connection terminal100, switch51, filter63, low noise amplifier21, and high-frequency output terminal121in this order to the RFIC3.

At this time, in the switch51and/or the filters61to63, for example, IMD is generated between a second harmonic wave of the transmission signal of the communication band A and a fundamental wave of the transmission signal of the communication band B. A frequency fIMD of IMD is expressed as the following by using a frequency fA of a fundamental wave of the transmission signal of the communication band A and a frequency fB of the fundamental wave of the transmission signal of the communication band B.
fIMD=2fA−fB

As the frequency fA, an arbitrary frequency within the transmission band of the communication band A can be used. In a similar manner, as the frequency fB, an arbitrary frequency within the transmission band of the communication band B can be used. Thus, the frequency fIMD of IMD also varies within a frequency range defined depending on the transmission bands of the communication bands A and B.

If the frequency fIMD of IMD is included in the reception band of the communication band C, an unwanted wave of the IMD interferes a reception signal of the communication band C and reception sensitivity is accordingly degraded. In such circumstances, the high-frequency circuit1according to the present embodiment includes a differential amplifier as the power amplifier11for amplifying a transmission signal of the communication band A. This can suppress generation of a second harmonic wave of a transmission signal of the communication band A and reduce an unwanted wave of the IMD.

1.3 Specific Examples of Communication Bands A, B, and C

Specific examples of the communication bands A, B, and C will now be described. In the present embodiment, the communication bands A, B, and C satisfy the following conditions (1) and (2). (1) Transmission in the communication band A, transmission in the communication band B, and reception in the communication band C can be simultaneously used. (2) At least part of a frequency range of IMD, which is generated between a second harmonic wave of a transmission signal of the communication band A and a fundamental wave of a transmission signal of the communication band B, overlaps with at least part of the reception band of the communication band C.

Combinations shown in Table 1 are the conceivable specific examples of the communication bands A to C satisfying the conditions (1) and (2).

The combinations of communication bands shown in Table 1 be examples and the communication bands A to C be not limited to the above.

As described above, the high-frequency circuit1according to the present embodiment includes: the filter61that has a pass band including the transmission band of the communication band A; the filter62that has a pass band including the transmission band of the communication band B which is different from the communication band A; the filter63that has a pass band including the reception band of the communication band C; the power amplifier11that is connected with the filter61; and the power amplifier12that is connected with the filter62. Transmission in the communication band A, transmission in the communication band B, and reception in the communication band C can be simultaneously used. At least part of a frequency range of intermodulation distortion, which is generated between a second harmonic wave of a transmission signal of the communication band A and a fundamental wave of a transmission signal of the communication band B, overlaps with at least part of the reception band of the communication band C. The power amplifier11includes the amplifying elements11A and11B and the output trans including the coils31aand31b. One end of the coil31ais connected with the output of the amplifying element11A, the other end of the coil31ais connected with the output of the amplifying element11B, and one end of the coil31bis connected with the output terminal116of the power amplifier11.

According to this configuration, the power amplifier11is capable of individually amplifying balanced signals by the amplifying elements11A and11B and combining the amplified balanced signals at the output trans31so as to generate an unbalanced signal. Accordingly, second harmonic wave components contained in an unbalanced signal can be reduced and therefore, intermodulation distortion, which is generated between a second harmonic wave of a transmission signal of the communication band A and a fundamental wave of a transmission signal of the communication band B, can also be reduced. As a result, interference by an unwanted wave of the intermodulation distortion to a reception signal of the communication band C can be suppressed and degradation of reception sensitivity caused by the intermodulation distortion can be suppressed. Further, the output trans31is capable of performing impedance conversion in addition to balance-unbalance conversion and accordingly, impedance matching can be achieved between an output impedance of the power amplifier11and an input impedance of the filter61.

Further, for example, in the high-frequency circuit1according to the present embodiment, the power amplifier11may correspond to a high-power class, the power amplifier12may correspond to a non-high-power class, and the maximum output power of the high-power class may be larger than the maximum output power of the non-high-power class.

According to this configuration, generation of a second harmonic wave can be suppressed in the power amplifier11which is required to have greater output power. Thus, a second harmonic wave of a transmission signal of the communication band A can be effectively reduced and intermodulation distortion, which is generated between a second harmonic wave of a transmission signal of the communication band A and a fundamental wave of a transmission signal of the communication band B, can also be more effectively reduced.

Further, for example, in the high-frequency circuit1according to the present embodiment, the amplifying elements11A and11B may be capable of individually amplifying a balanced signal that is a transmission signal of the communication band A, and by combining the balanced signal amplified in the amplifying element11A and the balanced signal amplified in the amplifying element11B with each other, the output trans31may be capable of converting the balanced signals into an unbalanced signal.

According to this configuration, balanced signals can be individually amplified and the amplified balanced signals can be combined to generate an unbalanced signal.

Further, for example, in the high-frequency circuit1according to the present embodiment, the power amplifier12may be capable of amplifying a transmission signal of the communication band B as an unbalanced signal without necessarily conversion.

According to this configuration, a so-called non-differential amplifier can be used as the power amplifier12. In a non-differential amplifier, the number of amplifying elements can be reduced and elements for balance-unbalance conversion and the like can be omitted. Accordingly, the power amplifier12can be downsized compared to a differential amplifier, being able to contribute to downsizing of the high-frequency circuit1. Further, in the present embodiment, a second harmonic wave generated in the power amplifier12has little effect on intermodulation distortion included in the reception band of the communication band C described above. Accordingly, even when a differential amplifier is not used as the power amplifier12, degradation of reception sensitivity caused by intermodulation distortion can be suppressed with the use of a differential amplifier as the power amplifier11.

Further, for example, in the high-frequency circuit1according to the present embodiment, the power amplifier11may further include an input converter that is connected with the amplifying element11A and the amplifying element11B and is capable of converting a transmission signal of the first communication band from an unbalanced signal into the balanced signal.

According to this configuration, the power amplifier11is capable of converting an unbalanced signal into a balanced signal and therefore, the power amplifier11can receive a transmission signal of the communication band A from the RFIC3as the transmission signal is an unbalanced signal. Thus, a conventional high-frequency circuit can be replaced with the high-frequency circuit1according to the present embodiment.

Further, for example, in the high-frequency circuit1according to the present embodiment, the input converter may be the input trans33that includes the coil33aand the coil33b. One end of the coil31amay be connected with the input terminal115of the power amplifier11, one end of the coil33bmay be connected with the input of the amplifying element11A, and the other end of the coil33bmay be connected with the input of the amplifying element11B.

According to this configuration, a transformer can be used as an input converter. Thus, the input converter is capable of performing impedance conversion in addition to unbalance-balance conversion.

Further, for example, in the high-frequency circuit1according to the present embodiment, both of the communication band A and the communication band C may be a band 1 for LTE or 5GNR and the communication band B may be a band 3 for LTE or 5GNR. Further, for example, in the high-frequency circuit1according to the present embodiment, the communication band A may be the band 3 for LTE or 5GNR, the communication band B may be the band 1 for LTE or 5GNR, and the communication band C may be a band 32 for LTE or 5GNR. Further, for example, in the high-frequency circuit1according to the present embodiment, the communication band A may be a band 40 for LTE or 5GNR, the communication band B may be the band 1 for LTE or 5GNR, and the communication band C may be a band 41 for LTE or 5GNR. Further, for example, in the high-frequency circuit1according to the present embodiment, the communication band A may be the band 40 for LTE or 5GNR, the communication band B may be the band 1 for LTE or 5GNR, and the communication band C may be a band 7 for LTE or 5GNR. Further, for example, in the high-frequency circuit1according to the present embodiment, the communication band A may be the band 1 for LTE or 5GNR, the communication band B may be the band 7 for LTE or 5GNR, and the communication band C may be the band 32 for LTE or 5GNR.

The use of these communication bands as the communication bands A to C can effectively suppress degradation of reception sensitivity caused by intermodulation distortion.

Further, the communication device5according to the present embodiment includes the RFIC3that processes a high-frequency signal and the high-frequency circuit1that transmits the high-frequency signal between the RFIC3and the antenna2.

Accordingly, the same effects as those of the high-frequency circuit1can be realized in the communication device5.

Other Embodiments

The high-frequency circuit and communication device according to the present disclosure have been described above based on the embodiment. However, the high-frequency circuit and communication device according to the present disclosure are not limited to the above-described embodiment. The disclosure also includes modifications that can be obtained by making various changes, which a person skilled in the art can think of, to the above-described embodiment without necessarily departing from the scope of the present disclosure, and various devices incorporating the above-described high-frequency circuit and communication device.

For example, in the circuit configurations of the high-frequency circuit and communication device according to the above-described embodiment, another circuit element and wiring, for example, may be inserted between the paths connecting the circuit elements and signal paths disclosed in the drawings. For example, an impedance matching circuit may be inserted between the switch51and each of the filters61to63. This impedance matching circuit can be composed, for example, of an inductor and/or a capacitor.

Further, for example, each of the power amplifiers11and12and low noise amplifier21may be shared by a plurality of communication bands, in the circuit configurations of the high-frequency circuit and communication device according to the above-described embodiment. For example, the power amplifier11may be connected with a plurality of filters via a switch.

Furthermore, for example, when the communication bands A and C are identical communication bands, the filters61and63may be configured as a duplexer, in the circuit configuration of the high-frequency circuit according to the above-described embodiment.

Also, for example, the communication device according to the above-described embodiment may include a plurality of antennas. In this configuration, the filters61to63may be individually connected with different filters. Alternatively, two of the filters61to63may be connected with one antenna and the remaining one of the filters61to63may be connected with another antenna.

INDUSTRIAL APPLICABILITY

The present disclosure is widely applicable to communication devices, such as mobile phones, as a high-frequency circuit arranged in a front end portion.

REFERENCE SIGNS LIST