Radio-frequency circuit and communication device

A radio-frequency circuit includes a power amplifying circuit configured to amplify a first radio-frequency signal having a first channel bandwidth and a second radio-frequency signal having a second channel bandwidth greater than the first channel bandwidth. The power amplifying circuit is configured to amplify the first radio-frequency signal in an amplifying mode according to an average power tracking method, and to amplify the second radio-frequency signal in an amplifying mode according to an envelope tracking method.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority of Japanese Patent Application No. 2019-121735 filed on Jun. 28, 2019. The entire disclosure of the above-identified application, including the specification, drawings and claims is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a radio-frequency circuit and a communication device including the radio-frequency circuit.

BACKGROUND

Radio-frequency circuits that support multiband and multimode communication should transmit, with high quality, a plurality of radio-frequency signals having different communication band bandwidths and channel bandwidths.

Patent Literature (PTL) 1 discloses a circuit configuration of a power amplification module capable of switching between operation according to an envelope tracking method and operation according to an average power tracking method, according to the output power of a power amplifier. According to this paper, a small and low-cost amplifier module can be provided.

BRIEF SUMMARY

However, in the power amplifier module (a radio-frequency circuit) disclosed in PTL 1, there is the issue that power consumption of a power amplifying circuit becomes high when radio-frequency signals of a communication band having a wide bandwidth or radio-frequency signals having a wide channel bandwidth are amplified according to the average power tracking method.

In view of the above, the present disclosure provides a radio-frequency circuit and a communication device that reduce power consumption of a power amplifying circuit.

A radio-frequency circuit according to an aspect of the present disclosure includes a power amplifying circuit configured to amplify a first radio-frequency signal having a first channel bandwidth and a second radio-frequency signal having a second channel bandwidth greater than the first channel bandwidth, wherein the power amplifying circuit is configured to amplify the first radio-frequency signal in an amplifying mode according to an average power tracking method, and amplify the second radio-frequency signal in an amplifying mode according to an envelope tracking method.

The present disclosure can provide a radio-frequency circuit and a communication device that reduce power consumption of a power amplifying circuit.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings. It should be noted that each of the subsequently described exemplary embodiments shows a generic or a specific example. The numerical values, shapes, materials, elements, the arrangement and connection of the elements, and others indicated in the following exemplary embodiments are mere examples, and therefore are not intended to limit the present disclosure. Among the elements described in the following exemplary embodiments, elements not recited in any one of the independent claims are described as optional elements. In addition, the sizes of the elements and the ratio of the sizes illustrated in the drawings are not necessarily accurate.

EMBODIMENTS AND VARIATIONS

FIG.1is a circuit configuration diagram of radio-frequency circuit1and communication device6according to the embodiment. As illustrated in the figure, communication device6includes radio-frequency circuit1, antenna element21, amplification mode switching circuit3, RF signal processing circuit (RFIC)4, and baseband signal processing circuit (BBIC)5.

Power amplifying circuit10includes power amplifier11. Specifically, power amplifying circuit10includes a single power amplifier11. It should be noted that power amplifying circuit10may include two or more power amplifiers, or may include a circuit element other than a power amplifier. Power amplifier11is connected between input terminal130and filter circuit13.

As a first application example of radio-frequency1according to this embodiment, power amplifying circuit10amplifies radio-frequency signal Sig1(a first radio-frequency signal) having channel bandwidth BW1(a first channel bandwidth) and radio-frequency signal Sig2(a second radio-frequency signal) having channel bandwidth BW2(a second channel bandwidth) which is wider than channel bandwidth BW1.

Power amplifier11includes, for example, bipolar amplifier transistors having a base terminal, an emitter terminal, and a collector terminal. It should be noted that the amplifier transistors included in power amplifier11are not limited to a bipolar transistor, and may be a metal-oxide-semiconductor field-effect-transistor (MOSFET), for example.

A bias signal (a direct current bias voltage or a direct current bias current) is supplied to the base terminal and a direct current power supply voltage is supplied to the collector terminal of each of the amplifier transistors included in power amplifier11. Changing (the voltage or current of) the bias signals supplied to the base terminal of each of the amplifier transistors optimizes the operating point of the respective amplifier transistors.

Filter circuit13, which is an example of a first filter, is connected between power amplifier110and output terminal110, and allows the radio-frequency signal amplified by power amplifier11to pass with low loss. It should be noted that filter circuit13, input terminal130, and output terminal110are not necessarily essential elements of radio-frequency circuit1according to this embodiment.

Here, in the first application example of radio-frequency circuit1according to this embodiment, power amplifying circuit10amplifies radio-frequency signal Sig1according to the average power tracking (APT) method and amplifies radio-frequency signal Sig2according to the envelope tracking (ET) method.

FIGS.2A and2Billustrate schematic waveform diagrams for describing the APT mode and the ET mode. As illustrated inFIG.2B, the ET mode (i.e., an amplification mode according to the ET method) is a mode that tracks the power amplitude (an envelope) of the radio-frequency signal, and varies the bias signal (a direct current bias voltage or direct current bias current) to be supplied to (the base terminals of the amplifier transistors of) the power amplifier according to the envelope. In contrast, as illustrated inFIG.2A, the APT mode (i.e., an amplification mode according to the APT method) is a mode that follows the average power amplitude of a radio-frequency signal calculated on a predetermined period basis, and varies the bias signal (a direct current bias voltage or direct current bias current) to be supplied to (the base terminals of the amplifier transistors of) the power amplifier according to the average power amplitude.

FIG.3Ais a diagram illustrating an example of the distribution of a fourth generation mobile communication system (4G)-long term evolution (LTE) channel and a fifth generation mobile communication system (5G)-new radio (NR) channel which have different channel bandwidths. In the figure, Band 41 (the band: 2496 MHz to 2690 MHz) of 4G-LTE and n41 (the band: 2496 MHz to 2690 MHz) of 5G-NR which have the same frequency bands are written together.

As illustrated inFIG.3A, for example, a signal having a channel bandwidth as Band 41 is a radio-frequency signal used in 4G and has a channel bandwidth of 5 MHz, 10 MHz, 15 MHz, or 20 MHz. Furthermore, for example, a signal having a channel bandwidth as n41 is a radio-frequency signal used in 5G and has a channel bandwidth of 10 MHz, 15 MHz, 20 MHz, 30 MHz, 40 MHz, 50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, or 100 MHz.

In the first application example of radio-frequency circuit1according to this embodiment inFIG.1, for example, the channel allocation illustrated inFIG.3Ais applied. For example, a signal having channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 41) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(50 MHz) of 5G-NR (n41) is applied as radio-frequency signal Sig2. In this case, channel bandwidth BW2of 5G-NR (n41) is wider than channel bandwidth BW1of 4G-LTE (Band 41).

It should be noted that radio-frequency signals Sig1and Sig2are not limited to the above-described channel allocation.

Table 1 indicates examples of channel bandwidths and band bandwidths (i.e., communication band bandwidths) of 4G-LTE communication bands and 5G-NR communication bands.

It should be noted that aside from the combinations given in Table 1, the combinations of radio-frequency signal Sig1and radio-frequency signal Sig2maybe the combinations described below.

In the first application example of radio-frequency circuit1according to this embodiment inFIG.1, for example, the channel allocation indicated in Table 1 may be applied. For example, a signal having channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 25-Tx) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(50 MHz) of 5G-NR (n41) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal having channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 5-Tx) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(50 MHz) of 5G-NR (n78) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal having channel bandwidth BW1(10 MHZ) of 5G-NR (Band n5-Tx) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(20 MHz) of 4G-LTE (B3-Tx) is applied as radio-frequency signal Sig2.

It should be noted that a signal of a wireless local area network (WLAN) of IEEE802.11 may be applied as radio-frequency signal Sig1or radio-frequency signal Sig2, and, for example, Wi-Fi 2.4 GHz band, Wi-Fi (5.15 GHz to 7.125 GHz), or WiGig is applied, for example. Moreover, the modulated signal of WLAN is the same as that of 5G-NR.

Specifically, radio-frequency signal Sig1may be a signal used in 4G and radio-frequency signal Sig2may be a signal of WLAN. Furthermore, in this case, the peak-to-average power ratio (PAPR) of radio-frequency signal Sig2may be larger than the PAPR of radio-frequency signal Sig1. When radio-frequency signal Sig1is a signal used in 4G and radio-frequency signal Sig2is a signal of WLAN, radio-frequency signal Sig1is a signal of a communication band given in Table 1 or a signal of any one of Band 28, 20, 26, 8, 3, 66, 39, 2, 1, or 40 (bands: 2300 MHz to 2400 MHz).

Furthermore, radio-frequency signal Sig1may be a signal of WLAN, and radio-frequency signal Sig2may be a signal used in 5G. When radio-frequency signal Sig1is a signal of WLAN and radio-frequency signal Sig2is a signal used in 5G, the signal of WLAN is a signal within the 5.15 GHz to 7.125 GHz band, and the signal used in 5G is a signal within the 5.15 GHz to 7.125 GHz band or a signal of any one of n41, n77, n78, and n79.

In a radio-frequency circuit that includes a power amplifier, the power consumption of the power amplifier occupies a large portion of the power consumption of the radio-frequency circuit, and thus, in order to reduce power consumption, improving the efficiency of the power amplifier is a challenge. The ET method is given as a technique of improving the efficiency of the power amplifier. In modulation methods such as orthogonal frequency division multiplexing (OFDM) used in wireless communication, the ratio of peak power to average power (i.e., peak-to-average power ratio (PAPR)) of an input signal of a power amplifier becomes large. In amplifying and transmitting such a modulated signal, for the input signal during peak power, a bias voltage is applied to the amplifier transistor so that the amplifier transistor operates in the compression region. In other words, because the bias voltage becomes excessive during average power, varying the bias voltage according to the input modulated signal of the power amplifier (ET mode) enables the power consumption of the power amplifier to be reduced. In the case of the ET mode, however, since the power amplifier is made to operate in the compression region, signal distortion is generated. In contrast, the APT mode, though inferior to the ET mode in terms of reducing power consumption, can reduce the generation of signal distortion compared to the ET mode.

On the other hand, as the frequency bandwidth of the radio-frequency signal to be amplified by the power amplifier becomes wider, the frequency for which the power amplifier has to perform amplification becomes a wider band, and thus the power consumption of the power amplifier becomes high. In particular, the wider the channel bandwidth of the radio-frequency signal to be amplified by the power amplifier is, the higher the power consumption of the power amplifier becomes.

Since the change in amplitude to be tracked according to the ET mode increases as the PAPR is larger, signal distortion increases. Since PAPR is the amplitude fluctuation when a composite signal of respective subcarriers that have undergone multi-value modulation is viewed over the temporal axis, the PAPR of the composite signal tends to be larger as the multi-value (the number of symbols) and number of carriers (the number of different frequencies) is greater. As one example, a diagram comparing the magnitude of the PAPRs of modulated signals defined in 3GPP TS 38.101-1 is provided.

FIG.3Cis a graph illustrating a relationship between a primary modulation method and a secondary modulation method, and PAPR. In the figure, the horizontal axis denotes the modulation method and the vertical axis denotes the PAPR. Primary modulation methods include, for example, phase-shift keying (PSK), amplitude-shift keying (ASK), frequency-shift keying (FSK), or quadrature amplitude modulation: QAM), and the like. InFIG.3C, quadrature phase-shift keying (QPSK) and 256-QAM are given as examples of primary modulation methods. PAPR has strong dependence on the secondary modulation method (SC-FDMA, DFT-s-OFDM, and CP-OFDM), and a PAPR increases in the order of SC-FDMA, DFT-s-OFDM, and CP-OFDM. In other words, the PAPR of a 5G-NR signal is larger than the PAPR of an LTE signal. Accordingly, a 5G-NR signal is more prone to amplifier output waveform distortion than an LTE signal.

It should be noted that single-carrier frequency-division multiplexing (SC-FDM) is to be used for a secondary modulation method (uplink) of the LTE signal. Moreover, there are also cases where the term SC-FDM means single-carrier frequency-division multiple access (SC-FDMA) which is multiple connection in which SC-FDM is applied. In the present disclosure, SC-FDMA is used in place of SC-FDM.

Furthermore, discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-s-OFDM) or cyclic prefix orthogonal frequency-division multiplexing (CP-OFDM) is used for the secondary modulation method of the 5G-NR signal. A WLAN signal is a signal that is transmitted according to the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standard. Orthogonal frequency-division multiplexing (OFDM) is used for the secondary modulation method of the WLAN signal. It should be noted that there are also cases where DFT-s-OFDM, CP-OFDM, and OFDM may mean orthogonal frequency division multiple access (OFDMA) which is multiple connection in which each of DFT-s-OFDM, CP-OFDM, and OFDM is applied.

In view of the above, according to the first application example of this embodiment, radio-frequency signal Sig1having relatively narrow channel bandwidth BW1is amplified in the APT mode and radio-frequency signal Sig2having a relatively wide channel bandwidth BW2is amplified in the ET mode. According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1of 4G-LTE (e.g., Band 41) for which power consumption is low and the ET mode enables the reduction of power consumption in the amplification of radio-frequency signal Sig2of 5G-NR (e.g., n41) for which power consumption is high. Therefore, radio-frequency circuit1and communication device6that reduce the power consumption of power amplifying circuit10can be provided.

It should be noted that when the 5G-NR signal is a modulated signal having a larger PAPR than the 4G-LTE signal, the distortion reduction effect increases. The modulation method of the modulated signal is 256-QAM or CP-OFDM, for example.

It should be noted that when the WLAN signal is a modulated signal having a larger PAPR than the 4G-LTE signal or the 5G-NR, the distortion reduction effect increases. The modulated signal is of 256-QAM or CP-OFDM, for example.

It should be noted that in radio-frequency circuit1according to this embodiment inFIG.1, power amplifier11amplifies radio-frequency signal Sig1and radio-frequency signal Sig2by time division. According to this configuration, the power consumption when amplifying radio-frequency signal Sig2which has a wide channel bandwidth can be reduced while amplifying two radio-frequency signals having different channel bandwidths by time division. It should be noted that, when power amplifying circuit10includes two or more power amplifiers, radio-frequency signal Sig1and radio-frequency signal Sig2may be simultaneously amplified by the two or more power amplifiers, and the two radio-frequency signals that have been amplified may be simultaneously transmitted from radio-frequency circuit1. The configuration for this simultaneous amplification and simultaneous transmission will be described in detail in Variations 1 and 2 of the embodiment inFIG.1.

Hereinafter, elements included in communication device6other than radio-frequency circuit1will be described.

Antenna element21is connected to output terminal110of radio-frequency circuit1, transmits the radio-frequency signal amplified by power amplifying circuit10, and receives radio-frequency signals transmitted from another communication device (base station, and the like).

RFIC4is an RF signal processing circuit that processes radio-frequency signals. Specifically, RFIC4performs, by upconversion, etc., signal processing on transmission signals input from BBIC5, and outputs the radio-frequency transmission signals generated by the signal processing to radio-frequency circuit1. Furthermore, RFIC4includes a controller (e.g., a processor) that outputs a control signal for controlling whether power amplifying circuit10operates in the ET mode or the APT mode, based on information on which of radio-frequency signal Sig1or Sig2is to be output to radio-frequency circuit1.

BBIC5is a circuit that performs signal processing using an intermediate frequency band having a lower frequency than a radio-frequency signals propagating in radio-frequency circuit1. The signal processed by BBIC5is, for example, used as image signals for image display or as a sound signal for conversation via a speaker.

Amplification mode switching circuit3is disposed between the controller of RFIC4and power amplifying circuit10. Amplification mode switching circuit3switches between supplying bias signal b1(a first bias signal) corresponding to the APT mode and supplying bias signal b2(a second bias signal) corresponding to the ET mode, to power amplifier11, based on control signal s0output from the controller of RFIC4.

According to the above-described configuration of communication device6, output power information of power amplifier11is received by RFIC4, and the controller of RFIC4determines the amplification mode based on the output power information. The controller outputs control signal s0corresponding to the determined amplification mode to amplification mode switching circuit3. Amplification mode switching circuit3switches the supplying bias signals (b1or b2) for the APT mode or the ET mode to radio-frequency circuit1, based on aforementioned control signal s0. Therefore, power consumption can be reduced using the simplified circuit configuration of communication device6.

It should be noted that in communication device6according to this embodiment inFIG.1, antenna element21and BBIC5are not necessarily essential elements.

Furthermore, the controller that outputs the control signals for controlling whether power amplifier11is to operate in the ET mode or the APT mode need not to be included in RFIC4, and may be included in BBIC5, or may be included in another element of communication device6other than RFIC4and BBIC5.

Furthermore, in radio-frequency circuit1and communication device6according to this embodiment, when a value indicating the output power of the radio-frequency signal output from power amplifying circuit10is greater than a threshold power, radio-frequency signal Sig1may be amplified in an amplification mode according to the APT method and radio-frequency signal Sig2may be amplified in an amplification mode according to the ET method.

According to this configuration, in the high output region in which the power consumption of power amplifying circuit10outputting the radio-frequency signal becomes high, radio-frequency signal Sig2which has a wider channel bandwidth than radio-frequency signal Sig1is amplified in the ET mode, and thus the power consumption of power amplifying circuit10can be effectively reduced. It should be noted that, the permitted value of the radio-frequency component of the radio-frequency signal that is output from power amplifier11or the permitted value of the intermodulation distortion generated by the radio-frequency signal that is output from power amplifier11and the radio-frequency signal that is output from another power amplifier are given as examples of the threshold power. Moreover, when the value indicating the output power of the radio-frequency signal output from power amplifying circuit10is less than or equal to the threshold power, power amplifying circuit10may, for example, amplify both radio-frequency signals Sig1and Sig2in the amplification mode according to the APT method.

It should be noted that although one of radio-frequency signals Sig1and Sig2is a signal used in 4G and the other of radio-frequency signals Sig1and Sig2is a signal used in 5G in radio-frequency circuit1according to this embodiment, they are not limited to such signals. In radio-frequency circuit1according to this embodiment, radio-frequency signal Sig1may be a signal used in 4G and radio-frequency signal Sig2may also be a signal used in 4G.

According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1of 4G-LTE which has a wide channel bandwidth, and the ET mode enables the reduction of power consumption in the amplification of radio-frequency signal Sig2of 4G-LTE which has a wide channel bandwidth. Therefore, in radio-frequency circuit1and communication device6that transfer 4G-LTE radio-frequency signals, power consumption can be reduced.

Furthermore, in radio-frequency circuit1according to this embodiment, radio-frequency signal Sig1may be a signal used in 5G and radio-frequency signal Sig2may also be a signal used in 5G.

According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1of 5G-NR which has a narrow channel bandwidth, and the ET mode enables the reduction of power consumption in the amplification of radio-frequency signal Sig2of 5G-NR which has a narrow channel bandwidth. Therefore, in radio-frequency circuit1and communication device6that transfer 5G-NR radio-frequency signals, power consumption can be reduced.

It should be noted that, in communication device6according to this embodiment inFIG.1, the antenna that transmits and receives radio-frequency signal Sig1and the antenna that transmits and receives radio-frequency signal Sig2may be different. In other words, communication device6may include a first antenna element and a second antenna element in place of antenna element21. In this case, for example, a single-pole double-throw (SPDT) switch is disposed between filter circuit13and the first and second antenna elements. The common terminal of the switch is connected to filter circuit13, the first selection terminal of the switch is connected to the first antenna element, and the second selection terminal of the switch is connected to the second antenna element. The switch switches between making a conduction and making non-conduction between the common terminal and the first antenna element and conduction and non-conduction between the common terminal and the second antenna element. According to this configuration, the isolation between radio-frequency signal Sig1and radio-frequency signal Sig2can be improved while amplifying radio-frequency signal Sig1and radio-frequency signal Sig2using a single power amplifier11.

It should be noted that, as a second application example of radio-frequency circuit1according to this embodiment inFIG.1, power amplifying circuit10may be a transmission amplifying circuit capable of amplifying radio-frequency signal Sig1(a first radio-frequency signal) of a first communication band having band bandwidth BW1and radio-frequency signal Sig2(a second radio-frequency signal) of a second communication band having a band bandwidth BW2which is greater than band bandwidth BW1. Specifically, instead of switching amplification modes according to radio-frequency signals Sig1and Sig2having channel bandwidths that are in a wideness/narrowness relation, power amplifying circuit10may switch amplification modes according to radio-frequency signals Sig1and Sig2having communication band frequency bands that are in a wideness/narrowness relation.

At this time, in radio-frequency circuit1according to this embodiment inFIG.1, power amplifying circuit10amplifies radio-frequency signal Sig1in the amplification mode according to the APT method, and amplifies radio-frequency signal Sig2in the amplification mode according to the ET method.

FIG.3Bis a diagram indicating an example of the distribution of a 4G-LTE communication band and a 5G-NR communication band having different band bandwidths (i.e., communication band bandwidths). In the figure, Band 25-Tx (the transmission band: 1850 MHz to 1915 MHz) of 4G-LTE and n41 (the band: 2496 MHz to 2690 MHz) of 5G-NR which have different frequency bands are written together.

As illustrated inFIG.3B, for example, the radio-frequency signal of Band 25-Tx which has a band bandwidth of 65 MHz is a radio-frequency signal used in 4G. Furthermore, the radio-frequency signal of n41 which has a band bandwidth of 194 MHz is a radio-frequency signal used in 5G.

In the second application example of radio-frequency1according to this embodiment inFIG.1, for example, the communication bands illustrated inFIG.3Bare applied. For example, a signal of 4G-LTE (Band 25-Tx) having band bandwidth BW1of 65 MHz is applied as radio-frequency signal Sig1, and a signal of 5G-NR (n41) having band bandwidth BW2of 194 MHz as radio-frequency signal Sig2. In other words, the band bandwidth of 5G-NR (n41) is greater than the band bandwidth of 4G-LTE (Band 25-Tx). Since the channel bandwidth tends to be wider with a wider band bandwidth, in the case of the second application example, the channel bandwidth of 5G-NR (n41) tends to be wider than the channel bandwidth of 4G-LTE (Band 25-Tx), and thus the power consumption of power amplifying circuit10becomes higher for the radio-frequency signal of 5G-NR (n41).

It should be noted that radio-frequency signals Sig1and Sig2are not limited to the above-described communication band allocation.

In the second application example of radio-frequency circuit1according to this embodiment inFIG.1, for example, the communication band allocation indicated in Table 1 may be applied. For example, a signal of 4G-LTE (Band 25-Tx) is applied as radio-frequency signal Sig1, and a signal of 5G-NR (n41) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal of 4G-LTE (Band 5-Tx) is applied as radio-frequency signal Sig1, and a signal of 5G-NR (n78) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal of 5G-NR (n5-Tx) is applied as radio-frequency signal Sig1, and a signal of 4G-LTE (B3-Tx) is applied as radio-frequency signal Sig2.

As the frequency bandwidth of the radio-frequency signal to be amplified by the power amplifier becomes wider, the frequency for which the power amplifier has to perform amplification becomes a wider band, and thus the signal distortion component of the amplified radio-frequency signal becomes bigger. In particular, the wider the channel bandwidth of the radio-frequency signal to be amplified by the power amplifier is, the bigger the signal distortion component of the amplified radio-frequency signal becomes. Whereas, although signal distortion is generated in the ET mode, the APT mode, though inferior to the ET mode in terms of reducing power consumption, can reduce the generation of signal distortion compared to the ET mode.

In contrast, according to the second application example of this embodiment, radio-frequency signal Sig1having relatively narrow channel bandwidth BW1(the channel bandwidth tends to be narrow) is amplified in the APT mode and radio-frequency signal Sig2having relatively wide channel bandwidth BW2(the channel bandwidth tends to be wide) is amplified in the ET mode. According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1of 4G-LTE (Band 25-Tx) for which power consumption tends to be low and the ET mode enables the reduction of power consumption in the amplification of radio-frequency signal Sig2of 5G-NR (n41) for which power consumption tends to become high. Therefore, radio-frequency circuit1and communication device6that reduce the power consumption of power amplifying circuit10can be provided.

It should be noted that in the second application example of radio-frequency circuit1according to this embodiment, the pass band of filter circuit13includes bandwidth BW1of the first communication band and bandwidth BW2of the second communication band.

According to this configuration, the power consumption of power amplifying circuit10when amplifying a radio-frequency signal of a communication band having a wide bandwidth can be reduced while amplifying two radio-frequency signals having different communication bands by time division.

It should be noted that the elements included in communication device6other than radio-frequency circuit1in the second application example are the same in the first application example, and thus their description is omitted.

3. Configuration of Radio-Frequency Circuit1A and Communication Device6A According to Variation 1 (First Application Example)

FIG.4is a circuit configuration diagram of radio-frequency circuit1A and communication device6A according to Variation 1 of the embodiment. As illustrated in the figure, communication device6A includes radio-frequency circuit1A, antenna circuit2, amplification mode switching circuit3A, power supply7, RFIC4, and BBIC5. Compared to communication device6according to the embodiment inFIG.1, communication device6A according to this Variation 1 is different in the configuration of radio-frequency circuit1A, antenna circuit2, and amplification mode switching circuit3A, and in the addition of power supply7. Hereinafter, the description of communication device6A according to this variation will omit the elements that are the same as in communication device6according to the embodiment inFIG.1and will focus on those elements that are different.

Power amplifying circuit10includes power amplifiers11and12. Power amplifier11, which is an example of a first power amplifier, is connected between input terminal130and filter circuit13. Power amplifier12, which is an example of a second power amplifier, is connected between input terminal140and filter circuit14.

As a first application example of radio-frequency1A according to this Variation 1, power amplifying circuit10amplifies radio-frequency signal Sig1(a first radio-frequency signal) having channel bandwidth BW1(a first channel bandwidth) and radio-frequency signal Sig2(a second radio-frequency signal) having channel bandwidth BW2(a second channel bandwidth) which is wider than channel bandwidth BW1.

Power amplifier11and12each include, for example, bipolar amplifier transistors each having a base terminal, an emitter terminal, and a collector terminal. It should be noted that the amplifier transistors included in power amplifiers11and12are not limited to bipolar transistors, and may be MOSFETs, and the like, for example.

A bias signal (a direct current bias voltage or a direct current bias current) is supplied to the base terminal and a direct current power supply voltage is supplied to the collector terminal of each of the amplifier transistors included in power amplifiers11and12. Changing (the voltage or current of) the bias signal supplied to the base terminal of each of the amplifier transistors optimizes the operating point of the respective amplifier transistors.

Filter circuit13, which is an example of a first filter, is connected between the output terminal of power amplifier11and output terminal110, and allows the radio-frequency signal amplified by power amplifier11to pass with low loss. Filter circuit14, which is an example of a second filter, is connected between the output terminal of power amplifier12and output terminal120, and allows the radio-frequency signal amplified by power amplifier12to pass with low loss.

It should be noted that power amplifiers11and12may be integrated in a single chip. Furthermore, power amplifiers11and12and filter circuits13and14may be mounted on a single mounting board. According to this configuration, radio-frequency circuit1A can be miniaturized.

It should be noted that filter circuits13and14, input terminals130and140, and output terminals110and120are not necessarily essential elements of radio-frequency circuit1A according to this variation.

Here, in the first application example of radio-frequency circuit1A according to this Variation 1, power amplifying circuit10amplifies radio-frequency signal Sig1in the amplification mode according to the APT method, and amplifies radio-frequency signal Sig2in the amplification mode according to the ET method.

For example, power amplifier11amplifies radio-frequency signal Sig1, and power amplifier12amplifies radio-frequency signal Sig2. It should be noted that radio-frequency circuit1A can simultaneously amplify radio-frequency signal Sig1and radio-frequency signal Sig2.

According to the first application example of radio-frequency circuit1A according to this Variation 1, power amplifier11can amplify radio-frequency signal Sig1having a relatively narrow channel bandwidth in the APT mode, and power amplifier12can amplify radio-frequency signal Sig2having a relatively wide channel bandwidth in the ET mode. According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1for which power consumption is low, and the ET mode enables the reduction of power consumption of power amplifying circuit10in the amplification of radio-frequency signal Sig2for which power consumption is high. Therefore, radio-frequency circuit1A and communication device6A that reduce the power consumption of power amplifying circuit10while simultaneously amplifying two radio-frequency signals having different channel bandwidths can be provided.

In the first application example of radio-frequency1A according to this variation, for example, the channel allocation illustrated inFIG.3Ais applied. For example, a signal having channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 41) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(50 MHz) of 5G-NR (n41) is applied as radio-frequency signal Sig2. In this case, channel bandwidth BW2(50 MHz) of 5G-NR (n41) is wider than channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 41).

It should be noted that radio-frequency signals Sig1and Sig2are not limited to the above-described channel allocation.

In the first application example of radio-frequency circuit1A according to this Variation 1, for example, the channel allocation indicated in Table 1 may be applied. For example, a signal having channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 25-Tx) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(50 MHz) of 5G-NR (n41) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal having channel bandwidth BW1(10 MHZ) of 4G-LTE (Band 5-Tx) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(50 MHz) of 5G-NR (n78) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal having channel bandwidth BW1(10 MHZ) of 5G-NR (Band n5-Tx) is applied as radio-frequency signal Sig1, and a signal having channel bandwidth BW2(20 MHz) of 4G-LTE (B3-Tx) is applied as radio-frequency signal Sig2.

As the frequency bandwidth of the radio-frequency signal to be amplified by the power amplifier becomes wider, the frequency for which the power amplifier has to perform amplification becomes a wider band, and thus the signal distortion component of the amplified radio-frequency signal becomes bigger. In particular, the wider the channel bandwidth of the radio-frequency signal to be amplified by the power amplifier is, the bigger the signal distortion component of the amplified radio-frequency signal becomes. Whereas, although signal distortion is generated in the ET mode, the APT mode, though inferior to the ET mode in terms of reducing power consumption, can reduce the generation of signal distortion compared to the ET mode.

According to the first application example of this Variation 1, power amplifier11to which radio-frequency signal Sig1is input is configured to amplify in the APT mode, and power amplifier12to which radio-frequency signal Sig2is input is configured to amplify in the ET mode. According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1of 4G-LTE (Band 41) for which power consumption is low and the ET mode enables the reduction of power consumption in the amplification of radio-frequency signal Sig2of 5G-NR (n41) for which power consumption is high. Therefore, radio-frequency circuit1A and communication device6A that reduce the power consumption of power amplifying circuit10can be provided.

It should be noted that in radio-frequency circuit1A according to this Variation 1, the amplification of radio-frequency signal Sig1by power amplifier11and the amplification of radio-frequency signal Sig2by power amplifier12can be simultaneously executed. According to this configuration, the power consumption of power amplifying circuit10when amplifying of radio-frequency signal Sig2which has a wide channel bandwidth can be reduced while simultaneously amplifying two radio-frequency signals having different channel bandwidths.

Furthermore, in this variation, power amplifier11amplifies radio-frequency signal Sig1and power amplifier12amplifies radio-frequency signal Sig2, but are not limited to this. In radio-frequency circuit1A, power amplifier11may amplify radio-frequency signal Sig2and power amplifier12may amplify radio-frequency signal Sig1, or each of power amplifiers11and12may be capable of amplifying either radio-frequency signal Sig1or Sig2. Specifically, when power amplifier11amplifies one of radio-frequency signals Sig1and Sig2, power amplifier12may amplify the other of radio-frequency signals Sig1and Sig2. For this reason, the amplification of radio-frequency signal Sig2by power amplifier11and the amplification of radio-frequency signal Sig1by power amplifier12can be simultaneously executed.

The correspondence relation between power amplifiers11and12and radio-frequency signals Sig1and Sig2may be determined by RFIC4.

Hereinafter, elements included in communication device6A other than radio-frequency circuit1A will be described.

Antenna circuit2includes antenna elements22and23. Antenna element22is connected to output terminal110of radio-frequency circuit1A, transmits the radio-frequency signal amplified by power amplifier11, and receives a radio-frequency signal transmitted from another communication device (a base station, and the like). Antenna element23is connected to output terminal120of radio-frequency circuit1A, transmits the radio-frequency signal amplified by power amplifier12, and receives a radio-frequency signal transmitted from another communication device (a base station, and the like). By transmitting the radio-frequency signal output from power amplifier11and the radio-frequency signal output from power amplifier12from different antenna elements, two radio-frequency signals having different channel bandwidths can be transmitted or received with high isolation.

RFIC4is an RF signal processing circuit that processes a radio-frequency signal. Specifically, RFIC4performs, by upconversion, etc., signal processing on a transmission signal input from BBIC5, and outputs the radio-frequency transmission signal generated by the signal processing to radio-frequency circuit1A.

BBIC5is a circuit that performs signal processing using an intermediate frequency band having a lower frequency than the radio-frequency signal propagating in radio-frequency circuit1A. The signal processed by BBIC5is, for example, used as an image signal for image display or as a sound signal for conversation via a speaker.

Next, a specific configuration example of amplification mode switching circuit3A included in communication device6A will be described. Amplification mode switching circuit3A is disposed between the controller of RFIC4and power amplifiers11and12. Amplification mode switching circuit3A includes switches31and32, ET power supply circuits33and35, and APT power supply circuits34and36.

ET power supply circuit33is a bias circuit that is connected to power supply7and applies ET mode bias signal b2to one of the selection terminals of switch31based on control signal s03that is output by the controller of RFIC4. ET power supply circuit35is a bias circuit that is connected to power supply7and applies ET mode bias signal b2to one of the selection terminals of switch32based on control signal s05that is output by the controller of RFIC4.

APT power supply circuit34is a bias circuit that is connected to power supply7and applies APT mode bias signal b1to the other of the selection terminals of switch31based on control signal s04that is output by the controller of RFIC4. APT power supply circuit36is a bias circuit that is connected to power supply7and applies APT mode bias signal b1to the other of the selection terminals of switch32based on control signal s06that is output by the controller of RFIC4.

Switch31is a SPDT switch that includes one common terminal and two selection terminals; the common terminal is connected to power amplifier11, the one of the selection terminals is connected to ET power supply circuit33, and the other of the selection terminals is connected to APT power supply circuit34.

Switch32is a SPDT switch that includes one common terminal and two selection terminals; the common terminal is connected to power amplifier12, the one of the selection terminals is connected to ET power supply circuit35, and the other of the selection terminals is connected to APT power supply circuit36.

It should be noted that ET power supply circuits33and35need not to be separate power supply circuits, and may be a single power supply circuit. In this case, the aforementioned single power supply circuit has a circuit configuration that enables the distribution of ET mode bias signal b2to switches31and32. Furthermore, APT power supply circuits34and36need not to be separate power supply circuits, and may be a single power supply circuit. In this case, the aforementioned single power supply circuit has a circuit configuration that allows distribution of APT mode bias signal b1to switches31and32.

Moreover, ET power supply circuit33and APT power supply circuit34need not to be separate power supply circuits, and may be a single power supply circuit. In this case, switch31becomes unnecessary, and the aforementioned single power supply circuit has a circuit configuration that enables application of APT mode bias signal b1and ET mode bias signal b2to power amplifier11by time division. Moreover, ET power supply circuit35and APT power supply circuit36need not to be separate power supply circuits, and may be a single power supply circuit. In this case, switch32becomes unnecessary, and the aforementioned single power supply circuit has a circuit configuration that enables application of ET mode bias signal b2and APT mode bias signal b1to power amplifier12by time division.

Furthermore, power supply7is for generating the bias signals output by ET power supply circuits33and35and APT power supply circuits34and36. Power supply7need not to be included in communication device6A and may be provided outside thereof.

According to the above-described configuration, amplification mode switching circuit3A switches between supplying bias signal b1(a first bias signal) corresponding to the APT method and supplying bias signal b2(a second bias signal) corresponding to the ET method, to power amplifier11, based on control signals s03and s04output from the controller of RFIC4. Furthermore, amplification mode switching circuit3A switches between supplying bias signal b1(a first bias signal) corresponding to the APT method and supplying bias signal b2(a second bias signal) corresponding to the ET method, to power amplifier12, based on control signals s05and s06output from the controller of RFIC4.

RFIC4includes a controller (e.g., a processor) that outputs a control signal for controlling whether power amplifiers11and12operate in the ET mode or the APT mode, based on information on which of radio-frequency signal Sig1or Sig2is to be output to radio-frequency circuit1A. The controller of RFIC4determines, based on information (for example, a communication band or channel information) of a radio-frequency signal sent from a mobile system base station, the radio frequency signals to be output to input terminals130and140of radio-frequency circuit1A, and outputs the radio-frequency signals.

It should be noted that in radio-frequency circuit1A and communication device6A according to this Variation 1, power amplifiers11and12may amplify radio-frequency signal Sig1according to the APT method and amplify radio-frequency signal Sig2according to the ET method, when the value indicating the output power of the radio-frequency signal output from power amplifier11or12is greater than the threshold power.

In this case, RFIC4obtains a power value corresponding to the output power of power amplifier11by measuring a power using a coupler disposed in a path from the output terminal of power amplifier11to antenna element22. Furthermore, the controller of RFIC4, for example, obtains the power value corresponding to the output power of power amplifier12by measuring a power using a coupler disposed in a path from the output terminal of power amplifier12to antenna element23. Specifically, by obtaining the measurement results for the output power of power amplifiers11and12, the controller causes radio-frequency signal Sig1to be amplified according to the APT method and radio-frequency signal Sig2to be amplified according to the ET method, when the values indicating the output power of power amplifiers11and12are greater than the threshold power.

It should be noted that the way in which the controller of RFIC4obtains the power values corresponding to the output power of power amplifiers11and12may be by measurement using a power-measuring device other than a coupler. Furthermore, the controller of RFIC4may obtain, as the value indicating the output power of power amplifiers11and12, a required power sent from a mobile system base station which is the output power required from a radio-frequency transmission signal to be transmitted from communication device6A. In this manner, in the case of predicting the output power of power amplifiers11and12based on the required power sent from a mobile system base station, the controller causes radio-frequency signal Sig1to be amplified in the amplification mode according to the APT method and radio-frequency signal Sig2to be amplified in the amplification mode according to the ET method, when the values indicating the output power of power amplifiers11and12are greater than the threshold power.

According to the above-described configuration of communication device6A, the signal distortion of the amplified radio-frequency signals can be reduced using a simplified circuit configuration.

It should be noted that, in the case of the ET mode, as the tracking property of the bias voltage for an input modulated signal becomes higher, the distortion characteristics of the output signal tends to deteriorate. In contrast, in the case of the APT mode, reduction of power consumption is inferior to the ET mode but the generation of signal distortion can be reduced as compared to the ET mode.

ET power supply circuits33and35change the ET power supply voltage to correspond with the power amplitude of radio-frequency signal Sig2to be input to power amplifying circuit10(or to be output from power amplifying circuit10). According to this change of the ET power supply voltage, bias signal b2(bias voltage) applied to power amplifying circuit10varies by a second tracking degree relative to the power amplitude of radio-frequency signal Sig2, with a predetermined delay time.

Furthermore, APT power supply circuits34and36change the APT power supply voltage to conform with the power amplitude of radio-frequency signal Sig2to be input to power amplifying circuit10(or to be output from power amplifying circuit10). According to this change of the APT power supply voltage, bias signal b1(bias voltage) applied to power amplifying circuit10varies by a first tracking degree relative to the power amplitude of radio-frequency signal Sig1, with a predetermined delay time.

Since radio-frequency signal Sig2has a wide channel bandwidth compared to radio-frequency signal Sig1, the amplitude change period indicated by the channel bandwidth reciprocal (1/BW) is short. Furthermore, radio-frequency signal Sig2has a large PAPR as compared to radio-frequency signal Sig1.

For this reason, in communication device6A according to this Variation 1, the second tracking degree of bias signal b2may be higher than the first tracking degree of bias signal b1.

According to this configuration, when radio-frequency signal Sig2having a relatively wide channel bandwidth is to be input to power amplifying circuit10, bias signal b2having high tracking property is applied to power amplifying circuit10, and when radio-frequency signal Sig1having a relatively narrow channel bandwidth is to be input to power amplifying circuit10, bias signal b1having low tracking property is applied to power amplifying circuit10. In other words, the bias signal is optimized according to the channel bandwidth of the radio-frequency signal to be input. For this reason, even when the channel bandwidths of the radio-frequency signals to be input are different, signal distortion can be reduced as compared to when the same bias signal b2is applied. Furthermore, even when the channel bandwidths of the radio-frequency signals to be input are different, power consumption can be reduced compared to when the same bias signal b1is applied. According to this configuration, a plurality of radio-frequency signals having different channel bandwidths can be amplified by power amplifying circuit10while ensuring high amplification performance and low power consumption.

It should be noted that the tracking property (e.g., a tracking performance) of bias voltage relative to the input power amplitude is the responsiveness of a bias voltage to the change in the power amplitude of the radio-frequency signal input to power amplifying circuit10(or output from power amplifying circuit10), and is equivalent to the transition time (a rise time or a fall time) during the step response of the bias voltage, for example. Specifically, a high tracking property means that responsiveness is high and a transition time is short.

Specifically, in radio-frequency circuit1A and communication device6A according to this Variation 1, when radio-frequency signal Sig1having a relatively small PAPR is input to power amplifying circuit10, bias signal b1having a relatively low tracking property is applied from APT power supply circuits34and36to power amplifying circuit10. On the other hand, when radio-frequency signal Sig2having a relatively large PAPR is input to power amplifying circuit10, bias signal b2having a relatively high tracking property is applied from ET power supply circuits33and35to power amplifying circuit10.

It should be noted that, from the viewpoint of the tracking property described above, in radio-frequency circuit1A and communication device6A according to this Variation 1, ET power supply circuits33and35may be disposed closer to RFIC4than APT power supply circuits34and36are. Furthermore, ET power supply circuits33and35may be disposed closer to power amplifying circuit10than APT power supply circuits34and36are. According to this configuration, the control lines connecting RFIC4and ET power supply circuits33and35and the bias signal lines connecting ET power supply circuits33and35and power amplifying circuit10can be made relatively short, and thus it is possible to improve the tracking property of bias signal b2from which a tracking property higher than that of bias signal b1is demanded.

Furthermore, the tracking property (a second tracking degree) of bias signal b2is higher than the tracking property (a first tracking degree) of bias signal b1means that the tracking property of bias signal b2output by ET power supply circuits33and35is higher than the tracking property of bias signal b1output by APT power supply circuits34and36. In order to realize this, for example, the dynamic range of bias voltages to be output from ET power supply circuits33and35may be larger than the dynamic range of bias voltages output from APT power supply circuits34and36. Furthermore, for example, the response speed from when control signals03and05are detected to when the bias voltages are output by ET power supply circuits33and35may be higher than the response speed from when control signals04and06are detected to when the bias voltages are output by APT power supply circuits34and36.

It should be noted that although amplification mode switching circuit3A is included in communication device6A and is outside radio-frequency circuit1A in this Variation 1, the present disclosure is not limited to this configuration. Radio-frequency circuit1A may include amplification mode switching circuit3A. In addition, radio-frequency circuit1A may include switches31and32of amplification mode switching circuit3A. For example, switches31and32may be mounted on the mounting board of radio-frequency circuit1A. Specifically, radio-frequency circuit1A according to this variation may further include switch31that switches between supplying bias signal b1corresponding to the APT mode to power amplifier11and supplying bias signal b2corresponding to the ET mode to power amplifier11, and switch32that switches between supplying bias signal b1corresponding to the APT mode to power amplifier12and supplying bias signal b2corresponding to the ET mode to power amplifier12.

The amplification mode of power amplifiers11and12is determined by the supply specification of the bias signals for the amplifier transistors included in power amplifiers11and12. According to the above-described configuration, the supply of bias signals to power amplifiers11and12is switched by switches31and32included in radio-frequency circuit1A, and thus radio-frequency circuit1A capable of switching amplification modes using a simplified circuit configuration can be realized.

It should be noted that although one of radio-frequency signals Sig1and Sig2is a signal used in 4G and the other of radio-frequency signals Sig1and Sig2is a signal used in 5G in radio-frequency circuit1A according to this variation, they are not limited to such signals. In radio-frequency circuit1A according to this Variation 1, radio-frequency signal Sig1may be a signal used in 4G and radio-frequency signal Sig2may also be a signal used in 4G.

According to this configuration, the ET mode promotes low power consumption in the amplification of radio-frequency signal Sig1of 4G-LTE which has a narrow channel bandwidth, and the APT mode enables the reduction of signal distortion in the amplification of radio-frequency signal Sig2of 4G-LTE which has a narrow channel bandwidth. Therefore, in radio-frequency circuit1A and communication device6A that transfer 4G-LTE radio-frequency signals, signal distortion can be reduced.

In radio-frequency circuit1A according to this variation, radio-frequency signal Sig1may be a signal used in 5G and radio-frequency signal Sig2may also be a signal used in 5G.

According to this configuration, the APT mode promotes low power consumption in the amplification of radio-frequency signal Sig1of 5G-NR which has a narrow channel bandwidth, and the ET mode enables the reduction of signal distortion in the amplification of radio-frequency signal Sig2of 5G-NR which has a narrow channel bandwidth. Therefore, in radio-frequency circuit1A and communication device6A that transfer 5G-NR radio-frequency signals, signal distortion can be reduced.

Furthermore, in radio-frequency circuit1A according to this Variation 1, the case where radio-frequency signal Sig1used in 4G and radio-frequency signal Sig2used in 5G can be simultaneously transmitted is given as an example, radio-frequency circuit1A can also be applied to a case where radio-frequency signals used in two different channels conforming to mobile communication systems of the same generation can be simultaneously transmitted (what is called carrier aggregation). Specifically, radio-frequency circuit1A can also be applied to (1) the case of simultaneously transmitting radio-frequency signal Sig1used in 4G and radio-frequency signal Sig2used in 4G and (2) the case of simultaneously transmitting radio-frequency signal Sig1used in 5G and radio-frequency signal Sig2used in 5G.

4. Configuration of Radio-Frequency Circuit1A and Communication Device6A According to Variation 1 (Second Application Example)

It should be noted that, as a second application example of radio-frequency circuit1A according to Variation 1, power amplifying circuit10may be a transmission amplifying circuit capable of amplifying radio-frequency signal Sig1(a first radio-frequency signal) of a first communication band having band bandwidth BW1and radio-frequency signal Sig2(a second radio-frequency signal) of a second communication band having a band bandwidth BW2which is greater than band bandwidth BW1. Specifically, instead of switching amplification modes according to radio-frequency signals Sig1and Sig2having channel bandwidths that are in a wideness/narrowness relation, power amplifying circuit10may switch amplification modes according to radio-frequency signals Sig1and Sig2having communication band frequency bands that are in a wideness/narrowness relation.

At this time, in radio-frequency circuit1A according to this Variation 1, for example, power amplifier11amplifies radio-frequency signal Sig1in the amplification mode according to the APT method, and power amplifier12amplifies radio-frequency signal Sig2in the amplification mode according to the ET method. In this case, the passband of filter circuit13corresponds to band bandwidth BW1, and the passband of filter circuit14corresponds to band bandwidth BW2. Furthermore, the gain bandwidth of power amplifier11corresponds to band bandwidth BW1, and the gain bandwidth of power amplifier12corresponds to band bandwidth BW2. It should be noted that in this disclosure, a gain bandwidth is defined as the bandwidth in which a power amplifier is capable of amplifying a radio-frequency signal by at least a predetermined gain.

In the second application example of radio-frequency1A according to this variation, for example, the communication bands illustrated inFIG.3Bare applied. For example, a signal of 4G-LTE (Band 25-Tx) having band bandwidth BW1of 65 MHz is applied as radio-frequency signal Sig1, and a signal of 5G-NR (n41) having band bandwidth BW2of 194 MHz as radio-frequency signal Sig2. In other words, the band bandwidth of 5G-NR (n41) is greater than the band bandwidth of 4G-LTE (Band 25-Tx). Since the channel bandwidth tends to be wider with a wider band bandwidth, in the case of the second application example, the channel bandwidth of 5G-NR (n41) tends to be wider than the channel bandwidth of 4G-LTE (Band 25-Tx), and thus signal distortion becomes bigger in the radio-frequency signal of 5G-NR (n41). It should be noted that radio-frequency signals Sig1and Sig2are not limited to the above-described communication band allocation.

In the second application example of radio-frequency circuit1A according to this Variation 1, for example, the communication band allocation indicated in Table 1 may be applied. For example, a signal of 4G-LTE (Band 25-Tx) is applied as radio-frequency signal Sig1, and a signal of 5G-NR (n41) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal of 4G-LTE (Band 5-Tx) is applied as radio-frequency signal Sig1, and a signal of 5G-NR (n78) is applied as radio-frequency signal Sig2. Furthermore, for example, a signal of 5G-NR (n5-Tx) is applied as radio-frequency signal Sig1, and a signal of 4G-LTE (B3-Tx) is applied as radio-frequency signal Sig2.

As the frequency bandwidth of the radio-frequency signal to be amplified by the power amplifier becomes wider, the frequency for which the power amplifier has to perform amplification becomes a wider band, and thus the signal distortion component of the amplified radio-frequency signal becomes bigger. In particular, the wider the channel bandwidth of the radio-frequency signal to be amplified by the power amplifier is, the bigger the signal distortion component of the amplified radio-frequency signal becomes. Whereas, although signal distortion is generated in the ET mode, the APT mode, though inferior to the ET mode in terms of reducing power consumption, can reduce the generation of signal distortion compared to the ET mode.

According to the second application example of this Variation 1, radio-frequency signal Sig1having relatively narrow channel bandwidth BW1(the channel bandwidth tends to be narrow) is amplified in the ATP mode and radio-frequency signal Sig2having relatively wide channel bandwidth BW2(the channel bandwidth tends to be wide) is amplified in the ET mode. According to this configuration, the APT mode reduces signal distortion in the amplification of radio-frequency signal Sig1of 4G-LTE (Band 25-Tx) for which power consumption tends to be small and the ET mode enables the reduction of power consumption in the amplification of radio-frequency signal Sig2of 5G-NR (n41) for which power consumption tends to become big. Therefore, radio-frequency circuit1A and communication device6A that reduce the power consumption of power amplifying circuit10can be provided.

It should be noted that in radio-frequency circuit1A according to this Variation 1, the amplification of radio-frequency signal Sig1by power amplifier11and the amplification of radio-frequency signal Sig2by power amplifier12can be simultaneously executed. According to this configuration, the signal distortion of radio-frequency signal Sig2which has a wide band bandwidth can be reduced while simultaneously amplifying two radio-frequency signals having different band bandwidths.

Furthermore, in this variation, power amplifier11amplifies one of radio-frequency signal Sig1and radio-frequency signal Sig2, and power amplifier12amplifies the other of radio-frequency signal Sig1and radio-frequency signal Sig2, but are not limited to this configuration. In radio-frequency circuit1A, power amplifier11may amplify radio-frequency signal Sig2and power amplifier12may amplify radio-frequency signal Sig1, or it is acceptable that each of power amplifiers11and12can amplify either radio-frequency signals Sig1or Sig2. Specifically, when power amplifier11amplifies one of radio-frequency signals Sig1and Sig2, power amplifier12may amplify the other of radio-frequency signals Sig1and Sig2. For this reason, the amplification of radio-frequency signal Sig2by power amplifier11and the amplification of radio-frequency signal Sig1by power amplifier12can be simultaneously executed.

The correspondence relation between power amplifiers11and12and radio-frequency signals Sig1and Sig2may be determined by RFIC4.

It should be noted that the elements included in communication device6A other than radio-frequency circuit1A in the second application example are the same in the first application example of Variation 1, and thus their description is omitted.

5. Configuration of Radio-Frequency Circuit1B and Communication Device6B According to Variation 2

FIG.5is a circuit configuration diagram of radio-frequency circuit1B and communication device6B according to Variation 2 of the embodiment inFIG.1. As illustrated in the figure, communication device6B includes radio-frequency circuit1B, antenna element21, amplification mode switching circuit3A, power supply7, RFIC4, and BBIC5. Compared to communication device6A according to Variation 1, communication device6B according to this Variation 2 is different only in the configuration of the antenna circuit. Hereinafter, the description of communication device6B according to this Variation 2 will omit the elements that are the same as in communication device6A according to Variation 1 and will focus on those elements that are different.

Antenna element21is connected to output terminals110and120of radio-frequency circuit1B, transmits the radio-frequency signals amplified by power amplifiers11and12, and receives a radio-frequency signal transmitted from another communication device (a base station, and the like). The radio-frequency signal output from power amplifier11and the radio-frequency signal output from power amplifier12are transmitted from the same antenna element21. Therefore, a small-sized communication device6B that reduces signal distortion of a radio-frequency signal can be provided.

As described above, according to this embodiment and the variations, radio-frequency circuit1includes power amplifying circuit10that amplifies radio-frequency signal Sig1having channel bandwidth BW1and radio-frequency signal Sig2having channel bandwidth BW2greater than channel bandwidth BW1. Power amplifying circuit10amplifies radio-frequency signal Sig1in an amplifying mode according to the APT method, and amplifies radio-frequency signal Sig2in an amplifying mode according to the ET method.

According to this configuration, radio-frequency signal Sig2which has a wider channel bandwidth than radio-frequency signal Sig1is amplified in the ET mode, and thus the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2having a wide channel bandwidth can be reduced.

According to this configuration, the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a wide channel bandwidth can be reduced while amplifying two radio-frequency signals having different channel bandwidths by time division.

Furthermore, power amplifying circuit10may include power amplifiers11and12. Power amplifier11may amplify one of radio-frequency signal Sig1and radio-frequency signal Sig2, and power amplifier12may amplify the other of radio-frequency signal Sig1and radio-frequency signal Sig2. Radio-frequency circuit1A may be capable of simultaneously amplifying radio-frequency signal Sig1and radio-frequency signal Sig2.

According to this configuration, the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a wide channel bandwidth can be reduced while simultaneously amplifying two radio-frequency signals having different channel bandwidths.

Furthermore, radio-frequency circuit1A may further include output terminal110through which a radio-frequency signal amplified by power amplifier11is output, and output terminal120through which a radio-frequency signal amplified by power amplifier12is output. Output terminal110and output terminal120may be connected to mutually different antenna elements22and23, respectively.

According to this configuration, the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a wide channel bandwidth can be reduced while ensuring high isolation between two radio-frequency signals having different channel bandwidths.

Furthermore, according to this embodiment, radio-frequency circuit1includes power amplifying circuit10that amplifies radio-frequency signal Sig1of a first communication band having communication bandwidth BW1and radio-frequency signal Sig2of a second communication band having communication bandwidth BW2wider than communication bandwidth BW1. Power amplifying circuit10amplifies radio-frequency signal Sig1in an amplification mode according to the APT method, and amplifies radio-frequency signal Sig2in an amplifying mode according to ET method.

According to this configuration, radio-frequency signal Sig2which has a wider band bandwidth than radio-frequency signal Sig1is amplified in the APT mode, and thus the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2having a wide band bandwidth can be reduced.

Furthermore, power amplifying circuit10may include power amplifier11, radio-frequency circuit1may further include filter circuit13connected to an output terminal of the first power amplifier, and filter circuit13may have a passband that includes a frequency band of the first communication band and a frequency band of the second communication band.

According to this configuration, the power consumption of power amplifying circuit10when amplifying a radio-frequency signal having a wide bandwidth can be reduced while amplifying two radio-frequency signals having different communication bands by time division.

Furthermore, power amplifying circuit10may include: power amplifier11that amplifies radio-frequency signal Sig1; and power amplifier12that amplifies radio-frequency signal Sig2. Radio-frequency circuit1A may further include filter circuit13connected to an output terminal of power amplifier11and having a passband that includes a frequency band of the first communication band, and filter circuit14connected to an output terminal of power amplifier12and having a passband that includes a frequency band of the second communication band, and radio-frequency circuit1A may be capable of simultaneously amplifying radio-frequency signal Sig1and radio-frequency signal Sig2.

According to this configuration, the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a wide band bandwidth can be reduced while simultaneously amplifying two radio-frequency signals having different band bandwidths.

Furthermore, in radio-frequency circuits1,1A, and1B, radio-frequency signal Sig1may be a signal used in 4G, and radio-frequency signal Sig2may be a signal used in 5G.

According to this configuration, simultaneous transfer of 4G and 5G (EN-DC: E-UTRA-NR-dual connectivity) can be executed while reducing the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a relatively wide channel bandwidth or band bandwidth.

Furthermore, radio-frequency signal Sig1may be a signal used in 4G, and radio-frequency signal Sig2may be a signal of WLAN.

Furthermore, the PAPR of radio-frequency signal Sig2may be larger than the PAPR of radio-frequency signal Sig1.

Furthermore, radio-frequency signal Sig1may be a signal of WLAN, and radio-frequency signal Sig2may be a signal used in 5G.

Furthermore, in radio-frequency circuits1,1A, and1B, radio-frequency signal Sig1may be a signal used in 4G, and radio-frequency signal Sig2may be a signal used in 4G.

According to this configuration, 4G carrier aggregation can be executed while reducing the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a relatively wide channel bandwidth or band bandwidth.

Furthermore, in radio-frequency circuits1,1A, and1B, radio-frequency signal Sig1may be a signal used in 5G, and radio-frequency signal Sig2may be a signal used in 5G.

According to this configuration, 5G carrier aggregation can be executed while reducing the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2which has a relatively wide channel bandwidth or band bandwidth.

Furthermore, when a value indicating the output power of the radio-frequency signal output from power amplifying circuit10is greater than a threshold power, radio-frequency signal Sig1may be amplified in an amplification mode according to the APT method and radio-frequency signal Sig2may be amplified in an amplification mode according to the ET method.

According to this configuration, in the high output region in which power consumption becomes high, radio-frequency signal Sig2which has a greater channel bandwidth or band bandwidth than radio-frequency signal Sig1is amplified in the ET mode, and thus of the power consumption of power amplifying circuit10when amplifying radio-frequency signal Sig2can be effectively reduced.

According to this configuration, communication device6that reduces power consumption when amplifying radio-frequency signal Sig2which has a relatively wide channel bandwidth can be provided.

Furthermore, RFIC4may include a controller that outputs a control signal for causing power amplifying circuit10to operate in one of the amplification mode according to the ET method and the amplification mode according to the APT method, based on information indicating which one of radio-frequency signal Sig1and radio-frequency signal Sig2is to be input to radio-frequency circuit1. Communication device6may further include amplification mode switching circuit3which is disposed between the controller and power amplifying circuit10and switches between supplying bias signal b2corresponding to the APT method and supplying bias signal b1corresponding to the ET method, to power amplifying circuit10, based on the control signal output from the controller.

According to this configuration, the power consumption of power amplifying circuit10can be reduced using a simplified circuit configuration.

OTHER EMBODIMENTS

Although the radio-frequency circuit and the communication device according to the present disclosure has been described above based on an exemplary embodiment and variations thereof, the radio-frequency circuit and the communication device according to the present disclosure are not limited to the foregoing embodiment and variations thereof. The present disclosure also encompasses other embodiments achieved by combining arbitrary elements in the above embodiment and variations thereof, variations resulting from various modifications to the embodiment and variations thereof that may be conceived by those skilled in the art without departing from the essence of the present disclosure, and various devices that include the radio-frequency circuit and the communication device according to the present disclosure.

Furthermore, although in the foregoing embodiment and variations thereof, the configuration for the case of transmitting two radio-frequency signals having different band bandwidths or two radio-frequency signals having different channel bandwidths is given, the configuration of the radio-frequency circuit and communication device according to the present disclosure can also be applied to the case of transmitting three radio-frequency signals having different band bandwidths or three radio-frequency signals having different channel bandwidths.

Furthermore, for example, in the radio-frequency circuit and communication device according to the foregoing embodiment and variations thereof, another radio-frequency circuit element and wiring may be inserted in a path connecting respecting circuit elements and signal paths which are disclosed in the drawings.

Furthermore, the controller according to the present disclosure may be realized as an integrated circuit (IC) or large scale integration (LSI). Furthermore, the method of implementation of structural elements using an integrated circuit may be realized using a dedicated circuit or a general-purpose processor. A field programmable gate array (FPGA) that allows for programming after the manufacture of an LSI, or a reconfigurable processor that allows for reconfiguration of the connection and the setting of circuit cells inside an LSI may be employed. When circuit integration technology that replaces LSIs comes along owing to advances of the semiconductor technology or to a separate derivative technology, the function blocks may understandably be integrated using that technology.

The present disclosure can be widely used in communication apparatuses such as a mobile phone, as a multiband/multimode-compatible front-end module.