High-frequency circuit and communication device

Abstract

A high-frequency circuit (1) is provided with: a switch (51) having selection terminals (51b, 51c); a switch (52); a filter (31) connected to the selection terminal (51b); a filter (32) connected to the selection terminal (51c); and a filter (33). The switch (52) is connected in series between the filter (33) and a path connecting the selection terminal (51c) and the filter (32).

Description

Technical Field

[0001] The present invention relates to a high-frequency circuit and a communication device. Background Art

[0002] Patent Document 1 discloses a structure including: a switch having a plurality of selection terminals; and filters connected to the plurality of selection terminals, respectively.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2019-528656 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, in the above-mentioned prior art, there is a concern that the loss cannot be reduced.

[0008] Therefore, an object of the present invention is to provide a high-frequency circuit and a communication device capable of reducing loss.

[0009] Solutions for solving problems

[0010] A high-frequency circuit according to one embodiment of the present invention comprises: a first switch having a first selection terminal and a second selection terminal; a second switch; a first filter connected to the first selection terminal; a second filter connected to the second selection terminal; and a third filter, wherein the second switch is connected in series between a path connecting the second selection terminal and the second filter and the third filter.

[0011] A high-frequency circuit according to another embodiment of the present invention comprises: a first switch having a first selection terminal and a second selection terminal; a second switch; a first filter connected to the first selection terminal; a second filter connected to the second selection terminal; and an external connection terminal, wherein the second switch is connected in series between a path connecting the second selection terminal and the second filter and the external connection terminal.

[0012] Another embodiment of the present invention involves a high-frequency circuit comprising: a first switch having a first selection terminal and a second selection terminal; a second switch of SPST (Single Pole Single Throw) type; a first filter connected to the first selection terminal; a second filter connected to the second selection terminal; and a third filter, wherein the second switch is connected in series between a path connecting the second selection terminal and the second filter and the third filter, and the third filter has a passband including a frequency band of SDL (Supplementary DownLink).

[0013] A communication device according to one aspect of the present invention includes: the high-frequency circuit according to the above-mentioned aspect; and an RF signal processing circuit that processes a high-frequency signal transmitted through the high-frequency circuit.

[0014] Effects of the Invention

[0015] According to the present invention, loss can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a circuit configuration diagram of a high-frequency circuit and a communication device according to Embodiment 1.

[0017] Figure 2 2 is a circuit configuration diagram of a high-frequency circuit according to a comparative example.

[0018] Figure 3 It is a circuit configuration diagram of a high-frequency circuit according to Modification 1 of Embodiment 1.

[0019] Figure 4 This is a circuit configuration diagram of a high-frequency circuit according to a second variation of the first embodiment.

[0020] Figure 5 This is a circuit configuration diagram of a high-frequency circuit according to Modification 3 of Embodiment 1.

[0021] Figure 6 This is a circuit configuration diagram of a high-frequency circuit and a communication device according to the second embodiment.

[0022] Figure 7 It is a circuit configuration diagram of a high-frequency circuit according to a modification of the second embodiment.

[0023] Figure 8 It is a circuit configuration diagram of a high-frequency circuit according to the third embodiment.

[0024] Fig. 9 It is a circuit configuration diagram of a high-frequency circuit according to a modification of the third embodiment. DETAILED DESCRIPTION

[0025] The high-frequency circuit and communication device involved in the embodiments of the present invention are described in detail using the accompanying drawings. In addition, the embodiments described below all represent a specific example of the present invention. Therefore, the numerical values, shapes, materials, structural elements, configurations and connection methods of structural elements, steps, and the order of steps shown in the following embodiments are examples, and their purpose is not to limit the present invention. Therefore, the structural elements of the following embodiments that are not recorded in the independent claims are described as arbitrary structural elements.

[0026] In addition, each figure is a schematic diagram and may not be strictly illustrated. Therefore, for example, the scales in each figure may not be consistent. In addition, in each figure, the same symbols are marked for substantially the same structure, and repeated descriptions are omitted or simplified.

[0027] In addition, in this specification, "connection" includes not only direct connection using connection terminals and / or wiring conductors, but also electrical connection via other circuit elements. In addition, "connection between A and B" means connection between A and B and both A and B.

[0028] In addition, in this specification, unless otherwise specified, ordinal numbers such as "first" and "second" do not indicate the number or order of constituent elements, but are used to avoid confusion between similar constituent elements and to distinguish them.

[0029] In addition, in this specification, a "transmission path" refers to a transmission line composed of a wiring that transmits a high-frequency transmission signal, an electrode directly connected to the wiring, and a terminal directly connected to the wiring or the electrode. In addition, a "reception path" refers to a transmission line composed of a wiring that transmits a high-frequency reception signal, an electrode directly connected to the wiring, and a terminal directly connected to the wiring or the electrode. In addition, a "transmission reception path" refers to a transmission line composed of a wiring that transmits both a high-frequency transmission signal and a high-frequency reception signal, an electrode directly connected to the wiring, and a terminal directly connected to the wiring or the electrode.

[0030] (Implementation Method 1)

[0031] [1.1 Circuit Configuration of High Frequency Circuit 1 and Communication Device 4]

[0032] First, use Figure 1 The circuit configurations of the high-frequency circuit 1 and the communication device 4 according to the first embodiment will be described. Figure 1 It is a circuit configuration diagram of the high-frequency circuit 1 and the communication device 4 according to the present embodiment.

[0033] [1.1.1 Circuit Configuration of Communication Device 4]

[0034] First, the circuit configuration of the communication device 4 will be described. Figure 1 The communication device 4 shown is a device used in the communication system, for example, a portable terminal such as a smart phone or a tablet computer. Figure 1 As shown, the communication device 4 according to the present embodiment includes a high frequency circuit 1, an antenna 2, and an RF signal processing circuit (RFIC) 3. In addition, the communication device 4 includes a plurality of low noise amplifiers 21, 22, and 23.

[0035] The high frequency circuit 1 transmits a high frequency signal between the antenna 2 and the RFIC 3. In this embodiment, the high frequency circuit 1 transmits a reception signal as an example of a high frequency signal. In addition, the high frequency circuit 1 may also transmit a transmission signal as an example of a high frequency signal. The detailed structure of the high frequency circuit 1 will be described later.

[0036] The antenna 2 is connected to the antenna connection terminal 100 of the high frequency circuit 1, receives a high frequency signal from the outside, and outputs it to the high frequency circuit 1. The antenna 2 can also transmit the high frequency signal output from the high frequency circuit 1.

[0037] RFIC 3 is an example of a signal processing circuit that processes a high-frequency signal. Specifically, RFIC 3 performs signal processing on a high-frequency reception signal input through a reception path of a high-frequency circuit 1 by down-conversion, etc., and outputs the reception signal generated after the signal processing to a baseband signal processing circuit (BBIC, not shown). In addition, RFIC 3 may also perform signal processing on a transmission signal input from BBIC by up-conversion, etc., and output the high-frequency transmission signal generated after the signal processing to the transmission path of the high-frequency circuit 1. In addition, RFIC 3 has a control unit that controls switches and amplifiers, etc., of the high-frequency circuit 1. In addition, part or all of the functions of RFIC 3 as a control unit may also be installed outside RFIC 3, for example, it may also be installed on the BBIC or the high-frequency circuit 1.

[0038] The low noise amplifiers 21, 22, and 23 are examples of amplifiers that amplify high frequency signals, respectively, and amplify the received signals transmitted in the high frequency circuit 1. The low noise amplifier 21 is connected to the high frequency output terminal 121 of the high frequency circuit 1, and amplifies the received signals output from the high frequency output terminal 121. The low noise amplifier 22 is connected to the high frequency output terminal 122 of the high frequency circuit 1, and amplifies the received signals output from the high frequency output terminal 122. The low noise amplifier 23 is connected to the high frequency output terminal 123 of the high frequency circuit 1, and amplifies the received signals output from the high frequency output terminal 123. The low noise amplifiers 21, 22, and 23 amplify the received signals of different communication frequency bands, respectively. The low noise amplifiers 21, 22, and 23 can also be mounted on the same substrate as the high frequency circuit 1 and modularized.

[0039] Figure 1 The circuit configuration of the communication device 4 shown in FIG. 1 is an example and is not limited thereto. For example, the communication device 4 may not include the antenna 2 . Alternatively, the communication device 4 may include a plurality of antennas 2 .

[0040] In addition, the communication device 4 may not include the low-noise amplifiers 21, 22, and 23. For example, the communication device 4 may include one low-noise amplifier that amplifies reception signals of a plurality of communication frequency bands.

[0041] [1.1.2 Circuit structure of high frequency circuit 1]

[0042] Next, the circuit configuration of the high-frequency circuit 1 according to the present embodiment will be described.

[0043] like Figure 1 As shown, the high-frequency circuit 1 includes filters 31 , 32 , and 33 , switches 51 and 52 , an antenna connection terminal 100 , and high-frequency output terminals 121 , 122 , and 123 .

[0044] The antenna connection terminal 100 is connected to the antenna 2 .

[0045] The high frequency output terminal 121 is connected to the RFIC 3 via the low noise amplifier 21 . The high frequency output terminal 121 is a terminal for outputting a reception signal received by the antenna 2 and transmitted in the high frequency circuit 1 to the low noise amplifier 21 .

[0046] The high frequency output terminal 122 is connected to the RFIC 3 via the low noise amplifier 22. The high frequency output terminal 122 is a terminal for outputting a reception signal received by the antenna 2 and transmitted in the high frequency circuit 1 to the low noise amplifier 22.

[0047] The high frequency output terminal 123 is connected to the RFIC 3 via the low noise amplifier 23. The high frequency output terminal 123 is a terminal for outputting a reception signal received by the antenna 2 and transmitted in the high frequency circuit 1 to the low noise amplifier 23.

[0048] The filters 31, 32, and 33 are reception filters each having a passband including at least a part of a predetermined communication frequency band. The passbands of the filters 31, 32, and 33 are different from each other.

[0049] The communication frequency band refers to, for example, a frequency band predefined by a standardization organization (e.g., 3GPP (registered trademark) (3rd Generation Partnership Project), IEEE (Institute of Electrical and Electronics Engineers), etc.) for a communication system constructed using a radio access technology (RAT: Radio Access Technology). In the present embodiment, as a communication system, for example, a 4G-LTE (4th Generation-Long Term Evolution: 4th Generation Long Term Evolution) system, a 5G-NR (5th Generation-New Radio: 5th Generation New Radio) system, and a WLAN (Wireless Local Area Network: Wireless Local Area Network) system can be used, but it is not limited to these.

[0050] The filter 31 is an example of a first filter, and has a passband including a first frequency band. The input end of the filter 31 is connected to the selection terminal 51b of the switch 51. There is no switch connected in series on the path between the filter 31 and the selection terminal 51b that connects the filter 31 and the selection terminal 51b. The output end of the filter 31 is connected to the high-frequency output terminal 121.

[0051] The first frequency band is, for example, a downlink operating frequency band (2110 MHz-2170 MHz) of frequency band B1 for LTE or a downlink operating frequency band (2110 MHz-2170 MHz) of frequency band n1 for 5G-NR.

[0052] The filter 32 is an example of a second filter, and has a passband including a second frequency band. The input end of the filter 32 is connected to the selection terminal 51c of the switch 51. There is no switch connected in series on the path between the filter 32 and the selection terminal 51c that connects the filter 32 and the selection terminal 51c. The output end of the filter 32 is connected to the high-frequency output terminal 122.

[0053] The second frequency band is a frequency band different from the first frequency band. The second frequency band is, for example, a downlink operating frequency band (1805 MHz-1880 MHz) of frequency band B3 for LTE or a downlink operating frequency band (1805 MHz-1880 MHz) of frequency band n3 for 5G-NR.

[0054] The filter 33 is an example of a third filter and has a passband including a third frequency band. The input end of the filter 33 is connected to the selection terminal 51c of the switch 51 via the switch 52. The output end of the filter 33 is connected to the high-frequency output terminal 123.

[0055] The third frequency band is a frequency band different from both the first frequency band and the second frequency band. For example, the third frequency band is a frequency band that does not overlap with the second frequency band. In this embodiment, the third frequency band is a frequency band of SDL (Supplementary DownLink). The third frequency band is, for example, frequency band B32 (1452MHz-1496MHz) used for LTE, or frequency band n75 (1432MHz-1517MHz) or frequency band n76 (1427MHz-1432MHz) used for 5G-NR.

[0056] The switch 51 is an example of a first switch, and has a common terminal 51a and selection terminals 51b and 51c. The switch 51 switches between connection (conduction) and non-connection (non-conduction) of the common terminal 51a and the selection terminals 51b and 51c. The common terminal 51a is connected to the antenna connection terminal 100. The selection terminal 51b is an example of a first selection terminal, and is connected to the filter 31. The selection terminal 51c is an example of a second selection terminal, and is connected to the filter 32 and the switch 52, respectively. The switch 51 is also called an antenna switch. The switch 51 is a SPDT (Single-Pole Double-Throw) type switch circuit. In addition, the switch 51 can also be a multi-connection type switch circuit. That is, the common terminal 51a can also be connected to both the selection terminals 51b and 51c at the same time.

[0057] The switch 52 is an example of a second switch. The switch 52 is connected in series between the path connecting the selection terminal 51c of the switch 51 and the filter 32 and the filter 33. Specifically, the switch 52 is connected in series between the node N1 located on the path connecting the selection terminal 51c and the filter 32 and the filter 33. In addition, the node N1 may also be consistent with the selection terminal 51c or the input end of the filter 32. The switch 52 can switch the connection and non-connection between the selection terminal 51c (node ​​N1) and the filter 33. The switch 52 is a SPST (Single-Pole Single-Throw) type switch circuit.

[0058] [1.2 Action]

[0059] Next, refer to Figure 1 The operation of the high-frequency circuit 1 according to the present embodiment will be described.

[0060] The high frequency circuit 1 has a single transmission mode and a simultaneous transmission mode.

[0061] In the single transmission mode, a high frequency signal of one communication frequency band is transmitted. Specifically, in the single transmission mode, by controlling switches 51 and 52, only one of the filters 31 and 32 is operated. In addition, the operation of the filter means that a high frequency signal of the passband of the filter can be transmitted. The switches 51 and 52 are controlled by a control unit not shown.

[0062] For example, by connecting the common terminal 51a of the switch 51 to the selection terminal 51b, only the filter 31 operates. Also, by connecting the common terminal 51a of the switch 51 to the selection terminal 51c and making the switch 52 non-conductive (off state), only the filter 32 operates.

[0063] In the present embodiment, filter 33 is a filter including the SDL frequency band in the passband, and is a filter that operates in an auxiliary manner. Therefore, filter 33 does not operate independently. That is, a single transmission is not performed only for the signal that passes through filter 33. The signal that passes through filter 33 is transmitted simultaneously with the signal that passes through filter 32. In other words, filter 33 is used as an auxiliary filter of filter 32, and is a filter that does not operate independently.

[0064] In the simultaneous transmission mode, high frequency signals of a plurality of communication frequency bands are transmitted. Specifically, in the simultaneous transmission mode, switches 51 and 52 are controlled to operate two or more filters among filters 31, 32, and 33.

[0065] For example, by connecting the common terminal 51a of the switch 51 to the selection terminal 51c and making the switch 52 conductive (closed), the two filters 32 and 33 are operated. In addition, when the switch 51 is a multi-connection type switch circuit, the common terminal 51a can be connected to both the selection terminals 51b and 51c. For example, by connecting the common terminal 51a of the switch 51 to the selection terminals 51b and 51c, respectively, and making the switch 52 non-conductive, the two filters 31 and 32 are operated. In addition, by connecting the common terminal 51a of the switch 51 to the selection terminals 51b and 51c, respectively, and making the switch 52 conductive, the three filters 31, 32 and 33 are operated.

[0066] [1.3 Effects, etc.]

[0067] Next, effects and the like of the high-frequency circuit 1 according to the present embodiment will be described in comparison with a comparative example.

[0068] Figure 2 is a circuit diagram of a high frequency circuit 1x according to a comparative example. Figure 2As shown, the high-frequency circuit 1 x according to the comparative example includes a switch 51 x instead of the switches 51 and 52 , compared with the high-frequency circuit 1 according to the embodiment.

[0069] The switch 51x has a common terminal 51a and selection terminals 51b, 51c, and 51d. The switch 51x switches between connection and non-connection of the common terminal 51a and the selection terminals 51b, 51c, and 51d. Similar to the switch 51 of the high-frequency circuit 1, the common terminal 51a, the selection terminals 51b, and 51c are connected to the antenna connection terminal 100, the input end of the filter 31, and the input end of the filter 32, respectively. The selection terminal 51d is connected to the input end of the filter 33. That is, in the high-frequency circuit 1x involved in the comparative example, the input end of the filter 33 is directly connected to the selection terminal 51d of the switch 51x without passing through the switch 52.

[0070] The switch 51x is a multi-connection type switch circuit. That is, the common terminal 51a can be connected to one or more of the selection terminals 51b, 51c, and 51d. Thus, in the high-frequency circuit 1x involved in the comparative example, by controlling the switch 51x, the above-mentioned single transmission mode and simultaneous transmission mode can be performed in the same manner as the high-frequency circuit 1 involved in the embodiment.

[0071] Here, the following case is assumed: the filter 31 operates in the single transmission mode. In this case, in the high-frequency circuit 1x involved in the comparative example, the common terminal 51a of the switch 51x is not connected to the selection terminals 51c and 51d. Therefore, off capacitance is formed between the common terminal 51a and the selection terminal 51c and between the common terminal 51a and the selection terminal 51d. Since two off capacitances are connected in parallel to the common terminal 51a, the signal leaks to each filter in the filters 32 and 33, and the loss increases.

[0072] In contrast, in the high-frequency circuit 1 of the present embodiment, when the filter 31 is in operation, the only selection terminal to which the common terminal 51a is not connected is the selection terminal 51c. In other words, in the high-frequency circuit 1, the number of terminals of the selection terminal of the switch 51 is reduced compared to the high-frequency circuit 1x of the comparative example. Here, the filter 33 is connected to the selection terminal 51c via the switch 52. That is, the switch 52 is connected in series between the path connecting the selection terminal 51c and the filter 32 and the filter 33. Therefore, when the filter 31 is in operation, for the common terminal 51a, only the disconnection capacitance caused by the selection terminal 51c is seen, and the disconnection capacitance of the switch 52 for making the filter 33 inoperative is not seen. Therefore, the signal leaking to the filters 32 and 33 can be reduced, thereby reducing the loss.

[0073] As described above, the high frequency circuit 1 according to the present embodiment includes: the switch 51 having the selection terminals 51b and 51c; the switch 52; the filter 31 connected to the selection terminal 51b; the filter 32 connected to the selection terminal 51c; and the filter 33. The switch 52 is connected in series between the path connecting the selection terminal 51c and the filter 32 and the filter 33.

[0074] Since the filter 33 is connected to the selection terminal 51c via the switch 52, the off capacitance of the switch 52 is not visible when only the filter 31 is operated. Therefore, the signal leaking to the filters 32 and 33 can be reduced, and the loss can be reduced.

[0075] In addition, for example, the filter 33 has a passband including the frequency band of SDL.

[0076] Thus, the filter 33 is a frequency band dedicated to the downlink and does not have a corresponding uplink operating frequency band. Therefore, it is not necessary to meet the attenuation requirement of the uplink operating frequency band that should be located nearby, so the filter design can be simplified. Therefore, the filter 33 can be miniaturized, which can contribute to the miniaturization of the high-frequency circuit 1.

[0077] In addition, for example, single transmission only for the signal that has passed through the filter 33 is not performed.

[0078] Thus, the filter 33 is not used in the single transmission mode, and therefore a dedicated selection terminal (eg, Figure 2 Therefore, the off capacitance when the filter 33 is not operated can be reduced, thereby reducing the loss.

[0079] In addition, for example, the switch 51 has a common terminal 51a, and can switch between the connection between the common terminal 51a and the selection terminal 51b and the connection between the common terminal 51a and the selection terminal 51c. The switch 52 is configured to be turned on when the common terminal 51a is connected to the selection terminal 51c. That is, the signal passing through the filter 33 can be transmitted simultaneously with the signal passing through the filter 32.

[0080] Thus, the filter 32 and the filter 33 can be connected to the same selection terminal 51c, so that the number of selection terminals of the switch 51 can be reduced. Therefore, the off capacitance when the filter 33 is not operated can be reduced, and the loss can be reduced.

[0081] In addition, the communication frequency band included in the passband of each of the filters 31 , 32 , and 33 is not limited to the above-mentioned example, and the communication frequency band can be adjusted appropriately according to the specifications required for the high-frequency circuit 1 .

[0082] Furthermore, for example, the communication device 4 according to the present embodiment includes: the high-frequency circuit 1 ; and the RFIC 3 that processes the high-frequency signal transmitted through the high-frequency circuit 1 .

[0083] Thus, since the high-frequency circuit 1 is provided, the signal leaking to the filters 32 and 33 when the filter 31 is operated can be reduced, and the loss can be reduced.

[0084] [1.4 Modifications]

[0085] Next, a modification of Embodiment 1 will be described. In the following description, differences from Embodiment 1 will be mainly described, and description of common points will be omitted or simplified.

[0086] [1.4.1 Modification 1]

[0087] Figure 3 FIG. 1 is a circuit diagram of a high-frequency circuit 1A according to a first variation of the present embodiment. Figure 3 As shown, the high frequency circuit 1A and Figure 1 Compared with the high-frequency circuit 1 shown, a filter 34 and a high-frequency output terminal 124 are further provided.

[0088] The high frequency output terminal 124 is connected to the RFIC 3 (see Figure 1 The high frequency output terminal 124 is a terminal for outputting a reception signal received by the antenna 2 and transmitted in the high frequency circuit 1A to a low noise amplifier (not shown).

[0089] Filter 34 is an example of a fourth filter, having a passband including a fourth frequency band. The input end of filter 34 is connected to a path connecting switch 52 and filter 33. Specifically, the input end of filter 34 is connected to a node N2 located on a path connecting switch 52 and filter 33. In addition, node N2 may also be consistent with one end of switch 52 (a terminal on the filter 33 side) or the input end of filter 33. The output end of filter 34 is connected to high frequency output terminal 124.

[0090] The fourth frequency band is a frequency band different from the first frequency band, the second frequency band, and the third frequency band. For example, the fourth frequency band is a frequency band that does not overlap with the second frequency band and the third frequency band. As the third frequency band and the fourth frequency band, frequency bands whose attenuation requirements are not located near each other, that is, frequency bands with low design difficulty, can be used.

[0091] In this embodiment, the second frequency band, the third frequency band and the fourth frequency band are all TDD (Time Division Duplex) frequency bands. The second frequency band is, for example, the frequency band B41 (2496MHz-2690MHz) used for LTE or the frequency band n41 (2496MHz-2690MHz) used for 5G-NR. The third frequency band is, for example, the frequency band B34 (2010MHz-2025MHz) used for LTE or the frequency band n34 (2010MHz-2025MHz) used for 5G-NR. The fourth frequency band is, for example, the frequency band B39 (1880MHz-1920MHz) used for LTE or the frequency band n39 (1880MHz-1920MHz) used for 5G-NR.

[0092] In this modification, only one of the filters 33 and 34 may be operated in the single transmission mode. In other words, the filters 33 and 34 may be operated separately. For example, by connecting the common terminal 51a of the switch 51 to the selection terminal 51c and turning on the switch 52, the filters 32, 33, and 34 are in an operable state. Since the filters 32, 33, and 34 are TDD filters, they can be operated separately (single transmission mode), or at least two filters can be operated simultaneously (simultaneous transmission mode).

[0093] As described above, the high-frequency circuit 1A according to the present modification further includes the filter 34 , one end of which is connected to the path connecting the switch 52 and the filter 33 .

[0094] Thus, similarly to the high frequency circuit 1 according to the first embodiment, the filters 33 and 34 are connected to the selection terminal 51c via the switch 52, so that when only the filter 31 is operated, the disconnection capacitance of the switch 52 is not seen. Therefore, the number of signals leaking to the filters 32, 33, and 34 can be reduced, thereby reducing the loss. In addition, the number of filters included in the high frequency circuit 1A increases, thereby increasing the types of signals that can be transmitted (communication frequency bands).

[0095] [1.4.2 Modification 2]

[0096] Figure 4 FIG. 1 is a circuit diagram of a high-frequency circuit 1B according to a second variation of the present embodiment. Figure 4 As shown, the high frequency circuit 1B and Figure 1 Compared with the high-frequency circuit 1 shown, the high-frequency circuit 1 does not include the filter 33 and the high-frequency output terminal 123 , but includes an external connection terminal 140 .

[0097] The external connection terminal 140 is a high-frequency output terminal of the high-frequency circuit 1B, and is a terminal for outputting the reception signal received by the antenna 2 to the outside. For example, when the high-frequency circuit 1B is modularized on a substrate, the external connection terminal 140 is formed using a conductive member such as a bump electrode or a pad provided on the surface of the substrate.

[0098] like Figure 4 As shown, the switch 52 is connected in series between the path connecting the selection terminal 51c of the switch 51 and the filter 32 and the external connection terminal 140. Specifically, the switch 52 is connected in series between the node N1 and the external connection terminal 140. More specifically, the filter 33 is not connected between the selection terminal 51c of the switch 51 and the switch 52 and between the switch 52 and the external connection terminal 140. The filter 33 is connected to the external connection terminal 140 outside the high frequency circuit 1B.

[0099] As described above, the high frequency circuit 1B according to the present modification example includes: the switch 51 having the selection terminals 51b and 51c; the switch 52; the filter 31 connected to the selection terminal 51b; the filter 32 connected to the selection terminal 51c; and the external connection terminal 140. The switch 52 is connected in series between the path connecting the selection terminal 51c and the filter 32 and the external connection terminal 140.

[0100] Thus, similarly to the high-frequency circuit 1 according to the first embodiment, the external connection terminal 140 for connecting the filter 33 is connected to the selection terminal 51c via the switch 52, so that the disconnection capacitance of the switch 52 is not visible when the filter 31 is operating. Therefore, the signal leaking to the filter 32 and the external connection terminal 140 can be reduced, thereby reducing the loss. In addition, the filter 33 can be placed externally relative to the high-frequency circuit 1B, so that the filter 33 with different characteristics can be easily replaced as required.

[0101] In addition, in this modification, the frequency bands included in the passbands of the filters 31, 32, and 33 are the same as those of the high-frequency circuit 1 involved in the first embodiment. For example, the first frequency band of the filter 31 is the downlink operating frequency band of the frequency band B1 or the frequency band n1. The second frequency band of the filter 32 is the downlink operating frequency band of the frequency band B3 or the frequency band n3. The third frequency band of the filter 33 is the frequency band B32 or the frequency band n75 or the frequency band n76. In addition, these are just examples. As in the modification 1, at least one of the filters 31, 32, and 33 may be a TDD frequency band.

[0102] In addition, a low-noise amplifier may be connected to the external connection terminal 140 instead of the filter 33 .

[0103] [1.4.3 Modification 3]

[0104] Figure 5 FIG. 1 is a circuit diagram of a high-frequency circuit 1C according to a third variation of the present embodiment. Figure 5 As shown, the high frequency circuit 1C and Figure 1 Compared with the high-frequency circuit 1 shown, the filter 33 and the high-frequency output terminal 123 are not provided, but a stub 80 is provided.

[0105] The stub 80 is a wiring with a predetermined line length. For example, the line length of the stub 80 is equal to or longer than a quarter of the wavelength of the high-frequency signal. The stub 80 is an open stub, one end of which is connected to the switch 52 and the other end is open.

[0106] like Figure 5 As shown in FIG. 1 , the switch 52 is connected in series between the path connecting the selection terminal 51c of the switch 51 and the filter 32 and the stub 80. Specifically, the switch 52 is connected in series between the node N1 and the stub 80. More specifically, no filter is connected between the switch 52 and the stub 80. In addition, no filter is connected to the other end of the stub 80 (the end on the opposite side to the switch 52).

[0107] The high frequency circuit 1C according to this modification has a single transmission mode and a simultaneous transmission mode, similarly to the high frequency circuit 1 according to the first embodiment. In this case, the impedance when the filter side is viewed from the common terminal 51a of the switch 51 is different when only the filter 31 is operated (single transmission mode) and when both the filters 31 and 32 are operated (simultaneous transmission mode). In this case, the impedance can be adjusted by the stub 80 by switching the switch 52 between conduction and non-conduction.

[0108] For example, the impedance may be adjusted in advance so that when only the filter 31 is operated, the impedance matching can be achieved when the switch 52 is in a non-conductive state. In this case, when the filters 31 and 32 are operated simultaneously, the impedance deviation during simultaneous transmission can be adjusted by turning on the switch 52. Alternatively, the impedance may be adjusted in advance so that when the filters 31 and 32 are operated simultaneously, the impedance matching can be achieved when the switch 52 is in a non-conductive state. In this case, when only the filter 31 is operated, the impedance deviation during single transmission can be adjusted by turning on the switch 52.

[0109] As described above, the high frequency circuit 1C according to the present embodiment includes: the switch 51 having the selection terminals 51b and 51c; the switch 52; the filter 31 connected to the selection terminal 51b; the filter 32 connected to the selection terminal 51c; and the stub 80. The switch 52 is connected in series between the path connecting the selection terminal 51c and the filter 32 and the stub 80.

[0110] Thus, the impedance can be adjusted using the stub 80 , and thus the loss can be reduced.

[0111] In addition, the stub 80 may also function as a notch filter having a narrow stop band at a predetermined frequency by adjusting the line length. In addition, the stub 80 may be a short-circuited stub whose other end is connected to the ground.

[0112] (Implementation Method 2)

[0113] Next, embodiment 2 will be described.

[0114] The high frequency circuit according to the second embodiment is different from the first embodiment in that it includes a transmission filter. The following description will focus on the differences from the first embodiment, and the description of the common points will be omitted or simplified.

[0115] [2.1 Circuit Structure of High Frequency Circuit 201 and Communication Device 204]

[0116] First, use Figure 6 The circuit configurations of the high-frequency circuit 201 and the communication device 204 according to the second embodiment will be described. Figure 6 2 is a circuit configuration diagram of a high-frequency circuit 201 and a communication device 204 according to the present embodiment.

[0117] [2.1.1 Circuit Configuration of Communication Device 204]

[0118] First, the circuit structure of the communication device 204 is described. Figure 6 As shown, the communication device 204 involved in this embodiment includes a high-frequency circuit 201, an antenna 2, and an RF signal processing circuit (RFIC) 3. In addition, the communication device 204 includes a plurality of power amplifiers 11, 12, and 13, and a plurality of low-noise amplifiers 21 and 22. The antenna 2, the RFIC 3, and the low-noise amplifiers 21 and 22 are the same as those in the first embodiment.

[0119] The high frequency circuit 201 transmits a high frequency signal between the antenna 2 and the RFIC 3. In this embodiment, the high frequency circuit 201 transmits a reception signal as an example of a high frequency signal. In addition, the high frequency circuit 201 transmits a transmission signal as an example of a high frequency signal. The detailed structure of the high frequency circuit 201 will be described later.

[0120] The power amplifiers 11, 12, and 13 are examples of amplifiers that amplify high-frequency signals, respectively, and amplify the transmission signals and output them to the high-frequency circuit 201. The power amplifier 11 is connected to the high-frequency input terminal 111 of the high-frequency circuit 201, and the power amplifier 11 amplifies the transmission signal and inputs the amplified transmission signal to the high-frequency input terminal 111. The power amplifier 12 is connected to the high-frequency input terminal 112 of the high-frequency circuit 201, and the power amplifier 12 amplifies the transmission signal and inputs the amplified transmission signal to the high-frequency input terminal 112. The power amplifier 13 is connected to the high-frequency input terminal 113 of the high-frequency circuit 201, and the power amplifier 13 amplifies the transmission signal and inputs the amplified transmission signal to the high-frequency input terminal 113. The power amplifiers 11, 12, and 13 amplify transmission signals of different communication frequency bands, respectively. The power amplifiers 11, 12, and 13 can also be mounted on the same substrate as the high-frequency circuit 201 and modularized.

[0121] Figure 6 The circuit configuration of the communication device 204 shown in FIG. 2 is an example and is not limited thereto. For example, the communication device 204 may not include the antenna 2 . Alternatively, the communication device 204 may include a plurality of antennas 2 .

[0122] In addition, the communication device 204 may not include the power amplifiers 11, 12, and 13 and the low noise amplifiers 21 and 22. For example, the communication device 204 may include a low noise amplifier for amplifying received signals of multiple communication frequency bands. In addition, the communication device 204 may include a power amplifier for amplifying transmitted signals of multiple communication frequency bands.

[0123] [2.1.2 Circuit structure of high frequency circuit 201]

[0124] Next, the circuit configuration of the high-frequency circuit 201 according to the present embodiment will be described.

[0125] like Figure 6 As shown, the high frequency circuit 201 includes duplexers 61 and 62, a filter 63, switches 51 and 52, an antenna connection terminal 100, high frequency input terminals 111, 112 and 113, and high frequency output terminals 121 and 122. The antenna connection terminal 100, the high frequency output terminals 121 and 122, and the switches 51 and 52 are the same as those in the first embodiment.

[0126] The high-frequency input terminal 111 is connected to the RFIC 3 via the power amplifier 11. The high-frequency input terminal 111 is a terminal for receiving an input of a transmission signal amplified by the power amplifier 11.

[0127] The high-frequency input terminal 112 is connected to the RFIC 3 via the power amplifier 12 . The high-frequency input terminal 112 is a terminal for receiving an input of a transmission signal amplified by the power amplifier 12 .

[0128] The high-frequency input terminal 113 is connected to the RFIC 3 via the power amplifier 13. The high-frequency input terminal 113 is a terminal for receiving an input of a transmission signal amplified by the power amplifier 13.

[0129] The duplexers 61 and 62 are elements for demultiplexing transmission signals and reception signals, respectively. The passbands of the filters included in the duplexers 61 and 62 are different from each other.

[0130] The duplexer 61 includes a reception filter 61R and a transmission filter 61T.

[0131] The reception filter 61R is an example of a first filter, and has a passband including the first downlink operating frequency band. The input end of the reception filter 61R is connected to the selection terminal 51 b of the switch 51 . The output end of the reception filter 61R is connected to the high frequency output terminal 121 .

[0132] The transmission filter 61T is an example of a first transmission filter, and has a passband including a first uplink operating frequency band. The input end of the transmission filter 61T is connected to the high frequency input terminal 111. The output end of the transmission filter 61T is connected to the selection terminal 51b of the switch 51. In the present embodiment, the output end of the transmission filter 61T is connected to the selection terminal 51b after being commonized (bundled) with the input end of the reception filter 61R. There is no switch connected in series on the path connecting the input end of the reception filter 61R and the output end of the transmission filter 61T (the common terminal of the duplexer 61) with the selection terminal 51b.

[0133] The first downlink operating frequency band is, for example, the downlink operating frequency band of frequency band B1 or frequency band n1 (2110 MHz-2170 MHz). The first uplink operating frequency band is, for example, the uplink operating frequency band of frequency band B1 or frequency band n1 (1920 MHz-1980 MHz). In addition, the first downlink operating frequency band and the first uplink operating frequency band may also be included in different communication frequency bands.

[0134] The duplexer 62 includes a reception filter 62R and a transmission filter 62T.

[0135] The reception filter 62R is an example of a second filter, and has a passband including the second downlink operating frequency band. The input end of the reception filter 62R is connected to the selection terminal 51c of the switch 51. The output end of the reception filter 62R is connected to the high frequency output terminal 122.

[0136] The transmission filter 62T is an example of a second transmission filter, and has a passband including a second uplink operating frequency band. The input end of the transmission filter 62T is connected to the high frequency input terminal 112. The output end of the transmission filter 62T is connected to the selection terminal 51c of the switch 51. In the present embodiment, the output end of the transmission filter 62T is connected to the selection terminal 51c after being commonized (bundled) with the input end of the reception filter 62R. There is no switch connected in series on the path between the input end of the reception filter 62R and the output end of the transmission filter 62T (the common terminal of the duplexer 62) and the selection terminal 51c to connect the input end of the reception filter 62R and the output end of the transmission filter 62T to the selection terminal 51c.

[0137] The second downlink operating frequency band is a frequency band different from the first downlink operating frequency band. The second downlink operating frequency band is, for example, a downlink operating frequency band (1805MHz-1880MHz) of frequency band B3 or frequency band n3. The second uplink operating frequency band is a frequency band different from the first uplink operating frequency band. The second uplink operating frequency band is, for example, an uplink operating frequency band (1710MHz-1785MHz) of frequency band B3 or frequency band n3. In addition, the second downlink operating frequency band and the second uplink operating frequency band may also be included in different communication frequency bands.

[0138] The filter 63 is an example of a third filter and has a passband including a third frequency band. The input end of the filter 63 is connected to the high frequency input terminal 113. The output end of the filter 63 is connected to the selection terminal 51c of the switch 51 via the switch 52.

[0139] The third frequency band included in the passband of filter 63 is a frequency band different from the first uplink operating frequency band and the second uplink operating frequency band. For example, the third frequency band is a frequency band that does not overlap with the second uplink operating frequency band. In this embodiment, the third frequency band is a frequency band of SUL (Supplementary UpLink). The third frequency band is, for example, frequency band n81 (880MHz-915MHz), frequency band n82 (832MHz-862MHz), frequency band n83 (703MHz-748MHz), and frequency band n89 (824MHz-849MHz) used for 5G-NR.

[0140] [2.2 Action]

[0141] Next, refer to Figure 6 The operation of the high-frequency circuit 201 according to this embodiment will be described.

[0142] The high frequency circuit 201 has a single transmission mode and a simultaneous transmission mode.

[0143] In the single transmission mode, a high frequency signal of one communication frequency band is transmitted. Specifically, in the single transmission mode, by controlling switches 51 and 52, only one of the reception filter 61R, the transmission filter 61T, the reception filter 62R, and the transmission filter 62T is operated.

[0144] For example, the reception filter 61R or the transmission filter 61T is operated by connecting the common terminal 51a of the switch 51 to the selection terminal 51b. Also, the reception filter 62R or the transmission filter 62T is operated by connecting the common terminal 51a of the switch 51 to the selection terminal 51c and making the switch 52 non-conductive (off state).

[0145] In the present embodiment, the filter 63 is a filter including the SUL frequency band in the passband, and is a filter that operates auxiliary. Therefore, the filter 63 does not operate independently. That is, a single transmission is not performed only for the signal that passes through the filter 63. The signal that passes through the filter 63 is transmitted simultaneously with the signal that passes through the transmission filter 62T or the reception filter 62R. In other words, the filter 63 is used as an auxiliary to the transmission filter 62T or the reception filter 62R, and is a filter that does not operate independently.

[0146] In the simultaneous transmission mode, high frequency signals of multiple communication frequency bands are transmitted. Specifically, in the simultaneous transmission mode, by controlling switches 51 and 52, two or more filters among the reception filter 61R, the transmission filter 61T, the reception filter 62R, the transmission filter 62T, and the filter 63 are operated. In the high frequency circuit 201 involved in this embodiment, simultaneous reception, simultaneous transmission, and simultaneous transmission and reception of multiple communication frequency bands can be performed.

[0147] For example, by connecting the common terminal 51a of the switch 51 to the selection terminal 51b and making the switch 52 conductive (closed state), the two filters of the transmission filter 62T and the filter 63 are operated. In addition, when the switch 51 is a multi-connection type switch circuit, the common terminal 51a can be connected to both the selection terminals 51b and 51c. For example, by connecting the common terminal 51a of the switch 51 to the selection terminals 51b and 51c, respectively, and making the switch 52 non-conductive, the duplexers 61 and 62 are operated. In addition, by connecting the common terminal 51a of the switch 51 to the selection terminals 51b and 51c, respectively, and making the switch 52 conductive, the duplexers 61 and 62 and the filter 63 are operated.

[0148] [2.3 Effects, etc.]

[0149] As described above, in the high frequency circuit 201 involved in this embodiment, the receiving filter 61R has a passband including the first downlink operating frequency band. The receiving filter 62R has a passband including the second downlink operating frequency band different from the first downlink operating frequency band. The high frequency circuit 201 also includes: a transmitting filter 61T, one end of which is connected to the selection terminal 51b, and has a passband including the first uplink operating frequency band; and a transmitting filter 62T, one end of which is connected to the selection terminal 51c, and has a passband including the second uplink operating frequency band.

[0150] Thus, similarly to the high frequency circuit 1 according to the first embodiment, the filter 63 is connected to the selection terminal 51c via the switch 52, so that when only the duplexer 61 is operating, the disconnection capacitance of the switch 52 is not visible. Therefore, the signal leaking to the duplexer 62 and the filter 63 can be reduced, thereby reducing the loss. In addition, the high frequency circuit 201 includes a filter for transmission, so that high frequency signals can be transmitted and received.

[0151] In addition, for example, the filter 63 has a passband including the frequency band of SUL.

[0152] Thus, the filter 63 is a frequency band dedicated to the uplink and does not have a corresponding downlink operating frequency band. Therefore, it is not necessary to meet the attenuation requirement of the downlink operating frequency band that should be located nearby, so the filter design can be simplified. Therefore, the filter 63 can be miniaturized, which can contribute to the miniaturization of the high-frequency circuit 201.

[0153] In addition, for example, single transmission only for the signal that has passed through the filter 63 is not performed.

[0154] Thus, the filter 63 is not used in the single transmission mode, and therefore a dedicated selection terminal (eg, Figure 2 Therefore, the off capacitance when the filter 63 is not operated can be reduced, thereby reducing the loss.

[0155] In addition, for example, the signal that has passed through the filter 63 is transmitted simultaneously with the signal that has passed through the duplexer 62 (transmitting filter 62T).

[0156] This allows the duplexer 62 and the filter 63 to be connected to the same selection terminal 51c, thereby reducing the number of selection terminals of the switch 51. Therefore, the off capacitance when the filter 63 is not operated can be reduced, thereby reducing loss.

[0157] In addition, in the present embodiment, the communication frequency band included in the passband of each of the duplexers 61 and 62 is not particularly limited.

[0158] [2.4 Modifications]

[0159] Next, a modification of Embodiment 2 will be described. In the following description, the differences from Embodiment 2 will be mainly described, and the description of the common points will be omitted or simplified.

[0160] Figure 7 FIG. 2 is a circuit diagram of a high frequency circuit 201A according to a modification of the present embodiment. Figure 7 As shown, the high frequency circuit 201A and Figure 6 Compared with the high-frequency circuit 201 shown in the figure, a duplexer 73 is provided instead of the filter 63. In addition, the high-frequency circuit 201A includes a high-frequency output terminal 123.

[0161] The high frequency output terminal 123 is connected to the RFIC 3 (see Figure 6 The high frequency output terminal 123 is a terminal for outputting a reception signal received by the antenna 2 and transmitted in the high frequency circuit 201A to a low noise amplifier (not shown).

[0162] The duplexer 73 includes a reception filter 73R and a transmission filter 73T.

[0163] The reception filter 73R is an example of a third filter and has a passband including the third downlink operating frequency band. The input end of the reception filter 73R is connected to the selection terminal 51c of the switch 51 via the switch 52. The output end of the reception filter 73R is connected to the high frequency output terminal 123.

[0164] The transmission filter 73T is an example of a third transmission filter, and has a passband including a third uplink operating frequency band. The input end of the transmission filter 73T is connected to the high frequency input terminal 113. The output end of the transmission filter 73T is connected to the selection terminal 51c of the switch 51 via the switch 52. In the present embodiment, the output end of the transmission filter 73T is connected to the selection terminal 51c via the switch 52 after being commonized (bundled) with the input end of the reception filter 73R. There is no switch connected in series on the path between the input end of the reception filter 73R and the output end of the transmission filter 73T (the common terminal of the duplexer 73) and the switch 52 to connect the input end of the reception filter 73R and the output end of the transmission filter 73T to the switch 52.

[0165] The third downlink operating frequency band is a frequency band different from both the first downlink operating frequency band and the second downlink operating frequency band. In addition, the third uplink operating frequency band is a frequency band different from both the first uplink operating frequency band and the second uplink operating frequency band. For example, the third downlink operating frequency band and the third uplink operating frequency band are frequency bands that do not overlap with each other and do not overlap with both the second downlink operating frequency band and the second uplink operating frequency band. As the third downlink operating frequency band and the third uplink operating frequency band, frequency bands whose respective attenuation requirements are not located near each other, i.e., frequency bands with low design difficulty, can be used.

[0166] In this modification, in the single transmission mode, only one of the reception filter 73R and the transmission filter 73T may be operated. In other words, the reception filter 73R and the transmission filter 73T may be operated separately. For example, by connecting the common terminal 51a of the switch 51 to the selection terminal 51c and turning on the switch 52, the duplexer 73 becomes operable.

[0167] As described above, in the high frequency circuit 201A involved in this modification, the receiving filter 73R has a passband including the third downlink operating frequency band. The high frequency circuit 201A further includes a transmitting filter 73T, one end of which is connected to the terminal of the switch 52 located on the receiving filter 73R side, and the transmitting filter 73T includes the third uplink operating frequency band.

[0168] Thus, similarly to the high frequency circuit 1 according to the first embodiment, the duplexer 73 is connected to the selection terminal 51c via the switch 52, so that when only the duplexer 61 is operated, the disconnection capacitance of the switch 52 is not seen. Therefore, the number of signals leaking to the duplexers 62 and 73 can be reduced, thereby reducing the loss. In addition, the number of duplexers included in the high frequency circuit 201A increases, thereby increasing the types of signals that can be transmitted (communication frequency bands).

[0169] (Implementation 3)

[0170] Next, implementation mode 3 will be described.

[0171] The high frequency circuit according to the third embodiment is different from the first embodiment in that the antenna switch has a two-stage structure. The following description will focus on the differences from the first embodiment, and the description of the common points will be omitted or simplified.

[0172] [3.1 Circuit structure of high frequency circuit 301]

[0173] First, use Figure 8 A circuit configuration of a high-frequency circuit 301 according to the third embodiment will be described. Figure 83 is a circuit configuration diagram of a high-frequency circuit 301 according to the present embodiment.

[0174] like Figure 8 As shown, the high frequency circuit 301 includes filters 31, 32, 33, 35, 36, 37, 38, 39 and 40, switches 351, 52 and 353, an antenna connection terminal 100, high frequency output terminals 121, 122, 123, 125, 126, 127, 128, 129 and 130, and external connection terminals 150 and 160. The filters 31, 32 and 33, the antenna connection terminal 100, and the high frequency output terminals 121, 122 and 123 are the same as those in the first embodiment.

[0175] The high frequency output terminals 125, 126, 127, 128, 129 and 130 are connected to the RFIC 3 (see Figure 1 The high frequency output terminals 125, 126, 127, 128, 129 and 130 are terminals for outputting reception signals received by the antenna 2 and transmitted in the high frequency circuit 301 to a low noise amplifier (not shown).

[0176] The external connection terminal 150 is a high-frequency output terminal of the high-frequency circuit 301, and is a terminal for outputting the received signal received by the antenna 2 to the outside. For example, when the high-frequency circuit 301 is modularized on a substrate, the external connection terminal 150 is formed using a conductive member such as a bump electrode or a pad provided on the surface of the substrate. The external connection terminal 150 is connected to other receiving circuits (signal processing circuits) and the like outside the high-frequency circuit 301.

[0177] The external connection terminal 160 is a high-frequency input terminal of the high-frequency circuit 301, and is a terminal for receiving a transmission signal for transmission from the antenna 2 from the outside. For example, when the high-frequency circuit 301 is modularized on a substrate, the external connection terminal 160 is formed using a conductive member such as a bump electrode or a pad provided on the surface of the substrate. The external connection terminal 160 is connected to other transmission circuits (signal processing circuits) and the like outside the high-frequency circuit 301, for example.

[0178] The switches 351 and 353 constitute a two-stage antenna switch. Specifically, the common terminal 53a of the switch 353 is connected to the antenna connection terminal 100, and the common terminal 51a of the switch 351 is connected to one of the selection terminals (selection terminal 53e) of the switch 353.

[0179] The switch 351 is an example of a first switch, and has a common terminal 51a and selection terminals 51b, 51c, 51d, and 51e. The switch 351 switches between connection and non-connection of the common terminal 51a and the selection terminals 51b, 51c, 51d, and 51e. The common terminal 51a is connected to the selection terminal 53e of the switch 353. The selection terminal 51b is an example of a first selection terminal, and is connected to the filter 31. The selection terminal 51c is an example of a second selection terminal, and is connected to the filter 32 and the switch 52, respectively. The selection terminal 51d is an example of a first selection terminal, and is connected to the filters 35 and 36. The selection terminal 51e is an example of a first selection terminal, and is connected to the filter 37. The switch 351 is a SP4T (Single-Pole Four-Throw) type switch circuit. In addition, the switch 351 may also be a multi-connection type switch circuit. That is, the common terminal 51 a may be simultaneously connected to at least two of the selection terminals 51 b , 51 c , 51 d , and 51 e .

[0180] The switch 353 is an example of a third switch, and has a common terminal 53a and selection terminals 53b, 53c, 53d, 53e, 53f, and 53g. The switch 353 switches between connection and non-connection between the common terminal 53a and the selection terminals 53b, 53c, 53d, 53e, 53f, and 53g. The common terminal 53a is connected to the antenna connection terminal 100. The selection terminal 53b is an example of a third selection terminal, and is connected to the filter 38. The selection terminal 53c is an example of a third selection terminal, and is connected to the filter 39. The selection terminal 53d is an example of a third selection terminal, and is connected to the filter 40. The selection terminal 53e is an example of a fourth selection terminal, and is connected to the common terminal 51a of the switch 351. The selection terminal 53f is connected to the external connection terminal 150. The selection terminal 53g is connected to the external connection terminal 160. The switch 353 is a switch circuit of the SP6T (Single-Pole Six-Throw) type. The switch 353 may be a multi-connection type switch circuit, that is, the common terminal 53a may be simultaneously connected to at least two of the selection terminals 53b, 53c, 53d, 53e, 53f, and 53g.

[0181] The filters 35, 36, and 37 are each an example of a first filter, and have a passband that includes at least a part of a predetermined communication frequency band. The passbands of the filters are different from each other.

[0182] The passband of the filter 35 includes the TDD frequency band. The passband of the filter 35 includes, for example, the frequency band B34 (2010 MHz-2025 MHz) for LTE or the frequency band n34 (2010 MHz-2025 MHz) for 5G-NR.

[0183] The input end of the filter 35 is connected to the selection terminal 51d of the switch 351. The output end of the filter 35 is connected to the high-frequency output terminal 125.

[0184] The passband of the filter 36 includes the TDD frequency band. The passband of the filter 36 includes, for example, the frequency band B39 (1880 MHz-1920 MHz) for LTE or the frequency band n39 (1880 MHz-1920 MHz) for 5G-NR.

[0185] The input end of the filter 36 is connected to the selection terminal 51d of the switch 351. The output end of the filter 36 is connected to the high frequency output terminal 126. The filter 36 and the filter 35 together form a diplexer. That is, the input end of the filter 36 is common (bundled) with the input end of the filter 35 and connected to the selection terminal 51d of the switch 351. In addition, the switch 351 may also have selection terminals corresponding to the filters 35 and 36 respectively. There is no switch connected in series on the path between the filters 35 and 36 and the selection terminal 51d to connect the filters 35 and 36 and the selection terminal 51d.

[0186] The passband of the filter 37 includes at least a portion of the FDD (Frequency Division Duplex) frequency band. The passband of the filter 37 includes, for example, the downlink operating frequency band of the frequency band B66 (2110MHz-2200MHz) or the downlink operating frequency band of the frequency band B1 (2110MHz-2170MHz) for LTE, or the downlink operating frequency band of the frequency band n66 (2110MHz-2200MHz) or the downlink operating frequency band of the frequency band n1 (2110MHz-2170MHz) for 5G-NR.

[0187] The input end of the filter 37 is connected to the selection terminal 51e of the switch 351. The output end of the filter 37 is connected to the high-frequency output terminal 127. No switch is connected in series on the path between the filter 37 and the selection terminal 51e that connects the filter 37 and the selection terminal 51e.

[0188] In addition, in this embodiment, the passband of the filter 31 includes at least a portion of the FDD frequency band. The passband of the filter 31 includes, for example, the downlink operating frequency band (1930 MHz-1995 MHz) of the frequency band B25 for LTE or the downlink operating frequency band (1930 MHz-1995 MHz) of the frequency band n25 for 5G-NR.

[0189] Filter 32 includes the downlink operating frequency band (1805MHz-1880MHz) of frequency band B3 or frequency band n3 as in Embodiment 1. As in Embodiment 1, the passband of filter 33 includes the SDL frequency band. Specifically, the passband of filter 33 includes frequency band B32 (1452MHz-1496MHz) or frequency band n75 (1432MHz-1517MHz) or frequency band n76 (1427MHz-1432MHz).

[0190] Filters 38, 39, and 40 are examples of fifth filters, respectively, and have passbands that include at least a portion of a predetermined communication frequency band. The passbands of the filters are different from each other.

[0191] The passband of the filter 38 includes the TDD frequency band. The passband of the filter 38 includes, for example, the frequency band B40 (2300 MHz-2400 MHz) for LTE or the frequency band n40 (2300 MHz-2400 MHz) for 5G-NR.

[0192] The input end of the filter 38 is connected to the selection terminal 53b of the switch 353. The output end of the filter 38 is connected to the high-frequency output terminal 128. No switch is connected in series on the path between the filter 38 and the selection terminal 53b that connects the filter 38 and the selection terminal 53b.

[0193] The passband of the filter 39 includes the FDD frequency band. The passband of the filter 39 includes, for example, the downlink operating frequency band (2620 MHz-2690 MHz) of the frequency band B7 for LTE or the downlink operating frequency band (2620 MHz-2690 MHz) of the frequency band n7 for 5G-NR.

[0194] The input end of the filter 39 is connected to the selection terminal 53c of the switch 353. The output end of the filter 39 is connected to the high-frequency output terminal 129. No switch is connected in series on the path between the filter 39 and the selection terminal 53c that connects the filter 39 and the selection terminal 53c.

[0195] The passband of the filter 40 includes the TDD frequency band. The passband of the filter 40 includes, for example, the frequency band B41 (2496 MHz-2690 MHz) for LTE or the frequency band n41 (2496 MHz-2690 MHz) for 5G-NR.

[0196] The input end of the filter 40 is connected to the selection terminal 53d of the switch 353. The output end of the filter 40 is connected to the high-frequency output terminal 130. No switch is connected in series on the path between the filter 40 and the selection terminal 53d that connects the filter 40 and the selection terminal 53d.

[0197] In the present embodiment, the passband of each of the filters 38, 39 and 40 connected to the switch 353 of the first stage includes a frequency band with a higher frequency band than the passband of the filters 31, 32, 35, 36 and 37 connected to the switch 351 of the second stage. For example, the passband of each of the filters 38, 39 and 40 includes a frequency band above 2300MHz, which is called a high frequency band. In contrast, the passband of each of the filters 31, 32, 35, 36 and 37 includes a frequency band below 2300MHz, which is called a low frequency band, a medium frequency band or a medium-high frequency band. High-frequency signals with high frequency bands are greatly affected by the disconnection capacitance (parasitic capacitance) of the switch, and have a tendency to increase loss due to the disconnection capacitance. Therefore, by making the passband of each of the filters 38, 39 and 40 connected to the switch 353 of the first stage include a frequency band of the high frequency band, it is possible to reduce loss.

[0198] The structure of the high frequency circuit 301 is just an example and is not limited to the above. Figure 8 For example, the number of selection terminals of switches 351 and 353 can be 2 or more. The number, type, and passband of filters provided in high-frequency circuit 301 are not particularly limited. In addition, in high-frequency circuit 301, an example of a two-stage structure of switches 351 and 353 is shown, but it can also be composed of switches of three or more stages.

[0199] [3.2 Action]

[0200] Next, refer to Figure 8 The operation of the high-frequency circuit 301 according to this embodiment will be described.

[0201] The high frequency circuit 301 has a single transmission mode and a simultaneous transmission mode.

[0202] In the single transmission mode, a high frequency signal of one communication frequency band is transmitted. Specifically, in the single transmission mode, switches 351, 52 and 353 are controlled so that only one of filters 31, 32, 35, 36, 37, 38, 39 and 40 is operated.

[0203] For example, when only the filter 38 is operated, the common terminal 53a of the switch 353 is connected to the selection terminal 53b. Similarly, when only the filter 39 or 40 is operated, the common terminal 53a is connected to only one of the selection terminals 53c and 53d.

[0204] When the filter 31, 35, 36 or 37 is operated, the common terminal 53a of the switch 353 is connected to the selection terminal 53e, and the common terminal 51a of the switch 351 is connected to any one of the selection terminals 51b, 51d and 51e. When only the filter 32 is operated, the common terminal 53a of the switch 353 is connected to the selection terminal 53e, the common terminal 51a of the switch 351 is connected to the selection terminal 51c, and the switch 52 is made non-conductive.

[0205] In this embodiment, similarly to Embodiment 1, the filter 33 does not operate independently. That is, a single transmission is not performed only for the signal that has passed through the filter 33. The signal that has passed through the filter 33 is transmitted simultaneously with the signal that has passed through the filter 32.

[0206] In the simultaneous transmission mode, high frequency signals of multiple communication frequency bands are transmitted. Specifically, in the simultaneous transmission mode, switches 351, 52 and 353 are controlled to operate two or more filters among filters 31, 32, 33, 35, 36, 37, 38, 39 and 40.

[0207] For example, by connecting the common terminal 53a of the switch 353 to the selection terminal 53e, connecting the common terminal 51a of the switch 351 to the selection terminal 51c, and turning on the switch 52, the two filters 32 and 33 are operated. In addition, the switches 351 and 353 may be multi-connection type switches, respectively. In this case, any two or more filters among the filters 31, 32, 33, 35, 36, 37, 38, 39 and 40 can be transmitted simultaneously.

[0208] [3.3 Effects, etc.]

[0209] As described above, in the high frequency circuit 301 involved in this embodiment, the switch 351 has a common terminal 51a, and the switch 351 can switch the connection between the common terminal 51a and the selection terminal 51b and the connection between the common terminal 51a and the selection terminal 51c. The high frequency circuit 301 also includes: a switch 353, which has a selection terminal 53d and a selection terminal 53e; and a filter 40, which is connected to the selection terminal 53d. The common terminal 51a is connected to the selection terminal 53e.

[0210] Thus, similarly to the high frequency circuit 1 according to the first embodiment, the filter 33 is connected to the selection terminal 51c via the switch 52, so that the disconnection capacitance of the switch 52 is not seen when the filter 31, 35, 36 or 37 operates in the single transmission mode. Therefore, the signal leaking to the filters 32 and 33 can be reduced, thereby reducing the loss. In addition, the switch 351 and the switch 353 are connected in a two-stage structure, so that the disconnection capacitance of the filter 38, 39 or 40 connected to the first-stage switch 353 when operating in the single transmission mode can be made smaller. That is, compared with the case where a large number of selection terminals are provided in one switch 353, the disconnection capacitance can be made smaller, so that the loss can be reduced.

[0211] [3.4 Modifications]

[0212] Next, a modification of Embodiment 3 will be described. In the following description, differences from Embodiment 3 will be mainly described, and description of common points will be omitted or simplified.

[0213] Fig. 9 FIG. 1 is a circuit diagram of a high frequency circuit 301A according to a modification of the present embodiment. Fig. 9 As shown, the high frequency circuit 301A and Figure 8 Compared with the high frequency circuit 301 shown in the figure, a switch 351A is provided in place of the switch 351. In addition, the high frequency circuit 301A is provided with a switch 354.

[0214] The switch 351A is similar to the switch 351A except that the number of selection terminals is small. Figure 8 Specifically, switch 351A does not have selection terminal 51d. Figure 8 The filters 35 and 36 connected to the selection terminal 51 d are examples of sixth filters, respectively, and are connected to the selection terminal 53 d of the switch 353 via the switch 354 .

[0215] The switch 354 is an example of a fourth switch. The switch 354 is connected in series between the path connecting the selection terminal 53d of the switch 353 and the filter 40 and the filters 35 and 36. Specifically, the switch 354 is connected in series between the node N3 located on the path connecting the selection terminal 53d and the filter 40 and the filters 35 and 36. In addition, the node N3 may also be consistent with the selection terminal 53d or the input end of the filter 40. The switch 354 can switch the connection and non-connection between the selection terminal 53d (node ​​N3) and the filters 35 and 36. The switch 354 is a SPST type switch circuit.

[0216] As described above, the high frequency circuit 301A according to the present modification further includes the switch 354 and the filter 35 or 36. The switch 354 is connected in series between the path connecting the selection terminal 53d and the filter 40 and the filter 35 or 36.

[0217] Thus, the first-stage switch 353 is also connected to the filters 35 and 36 at its selection terminal 53d via the switch 354. Therefore, when the filter 38 or 39 operates in the single transmission mode, the disconnection capacitance of the switch 354 is not visible. Therefore, the signal leaking to the filters 40, 35, and 36 can be reduced, and the loss can be reduced. In addition, the number of selection terminals of the switch 351A is small, so the disconnection capacitance of the switch 351A can be reduced. Therefore, the loss can be reduced.

[0218] (other)

[0219] As mentioned above, the high-frequency circuit and the communication device according to the present invention have been described based on the above-mentioned embodiments and the like, but the present invention is not limited to the above-mentioned embodiments.

[0220] For example, in the above-mentioned embodiments 1 and 3 and each modified example, an example in which a high-frequency circuit transmits a reception signal is shown, but a transmission signal may also be transmitted. Figure 1 The filters 31, 32 and 33 shown may also all include the uplink operating frequency band of the communication frequency band in the passband. That is, the high frequency circuit may not transmit the received signal.

[0221] Next, features of the high-frequency circuit and the communication device described in the above-mentioned embodiments are shown.

[0222] <1>

[0223] A high frequency circuit having:

[0224] a first switch having a first selection terminal and a second selection terminal;

[0225] Second switch;

[0226] a first filter connected to the first selection terminal;

[0227] a second filter connected to the second selection terminal; and

[0228] The third filter,

[0229] The second switch is connected in series between a path connecting the second selection terminal and the second filter and the third filter.

[0230] <2>

[0231] according to <1> The high frequency circuit, wherein:

[0232] The third filter has a passband including a frequency band of a supplemental downlink, ie, SDL.

[0233] <3>

[0234] according to <1> or <2> The high frequency circuit, wherein:

[0235] The first switch has a common terminal, and the first switch can switch between connection between the common terminal and the first selection terminal and connection between the common terminal and the second selection terminal.

[0236] The high-frequency circuit is configured such that when the common terminal is connected to the second selection terminal, the second switch is turned on.

[0237] <4>

[0238] according to <1> ~ <3> A high frequency circuit as described in any one of claims , wherein:

[0239] A fourth filter is further provided, one end of which is connected to a path connecting the second switch and the third filter.

[0240] <5>

[0241] according to <1> The high frequency circuit, wherein:

[0242] The first filter has a passband including a first downlink operating frequency band,

[0243] The second filter has a passband including a second downlink operating frequency band, the second downlink operating frequency band being different from the first downlink operating frequency band,

[0244] The high frequency circuit further comprises:

[0245] a first transmission filter, one end of which is connected to the first selection terminal and has a passband including a first uplink operating frequency band; and

[0246] The second transmission filter has one end connected to the second selection terminal and has a passband including a second uplink operating frequency band.

[0247] <6>

[0248] according to <5> The high frequency circuit, wherein:

[0249] The third filter has a passband including a frequency band of a supplementary uplink, or SUL.

[0250] <7>

[0251] according to <5> The high frequency circuit, wherein:

[0252] The third filter has a passband including a third downlink operating frequency band,

[0253] The high frequency circuit further includes a third transmission filter, one end of which is connected to a terminal of the second switch on the second filter side, and the third transmission filter includes a third uplink operating frequency band.

[0254] <8>

[0255] according to <1> ~ <7> A high frequency circuit as described in any one of claims , wherein:

[0256] The first switch has a common terminal, and the first switch can switch between connection between the common terminal and the first selection terminal and connection between the common terminal and the second selection terminal.

[0257] The high frequency circuit further comprises:

[0258] a third switch having a third selection terminal and a fourth selection terminal; and

[0259] a fifth filter connected to the third selection terminal,

[0260] The common terminal is connected to the fourth selection terminal.

[0261] <9>

[0262] according to <8> The high frequency circuit, wherein:

[0263] The high frequency circuit further comprises a fourth switch and a sixth filter,

[0264] The fourth switch is connected in series between a path connecting the third selection terminal and the fifth filter and the sixth filter.

[0265] <10>

[0266] according to <1> ~ <9> A high frequency circuit as described in any one of claims , wherein:

[0267] The third filter is an auxiliary filter of the second filter.

[0268] <11>

[0269] A high frequency circuit having:

[0270] a first switch having a first selection terminal and a second selection terminal;

[0271] Second switch;

[0272] a first filter connected to the first selection terminal;

[0273] a second filter connected to the second selection terminal; and

[0274] External connection terminals,

[0275] The second switch is connected in series between a path connecting the second selection terminal and the second filter and the external connection terminal.

[0276] <12>

[0277] A high frequency circuit having:

[0278] a first switch having a first selection terminal and a second selection terminal;

[0279] The second switch is a single-pole single-throw, or SPST, type;

[0280] a first filter connected to the first selection terminal;

[0281] a second filter connected to the second selection terminal; and

[0282] The third filter,

[0283] wherein the second switch is connected in series between a path connecting the second selection terminal and the second filter and the third filter,

[0284] The third filter has a passband including a frequency band of a supplemental downlink, ie, SDL.

[0285] <13>

[0286] A communication device, comprising:

[0287] according to <1> ~ <12> The high frequency circuit described in any one of the above; and

[0288] The radio frequency signal processing circuit is an RF signal processing circuit, which processes the high frequency signal transmitted in the high frequency circuit.

[0289] In addition, the present invention may also include various modifications that can be conceived by those skilled in the art to the various embodiments, and various embodiments that can be achieved by arbitrarily combining the structural elements and functions in the various embodiments without departing from the spirit of the present invention.

[0290] Industrial Applicability

[0291] The present invention can be widely used in communication devices such as mobile phones as a front-end circuit supporting multi-band / multi-mode.

[0292] Description of Reference Numerals

[0293] 1, 1A, 1B, 1C, 201, 201A, 301, 301A: high frequency circuit; 2: antenna; 3: RFIC; 4, 204: communication device; 11, 12, 13: power amplifier; 21, 22, 23: low noise amplifier; 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 63: filter; 51, 52, 351, 351A, 353, 354: switch; 51a, 53a: common terminal; 51b, 51c, 51d, 51e, 53b, 53 c, 53d, 53e, 53f, 53g: selection terminal; 61, 62, 73: duplexer; 61R, 62R, 73R: receiving filter; 61T, 62T, 73T: transmitting filter; 80: stub; 100: antenna connection terminal; 111, 112, 113: high-frequency input terminal; 121, 122, 123, 124, 125, 126, 127, 128, 129, 130: high-frequency output terminal; 140, 150, 160: external connection terminal; N1, N2, N3: node.

Claims

1. A high frequency circuit having: a first switch having a first selection terminal and a second selection terminal; Second switch; a first filter connected to the first selection terminal; a second filter connected to the second selection terminal; as well as The third filter, The second switch is connected in series between a path connecting the second selection terminal and the second filter and the third filter.

2. The high frequency circuit according to claim 1, wherein: The third filter has a passband including a frequency band of a supplemental downlink, ie, SDL.

3. The high frequency circuit according to claim 1 or 2, wherein: The first switch has a common terminal, and the first switch can switch between connection between the common terminal and the first selection terminal and connection between the common terminal and the second selection terminal. The high-frequency circuit is configured such that when the common terminal is connected to the second selection terminal, the second switch is turned on.

4. The high frequency circuit according to any one of claims 1 to 3, wherein: A fourth filter is further provided, one end of which is connected to a path connecting the second switch and the third filter.

5. The high frequency circuit according to claim 1, wherein: The first filter has a passband including a first downlink operating frequency band, The second filter has a passband including a second downlink operating frequency band, the second downlink operating frequency band being different from the first downlink operating frequency band, The high frequency circuit further comprises: a first transmission filter, one end of which is connected to the first selection terminal and has a passband including a first uplink operating frequency band; and The second transmission filter has one end connected to the second selection terminal and has a passband including a second uplink operating frequency band.

6. The high frequency circuit according to claim 5, wherein: The third filter has a passband including a frequency band of a supplementary uplink, or SUL.

7. The high frequency circuit according to claim 5, wherein: The third filter has a passband including a third downlink operating frequency band, The high frequency circuit further includes a third transmission filter, one end of which is connected to a terminal of the second switch on the second filter side, and the third transmission filter includes a third uplink operating frequency band.

8. The high frequency circuit according to any one of claims 1 to 7, wherein: The first switch has a common terminal, and the first switch can switch between connection between the common terminal and the first selection terminal and connection between the common terminal and the second selection terminal. The high frequency circuit further comprises: a third switch having a third selection terminal and a fourth selection terminal; and a fifth filter connected to the third selection terminal, The common terminal is connected to the fourth selection terminal.

9. The high frequency circuit according to claim 8, wherein: The high frequency circuit further comprises a fourth switch and a sixth filter, The fourth switch is connected in series between a path connecting the third selection terminal and the fifth filter and the sixth filter.

10. The high frequency circuit according to any one of claims 1 to 9, wherein: The third filter is an auxiliary filter of the second filter.

11. A high frequency circuit comprising: a first switch having a first selection terminal and a second selection terminal; Second switch; a first filter connected to the first selection terminal; a second filter connected to the second selection terminal; and External connection terminals, The second switch is connected in series between a path connecting the second selection terminal and the second filter and the external connection terminal.

12. A high frequency circuit comprising: a first switch having a first selection terminal and a second selection terminal; The second switch is a single-pole single-throw, or SPST, type; a first filter connected to the first selection terminal; a second filter connected to the second selection terminal; as well as The third filter, wherein the second switch is connected in series between a path connecting the second selection terminal and the second filter and the third filter, The third filter has a passband including a frequency band of a supplemental downlink, ie, SDL.

13. A communication device comprising: The high frequency circuit according to any one of claims 1 to 12; and The radio frequency signal processing circuit is an RF signal processing circuit, which processes the high frequency signal transmitted in the high frequency circuit.

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