阅读说明：本技术 高频模块和通信装置 (High-frequency module and communication device ) 是由 松本翔 于 2019-04-02 设计创作，主要内容包括：高频模块(1)具备：开关电路(20),其具有发送用端子(22a)、接收用端子(22b)、选择端子(22c)以及公共端子(21a),能够对(A)发送用端子(22a)与公共端子(21a)的连接、(B)发送用端子(22a)及选择端子(22c)与公共端子(21a)的连接、(C)接收用端子(22b)及选择端子(22c)与公共端子(21a)的连接、(D)接收用端子(22b)与公共端子(21a)的连接进行切换；发送接收滤波器(11),其与公共端子(21a)连接,以通信频段A的发送接收带为通带,应用于时分双工方式；以及DTC(23),其与选择端子(22c)连接,该DTC(23)的电容值能够与开关电路(20)对连接的切换对应地变化。(A high-frequency module (1) is provided with: a switch circuit (20) having a transmission terminal (22a), a reception terminal (22B), a selection terminal (22C), and a common terminal (21a), and capable of switching (A) connection between the transmission terminal (22a) and the common terminal (21a), (B) connection between the transmission terminal (22a) and the selection terminal (22C) and the common terminal (21a), (C) connection between the reception terminal (22B) and the selection terminal (22C) and the common terminal (21a), and (D) connection between the reception terminal (22B) and the common terminal (21 a); a transmission/reception filter (11) connected to the common terminal (21a), having a transmission/reception band of the communication band A as a pass band, and applied to a time division duplex system; and a DTC (23) connected to the selection terminal (22c), wherein the capacitance value of the DTC (23) can be changed in accordance with the switching of the connection by the switch circuit (20).)

1. A high-frequency module is provided with:

a switch circuit having a transmission terminal for inputting a high-frequency transmission signal, a reception terminal for outputting a high-frequency reception signal, a first selection terminal, and a first common terminal, and capable of switching (1) connection between the transmission terminal and the first common terminal, (2) connection between the transmission terminal and the first selection terminal and the first common terminal, (3) connection between the reception terminal and the first selection terminal and the first common terminal, and (4) connection between the reception terminal and the first common terminal;

a first filter connected to the first common terminal, having a transmission/reception band of a first communication band as a passband, and applied to a time division duplex system; and

and a variable impedance element connected to the first selection terminal, wherein an impedance of the variable impedance element is variable in accordance with switching of connection of the switching circuit.

2. The high-frequency module as claimed in claim 1,

the switching circuit and the variable impedance element are formed as 1 chip.

3. The high-frequency module according to claim 1 or 2,

the variable impedance element is a DTC, i.e. a digital tunable capacitor.

4. The high-frequency module according to any one of claims 1 to 3, further comprising:

a transmission power amplifier having an input terminal and an output terminal, the output terminal being connected to the transmission terminal, the transmission power amplifier operating in any one of a first transmission mode that gives priority to power efficiency and a second transmission mode that gives priority to the magnitude of output power; and

and a reception low noise amplifier having an input terminal and an output terminal, wherein the input terminal is connected to the reception terminal.

5. The high-frequency module as claimed in claim 4,

in the case of the switching circuit described above,

(1) when the transmission terminal and the first common terminal are connected, the impedance of the first filter when the first filter is viewed from the first common terminal is matched to the optimum impedance of the first transmission mode,

(2) when the transmission terminal and the first selection terminal are connected to the first common terminal, the variable impedance element is set to a first impedance value, and the impedance of the first filter when viewed from the first common terminal to the first filter is matched to the impedance of the second transmission mode,

(3) when the reception terminal and the first selection terminal are connected to the first common terminal, the variable impedance element is set to a second impedance value, and the impedance of the first filter when viewed from the first common terminal toward the first filter matches the impedance of the reception low noise amplifier when viewed from the first common terminal toward the reception low noise amplifier.

6. The high-frequency module according to claim 5,

the switch circuit further has a second common terminal and a second selection terminal to which a high-frequency signal of a second communication band is input or output,

the high-frequency module further includes a second filter connected to the second common terminal and having a second communication band as a passband.

In the switch circuit, the variable impedance element is set to a third impedance value in a case where any one of the following connections and the connection of the second common terminal and the second selection terminal are simultaneously performed: (1) the connection between the transmission terminal and the first common terminal, (2) the connection between the transmission terminal and the first selection terminal and the first common terminal, and (3) the connection between the reception terminal and the first selection terminal and the first common terminal.

7. A communication device is provided with:

a radio frequency signal processing circuit that processes a high frequency signal transmitted and received by the antenna element;

the high frequency module according to any one of claims 1 to 6, which transfers the high frequency signal between the antenna element and the radio frequency signal processing circuit; and

and a control unit that controls connection of the switching circuit.

Technical Field

The present invention relates to a high-frequency module and a communication apparatus.

Background

In mobile communication devices such as mobile phones, particularly, with the progress of multi-band communication, it is required to transmit and receive high-frequency signals with low loss in each of a plurality of communication bands.

Patent document 1 discloses an adjustable matching network including: a T/R switch connected to the antenna and switching between a transmission path (T) and a reception path (R); a variable receive matching network connected to the receive contact of the T/R switch; and a variable transmission matching network connected with the transmission contact of the T/R switch. Thus, the impedance of the filter connected to the variable reception matching network or the variable transmission matching network can be automatically matched with the impedance of the antenna in accordance with the selection of the communication band.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication No. 2004-519150

Disclosure of Invention

Problems to be solved by the invention

According to the adjustable matching network described in patent document 1, impedance matching between the antenna and the filter can be achieved in accordance with selection of the transmission path and the reception path by the time division duplex method.

However, according to the adjustable matching network described in patent document 1, it is not possible to adjust the impedance of the input (transmission circuit) side of the filter in accordance with a plurality of transmission modes of the transmission circuit that inputs the high-frequency signal to the filter. That is, it is difficult to achieve both impedance matching between the antenna and the filter in both the transmission state and the reception state and impedance matching between the filter and the transmission circuit in a plurality of different transmission modes.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a high-frequency module and a communication apparatus capable of achieving both impedance adjustment between a transmission mode and a reception mode and impedance adjustment between different transmission modes in a transmission/reception path in which a filter to which a time division duplex method is applied is disposed.

Means for solving the problems

In order to achieve the above object, a high-frequency module according to an aspect of the present invention includes: a switch circuit having a transmission terminal for inputting a high-frequency transmission signal, a reception terminal for outputting a high-frequency reception signal, a first selection terminal, and a first common terminal, and capable of switching (1) connection between the transmission terminal and the first common terminal, (2) connection between the transmission terminal and the first selection terminal and the first common terminal, (3) connection between the reception terminal and the first selection terminal and the first common terminal, and (4) connection between the reception terminal and the first common terminal; a first filter connected to the first common terminal, having a transmission/reception band of a first communication band as a passband, and applied to a time division duplex system; and a variable impedance element connected to the first selection terminal, wherein an impedance of the variable impedance element is variable in accordance with switching of connection of the switching circuit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a high-frequency module and a communication device capable of achieving both impedance adjustment between a transmission mode and a reception mode and impedance adjustment between different transmission modes in a transmission/reception path in which a filter to which a time division duplex method is applied is arranged.

Drawings

Fig. 1 is a circuit configuration diagram of a communication device according to an embodiment.

Fig. 2 is a circuit diagram showing a connection state of the switch circuit in each mode of the high-frequency module according to the embodiment.

Fig. 3 is a smith chart showing the impedance of the high-frequency module according to the comparative example.

Fig. 4 is a smith chart showing the impedance of the high-frequency module according to the embodiment in the first transmission mode.

Fig. 5 is a smith chart showing the impedance of the high-frequency module according to the embodiment in the reception mode.

Fig. 6 is a smith chart showing the optimum impedance of the high-frequency module according to the embodiment in the first transmission mode and the second transmission mode.

Fig. 7 is a circuit diagram showing a connection state of the switch circuit according to the combination of CA in the high-frequency module according to the modification of the embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments and modifications described below are all examples in general or specific. The numerical values, shapes, materials, constituent elements, arrangement of constituent elements, connection modes, and the like shown in the following examples and modifications are merely examples, and the gist thereof is not limited to the invention. Of the components of the following examples and modifications, components not described in the independent claims will be described as arbitrary components. The sizes of the components shown in the drawings and the ratio of the sizes are not necessarily strict.

(embodiment mode)

[1 Structure of communication device ]

Fig. 1 is a circuit configuration diagram of a communication device 4 according to the embodiment. As shown in the drawing, the communication device 4 includes a high-Frequency module 1, an antenna element 2, and an RF (Radio Frequency) signal processing circuit (RFIC) 3.

The RFIC 3 is an RF signal processing circuit that processes high-frequency signals transmitted and received by the antenna element 2. Specifically, the RFIC 3 performs signal processing on the high-frequency reception signal input through the reception path of the high-frequency module 1 by down-conversion or the like, and outputs the reception signal generated by the signal processing to a baseband signal processing circuit (not shown) or the like. The RFIC 3 performs signal processing such as up-conversion on a transmission signal input from a baseband signal processing circuit or the like, and outputs a high-frequency transmission signal generated by the signal processing to a transmission path of the high-frequency module 1.

The RFIC 3 also has a function as a control unit that controls the connection state of the switch circuits 20 and 30 included in the high-frequency module 1 based on (1) selection of a communication band and (2) selection of a transmission mode and a reception mode. Specifically, RFIC 3 switches the connection state of switch circuit 20 by control signal S1, and switches the connection state of switch circuit 30 by control signal S2. The control unit may be provided outside the RFIC 3, for example, the high frequency module 1, the baseband signal processing circuit, or the like.

The antenna element 2 is connected to the antenna connection terminal 100 of the high-frequency module 1, radiates a high-frequency signal output from the high-frequency module 1, receives a high-frequency signal from the outside, and outputs the high-frequency signal to the high-frequency module 1.

In the communication device 4 according to the present embodiment, the antenna element 2 is not an essential component.

Next, the detailed structure of the high-frequency module 1 will be described.

As shown in fig. 1, the high-frequency module 1 includes: an antenna connection terminal 100, switching circuits 20 and 30, a DTC (Digital Tunable Capacitor) 23, transmission and reception filters 11 and 12, a transmission filter 13, a reception filter 14, a transmission power amplifier 41, and a reception low noise amplifier 42.

The antenna connection terminal 100 is connected to the antenna element 2.

The transmission/reception filter 11 is a first filter that uses a Time Division Duplex (TDD) scheme corresponding to switching of the connection of the switch circuit 20, with the transmission/reception band of the communication band a as a passband. The transmission/reception filter 12 is a filter that uses a time division duplex scheme corresponding to switching of the pair of switching circuits 20, with the transmission/reception band of the communication band B as a passband. The transmission filter 13 is a filter having a transmission band of the communication band C as a passband. The reception filter 14 is a filter having a reception band of the communication band C as a passband. The transmission filter 13 and the reception filter 14 constitute a duplexer for transmitting and receiving a high-Frequency signal in the communication band C by Frequency Division Duplex (FDD).

The transmission power amplifier 41 has an input terminal connected to the RFIC 3 and an output terminal, and the transmission power amplifier 41 amplifies the high-frequency transmission signal of the communication band A, B and C.

The reception low noise amplifier 42 has an input terminal and an output terminal, and the output terminal is connected to the RFIC 3, and the reception low noise amplifier 42 amplifies the high frequency reception signal of the communication bands A, B and C.

The switch circuit 20 has common terminals 21a, 21b, 21c, 21d, a transmission terminal 22a, a reception terminal 22b, and a selection terminal 22 c. The common terminal 21a (first common terminal) is connected to the transmission/reception filter 11. The common terminal 21b is connected to the transmission/reception filter 12. The common terminal 21c is connected to the transmission filter 13. The common terminal 21d is connected to the reception filter 14. The transmission terminal 22a is connected to an output terminal of the transmission power amplifier 41. The receiving terminal 22b is connected to an input terminal of the receiving low noise amplifier 42. The selection terminal 22c (first selection terminal) is connected to the DTC 23.

The DTC23 is connected to a path connecting the selection terminal 22c to ground. The DTC23 is a capacitor whose capacitance value can be changed stepwise in accordance with switching of the connection of the switching circuit 20. Further, the control unit described above switches the capacitance value of the DTC 23.

The DTC23 may not be a variable capacitor, but may be a variable impedance element whose impedance can be changed in accordance with switching of the connection of the switching circuit 20.

Further, by applying the DTC23 as the variable impedance element, the variable impedance element can be realized by a small element having a plurality of capacitance values, and therefore, the impedance of the high-frequency module 1 can be adjusted with high accuracy, and the high-frequency module 1 can be downsized.

Further, a circuit for adjusting impedance may be arranged between each common terminal of the switch circuit 20 and the filter. Further, a circuit for adjusting impedance may be disposed between the transmission terminal 22a of the switch circuit 20 and the transmission power amplifier 41. Further, a circuit for adjusting impedance may be disposed between the reception terminal 22b of the switch circuit 20 and the reception low-noise amplifier 42.

The switch circuit 30 has a common terminal 31a, selection terminals 32a, 32b, and 32 c. The common terminal 31a is connected to the antenna connection terminal 100, the selection terminal 32a is connected to the transmission/reception filter 11, the selection terminal 32b is connected to the transmission/reception filter 12, and the selection terminal 32c is connected to the transmission filter 13 and the reception filter 14. With this connection configuration, the switch circuit 30 switches (a) the connection between the antenna element 2 and the transmission/reception filter 11, (b) the connection between the antenna element 2 and the transmission/reception filter 12, and (c) the connection between the antenna element 2 and the transmission filter 13 and the reception filter 14. The switch circuit 30 is a multi-connection type switch circuit capable of simultaneously performing 2 or more connections among the above-described (a), (b), and (c). That is, the high-frequency module 1 according to the present embodiment can simultaneously transmit, receive, or transmit/receive high-frequency signals of at least 2 communication bands among the 3 communication bands, in addition to transmitting/receiving high-frequency signals of only one of the communication bands a, B, and C.

In the above configuration of the high-frequency module 1, the filter may be provided with the transmission/reception filter 11, or may be omitted from the transmission/reception filter 12, the transmission filter 13, and the reception filter 14. In response to this, the common terminals 21b and 21d of the switch circuit 20 and the switch circuit 30 are not essential components. In this case, the high frequency module 1 can transmit, receive, or transmit and receive only the high frequency signal of the communication band a. Further, the transmission power amplifier 41 and the reception low noise amplifier 42 may be incorporated in the RFIC 3, for example, and in this case, the high frequency module 1 may not include the transmission power amplifier 41 and the reception low noise amplifier 42.

In the high-frequency module 1 having the above-described configuration, the switch circuit 20 switches the connection of (1) the connection of the transmission terminal 22a and the common terminal 21a, (2) the connection of the transmission terminal 22a and the common terminal 21a and the connection of the selection terminal 22c and the common terminal 21a, (3) the connection of the reception terminal 22b and the common terminal 21a and the connection of the selection terminal 22c and the common terminal 21a, and (4) the connection of the reception terminal 22b and the common terminal 21 a. That is, the switch circuit 20 is a multi-connection type switch circuit capable of realizing at least the connection states (1) to (4) described above.

The DTC23 is set to a first capacitance value (first impedance value) in the connection state of (2) above, and is set to a second capacitance value (second impedance value) in the connection state of (3) above.

According to the above configuration of the high-frequency module 1 according to the present embodiment, by setting the switch circuit 20 to the connection state of (1) or the connection state of (2), the high-frequency module 1 is set to the transmission mode in which the high-frequency transmission signal is input to the transmission/reception filter 11 via the transmission terminal 22a and the common terminal 21 a. In addition, by setting the switch circuit 20 to the connection state of the above-mentioned (3) or the connection state of the above-mentioned (4), the high frequency module 1 is set to the reception mode in which the high frequency reception signal from the transmission/reception filter 11 is output from the reception terminal 22b via the common terminal 21 a. That is, the high frequency module 1 can be set to the transmission mode or the reception mode by switching between the connection state of (1) or (2) and the connection state of (3) or (4) by the switch circuit 20. At this time, the following is assumed: the impedance of the transmission circuit connected to the transmission terminal 22a as viewed from the transmission terminal 22a is different from the impedance of the reception circuit connected to the reception terminal 22b as viewed from the reception terminal 22 b. In this case as well, since the DTC23 is connected to the common terminal 21a by the connection state of (3) above, the impedance matching between the reception circuit and the transmission/reception filter 11 in the reception mode can be made to be the same as the impedance matching between the transmission circuit and the transmission/reception filter 11 in the transmission mode.

Also, the following is assumed: the transmission circuit connected to the transmission terminal 22a has, for example, a first transmission mode in which the efficiency of transmission power is emphasized and a second transmission mode in which the magnitude of transmission power is emphasized. In this case, the optimum impedance of the transmission circuit in the first transmission mode is different from the optimum impedance of the transmission circuit in the second transmission mode. Even in this case, in (2) above, the DTC23 is connected to the common terminal 21a, and the capacitance value (first capacitance value) of the DTC23 can be made different from the impedance value (second capacitance value) of the DTC23 in (3) above. This improves both the impedance matching between the transmission circuit and the transmission/reception filter 11 in the first transmission mode and the impedance matching between the transmission circuit and the transmission/reception filter 11 in the second transmission mode.

As described above, in the high-frequency module 1 in which the transmission/reception path to which the transmission/reception filter 11 of the Time Division Duplex (TDD) system is applied is shared, it is possible to achieve both the impedance adjustment between the transmission mode and the reception mode and the impedance adjustment between the different transmission modes (the first transmission mode and the second transmission mode).

Further, the switch circuit 20 and the DTC23 may be formed as 1 chip. Thus, since the wiring connecting the DTC23 and the selection terminal 22c can be made short, the impedance of the high-frequency module 1 can be adjusted with high accuracy by changing the capacitance of the DTC 23. In addition, the high-frequency module 1 can be miniaturized.

The switching circuit 20, DTC23, and the control unit may constitute 1 switching IC. This can shorten the control wiring connecting the control unit to the switch circuit 20 and the DTC23, and thus can suppress the control signal from interfering with the high-frequency signal and reduce the control accuracy. Further, the high-frequency module 1 can be manufactured at low cost by configuring the switch IC with a Si-based CMOS (Complementary Metal Oxide Semiconductor).

[2 Effect of high frequency Module ]

Next, the operational effects of the high-frequency module 1 according to the present embodiment will be described in detail.

Fig. 2 is a circuit diagram showing a connection state of the switch circuit 20 in the reception mode, the first transmission mode, and the second transmission mode of the high-frequency module 1 according to the embodiment. The connection structure of the switch circuit 20, the transmission/reception filter 11, the transmission power amplifier 41, and the reception low noise amplifier 42 in the high frequency module 1 according to the present embodiment is disclosed in the drawing. The circuit connection structure in the reception mode of the communication band a is shown in (a) of the figure, the circuit connection structure in the first transmission mode of the communication band a is shown in (b) of the figure, and the circuit connection structure in the second transmission mode of the communication band a is shown in (c) of the figure.

Further, the reception mode refers to the following mode: the high-frequency reception signal received by the antenna element 2 propagates through the switch circuit 30, the transmission/reception filter 11, the switch circuit 20, the reception low-noise amplifier 42, and the RFIC 3 in this order. In addition, the transmission mode refers to the following mode: the high-frequency transmission signal output from the RFIC 3 propagates through the transmission power amplifier 41, the switch circuit 20, the transmission/reception filter 11, the switch circuit 30, and the antenna element 2 in this order. The first transmission mode among the transmission modes is a transmission mode that gives priority to power efficiency in the transmission power amplifier 41, and the second transmission mode is defined as a transmission mode that gives priority to the magnitude of power in the transmission power amplifier 41.

As shown in fig. 2 (a), in the reception mode, in the switch circuit 20, (3) the common terminal 21a and the reception terminal 22b are connected, the common terminal 21a and the selection terminal 22C are connected, and the capacitance value of the DTC23 is set to C1 (second impedance value). In the first transmission mode, the switch circuit 20 is connected to (1) the common terminal 21a and the transmission terminal 22 a. In the second transmission mode, (2) the common terminal 21a and the transmission terminal 22a are connected, the common terminal 21a and the selection terminal 22C are connected, and the capacitance value of the DTC23 is set to C2 (first impedance value) in the switch circuit 20.

In describing the operation and effect of the connection structure of the high-frequency module 1 shown in fig. 2, the circuit structure of the high-frequency module according to the comparative example will be described.

Fig. 3 is a smith chart showing a circuit configuration of the high-frequency module according to the comparative example and impedances at respective ports. The upper layer of the figure shows the circuit configuration of the high-frequency module according to the comparative example.

The high-frequency module according to the comparative example includes a switch circuit 90, a transmission/reception filter 11, a transmission power amplifier 41, a reception low-noise amplifier 42, and impedance matching circuits 51 and 52. The high-frequency module according to the comparative example differs from the high-frequency module 1 according to the embodiment in the following circuit configuration: no additional DTC 23; and impedance matching circuits 51 and 52 are added.

The switch circuit 90 has a common terminal 91a, a transmission terminal 92a, and a reception terminal 92 b.

Fig. 3 (a) shows the impedance of the transmission power amplifier 41 in the frequency band a as viewed from the transmission terminal 92a (port T) of the switch circuit 90. Also taking into account the role of the impedance matching circuit 52, the impedance of the transmission power amplifier 41 in the frequency band a as viewed from the port T is, for example, located in an inductive and low impedance region. The impedance of the transmission-reception filter 11 in the frequency band a as viewed from the common terminal 91a (port C) of the switch circuit 90 is shown in (C) of fig. 3. Also taking into account the role of the impedance matching circuit 51, the impedance of the transmission-reception filter 11 in the frequency band a as viewed from the port C is located in an inductive and low-impedance region, for example. Fig. 3 (b) shows the impedance of the reception low noise amplifier 42 in the frequency band a as viewed from the reception terminal 92b (port R) of the switch circuit 90. The impedance of the reception low noise amplifier 42 in the frequency band a as viewed from the port R is, for example, substantially the reference impedance (e.g., 50 Ω).

In the case of the high-frequency module according to the comparative example, in the so-called transmission mode, as shown in (a) and (C) of fig. 3, the impedance of the transmission power amplifier 41 in the band a as viewed from the port T and the impedance of the transmission/reception filter 11 in the band a as viewed from the port C match. However, in the so-called reception mode, as shown in (b) and (C) of fig. 3, the impedance of the reception low noise amplifier 42 in the band a as viewed from the port R does not match the impedance of the transmission-reception filter 11 in the band a as viewed from the port C.

That is, in the high-frequency module according to the comparative example, impedance adjustment between the transmission mode and the reception mode cannot be achieved at the same time.

Fig. 4 is a smith chart showing the impedance of the high-frequency module 1 according to the embodiment in the first transmission (efficiency) mode. Fig. 4 (a) shows the impedance of the transmission power amplifier 41 in the frequency band a as viewed from the transmission terminal 22a (port T) of the switch circuit 20 in the first transmission mode. The impedance of the transmission power amplifier 41 in the frequency band a as viewed from the port T is, for example, in an inductive and low impedance region. The impedance of the transmission-reception filter 11 in the frequency band a as viewed from the common terminal 21a (port C) of the switch circuit 20 in the first transmission mode is shown in (b) of fig. 4. The impedance of the transmission-reception filter 11 in the frequency band a as viewed from the port C is, for example, in an inductive and low-impedance region.

In the high-frequency module 1 according to the present embodiment, in the first transmission mode, as shown in fig. 4 (a) and (b), the impedance of the transmission power amplifier 41 in the band a as viewed from the port T and the impedance of the transmission/reception filter 11 in the band a as viewed from the port C are matched. Further, in the first transmission mode, the selection terminal 22c is not connected to the common terminal 21a, but the selection terminal 22c may be connected to the common terminal 21a in the first transmission mode. In this case, the DTC23 in the first transmission mode may have a capacitance value (independently set) different from the capacitance value C1 of the DTC23 in the reception mode and the capacitance value C2 of the DTC23 in the second transmission mode. Further, the impedance matching circuit may be disposed between the transmission power amplifier 41 and the transmission terminal 22a so as to match the impedance of the transmission power amplifier 41 in the band a as viewed from the port T in the first transmission mode with the impedance of the transmission/reception filter 11 in the band a as viewed from the port C. Further, the impedance matching circuit may be disposed between the transmission/reception filter 11 and the common terminal 21 a.

Fig. 5 is a smith chart showing the impedance of the high-frequency module 1 according to the embodiment in the reception mode. Fig. 5 (a) shows the impedance of the reception low noise amplifier 42 in the frequency band a as viewed from the reception terminal 22b (port R) of the switch circuit 20 in the reception mode. The impedance of the reception low noise amplifier 42 in the frequency band a as viewed from the port R is, for example, substantially the reference impedance. Fig. 5 (b) shows the impedance of the transmission-reception filter 11 in the frequency band a as viewed from the common terminal 21a (port C) of the switch circuit 20 in the reception mode. The impedance of the transmission-reception filter 11 in the frequency band a as viewed from the port C is, for example, substantially the reference impedance.

In the case of the high-frequency module 1 according to the present embodiment, in the reception mode, as shown in fig. 5 (a) and (b), the impedance of the reception low-noise amplifier 42 in the band a as viewed from the port R matches the impedance of the transmission/reception filter 11 in the band a as viewed from the port C. The impedance matching in this receive mode is due to: the common terminal 21a and the selection terminal 22C are connected, and the capacitance value of the DTC23 is set to C1. As shown in fig. 5 (b), in a state where the DTC23 is not connected to the common terminal 21a, the impedance of the transmission/reception filter 11 in the band a as viewed from the port C is, for example, in an inductive and low impedance region, as in the first transmission mode. On the other hand, in a state where the DTC23 is connected to the common terminal 21a, since a capacitor is connected in parallel to the common terminal 21a, the phase of the impedance of the transmission/reception filter 11 as viewed from the port C is shifted clockwise on the iso-conductance circle on the admittance chart. Therefore, the impedance of the transmission/reception filter 11 in the frequency band a as viewed from the port C can be made to be substantially at the reference impedance by optimizing the capacitance value of the DTC23 to C1.

That is, in the high-frequency module 1 according to the present embodiment, by connecting the DTC23 set to the capacitance value C1 in parallel to the common terminal 21a in the reception mode, the impedance of the transmission power amplifier 41 in the band a as viewed from the port T and the impedance of the transmission/reception filter 11 in the band a as viewed from the port C can be matched as shown in (a) and (b) of fig. 5.

Fig. 6 is a smith chart showing the optimum impedance in the first transmission mode and the second transmission mode of the high-frequency module 1 according to the embodiment. The optimum point E (impedance that gives priority to power efficiency in band a) based on the efficiency circle (equivalent ratio circle) of the transmission power amplifier 41 in band a as viewed from the output terminal of the transmission power amplifier 41 in the first transmission (efficiency) mode is shown in the lower layer of fig. 6. In the lower layer of fig. 6, the optimum point G (impedance giving priority to output power in band a) based on the gain circle (equal gain circle) of the transmission power amplifier 41 in band a as viewed from the output terminal of the transmission power amplifier 41 in the second transmission mode is shown.

In the case of the high-frequency module 1 according to the present embodiment, in the first transmission mode in which the power efficiency is prioritized, as shown in fig. 4 (a) and (b), the impedance of the transmission power amplifier 41 in the band a as viewed from the port T is matched with the impedance of the transmission/reception filter 11 in the band a as viewed from the port C. In contrast, the optimum impedance G of the transmission power amplifier 41 in the second transmission mode in which the magnitude of the output power is prioritized is shifted to the low impedance side compared to the optimum impedance E of the transmission power amplifier 41 in the first transmission mode in which the power efficiency is prioritized. Therefore, similarly to making the optimum point E of the efficiency circle coincide with the optimum point G of the gain circle, the impedance of the transmission/reception filter 11 in the band a as viewed from the port C (or the port T1) in the second transmission mode is shifted to the low impedance side with respect to the impedance of the transmission/reception filter 11 in the band a as viewed from the port C (or the port T1) in the first transmission mode, whereby the impedance matching between the transmission power amplifier 41 and the transmission/reception filter 11 in the second transmission mode can be achieved. Here, in the second transmission mode, since the DTC23 is connected to the common terminal 21a and the capacitor is connected in parallel to the common terminal 21a, the phase of the impedance of the transmission/reception filter 11 as viewed from the port C (or the port T1) is shifted clockwise on the iso-conductance circle on the admittance chart. Therefore, the impedance of the transmission-reception filter 11 in the band a as viewed from the port C can be shifted to the low impedance side with respect to the impedance in the first transmission mode by optimizing the capacitance value of the DTC23 to C2.

That is, in the high-frequency module 1 according to the present embodiment, by connecting the DTC23 set to the capacitance value C2 in parallel to the common terminal 21a in the second transmission mode, the impedance of the transmission power amplifier 41 in the band a as viewed from the port C (or the port T1) can be matched to the impedance of the transmission/reception filter 11 in the band a as viewed from the port C (or the port T1).

That is, in the switch circuit 20 included in the high-frequency module 1 according to the present embodiment, (1) when only the transmission terminal 22a of the transmission terminal 22a, the reception terminal 22b, and the selection terminal 22c is connected to the common terminal 21a, the impedance of the transmission/reception filter 11 when viewed from the common terminal 21a toward the transmission/reception filter 11 is matched to the optimum impedance of the transmission power amplifier 41 in the first transmission mode having priority on power efficiency. In addition, (2) when the transmission terminal 22a and the selection terminal 22C of the transmission terminal 22a, the reception terminal 22b, and the selection terminal 22C are connected to the common terminal 21a, the DTC23 is set to a first capacitance value C2 (first impedance value), and the impedance of the transmission/reception filter 11 when viewed from the common terminal 21a toward the transmission/reception filter 11 is matched to the impedance of the transmission power amplifier 41 in the second transmission mode that gives priority to the magnitude of the output power. In addition, (3) when the reception terminal 22b and the selection terminal 22C of the transmission terminal 22a, the reception terminal 22b, and the selection terminal 22C are connected to the common terminal 21a, the DTC23 is set to a capacitance value C1 (second impedance value), and the impedance of the transmission/reception filter 11 when viewed from the common terminal 21a toward the transmission/reception filter 11 matches the impedance of the reception low-noise amplifier 42 when viewed from the common terminal 21a toward the reception low-noise amplifier 42.

Thus, in the high-frequency module 1 in which the transmission/reception path to which the transmission/reception filter 11 of the Time Division Duplex (TDD) system is applied is shared, it is possible to achieve both the impedance adjustment between the transmission mode of the transmission power amplifier 41 and the reception mode of the reception low noise amplifier 42 and the impedance adjustment between the first transmission mode and the second transmission mode of the transmission power amplifier 41.

[ high-frequency Module according to modification 3 ]

The high-frequency module 1A according to the present modification has the following configuration: in addition to the high-frequency module 1 according to embodiment 1, impedance matching in CA (carrier aggregation) is added.

Fig. 7 is a circuit diagram showing a connection state of the switch circuit according to the combination of CA in the high-frequency module 1A according to the modification of the embodiment.

The high-frequency module 1A according to the present modification differs from the high-frequency module 1 according to the embodiment in the following points: a reception filter 15 having a reception band of the communication band D as a passband, a reception low noise amplifier 43, a common terminal 21e, and a reception terminal 22e are added. Next, the high-frequency module 1A according to the present modification will be described centering on differences from the high-frequency module 1 according to the embodiment, with the description of the same aspects as those of the high-frequency module 1 according to the embodiment omitted. In fig. 7, only the essential components of the high-frequency module 1A according to the present modification are shown, but the high-frequency module 1A according to the present modification may include the antenna connection terminal 100, the switch circuit 30, the transmission/reception filter 12, the transmission filter 13, and the reception filter 14 included in the high-frequency module 1 according to the embodiment.

The reception filter 15 is a second filter having a reception band of the communication band D (second communication band) as a passband.

The reception low noise amplifier 43 has an input terminal and an output terminal, and the output terminal is connected to the RFIC 3, and the reception low noise amplifier 43 amplifies a high frequency reception signal of the communication band D.

The switch circuit 25 includes a common terminal 21e and a reception terminal 22e in addition to the terminals included in the switch circuit 20 according to the embodiment. The common terminal 21e (second common terminal) is connected to the reception filter 15. The reception terminal 22e (second selection terminal) is connected to the input terminal of the reception low noise amplifier 43.

The DTC23 is connected to a path connecting the selection terminal 22c to ground. The DTC23 is a capacitor whose capacitance value can be changed stepwise in accordance with switching of the connection of the switching circuit 25.

The switch circuit 25 can perform either (1) a first connection, which is a connection of the reception terminal 22b and the common terminal 21a, or (2) a second connection, which is a connection of the reception terminal 22e and the common terminal 21e, or the simultaneous connection of the 2 connections. That is, the high frequency module 1A can perform non-CA (nonca) of the communication band a and CA of the communication bands a and D by switching the connection by the switch circuit 25.

Here, as shown in fig. 7 (a), when the non-CA communication band a is executed, the DTC23 set to the capacitance value C1 is connected to the common terminal 21a by executing the above (1) and connecting the selection terminal 22C to the common terminal 21 a. As shown in fig. 7 (b), when the communication band a and the communication band D CA are executed, the DTC23 set to the capacitance value C3 is connected to the common terminal 21a by simultaneously executing the above (1) and (3) and connecting the selection terminal 22C to the common terminal 21 a. In the CA of the communication band a and the communication band D, the DTC23 may be connected to the common terminal 21e instead of the common terminal 21 a.

That is, the capacitance value C1 of DTC23 at the first connection is different from the capacitance value C3 of DTC23 at the first connection and the second connection.

Thereby, the capacitance value of the DTC23 can be changed between non-CA and CA, and therefore, even when CA is performed, the combined impedance of the filter of the CA target viewed from the common terminal can be matched with the impedance of the reception low noise amplifier viewed from the common terminal. Therefore, in the high-frequency module 1A in which the transmission/reception path to which the transmission/reception filter 11 applied to the Time Division Duplex (TDD) system is disposed is shared, impedance adjustment between the transmission mode and the reception mode and impedance adjustment between different transmission modes (the first transmission mode and the second transmission mode) can be achieved at the same time, and impedance matching at the time of CA can be achieved by varying the capacitance of the DTC23 for performing the impedance adjustment.

The reception filter 15 may be a transmission/reception filter applied to the TDD scheme.

In addition, although the configuration of executing the CA of the reception system is illustrated in the present modification, the high-frequency module according to the present invention includes a configuration of executing the CA of the transmission system or a configuration of executing both the CA of the transmission system and the CA of the reception system. For example, as a configuration for executing CA of the transmission system, it is sufficient to arrange a transmission filter instead of the reception filter 15 in the high-frequency module 1A according to the present modification and arrange a transmission power amplifier instead of the reception low-noise amplifier 43.

(other embodiments)

The high-frequency module and the communication device according to the present invention have been described above by referring to the embodiments and the modifications, but the present invention is not limited to the embodiments and the modifications. Other embodiments in which arbitrary components in the above-described embodiment and modifications are combined, modifications in which various modifications that can be made to the above-described embodiments by those skilled in the art are made without departing from the spirit and scope of the present invention, and various devices incorporating the high-frequency module and the communication device according to the present invention are also included in the present invention.

For example, in the high-frequency module and the communication device according to the embodiments and the modifications, matching elements such as inductors and capacitors, and switching circuits may be connected between the respective components. The inductor may include a wiring inductance formed by a wiring connecting the components.

Industrial applicability

The present invention is widely applicable to communication devices such as mobile phones as a high-frequency module and a communication device having a transmission/reception filter to which the TDD scheme is applied.

Description of the reference numerals

1. 1A: a high frequency module; 2: an antenna element; 3: RF signal processing circuitry (RFIC); 4: a communication device; 11. 12: a transmitting/receiving filter; 13: a transmission filter; 14. 15: a receiving filter; 20. 25, 30, 90: a switching circuit; 21a, 21b, 21c, 21d, 21e, 31a, 91 a: a common terminal; 22a, 92 a: a transmission terminal; 22b, 22e, 92 b: a receiving terminal; 22c, 32a, 32b, 32 c: a selection terminal; 23: a DTC; 41: a transmission power amplifier; 42. 43: receiving a low noise amplifier; 51. 52: an impedance matching circuit; 100: an antenna connection terminal.