JP2022101869A - Amplifier circuit - Google Patents

Abstract

To suppress deterioration of electrical characteristics.SOLUTION: An amplifier circuit 1 includes a first terminal 11 and a second terminal 12, an amplifier 30 provided on a first path 21 connecting the first terminal 11 and the second terminal 12, a switch 61 connected between the ground and a node 51 on a second path 22 that is branched from the first path 21, bypasses the amplifier 30, and is joined to the first path 21, a switch 62 connected between a node 52 which is closer to the second terminal 12 than the node 51 on the second path 22, and the ground, and a switch 71 or 72 arranged in series on the second path 22.SELECTED DRAWING: Figure 1

Description

The present invention relates to an amplifier circuit.

Communication devices such as mobile terminals are provided with an amplifier circuit that amplifies high-frequency signals. As an example of an amplifier circuit, Patent Document 1 discloses an amplifier circuit including an amplifier that amplifies a high-frequency signal, a bypass path that bypasses the amplifier, and a switch circuit provided in the bypass path. The switch circuit includes a series-connected switch arranged in series on the bypass path and a parallel-connected switch connecting the bypass path and ground.

International Publication No. 2019/098145

When the amplifier is operating, the series connection switch on the bypass path becomes non-conducting. At this time, a portion of the bypass path whose one end is opened by the series connection switch may deteriorate the electrical characteristics of the amplifier.

Therefore, an object of the present invention is to provide an amplifier circuit in which deterioration of electrical characteristics is suppressed.

The amplifier circuit according to one aspect of the present invention has an amplifier provided on a first path connecting the first terminal and the second terminal, the first terminal and the second terminal, and an amplifier branched from the first path. The first switch connected between the first node on the second path and the ground that bypasses and joins the first path, and the second node and the ground that are closer to the second terminal than the first node on the second path. A second switch connected between the two and a second switch arranged in series between the first terminal and the first node or between the second terminal and the second node on the second path. It is equipped with 3 switches.

According to the amplifier circuit according to the present invention, deterioration of electrical characteristics can be suppressed.

FIG. 1 is a circuit diagram of an amplifier circuit according to an embodiment. FIG. 2A is a circuit diagram of the amplifier circuit according to the embodiment in the amplification mode. FIG. 2B is a circuit diagram of the amplifier circuit according to the embodiment in the bypass mode. FIG. 3 is a circuit diagram of an amplifier circuit according to Comparative Example 1. FIG. 4 is a circuit diagram of an amplifier circuit according to Comparative Example 2.

Hereinafter, the amplifier circuit according to the embodiment of the present invention will be described in detail with reference to the drawings. In addition, all of the embodiments described below show a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Therefore, among the components in the following embodiments, the components not described in the independent claims are described as arbitrary components.

Further, each figure is a schematic view and is not necessarily exactly illustrated. Therefore, for example, the scales and the like do not always match in each figure. Further, in each figure, substantially the same configuration is designated by the same reference numeral, and duplicate description will be omitted or simplified.

Further, as used herein, the term "connected" includes not only the case of being directly connected by a connection terminal and / or a wiring conductor, but also the case of being electrically connected via another circuit element. Further, "connected between A and B" means that both A and B are connected between A and B.

Further, in the present specification, ordinal numbers such as "first" and "second" do not mean the number or order of constituent elements unless otherwise specified, and avoid confusion of the same kind of constituent elements and distinguish them. It is used for the purpose of

(Embodiment)
[1. Amplifier circuit configuration]
First, the amplifier circuit according to the embodiment will be described with reference to FIG.

FIG. 1 is a circuit diagram of an amplifier circuit 1 according to the present embodiment. The amplifier circuit 1 shown in FIG. 1 is provided in, for example, a receiving circuit that processes a high-frequency receiving signal (hereinafter, simply referred to as a high-frequency signal) received by an antenna. The high frequency signal is a signal compliant with a communication standard such as Wi-Fi (registered trademark), LTE (Long Term Evolution) or 5G (5th Generation). For example, the high frequency signal is a signal in the 1 GHz band, 2.4 GHz band, or 5 GHz band, but is not limited thereto.

As shown in FIG. 1, the amplifier circuit 1 includes a first terminal 11 and a second terminal 12, an amplifier 30, and a plurality of switches 61 to 63, 71, 72 and 80. Further, the amplifier circuit 1 includes a first path 21 and a second path 22.

The first terminal 11 is an input terminal of the amplifier circuit 1. A high frequency signal is input to the first terminal 11.

The second terminal 12 is an output terminal of the amplifier circuit 1. The high frequency signal input to the first terminal 11 is output from the second terminal 12.

The first path 21 is a path connecting the first terminal 11 and the second terminal 12.

The second path 22 is a path that branches from the first path 21, bypasses the amplifier 30, and joins the first path 21. One end of the second path 22 is a branch point 41, and the other end of the second path 22 is a confluence point 42. That is, the second path 22 is a path connecting the branch point 41 and the confluence point 42 that does not pass through the amplifier 30. The branch point 41 may coincide with the first terminal 11. Further, the confluence point 42 may coincide with the second terminal 12.

The amplifier 30 is provided on the first path 21. The amplifier 30 is, for example, a low noise amplifier. The configuration of the amplifier 30 is not particularly limited. For example, the amplifier 30 may have a single-stage configuration or a multi-stage configuration.

The switch 61 is an example of a first switch connected between the node 51 on the second path 22 and the ground. The switch 62 is an example of a second switch connected between the node 52 on the second path 22 and the ground. The switch 63 is an example of a fifth switch connected between the node 53 on the second path 22 and the ground.

The node 52 is a node closer to the second terminal 12 (and the confluence point 42) than the node 51. The node 53 is a node closer to the second terminal 12 (and the confluence 42) than the node 52. That is, the nodes 51 to 53 and the switches 61 to 63 connected to them are arranged in this order between the branch point 41 and the confluence point 42.

The switches 61 to 63 can switch between a conductive state (on) and a non-conducting state (off), respectively. When the switches 61 to 63 are turned on, the corresponding nodes 51 to 53 on the second path 22 are set to the ground potential (0V). The switches 61 to 63 are also referred to as shunt switches, respectively.

The switch 71 is an example of a third switch arranged in series on the second path 22. Specifically, the switch 71 is arranged between the first terminal 11 (and the branch point 41) and the node 51. That is, the switch 71 is provided at a position closer to the branch point 41 than the switch 61 closest to the branch point 41 among the plurality of switches 61 to 63.

The switch 72 is an example of a fourth switch arranged in series on the second path 22. Specifically, the switch 72 is arranged between the second terminal 12 (and the confluence 42) and the node 52. More specifically, the switch 72 is arranged between the confluence 42 and the node 53. That is, the switch 72 is provided at a position closer to the confluence 42 than the switch 63 closest to the confluence 42 among the plurality of switches 61 to 63.

The switches 71 and 72 can switch between a conductive state (on) and a non-conducting state (off), respectively. When the switches 71 and 72 are turned on, the second path 22 is in a conductive state, that is, the branch point 41 and the confluence point 42 are electrically connected via the second path 22. The switches 71 and 72 are also referred to as series switches, respectively.

In this embodiment, the second path 22 is divided into six parts by switches 71 and 72 and nodes 51 to 53. As described above, by increasing the number of divisions of the second path 22, the wiring length of each portion can be shortened, and the parasitic impedance of each portion can be reduced. This makes it possible to improve the electrical characteristics of the amplifier 30. Details will be described later.

The switch 80 is an example of a sixth switch connected between the node 43 on the first path 21 and the ground. The node 43 is located between the branch point 41 and the amplifier 30.

The switch 80 can switch between a conductive state (on) and a non-conducting state (off). When the switch 80 is turned on, the node 43 is set to the ground potential (0V). That is, the input terminal of the amplifier 30 is set to the ground potential. The switch 80 is also referred to as a shunt switch.

Each of the first path 21 and the second path 22 is a signal line composed of wiring, vias, electrodes and / or terminals formed by using a conductive member such as metal. Further, the first terminals 11 and 12 are terminals or electrodes located at the end of the signal line.

The amplifier 30 is composed of, for example, a Si system, a field effect transistor (FET) formed by using GaAs as a material, or a bipolar transistor including a heterobipolar transistor (HBT). The switches 61 to 63, 71, 72 and 80 are each realized by a switching element such as a FET or a bipolar transistor.

[2. Operation of amplifier circuit]
Subsequently, the operation of the amplifier circuit 1 will be described. The amplifier circuit 1 has two operation modes, an amplifier mode and a bypass mode.

The amplification mode is a mode in which the amplifier 30 operates. The operating time of the amplifier 30 means a period during which the amplifier circuit 1 operates in the amplifier mode. Specifically, the amplifier 30 amplifies the high frequency signal input to the first terminal 11 and outputs it from the second terminal 12. In this amplification mode, the high frequency signal is propagated through the first path 21.

FIG. 2A is a circuit diagram of the amplifier circuit 1 according to the present embodiment in the amplification mode. In FIG. 2A, the flow of high frequency signals is represented by white arrows. The same applies to FIG. 2B, which will be described later.

As shown in FIG. 2A, in amplification mode, switches 71, 72 and 80 are in a non-conducting state. When the switches 71 and 72 are in a non-conducting state, the second path 22 is cut off. When the switch 80 is in the non-conducting state, the high frequency signal input to the first terminal 11 can be input to the amplifier 30.

Further, in the amplification mode, all the switches 61 to 63 are in a conductive state. As a result, all the nodes 51 to 53 are set to the ground potential. That is, three different points on the second path 22 are set to the ground potential.

The bypass mode is a mode in which the amplifier 30 is not operated. The non-operating state of the amplifier 30 means a period during which the amplifier circuit 1 operates in the bypass mode. In the bypass mode, the function of the amplifier 30 is turned off. The high frequency signal input to the first terminal 11 is propagated through the second path 22 and output from the second terminal 12.

FIG. 2B is a circuit diagram of the amplifier circuit 1 according to the present embodiment in the bypass mode. As shown in FIG. 2B, in bypass mode, switches 71, 72 and 80 are in a conductive state. When the switches 71 and 72 are in a conductive state, the branch point 41 and the confluence point 42 are connected to each other via the second path 22 at substantially the same potential. Further, when the switch 80 becomes conductive, it is possible to suppress the input of the high frequency signal to the amplifier 30.

Further, in the bypass mode, all the switches 61 to 63 are in a non-conducting state. As a result, it is possible to prevent the high frequency signal from being propagated through the second path 22 from the branch point 41 to the confluence point 42.

In the present embodiment, the amplifier circuit 1 or the communication device including the amplifier circuit 1 includes a control circuit (not shown) that controls the operation of the amplifier circuit 1. For example, the control circuit switches between amplification mode and bypass mode based on the magnitude of the signal power of the input high frequency signal. The control circuit operates the amplifier circuit 1 in the bypass mode when the signal power of the high frequency signal is larger than the threshold value, and operates the amplifier circuit 1 in the amplification mode when the signal power of the high frequency signal is smaller than the threshold value. The control circuit controls the on / off of the amplifier 30 and the on / off of each of the switches 61 to 63, 71, 72 and 80. The conditions for switching the operation mode of the amplifier circuit 1 are merely examples, and are not particularly limited.

[3. Effect of wiring route]
Subsequently, the influence of the first path 21 and the second path 22 of the amplifier circuit 1 on the electrical characteristics of the amplifier 30 will be described.

The first path 21 is provided at a predetermined distance so that the input side portion and the output side portion of the amplifier 30 do not come too close to each other. This makes it possible to increase the isolation between the input and output of the amplifier 30. If the high frequency signal amplified by the amplifier 30 wraps around to the input of the amplifier 30 due to electromagnetic field coupling, the amplifier 30 may oscillate. By increasing the isolation between the input and output of the amplifier 30, the oscillation of the amplifier 30 can be suppressed.

In this case, the branch point 41 located on the input side of the first path 21 and the confluence point 42 located on the output side are provided at a predetermined distance from each other. Therefore, the second path 22 is composed of wiring having a wiring length of a certain value or more. When the wiring length of the second path 22 becomes long, the parasitic impedance component of the wiring of the second path 22 may affect the electrical characteristics of the amplifier 30 depending on the position of the switch. Hereinafter, this effect will be specifically described with reference to FIGS. 3 and 4.

FIG. 3 is a circuit diagram of the amplifier circuit 1x according to Comparative Example 1. In the amplifier circuit 1x according to Comparative Example 1, a T-shaped switch circuit is arranged on the second path 22. Specifically, switches 71 and 72 are arranged in series on the second path 22, and the switch 61 is connected to the node 51 and the ground. That is, the amplifier circuit 1x has a configuration in which the two switches 62 and 63 are removed from the amplifier circuit 1 shown in FIG.

In the amplifier circuit 1x, the switches 61, 71 and 72 are connected to the node 51, and the wiring length between the node 51 and each of the switches 61, 71 and 72 is sufficiently short. On the other hand, a wiring 23 having a predetermined wiring length exists between the branch point 41 and the switch 71, and a wiring 24 having a predetermined wiring length exists between the switch 72 and the confluence point 42.

When the amplifier circuit 1x operates in the amplification mode, the switch 71 is in the non-conducting state, and the switch 61 is in the conducting state. In this case, the wiring 23 functions as an open stub. Specifically, since the input impedance of the amplifier 30 when viewed from the first terminal 11 changes depending on the wiring 23, impedance matching cannot be achieved and the loss becomes large.

As described above, when the wiring length of the wiring 23 connecting the branch point 41 and the switch 71 is long, the amplification characteristic of the amplifier 30 deteriorates. Although the wiring 23 on the branch point 41 side has been described in FIG. 3, the same applies to the wiring 24 on the confluence point 42 side. The wiring 24 changes the output impedance of the amplifier 30, impedance matching cannot be achieved, and the loss becomes large.

FIG. 4 is a circuit diagram of the amplifier circuit 1y according to Comparative Example 2. In the amplifier circuit 1y according to Comparative Example 2, the wiring length between the branch point 41 and the switch 71 is sufficiently shorter than that of the amplifier circuit 1x according to Comparative Example 1, whereas the switch 71 and the node 51 There is a wiring 23 having a long wiring length between the two.

When the amplifier circuit 1y operates in the amplification mode, the switch 71 is in the non-conducting state, and the switch 61 is in the conducting state. In this case, the wiring 23 functions as a short stub or a monopole antenna. When the wiring 23 functions as a short stub, LC resonance occurs between the inductor component of the wiring 23 and the capacitor component of the switch 71. Since the input impedance of the amplifier 30 changes due to the formation of the resonance circuit, impedance matching cannot be achieved and the loss becomes large.

Further, when the wiring 23 functions as a monopole antenna, the wiring 23 receives a signal from the outside, and the received signal becomes noise and deteriorates the amplification characteristic of the amplifier 30. In addition, electromagnetic field coupling with the output side and the input side of the amplifier 30 may occur via the wiring 23, and the isolation of the input and output of the amplifier 30 deteriorates.

In this way, even if the wiring connecting the branch point 41 and the switch 71 is shortened, the wiring length of the wiring 23 between the switch 71 and the node 51 becomes long, so that the amplification characteristic of the amplifier 30 deteriorates. Although the wiring 23 on the branch point 41 side has been described in FIG. 4, the same applies to the wiring 24 on the confluence point 42 side. The wiring 24 changes the output impedance of the amplifier 30, impedance matching cannot be achieved, and the loss becomes large.

On the other hand, in the amplifier circuit 1 according to the present embodiment, the second path 22 is divided into a plurality of portions by a plurality of nodes. Specifically, as shown in FIG. 1, the second path 22 is divided into six parts by two switches 71 and 72 and three nodes 51 to 53. In this embodiment, the nodes 51 to 53 and the switches 71 and 72 are arranged so that most of the second path 22 is composed of the wirings 23 and 24 located between the node 51 and the node 53. ..

Specifically, the switch 71 is arranged so that the wiring length between each of the branch point 41 and the node 51 is sufficiently short. For example, the wiring length between the switch 71 and the branch point 41 and the wiring length between the switch 71 and the node 51 are both shorter than the wiring lengths of the wirings 23 and 24, respectively. For example, one end of the switch 71 may be directly connected to the branch point 41, and the wiring length may be considered to be substantially zero. Similarly, the other end of the switch 71 is directly connected to the node 51, and the wiring length may be considered to be substantially zero.

The switch 72 is arranged so that the wiring length between each of the node 53 and the confluence 42 is sufficiently short. For example, the wiring length between the switch 72 and the confluence 42 and the wiring length between the switch 72 and the node 53 are both shorter than the wiring lengths of the wirings 23 and 24, respectively. For example, one end of the switch 72 may be directly connected to the confluence 42, and the wiring length may be considered to be substantially zero. Similarly, the other end of the switch 72 is directly connected to the node 53, and the wiring length may be considered to be substantially zero.

In this way, the switch 71 and the node 51 (switch 61) are arranged near the branch point 41, and the switch 72 and the node 53 (switch 63) are arranged near the confluence point 42. By shortening the wiring length between the branch point 41 and the switch 71, it is possible to prevent the wiring portion from behaving as an open stub as shown in FIG. Therefore, the change in the input impedance of the amplifier 30 is suppressed, impedance matching is facilitated, and the loss of signal power is suppressed. Similarly, by shortening the wiring length between the switch 72 and the confluence 42, it is possible to prevent the wiring portion from behaving as an open stub. Therefore, the change in the output impedance of the amplifier 30 is suppressed, impedance matching is facilitated, and the loss of signal power is suppressed.

Further, by arranging the switches 71 and 72 near the branch point 41 or the confluence point 42, respectively, most of the second path 22 is composed of the wirings 23 and 24. The wiring 23 and the wiring 24 are separated by the node 52.

In the amplification mode, the nodes 51 to 53, which are the ends of the wirings 23 and 24, are set to the ground potential (0V), respectively. That is, both ends of the wiring 23 and both ends of the wiring 24 are set to the ground potential. As a result, it is possible to prevent the wirings 23 and 24 from behaving as the short stub or monopole antenna shown in FIG. Therefore, it is possible to suppress the loss of signal power and the generation of noise, and improve the isolation between the input and output of the amplifier 30.

The node 52 is located, for example, at the midpoint of the wiring path connecting the node 51 and the node 53. As a result, the wiring length of the wiring 23 and the wiring length of the wiring 24 can be made equal. In this embodiment, the wiring lengths of the wirings 23 and 24 are less than λ / 4.

λ is a wavelength corresponding to the maximum frequency of the operation guarantee of the amplifier 30. The maximum frequency for guaranteeing the operation of the amplifier 30 is a predetermined design value. For example, the maximum frequency for guaranteeing the operation of the amplifier 30 is a value described in a specification or the like. λ is represented by λ = c / f, where f is the maximum frequency and c is the speed of light.

In particular, when the wiring length of the wiring 23 or 24 is λ / 4 or more, the impedance component of the wiring 23 or 24 becomes large, and the electrical characteristics of the amplifier 30 are likely to be deteriorated. Specifically, the wiring 23 or 24 behaves as a short stub or a monopole antenna shown in FIG. 4, and tends to cause a loss of signal power and noise, and a decrease in isolation between the input and output of the amplifier 30. Become. On the other hand, in the present embodiment, since the wiring lengths of the wirings 23 and 24 are less than λ / 4, the loss of signal power and the generation of noise are suppressed, and the wiring between the input and output of the amplifier 30 is suppressed. Isolation can be improved.

When the wiring length of the second path 22 is long and the total of the wiring length of the wiring 23 and the wiring length of the wiring 24 is λ / 2 or more, the wiring length of at least one of the wirings 23 and 24 is less than λ / 4. Can no longer be. In this case, the amplifier circuit 1 may include a new switch (shunt switch) connected between the second path 22 and the ground. That is, the number of shunt switches included in the amplifier circuit 1 and the number of nodes to which the shunt switches are connected may be 4 or more. By arranging four or more nodes at equal intervals, the length of wiring between adjacent nodes can be made less than λ / 4. The intervals between the nodes do not have to be equal.

On the contrary, when the wiring length of the second path 22 is short, the amplifier circuit 1 may not include the switch 63. That is, the number of shunt switches included in the amplifier circuit 1 and the number of nodes to which the shunt switches are connected may be 2. The wiring length of the wiring 24 can be regarded as substantially 0 without providing the node 53 and the switch 63.

Similarly, the wiring length between the switch 61 and the node 51 and the wiring length between the switch 61 and the ground may be shorter than the wiring lengths of the wirings 23 and 24, respectively. As a result, it is possible to prevent an unnecessary impedance component from deteriorating the electrical characteristics of the amplifier 30. The wiring length between the switch 62 and each of the node 52 and the ground, and the wiring length between the switch 63 and each of the node 53 and the ground may be the same.

[4. Effect etc.]
As described above, the amplifier circuit 1 according to the present embodiment is the amplifier 30 provided on the first path 21 connecting the first terminal 11 and the second terminal 12 and the first terminal 11 and the second terminal 12. And the switch 61 connected between the node 51 on the second path 22 that branches from the first path 21 and joins the first path 21 by bypassing the amplifier 30, and the switch 61 on the second path 22. A switch 62 connected between the node 52 closer to the second terminal 12 than the node 51 and the ground, and a switch 71 arranged in series on the second path 22 are provided. Further, for example, the amplifier circuit 1 includes a switch 63 connected between the node 53 and the ground, which are closer to the second terminal 12 than the node 52 on the second path 22.

In this way, since the plurality of points (specifically, the nodes 51 and 52) of the second path 22 can be set to the ground potential, it is possible to suppress the occurrence of a portion having a long wiring length in the second path 22. Can be done. Therefore, it is possible to suppress a part of the second path 22 from functioning as an open stub, a short stub, or a monopole antenna. As a result, it is possible to suppress the generation of noise and the deterioration of isolation, so that the deterioration of the electrical characteristics of the amplifier circuit 1 can be suppressed.

Further, for example, the switch 71 is arranged between the first terminal 11 and the node 51. Further, for example, the amplifier circuit 1 includes a switch 72 arranged in series on the second path 22. The switch 72 is arranged between the second terminal 12 and the node 52.

As a result, the number of divisions of the second path 22 can be increased, so that it is possible to further suppress the occurrence of a portion having a long wiring length in the second path 22. Therefore, it is possible to more strongly suppress the generation of noise and the deterioration of isolation.

Further, for example, the wiring length of the wiring 23 between the node 51 and the node 52 is less than λ / 4 when the wavelength corresponding to the maximum frequency of the operation guarantee of the amplifier 30 is λ. Further, for example, the wiring length of the wiring 24 between the node 52 and the node 53 is less than λ / 4.

As a result, the wiring lengths of the wirings 23 and 24 can be shortened, so that the generation of noise and the deterioration of isolation can be suppressed more strongly.

Further, for example, the switches 61 and 62 are in a conductive state when the amplifier 30 is operating, and are in a non-conducting state when the amplifier 30 is not operating. Further, for example, the switch 63 is in a conductive state when the amplifier 30 is operating, and is in a non-conducting state when the amplifier 30 is not operating.

As a result, since a plurality of points of the second path 22 are set to the ground potential in the amplification mode, it is possible to suppress a part of the second path 22 from functioning as an open stub, a short stub, or a monopole antenna. This makes it possible to suppress the generation of noise and the deterioration of isolation.

Further, for example, the switch 71 goes into a non-conducting state when the amplifier 30 operates, and goes into a non-conducting state when the amplifier 30 does not operate. Further, for example, the switch 72 goes into a non-conducting state when the amplifier 30 operates, and goes into a non-conducting state when the amplifier 30 does not operate.

This makes it possible to switch between the amplification mode and the bypass mode.

Further, for example, the amplifier circuit 1 includes a switch 80 connected between the node 43 on the first path 21 and the ground. The node 43 is located between the branch point 41 between the first path 21 and the second path 22 and the amplifier 30. Further, for example, the switch 80 goes into a non-conducting state when the amplifier 30 operates, and goes into a non-conducting state when the amplifier 30 does not operate.

As a result, it is possible to suppress the input of the high frequency signal to the amplifier 30 in the bypass mode.

Further, for example, the amplifier 30 is a low noise amplifier that amplifies a high frequency received signal.

As a result, the noise of the high frequency reception signal can be sufficiently suppressed, so that the amplifier circuit 1 can be effectively used for the reception circuit and the like.

(others)
Although the amplifier circuit according to the present invention has been described above based on the above-described embodiment and the like, the present invention is not limited to the above-described embodiment.

For example, the amplifier circuit 1 does not have to include the switch 80. Further, the amplifier circuit 1 does not have to include one of the switches 71 and 72. Further, the amplifier circuit 1 does not have to include any one of the switches 61 to 63.

Further, for example, the amplifier circuit 1 may be provided in a transmission circuit that processes a high-frequency transmission signal transmitted from the antenna. The amplifier 30 may be a power amplifier that amplifies a high frequency transmission signal.

Further, for example, the present invention may be realized as a receiving circuit, a transmitting circuit or a transmitting / receiving circuit including an amplifier circuit 1, or a front-end module or a communication device including the receiving circuit, the transmitting circuit or the transmitting / receiving circuit. ..

In addition, it can be realized by arbitrarily combining the components and functions in each embodiment within the range obtained by applying various modifications to each embodiment and the purpose of the present invention. Forms are also included in the present invention.

The present invention can be used as an amplifier circuit in which deterioration of electrical characteristics is suppressed, and can be used, for example, in a communication terminal such as a mobile phone.

1 Amplifier circuit 11 1st terminal 12 2nd terminal 21 1st path 22 2nd path 23, 24 Wiring 30 Amplifier 41 Branch point 42 Confluence point 43, 51, 52, 53 Node 61, 62, 63, 71, 72, 80 switch

Claims (13)

1st terminal and 2nd terminal,
An amplifier provided on the first path connecting the first terminal and the second terminal,
A first switch connected between the first node on the second path, which branches from the first path, bypasses the amplifier, and joins the first path, and ground.
A second switch connected between the second node and the ground, which are closer to the second terminal than the first node on the second path,
A third switch arranged in series between the first terminal and the first node or between the second terminal and the second node on the second path is provided.
Amplifier circuit. The third switch is arranged between the first terminal and the first node.
The amplifier circuit according to claim 1. The wiring length of the second path between the first node and the second node is less than λ / 4 when the wavelength corresponding to the maximum frequency of the operation guarantee of the amplifier is λ.
The amplifier circuit according to claim 1 or 2. The first switch and the second switch are in a conductive state when the amplifier is operating, and are in a non-conducting state when the amplifier is not operating.
The amplifier circuit according to any one of claims 1 to 3. The third switch goes into a non-conducting state when the amplifier operates, and goes into a non-conducting state when the amplifier does not operate.
The amplifier circuit according to any one of claims 1 to 4. Further, a fourth switch arranged in series on the second path is provided.
The fourth switch is arranged between the second terminal and the second node.
The amplifier circuit according to any one of claims 1 to 4. The fourth switch goes into a non-conducting state when the amplifier operates, and goes into a non-conducting state when the amplifier does not operate.
The amplifier circuit according to claim 6. Further, a fifth switch connected between the third node and the ground, which are closer to the second terminal than the second node on the second path, is provided.
The amplifier circuit according to any one of claims 1 to 7. The wiring length of the second path between the second node and the third node is less than λ / 4 when the wavelength corresponding to the maximum frequency of the operation guarantee of the amplifier is λ.
The amplifier circuit according to claim 8. The fifth switch is in a conductive state when the amplifier is operating, and is in a non-conducting state when the amplifier is not operating.
The amplifier circuit according to claim 8 or 9. Further, a sixth switch connected between the fourth node on the first path and the ground is provided.
The fourth node is located between the branch point between the first path and the second path and the amplifier.
The amplifier circuit according to any one of claims 1 to 10. The sixth switch goes into a non-conducting state when the amplifier operates, and goes into a non-conducting state when the amplifier does not operate.
The amplifier circuit according to claim 11. The amplifier is a low noise amplifier that amplifies a high frequency received signal.
The amplifier circuit according to any one of claims 1 to 12.

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