Switching circuit

Abstract

Embodiments relate to a switching circuit. A switching circuit according to an embodiment includes a first terminal connected to a first node, a first switch having a first end connected to the first node and a second end connected to a second node, a second switch and a first resistor connected in parallel between second and third nodes, and a second terminal connected to the third node. A third switch having a first end connected to the second node; a first inductor having a first end connected to the second end of the third switch and a grounded second end; a fourth switch having a first end connected to the first node and a second end connected to the fourth node; a fifth switch and a second resistor connected in parallel between the fourth and fifth nodes, a third terminal connected to the fifth node, a sixth switch having a first end connected to the fourth node, and a second inductor having a first end connected to a second end of the sixth switch and a grounded second end.

Description

[0001] Related Applications

[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2023-146961 (filing date: September 11, 2023), and the present application incorporates all the contents of the basic application by reference. Technical Field

[0003] Embodiments relate to switching circuits. Background Art

[0004] As a switch for transmitting high-frequency signals, a SPDT (Single Pole Double Throw) switch is known. The SPDT switch selects only one of two individual terminals and connects it to a common terminal to transmit a high-frequency signal. Summary of the invention

[0005] The switching circuit of the embodiment includes a first terminal connected to a first node, a first switch having a first end connected to the first node and a second end connected to a second node, a second switch connected in parallel between the second node and a third node and a first resistor, a second terminal connected to the third node, a third switch having a first end connected to the second node, a first inductor having a first end connected to the second end of the third switch and a second end connected to ground, a fourth switch having a first end connected to the first node and a second end connected to a fourth node, a fifth switch connected in parallel between the fourth node and a fifth node and a second resistor, a third terminal connected to the fifth node, a sixth switch having a first end connected to the fourth node, and a second inductor having a first end connected to the second end of the sixth switch and a second end connected to ground.

[0006] According to this embodiment, a switch circuit capable of improving the loss of high-frequency signals can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a block diagram showing an example of the configuration of a communication system including the switching circuit according to the first embodiment.

[0008] Figure 2 This is a circuit diagram showing an example of the configuration of the switch circuit according to the first embodiment.

[0009] Figure 3 : is a circuit diagram showing an example of a connection state of the switch circuit according to the first embodiment.

[0010] Figure 4 This is a circuit diagram showing an example of an equivalent circuit of the switch circuit and the individual functional circuits according to the first embodiment.

[0011] Figure 5 This is a graph showing an example of insertion loss in the switch circuit according to the first embodiment.

[0012] Figure 6 This is a graph showing an example of the maximum available gain in the switching circuit of the first embodiment.

[0013] Figure 7 This is a graph showing an example of the reflection loss in the switch circuit according to the first embodiment.

[0014] Figure 8 This is a circuit diagram showing an example of the configuration of a switch circuit according to the first modification.

[0015] Fig. 9 : is a circuit diagram showing an example of the configuration of a switch circuit according to the second embodiment.

[0016] Fig.10 This is a circuit diagram showing an example of the configuration of a switch circuit according to the third embodiment.

[0017] Description of Reference Numerals

[0018] 1. 1A, 1B, 1C…Switching circuit

[0019] 2…Common function circuit

[0020] 3-1, 3-2, ..., 3-n... Individual functional circuits

[0021] 10-1, 10-2, ..., 10-n... units

[0022] 11-1, 11-2, ..., 11-n, 12-1, 12-2, ..., 12-n, 13-1, 13-2, ..., 13-n, 42, 43 ... switch

[0023] 15-1, 15-2, ..., 15-n, 45 ... resistors

[0024] 17-1, 17-2, ..., 17-n, 47, 51-1, 51-2, 51-3 ... inductance

[0025] 20…Common terminal

[0026] 30-1, 30-2, ..., 30-n... Individual terminals

[0027] 50-1, 50-2, 50-3…matching circuit

[0028] 52-1, 52-2, 52-3…Capacitors

[0029] 100…Control circuit

[0030] SYS…Communication system

[0031] Load…Load resistance DETAILED DESCRIPTION

[0032] In the following, the embodiments are described with reference to the accompanying drawings. In the following description, the same reference numerals are used for components having substantially the same function and configuration. When the components represented by reference numerals containing the same text do not need to be distinguished from each other, these components are referred to by reference numerals containing only text.

[0033] In the following description, a first element “connected to” another second element includes that the first element is indirectly connected to the second element via an intermediate element that is always or selectively conductive, or is directly connected to the second element without an intermediate element.

[0034] In the following description, a state in which both ends of a switch are electrically connected via the switch is referred to as an on-state, and a state in which both ends of a switch are not electrically connected via the switch is referred to as an off-state.

[0035] 1. First Implementation

[0036] 1.1 Overall composition

[0037] Figure 1 1 is a block diagram showing an example of the configuration of a communication system including the switch circuit of the first embodiment. The communication system SYS includes a switch circuit 1, a common function circuit 2, and individual function circuits 3-1 and 3-2. The communication system SYS is, for example, a transceiver system for wireless communication in a high frequency band of 600 MHz or more and 6 GHz or less.

[0038] The switch circuit 1 is formed, for example, on an SOI (Silicon On Insulator) substrate. The switch circuit 1 includes a common terminal 20 and individual terminals 30-1 and 30-2. The switch circuit 1 is connected to the common function circuit 2, the individual function circuit 3-1, and the individual function circuit 3-2 via the common terminal 20, the individual terminal 30-1, and the individual terminal 30-2, respectively. The switch circuit 1 selects one of the individual function circuits 3-1 and 3-2, and electrically connects the common function circuit 2 to the selected individual function circuit. The unselected individual function circuits are electrically insulated from the common function circuit 2. By operating the switch circuit 1, the individual function circuit electrically connected to the common function circuit 2 is switched. That is, the switch circuit 1 functions as an SPDT (Single Pole Double Throw) switch.

[0039] The common function circuit 2 is, for example, a transceiver antenna. The common function circuit 2 receives a high-frequency signal based on wireless communication from the outside. In addition, the common function circuit 2 transmits a high-frequency signal based on wireless communication to the outside. The individual function circuit 3-1 is, for example, a receiving unit that receives the high-frequency signal received by the transceiver antenna and performs processing such as reading data. The individual function circuit 3-2 is, for example, a transmitting unit that performs processing such as high-frequency signal conversion based on input data, and transmits it to the transceiver antenna and transmits it to the outside.

[0040] 1.2 Composition of the switching circuit

[0041] Figure 2 1 is a circuit diagram showing an example of the configuration of the switch circuit of the first embodiment. Figure 2 As shown, the switch circuit 1 further includes units 10-1 and 10-2, and a control circuit 100. The unit 10-1 is an internal circuit that switches the electrical connection state between the common terminal 20 and the individual terminal 30-1. The unit 10-2 is an internal circuit that switches the electrical connection state between the common terminal 20 and the individual terminal 30-2. The units 10-1 and 10-2 have substantially the same configuration.

[0042] The unit 10-1 includes switches 11-1, 12-1, and 13-1, a resistor 15-1, and an inductor 17-1. The switches 11-1, 12-1, and 13-1 each include a structure in which a plurality of MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are connected in series, and the plurality of MOSFETs have gate electrodes connected to a common wiring. The connection state of each of the switches 11-1, 12-1, and 13-1 is switched by a control signal supplied from the control circuit 100 via a wiring not shown.

[0043] The switch 11-1 has a first end connected to the common terminal 20 via the node N1, and a second end connected to the node N2-1. The switch 12-1 has a first end connected to the node N2-1, and a second end connected to the individual terminal 30-1 via the node N3-1. The switch 13-1 has a first end connected to the node N2-1, and a second end connected to the first end of the inductor 17-1. The resistor 15-1 has a first end connected to the node N2-1, and a second end connected to the individual terminal 30-1 via the node N3-1. The switch 12-1 and the resistor 15-1 are in a parallel relationship. The second end of the inductor 17-1 is grounded.

[0044] When viewed from the individual terminal 30-1, the impedance of the resistor 15-1, the switch 12-1 in the off state, the switch 13-1 in the on state, and the inductor 17-1 is substantially equal to the impedance of the individual functional circuit 3-1. For example, when an internal resistor of 50Ω is provided in the individual functional circuit 3-1, the total value of the resistance value of the resistor 15-1 and the switch 13-1 in the on state is designed to be 50Ω.

[0045] In addition, when the switch circuit 1 is operated in a high frequency band, when the common terminal 20 and the individual terminal 30-1 are electrically insulated by the unit 10-1, a power of about 25 dBm can be input to the individual terminal 30-1. The unit 10-1 is designed not to be damaged by the input power to the individual terminal 30-1. Specifically, for example, the resistor 15-1 can have a resistance of 10000 μm. 2 In addition, for example, the switch 12-1 can have a structure in which three or more MOSFETs having a gate width of about 4 mm are connected in series. In this case, the switch 12-1 in the off state can have a capacitance of about 0.4 pF. Since the impedance change caused by the capacitance of the switch 12-1 in the off state cannot be ignored in the high frequency band, it is compensated by the inductor 17-1.

[0046] The unit 10-2 includes switches 11-2, 12-2, and 13-2, a resistor 15-2, and an inductor 17-2. The switches 11-2, 12-2, and 13-2 each include a plurality of MOSFETs connected in series. The connection state of each of the switches 11-2, 12-2, and 13-2 is switched by a control signal supplied from the control circuit 100 via wiring (not shown).

[0047] The switch 11-2 has a first end connected to the common terminal 20 via the node N1, and a second end connected to the node N2-2. The switch 12-2 has a first end connected to the node N2-2, and a second end connected to the individual terminal 30-2 via the node N3-2. The switch 13-2 has a first end connected to the node N2-2, and a second end connected to the first end of the inductor 17-2. The resistor 15-2 has a first end connected to the node N2-2, and a second end connected to the individual terminal 30-2 via the node N3-2. The switch 12-2 and the resistor 15-2 are in a parallel relationship. The second end of the inductor 17-2 is grounded.

[0048] When viewed from the individual terminal 30-2, the impedance of the resistor 15-2, the switch 12-2 in the off state, the switch 13-2 in the on state, and the inductor 17-2 is substantially equal to the impedance of the individual functional circuit 3-2. For example, when an internal resistor of 50Ω is provided in the individual functional circuit 3-2, the total value of the resistance value of the resistor 15-2 and the switch 13-2 in the on state is designed to be 50Ω.

[0049] In addition, when the switch circuit 1 is operated in a high frequency band, when the common terminal 20 and the individual terminal 30-2 are electrically insulated by the unit 10-2, a power of about 25 dBm can be input to the individual terminal 30-2. The unit 10-2 is designed not to be damaged by the input power to the individual terminal 30-2. Specifically, for example, the resistor 15-2 can have a resistance of 10000 μm. 2 In addition, for example, the switch 12-2 can have a structure in which three or more MOSFETs having a gate width of about 4 mm are connected in series. In this case, the switch 12-2 in the off state can have a capacitance of about 0.4 pF. Since the impedance change caused by the capacitance of the switch 12-2 in the off state cannot be ignored in the high frequency band, it is compensated by the inductor 17-2.

[0050] The control circuit 100 controls the switches 11-1, 12-1, 13-1, 11-2, 12-2, and 13-2 by sending control signals to the switches 11-1, 12-1, 13-1, 11-2, 12-2, and 13-2. Specifically, different voltages are applied to the switches via wiring (not shown) to switch the electrical connection states between the individual function circuits 3-1 and 3-2 and the common function circuit 2.

[0051] 1.3 Operation of the switching circuit

[0052] Figure 3 : is a circuit diagram showing an example of a connection state of the switch circuit according to the first embodiment. Figure 3 The connection state shown corresponds to a state in which a signal is transmitted between the common terminal 20 and the individual terminal 30-1, and the individual terminal 30-2 is in operation as a terminal. Figure 3 , the individual terminal 30 - 1 is electrically connected to the common terminal 20 , and the individual terminal 30 - 2 is electrically insulated from the common terminal 20 . Figure 3 The arrows in show the main transmission paths of high-frequency signals input from each terminal.

[0053] right Figure 3 The state of each switch when the common terminal 20 shown is connected to the individual terminal 30 - 1 and the transmission path of the high-frequency signal input from each terminal will be described.

[0054] In the unit 10-1, the switches 11-1, 12-1 and 13-1 are respectively turned on, turned off and turned off. Figure 3 As shown by the arrows, the high frequency signal passes through the switches 11 - 1 and 12 - 1 and is transmitted to the individual terminal 30 - 1 . The same also applies when a high frequency signal is transmitted from the individual terminal 30 - 1 to the common terminal 20 .

[0055] In the unit 10-2, the switch 11-2 is turned off. Thus, the transmission of the high-frequency signal between the common terminal 20 and the individual terminal 30-2 is cut off. In addition, the switch 12-2 is turned off, and the switch 13-2 is turned on. Thus, the individual terminal 30-2 is terminated via the resistor 15-2, the switch 13-2, and the inductor 17-2.

[0056] Although not shown in the figure, when the common terminal 20 is electrically connected to the individual terminal 30-2, the connection states of the switches corresponding to the unit 10-1 and the unit 10-2 are reversed. That is, when the switches 11-2, 12-2, and 13-1 are in the on state, the switches 11-1, 12-1, and 13-2 are in the off state. In this case, the transmission of the high-frequency signal between the common terminal 20 and the individual terminal 30-1 is cut off, and the individual terminal 30-1 becomes a terminal via the resistor 15-1, the switch 13-1, and the inductor 17-1.

[0057] 1.4 Effects of the First Implementation

[0058] According to the first embodiment, the insertion loss of a high-frequency signal transmitted between terminals can be reduced. In addition, the reflection loss of a high-frequency signal input from an individual terminal not connected to a common terminal can be reduced. This effect will be described in detail.

[0059] The resistor 15-2 of the switch circuit 1 of the first embodiment is provided between the switch 11-2 and the individual terminal 30-2. Thus, when a signal is transmitted between the common terminal 20 and the individual terminal 30-1, a mismatch (Japanese: mismatch) occurs between the impedance of the node N2-2 side observed from the switch 11-2 in the disconnected state and the impedance of the node N1 side observed from the switch 11-2 in the disconnected state. Therefore, the signal transmitted between the common terminal 20 and the individual terminal 30-1 is reflected by the switch 11-2 in the disconnected state, thereby reducing the insertion loss of the signal. Similarly, the resistor 15-1 is provided between the switch 11-1 and the individual terminal 30-1. Thus, when a signal is transmitted between the common terminal 20 and the individual terminal 30-2, a mismatch occurs between the impedance of the node N2-1 side observed from the switch 11-1 in the disconnected state and the impedance of the node N1 side observed from the switch 11-1 in the disconnected state. Therefore, the signal transmitted between the common terminal and the individual terminal 30-2 is reflected by the switch 11-1 in the off state, so that the insertion loss of the signal is reduced. Figure 4 , Figure 5 ,as well as Figure 6 This effect will be described.

[0060] Figure 4 1 is a circuit diagram showing an example of an equivalent circuit of a switch circuit and an individual functional circuit according to the first embodiment. Figure 4 It is shown in Figure 3 The equivalent circuit of the switch circuit 1 and the individual functional circuit 3-2 in the connection state shown. Figure 4 In FIG. 1 , a switch in an on state is regarded as equivalent to a resistor, and a switch in an off state is regarded as equivalent to a capacitor, and they are described in a replaced manner. The individual function circuit 3 - 2 has a load resistor Load inside. The load resistor Load has an impedance of 50Ω, for example.

[0061] like Figure 4 As shown, when the individual terminal 30-1 is electrically connected to the common terminal 20, the switches 11-2 and 12-2 are in the off state, and the switch 13-2 is in the on state. The impedances of the switch 13-2 and the inductor 17-2 in the on state are both small. Therefore, the impedance of the circuit on the node N2-2 side observed from the switch 11-2 in the off state becomes sufficiently small, for example, less than 25Ω.

[0062] On the other hand, when transmitting between the common terminal 20 and the individual terminal 30-1, the impedance of the circuit on the node N1 side observed from the switch 11-2 is, for example, about 25 Ω. Therefore, when observed from the switch 11-2, an impedance mismatch occurs between the circuit on the node N1 side and the circuit on the node N2-2 side. As a result, near the node N2-2, the high-frequency signal passing through the switch 11-2 is reflected and returns to the normal circuit (Japanese: 正規の回路) side (common terminal 20 to individual terminal 30-1). Through this effect, the insertion loss associated with the inflow of the high-frequency signal into the unit 10-2 side can be reduced. In addition, although not shown in the figure, when the common terminal 20 is electrically connected to the individual terminal 30-2, the insertion loss can also be reduced by the effect of the reflection of the high-frequency signal at the switch 11-1.

[0063] Figure 5 is a diagram showing an example of the insertion loss in the switch circuit of the first embodiment. In Figure 5 In Figure 3 the insertion loss of the switch circuit 1 in the shown connection state is indicated by a solid line. In addition, in Figure 5 as a comparative example, in Figure 3 the insertion loss of the switch circuit without reflection in the shown connection state is indicated by a dashed line. The switch circuit of the comparative example corresponds to, for example, the case where the resistor 15-2 is connected between the switch 13-2 and the ground.

[0064] As Figure 5 shown, in the transmission of signals in the high-frequency band, the insertion loss of the circuit configuration with reflection is relatively reduced.

[0065] Figure 6 is a diagram showing an example of the maximum available gain (MAG: Maximum Available power Gain) in the switch circuit of the first embodiment. In Figure 6 In Figure 3 the insertion loss of the switch circuit 1 in the connection state is indicated by a solid line. In addition, in Figure 6 as a comparative example, in Figure 3 the maximum available gain of the switch circuit without reflection in the connection state is indicated by a dashed line.

[0066] As Figure 6 shown, the maximum available gain of the circuit configuration with reflection is always larger, and as the frequency increases, the difference is significant.

[0067] Moreover, the inductor 17-2 of the switch circuit 1 of the first embodiment is provided between the switch 13-2 and the ground. Thus, when the individual terminal 30-2 is insulated from the common terminal 20, the impedance of the individual functional circuit 3-2 side observed from the individual terminal 30-2 is matched (Japanese: integrated) with the impedance of the node N3-2 side observed from the individual terminal 30-2. Therefore, the signal sent from the individual functional circuit 3-2 is not easily reflected near the individual terminal 30-2, and the reflection loss of the signal is reduced. Similarly, the inductor 17-1 is provided between the switch 13-1 and the ground. Thus, when the individual terminal 30-1 is insulated from the common terminal 20, the impedance of the individual functional circuit 3-1 side observed from the individual terminal 30-1 is matched with the impedance of the node N3-1 side observed from the individual terminal 30-1. Therefore, the signal sent from the individual functional circuit 3-1 is not easily reflected near the individual terminal 30-1, and the reflection loss of the signal is reduced. Use Figure 4 as well as Figure 7 This effect will be described.

[0068] like Figure 4 As shown in FIG. 1 , when the individual terminal 30-2 is insulated from the common terminal 20, the switches 11-2 and 12-2 are in the off state, and the switch 13-2 is in the on state. The impedance of the switch 11-2 side in the off state viewed from the node N2-2 is sufficiently larger than the impedance of the switch 13-2 side in the on state viewed from the node N2-2. Therefore, when considering the path of the signal input from the individual terminal 30-2, the circuit on the switch 11-2 side viewed from the node N2-2 can be ignored.

[0069] Consider the impedance of the circuit in which the signal input from the individual terminal 30-2 is terminated by connecting the unit 10-2 to the ground. At this time, the impedance change caused by the capacitance of the switch 12-2 in the off state is compensated by the inductor 17-2, so that the same value as the impedance of the load resistance Load contained in the individual functional circuit 3-2 (for example, 50Ω) is obtained. Therefore, when viewed from the individual terminal 30-2, impedance matching occurs between the circuit on the side of the individual functional circuit 3-2 and the circuit on the side of the unit 10-2. Through this effect, the signal transmission efficiency from the individual terminal 30-2 to the unit 10-2 is optimized, and the reflection loss in the circuit boundary can be reduced. In addition, although the illustration is omitted, impedance matching also occurs when the common terminal 20 is electrically connected to the individual terminal 30-2. Through this effect, the signal transmission efficiency from the individual terminal 30-1 to the unit 10-1 is optimized, and the reflection loss in the circuit boundary can be reduced.

[0070] Figure 7 : is a graph showing an example of reflection loss in the switch circuit of the first embodiment. Figure 7 middle, Figure 3The reflection loss of the switch circuit 1 in the connection state is represented by a solid line. Figure 7 As a comparative example, Figure 3 The reflection loss of the switching circuit without the inductor 17-2 in the connection state is represented by a dotted line.

[0071] like Figure 7 As shown, the reflection loss of the circuit structure having the inductor 17-2 is reduced.

[0072] 1.5 First Modification

[0073] The switch circuit 1 of the first embodiment described above can be modified in various ways. Hereinafter, points different from the first embodiment will be mainly described.

[0074] A communication system SYS including a switch circuit 1A of the first variant includes n individual function circuits (n is an integer greater than or equal to 3) 3-1, 3-2, ..., and 3-n. The communication system SYS is, for example, a transceiver system capable of processing high-frequency signals of different frequencies in high-frequency signal wireless communication. The n individual function circuits 3-1, 3-2, ..., and 3-n are, for example, one of a receiving unit or a transmitting unit, and correspond to different frequencies. The switch circuit 1A electrically connects a common function circuit 2 and a selected individual function circuit 3-i (i∈{1, 2, ..., n}), and electrically insulates the common function circuit 2 from an unselected individual function circuit 3-j (j≠i|j∈{1, 2, ..., n}). That is, the switch circuit 1-1 functions as a SPnT (Single Pole n Throw) switch. The n individual function circuits 3-1, 3-2, ..., and 3-n include individual terminals 30-1, 30-2, ..., and 30-n, respectively.

[0075] Figure 8 FIG. 1 is a circuit diagram showing an example of the configuration of a switch circuit 1A according to a first variation. The switch circuit 1A switches the connection between a common terminal and n individual terminals. Figure 8 As shown, the switch circuit 1A includes cells 10 - 1 , 10 - 2 , . . . , and 10 - n . The cells 10 - 1 , 10 - 2 , . . . , and 10 - n are connected in parallel with respect to a node N1 receiving a wiring extending from a common terminal 20 .

[0076] Each of the units 10 - 1 , 10 - 2 , . . . , and 10 - n has substantially the same configuration as the units 10 - 1 and 10 - 2 in the first embodiment.

[0077] For example, the unit 10-n includes switches 11-n, 12-n, and 13-n, a resistor 15-n, and an inductor 17-n. The switches 11-n, 12-n, and 13-n each include a structure in which a plurality of MOSFETs having gate electrodes respectively connected to a common wiring are connected in series. The connection state of each of the switches 11-n, 12-n, and 13-n is switched by a control signal supplied from the control circuit 100 via a wiring not shown.

[0078] The switch 11-n has a first end connected to the common terminal 20 via the node N1, and a second end connected to the node N2-n. The switch 12-n has a first end connected to the node N2-n, and a second end connected to the individual terminal 30-n via the node N3-n. The switch 13-n has a first end connected to the node N2-n, and a second end connected to the first end of the inductor 17-n. The resistor 15-n has a first end connected to the node N2-n, and a second end connected to the individual terminal 30-n via the node N3-n. The switch 12-n and the resistor 15-n are in a parallel relationship. The second end of the inductor 17-n is grounded.

[0079] When viewed from the individual terminal 30-n, the impedance of the resistor 15-n, the switch 12-n in the off state, the switch 13-n in the on state, and the inductor 17-n is substantially equal to the impedance of the individual functional circuit 3-n. For example, when an internal resistor of 50Ω is provided in the individual functional circuit 3-n, the total value of the resistance value of the resistor 15-n and the switch 13-n in the on state is designed to be 50Ω.

[0080] The control circuit 100 controls the switches (11-1, 12-1, 13-1, 11-2, 12-2, 13-2, ..., 11-n, 12-n, and 13-n) included in the switch circuit 1. Specifically, by applying voltages of different magnitudes to the switches via wiring (not shown), the electrical connection states between the individual function circuits 3-1, 3-2, ..., 3-n and the common function circuit 2 are switched.

[0081] When the switch circuit 1A electrically connects the common terminal 20 to the selected individual terminal 30-i (i∈{1, 2, ..., n}), for the unit 10-i, the switches 11-i and 12-i are set to the on state, and the switch 13-i is set to the off state. For any other unit 10-j (j≠i|j∈{1, 2, ..., n}), the switches 11-j and 12-j are set to the off state, and the switch 13-j is set to the on state. In this way, the transmission of the high-frequency signal between the common terminal 20 and the selected individual terminal 30-i is achieved, and any non-selected individual terminal 30-j is made a terminal.

[0082] According to the configuration of the first modified example, one common function terminal can be switched to three or more individual function terminals.

[0083] 2. Second Implementation

[0084] Next, the second embodiment will be described. Hereinafter, the configuration different from the first embodiment will be mainly described.

[0085] 2.1 Composition of the switching circuit

[0086] Fig. 9 1 is a circuit diagram showing an example of the configuration of a switch circuit 1B according to the second embodiment. The switch circuit 1B includes switches 42 and 43, a resistor 45, and an inductor 47 in addition to the configuration of the switch circuit 1 according to the first embodiment. The switches 42 and 43 each include a configuration in which a plurality of MOSFETs having gate electrodes respectively connected to a common wiring are connected in series. The connection state of each of the switches 42 and 43 is switched by a control signal supplied from the control circuit 100 via a wiring not shown.

[0087] The switch 42 is arranged between the common terminal 20 and the node N1. That is, the switch 42 has a first end connected to the common terminal 20 and a second end connected to the node N1, and they are connected respectively. The switch 43 has a first end connected to the node N1 and a second end connected to the first end of the inductor 47. The resistor 45 has a first end connected to the common terminal 20 and a second end connected to the node N1. The switch 42 and the resistor 45 are in a parallel relationship. The second end of the inductor 47 is grounded.

[0088] The impedance of the resistor 45, the switch 42 in the off state, the switch 43 in the on state, and the inductor 47 as viewed from the common terminal 20 is substantially equal to the impedance of the common functional circuit 2. For example, when an internal resistance of 50Ω is provided in the common functional circuit 2, the total resistance value of the resistor 45 and the switch 43 in the on state is designed to be 50Ω.

[0089] When the common terminal 20 is electrically connected to the individual terminal 30-1 or 30-2, the switch 42 is turned on and the switch 43 is turned off. Thus, the high-frequency signal input from the common terminal 20 is transmitted to the node N1 through the switch 42 and then to the individual terminal 30-1 or 30-2. The same is true when the high-frequency signal is transmitted from the individual terminal 30-1 or 30-2 to the common terminal 20.

[0090] When the common terminal 20 is electrically insulated from any other terminal, the switch 42 is turned off and the switch 43 is turned on. In addition, the switch 11-1 of the unit 10-1 and the switch 11-2 of the unit 10-2 are both turned off. Thus, the high-frequency signal flowing out of the common terminal 20 is terminated via the resistor 45, the switch 43, and the inductor 47.

[0091] 2.2 Effects of the Second Implementation

[0092] According to the second embodiment, similar to the first embodiment, when a signal is transmitted between the common terminal 20 and the individual terminal 30-1, an impedance mismatch occurs in the switch 11-2 in the disconnected state, and the insertion loss of the high-frequency signal can be reduced by reflecting the signal. When a signal is transmitted between the common terminal 20 and the individual terminal 30-2, an impedance mismatch occurs in the switch 11-1 in the disconnected state, and the insertion loss of the high-frequency signal can be reduced by reflecting the signal. In addition, when the individual terminal 30-2 is insulated from the common terminal 20, impedance matching occurs at the individual terminal 30-2, and the signal sent from the individual functional circuit 3-2 is not easily reflected near the individual terminal 30-2, thereby reducing the reflection loss of the signal. When the individual terminal 30-1 is insulated from the common terminal 20, impedance matching occurs at the individual terminal 30-1, and the signal sent from the individual functional circuit 3-1 is not easily reflected near the individual terminal 30-1, thereby reducing the reflection loss of the signal.

[0093] According to the second embodiment, the common terminal 20 can be terminated when the common terminal 20 is electrically insulated from the individual terminals 30-1 and 30-2. When the common terminal 20 is terminated, the reflection loss of the high-frequency signal input from the common terminal 20 can be reduced.

[0094] 2.3 Second Modification

[0095] As a modification (second modification) of the switch circuit 1B described above, a modification to a SPnT switch that connects one common function circuit to a plurality of individual function circuits as in the first modification is considered. According to the configuration of the second modification, one common function terminal can be switched to three or more individual function terminals.

[0096] 3. Third Implementation

[0097] Next, a third embodiment will be described. Hereinafter, the configuration different from the first embodiment will be mainly described.

[0098] 3.1 Composition of the switching circuit

[0099] Fig.101 is a circuit diagram showing an example of the configuration of a switch circuit 1C according to the third embodiment. The switch circuit 1C includes matching circuits 50-1, 50-2, and 50-3 in addition to the configuration of the switch circuit 1 according to the first embodiment. The matching circuits 50-1, 50-2, and 50-3 have a function of adjusting the impedance within the switch circuit 1C and are circuits configured to suppress impedance mismatching caused by signal degradation due to insertion loss or the like.

[0100] The matching circuit 50-1 is connected between the unit 10-1 and the individual terminal 30-1. The matching circuit 50-1 includes an inductor 51-1 and a capacitor 52-1. The inductor 51-1 has a first end connected to the node N3-1 and a second end connected to the individual terminal 30-1 via the node N4-1. The capacitor 52-1 has a first end connected to the node N4-1 and a second end connected to the ground.

[0101] The matching circuit 50-2 is connected between the unit 10-2 and the individual terminal 30-2. The matching circuit 50-2 includes an inductor 51-2 and a capacitor 52-2. The inductor 51-2 has a first end connected to the node N3-2 and a second end connected to the individual terminal 30-2 via the node N4-2. The capacitor 52-2 has a first end connected to the node N4-2 and a second end connected to the ground.

[0102] The matching circuit 50-3 is connected between the common terminal 20 and the node N1. The matching circuit 50-3 includes an inductor 51-3 and a capacitor 52-3. The inductor 51-3 has a first end connected to the node N1 and a second end connected to the common terminal 20 via the node N4-3. The capacitor 52-3 has a first end connected to the node N4-3 and a second end connected to the ground.

[0103] 3.2 Effects of the Third Implementation

[0104] According to the configuration of the third embodiment, similar to the first embodiment, when a signal is transmitted between the common terminal 20 and the individual terminal 30-1, an impedance mismatch occurs in the switch 11-2 in the disconnected state, and the insertion loss of the high-frequency signal can be reduced by reflecting the signal. When a signal is transmitted between the common terminal 20 and the individual terminal 30-2, an impedance mismatch occurs in the switch 11-1 in the disconnected state, and the insertion loss of the high-frequency signal can be reduced by reflecting the signal. In addition, when the individual terminal 30-2 is insulated from the common terminal 20, impedance matching occurs at the individual terminal 30-2, and the signal sent from the individual functional circuit 3-2 is not easily reflected near the individual terminal 30-2, thereby reducing the reflection loss of the signal. When the individual terminal 30-1 is insulated from the common terminal 20, impedance matching occurs at the individual terminal 30-1, and the signal sent from the individual functional circuit 3-1 is not easily reflected near the individual terminal 30-1, thereby reducing the reflection loss of the signal.

[0105] Furthermore, according to the configuration of the third embodiment, it is possible to reduce the reflection loss of a signal input from a certain functional circuit that is insulated from other functional circuits. This effect will be described in detail.

[0106] In the configuration of the third embodiment, when the individual terminal 30-2 is insulated from the common terminal 20, a circuit is considered to terminate the signal input from the individual terminal 30-2. By connecting the matching circuit 50-2 between the unit 10-2 and the individual terminal 30-2, the impedance of the circuit including the switches 12-2 and 13-2, the resistor 15-2, the inductor 17-2, and the matching circuit 50-2 can be finely adjusted. Therefore, the impedance of the circuit on the unit 10-2 side observed from the individual functional circuit 3-2 can be matched with the impedance of the load resistor Load inside the individual functional circuit 3-2, including phase correction. As a result, the characteristic impedance of the signal input from the individual functional circuit 3-2 is matched with the impedance of the circuit that terminates the individual terminal 30-2, and it is not easy to generate reflection at the circuit boundary, which can reduce the reflection loss. In the case where the common terminal 20 is electrically connected to the individual terminal 30-2, the reflection loss at the circuit boundary when the signal is input from the individual terminal 30-1 to the unit 10-1 can be further reduced by the same effect.

[0107] Furthermore, the impedance of the signal input from the common terminal 20 can be finely adjusted by passing through the matching circuit 50-3. As a result, the signal transmission efficiency from the common terminal 20 to the unit 10-1 or 10-2 is optimized, and the reflection loss can be reduced.

[0108] 3.3 Third Modification

[0109] As a modification (third modification) of the switch circuit 1C described above, a SPnT switch connecting one common function circuit to a plurality of individual function circuits as in the first modification is considered. According to the configuration of the third modification, one common function terminal can be switched to three or more individual function terminals.

[0110] 4. Others

[0111] In the third embodiment described above, the matching circuits 50 - 1 , 50 - 2 , and 50 - 3 are applied to the switch circuit 1 of the first embodiment, but the present invention is not limited thereto. For example, the matching circuits 50 - 1 , 50 - 2 , and 50 - 3 may be applied to the switch circuit 1B of the second embodiment.

[0112] In the third embodiment described above, the matching circuit 50-1 includes both the inductor 51-1 and the capacitor 52-1, but the present invention is not limited thereto. For example, the matching circuit 50-1 may include at least one of the inductor 51-1 and the capacitor 52-1.

[0113] In the third embodiment described above, the matching circuit 50-2 includes both the inductor 51-2 and the capacitor 52-2, but the present invention is not limited thereto. For example, the matching circuit 50-2 may include at least one of the inductor 51-2 and the capacitor 52-2.

[0114] In the third embodiment described above, the matching circuit 50-3 includes both the inductor 51-3 and the capacitor 52-3, but the present invention is not limited thereto. For example, the matching circuit 50-3 may include at least one of the inductor 51-3 and the capacitor 52-3.

[0115] In the third embodiment, the switch circuit 1C includes the three matching circuits 50-1, 50-2, and 50-3, but the present invention is not limited thereto. For example, the switch circuit 1C may include at least one of the matching circuits 50-1, 50-2, and 50-3.

[0116] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the subject matter of the invention. These embodiments and their variations are included in the scope and subject matter of the invention, and are included in the invention described in the claims and the scope of their equivalents.

Claims

1. A switching circuit, comprising: A first terminal connected to the first node; A first switch having a first end connected to the first node and a second end connected to a second node; A second switch and a first resistor are connected in parallel between the second node and a third node; A second terminal connected to the third node; a third switch having a first terminal connected to the second node; A first inductor having a first end connected to the second end of the third switch and a second end connected to the ground; a fourth switch having a first end connected to the first node and a second end connected to a fourth node; A fifth switch and a second resistor are connected in parallel between the fourth node and the fifth node; A third terminal connected to the fifth node; a sixth switch having a first end connected to the fourth node; as well as The second inductor has a first end connected to the second end of the sixth switch and a second end grounded.

2. The switching circuit according to claim 1, Signals input or output from the first terminal, the second terminal, and the third terminal have a frequency of 600 MHz or more and 6 GHz or less.

3. The switch circuit according to claim 1, The first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch each include a plurality of transistors connected in series.

4. The switching circuit according to claim 1, It also has a control circuit. The control circuit is composed of: In a first action, the first switch, the second switch, and the sixth switch are set to an on state, and the third switch, the fourth switch, and the fifth switch are set to an off state; In the second operation, the third switch, the fourth switch, and the fifth switch are turned on, and the first switch, the second switch, and the sixth switch are turned off.

5. The switch circuit according to claim 1, further comprising: a seventh switch and a third resistor, connected in parallel between the first terminal and the first node; an eighth switch having a first end connected to the first node; and The third inductor has a first end connected to the second end of the eighth switch and a second end grounded.

6. The switch circuit according to claim 5, It also has a control circuit. The control circuit is composed of: In a first action, the first switch, the second switch, the sixth switch, and the seventh switch are set to an on state, and the third switch, the fourth switch, the fifth switch, and the eighth switch are set to an off state; In a second operation, the third switch, the fourth switch, the fifth switch, and the seventh switch are turned on, and the first switch, the second switch, the sixth switch, and the eighth switch are turned off; and In the third operation, the third switch, the sixth switch, and the eighth switch are turned on, and the first switch, the second switch, the fourth switch, the fifth switch, and the seventh switch are turned off.

7. The switch circuit according to claim 1, The device further includes at least one of a fourth inductor connecting the first terminal to the first node and a first capacitor having a first end connected to the first terminal and a second end connected to the ground.

8. The switch circuit according to claim 1, The device further includes at least one of a fifth inductor connecting the second terminal to the third node and a second capacitor having a first end connected to the second terminal and a second end connected to the ground.

9. The switch circuit according to claim 1, The device further includes at least one of a sixth inductor connecting the third terminal to the fifth node and a third capacitor having a first end connected to the third terminal and a second end connected to the ground.

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