CN117639755A - Radio frequency switch unit, radio frequency switch network and circuit structure - Google Patents
Radio frequency switch unit, radio frequency switch network and circuit structure Download PDFInfo
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- CN117639755A CN117639755A CN202311752300.0A CN202311752300A CN117639755A CN 117639755 A CN117639755 A CN 117639755A CN 202311752300 A CN202311752300 A CN 202311752300A CN 117639755 A CN117639755 A CN 117639755A
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Abstract
The application provides a radio frequency switch unit, a radio frequency switch network and a switch path formed by a plurality of cascaded switch transistors, wherein the grid electrodes of the switch transistors are electrically connected to a grid voltage through a grid resistor, the body electrodes are electrically connected to a body voltage through an integral electrode resistor, and the source/drain electrodes of the switch transistors and the source/drain electrodes of adjacent switch transistors are sequentially connected; at least one side source/drain electrode of the switching transistor positioned at the end part of the switching path is connected to the source/drain electrode of the adjacent switching transistor, and the source/drain electrode of the switching transistor and the source/drain electrodes of other switching transistors are electrically connected to source/drain voltages through a bias resistor; and the other side source/drain electrode is used as a target port of the switch path, disconnected from the source/drain voltage and used for being connected to a line crossing node of a circuit network.
Description
Technical Field
The present disclosure relates to the field of radio frequency technologies, and in particular, to a radio frequency switching unit and a radio frequency switching network.
Background
The conventional rf switch mostly adopts a structure of cascade connection of multiple MOS transistors, please refer to fig. 1, which is a schematic structural diagram of the conventional rf switch. The radio frequency switch comprises a plurality of cascaded NMOS transistors, and the gates of the transistors pass through a gate resistor R G Connected to the gate voltage V G The source and drain of the transistor pass through resistor R D Connected to source-drain voltage V D Body electrode passing resistor R B Connected to the bulk voltage (e.g., ground in fig. 1).
A switching network may be formed by a plurality of rf switches as shown in fig. 1, but this tends to result in a drop in the actual output power, affecting the switching performance.
Disclosure of Invention
The invention provides a radio frequency switch unit, a radio frequency switch network and a circuit structure, which can improve the performance of the radio frequency switch unit in an access circuit network and reduce the chip layout area of the radio frequency switch circuit.
The invention proposes a radio frequency switching unit comprising: the switching circuit is composed of a plurality of cascaded switching transistors, the grid electrodes of the switching transistors are electrically connected to grid voltage through a grid resistor, the body electrodes of the switching transistors are electrically connected to body voltage through a body electrode resistor, and the source/drain electrodes of the switching transistors and the source/drain electrodes of adjacent switching transistors are sequentially connected; at least one side source/drain electrode of the switching transistor positioned at the end part of the switching path is connected to the source/drain electrode of the adjacent switching transistor, and the source/drain electrode of the switching transistor and the source/drain electrodes of other switching transistors are electrically connected to source/drain voltages through a bias resistor; and the other side source/drain electrode is used as a target port of the switch path, disconnected from the source/drain voltage and used for being connected to a line crossing node of a circuit network.
Optionally, the voltage at the crossover node is affected by another circuit branch other than the radio frequency switch unit connected to the crossover node.
The application also provides a radio frequency switching network comprising: at least three radio frequency switching units as described above; the target ports of the switching paths of the radio frequency switching units are mutually connected to form a cross node of the radio frequency switching network.
Optionally, the other end of the switch path of the radio frequency switch unit is used as a signal input end or a signal output end.
Optionally, the signal input end and the signal output end of the radio frequency switch network are both connected in series with a blocking capacitor.
Optionally, the switch network includes n radio frequency switch units, and when the radio frequency switch network works normally, at least 2 radio frequency switch units are respectively in different working states, and n is greater than or equal to 3.
Optionally, at least 1 radio frequency switch unit is used as an input signal path, and the rest radio frequency switch units are respectively used as switchable output signal paths; when one of the input signal paths is conducted with any one of the radio frequency switch units serving as an output signal path, the other radio frequency switch units are turned off, and the output power of the switch network is as follows: pout= (N-1) [2 ]] 2 /Zo+[2*(Vth)] 2 Wherein Vdd is the source-drain voltage, vth is the threshold voltage of the switching transistors, N is the number of switching transistors cascaded by the rf switching unit, zo is the characteristic impedance of the rf operating environment in which the rf switching unit is located, and is typically 50 ohms.
The present application also provides a circuit structure, comprising: a radio frequency switching unit as claimed in any preceding claim, and at least one circuit branch; one end of the circuit branch is connected to a target port of the radio frequency switch unit to form a cross node; the voltage at the crossover node is affected by the circuit branch.
Optionally, the circuit branch has an equivalent direct current path from the crossover node to another voltage source.
Optionally, in the working state of the circuit structure, the voltage requirements of the circuit branch and the radio frequency switch unit on the crossing node are different.
The source/drain electrode and the source/drain electrode of the switch transistor on one side of the end part of the radio frequency switch unit are disconnected from source/drain electrode voltage for connecting to other circuits, and are used for being connected into a circuit network, and the switch transistor is used as a target port of the switch passage and is used for being connected to a line crossing node of the circuit network. Because the source/drain electrode is disconnected from the source drain voltage, the voltage at the line crossing node is not influenced by the bias voltage of the radio frequency switch unit, when the radio frequency switch unit is in the off state, the source drain voltage is in the proper bias voltage Vdd, other switch transistors in the radio frequency switch unit are ensured to be in the off state, and therefore the performance of the radio frequency switch transistor in the switch network is improved.
Furthermore, as the connection between the target port and the source drain voltage is disconnected, the stable closing state of the radio frequency switch unit is realized by reducing the bias resistance, and the chip area can be reduced without adding an additional isolation device.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a RF switch unit;
FIG. 2 is a schematic diagram of a RF switch network;
FIG. 3 is a schematic diagram of a RF switch network;
FIG. 4 is a schematic diagram of a RF switch unit according to an embodiment of the present application;
fig. 5 is a schematic structural diagram of a radio frequency switch network according to an embodiment of the present application;
fig. 6 is a schematic diagram illustrating an operating state of a radio frequency switch network according to an embodiment of the present application;
fig. 7 is a schematic diagram of a circuit structure according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application. The various embodiments described below and their technical features can be combined with each other without conflict.
Referring to fig. 2, in one implementation, an rf switch network formed by the rf switch units shown in fig. 1 is used.
When the radio frequency switch units 10, 12 are in the state of "ON", the conduction is conductedIn the on state, the radio frequency switch unit 11 is turned "off" and the RF signal flow is as shown in the figure. The radio frequency switch network usually connects a blocking capacitor C in series with the signal input and output terminals BLK But each radio frequency switching unit is typically directly connected to the network cross point VM.
According to the bias condition of the switching state of the rf switch unit, vds, on=0, and Vds, off=vdd, V of the rf switch unit 11 in the state of fig. 2 D,Off Vdd, i.e. the voltage at the S terminal of the rf switch unit 11 is Vdd; and V of the RF switch unit 12 D,on =0, the voltage at the S terminal of the rf switch unit 12 is 0; similarly, the voltage at the D terminal of the RF switch unit 10 is V D,on =0; the three rf switch unit connections have a cross point VM where the voltage at VM is affected by the D terminal of the rf switch unit 10 and the S terminals of the rf switch units 11 and 12. Because the states of the rf switch unit 11 and the rf switch unit 12 are different, the voltage requirements at VM are in conflict, and the voltage requirements have different bias voltage requirements, so that the S terminal voltage of the rf switch unit 11 is affected by the S terminal voltage of the rf switch unit 12 and pulled down, the turn-off states of all switch transistors in the rf switch unit 11 are affected, and the overall output power is greatly reduced.
For example, each rf switch unit has N switch transistors, in the case shown in fig. 2, pout=n×2×vth] 2 and/Zo, where Zo is the characteristic impedance of the rf operating environment in which the rf switch unit is located, and is typically 50 ohms.
Whereas the output power of a single rf switching unit (e.g., fig. 1), pout=n [2 ] (vdd+vth)] 2 /Zo. Thus, it can be seen that in the case of fig. 2, the output power of the formed rf switching network is far lower than that of the individual rf switching units, and the output power is greatly attenuated.
Please refer to fig. 3, which is a schematic diagram of another rf switch network.
In order to avoid voltage conflict at VM, capacitors, such as C1 and C2, may be connected in series at the connection of each radio frequency switch unit of VM to isolate bias voltages at each end of the connection of each radio frequency switch unit, so as to avoid conflict, and make the switch states of each switch branch mutually independent. However, due to the larger capacitor size, more capacitors are required to be added to a relatively complex radio frequency switch network, which results in increased chip area and increased cost.
In order to solve the above problems, the present application proposes a new structure of a radio frequency switch unit.
Fig. 4 is a schematic structural diagram of a radio frequency switch unit according to an embodiment.
In this embodiment, the radio frequency switch unit 100 includes: a switch path composed of a plurality of cascaded switch transistors M, wherein the gates of the switch transistors M pass through a gate resistor R G Electrically connected to the gate voltage V G The body poles all pass through an integral pole resistor R B The voltage source is electrically connected to a bulk voltage, which is ground in this embodiment, and may be other voltages in other embodiments.
The source and drain electrodes of the switching transistors M and the source and drain electrodes of the adjacent switching transistors are sequentially connected; at least one side source-drain electrode of the switching transistor M1 positioned at the end part of the switching path is connected to the source-drain electrode of the adjacent switching transistor, and the source-drain electrodes of the other switching transistors are connected through a bias resistor R D Electrically connected to source-drain voltage V D The method comprises the steps of carrying out a first treatment on the surface of the The other side source drain electrode S of the switching transistor M1 at the end part of the switching path is used as a target port of the switching path and is connected with the source drain voltage V D Disconnection, for connection to a line crossover node of a circuit network.
In particular, it is particularly suitable for the voltage at the crossover node to be influenced by another circuit branch, other than the radio frequency switching unit 100, connected to the crossover node.
The embodiment of the present application further provides a radio frequency switch network, which includes at least two radio frequency switch units 100 as described in the embodiment of fig. 4. The destination ports of the switching paths of the respective rf switching units 100 are connected to each other to form a crossover node of the rf switching network.
Fig. 5 is a schematic structural diagram of a radio frequency switch network according to an embodiment of the present application.
The radio frequency switching network comprises at least three radio frequency switching units 100a, 100b and 100c as described in the embodiment of fig. 4; the destination ports of the switching paths of the radio frequency switching units are connected to each other to form a crossover node VM of the radio frequency switching network. Each radio frequency switching unit acts as a branch of the radio frequency switching network.
The other end of the switch path of the radio frequency switch unit is used as a signal input end or a signal output end. Specifically, the rf switch unit 100a is used as a signal input branch, the drain D of the switch transistor M1 at one end of the switch path is used as a signal output terminal, connected to the crossover node VM, disconnected from the source-drain voltage VD, and the source S of the switch transistor at the other end of the switch path is used as a signal input terminal; the rf switch units 100b and 100c serve as signal output branches, and the source S of the switch transistor M1 at one end of the switch path serves as a signal input terminal, is connected to the crossover node VM, and is disconnected from the source-drain voltage VD, and the drain D of the transistor at the other end is connected to the source-drain voltage VD as a signal output terminal.
In this embodiment, the signal input terminal (source S of the switching transistor on the input side of the RF switching unit 100 a) and the signal output terminal (drain D of the switching transistor on the output side of the RF switching units 100b and 100C) of the whole RF switching network are connected in series with a blocking capacitor C BLK To improve the isolation performance of the whole radio frequency switch network.
Fig. 6 is a schematic diagram illustrating an operating state of the rf switch network shown in fig. 5.
The rf switch units 100a and 100c are turned ON and turned OFF, and the rf switch network 100b is turned OFF and turned ON, and the rf signal is output through the rf switch network 100a and the rf switch unit 100 c.
In order to meet the above operation state, the radio frequency switching network 100a and the radio frequency switching network 100c meet the bias condition Vds, on=0; setting the source-drain voltages VD of the rf switch network 100a and the rf switch network 100c to V D ＝0。
The rf switch network 100b needs to satisfy the bias condition Vds, off=vdd, and the source-drain voltage V of the rf switch unit 100b needs to be set D Set to Vdd.
Since the source voltage vs=vd=0 of the switching transistor M1 in the rf switching unit 100a and the drain voltage vd=vd=0 of the switching transistor M1 of the rf switching unit 100c, the voltage at the crossing node VM is 0.
And the drain voltage vd=v of the switching transistor M1 of the rf switching unit 100b D The drain voltage vs=0, while the bias voltage of the switching transistor M1 is asymmetric, it may be ensured that the sources and drains of other transistors in the cell are all connected to the bias voltage Vdd, and are in an OFF state, thereby ensuring that the switching leg of the rf switching unit 100b is in an "OFF" state.
When the input signal path is turned on with any one of the rf switch units as the output signal path, the other rf switch units are turned off, for example, fig. 6, at this time, the output power pout= (N-1) ×2×2 (vdd+vth) of the rf switch network] 2 /Zo+[2*(Vth)] 2 Wherein Vdd is the source-drain voltage, vth is the threshold voltage of the switching transistors, N is the number of switching transistors cascaded by the rf switching unit, zo is the characteristic impedance of the rf operating environment in which the rf switching unit is located, and is typically 50 ohms.
In other embodiments, the switching network may include n radio frequency switching units, where one radio frequency switching unit is used as an input signal path, and the remaining n-1 radio frequency switching units are respectively used as switchable output signal paths, and target ports of the n radio frequency switching units are connected; wherein n is greater than or equal to 3.
In the above embodiment, the input/output ends of the transistors of the radio frequency switch units connected to the network crossover node are disconnected from the source-drain voltage, so that the voltage requirements of the radio frequency switch units at the crossover node are not in conflict under different switch states, the radio frequency switch units in the OFF state are ensured to be kept in the OFF state, and the output power of the radio frequency switch network is improved.
The embodiment of the application also provides a circuit structure, which comprises the radio frequency switch unit in the embodiment and at least one circuit branch. One end of the circuit branch is connected to a target port of the radio frequency switch unit to form a cross node VM; the voltage at the crossover node VM is affected by the circuit branch.
In some embodiments, the circuit branch has an equivalent direct current path from the crossover node to another voltage source. For example, the circuit branch may include an inductance or other dc path in series between the crossover node and ground.
Referring to the embodiment of fig. 7, two rf switch units 100 are used, and one circuit branch 200. In this embodiment, the circuit branch 200 is a radio frequency impedance matching network with a band-pass filter function. Since the inductive device has a path to ground, the dc potential of the crossover node VM is "0". And just because the S terminal of the first switching transistor in the rf switching unit 100 is not forcibly set with a bias voltage, it can be biased to 0 along with VM direct current, so that the bias states of all other switching transistors in the unit are in safe and stable OFF states, and a larger and stable rf output power is obtained in a smaller circuit layout area.
In other embodiments, the circuit branch and the radio frequency switch unit have different voltage requirements at the crossover node in the operating state of the circuit structure. Since the target port of the radio frequency switching unit is disconnected from the source-drain voltage, the voltage at the crossover node is not affected by said source-drain voltage for providing the bias voltage, so that the radio frequency switching unit can operate in a normal bias state.
The foregoing embodiments are merely examples of the present application, and are not intended to limit the scope of the patent application, so that all equivalent structures or equivalent processes using the descriptions and the drawings of the present application, such as the combination of technical features of the embodiments, or direct or indirect application to other related technical fields, are included in the scope of the patent protection of the present application.
Claims (10)
1. A radio frequency switching unit comprising:
the switching circuit is composed of a plurality of cascaded switching transistors, the grid electrodes of the switching transistors are electrically connected to grid voltage through a grid resistor, the body electrodes of the switching transistors are electrically connected to body voltage through a body electrode resistor, and the source/drain electrodes of the switching transistors and the source/drain electrodes of adjacent switching transistors are sequentially connected;
at least one side source/drain electrode of the switching transistor positioned at the end part of the switching path is connected to the source/drain electrode of the adjacent switching transistor, and the source/drain electrode of the switching transistor and the source/drain electrodes of other switching transistors are electrically connected to source/drain voltages through a bias resistor; and the other side source/drain electrode is used as a target port of the switch path, disconnected from the source/drain voltage and used for being connected to a line crossing node of a circuit network.
2. The radio frequency switching unit according to claim 1, wherein the voltage at the crossover node is affected by another circuit branch outside the radio frequency switching unit connected to the crossover node.
3. A radio frequency switching network, comprising: at least three radio frequency switching units according to any of claims 1 to 2;
the target ports of the switching paths of the radio frequency switching units are mutually connected to form a cross node of the radio frequency switching network.
4. A radio frequency switching network according to claim 3, wherein the other end of the switching path of the radio frequency switching unit, other than the crossover node, is used as a signal input or signal output.
5. The radio frequency switching network of claim 4, wherein the signal input and the signal output of the radio frequency switching network are each connected in series with a blocking capacitor.
6. The radio frequency switching network according to claim 4, wherein the switching network comprises n radio frequency switching units, wherein at least 2 radio frequency switching units are respectively in different working states when the radio frequency switching network works normally, and n is not less than 3.
7. The radio frequency switching network according to claim 6, wherein at least 1 radio frequency switching unit of the n radio frequency switching units is used as an input signal path, and the remaining radio frequency switching units are respectively used as switchable output signal paths; when one of the input signal paths is conducted with any one of the radio frequency switch units serving as an output signal path, the other radio frequency switch units are turned off, and the output power of the switch network is as follows:
Pout＝(N-1)*[2*(Vdd+Vth)] 2 /Zo+[2*(Vth)] 2 wherein Vdd is the source-drain voltage, vth is the threshold voltage of the switching transistors, N is the number of switching transistors cascaded by the rf switching unit, zo is the characteristic impedance of the rf working environment in which the rf switching unit is located.
8. A circuit structure, comprising: the radio frequency switching unit of any of claims 1 to 2, and at least one circuit branch;
one end of the circuit branch is connected to a target port of the radio frequency switch unit to form a cross node;
the voltage at the crossover node is affected by the circuit branch.
9. The circuit structure of claim 8, wherein the circuit branch has an equivalent direct current path from the crossover node to another voltage source.
10. The circuit arrangement of claim 8, wherein in an operational state of the circuit arrangement, the voltage requirements at the crossover node are different for the circuit branch and the radio frequency switching unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311752300.0A CN117639755A (en) | 2023-12-19 | 2023-12-19 | Radio frequency switch unit, radio frequency switch network and circuit structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311752300.0A CN117639755A (en) | 2023-12-19 | 2023-12-19 | Radio frequency switch unit, radio frequency switch network and circuit structure |
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| Publication Number | Publication Date |
|---|---|
| CN117639755A true CN117639755A (en) | 2024-03-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202311752300.0A Pending CN117639755A (en) | 2023-12-19 | 2023-12-19 | Radio frequency switch unit, radio frequency switch network and circuit structure |
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| CN (1) | CN117639755A (en) |
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- 2023-12-19 CN CN202311752300.0A patent/CN117639755A/en active Pending
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