CN113872575A

CN113872575A - Extensible radio frequency switch circuit

Info

Publication number: CN113872575A
Application number: CN202111456045.6A
Authority: CN
Inventors: 战吉超; 陆建华
Original assignee: Nanjing Suirui Technology Co ltd
Current assignee: Nanjing Suirui Technology Co ltd
Priority date: 2021-12-02
Filing date: 2021-12-02
Publication date: 2021-12-31

Abstract

An expandable radio frequency switch circuit comprises a radio frequency switch circuit and a logic control circuit, wherein the radio frequency switch circuit receives the control of the logic control circuit and provides a transmission channel for a radio frequency signal; the logic control circuit is used for controlling the channel switching of the radio frequency switch circuit and comprises a control bit, an address bit and a mirror image bit, wherein the control bit is used for controlling the channel switching of the radio frequency switch circuit; the address bit is used for selecting the radio frequency switch circuit; and the mirror image position is used for controlling the sequence turning of the channels of the radio frequency switch circuit. The expandable radio frequency switch circuit can be directly expanded into a single-pole multi-throw switch by the least number of devices, and is suitable for various multi-channel switching scenes without being realized by cascade connection.

Description

Extensible radio frequency switch circuit

Technical Field

The present invention relates to radio frequency switch circuits, and more particularly, to an expandable radio frequency switch circuit.

Background

In rf microwave systems, multi-channel switching, such as multi-bank filter switching, is usually required. The method for implementing multi-channel switching in the prior art comprises the following steps:

1) multiple Single Pole Double Throw (SPDT) switch cascades are selected. In a radio frequency system, generally, a small insertion loss and a small size are required, and therefore, in a scheme for realizing the radio frequency system, a small insertion loss and a small size of a switching device per se and a small number of devices to be used are desired. As shown in fig. 1, the method for switching 8 sets of filters (N1-N8) implemented by single-pole double-throw (S1-S14) switches requires 14 SPDT switches in total, and each switch needs to be controlled, where P1 and P2 are rf input/output ports, respectively, and RFC is a common port of the single-pole double-throw switch. The working principle of the scheme is that the switch of the corresponding branch is opened through the control of the switch state, and one of the branches of the filter is selected. If the filter N1 is selected, the switches S1-S6 are all turned on for a total of 6 switches to be cascaded. The scheme has the obvious defects of complex scheme, more switches, large system area and high cost; due to the large number of cascaded switches, the insertion loss is also large. And the number of switches increases further as the number of filters that need to be switched increases.

2) Selecting a corresponding multi-branch switch, as shown in fig. 2, a general radio frequency switch only includes a control bit, and has no expandability and poor compatibility; in the multi-path switching application, in order to not increase the control bits, the two multi-branch switches need the same control, i.e., RF1 is connected with RF1 and … …, RF4 is connected with RF4, and the chip needs to be placed by turning 180 °, so that there is radio frequency crossing in the PCB wiring radio frequency lines. And the application scenes are various, and the development cost and the time cost of a new product are very high.

Disclosure of Invention

In order to solve the defects of the prior art, the invention aims to provide an expandable radio frequency switch circuit, which can directly expand a switch into more branches for use and solve the problem of wiring intersection; the single-pole n-throw switch can be directly expanded into a single-pole n-throw switch (n = 1-16) with the least number of devices, and the defects of large insertion loss, more devices, large area, high cost, poor universality and the like in a multi-channel switching scene in the traditional scheme are overcome.

To achieve the above object, the present invention provides an expandable rf switch circuit, which comprises an rf switch circuit and a logic control circuit, wherein,

the radio frequency switch circuit receives the control of the logic control circuit and provides a transmission channel for a radio frequency signal;

the logic control circuit is used for controlling the channel switching of the radio frequency switch circuit and comprises a control bit, an address bit and a mirror image bit, wherein,

the control bit is used for controlling the channel switching of the radio frequency switch circuit;

the address bit is used for selecting the radio frequency switch circuit;

and the mirror image position is used for controlling the sequence turning of the channels of the radio frequency switch circuit.

Furthermore, the radio frequency switch circuit is a single-pole four-throw radio frequency switch circuit; the logic control circuit comprises 4-bit control bits (C0-C3), 2-bit address bits (A0, A1) and a mirror image bit (M0).

In order to achieve the above object, the present invention further provides an expandable rf switch chip, which includes the expandable rf switch circuit.

In order to achieve the above object, the present invention further provides a filter switching circuit, which includes the above expandable rf switch chip.

Further, the filter switching circuit comprises 4 groups of filters and 2 expandable radio frequency switch chips.

Further, the filter switching circuit comprises 8 groups of filters and 4 expandable radio frequency switch chips.

Furthermore, the filter switching circuit comprises 16 groups of filters and 8 expandable radio frequency switch chips.

The expandable radio frequency switch circuit has the following beneficial effects:

1) the application requirement of switching different numbers of branches can be realized by one chip, the universality is strong, the investment of manpower, period and capital cost in research and development and mass production of a plurality of chips is solved, and the expandability design has absolute advantages;

2) when the multi-branch switching is applied, the number of chips and the control scheme are greatly simplified, so that the design is simplified, the area is reduced, the insertion loss of a system is reduced, the system performance is improved, the method can be effectively used in the application scene of the multi-branch switching, and the traditional implementation scheme is replaced.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of a circuit for implementing multi-group filter switching by cascading a plurality of single-pole double-throw switches;

FIG. 2 is a schematic diagram of a circuit for implementing multi-bank filter switching by a multi-branch switch in the prior art;

FIG. 3 is a block diagram of a single pole, four throw scalable RF switch circuit according to the present invention;

FIG. 4 is a block diagram of a 4 bank filter switching circuit according to the present invention;

FIG. 5 is a block diagram of an 8 bank filter switching circuit according to the present invention;

fig. 6 is a block diagram of a 16 bank filter switching circuit according to the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The invention relates to an expandable radio frequency switch circuit, which aims at the problems that a plurality of single-pole double-throw (SPDT) switches are selected and cascaded layer by layer in the existing multi-path switching application scheme, namely one is divided into two, two is divided into four, four is divided into eight … …, the number of devices is large, the insertion loss is large (the cascade insertion loss is directly added), the cost is high, the area is large, the system scheme is complex, and the problems of poor compatibility and wiring cross exist due to the selection of the single-pole multi-throw switches.

Example 1

The expandable radio frequency switch circuit of the invention comprises a radio frequency switch circuit and a logic control circuit, wherein,

and the radio frequency switch circuit receives the control of the logic control circuit and provides a transmission channel for the radio frequency signal.

And the logic control circuit is used for controlling the channel switching of the radio frequency switch circuit.

In the embodiment of the invention, the logic control circuit comprises a control bit, an address bit and a mirror image bit, wherein,

a control bit for controlling channel switching of the RF switch circuit, wherein the m-bit control bit at most supports 2^m

Way switching (m is a positive integer greater than 1).

Address bits for selecting the active chip.

And the mirror image position is used for controlling the switching branches to turn over in sequence.

The non-switch control bits (address bits and mirror image bits) can be respectively realized by grounding or suspending the PCB to be 0 and 1 (0 refers to low level and 1 refers to high level), and lead wires are not needed, so that the board distribution is convenient.

Example 2

Fig. 3 is a block diagram of a single-pole four-throw scalable rf switch circuit according to the present invention, as shown in fig. 3, the single-pole four-throw scalable rf switch circuit of the present invention comprises a single-pole four-throw switching rf circuit and a logic control circuit, wherein,

the logic control circuit comprises 4-bit control bits C0-C3, 2-bit address bits A0, A1, a mirror bit M0,

the control bits C0-C3 are used for controlling the channel switching of the switch, and the m control bits at most support 2^mWay switches, address bits A0, A1 are used to select the active chip. The non-switch control bits can be respectively realized by grounding or suspending the PCB to be 0 and 1 (0 refers to low level and 1 refers to high level), no lead is needed, and the board distribution is convenient. The single-pole four-throw switch can complete the switching of the RF1-RF4 branches by controlling the single-pole four-throw switch per se and needs 2 bits, 4-bit control bits are designed and reserved, so that the switching of 16 branches can be expanded to the maximum, the same control bits of chips are directly connected during expansion, and the control bits of the whole scheme cannot be increased.

The mirror image position M0 is used for controlling the switching branches to be sequentially turned over, if a group of control bits is in M0= '0', corresponding RF1-RF4 branches are turned on, and if M0= '1', corresponding RF4-RF1 branches are turned on, so that the switching branches corresponding to the same branch position can be turned on by adopting the same group of control bits when the PCB is laid out.

In the embodiment of the invention, at most 2 × N branches can be switched by using N extensible radio frequency switch circuits, so that a plurality of groups of switches can be switched by using fewer circuits; that is, 2 scalable rf switch circuits are used to implement 4 filter switches, 4 scalable rf switch circuits are used to implement 8 filter switches, … …, N scalable rf switch circuits are used to implement at most 2 × N filter switches; all branches only need one-level cascade connection, and because the insertion loss and the cascade connection are linearly related, the insertion loss performance introduced by the switch can be minimized.

Although the present invention employs a single-pole four-throw switch, 4-bit control bits, and 2-bit address bits, the method of expansion is not limited thereto, and the same expansion method can be applied to a single-pole a-throw switch, b-bit control bits, and c-bit address bits. (a, b, c are each an integer > 1)

Example 3

Fig. 4 is a block diagram of a 4-group filter switching circuit according to the present invention, and as shown in fig. 4, the 4-group filter switching circuit of the present invention includes 2 scalable RF switch chips composed of the single-pole four-throw scalable RF switch circuit of embodiment 2, the chips are arranged as shown in fig. 4, the RF wiring does not need to cross, and the RF branch connection relations satisfy RF1-RF4, RF2-RF3, RF3-RF2, and RF4-RF1 for the two corresponding chips. The switch states are configured as follows, and the S1 and S2 address bits A1A 0 are both configured as "00"; the mirror image bits M0 of the S1 and S2 are respectively thrown to '0' and '1'; the 4 channels need to use two control bits of C0 and C1, C2 and C3 are used for fixing the electric potential, S1 and S2 share the control bits, namely the two chips C0 and C1 are respectively and correspondingly connected, and the 4 groups of filter switching circuits only use two control bits of C0 and C1. With the above configuration, switching of 4 channels can be realized.

Example 4

Fig. 5 is a block diagram of 8 sets of filter switching circuits according to the present invention, and as shown in fig. 5, the 8 sets of filter switching circuits according to the present invention include 4 scalable RF switch chips formed by the single-pole four-throw scalable RF switch circuit of embodiment 2, the chips are placed as shown in fig. 5, the RF wiring does not need to cross, and the RF branch connection relations satisfy RF1-RF4, RF2-RF3, RF3-RF2, and RF4-RF1 for the corresponding two chips. The switch states are configured as follows, the S1 and S2 address bits A1A 0 are both configured as "00", and the S3 and S4 address bits A1A 0 are both configured as "01"; the mirror image position M0 of the S1 and S3 switches is thrown to be 0 ', and the mirror image position M0 of the S2 and S4 switches is thrown to be 1'; the 8 channels need to use three control bits of C0, C1 and C2, C3 is used for giving a fixed potential, S1, S2, S3 and S4 share the control bits, namely all chips C0, C1 and C2 are respectively and correspondingly connected, and 8 groups of filter switching circuits only use the three control bits of C0, C1 and C2. With the above configuration, switching of 8 channels can be realized.

Example 5

Fig. 6 is a block diagram of a 16-bank filter switching circuit according to the present invention, and as shown in fig. 6, the 16-bank filter switching circuit of the present invention includes 8 scalable RF switch chips formed by the single-pole four-throw scalable RF switch circuit of embodiment 2, the chips are arranged as shown in fig. 6, the RF wiring does not need to cross, and the RF branch connection relations satisfy RF1-RF4, RF2-RF3, RF3-RF2, and RF4-RF1 for the two corresponding chips. The switch states are configured as follows, and S1 (S2) to S7 (S8) address bits A1A 0 are sequentially configured to be '00', '01', '10', '11'; the mirror image position M0 of the S1, S3, S5 and S7 switches is thrown to be 0 ', and the mirror image position M0 of the S2, S4, S6 and S8 switches is thrown to be 1'; the 16 channels need to use four control bits of C0, C1, C2 and C3, all chips share the control bits, namely all chips C0, C1, C2 and C3 are correspondingly connected respectively, and the system only uses four control bits of C0, C1, C2 and C3. With the above configuration, switching of 16 channels can be realized.

Example 6

The present invention also provides an expandable rf switch chip, including the expandable rf switch circuit described in

embodiments

1 and 2 above.

The invention relates to an extensible single-pole four-throw (SP 4T) switch chip and a multi-path extension technical scheme, which mainly increase address bits and mirror image bits, so that a switch can be directly extended into more branches for use, and the problem of wiring intersection is solved. The circuit can be directly expanded into a single-pole n-throw switch (n = 1-16) with the least number of devices, and is suitable for various multi-channel switching scenes without being realized through cascade connection; the method has the mirror image function, can solve the problem that the radio frequency wiring of the PCB needs to be crossed, has the advantages of low cost, small area, simple application scheme, good insertion loss performance and the like, and provides a high-compatibility solution for a filter bank and other multi-channel switching scenes. In conclusion, the invention solves the defects of large insertion loss, more devices, large area, high cost, poor universality and the like of the traditional scheme in a multi-channel switching scene.

The foregoing details are directed to single-pole, four-throw, scalable rf switch circuits and chips, and are equally applicable to the design of single-pole, multiple-throw, scalable rf switch circuits and chips.

Those of ordinary skill in the art will understand that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A scalable radio frequency switch circuit comprising, a radio frequency switch circuit and a logic control circuit, wherein,

the address bit is used for selecting the radio frequency switch circuit;

2. The scalable radio frequency switch circuit according to claim 1, wherein the radio frequency switch circuit is a single-pole four-throw radio frequency switch circuit; the logic control circuit comprises 4-bit control bits (C0-C3), 2-bit address bits (A0, A1) and a mirror image bit (M0).

3. An expandable radio frequency switch chip, characterized in that it comprises the expandable radio frequency switch circuit of claim 1 or 2.

4. A filter switching circuit, comprising the scalable radio frequency switch chip of claim 3.

5. The filter switching circuit of claim 4, comprising 4 sets of filters, 2 of said scalable radio frequency switch chips.

6. The filter switching circuit of claim 4, comprising 8 sets of filters, 4 of said scalable radio frequency switch chips.

7. The filter switching circuit of claim 4, comprising 16 sets of filters, 8 of said scalable radio frequency switch chips.