Differential switching device and analog switch chip

Abstract

This invention provides a differential switch device and an analog switch chip, relating to the technical field of signal transmission. The differential switch device and analog switch chip provided by this invention include an analog switch and a control circuit connected to the analog switch in the switching unit of the differential switch device. The control circuit includes a logic operation unit and a voltage conversion unit connected to the control terminal of the analog switch. The logic operation unit is used to acquire the differential signal input from the input interface, perform logic operations based on the differential signal, and output a first voltage signal to the voltage conversion unit. The voltage conversion unit is used to convert the first voltage signal, output a second voltage signal corresponding to the first voltage signal, and input the second voltage signal to the control terminal of the analog switch to control the analog switch. During the control process, this helps to ensure the linearity of the analog switch, not only meeting users' requirements for different performance and reliability, but also helping to improve the transmission efficiency of high-frequency signals.

Description

Technical Field

[0001] This invention relates to the field of signal transmission technology, and in particular to a differential switching device and an analog switching chip. Background Technology

[0002] High-speed analog switches are widely used in high-frequency signal transmission. For example, in USB (Universal Serial Bus) and DP (DisplayPort) interfaces, high-speed analog switches are typically used to select and transmit data from different channels. As protocol speeds increase, the performance requirements for high-speed analog switches, such as bandwidth and on-resistance, also increase. Taking USB 3.1 and DP 1.3 protocols as examples, signal transmission rates reach 10Gbps and 8.1Gbps, respectively. Simultaneously, the protocols require that the common-mode voltage of the signal can vary within a certain range. This necessitates that high-speed analog switches possess the characteristic of maintaining a relatively stable on-resistance as the common-mode voltage changes.

[0003] In integrated circuit applications, CMOS transmission gates composed of NMOS and PMOS transistors are often used as analog switches. Their on-resistance can remain approximately stable as the input signal common-mode voltage changes. However, due to the relatively large parasitic capacitance, using transmission gates as switches in high-speed signal transmission is not conducive to improving bandwidth, thus affecting the overall performance of the transmission system. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a differential switching device and an analog switching chip to alleviate the above-mentioned technical problems.

[0005] In a first aspect, embodiments of the present invention provide a differential switch device, the differential switch device comprising: an input interface, a switch unit, and an output interface connected in sequence; the switch unit comprising an analog switch and a control circuit connected to the analog switch; wherein, the input terminal of the analog switch is connected to the input interface, the output terminal of the analog switch is connected to the output interface, and the control terminal of the analog switch is connected to the control circuit; the control circuit comprises a logic operation unit and a voltage conversion unit connected to the control terminal of the analog switch; the logic operation unit is used to acquire a differential signal input from the input interface, perform logic operations based on the differential signal, and output a first voltage signal to the voltage conversion unit; the voltage conversion unit is used to convert the first voltage signal, output a second voltage signal corresponding to the first voltage signal, and input the second voltage signal to the control terminal of the analog switch to control the analog switch.

[0006] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the analog switch includes a differential analog switch; the differential analog switch includes a first MOS transistor and a second MOS transistor; the gates of the first MOS transistor and the second MOS transistor are connected to the control terminal of the analog switch; one of the source and drain electrodes of the first MOS transistor and the second MOS transistor is connected to the input interface, and the other electrode is connected to the output interface.

[0007] In conjunction with the first possible implementation of the first aspect, this embodiment of the invention provides a second possible implementation of the first aspect, wherein the above-mentioned logic operation unit includes a differential-mode filter and a logic operation circuit; the input terminal of the differential-mode filter is connected to the input interface, and the output terminal of the differential-mode filter is connected to the logic operation circuit; the differential-mode filter is used to acquire the differential signal, filter the differential signal, and output the common-mode voltage signal corresponding to the differential signal to the logic operation circuit; the logic operation circuit is used to acquire the common-mode voltage signal, calculate the first voltage signal according to a preset reference voltage, calculation coefficients, and the common-mode voltage signal, and output it to the voltage conversion unit.

[0008] In conjunction with the second possible implementation of the first aspect, this embodiment of the invention provides a third possible implementation of the first aspect, wherein the differential switching device further includes a reference signal source connected to the logic operation circuit; the reference signal source is used to provide the reference voltage to the logic operation circuit.

[0009] In conjunction with the third possible implementation of the first aspect, this embodiment of the invention provides a fourth possible implementation of the first aspect, wherein the differential switching device further includes a voltage conversion circuit connected to the voltage conversion unit; the voltage conversion circuit is used to acquire the power supply voltage, convert the power supply voltage, and output the power supply for the voltage conversion unit.

[0010] In conjunction with the fourth possible implementation of the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein the voltage conversion circuit includes an oscillator and a charge pump connected in sequence, and the output terminal of the charge pump is connected to the voltage conversion unit for providing the power supply to the voltage conversion unit.

[0011] In conjunction with the fifth possible implementation of the first aspect, this embodiment of the invention provides a sixth possible implementation of the first aspect, wherein the charge pump is further connected to the reference signal source; the reference signal source is further used to provide a reference signal to the charge pump.

[0012] In conjunction with the fifth possible implementation of the first aspect, this embodiment of the invention provides a seventh possible implementation of the first aspect, wherein the charge pump is further connected to the logic operation circuit; the logic operation circuit is further configured to provide the first voltage signal to the charge pump as a reference signal.

[0013] In conjunction with the second possible implementation of the first aspect, this embodiment of the invention provides an eighth possible implementation of the first aspect, wherein the differential switching device further includes a digital control unit connected to the logic operation circuit and the voltage conversion unit; the digital control unit is used to adjust the calculation coefficients.

[0014] Secondly, embodiments of the present invention also provide an analog switch chip, wherein the analog switch chip is configured with the differential switch device described in the first aspect.

[0015] The embodiments of the present invention bring the following beneficial effects:

[0016] The differential switch device and analog switch chip provided in this invention include an analog switch and a control circuit connected to the analog switch in the switching unit of the differential switch device. The control circuit includes a logic operation unit and a voltage conversion unit connected to the control terminal of the analog switch. The logic operation unit is used to acquire the differential signal input from the input interface, perform logic operations based on the differential signal, and output a first voltage signal to the voltage conversion unit. The voltage conversion unit is used to convert the first voltage signal, output a second voltage signal corresponding to the first voltage signal, and input the second voltage signal to the control terminal of the analog switch to control the analog switch. During the control process, the differential switch device can be configured through the logic operation unit and the voltage conversion unit to meet the performance requirements of wider bandwidth and lower on-resistance, while keeping the control signal of the analog switch relatively constant, thereby helping to ensure the linearity of the analog switch. This not only meets the user's requirements for different performance and reliability, but also helps to improve the transmission efficiency of high-frequency signals. Furthermore, compared to existing technologies, this invention can also acquire the differential signal obtained from the high-frequency signals of dual analog switches or multiple analog switches after differential processing, calculate the common-mode voltage, and feed it back to the control electrode of the analog switch. In addition, while improving anti-interference capability, it can also remove the influence of process, voltage and temperature changes on the common-mode voltage, making the output signal more stable.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a differential switch device provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of another differential switching device provided in an embodiment of the present invention;

[0022] Figure 3 A waveform diagram provided for an embodiment of the present invention;

[0023] Figure 4 A control schematic diagram of a digital control unit provided in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of another differential switching device provided in an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of signal change provided in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of another differential switching device provided in an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a differential switching device and an analog switch chip, which can meet the requirements of high-speed analog switches with large bandwidth and low on-resistance as signal transmission rates increase. It also allows for flexible configuration of the differential switching device and meets the new performance requirements arising from the continuous increase in signal transmission rates.

[0029] To facilitate understanding of this embodiment, a differential switching device disclosed in this embodiment of the invention will first be described in detail.

[0030] In one possible implementation, embodiments of the present invention provide a differential switching device, specifically, as shown in the example below. Figure 1 The schematic diagram of a differential switching device shown includes: an input interface 10, a switching unit 20, and an output interface 30 connected in sequence.

[0031] The switching unit 20 includes an analog switch 201 and a control circuit 202 connected to the analog switch 201.

[0032] Specifically, the input terminal of the analog switch 201 is connected to the input interface 10, the output terminal of the analog switch is connected to the output interface 30, and the control terminal of the analog switch is connected to the control circuit 202.

[0033] The control circuit 202 includes a logic operation unit 203 and a voltage conversion unit 204 connected to the control terminal of the analog switch;

[0034] The logic operation unit 203 is used to acquire the differential signal input from the input interface, perform logic operations based on the differential signal, and output the first voltage signal to the voltage conversion unit.

[0035] The voltage conversion unit 204 is used to convert the first voltage signal, output the second voltage signal corresponding to the first voltage signal, and input the second voltage signal to the control terminal of the analog switch to control the analog switch.

[0036] In practical applications, the differential switching device in this embodiment of the invention is mostly used for transmitting high-frequency signals, for example, as a high-frequency signal transmission interface in electronic devices, to select and transmit high-frequency signals from different channels. Through the control process of the logic operation unit 203 and the voltage conversion unit 204, adaptive control of the bandwidth and on-resistance of the differential switching device can be achieved, thereby ensuring the transmission efficiency of high-frequency signals.

[0037] The differential switch device provided in this embodiment of the invention includes an analog switch and a control circuit connected to the analog switch in the switching unit. The control circuit includes a logic operation unit and a voltage conversion unit connected to the control terminal of the analog switch. The logic operation unit is used to acquire the differential signal input from the input interface, perform logic operations based on the differential signal, and output a first voltage signal to the voltage conversion unit. The voltage conversion unit is used to convert the first voltage signal, output a second voltage signal corresponding to the first voltage signal, and input the second voltage signal to the control terminal of the analog switch to control the analog switch. During the control process, the differential switch device can be configured through the logic operation unit and the voltage conversion unit to meet the performance requirements of wider bandwidth and lower on-resistance, while keeping the control signal of the analog switch relatively constant, thereby helping to ensure the linearity of the analog switch. This not only meets the user's requirements for different performance and reliability, but also helps to improve the transmission efficiency of high-frequency signals.

[0038] In practical applications, differential processing is typically used to transmit high-frequency signals in order to improve anti-interference capabilities during high-frequency signal transmission. Therefore, the input interface typically receives a differential high-frequency signal. The analog switch described above is a differential analog switch. Specifically, in this embodiment, the differential analog switch includes a first MOSFET and a second MOSFET; the gates of the first and second MOSFETs are connected to the control terminal of the analog switch; one of the source and drain electrodes of the first and second MOSFETs is connected to the input interface, and the other electrode is connected to the output interface.

[0039] For ease of understanding, Figure 1 On this basis, Figure 2 A schematic diagram of another differential switching device is also shown, such as... Figure 2 As shown, the differential analog switch includes a first MOSFET and a second MOSFET, namely... Figure 2 The first MOS transistor M1 and the second MOS transistor M2 are described in this embodiment of the invention. In this embodiment, the first MOS transistor M1 and the second MOS transistor M2 are NMOS transistors. The gates of the first MOS transistor M1 and the second MOS transistor M2 are connected to the control terminal of the analog switch. In this embodiment, when the NMOS transistor is used as a switch, its source and drain can be interchanged. Therefore, in this embodiment, one of the source and drain electrodes of the first MOS transistor and the second MOS transistor is connected to the input interface, and the other electrode is connected to the output interface. Figure 2In this embodiment, the source is connected to the input interface and the drain is connected to the output interface as an example. In other embodiments, the connection between the source and drain of the first MOSFET and the second MOSFET can be set according to the actual use. The models of the first MOSFET and the second MOSFET can also be set according to the actual use. This embodiment of the invention does not limit this.

[0040] Furthermore, the logic operation unit in this embodiment of the invention includes a differential-mode filter and a logic operation circuit; wherein, Figure 2 The differential filter 205 and logic operation circuit 206 are shown in the figure.

[0041] Specifically, the input terminal of the differential-mode filter 205 is connected to the input interface, and the output terminal of the differential-mode filter is connected to the logic operation circuit 206. The differential-mode filter 205 is used to acquire the differential signal, filter the differential signal, and output the corresponding common-mode voltage signal to the logic operation circuit 206. The logic operation circuit 206 is used to acquire the common-mode voltage signal, calculate a first voltage signal based on a preset reference voltage, calculation coefficients, and the common-mode voltage signal, and output it to the voltage conversion unit.

[0042] In practical applications, the aforementioned differential-mode filters typically employ differential-mode low-pass filters, where... Figure 2 In this diagram, Vin+ and Vin- represent the differential signals of the input high-frequency signal, and Vout+ and Vout- are the corresponding output signals of the high-frequency signal. After the high-frequency signal is input to the switching device, the differential signals Vin+ and Vin- are first filtered by a differential-mode filter to obtain the common-mode voltage signal of the differential signal. In this embodiment of the invention, the common-mode voltage signal is represented by Vcm. The explanation is based on an example where the high-frequency signal is a sine wave. Figure 3 A waveform diagram is shown, specifically, Figure 3 The diagram shows the waveforms of the input differential signals Vin+ and Vin-, and their common-mode voltage signal Vcm. Assuming Vin+ and Vin- are sinusoidal signals with opposite phases, a maximum voltage of VH, and a minimum voltage of VL, the common-mode voltage signal Vcm is (VH+VL) / 2. If the bandwidth of the differential low-pass filter is 3dB, which is much smaller than the frequency of the input differential signal, a relatively stable common-mode voltage signal Vcm can be obtained.

[0043] The logic operation circuit calculates a first voltage signal based on a preset reference voltage, calculation coefficients, and a common-mode voltage signal. The reference voltage and calculation coefficients can be pre-stored in a preset storage device or adjusted and controlled according to actual usage. Therefore, the differential switching device in this embodiment further includes a reference signal source connected to the logic operation circuit; that is, Figure 2The reference signal source 40 shown is used to provide a reference voltage to the logic operation circuit.

[0044] Specifically, the reference voltage provided by this reference signal source typically does not change with parameters such as process, voltage, and temperature, thus ensuring the stability of the reference voltage. In this embodiment of the invention, Vref represents the reference voltage. The reference voltage Vref and the common-mode voltage signal Vcm are used together as inputs to the logic operation circuit. The logic operation circuit performs logic operations on the reference voltage Vref and the common-mode voltage signal Vcm to obtain the first voltage signal Vbias. The relationship between the three voltages is expressed as follows:

[0045]

[0046] Where k and n are the calculation coefficients.

[0047] Furthermore, to facilitate the adjustment of the calculated coefficients, the differential switching device in this embodiment of the invention further includes a digital control unit connected to the logic operation circuit and the voltage conversion unit; this digital control unit is used to adjust the calculated coefficients. Specifically, Figure 4 A control schematic diagram of a digital control unit is shown, such as... Figure 4 As shown, it includes a digital control unit 401, a logic operation circuit 206, and a voltage conversion unit 204, and their connection relationship is as follows: Figure 4 As shown, the calculation coefficients k and n can be adjusted separately through the digital control unit.

[0048] Furthermore, the first voltage signal Vbias obtained through the above logical operation is used as the input voltage of the voltage conversion unit. In specific implementation, the voltage conversion unit is equipped with a voltage conversion circuit. The second voltage signal can be obtained by performing voltage conversion through the voltage conversion circuit.

[0049] In practical use, the voltage conversion circuit of the voltage conversion unit usually requires a power supply from an external circuit to start. Therefore, the differential switch device in this embodiment of the invention also includes a voltage conversion circuit connected to the voltage conversion unit. The voltage conversion circuit is used to obtain the power supply voltage, convert the power supply voltage, and output the power supply for the voltage conversion unit.

[0050] Specifically, such as Figure 2 As shown, the voltage conversion circuit includes an oscillator 207 and a charge pump 208 connected in sequence. The output terminal of the charge pump 208 is connected to the voltage conversion unit to provide power to the voltage conversion unit.

[0051] In practical use, the signal Vosc generated by the oscillator drives the charge pump. The input of the charge pump is connected to the power supply voltage, and the output is connected to the voltage conversion unit. Through the conversion action of the charge pump, the power supply voltage can be boosted to obtain a voltage signal Vcp that is higher than the power supply voltage. This ensures that the power supply voltage meets the voltage range required by the voltage conversion circuit included in the voltage conversion unit, thereby enabling the entire circuit to work normally.

[0052] Furthermore, the charge pump in this embodiment of the invention can also be connected to the aforementioned reference signal source; for ease of understanding, Figure 5 A schematic diagram of another differential switching device is also shown, such as... Figure 5 As shown, with Figure 2 The difference lies in that the charge pump 208 is connected to the reference signal source 40 and can acquire the reference voltage Vref shown by the reference signal source 40. Therefore, the reference signal source described above in this embodiment of the invention is also used to provide a reference signal to the charge pump.

[0053] In practical implementation, the reference voltage Vref output by the reference signal source can be used as the reference voltage of the charge pump. This ensures that the voltage signal Vcp obtained by the charge pump is proportional to the reference voltage Vref, guaranteeing that the voltage signal Vcp remains relatively stable despite changes in process, voltage, and temperature parameters. The voltage signal Vcp generated by the charge pump serves as the power supply for the voltage conversion unit. Combined with the input voltage of the voltage conversion unit, i.e., the first voltage signal Vbias, the gate voltage Vg of the first and second MOSFETs in the differential analog switch can be obtained. This Vg can be expressed as:

[0054]

[0055] It can be seen that when fixed calculation coefficients k and n are selected, Vg-Vcm in the above formula is a fixed value, which ensures that the gate voltage and source common-mode voltage of the NMOS transistor are relatively stable. In this embodiment of the invention, taking the first MOS transistor M1 and the second MOS transistor M2 as NMOS transistors as examples, the source and drain of an NMOS transistor are structurally symmetrical. In this embodiment, when the NMOS transistor is used as a switch, the source and drain are interchangeable. For ease of description, in this embodiment, one end of Vin is referred to as the source, therefore, Vcm is called the source common-mode voltage signal.

[0056] Since Vg is obtained in the power supply domain of the voltage signal Vcp, and the voltage signal Vcp is higher than the power supply voltage, Vg can be higher than the power supply voltage.

[0057] Taking Vdd as an example to illustrate, when the source common-mode voltage Vcm of the NMOS transistor is close to the supply voltage Vdd, since Vg > supply voltage Vdd, and Vg-Vcm can still remain relatively stable and not limited by the supply voltage Vdd, the gate-source voltage of the NMOS transistor can always maintain a relatively large value when the source common-mode voltage varies in the range of 0 to Vdd. This reduces the on-resistance of the switch, thereby improving the bandwidth of the entire analog switch and ensuring the transmission quality of high-speed signals.

[0058] For ease of understanding, Figure 6 A schematic diagram of signal changes is shown, specifically, Figure 6 The vertical axis represents voltage, and the horizontal axis represents time. Figure 6 The diagram shows the time-varying gate voltage Vg, input signal Vin (including Vin+ and Vin-), and source common-mode voltage Vcm of the first MOSFET M1 and the second MOSFET M2, as shown below. Figure 6 As shown, it can be seen that as the source common-mode voltage Vcm of the input signal Vin changes, the gate voltage Vg will also change accordingly adaptively. At the same time, the difference between Vg and Vcm remains unchanged, thus ensuring the relative constant on-resistance of the NMOS transistor.

[0059] further, Figure 4 The digital control unit shown in the diagram adjusts the calculation coefficients k and n of the logic operation circuit and voltage conversion unit to obtain different gate-source common-mode voltages, enabling flexible control of the bandwidth and on-resistance of the analog switch. The logic operation circuit can also be selectively shut down under the control of the digital control unit, allowing the voltage signal Vcp to be directly applied to the NMOS transistor as its gate voltage. In this case, the gate voltage does not change with Vcm. This is suitable for situations where the input signal common-mode voltage changes little. The on-resistance will change somewhat with Vcm, but as long as Vg is slightly higher than the high level VH of the input signal (usually the NMOS threshold voltage Vth), full-swing signal transmission can still be achieved. Furthermore, because part of the circuit (the logic operation circuit) is shut down, the overall power consumption of the switching device can be reduced.

[0060] Furthermore, the charge pump in this embodiment of the invention can also be connected to the above-mentioned logic operation circuit; in this case, the logic operation circuit is also used to provide a first voltage signal to the charge pump as a reference signal. For ease of understanding, Figure 7 A schematic diagram of another differential switching device is also shown, such as... Figure 7 As shown, Figure 7In the circuit, the charge pump 208 is connected to the logic operation circuit 206. The first voltage signal Vbias output by the logic operation circuit is directly used as an input of the charge pump, so that the output voltage of the charge pump is proportional to Vbias. At this time, the output voltage of the charge pump can be directly used for the gate voltage Vg of the NMOS transistor. That is, the conversion coefficient of the voltage conversion circuit in the voltage conversion unit is set to 1, so that Vg follows the change of Vcm.

[0061] Furthermore, when the common-mode voltage signal Vcm of the input differential signal is always low and the signal swing is very small, the high-voltage signal Vcp provided by the charge pump can be directly removed, so that the entire circuit is in the power supply domain of the power supply voltage Vdd. In this implementation, since there is no need for an oscillator and a charge pump, the power consumption of the overall switching device circuit can be greatly reduced.

[0062] The specific configuration of the charge pump can be set according to the actual usage, and the embodiments of the present invention do not impose any restrictions on this.

[0063] In summary, the differential switching device provided in this invention is primarily designed for high-speed data signals (Gbps and above), i.e., high-frequency signals. It performs low-pass filtering on the differential signal corresponding to the input high-frequency signal to obtain the common-mode voltage signal for subsequent processing. This achieves both relative constancy between the gate voltage and the source common-mode voltage, as well as low on-resistance and high bandwidth. Furthermore, it provides a flexible configuration option for different on-resistance values ​​for various applications, allowing users to strike a balance between performance and reliability requirements. In addition, in applications where constant on-resistance is not required, a portion of the circuitry can be shut down to select a gate voltage that does not change with the input signal, thereby saving power.

[0064] Furthermore, based on the above embodiments, this embodiment of the invention also provides an analog switch chip, which is configured with the above-mentioned differential switch device. For example, the differential switch device is set at the transmission interface position of the analog switch chip for selecting and transmitting high-frequency signals from different channels, etc.

[0065] The analog switch chip provided in this embodiment of the invention has the same technical features as the differential switch device provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0066] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the analog switch chip described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0067] The differential switch device and analog switch chip computer program product provided in the embodiments of the present invention include a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the previous embodiments. For specific implementation, please refer to the foregoing embodiments, which will not be repeated here.

[0068] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0069] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0070] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0071] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A differential switching device, characterized by The differential switching device includes: an input interface, a switching unit, and an output interface connected in sequence; The switching unit includes an analog switch and a control circuit connected to the analog switch; The input terminal of the analog switch is connected to the input interface, the output terminal of the analog switch is connected to the output interface, and the control terminal of the analog switch is connected to the control circuit. The control circuit includes a logic operation unit and a voltage conversion unit connected to the control terminal of the analog switch; The logic operation unit is used to acquire the differential signal input by the input interface, perform logic operations based on the differential signal, and output a first voltage signal to the voltage conversion unit; The voltage conversion unit is used to convert the first voltage signal, output a second voltage signal corresponding to the first voltage signal, and input the second voltage signal to the control terminal of the analog switch to control the analog switch; The analog switch includes a differential analog switch; The differential analog switch includes a first MOSFET and a second MOSFET; the gates of the first MOSFET and the second MOSFET are connected to the control terminal of the analog switch. Of the source and drain of the first MOS transistor and the second MOS transistor, one electrode is connected to the input interface and the other electrode is connected to the output interface; The logic operation unit includes a differential mode filter and logic operation circuitry; The input terminal of the differential filter is connected to the input interface, and the output terminal of the differential filter is connected to the logic operation circuit. The differential-mode filter is used to acquire the differential signal, filter the differential signal, and output the common-mode voltage signal corresponding to the differential signal to the logic operation circuit. The logic operation circuit is used to acquire the common-mode voltage signal, calculate the first voltage signal according to the preset reference voltage, calculation coefficients and the common-mode voltage signal, and output it to the voltage conversion unit; The logic operation circuit performs logic operations on the reference voltage and the common-mode voltage signal to obtain the first voltage signal. The relationship between the three voltages is expressed as follows: Wherein, Vref represents the reference voltage, Vcm represents the common-mode voltage signal, Vbias represents the first voltage signal, k and n are calculation coefficients, and the reference voltage and the calculation coefficients are pre-stored in a preset storage device, and the calculation coefficients are adjusted by a digital control unit; The voltage conversion unit converts the first voltage signal to obtain the gate voltage Vg of the first MOS transistor and the second MOS transistor included in the differential analog switch. Vg is expressed as: When fixed calculation coefficients k and n are selected, Vg-Vcm is a fixed value, making the gate voltage and source common-mode voltage of the first MOS transistor and the second MOS transistor included in the differential analog switch relatively stable.

2. The differential switching device of claim 1, wherein, The differential switching device also includes a reference signal source connected to the logic operation circuit; The reference signal source is used to provide the reference voltage to the logic operation circuit.

3. The differential switching device of claim 2, wherein, The differential switching device further includes a voltage conversion circuit connected to the voltage conversion unit; The voltage conversion circuit is used to obtain the power supply voltage, convert the power supply voltage, and output the power supply for the voltage conversion unit.

4. The differential switching device of claim 3, wherein, The voltage conversion circuit includes an oscillator and a charge pump connected in sequence. The output terminal of the charge pump is connected to the voltage conversion unit to provide power to the voltage conversion unit.

5. The differential switching device of claim 4, wherein, The charge pump is also connected to the reference signal source; The reference signal source is also used to provide a reference signal to the charge pump.

6. The differential switching device of claim 4, wherein, The charge pump is also connected to the logic operation circuit; The logic circuit is also used to provide the first voltage signal as a reference signal to the charge pump.

7. The differential switching device according to claim 1, characterized in that, The differential switching device further includes a digital control unit connected to the logic operation circuit and the voltage conversion unit; The digital control unit is used to adjust the calculated coefficients.

8. An analog switch chip, characterized in that, The analog switch chip is configured with the differential switch device according to any one of claims 1 to 7.

Images