CN111431514B

CN111431514B - Broadband buffering analog switch circuit and integrated circuit

Info

Publication number: CN111431514B
Application number: CN202010525961.XA
Authority: CN
Inventors: 林辉浪; 蒋宇辰; 宋民
Original assignee: Shenzhen Siglent Technologies Co Ltd
Current assignee: Shenzhen Siglent Technologies Co Ltd
Priority date: 2020-06-11
Filing date: 2020-06-11
Publication date: 2020-09-29
Anticipated expiration: 2040-06-11
Also published as: CN111431514A

Abstract

The application discloses broadband buffering analog switch circuit and broadband buffering analog switch integrated circuit, including first input buffer circuit, feedback switch circuit and broadband switch circuit. The first input buffer circuit comprises a low-frequency input circuit, a high-frequency input buffer circuit and a feedback circuit, wherein high-frequency signals, direct currents and/or low-frequency signals input into the broadband buffering analog switch circuit are buffered through the high-frequency input buffer circuit and then are respectively output to the feedback switch circuit and the broadband switch circuit, and then the broadband switch circuit and the feedback switch circuit respectively provide the broadband buffering analog switch circuit with the switching function of the input signals. Because the feedback circuit provides loop negative feedback for the low-frequency input circuit, the high-frequency input buffer circuit and the broadband switch circuit, the broadband buffer analog switch circuit has a stable static working state, and further the broadband buffer analog switch circuit has excellent switching performance under direct current, low frequency and high frequency.

Description

Broadband buffering analog switch circuit and integrated circuit

Technical Field

The invention relates to the technical field of integrated circuit design, in particular to a broadband buffer analog switch circuit and an integrated circuit.

Background

The switch mainly performs a signal switching function in a signal link, and the switch implemented by using characteristics of an analog device is called an analog switch. An analog switch is an electronic switch that can connect and disconnect two signals. Analog switches function primarily as on or off signals in electronic devices. The analog switch has the characteristics of low power consumption, high speed, no mechanical contact, small volume, long service life and the like, so the analog switch is widely applied to the fields of industry, instruments and meters, medical treatment, consumer electronics, communication, automobile systems and the like. For the analog switch applied to high-speed data transmission, the bandwidth is an extremely important index, and if the bandwidth of the analog switch is low, the data transmission signal is seriously damaged, and even the data transmission cannot be performed. Colloquially, it is how fast a signal passes through an analog switch without distortion. Common analog switches include gallium arsenide switches, PIN diode switches, bootstrap switches, etc., and such switches generally have a very high analog bandwidth, but do not have the switching function of direct current and low frequency. The buffer amplifier is a voltage follower, has high input impedance and low output impedance characteristics, and is commonly used for special functions such as isolation, impedance matching, circuit output capability enhancement and the like. The buffer analog switch is a device or a circuit which is provided with a buffer amplifier and an analog switch at the same time, has the characteristics of high output impedance and low output impedance, and can complete the signal switching function in a signal link. The bandwidth of the existing integrated broadband buffer amplifier is limited, and is generally less than 1 GHz.

Disclosure of Invention

The application provides a broadband buffering analog switch circuit, solves the technical problem that the bandwidth of a broadband buffering analog switch is narrow in the prior art.

According to a first aspect, an embodiment provides a wideband buffered analog switch circuit, comprising a first input buffer circuit, a feedback switch circuit, and a wideband switch circuit; the first input buffer circuit comprises an input end of the input buffer circuit, a first output end of the input buffer circuit and a feedback input end of the input buffer circuit; the input end of the input buffer circuit is used as a first input end of the broadband buffer analog switch circuit, the first output end of the input buffer circuit is respectively connected with the feedback switch circuit and the broadband switch circuit, and the feedback input end of the input buffer circuit is connected with the feedback switch circuit; the first input buffer circuit comprises a low-frequency input circuit, a high-frequency input buffer circuit and a feedback circuit; the low-frequency input circuit comprises a low-frequency input circuit input end, a feedback circuit connecting end and a low-frequency input circuit output end; the input end of the low-frequency input circuit is connected with the input end of the input buffer circuit of the first input buffer circuit, the connecting end of the feedback circuit is connected with the feedback circuit, and the output end of the low-frequency input circuit is connected with the high-frequency input buffer circuit; the low-frequency input circuit is used for buffering and amplifying direct current and/or low-frequency signals input by a first input end of the broadband buffering analog switch circuit and then outputting the signals to the high-frequency input buffer circuit; the high-frequency input buffer circuit comprises a high-frequency input buffer circuit input end, a low-frequency input circuit connecting end and a high-frequency input buffer circuit output end; the input end of the high-frequency input buffer circuit is connected with the input end of the input buffer circuit of the first input buffer circuit, the connecting end of the low-frequency input circuit is connected with the low-frequency input circuit, and the output end of the high-frequency input buffer circuit is connected with the first output end of the input buffer circuit of the first input buffer circuit; the high-frequency input buffer circuit is used for buffering a high-frequency signal input by a first input end of the broadband buffer analog switch circuit and a direct current and/or low-frequency signal output by a low-frequency circuit output end of the low-frequency input circuit and then respectively outputting the high-frequency signal and the direct current and/or low-frequency signal to the feedback switch circuit and the broadband switch circuit; the feedback circuit comprises a first connection end of the feedback circuit and a second connection end of the feedback circuit; the first connecting end of the feedback circuit is connected with the connecting end of the feedback circuit of the low-frequency input circuit, and the second connecting end of the feedback circuit is connected with the feedback input end of the input buffer circuit of the first input buffer circuit; the feedback circuit is used for providing loop negative feedback for the low-frequency input circuit, the high-frequency input buffer circuit and the broadband switch circuit so as to stabilize the static working voltage of the broadband buffer analog switch circuit;

the broadband switch circuit comprises a first broadband switch circuit input end and a broadband switch circuit output end; the input end of the first broadband switch circuit is connected with the first output end of the input buffer circuit of the first input buffer circuit, and the output end of the broadband switch circuit is used as the output end of the broadband buffer analog switch circuit; the broadband switch circuit is used for providing a switching function for an electric signal transmitted between a first input end of the broadband buffering analog switch circuit and an output end of the broadband switch circuit;

the feedback switch circuit comprises a first connecting end, a second connecting end and a first common end; the first connection end is connected with a first output end of an input buffer circuit of the first input buffer circuit, the first common end is connected with a feedback input end of the input buffer circuit of the first input buffer circuit, and the second connection end is connected with an output end of the broadband buffer analog switch circuit; the feedback switch circuit is used for providing a feedback path for the broadband buffering analog switch circuit and providing a switch control function for the broadband buffering analog switch circuit.

Further, a second input buffer circuit identical to the first input buffer circuit is also included; the input end of the input buffer circuit of the second input buffer circuit is used as the second input end of the broadband buffer analog switch circuit, the first output end of the input buffer circuit of the second input buffer circuit is respectively connected with the feedback switch circuit and the broadband switch circuit, and the feedback input end of the input buffer circuit of the second input buffer circuit is connected with the feedback switch circuit; the broadband switching circuit further comprises a second broadband switching circuit input; the input end of the second broadband switch circuit is connected with the first output end of the input buffer circuit of the second input buffer circuit; the broadband switch circuit is also used for providing a switching function for the electric signals output by the first input buffer circuit and the second input buffer circuit; the feedback switch circuit further comprises a third connecting end and a second common end; the third connecting end is connected with a first output end of the input buffer circuit of the second input buffer circuit, and the second common end is connected with a feedback input end of the input buffer circuit of the second input buffer circuit; the feedback switch circuit is also used for providing a switch switching control function for the electric signals output by the first input buffer circuit and the second input buffer circuit.

Further, the low frequency input circuit comprises a resistor R11, a resistor R12 and an operational amplifier U11; the resistor R11 is connected between the low frequency input circuit input and the positive input of the operational amplifier U11; the resistor R12 is connected between the positive input terminal of the operational amplifier U11 and ground GND; the negative input end of the operational amplifier U11 is connected with the feedback circuit connecting end, and the output end of the operational amplifier U11 is connected with the low-frequency input circuit output end;

the high-frequency input buffer circuit comprises a first transistor Q11, a first constant current source I11 and a capacitor C12; a control electrode of the first transistor Q11 is connected with the low-frequency input circuit connection end, a first electrode of the first transistor Q11 is used as an input end of an analog signal power supply Vcc, and a second electrode of the first transistor Q11 is connected with the high-frequency input buffer circuit output end; one end of the first constant current source I11 is connected with the second pole of the first transistor Q11, and the other end is used for being connected with a power supply Vee; the capacitor C12 is connected between the input end of the high-frequency input buffer circuit and the control electrode of the first transistor Q11;

the feedback circuit comprises a resistor R14 and a resistor R15; the resistor R14 is connected between the first connection end of the feedback circuit and the ground GND; the resistor R15 is connected between the first connection end of the feedback circuit and the second connection end of the feedback circuit.

Further, the low-frequency input circuit further comprises a capacitor C11 and a resistor R13; the capacitor C11 is connected between the negative input end of the operational amplifier U11 and the output end of the operational amplifier U11 and is used for compensating the amplitude-frequency response of the operational amplifier U11 and enabling the amplitude-frequency response to be flatter; a resistor R13 is connected between the output of the operational amplifier U11 and the low frequency input circuit output.

Further, the feedback switch circuit includes a first feedback switch sub-circuit and a resistor R21; the first feedback switch sub-circuit comprises a single-pole double-throw analog switch K21 and a resistor R22, and the single-pole double-throw analog switch K21 comprises a common terminal, a first terminal and a second terminal; the common terminal of the single-pole double-throw analog switch K21 is connected with the first common terminal of the feedback switch circuit; one end of the resistor R22 is connected with the first end of the single-pole double-throw analog switch K21, and the other end of the resistor R22 is connected with the first connecting end of the feedback switch circuit; the resistor R21 is connected between the second terminal of the single-pole double-throw analog switch K21 and the second connection terminal of the feedback switch circuit.

Further, the feedback switch circuit further comprises a second feedback switch sub-circuit; the second feedback switch sub-circuit is the same as the first feedback switch sub-circuit; the common end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit is connected with the second common end of the feedback switch circuit, one end of a resistor R22 of the second feedback switch sub-circuit is connected with the first end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit, the other end of the resistor R22 of the second feedback switch sub-circuit is connected with the third connecting end of the feedback switch circuit, and the second end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit is connected with the second end of the single-pole double-throw analog switch K21 of the first feedback switch sub-circuit.

Further, the broadband switching circuit includes a current source circuit and a first switching bridge circuit; the current source circuit is used for providing a current source for the first switch bridge circuit; the first switch bridge circuit comprises a first connection end of the switch bridge circuit, a second connection end of the switch bridge circuit, a first connection end of a current source and a second connection end of the current source; the first current source connecting end and the second current source connecting end are respectively connected with the current source circuit, and the first switch bridge circuit connecting end and the second switch bridge circuit connecting end are respectively connected with the first broadband switch circuit input end and the broadband switch circuit output end;

the first switch bridge circuit comprises a single-pole double-throw analog switch K31, a single-pole double-throw analog switch K32 and a first diode bridge circuit; the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 respectively comprise a common terminal, a first terminal and a second terminal; the first diode bridge circuit comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end, the first connecting end and the second connecting end of the first diode bridge circuit are respectively connected with the common ends of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32, and the third connecting end and the fourth connecting end of the first diode bridge circuit are respectively connected with the first connecting end of the switch bridge circuit and the second connecting end of the switch bridge circuit; the first end and the second end of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 are respectively connected and are respectively connected with the first current source connecting end and the second current source connecting end;

the current source circuit comprises a second constant current source I31 and a third constant current source I32; one end of the second constant current source I31 is used for being connected with a power ground GND, and the other end of the second constant current source I31 is connected with the first connection end of the current source; one end of the third constant current source I32 is used for being connected with a power ground GND, and the other end of the third constant current source I32 is connected with the second current source connecting end;

the first diode bridge circuit comprises a resistor R31, a resistor R32, a diode D31, a diode D32, a diode D33 and a diode D34; one end of the resistor R31 is connected to the anodes of the diodes D31 and D33, the other end of the resistor R32 is connected to the first connection end of the first diode bridge circuit, one end of the resistor R32 is connected to the cathodes of the diodes D32 and D34, the other end of the resistor R32 is connected to the second connection end of the first diode bridge circuit, the cathode of the diode D31 and the anode of the diode D32 are connected to the third connection end of the first diode bridge circuit, and the cathode of the diode D33 and the anode of the diode D34 are connected to the fourth connection end of the first diode bridge circuit.

Further, the first switch bridge circuit further comprises a second diode bridge circuit; the second diode bridge circuit is the same as the first diode bridge circuit; the first connecting end of the second diode bridge circuit is connected with the second connecting end of the first diode bridge circuit, the second connecting end of the second diode bridge circuit is connected with the first connecting end of the first diode bridge circuit, the third connecting end of the second diode bridge circuit is connected with the input end of the second broadband switch circuit, and the fourth connecting end of the second diode bridge circuit is connected with the third connecting end of the first diode bridge circuit.

Further, the broadband switch circuit further comprises an output circuit connected between the second connection end of the switch bridge circuit and the output end of the broadband switch circuit; the output circuit comprises a second transistor Q31 and a fourth current source I33; a control electrode of the second transistor Q31 is connected with the second connection end of the switch bridge circuit, a first electrode of the second transistor Q31 is used as an input end of an analog signal power supply Vcc, and a second electrode of the second transistor Q31 is connected with the output end of the broadband switch circuit; one end of the fourth current source I33 is connected to the second pole of the second transistor Q31, and the other end is used for being connected to a power supply Vee;

and/or the first diode bridge circuit comprises a PIN diode.

According to a second aspect, an embodiment provides a wideband buffered analog switch integrated circuit, including the wideband buffered analog switch circuit of the first aspect; the broadband buffering analog switch circuit comprises n first input buffering circuits, wherein the input end of each input buffering circuit is used as one input end of the broadband buffering analog switch circuit, and n is an integer greater than 1; the broadband switch circuit comprises n first broadband switch circuit input ends and is respectively connected with n first output ends of the input buffer circuits; the broadband switch circuit is also used for providing a switching function for the electric signals output by the n first input buffer circuits; the broadband switch circuit comprises a current source circuit and n first switch bridge circuits; the current source circuit is used for providing current sources for the n first switch bridge circuits; the first switch bridge circuit comprises a first connection end of the switch bridge circuit, a second connection end of the switch bridge circuit, a first connection end of a current source and a second connection end of the current source; the first current source connecting end and the second current source connecting end are respectively connected with the current source circuits, the first rectifying bridge circuit connecting end of each first rectifying bridge circuit is linked with the input end of one first broadband switch circuit, and the second switch bridge circuit connecting end is connected with the output end of the broadband switch circuit; the first switch bridge circuit comprises a single-pole double-throw analog switch K31, a single-pole double-throw analog switch K32 and a first diode bridge circuit; the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 respectively comprise a common terminal, a first terminal and a second terminal; the first diode bridge circuit comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end, the first connecting end and the second connecting end of the first diode bridge circuit are respectively connected with the common ends of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32, and the third connecting end and the fourth connecting end of the first diode bridge circuit are respectively connected with the first connecting end of the switch bridge circuit and the second connecting end of the switch bridge circuit; the first connecting end of the single-pole double-throw analog switch K31 is connected with the first end of the single-pole double-throw analog switch K32 and is connected with the first connecting end of the current source; the second connection end of the single-pole double-throw analog switch K31 is connected with the second end of the single-pole double-throw analog switch K32 and is connected with the second connection end of the current source; the current source circuit comprises a second constant current source I31 and a third constant current source I32; one end of the second constant current source I31 is used for being connected with a power ground GND, and the other end of the second constant current source I31 is connected with the first connection end of the current source; one end of the third constant current source I32 is used for being connected with a power ground GND, and the other end of the third constant current source I32 is connected with the second current source connecting end; the first diode bridge circuit comprises a resistor R31, a resistor R32, a diode D31, a diode D32, a diode D33 and a diode D34; one end of the resistor R31 is connected with the anodes of the diode D31 and the diode D33, the other end of the resistor R32 is connected with the first connection end of the first diode bridge circuit, one end of the resistor R32 is connected with the cathodes of the diode D32 and the diode D34, the other end of the resistor R32 is connected with the second connection end of the first diode bridge circuit, the cathode of the diode D31 and the anode of the diode D32 are connected with the third connection end of the first diode bridge circuit, and the cathode of the diode D33 and the anode of the diode D34 are connected with the fourth connection end of the first diode bridge circuit; the feedback switch circuit comprises n first connecting ends and is respectively connected with the first output ends of the n input buffer circuits; the input buffer circuit also comprises n first common ends which are respectively connected with the feedback input ends of the input buffer circuit; the feedback switch circuit is also used for providing a switch switching control function for the n electric signals output by the first input buffer circuits.

The broadband buffered analog switch circuit and the broadband buffered analog switch integrated circuit according to the above embodiments include a first input buffer circuit, a feedback switch circuit, and a broadband switch circuit. The first input buffer circuit comprises a low-frequency input circuit, a high-frequency input buffer circuit and a feedback circuit, wherein high-frequency signals, direct currents and/or low-frequency signals input into the broadband buffering analog switch circuit are buffered through the high-frequency input buffer circuit and then are respectively output to the feedback switch circuit and the broadband switch circuit, and then the broadband switch circuit and the feedback switch circuit respectively provide the broadband buffering analog switch circuit with the switching function of the input signals. Because the feedback circuit provides loop negative feedback for the low-frequency input circuit, the high-frequency input buffer circuit and the broadband switch circuit, the static working voltage of the broadband buffer analog switch circuit is more stable, and the broadband buffer analog switch circuit has excellent switching performance under direct current, low frequency and high frequency.

Drawings

FIG. 1 is a schematic diagram of an exemplary embodiment of a wideband buffered analog switch circuit;

FIG. 2 is a schematic circuit diagram of a first input buffer circuit according to an embodiment;

FIG. 3 is a schematic circuit diagram of an embodiment of a feedback switch circuit;

FIG. 4 is a schematic circuit diagram of an embodiment of a broadband switching circuit;

FIG. 5 is a schematic diagram of a wideband buffered analog switch circuit according to another embodiment;

FIG. 6 is a schematic circuit diagram of a feedback switch circuit according to another embodiment;

FIG. 7 is a schematic circuit connection diagram of another embodiment of a broadband switching circuit;

FIG. 8 is a schematic diagram of an alternative embodiment of a wideband snubber analog switch circuit;

FIG. 9 is a schematic circuit diagram of a wideband switching circuit according to another embodiment;

fig. 10 is a circuit connection diagram of a feedback switch circuit in another embodiment.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

Some terms referred to in the present application will be described first.

The transistors in the present application may be transistors of any structure, such as Bipolar Junction Transistors (BJTs) or Field Effect Transistors (FETs). When the transistor is a bipolar transistor, the control electrode of the transistor refers to the grid electrode of the bipolar transistor, the first electrode can be the collector or the emitter of the bipolar transistor, the corresponding second electrode can be the emitter or the collector of the bipolar transistor, and in the practical application process, the emitter and the collector can be interchanged according to the signal flow direction; when the transistor is a field effect transistor, the control electrode refers to a gate electrode of the field effect transistor, the first electrode may be a drain electrode or a source electrode of the field effect transistor, and the corresponding second electrode may be a source electrode or a drain electrode of the field effect transistor, and in an actual application process, "source electrode" and "drain electrode" may be interchanged according to a signal flow direction. The transistor in the display device is typically a Thin Film Transistor (TFT), and in this case, the control electrode of the transistor refers to the source electrode of the thin film transistor. The Light Emitting element may be an Organic Light-Emitting Diode (OLED), an electrodeless Light-Emitting Diode (electrodeless led), a quantum dot Light-Emitting Diode (qd), or the like, and in other embodiments, may also be other Light-Emitting elementsAnd (3) a component. The first end of the light emitting element may be a cathode or an anode, and correspondingly, the second end of the light emitting element is an anode or a cathode. Those skilled in the art will understand that: current should flow from the anode to the cathode of the light emitting element, and thus, the anode and the cathode of the light emitting element can be determined based on the flow direction of current. The active level can be a high level or a low level, and can be adaptively replaced according to the function implementation of a specific component. The first potential terminal, the second potential terminal and the third potential terminal are power supplies for the driving circuit to work. In one embodiment, the first potential terminal may be a low potential terminal V_SSOr ground, the second potential terminal may be a low potential terminal V_SSLOr ground, the third potential terminal may be a high potential terminal V_HIn other embodiments, the substitution may be made adaptively. It should be noted that: for the pixel circuit, the first potential terminal (e.g., the low-level terminal V)_SSOr ground) and a third potential terminal (e.g., high-level terminal V)_H) The first potential terminal and the second potential terminal are specifically introduced for better understanding of the technical solution of the present application, and are not a part of the pixel circuit of the present application.

In the embodiment of the invention, a broadband buffer analog switch circuit and a broadband buffer analog switch integrated circuit are disclosed, and the broadband buffer analog switch circuit comprises a first input buffer circuit, a feedback switch circuit and a broadband switch circuit. The first input buffer circuit comprises a low-frequency input circuit, a high-frequency input buffer circuit and a feedback circuit, wherein high-frequency signals, direct currents and/or low-frequency signals input into the broadband buffering analog switch circuit are buffered through the high-frequency input buffer circuit and then are respectively output to the feedback switch circuit and the broadband switch circuit, and then the broadband switch circuit and the feedback switch circuit respectively provide the broadband buffering analog switch circuit with the switching function of the input signals. Because the feedback circuit provides loop negative feedback for the low-frequency input circuit, the high-frequency input buffer circuit and the broadband switch circuit, the broadband buffer analog switch circuit has a stable static working state, and further the broadband buffer analog switch circuit has excellent switching performance under direct current, low frequency and high frequency.

Example one

Referring to fig. 1, a schematic diagram of a wideband buffer analog switch circuit according to an embodiment includes a first input buffer circuit 10, a feedback switch circuit 20, and a wideband switch circuit 30. The first input buffer circuit 10 includes an input buffer circuit input, an input buffer circuit first output, and an input buffer circuit feedback input. The input end of the input buffer circuit is used as the first input end of the broadband buffer analog switch circuit, the first output end of the input buffer circuit is respectively connected with the feedback switch circuit 20 and the broadband switch circuit 30, and the feedback input end of the input buffer circuit is connected with the feedback switch circuit 20.

The first input buffer circuit 10 includes a low frequency input circuit 11, a high frequency input buffer circuit 12, and a feedback circuit 13. The low frequency input circuit 11 includes a low frequency input circuit input terminal, a feedback circuit connection terminal, and a low frequency input circuit output terminal, wherein the low frequency input circuit input terminal is connected to the input buffer circuit input terminal of the first input buffer circuit, the feedback circuit connection terminal is connected to the feedback circuit 13, and the low frequency input circuit output terminal is connected to the high frequency input buffer circuit 12. The low-frequency input circuit 11 is configured to buffer and amplify a direct current and/or a low-frequency signal input by a first input terminal of the wideband buffer analog switch circuit, and output the amplified direct current and/or low-frequency signal to the high-frequency input buffer circuit 12.

The high frequency input buffer circuit 12 includes a high frequency input buffer circuit input terminal, a low frequency input circuit connection terminal, and a high frequency input buffer circuit output terminal. Wherein, the input end of the high frequency input buffer circuit is connected to the input end of the input buffer circuit of the first input buffer circuit 10, the low frequency input circuit connection end is connected to the low frequency input circuit 11, and the output end of the high frequency input buffer circuit is connected to the first output end of the input buffer circuit of the first input buffer circuit 10, as shown in fig. 1, a node J11 is a connection node of the first output end of the input buffer circuit of the first input buffer circuit 10. The high frequency input buffer circuit 12 is configured to buffer a high frequency signal input from a first input terminal of the wideband buffer analog switch circuit and a dc and/or low frequency signal output from a low frequency circuit output terminal of the low frequency input circuit 11, and then output the signals to the feedback switch circuit 20 and the wideband switch circuit 30, respectively.

The feedback circuit 13 includes a first connection terminal and a second connection terminal. Wherein, the first connection end of the feedback circuit is connected to the feedback circuit connection end of the low frequency input circuit 11, and the second connection end of the feedback circuit is connected to the feedback input end of the input buffer circuit of the first input buffer circuit, as shown in fig. 1, a node J12 is a connection node of the feedback input end of the input buffer circuit of the first input buffer circuit 10. The feedback circuit 13 is used to provide loop negative feedback for the low frequency input circuit 11, the high frequency input buffer circuit 12 and the wideband switching circuit 30 to stabilize the static operating voltage of the wideband buffered analog switching circuit.

The wideband switching circuit 30 includes a first wideband switching circuit input and a wideband switching circuit output. The input end of the first broadband switch circuit is connected to the first output end of the input buffer circuit of the first input buffer circuit 10, and the output end of the broadband switch circuit is used as the output end of the broadband buffer analog switch circuit. The broadband switching circuit 30 is configured to provide a switching function for electrical signals transmitted between the first input terminal of the broadband buffered analog switching circuit and the output terminal of the broadband switching circuit.

The feedback switch circuit 20 includes a first connection terminal, a second connection terminal, and a first common terminal. The first connection end is connected with the first output end of the input buffer circuit of the first input buffer circuit 10, the first common end is connected with the feedback input end of the input buffer circuit of the first input buffer circuit 10, and the second connection end is connected with the output end of the broadband buffer analog switch circuit. The feedback switch circuit 20 is configured to provide a switching control function for an electrical signal transmitted between the first input terminal of the wideband buffered analog switch circuit and the output terminal of the switch circuit.

Referring to fig. 2, a circuit connection diagram of the first input buffer circuit according to an embodiment is shown, in which the low frequency input circuit 11 includes a resistor R11, a resistor R12, and an operational amplifier U11, the resistor R11 is connected between the input terminal of the low frequency input circuit and the positive input terminal of the operational amplifier U11, the resistor R12 is connected between the positive input terminal of the operational amplifier U11 and the ground GND, the negative input terminal of the operational amplifier U11 is connected to the feedback circuit connection terminal, and the output terminal of the operational amplifier U11 is connected to the output terminal of the low frequency input circuit. In one embodiment, the low frequency input circuit 11 further includes a capacitor C11 and a resistor R13, the capacitor C11 is connected between the negative input terminal of the operational amplifier U11 and the output terminal of the operational amplifier U11 for compensating the amplitude-frequency response of the operational amplifier U11 to make the amplitude-frequency response flatter, and the resistor R13 is connected between the output terminal of the operational amplifier U11 and the output terminal of the low frequency input circuit. The resistor R11 and the resistor R12 attenuate an input signal, the operational amplifier U11 amplifies the attenuated signal, and the amplified signal is connected to the high-frequency input buffer circuit via the resistor R13.

The high frequency input buffer circuit 12 includes a first transistor Q11, a first constant current source I11, and a capacitor C12, a control electrode of the first transistor Q11 is connected to the low frequency input circuit connection terminal, a first electrode of the first transistor Q11 is used as an input terminal of the analog signal power supply Vcc, and a second electrode of the first transistor Q11 is connected to the high frequency input buffer circuit output terminal. The first constant current source I11 has one end connected to the second pole of the first transistor Q11 and the other end connected to the power source Vee. The capacitor C12 is connected between the input of the high frequency input buffer circuit and the control electrode of the first transistor Q11. The high-frequency input buffer circuit 12 buffers the input high-frequency signal and the dc and low-frequency signals output from the low-frequency input circuit 11 and outputs the signals to the wide-band switch circuit 30, and has a high input impedance, satisfying a high input impedance characteristic. The buffering function of the high-frequency input buffer circuit 12 is realized by an emitter follower formed of the first transistor Q11 and the first constant current source I11, which has characteristics of high input impedance and low output impedance. In one embodiment, the first transistor Q11 is a radio frequency triode for high bandwidth performance, and the ac coupling capacitor C12 provides dc and low frequency isolation between the signal input and the emitter follower input.

The feedback circuit 13 comprises a resistor R14 and a resistor R15, the resistor R14 is connected between the first connection terminal of the feedback circuit and the ground GND, and the resistor R15 is connected between the first connection terminal of the feedback circuit and the second connection terminal of the feedback circuit.

Referring to fig. 3, a circuit connection diagram of a feedback switch circuit according to an embodiment is a connection diagram of a feedback switch circuit 20 of a wideband buffer analog switch circuit including a first input buffer circuit 10, where the feedback switch circuit 20 includes a first feedback switch sub-circuit and a resistor R21. The first feedback switch sub-circuit comprises a single-pole double-throw analog switch K21 and a resistor R22, the single-pole double-throw analog switch K21 comprises a common end, a first end and a second end, the common end of the single-pole double-throw analog switch K21 is connected with the first common end of the feedback switch circuit 20, one end of the resistor R22 is connected with the first end of the single-pole double-throw analog switch K21, and the other end of the resistor R22 is connected with the first connecting end of the feedback switch circuit 20. The resistor R21 is connected between the second terminal of the single-pole double-throw analog switch K21 and the second connection terminal of the feedback switch circuit, and as shown in fig. 3, the node J13 is a connection node of the second connection terminal of the feedback switch circuit 20.

Referring to fig. 4, which is a circuit connection diagram of a wideband switching circuit according to an embodiment, the wideband switching circuit 30 includes a current source circuit 31 and a first switch bridge circuit 32. The current source circuit 31 is used to provide a current source for the first switching bridge circuit 32. The first switch bridge circuit 32 includes a first connection end of the switch bridge circuit, a second connection end of the switch bridge circuit, a first connection end of the current source, and a second connection end of the current source. The first connection end and the second connection end of the current source are respectively connected with the current source circuit 31, and the first connection end and the second connection end of the switch bridge circuit are respectively connected with the input end of the first broadband switch circuit and the output end of the broadband switch circuit. The first switch bridge circuit 32 includes a single-pole double-throw analog switch K31, a single-pole double-throw analog switch K32, and a first diode bridge circuit 321. The single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 respectively comprise a common end, a first end and a second end, the first diode bridge circuit 321 comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end, the first connecting end and the second connecting end of the first diode bridge circuit 321 are respectively connected with the common end of the single-pole double-throw analog switch K31 and the common end of the single-pole double-throw analog switch K32, the third connecting end and the fourth connecting end of the first diode bridge circuit 321 are respectively connected with the first connecting end and the second connecting end of the switch bridge circuit, and the first end and the second end of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 are respectively connected with the first connecting end and the second connecting end of the current source. The current source circuit 31 comprises a second constant current source I31 and a third constant current source I32, wherein one end of the second constant current source I31 is connected with the power ground GND, the other end of the second constant current source I31 is connected with the first connection end of the current source, one end of the third constant current source I32 is connected with the power ground GND, and the other end of the third constant current source I32 is connected with the second connection end of the current source. The broadband switching circuit 30 provides an ultra-wideband signal switching function for the output signal of the high-frequency buffer circuit of the first input buffer circuit.

The first diode bridge circuit 321 includes a resistor R31, a resistor R32, a diode D31, a diode D32, a diode D33, and a diode D34; one end of the resistor R31 is connected to the anodes of the diodes D31 and D33, the other end of the resistor R31 is connected to the first connection end of the first diode bridge 321, one end of the resistor R32 is connected to the cathodes of the diodes D32 and D34, the other end of the resistor R32 is connected to the second connection end of the first diode bridge 321, the cathode of the diode D31 and the anode of the diode D32 are connected to the third connection end of the first diode bridge 321, and the cathode of the diode D33 and the anode of the diode D34 are connected to the fourth connection end of the first diode bridge 321. The first diode bridge circuit 321 is used to provide a signal path for the high frequency input buffer circuit of the first input buffer circuit.

In one embodiment, the broadband switching circuit 30 further comprises an output circuit 33 coupled between the second terminal of the switch bridge circuit and the output of the broadband switching circuit. The output circuit 33 comprises a second transistor Q31 and a fourth current source I33, a control electrode of the second transistor Q31 is connected with the second connection terminal of the rectifier bridge circuit, a first electrode of the second transistor Q31 is used as an input terminal of an analog signal power supply Vcc, and a second electrode of the second transistor Q31 is connected with the output terminal of the broadband switch circuit. A fourth current source I33 has one terminal connected to the second pole of the second transistor Q31 and another terminal for connection to a power supply Vee. In one embodiment, first diode bridge circuit 321 comprises a PIN diode. The dc current-voltage characteristic of the PIN diode is the same as that of the PN junction diode, but there is a fundamental difference in the microwave band because the total charge of the I layer of the PIN diode is mainly generated by the bias current. Rather than microwave current transients, it presents only a linear resistance to microwave signals, and thus, a PIN diode can be used as a variable impedance element, which is often used in circuits such as high frequency switching, phase shifting, modulation, clipping, etc.

In an embodiment of the application, a broadband buffer analog switch circuit is disclosed, which comprises a first input buffer circuit, a feedback switch circuit and a broadband switch circuit. The first input buffer circuit comprises a low-frequency input circuit, a high-frequency input buffer circuit and a feedback circuit, wherein a high-frequency signal input into the broadband buffering analog switch circuit and a direct current or low-frequency signal output by the low-frequency input circuit are buffered by the high-frequency input buffer circuit and then are respectively output to the feedback switch circuit and the broadband switch circuit, and then the broadband switch circuit and the feedback switch circuit respectively provide the broadband buffering analog switch circuit with the switching function of an electric signal. Because the feedback circuit provides loop negative feedback for the low-frequency input circuit, the high-frequency input buffer circuit and the broadband switch circuit, the static working voltage of the broadband buffer analog switch circuit is more stable, and the broadband buffer analog switch circuit has excellent switching performance under direct current, low frequency and high frequency.

Example two

Referring to fig. 5, a schematic diagram of another embodiment of a connection of a wideband buffer analog switch circuit is shown, based on the improvement of the wideband buffer analog switch circuit in the first embodiment, the wideband buffer analog switch circuit further includes a second input buffer circuit 40 that is the same as the first input buffer circuit 10. An input buffer circuit input end of the second input buffer circuit 40 is used as a second input end of the broadband buffer analog switch circuit, a first output end of the input buffer circuit of the second input buffer circuit 40 is respectively connected with the feedback switch circuit 20 and the broadband switch circuit 30, and a feedback input end of the input buffer circuit of the second input buffer circuit 40 is connected with the feedback switch circuit 20. As shown in fig. 5, a node J21 is a connection node of the first output terminal of the input buffer circuit of the second input buffer circuit 40, and a node J22 is a connection node of the feedback input terminal of the input buffer circuit of the second input buffer circuit 40. The broadband switch circuit 30 further comprises a second broadband switch circuit input end, wherein the second broadband switch circuit input end is connected with the first output end of the input buffer circuit of the second input buffer circuit 40, and the broadband switch circuit is further configured to provide a switching function for the electrical signals output by the first input buffer circuit 10 and the second input buffer circuit 40. The feedback switch circuit 20 further includes a third connection terminal connected to the first output terminal of the input buffer circuit of the second input buffer circuit 40, and a second common terminal connected to the feedback input terminal of the input buffer circuit of the second input buffer circuit 40. The feedback switch circuit 20 is also used to provide a switching control function for the electrical signals output by the first input buffer circuit 10 and the second input buffer circuit 40.

Referring to fig. 6, a schematic circuit connection diagram of a feedback switch circuit according to another embodiment is a schematic connection diagram of a feedback switch circuit 20 in which a wideband buffer analog switch circuit includes a first input buffer circuit 10 and a second input buffer circuit 40, where the feedback switch circuit 20 further includes a second feedback switch sub-circuit, and the second feedback switch sub-circuit is the same as the first feedback switch sub-circuit. The common end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit is connected with the second common end of the feedback switch circuit, one end of a resistor R22 of the second feedback switch sub-circuit is connected with the first end of the single-pole double-throw analog switch K21, the other end of the resistor R22 of the second feedback switch sub-circuit is connected with the third connecting end of the feedback switch circuit 20, and the second end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit is connected with the second end of the single-pole double-throw analog switch K21 of the first feedback switch sub-circuit.

Referring to fig. 7, which is a circuit connection diagram of another embodiment of the wideband switch circuit, the first switch bridge circuit 32 further includes a second diode bridge circuit 322. The second diode bridge circuit 322 is the same as the first diode bridge circuit 321. The first connection end of the second diode bridge circuit 322 is connected with the second connection end of the first diode bridge circuit 321, the second connection end of the second diode bridge circuit 322 is connected with the first connection end of the first diode bridge circuit 321, the third connection end of the second diode bridge circuit 322 is connected with the input end of the second broadband switch circuit, and the fourth connection end of the second diode bridge circuit 322 is connected with the third connection end of the first diode bridge circuit 321. Second diode bridge circuit 322 is used to provide a signal path for the high frequency input buffer circuit of the second input buffer circuit. The broadband switch circuit 30 provides an ultra-wideband signal switching function for output signals of the high-frequency buffer circuits of the first input buffer circuit and the second input buffer circuit.

In this embodiment, the resistor R21, the resistor 22, the resistor R31, and the resistor R32 in the feedback switch circuit and the broadband switch circuit are high-frequency blocking resistors, so as to prevent high-frequency signals from leaking into the single-pole double-throw analog switch K21, the single-pole double-throw analog switch K31, and the single-pole double-throw analog switch K32. The second constant current source I31 and the third constant current source I32 in the broadband switch circuit provide constant current sources for the first diode bridge circuit 321 and the second diode bridge circuit 322, and the second constant current source I31 and the third constant current source I32 are two constant current sources with opposite current values, for example, the second constant current source I31 is 1mA, and the third constant current source I32 is-1 mA. The single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 are used for selecting a signal path, for example, the second constant current source I31 is 1mA, the third constant current source I32 is-1 mA, the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 gate the second constant current source I31 and the third constant current source I32 respectively, namely, the first diode bridge circuit 321 gates, and the second diode bridge circuit 322 is closed, so that the signal input by the first input buffer circuit is output from the output end of the broadband buffer analog switch circuit, and the signal input by the second input buffer circuit is turned off. Otherwise, the signal input by the second input buffer circuit is output, and the signal input by the first input buffer circuit is switched off, so that the one-out-of-two function of the broadband buffer analog switch circuit is realized. The second transistor Q31 and the fourth current source I33 of the output circuit form an emitter follower, buffer and output the output signal of the broadband buffer analog switch circuit, and have characteristics of high input impedance and low output impedance. In one embodiment, the second transistor Q31 is an emitter follower transistor with high driving capability to improve the bandwidth and high driving capability. In one embodiment, the resistor R14 of the feedback circuit 13 is an adjustable resistor to provide loop negative feedback for the low frequency input circuit, the high frequency input buffer circuit and the wideband switching circuit, so as to stabilize the static operating voltage of the wideband buffered analog switching circuit. The resistor R14 and the resistor R15 with adjustable resistance values, the resistor R11 and the resistor R12 of the low-frequency input circuit and the middle resistor R21 of the switch module jointly determine the amplification factor of the direct current and the low frequency of the broadband buffering analog switch circuit, and the amplification factor is [ R12 (R14+ R15+ R21) ]/[ R14 (R12+ R11) ]. The amplification factor of the very low frequency can be adjusted by adjusting the resistance adjustable resistor R14, and the amplification factor is consistent with the amplification factor of the high frequency. The feedback switch module comprises a resistor R21 and two resistors R22, and two single-pole double-throw analog switches K21, which are used for selecting a signal path for inputting a broadband buffer analog switch circuit signal, when the resistor R22 of the second feedback switch sub-circuit is switched on and the resistor R22 of the first feedback switch sub-circuit is switched off, the output of the output circuit 33 is connected to the feedback circuit of the first input buffer circuit, meanwhile, the signal input by the first input buffer circuit is switched on, and the signal input by the second input buffer circuit is switched to internal feedback, so as to stabilize the working states of the high-frequency input buffer circuit and the low-frequency input circuit in the second input buffer circuit. Otherwise, the signal input by the first input buffer circuit is closed. While the broadband switching circuit and the switching circuit work in cooperation, for example, when the first input buffer circuit is gated, the broadband switching circuit needs to gate the high-frequency input buffer circuit and the output circuit at the same time.

In the embodiment of the application, the input buffer and the output buffer of the broadband buffer analog switch circuit use broadband emitter follower, the large loop negative feedback of the low-frequency operational amplifier is used for stabilizing the static working voltage of the input buffer and the output buffer, the PIN diode bridge circuit is adopted for providing a broadband signal switching function, and the influence of difference between PIN diodes on the switching performance can be effectively reduced by driving the PIN diode bridge through the constant current source. Because the large loop negative feedback of the low-frequency operational amplifier is used for stabilizing the direct current and low-frequency characteristics of the broadband buffer analog switch, the influence of the poor direct current and low-frequency characteristics of the PIN diode bridge circuit on the switching performance is avoided.

EXAMPLE III

The application also discloses a broadband buffer analog switch integrated circuit, which comprises the broadband buffer analog switch circuit in the first embodiment. Referring to fig. 8, it is another embodiment of a wideband buffer analog switch circuit, where the wideband buffer analog switch circuit is used to implement a multiple-select-one enable switch function, where the wideband buffer analog switch circuit includes n first input buffer circuits 10, an input end of each first input buffer circuit is used as an input end of the wideband buffer analog switch circuit, and n is an integer greater than 1. The wideband switching circuit 30 includes n first wideband switching circuit input terminals, and is connected to the input buffer circuit first output terminals of the n first input buffer circuits 10, respectively. The broadband switch circuit 30 is used to provide a switching function for the electrical signals output by the n first input buffer circuits 10. As shown in fig. 8, the nodes J11, J21 … …, and Jn1 are connection nodes of the first output terminals of the input buffer circuits of the n first input buffer circuits 10, the nodes J12, J22 … …, and Jn2 are connection nodes of the feedback input terminals of the input buffer circuits of the n first input buffer circuits 10, and the node J13 is a connection node of the second connection terminal of the feedback switch circuit 20.

Referring to fig. 9, a circuit connection diagram of a wideband switching circuit in another embodiment is shown, in which the wideband switching circuit 30 includes a current source circuit 31 and n first switching bridge circuits 32, and the current source circuit 31 is used for providing a current source for the n first switching bridge circuits 32. The first switch bridge circuit 32 includes a first connection end of the switch bridge circuit, a second connection end of the switch bridge circuit, a first connection end of the current source, and a second connection end of the current source. The first connection end and the second connection end of the current source are respectively connected with the current source circuit 31, the first connection end of the switch bridge circuit of each first switch bridge circuit is linked with the input end of one first broadband switch circuit, and the second connection end of the switch bridge circuit is connected with the output end of the broadband switch circuit. The first switch bridge circuit 32 includes a single pole double throw analog switch K31, a single pole double throw analog switch K32, and a first diode bridge circuit. The single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 respectively comprise a common terminal, a first terminal and a second terminal. The first diode bridge circuit comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end, the first connecting end and the second connecting end of the first diode bridge circuit are respectively connected with the common ends of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32, and the third connecting end and the fourth connecting end of the first diode bridge circuit are respectively connected with the first connecting end of the switch bridge circuit and the second connecting end of the switch bridge circuit. The first ends of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 are connected and connected with a first connecting end of a current source, and the second ends of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 are connected and connected with a second connecting end of the current source.

The current source circuit 31 includes a second constant current source I31 and a third constant current source I32, and the second constant current source I31 has one end for connection to the power ground GND and the other end connected to the current source first connection terminal. One end of the third constant current source I32 is used for being connected with the power ground GND, and the other end is connected with the current source second connection end. The first diode bridge circuit includes a resistor R31, a resistor R32, a diode D31, a diode D32, a diode D33, and a diode D34. One end of the resistor R31 is connected to the anodes of the diode D31 and the diode D33, the other end of the resistor R31 is connected to the first connection end of the first diode bridge circuit, one end of the resistor R32 is connected to the cathodes of the diode D32 and the diode D34, the other end of the resistor R32 is connected to the second connection end of the first diode bridge circuit, the cathode of the diode D31 and the anode of the diode D32 are connected to the third connection end of the first diode bridge circuit, and the cathode of the diode D33 and the anode of the diode D34 are connected to the fourth connection end of the first diode bridge circuit.

Referring to fig. 10, a circuit connection diagram of a feedback switch circuit in another embodiment is shown, where the feedback switch circuit includes n first connection terminals, a second connection terminal, and n first common terminals. The second connecting end is connected with the output end of the broadband buffering analog switch circuit, and the feedback switch circuit is used for providing a feedback path for the broadband buffering analog switch circuit and providing a switch control function for the broadband buffering analog switch circuit. The feedback switch circuit comprises n first feedback switch sub-circuits and a resistor R21. Each first feedback switch sub-circuit comprises a single-pole double-throw analog switch K21 and a resistor R22, the single-pole double-throw analog switch K21 comprises a common end, a first end and a second end, the common end of the single-pole double-throw analog switch K21 is connected with the first common end of the feedback switch circuit, one end of the resistor R22 is connected with the first end of the single-pole double-throw analog switch K21, and the other end of the resistor R22 is connected with the first connecting end of the feedback switch circuit. The resistor R21 is connected between the second terminal of the single-pole double-throw analog switch K21 and the second connection terminal of the feedback switch circuit. The feedback switch circuit comprises n first connecting ends which are respectively connected with the first output ends of the n input buffer circuits, n first public ends which are respectively connected with the feedback input ends of the n input buffer circuits, and the feedback switch circuit is also used for providing a switch switching control function for the electric signals output by the n first input buffer circuits.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.

Claims

1. A broadband buffer analog switch circuit is characterized by comprising a first input buffer circuit, a feedback switch circuit and a broadband switch circuit; the first input buffer circuit comprises an input end of the input buffer circuit, a first output end of the input buffer circuit and a feedback input end of the input buffer circuit; the input end of the input buffer circuit is used as a first input end of the broadband buffer analog switch circuit, the first output end of the input buffer circuit is respectively connected with the feedback switch circuit and the broadband switch circuit, and the feedback input end of the input buffer circuit is connected with the feedback switch circuit;

the first input buffer circuit comprises a low-frequency input circuit, a high-frequency input buffer circuit and a feedback circuit;

the low-frequency input circuit comprises a low-frequency input circuit input end, a feedback circuit connecting end and a low-frequency input circuit output end; the input end of the low-frequency input circuit is connected with the input end of the input buffer circuit of the first input buffer circuit, the connecting end of the feedback circuit is connected with the feedback circuit, and the output end of the low-frequency input circuit is connected with the high-frequency input buffer circuit; the low-frequency input circuit is used for buffering and amplifying direct current and/or low-frequency signals input by a first input end of the broadband buffering analog switch circuit and then outputting the signals to the high-frequency input buffer circuit;

the high-frequency input buffer circuit comprises a high-frequency input buffer circuit input end, a low-frequency input circuit connecting end and a high-frequency input buffer circuit output end; the input end of the high-frequency input buffer circuit is connected with the input end of the input buffer circuit of the first input buffer circuit, the connecting end of the low-frequency input circuit is connected with the low-frequency input circuit, and the output end of the high-frequency input buffer circuit is connected with the first output end of the input buffer circuit of the first input buffer circuit; the high-frequency input buffer circuit is used for buffering a high-frequency signal input by a first input end of the broadband buffer analog switch circuit and a direct current and/or low-frequency signal output by a low-frequency circuit output end of the low-frequency input circuit and then respectively outputting the high-frequency signal and the direct current and/or low-frequency signal to the feedback switch circuit and the broadband switch circuit;

the feedback circuit comprises a first connection end of the feedback circuit and a second connection end of the feedback circuit; the first connecting end of the feedback circuit is connected with the connecting end of the feedback circuit of the low-frequency input circuit, and the second connecting end of the feedback circuit is connected with the feedback input end of the input buffer circuit of the first input buffer circuit; the feedback circuit is used for providing loop negative feedback for the low-frequency input circuit, the high-frequency input buffer circuit and the broadband switch circuit so as to stabilize the static working voltage of the broadband buffer analog switch circuit;

2. The wideband buffered analog switch circuit as defined in claim 1, further comprising a second input buffer circuit identical to the first input buffer circuit;

the input end of the input buffer circuit of the second input buffer circuit is used as the second input end of the broadband buffer analog switch circuit, the first output end of the input buffer circuit of the second input buffer circuit is respectively connected with the feedback switch circuit and the broadband switch circuit, and the feedback input end of the input buffer circuit of the second input buffer circuit is connected with the feedback switch circuit;

the broadband switching circuit further comprises a second broadband switching circuit input; the input end of the second broadband switch circuit is connected with the first output end of the input buffer circuit of the second input buffer circuit; the broadband switch circuit is also used for providing a switching function for the electric signals output by the first input buffer circuit and the second input buffer circuit;

the feedback switch circuit further comprises a third connecting end and a second common end; the third connecting end is connected with a first output end of the input buffer circuit of the second input buffer circuit, and the second common end is connected with a feedback input end of the input buffer circuit of the second input buffer circuit; the feedback switch circuit is also used for providing a switch switching control function for the electric signals output by the first input buffer circuit and the second input buffer circuit.

3. The wideband buffered analog switch circuit as claimed in claim 2, wherein the low frequency input circuit includes a resistor R11, a resistor R12, and an operational amplifier U11; the resistor R11 is connected between the low frequency input circuit input and the positive input of the operational amplifier U11; the resistor R12 is connected between the positive input terminal of the operational amplifier U11 and ground GND; the negative input end of the operational amplifier U11 is connected with the feedback circuit connecting end, and the output end of the operational amplifier U11 is connected with the low-frequency input circuit output end;

and/or, the high-frequency input buffer circuit comprises a first transistor Q11, a first constant current source I11 and a capacitor C12; a control electrode of the first transistor Q11 is connected with the low-frequency input circuit connection end, a first electrode of the first transistor Q11 is used as an input end of an analog signal power supply Vcc, and a second electrode of the first transistor Q11 is connected with the high-frequency input buffer circuit output end; one end of the first constant current source I11 is connected with the second pole of the first transistor Q11, and the other end is used for being connected with a power supply Vee; the capacitor C12 is connected between the input end of the high-frequency input buffer circuit and the control electrode of the first transistor Q11;

and/or the feedback circuit comprises a resistor R14 and a resistor R15; the resistor R14 is connected between the first connection end of the feedback circuit and the ground GND; the resistor R15 is connected between the first connection end of the feedback circuit and the second connection end of the feedback circuit.

4. The wideband buffered analog switch circuit as claimed in claim 3, wherein said low frequency input circuit further comprises a capacitor C11 and a resistor R13; the capacitor C11 is connected between the negative input end of the operational amplifier U11 and the output end of the operational amplifier U11 and is used for compensating the amplitude-frequency response of the operational amplifier U11 and enabling the amplitude-frequency response to be flatter; a resistor R13 is connected between the output of the operational amplifier U11 and the low frequency input circuit output.

5. The wideband buffered analog switch circuit as claimed in claim 2, wherein said feedback switch circuit includes a first feedback switch sub-circuit and a resistor R21; the first feedback switch sub-circuit comprises a single-pole double-throw analog switch K21 and a resistor R22, and the single-pole double-throw analog switch K21 comprises a common terminal, a first terminal and a second terminal; the common terminal of the single-pole double-throw analog switch K21 is connected with the first common terminal of the feedback switch circuit; one end of the resistor R22 is connected with the first end of the single-pole double-throw analog switch K21, and the other end of the resistor R22 is connected with the first connecting end of the feedback switch circuit; the resistor R21 is connected between the second terminal of the single-pole double-throw analog switch K21 and the second connection terminal of the feedback switch circuit.

6. The wideband buffered analog switch circuit as defined in claim 5, wherein the feedback switch circuit further comprises a second feedback switch sub-circuit; the second feedback switch sub-circuit is the same as the first feedback switch sub-circuit; the common end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit is connected with the second common end of the feedback switch circuit, one end of a resistor R22 of the second feedback switch sub-circuit is connected with the first end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit, the other end of the resistor R22 of the second feedback switch sub-circuit is connected with the third connecting end of the feedback switch circuit, and the second end of the single-pole double-throw analog switch K21 of the second feedback switch sub-circuit is connected with the second end of the single-pole double-throw analog switch K21 of the first feedback switch sub-circuit.

7. The wideband buffered analog switch circuit as defined in claim 2, wherein the wideband switch circuit includes a current source circuit and a first switch bridge circuit; the current source circuit is used for providing a current source for the first switch bridge circuit;

the first switch bridge circuit comprises a first connection end of the switch bridge circuit, a second connection end of the switch bridge circuit, a first connection end of a current source and a second connection end of the current source; the first current source connecting end and the second current source connecting end are respectively connected with the current source circuit, and the first switch bridge circuit connecting end and the second switch bridge circuit connecting end are respectively connected with the first broadband switch circuit input end and the broadband switch circuit output end;

8. The wideband buffered analog switch circuit as defined in claim 7, wherein said first switch bridge circuit further comprises a second diode bridge circuit; the second diode bridge circuit is the same as the first diode bridge circuit; the first connecting end of the second diode bridge circuit is connected with the second connecting end of the first diode bridge circuit, the second connecting end of the second diode bridge circuit is connected with the first connecting end of the first diode bridge circuit, the third connecting end of the second diode bridge circuit is connected with the input end of the second broadband switch circuit, and the fourth connecting end of the second diode bridge circuit is connected with the third connecting end of the first diode bridge circuit.

9. The wideband buffered analog switch circuit as defined in claim 8, wherein said wideband switch circuit further includes an output circuit connected between said switch bridge circuit second connection terminal and said wideband switch circuit output terminal;

the output circuit comprises a second transistor Q31 and a fourth current source I33; a control electrode of the second transistor Q31 is connected with the second connection end of the switch bridge circuit, a first electrode of the second transistor Q31 is used as an input end of an analog signal power supply Vcc, and a second electrode of the second transistor Q31 is connected with the output end of the broadband switch circuit; one end of the fourth current source I33 is connected to the second pole of the second transistor Q31, and the other end is used for being connected to a power supply Vee;

and/or the first diode bridge circuit comprises a PIN diode.

10. A wideband buffered analog switch integrated circuit comprising the wideband buffered analog switch circuit of claim 1; the broadband buffering analog switch circuit comprises n first input buffering circuits, wherein the input end of each input buffering circuit is used as one input end of the broadband buffering analog switch circuit, and n is an integer greater than 1;

the broadband switch circuit comprises n first broadband switch circuit input ends and is respectively connected with n first output ends of the input buffer circuits; the broadband switch circuit is also used for providing a switching function for the electric signals output by the n first input buffer circuits;

the broadband switch circuit comprises a current source circuit and n first switch bridge circuits; the current source circuit is used for providing current sources for the n first switch bridge circuits;

the first switch bridge circuit comprises a first connection end of the switch bridge circuit, a second connection end of the switch bridge circuit, a first connection end of a current source and a second connection end of the current source; the first current source connecting end and the second current source connecting end are respectively connected with the current source circuits, the first switch bridge circuit connecting end of each first switch bridge circuit is connected with the input end of one first broadband switch circuit, and the second switch bridge circuit connecting end is connected with the output end of the broadband switch circuit;

the first switch bridge circuit comprises a single-pole double-throw analog switch K31, a single-pole double-throw analog switch K32 and a first diode bridge circuit; the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32 respectively comprise a common terminal, a first terminal and a second terminal; the first diode bridge circuit comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end, the first connecting end and the second connecting end of the first diode bridge circuit are respectively connected with the common ends of the single-pole double-throw analog switch K31 and the single-pole double-throw analog switch K32, and the third connecting end and the fourth connecting end of the first diode bridge circuit are respectively connected with the first connecting end of the switch bridge circuit and the second connecting end of the switch bridge circuit; the first end of the single-pole double-throw analog switch K31 is connected with the first end of the single-pole double-throw analog switch K32 and is connected with the first connection end of the current source; the second end of the single-pole double-throw analog switch K31 is connected with the second end of the single-pole double-throw analog switch K32 and is connected with the second connecting end of the current source;

the first diode bridge circuit comprises a resistor R31, a resistor R32, a diode D31, a diode D32, a diode D33 and a diode D34; one end of the resistor R31 is connected with the anodes of the diode D31 and the diode D33, the other end of the resistor R32 is connected with the first connection end of the first diode bridge circuit, one end of the resistor R32 is connected with the cathodes of the diode D32 and the diode D34, the other end of the resistor R32 is connected with the second connection end of the first diode bridge circuit, the cathode of the diode D31 and the anode of the diode D32 are connected with the third connection end of the first diode bridge circuit, and the cathode of the diode D33 and the anode of the diode D34 are connected with the fourth connection end of the first diode bridge circuit;

the feedback switch circuit comprises n first connecting ends and is respectively connected with the first output ends of the n input buffer circuits; the input buffer circuit also comprises n first common ends which are respectively connected with the feedback input ends of the input buffer circuit; the feedback switch circuit is also used for providing a switch switching control function for the n electric signals output by the first input buffer circuits.