High-gain mixer and communication equipment
By connecting the input inductors in the RF input stage to form series resonance, the problem of gain improvement of active mixers in the millimeter wave band in the prior art is solved, and the gain improvement of efficient and low power consumption is achieved, reducing the design difficulty.
Patent Information
- Application Number
- CN202411509175.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-02-21
AI Technical Summary
The prior art is difficult to effectively improve gain in millimeter wave band active mixers. Traditional methods such as increasing current or output impedance will lead to increased power consumption and noise deterioration, and the design difficulty will increase, which will not meet the actual use needs.
The gain of the mixer is increased by connecting the inductor in series in the RF input stage to form a series resonance to amplify the input RF voltage signal. The design does not require additional power consumption, is simple in structure, flexible in regulation, and is insensitive to process and temperature effects.
It realizes that the gain of the mixer is improved without increasing power consumption and complexity, meets the need to improve gain, and reduces the design difficulty.
Smart Images
Figure CN119496467A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of integrated circuits, and in particular to a high-gain mixer and communication equipment. Background Art
[0002] Mixers are often used in transceiver architectures because of their frequency conversion capabilities. With the rapid development of wireless communication technology, the performance of mixers directly affects the overall performance of the entire transceiver system. As one of the important components of transceivers, mixers are subject to increasingly stringent performance requirements.
[0003] The basic theory of a mixer is to multiply two input signals through nonlinearity, and obtain the sum and difference frequency signals of the two signals at the output. Different from the gain of an amplifier, since a mixer is a three-port device and the frequencies of the input and output signals are different, conversion gain or conversion loss is usually used to describe the amplification or attenuation of a mixer.
[0004] To a certain extent, the size of the mixer's conversion gain can determine the dynamic operating range of the receiver's overall circuit. In the down-conversion structure, the mixer needs to have a certain conversion gain to reduce the impact of the subsequent stage noise on the overall receiver noise figure, and it can also reduce the gain requirement of the previous stage LNA (Low Noise Amplifier). If the mixer's conversion gain is too small, the noise of subsequent circuit modules will be difficult to suppress.
[0005] At present, there are two main methods for increasing the gain of active mixers in the millimeter wave band: one is to increase the current of the mixer; the other is to increase the output impedance of the mixer, that is, to increase the resonant impedance of the mixer load LC oscillation. These two methods are relatively rough and simple, but they will inevitably bring other effects: for example, increasing the mixing current will inevitably increase the power consumption of the chip and also cause the deterioration of noise; increasing the resonant impedance of the LC oscillation will inevitably reduce the bandwidth coverage of the mixer, making the circuit gain very sensitive to factors such as process, layout, and temperature. On the other hand, it reversely increases the difficulty of mixer design.
[0006] Therefore, the above-mentioned current method of increasing the mixer gain is difficult to meet the actual use requirements of the mixer. Summary of the invention
[0007] In view of this, an object of the present invention is to provide a high-gain mixer and a communication device to alleviate the above technical problems.
[0008] In a first aspect, an embodiment of the present invention provides a high-gain mixer, comprising: an RF input stage, a local oscillator input stage and a load output stage connected in sequence; wherein the RF input stage is used to input an RF voltage signal, convert the RF voltage signal into a current signal, and input the current signal to the local oscillator input stage; the local oscillator input stage is used to input a local oscillator signal, and mix the current signal input by the RF input stage with the local oscillator signal to obtain a mixed RF output signal, and transmit the mixed signal to the load output stage; the load output stage is used to output the mixed RF output signal; wherein the RF input stage comprises an input end, and a transconductance unit connected to the input end; an input inductor is provided in series with the input end, and the input inductor is used to generate series resonance at the input end to amplify the input RF voltage signal.
[0009] In combination with the first aspect, an embodiment of the present invention provides a first possible implementation of the first aspect, wherein the above-mentioned input end includes a P input end and an N input end; the input inductor includes a first input inductor connected in series with the P input end and a second input inductor connected in series with the N input end.
[0010] In combination with the first possible implementation of the first aspect, an embodiment of the present invention provides a second possible implementation of the first aspect, wherein the above-mentioned transconductance unit includes a first transconductance transistor and a second transconductance transistor corresponding to the P input terminal, and a third transconductance transistor and a fourth transconductance transistor corresponding to the N input terminal; wherein the gates of the first transconductance transistor and the second transconductance transistor are connected to the P input terminal, the sources are grounded, and the drains are connected to the local oscillator input stage; the gates of the third transconductance transistor and the fourth transconductance transistor are connected to the N input terminal, the sources are grounded, and the drains are connected to the local oscillator input stage.
[0011] In combination with the second possible implementation of the first aspect, an embodiment of the present invention provides a third possible implementation of the first aspect, wherein the above-mentioned local oscillator input stage includes: a first input switch tube and a second input switch tube corresponding to the P input end, and a third input switch tube and a fourth input switch tube corresponding to the N input end; wherein the first input switch tube and the third input switch tube form an I-way unit for inputting the I-way signal of the local oscillator signal; the source of the first input switch tube is connected to the drain of the first transconductance transistor; the source of the third input switch tube is connected to the drain of the third transconductance transistor; wherein the second input switch tube and the fourth input switch tube form a Q-way unit for inputting the Q-way signal of the local oscillator signal; the source of the second input switch tube is connected to the drain of the second transconductance transistor; the source of the fourth input switch tube is connected to the drain of the fourth transconductance transistor.
[0012] In combination with the third possible implementation of the first aspect, an embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein the first input switch tube includes a first switch tube and a second switch tube; the third input switch tube includes a third switch tube and a fourth switch tube; the source of the first switch tube and the second switch tube is connected to the drain of the first transconductance transistor; the source of the third switch tube and the fourth switch tube is connected to the drain of the third transconductance transistor; the gate of the second switch tube and the third switch tube is connected and used to input the N-end signal of the I-path signal; the gate of the first switch tube and the fourth switch tube is used to input the P-end signal of the I-path signal; wherein the drain of the first switch tube and the third switch tube is merged and connected to the load output stage; the second switch tube and the The drain of the fourth switch tube is merged and connected to the load output stage; the fourth input switch tube includes a fifth switch tube and a sixth switch tube; the second input switch tube includes a seventh switch tube and an eighth switch tube; the source of the fifth switch tube and the sixth switch tube is connected to the drain of the fourth transconductance transistor; the source of the seventh switch tube and the eighth switch tube is connected to the drain of the second transconductance transistor; the gate of the sixth switch tube and the seventh switch tube is connected and used to input the N-end signal of the Q-path signal; the gate of the fifth switch tube and the eighth switch tube is used to input the P-end signal of the Q-path signal; wherein, the drain of the fifth switch tube and the seventh switch tube is merged and connected to the load output stage; the drain of the sixth switch tube and the eighth switch tube is merged and connected to the load output stage.
[0013] In combination with the fourth possible implementation of the first aspect, an embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein the parameters of the first transconductance transistor, the second transconductance transistor, the third transconductance transistor and the fourth transconductance transistor are exactly the same; the parameters of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are exactly the same.
[0014] In combination with the fourth possible implementation of the first aspect, an embodiment of the present invention provides a sixth possible implementation of the first aspect, wherein the above-mentioned load output stage includes a Cascode stage and a load stage connected in sequence; wherein the Cascode stage is connected to the local oscillator input stage, and the load stage is connected to the output port of the high gain mixer.
[0015] In combination with the sixth possible implementation of the first aspect, an embodiment of the present invention provides a seventh possible implementation of the first aspect, wherein the above-mentioned Cascode stage includes multiple Cascode tubes, and the gates of the multiple Cascode tubes are connected to a preset bias voltage; wherein the multiple Cascode tubes include a first Cascode tube, a second Cascode tube, a third Cascode tube and a fourth Cascode tube; the drains of the first switch tube and the third switch tube are merged and connected to the output end of the load stage through the first Cascode tube; the drains of the second switch tube and the fourth switch tube are merged and connected to the output end of the load stage through the second Cascode tube; the drains of the fifth switch tube and the seventh switch tube are merged and connected to the output end of the load stage through the third Cascode tube; the drains of the sixth switch tube and the eighth switch tube are merged and connected to the output end of the load stage through the fourth Cascode tube.
[0016] In combination with the sixth possible implementation of the first aspect, an embodiment of the present invention provides an eighth possible implementation of the first aspect, wherein the above-mentioned load level includes a first output load corresponding to the I-path unit and a second output load corresponding to the Q-path unit; the first output load and the second output load are LC oscillation output loads.
[0017] In a second aspect, an embodiment of the present invention further provides a communication device, wherein the communication device is configured with the high-gain mixer described in the first aspect.
[0018] The embodiments of the present invention bring the following beneficial effects:
[0019] The high-gain mixer and communication equipment provided by the embodiments of the present invention include, in the high-gain mixer, a radio frequency input stage, a local oscillator input stage and a load output stage connected in sequence; wherein the radio frequency input stage includes an input terminal and a transconductance unit connected to the input terminal; an input inductor is arranged in series at the input terminal, and the input inductor is used to generate series resonance at the input terminal to amplify the input radio frequency voltage signal, and the entire structure does not need to increase additional power consumption, and the voltage swing of the input terminal can be achieved only by the input inductor, thereby improving the gain of the mixer, and the overall circuit structure is simple, flexible to adjust, and insensitive to the influence of process and temperature, thereby meeting the need for improving the gain without affecting the performance of the mixer.
[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.
[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.
[0023] Figure 1 A structural block diagram of a high-gain mixer provided by an embodiment of the present invention;
[0024] Figure 2 A circuit diagram of a high-gain mixer provided by an embodiment of the present invention;
[0025] Figure 3 A schematic diagram of an equivalent circuit of a radio frequency input stage provided by an embodiment of the present invention. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.
[0027] At present, the method of increasing the gain of the mixer, especially the active mixer in the millimeter wave band, is mainly achieved by increasing the current of the mixer and increasing the output impedance of the mixer. This method not only affects the performance of the mixer, but also increases the design difficulty of the mixer, making it difficult to meet the actual use requirements of the mixer.
[0028] Based on this, a high-gain mixer and a communication device provided in an embodiment of the present invention can effectively alleviate the above technical problems.
[0029] To facilitate understanding of this embodiment, a high-gain mixer disclosed in an embodiment of the present invention is first introduced in detail.
[0030] In a possible implementation manner, an embodiment of the present invention provides a high-gain mixer, hereinafter referred to as a mixer, specifically, Figure 1The structure block diagram of a high-gain mixer is shown. The high-gain mixer provided by the embodiment of the present invention includes a radio frequency input stage 10, a local oscillator input stage 20 and a load output stage 30 connected in sequence.
[0031] Among them, the RF input stage 10 is used to input an RF voltage signal, convert the RF voltage signal into a current signal, and input it to the local oscillator input stage 20; the local oscillator input stage 20 is used to input a local oscillator signal, and mix the current signal input by the RF input stage 10 with the local oscillator signal to obtain a mixed RF output signal, and transmit it to the load output stage 30; the load output stage 30 is used to output the mixed RF output signal.
[0032] Further, if Figure 1 As shown, the RF input stage 10 includes an input terminal 101 and a transconductance unit 102 connected to the input terminal 101; the input terminal 101 is provided with an input inductor 103 in series, and the input inductor 103 is used to generate series resonance at the input terminal to amplify the input RF voltage signal.
[0033] The high-gain mixer provided by the embodiment of the present invention includes a radio frequency input stage, a local oscillator input stage and a load output stage connected in sequence; wherein the radio frequency input stage includes an input terminal and a transconductance unit connected to the input terminal; an input inductor is arranged in series at the input terminal, and the input inductor is used to generate series resonance at the input terminal to amplify the input radio frequency voltage signal, and the entire structure does not need to increase additional power consumption, and the voltage swing of the input terminal can be achieved only by the input inductor, thereby improving the gain of the mixer, and the overall circuit structure is simple, flexible to adjust, and insensitive to the influence of process and temperature, thereby meeting the need for improving the gain without affecting the performance of the mixer.
[0034] In actual use, in order to facilitate inputting the RF voltage signal at the RF input stage, usually, the input end of the RF input stage includes a P input end and an N input end, which are used to input the positive voltage signal and the negative voltage signal of the RF voltage signal respectively. The above-mentioned input inductor includes a first input inductor connected in series to the P input end and a second input inductor connected in series to the N input end.
[0035] For ease of understanding, Figure 1 On the basis of Figure 2 A circuit diagram of a high gain mixer is shown in FIG. Figure 2 As shown, inductors L1 and L2 represent the first input inductor and the second input inductor respectively, and the corresponding RF_P and RF_N are the RF input terminals of the mixer, ie, the P input terminal and the N input terminal in the embodiment of the present invention.
[0036] Furthermore, the transconductance unit connected to the input terminal includes a first transconductance transistor and a second transconductance transistor corresponding to the P input terminal, and a third transconductance transistor and a fourth transconductance transistor corresponding to the N input terminal.
[0037] in, Figure 2 In the embodiment, transistors M1 and M4 are respectively a first transconductance transistor and a second transconductance transistor, and, as Figure 2 As shown, the gates of the first transconductance transistor M1 and the second transconductance transistor M4 are connected to the P input terminal, the sources are grounded, and the drains are connected to the above-mentioned local oscillator input stage.
[0038] further, Figure 2 In the figure, transistors M2 and M3 represent a third transconductance transistor and a fourth transconductance transistor respectively. Specifically, the gates of the third transconductance transistor M2 and the fourth transconductance transistor M3 are connected to the N input terminal, the sources are grounded, and the drains are connected to the local oscillator input stage.
[0039] In a specific implementation, the RF input stage is used as the RF input terminal, the transistors M1 to M4 are also called input tubes, and the parasitic capacitances of the first input inductor L1 and the second input inductor L2 and the input tubes M1 to M4 can form a series resonance, so that the RF voltage signal inputted by the input terminals RF_P and RF_N is Figure 2 The vp and vn points in the circuit are amplified, that is, the voltage swing at the gate end of the mixer's input tubes M1 to M4 is increased, so the voltage swing at the mixer's output port is also increased, thereby increasing the mixer's gain.
[0040] The input tubes M1 to M4 in the embodiment of the present invention are described by taking MOS tubes as an example, and their specific models and parameters can be set according to actual usage conditions, which are not limited in the embodiment of the present invention.
[0041] Further, for ease of understanding, Figure 3 Also shown is a schematic diagram of an equivalent circuit of a radio frequency input stage, such as Figure 3 As shown, it specifically shows an equivalent circuit schematic diagram of a series resonance generated by the parasitic capacitance of the input tubes M1 to M4 after the input inductor is connected in series at the input end of the RF input stage.
[0042] like Figure 3 As shown, the capacitance to ground seen from the vp point is the parallel connection between the parasitic capacitance to ground cgs1+cgb1 of the gate of the input tube M1 and the parasitic capacitance to ground cgs4+cgb4 of the gate of M4;
[0043] Wherein, cgs1 is the parasitic capacitance between the gate and source of the input tube M1, cgb1 is the parasitic capacitance between the gate and substrate of the input tube M1, cgs4 is the parasitic capacitance between the gate and source of the input tube M4, and cgb4 is the parasitic capacitance between the gate and substrate of the input tube M4;
[0044] The equivalent capacitance of the above parallel capacitor to ground is denoted by c p .
[0045] Furthermore, the capacitance to ground seen from point vn is the parallel connection of the parasitic capacitance to ground of the gate of input tube M2, cgs2+cgb2, and the parasitic capacitance to ground of the gate of input tube M3, cgs3+cgb3. The equivalent capacitance is denoted as c n .
[0046] Among them, cgs2 is the parasitic capacitance between the gate and source of the input tube M2, cgb2 is the parasitic capacitance between the gate of the input tube M2 and the substrate, cgs3 is the parasitic capacitance between the gate and source of the input tube M3, and cgb3 is the parasitic capacitance between the gate of the input tube M3 and the substrate.
[0047] Further, using the principle of unilateral circuit analysis, we can analyze Figure 3 In the figure, after the input RF voltage at the RF_P terminal passes through the LC series resonance (the LC series resonance composed of the output inductor and the above-mentioned capacitance to ground), the voltage swing that falls on the input tube gate terminal is the voltage swing at the vp point.
[0048] If the RF voltage signal at the input RF_P port is Vin, when resonating, the inductive reactance of the inductor and the capacitive reactance of the capacitor cancel each other out, and the total current is:
[0049]
[0050] Among them, R is the pure electrical impedance seen by the input terminal RF_P, which is generally the parasitic resistance of the inductor and signal trace.
[0051] It is also known that the quality factor Q of LC series resonance is equal to:
[0052]
[0053] Therefore, the voltage at point vp can be expressed as:
[0054]
[0055] Where w0 represents the equivalent capacitance c p The angular frequency of , j is the imaginary unit.
[0056] After taking the absolute value, it is expressed as:
[0057]
[0058] Therefore, after the excitation voltage Vin (ie, the above-mentioned RF voltage signal Vin) of the input terminal RF_P undergoes LC series resonance, the voltage swing obtained at the gate of the input tube increases by Q times, where the quality factor Q is a number greater than 1.
[0059] Since the voltage at the output of the mixer is expressed as:
[0060] Voutt=Vin*Q*Gm*Rout
[0061] Where Gm is the transconductance of the mixer, and Rout is the output impedance of the mixer;
[0062] Therefore, the mixer gain is expressed as:
[0063]
[0064] Among them, 20log(GmRou t ) is the original gain of the mixer. It can be seen from the above formula that the LC series resonance increases the gain of the mixer by 20*logQ dB, that is, the above-mentioned RF input stage in the embodiment of the present invention improves the gain of the mixer.
[0065] Furthermore, the local oscillator input stage in the embodiment of the present invention includes: a first input switch tube and a second input switch tube corresponding to the P input terminal, and a third input switch tube and a fourth input switch tube corresponding to the N input terminal.
[0066] The first input switch tube and the third input switch tube form an I-channel unit for inputting an I-channel signal of a local oscillator signal; the source of the first input switch tube is connected to the drain of the first transconductance transistor; the source of the third input switch tube is connected to the drain of the third transconductance transistor;
[0067] Among them, the above-mentioned second input switch tube and the fourth input switch tube form a Q-path unit, which is used to input the Q-path signal of the local oscillator signal; the source of the second input switch tube is connected to the drain of the second transconductance transistor; the source of the fourth input switch tube is connected to the drain of the fourth transconductance transistor.
[0068] Specifically, Figure 2 As shown, the first input switch tube includes a first switch tube M5 and a second switch tube M6; the third input switch tube includes a third switch tube M7 and a fourth switch tube M8;
[0069] The source of the first switch tube M5 and the second switch tube M6 are connected to the drain of the first transconductance transistor M1; the source of the third switch tube M7 and the fourth switch tube M8 are connected to the drain of the third transconductance transistor M2, and the gate of the second switch tube M6 and the third switch tube M7 are connected and used to input the N-end signal of the I-way signal, that is, Figure 2 The gates of the first switch tube M5 and the fourth switch tube M8 are used to input the P-terminal signal of the I-way signal, that is, Figure 2 The signal represented by LO_IP.
[0070] Furthermore, the drains of the first switch tube M5 and the third switch tube M7 are combined and connected to the load output stage; the drains of the second switch tube M6 and the fourth switch tube M8 are combined and connected to the load output stage.
[0071] Similarly, Figure 2 In the embodiment, the fourth input switch tube includes a fifth switch tube M9 and a sixth switch tube M10; the second input switch tube includes a seventh switch tube M11 and an eighth switch tube M12.
[0072] The sources of the fifth switch tube M9 and the sixth switch tube M10 are connected to the drain of the fourth transconductance transistor M3 ; the sources of the seventh switch tube M11 and the eighth switch tube M12 are connected to the drain of the second transconductance transistor M4 .
[0073] Furthermore, the gates of the sixth switch tube M10 and the seventh switch tube M11 are connected and used to input the N-terminal signal of the Q-path signal, that is, Figure 2 The gates of the fifth switch tube M9 and the eighth switch tube M12 are used to input the P-terminal signal of the Q-path signal, that is, Figure 2 The signal represented by LO_QP in ;
[0074] The drains of the fifth switch tube M9 and the seventh switch tube M11 are combined and connected to the load output stage; the drains of the sixth switch tube M10 and the eighth switch tube M12 are combined and connected to the load output stage.
[0075] Furthermore, the above Figure 2 , the parameters of the first transconductance transistor M1, the second transconductance transistor M4, the third transconductance transistor M2 and the fourth transconductance transistor M4 are exactly the same; the parameters of the first switch tube M5, the second switch tube M6, the third switch tube M7, the fourth switch tube M8, the fifth switch tube M9, the sixth switch tube M10, the seventh switch tube M11 and the eighth switch tube M12 are exactly the same.
[0076] Furthermore, the load output stage in the embodiment of the present invention comprises a cascode stage and a load stage connected in sequence; wherein the cascode stage is connected to the local oscillator input stage, and the load stage is connected to the output port of the high gain mixer.
[0077] Specifically, the Cascode stage includes a Cascode structure composed of multiple Cascode tubes, also referred to as a CAS structure, and the gates of the multiple Cascode tubes are connected to a preset bias voltage, that is, Figure 2 VB in. Among them, such as Figure 2 As shown, the plurality of cascode tubes include a first cascode tube M13, a second cascode tube M14, a third cascode tube M15 and a fourth cascode tube M16, and the parameters of the plurality of cascode tubes M13-M16 are completely the same.
[0078] The drains of the first switch tube M5 and the third switch tube M7 are combined and connected to the output end of the load stage through the first Cascode tube M13; the drains of the second switch tube M6 and the fourth switch tube M8 are combined and connected to the output end of the load stage through the second Cascode tube M14; the drains of the fifth switch tube M9 and the seventh switch tube M11 are combined and connected to the output end of the load stage through the third Cascode tube M15; the drains of the sixth switch tube M10 and the eighth switch tube M12 are combined and connected to the output end of the load stage through the fourth Cascode tube M16.
[0079] Further, if Figure 2 As shown, the first cascode tube M13 and the second cascode tube M14 correspond to the I-channel unit, the third cascode tube M15 and the fourth cascode tube M16 correspond to the Q-channel unit, and the load stage in the embodiment of the present invention also includes a first output load corresponding to the I-channel unit and a second output load corresponding to the Q-channel unit; the first output load and the second output load are LC oscillation output loads.
[0080] Specifically, Figure 2 In the embodiment, the first output load includes capacitors C1, C2 and a differential inductor L3 with a tap, and the tap of L3 is connected to VDD, and the second output load includes capacitors C3, C4 and a differential inductor L4 with a tap, and the tap of L4 is connected to VDD.
[0081] In actual use, the LC oscillation output load composed of C1, C2, and L3 serves as the output load of the mixer I path, and the LC oscillation output load composed of C3, C4, and L4 serves as the output load of the mixer Q path.
[0082] In summary, combined Figure 2 As shown in the circuit diagram, the entire circuit of the high-gain mixer in the embodiment of the present invention includes the RF input stage 10 and the local oscillator input stage 20 corresponding to the dotted box, and the load output stage includes the cascode stage 301 and the load stage 302:
[0083] L1 and L2 are input inductors connected in series with the P input terminal and the N input terminal of the RF input respectively; M1-M4 are transconductance transistors of the RF input stage, also called GM tubes, where GM is transconductance; M5-M8 are switching tubes of the I input of the local oscillator input stage LO; M9-M12 are switching tubes of the Q input of the local oscillator input stage LO; M13-M16 are Cascode tubes of the mixer, connected in a common source and common gate manner, and the parameters of M1-M4 are exactly the same, the parameters of M5-M12 are exactly the same; the parameters of M13-M16 are exactly the same; C1, C2, and L3 constitute the first output load; C3, C4, and L4 constitute the second output load.
[0084] further, Figure 2 In the figure, RF_P and RF_N serve as the RF input terminals of the mixer, LO_IP is the P-terminal input signal of the local oscillator signal I of the local oscillator input stage, LO_IN is the N-terminal input signal of the local oscillator signal I, LO_QP is the P-terminal input signal of the local oscillator signal Q, and LO_QN is the N-terminal input signal of the local oscillator signal Q; VB represents the bias voltage of the cascode tube; IF_IP is the P-terminal output signal of the intermediate frequency signal I of the mixer, IF_IN is the N-terminal output signal of the intermediate frequency signal I, IF_QP is the P-terminal output of the intermediate frequency signal Q, and IF_QN is the N-terminal output of the intermediate frequency signal Q.
[0085] Figure 2 In the embodiment, the first transconductance transistor M1 and the second transconductance transistor M4 at the P input end are respectively connected to the switch tubes M5 and M6 of the local oscillation signal I input and the switch tubes M11 and M12 of the Q input, and the connection points are respectively as shown in FIG. Figure 2 A and D in the N input terminal of the third transconductance transistor M2 and the fourth transconductance transistor M3 are respectively connected to the local oscillation signal I input switch tube M7, M8 and Q input switch tube M9, M10, the connection points are respectively as Figure 2 B and C in.
[0086] The drain terminals (drains) of M5 and M7 are combined and connected to the output terminal IF_IP through the first Cascode tube M13, the drain terminals (drains) of M6 and M8 are combined and connected to the output terminal IF_IN through the second Cascode tube M14, the drain terminals (drains) of M9 and M11 are combined and connected to the output terminal IF_QN through the third Cascode tube M15, and the drain terminals (drains) of M10 and M12 are combined and connected to the output terminal IF_QP through the fourth Cascode tube M16.
[0087] Based on the above Figure 2In the circuit diagram of the mixer shown in the figure, the RF voltage signal is input from M1 to M4 through the input inductors L1 and L2, and then converted into a current signal and sent to the input switch tubes M5 to M12 of the local oscillator signal respectively to mix with the local oscillator signal. The RF output signal generated after mixing is sent to the output end through the CAS tubes M13 to M16.
[0088] At the RF input end, the input inductors L1, L2 and the parasitic capacitance of the input tubes M1 to M4 form a series resonance, so that the input RF voltage signal is amplified at the vp and vn points, that is, the voltage swing at the gate end of the mixer input tubes M1 to M4 is increased, so the voltage swing at the mixer output port is also increased, thereby improving the gain of the mixer.
[0089] Therefore, the high-gain mixer provided in the embodiment of the present invention can connect an inductor in series at the input end of the mixer in the millimeter wave frequency band to generate parallel resonance with the parasitic capacitance of the input tube, amplify the input RF voltage signal, and thus improve the gain of the mixer. This design of the embodiment of the present invention cleverly utilizes the parasitic capacitance of the input tube, and the design method is practical, which can improve the gain of the mixer without increasing the extra power consumption and the complexity of the circuit design.
[0090] Furthermore, an embodiment of the present invention also provides a communication device, which is equipped with the high-gain mixer provided by the above embodiment.
[0091] The communication device provided in the embodiment of the present invention has the same technical features as the high-gain mixer provided in the above embodiment, and can therefore solve the same technical problems and achieve the same technical effects.
[0092] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the communication device described above can refer to the corresponding process in the aforementioned embodiment, and will not be repeated here.
[0093] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0094] If the functions are implemented in the form of 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 the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.
[0095] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0096] Finally, it should be noted that the above embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.
Claims
1. A high gain mixer, characterized in that: include: A radio frequency input stage, a local oscillator input stage and a load output stage connected in sequence; The RF input stage is used to input a RF voltage signal, convert the RF voltage signal into a current signal, and input the current signal into the local oscillator input stage; The local oscillator input stage is used to input a local oscillator signal, and mix the current signal input by the radio frequency input stage with the local oscillator signal to obtain a mixed radio frequency output signal, and transmit it to the load output stage; The load output stage is used to output the mixed RF output signal; Wherein, the radio frequency input stage includes an input end, and a transconductance unit connected to the input end; An input inductor is arranged in series at the input end, and the input inductor is used to generate series resonance at the input end to amplify the input radio frequency voltage signal.
2. The high gain mixer according to claim 1, characterized in that: The input terminal includes a P input terminal and an N input terminal; The input inductor includes a first input inductor connected in series with the P input terminal and a second input inductor connected in series with the N input terminal.
3. The high gain mixer according to claim 2, characterized in that: The transconductance unit includes a first transconductance transistor and a second transconductance transistor corresponding to the P input terminal, and a third transconductance transistor and a fourth transconductance transistor corresponding to the N input terminal; Wherein, the gates of the first transconductance transistor and the second transconductance transistor are connected to the P input terminal, the sources are grounded, and the drains are connected to the local oscillator input stage; The gates of the third transconductance transistor and the fourth transconductance transistor are connected to the N input terminal, the sources are grounded, and the drains are connected to the local oscillator input stage.
4. The high gain mixer according to claim 3, characterized in that: The local oscillator input stage includes: a first input switch tube and a second input switch tube corresponding to the P input terminal, and a third input switch tube and a fourth input switch tube corresponding to the N input terminal; Wherein, the first input switch tube and the third input switch tube form an I-way unit, which is used to input the I-way signal of the local oscillator signal; the source of the first input switch tube is connected to the drain of the first transconductance transistor; the source of the third input switch tube is connected to the drain of the third transconductance transistor; Among them, the second input switch tube and the fourth input switch tube form a Q-path unit, which is used to input the Q-path signal of the local oscillator signal; the source of the second input switch tube is connected to the drain of the second transconductance transistor; the source of the fourth input switch tube is connected to the drain of the fourth transconductance transistor.
5. The high gain mixer according to claim 4, characterized in that: The first input switch tube includes a first switch tube and a second switch tube; the third input switch tube includes a third switch tube and a fourth switch tube; The source electrodes of the first switch tube and the second switch tube are connected to the drain electrode of the first transconductance transistor; the source electrodes of the third switch tube and the fourth switch tube are connected to the drain electrode of the third transconductance transistor; The gates of the second switch tube and the third switch tube are connected and used to input the N-end signal of the I-way signal; the gates of the first switch tube and the fourth switch tube are used to input the P-end signal of the I-way signal; Wherein, the drains of the first switch tube and the third switch tube are combined and connected to the load output stage; the drains of the second switch tube and the fourth switch tube are combined and connected to the load output stage; The fourth input switch tube includes a fifth switch tube and a sixth switch tube; the second input switch tube includes a seventh switch tube and an eighth switch tube; The source electrodes of the fifth switch tube and the sixth switch tube are connected to the drain electrode of the fourth transconductance transistor; the source electrodes of the seventh switch tube and the eighth switch tube are connected to the drain electrode of the second transconductance transistor; The gates of the sixth switch tube and the seventh switch tube are connected and used to input the N-end signal of the Q-path signal; the gates of the fifth switch tube and the eighth switch tube are used to input the P-end signal of the Q-path signal; Among them, the drains of the fifth switch tube and the seventh switch tube are combined and connected to the load output stage; the drains of the sixth switch tube and the eighth switch tube are combined and connected to the load output stage.
6. The high gain mixer according to claim 5, characterized in that: The parameters of the first transconductance transistor, the second transconductance transistor, the third transconductance transistor and the fourth transconductance transistor are completely the same; Parameters of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are completely the same.
7. The high gain mixer according to claim 5, characterized in that: The load output stage includes a cascode stage and a load stage connected in sequence; The cascode stage is connected to the local oscillator input stage, and the load stage is connected to the output port of the high-gain mixer.
8. The high gain mixer according to claim 7, characterized in that: The cascode stage includes a plurality of cascode tubes, and the gates of the plurality of cascode tubes are connected to a preset bias voltage; Wherein, the plurality of Cascode tubes include a first Cascode tube, a second Cascode tube, a third Cascode tube and a fourth Cascode tube; The drains of the first switch tube and the third switch tube are merged and connected to the output end of the load stage through the first Cascode tube; The drains of the second switch tube and the fourth switch tube are merged and connected to the output end of the load stage through the second Cascode tube; The drains of the fifth switch tube and the seventh switch tube are merged and connected to the output end of the load stage through the third Cascode tube; The drains of the sixth switch tube and the eighth switch tube are merged and connected to the output end of the load stage through the fourth Cascode tube.
9. The high gain mixer according to claim 7, characterized in that: The load stage includes a first output load corresponding to the I-path unit and a second output load corresponding to the Q-path unit; The first output load and the second output load are LC oscillation output loads.
10. A communication device, characterized in that: The communication device is provided with the high-gain mixer according to any one of claims 1 to 9.