Mixer correction circuit and mixer

Abstract

The invention provides a mixer correction circuit and a mixer, and relates to the technical field of integrated circuits, the mixer correction circuit comprises an intermediate frequency input stage, a local oscillator input stage and a load stage which are connected in sequence; the intermediate frequency input stage comprises a first input transconductance unit and a second input transconductance unit; the local oscillator input stage comprises a first local oscillator input unit and a second local oscillator input unit; transconductance transistors included in the first input transconductance unit and the second input transconductance unit are respectively provided with a current adjusting array. The current adjustment array is used for suppressing current deviation of the first input transconductance unit and the second input transconductance unit. According to the mixer correction circuit and the mixer provided by the invention, the current deviation is suppressed through the current adjustment array, the current balance of the transconductance transistor of the mixer can be realized, local oscillation signals are effectively prevented from leaking to an intermediate frequency end and a radio frequency end, and the use requirements of the mixer can be met under the condition that the performance of the mixer is not influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a mixer correction circuit and a mixer. Background Art

[0002] With the development of wireless communication technology, wireless signals transmitted over the air interface carry higher and higher data information capacity, and the wireless frequency increases to tens of GHz or even THz. This puts forward new requirements for the circuit design and indicators of the RF front-end. For example, in the transmitter, the baseband signal needs to be up-converted to a carrier signal in the millimeter wave band; in the receiver, the higher carrier signal needs to be converted to a baseband signal for processing, and so on.

[0003] In this frequency conversion process, a mixer is needed to achieve it. The mixer completes the up-conversion or down-conversion of the signal by adding or subtracting the input signal and the local oscillator signal. But in fact, due to factors such as MOS tube parasitic effects and substrate effects, the signal output by the mixer contains not only the required useful signal, but also the local oscillator signal. The leaked local oscillator signal will interfere with the useful signal, thereby affecting the performance of the transceiver.

[0004] At present, the main method to suppress the leakage of the local oscillator signal from the input to the output is to use a notch filter or a band-stop filter to weaken the signal at the local oscillator frequency, thereby reducing the impact of its leakage to the output. Although this method has a certain inhibitory effect on the leakage of the local oscillator, the design of this filter is greatly affected by the device process level, and the design is difficult and costly. At the same time, when the local oscillator signal and the output RF signal are similar, it is difficult to effectively filter out the leakage signal of the local oscillator signal, and it is difficult to meet the actual use requirements of the mixer. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a mixer calibration circuit and a mixer to alleviate the above technical problems.

[0006] In the first aspect, an embodiment of the present invention provides a mixer correction circuit, comprising: an intermediate frequency input stage, a local oscillator input stage and a load stage connected in sequence; the intermediate frequency input stage comprises a first input transconductance unit and a second input transconductance unit; the first input transconductance unit is used to input an intermediate frequency I-path signal, and the second input transconductance unit is used to input an intermediate frequency Q-path signal; the local oscillator input stage is used to input a local oscillator signal, wherein the local oscillator input stage comprises a first local oscillator input unit and a second local oscillator input unit; the first local oscillator input unit is connected to the first input transconductance unit, and the second local oscillator input unit is connected to the second input transconductance unit; the load stage comprises a radio frequency output terminal, which is used to output a radio frequency signal; wherein the transconductance transistors included in the first input transconductance unit and the second input transconductance unit are respectively configured with a current adjustment array; the current adjustment array is used to suppress the current deviation of the first input transconductance unit and the second input transconductance unit.

[0007] In combination with the first aspect, an embodiment of the present invention provides a first possible implementation manner of the first aspect, wherein the transconductance transistor included in the above-mentioned first input transconductance unit includes a first transconductance transistor and a second transconductance transistor; wherein the sources of the first transconductance transistor and the second transconductance transistor are grounded; the gate of the first transconductance transistor is used to input the P-end signal of the intermediate frequency I-channel signal, and the gate of the second transconductance transistor is used to input the N-end signal of the intermediate frequency I-channel signal; the drain of the first transconductance transistor and the drain of the second transconductance transistor are respectively connected to the first local oscillator input unit.

[0008] 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 current adjustment array of the above-mentioned first transconductance transistor includes at least one first adjustment branch connected in parallel with the first transconductance transistor; the first adjustment branch includes a switch tube, and a switch connected in series with the switch tube; wherein the gate of the switch tube is connected to the gate of the first transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate and drain of the first transconductance transistor; the current adjustment array of the second transconductance transistor includes at least one second adjustment branch connected in parallel with the second transconductance transistor; the second adjustment branch includes a switch tube, and a switch connected in series with the switch tube; wherein the gate of the switch tube is connected to the gate of the second transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate and drain of the second transconductance transistor.

[0009] In combination with the first aspect, an embodiment of the present invention provides a third possible implementation manner of the first aspect, wherein the transconductance transistor included in the above-mentioned second input transconductance unit includes a third transconductance transistor and a fourth transconductance transistor; wherein the sources of the third transconductance transistor and the fourth transconductance transistor are grounded; the gate of the third transconductance transistor is used to input the P-end signal of the intermediate frequency Q-path signal, and the gate of the fourth transconductance transistor is used to input the N-end signal of the intermediate frequency Q-path signal; the drain of the third transconductance transistor and the drain of the fourth transconductance transistor are respectively connected to the second local oscillator input unit.

[0010] 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 current adjustment array of the third transconductance transistor includes at least one third adjustment branch connected in parallel with the third transconductance transistor; the third adjustment branch includes a switch tube and a switch connected in series with the switch tube; wherein the gate of the switch tube is connected to the gate of the third transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate and drain of the third transconductance transistor; the current adjustment array of the fourth transconductance transistor includes at least one fourth adjustment branch connected in parallel with the fourth transconductance transistor; the fourth adjustment branch includes a switch tube and a switch connected in series with the switch tube; wherein the gate of the switch tube is connected to the gate of the fourth transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate and drain of the fourth transconductance transistor.

[0011] In combination with the first possible implementation of the first aspect, an embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein the above-mentioned first local oscillator input unit includes a first input switch tube corresponding to the first transconductance transistor, and a second input switch tube corresponding to the second transconductance transistor; wherein the source of the switch tube included in the first input switch tube is connected to the drain of the first transconductance transistor, and the source of the switch tube included in the second input switch tube is connected to the drain of the second transconductance transistor; the gates of the first input switch tube and the second input switch tube are used to input the I-way signal of the local oscillator signal; the drains of the first input switch tube and the second input switch tube are used to connect to the load stage.

[0012] In combination with the fifth 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 first input switch tube includes a first switch tube and a second switch tube, and the second input switch tube includes a third switch tube and a fourth switch tube; wherein 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 second transconductance transistor; the gates of the second switch tube and the third switch tube are connected to input the N-end signal of the I-way signal of the local oscillator 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 of the local oscillator signal; wherein the drains of the first switch tube and the third switch tube are merged and connected to the load stage; the drains of the second switch tube and the fourth switch tube are merged and connected to the load stage.

[0013] In combination with the third 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 second local oscillator input unit includes a third input switch tube corresponding to the third transconductance transistor, and a fourth input switch tube corresponding to the fourth transconductance transistor; wherein the source of the switch tube included in the third input switch tube is connected to the drain of the third transconductance transistor, and the source of the switch tube included in the fourth input switch tube is connected to the drain of the fourth transconductance transistor; the gates of the third input switch tube and the fourth input switch tube are used to input the Q signal of the local oscillator signal; the drains of the third input switch tube and the fourth input switch tube are used to connect to the load stage.

[0014] In combination with the seventh 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 third input switch tube includes a fifth switch tube and a sixth switch tube, and the fourth input switch tube includes a seventh switch tube and an eighth switch tube; wherein the source of the fifth switch tube and the sixth switch tube is connected to the drain of the third transconductance transistor; the source of the seventh switch tube and the eighth switch tube is connected to the drain of the fourth transconductance transistor; the gate of the sixth switch tube and the seventh switch tube is connected to input the N-end signal of the Q-path signal of the local oscillator 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 of the local oscillator signal; wherein the drain of the fifth switch tube and the seventh switch tube is merged and connected to the load stage; the drain of the sixth switch tube and the eighth switch tube is merged and connected to the load stage.

[0015] In a second aspect, an embodiment of the present invention further provides a mixer, wherein the mixer is equipped with the mixer correction circuit described in the first aspect.

[0016] The embodiments of the present invention bring the following beneficial effects:

[0017] A mixer correction circuit and a mixer provided by an embodiment of the present invention include a first input transconductance unit and a second input transconductance unit at an intermediate frequency input stage, which are respectively used to input an intermediate frequency I-path signal and an intermediate frequency Q-path signal, and transconductance transistors included in the first input transconductance unit and the second input transconductance unit are respectively configured with a current adjustment array, and the current adjustment array is used to suppress the current deviation of the first input transconductance unit and the second input transconductance unit to achieve current balance of the transconductance transistors of the mixer, thereby effectively reducing the leakage of the local oscillator signal to the intermediate frequency end and the radio frequency end, and the current adjustment array has a simple structure, flexible adjustment, and is insensitive to the influence of process and temperature, thereby meeting the use requirements of the mixer without affecting the performance of the mixer.

[0018] 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.

[0019] 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

[0020] 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.

[0021] Figure 1 A structural block diagram of a mixer correction circuit provided by an embodiment of the present invention;

[0022] Figure 2 A circuit diagram of an intermediate frequency input stage provided by an embodiment of the present invention;

[0023] Figure 3 A circuit diagram of a current adjustment array provided by an embodiment of the present invention;

[0024] Figure 4 A circuit diagram of another current adjustment array provided by an embodiment of the present invention;

[0025] Figure 5 A circuit diagram of a mixer correction circuit provided by an embodiment of the present invention;

[0026] Figure 6 A schematic diagram of a leakage variation curve of a local oscillator signal provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] 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.

[0028] At present, in the mixer, the method of suppressing the leakage of the local oscillator signal from the input to the output is mainly to use a notch filter or a band-stop filter to weaken the signal at the local oscillator frequency, thereby reducing the impact of its leakage to the output. Although this method has a certain inhibitory effect on the leakage of the local oscillator signal, the design of this filter is greatly affected by the device process level, and the design is difficult and costly. At the same time, when the local oscillator signal and the output RF signal are close, the leakage signal of the local oscillator signal cannot be effectively filtered out.

[0029] Based on this, a mixer correction circuit and a mixer provided in an embodiment of the present invention can effectively alleviate the above technical problems.

[0030] To facilitate understanding of this embodiment, a mixer correction circuit disclosed in an embodiment of the present invention is first introduced in detail.

[0031] In a possible implementation manner, an embodiment of the present invention provides a mixer correction circuit, such as Figure 1 The structural block diagram of a mixer correction circuit shown includes: an intermediate frequency input stage 10, a local oscillator input stage 20 and a load stage 30 connected in sequence.

[0032] Among them, the intermediate frequency input stage is used to input the intermediate frequency signal, and the intermediate frequency signal usually refers to the RF output signal output by the previous stage, such as the RF output signal after mixing output by the mixer of the previous stage, etc. The intermediate frequency signal is converted into a current signal by the intermediate frequency input stage 10 and then input to the local oscillator input stage, and is further mixed with the local oscillator signal input by the local oscillator input stage, and then the mixed RF signal is output through the load stage.

[0033] Specifically, the intermediate frequency input stage in the embodiment of the present invention includes a first input transconductance unit 101 and a second input transconductance unit 102; the first input transconductance unit 101 is used to input the intermediate frequency I-path signal, and the second input transconductance unit 102 is used to input the intermediate frequency Q-path signal; wherein the intermediate frequency I-path signal and the intermediate frequency Q-path signal respectively represent the I-path signal and the Q-path signal of the input intermediate frequency signal.

[0034] The local oscillator input stage 20 is used to input a local oscillator signal, wherein the local oscillator input stage 20 includes a first local oscillator input unit 201 and a second local oscillator input unit 202; the first local oscillator input unit 201 is connected to the first input transconductance unit 101, and the second local oscillator input unit 202 is connected to the second input transconductance unit 102; the load stage 30 includes a radio frequency output terminal for outputting a radio frequency signal.

[0035] The transconductance transistors included in the first input transconductance unit 101 and the second input transconductance unit 102 in the embodiment of the present invention are respectively configured with a current adjustment array 100 ; the current adjustment array 100 is used to suppress the current deviation of the first input transconductance unit 101 and the second input transconductance unit 102 .

[0036] A mixer correction circuit provided by an embodiment of the present invention comprises a first input transconductance unit and a second input transconductance unit at an intermediate frequency input stage, which are respectively used to input an intermediate frequency I-path signal and an intermediate frequency Q-path signal, and transconductance transistors included in the first input transconductance unit and the second input transconductance unit are respectively configured with a current adjustment array, and the current adjustment array is used to suppress the current deviation of the first input transconductance unit and the second input transconductance unit to achieve current balance of the transconductance transistors of the mixer, thereby effectively reducing the leakage of the local oscillator signal to the intermediate frequency end and the radio frequency end, and the current adjustment array has a simple structure, flexible adjustment, and is insensitive to the influence of process and temperature, thereby meeting the use requirements of the mixer without affecting the performance of the mixer.

[0037] In actual use, the transconductance transistors included in the first input transconductance unit 101 and the second input transconductance unit 102 are also called GM transistors, which can usually be implemented by MOS transistors, and the transconductance transistors in the embodiment of the present invention are also called input transistors.

[0038] For ease of understanding, Figure 1 On the basis of Figure 2 A circuit diagram of an intermediate frequency input stage is also shown.

[0039] Specifically, Figure 2As shown, the transconductance transistors included in the first input transconductance unit include a first transconductance transistor M1 and a second transconductance transistor M2; wherein the sources of the first transconductance transistor M1 and the second transconductance transistor M2 are grounded; the gate of the first transconductance transistor M1 is used to input the P-end signal of the intermediate frequency I signal, that is, Figure 2 In the example, the signal corresponding to IF_IP, the gate of the second transconductance transistor M2 is used to input the N-terminal signal of the intermediate frequency I signal, that is, Figure 2 , the signal corresponding to IF_IN.

[0040] The drain of the first transconductance transistor M1 and the drain of the second transconductance transistor M2 are respectively connected to the first local oscillator input unit, that is, corresponding to Figure 2 Point A and point B in.

[0041] further, Figure 2 In FIG. 1 , the transconductance transistor included in the second input transconductance unit is also shown, that is, Figure 2 The third transconductance transistor M3 and the fourth transconductance transistor M4 in.

[0042] The sources of the third transconductance transistor M3 and the fourth transconductance transistor M4 are grounded; the gate of the third transconductance transistor M3 is used to input the P-end signal of the intermediate frequency Q-path signal, that is, Figure 2 In the example, the signal corresponding to IF_QP, the gate of the fourth transconductance transistor M4 is used to input the N-terminal signal of the intermediate frequency Q-path signal, that is, Figure 2 In the figure, the signal corresponding to IF_QN;

[0043] The drain of the third transconductance transistor M3 and the drain of the fourth transconductance transistor M4 are respectively connected to the second local oscillator input unit, that is, corresponding to Figure 2 Points C and D in.

[0044] Furthermore, the current adjustment array in the embodiment of the present invention includes at least one first adjustment branch connected in parallel with the transconductance transistor, that is, the first transconductance transistor M1, the second transconductance transistor M2, the third transconductance transistor M3 and the fourth transconductance transistor M4 have corresponding current adjustment arrays respectively.

[0045] Specifically, for ease of understanding, Figure 2 On the basis of Figure 3 A circuit diagram of a current adjustment array is also shown. And, Figure 4 A circuit diagram of another current adjustment array is shown.

[0046] in, Figure 3 The figure shows a current adjustment array corresponding to the first transconductance transistor and the second transconductance transistor in the first input transconductance unit. Figure 4Shown is a current adjustment array corresponding to the third transconductance transistor and the fourth transconductance transistor in the second input transconductance unit.

[0047] Specifically, Figure 3 , M1_1 represents the first transconductance transistor M1, and the current adjustment array of the first transconductance transistor includes at least one first adjustment branch connected in parallel with the first transconductance transistor; the first adjustment branch includes a switch tube, and a switch connected in series with the switch tube; wherein, in the current adjustment array of the first transconductance transistor, the gate of the switch tube is connected to the gate of the first transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate-drain of the first transconductance transistor;

[0048] Similarly, M2_1 represents the above-mentioned second transconductance transistor M2, and the current adjustment array of the second transconductance transistor includes at least one second adjustment branch connected in parallel with the second transconductance transistor; the second adjustment branch includes a switch tube, and a switch connected in series with the switch tube; and, in the second adjustment branch, the gate of the switch tube is connected to the gate of the second transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate-drain of the second transconductance transistor.

[0049] Further, with Figure 3 Similar structures in Figure 4 In the figure, M3_1 represents the third transconductance transistor M3, and the current adjustment array of the third transconductance transistor includes at least one third adjustment branch connected in parallel with the third transconductance transistor; the third adjustment branch includes a switch tube, and a switch connected in series with the switch tube;

[0050] Wherein, in the third adjustment branch, the gate of the switch tube is connected to the gate of the third transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate-drain of the third transconductance transistor;

[0051] Similarly, M4_1 represents the fourth transconductance transistor M4, and the current adjustment array of the fourth transconductance transistor includes at least one fourth adjustment branch connected in parallel with the fourth transconductance transistor; the fourth adjustment branch includes a switch tube, and a switch connected in series with the switch tube; and, in the fourth adjustment branch, the gate of the switch tube is connected to the gate of the fourth transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate-drain of the fourth transconductance transistor.

[0052] in, Figure 3 and Figure 4 In the present invention, the transconductance transistor is directly designed into a current adjustment array, also known as a trim current array, and, Figure 3The trim array of transconductance transistors M1 and M2 for the intermediate frequency I signal, Figure 4 The trim array of transconductance transistors M3 and M4 for the intermediate frequency Q-path signal.

[0053] and, Figure 3 and Figure 4 In the embodiments, the current adjustment array includes three adjustment branches, that is, a 3-bit array. In actual use, more bit arrays can be made according to needs, that is, the number of adjustment branches can be set according to actual usage, and the embodiments of the present invention do not limit this.

[0054] further, Figure 3 In the example, the current adjustment arrays of M1 and M2 have a fixed branch M1_1 and M2_1 respectively, and three adjustment branches M1_2 to M1_4 and M2_2 to M2_4 respectively. The adjustment branches are controlled by reverse switch control signals, i.e., switches S1 to S3 and switches S4 to S6, so as to achieve adjustable static currents of the transconductance transistors M1 and M2 of the intermediate frequency I signal. Similarly, Figure 4 The current trim array of transconductance transistors M3 and M4, with Figure 3 Moreover, the circuit structure of the switch tube of the adjustment branch in the embodiment of the present invention is similar to the current mirror junction, which is insensitive to temperature and can realize the correction of the circuit static current as long as it has a certain monotonicity.

[0055] Furthermore, in the local oscillator input stage of the embodiment of the present invention, the first local oscillator input unit includes a first input switch tube corresponding to the first transconductance transistor, and a second input switch tube corresponding to the second transconductance transistor; wherein the source of the switch tube included in the first input switch tube is connected to the drain of the first transconductance transistor, and the source of the switch tube included in the second input switch tube is connected to the drain of the second transconductance transistor; the gates of the first input switch tube and the second input switch tube are used to input the I-way signal of the local oscillator signal; the drains of the first input switch tube and the second input switch tube are used to connect to the load stage.

[0056] Furthermore, the second local oscillator input unit includes a third input switch tube corresponding to the third transconductance transistor, and a fourth input switch tube corresponding to the fourth transconductance transistor; wherein the source of the switch tube included in the third input switch tube is connected to the drain of the third transconductance transistor, and the source of the switch tube included in the fourth input switch tube is connected to the drain of the fourth transconductance transistor; the gates of the third input switch tube and the fourth input switch tube are used to input the Q-path signal of the local oscillator signal; the drains of the third input switch tube and the fourth input switch tube are used to be connected to the load stage.

[0057] For ease of understanding, Figure 1 On the basis of Figure 5 A circuit diagram of a mixer correction circuit is shown, and Figure 5 In FIG. 5 , the first input transconductance unit 101 , the second input transconductance unit 102 , the first local oscillator input unit 201 , the second local oscillator input unit 202 and the load stage 30 are shown in dashed boxes.

[0058] Specifically, Figure 5 As shown, in the first local oscillator input unit 201 , the first input switch tube includes a first switch tube M5 and a second switch tube M6 , and the second input switch tube includes a third switch tube M7 and a fourth switch tube M8 .

[0059] Among them, the source of the first switch tube M5 and the second switch tube M6 is connected to the drain of the first transconductance transistor M1, that is, Figure 5 The source of the third switch tube M7 and the fourth switch tube M8 is connected to the drain of the second transconductance transistor M2, that is, Figure 5 Connect point B in .

[0060] Specific as Figure 5 As shown, the gates of the second switch tube M6 and the third switch tube M7 are connected to input the N-end signal of the I-channel signal of the above-mentioned local oscillation signal, that is, Figure 5 In the example, corresponding to the signal corresponding to LO_IN, the gates of the first switch tube M5 and the fourth switch tube M8 are used to input the P-end signal of the I-channel signal of the local oscillator signal, that is, Figure 5 , the signal corresponding to LO_IP.

[0061] The drains of the first switch tube M5 and the third switch tube M7 are combined and connected to the load stage; the drains of the second switch tube M6 and the fourth switch tube M8 are combined and connected to the load stage.

[0062] Further, similar to the structure of the first local oscillator input unit, as Figure 5 As shown, the third input switch tube of the second local oscillator input unit includes a fifth switch tube M9 and a sixth switch tube M10, and the fourth input switch tube includes a seventh switch tube M11 and an eighth switch tube M12.

[0063] Among them, the source of the fifth switch tube M9 and the sixth switch tube M10 and the drain of the third transconductance transistor M3, that is, Figure 5 The source of the seventh switch tube M11 and the eighth switch tube M12 is connected to the drain of the fourth transconductance transistor M4, that is, Figure 5 Connect point D in .

[0064] Specifically, the gates of the sixth switch tube M10 and the seventh switch tube M11 are connected to input the N-end signal of the Q-path signal of the local oscillation signal, that is, Figure 5The gate of the fifth switch tube M9 and the eighth switch tube M12 is used to input the P-end signal of the Q-path signal of the local oscillator signal, that is, Figure 5 , the signal corresponding to LO_QP.

[0065] The drains of the fifth switch tube M9 and the seventh switch tube M11 are combined and connected to the load stage; the drains of the sixth switch tube M10 and the eighth switch tube M12 are combined and connected to the load stage.

[0066] further, Figure 5 In the figure, the load stage includes the RF output terminals VOP and VON of the mixer, and an output load circuit. Specifically, the output load circuit includes capacitors C1, C2 and a tapped differential inductor L1, and the tap of L1 is connected to VDD. In addition, the capacitors C1, C2 and the inductor L1 form an LC oscillation load, also called an LC tank, which serves as the output load of the mixer.

[0067] The following is based on Figure 5 The mixer correction circuit shown, and Figure 2 to Figure 4 The circuit diagram of the intermediate frequency input stage shown in FIG. 1 is used to explain in detail the working principle of the mixer correction circuit provided in the embodiment of the present invention:

[0068] based on Figure 5 The mixer correction circuit shown in the figure includes the following parts: the first transconductance transistor M1 and the second transconductance transistor M2 are used as transconductance transistors of the intermediate frequency input stage I path, i.e., GM tubes; the third transconductance transistor M3 and the fourth transconductance transistor M4 are used as GM tubes of the intermediate frequency input stage Q path; M5-M8 are used as switch tubes of the first local oscillator input unit in the local oscillator output stage, used to input the I path signal of the local oscillator signal LO; M9-M12 are used as switch tubes of the second local oscillator input unit in the local oscillator output stage, used to input the Q path signal of the local oscillator signal LO; the parameters of M1-M4 are exactly the same, and the parameters of M5-M12 are exactly the same. Capacitors C1, C2 and inductor L1 form the output load of the mixer.

[0069] Further, IF_IP is the P-end input of the I-channel of the intermediate frequency signal, corresponding to the P-end signal of the I-channel signal of the intermediate frequency; IF_IN is the N-end input of the I-channel of the intermediate frequency signal, corresponding to the N-end signal of the I-channel signal of the intermediate frequency; IF_QP is the P-end input of the Q-channel of the intermediate frequency signal, corresponding to the P-end signal of the Q-channel signal of the intermediate frequency; IF_QN is the N-end input of the Q-channel of the intermediate frequency signal, corresponding to the N-end signal of the Q-channel signal of the intermediate frequency; similarly, LO_IP is the P-end input of the I-channel of the local oscillator signal, corresponding to the P-end signal of the I-channel signal of the local oscillator signal; LO_IN is the N-end input of the I-channel of the local oscillator signal, corresponding to the N-end signal of the I-channel signal of the local oscillator signal; LO_QP is the P-end input of the Q-channel of the local oscillator signal, corresponding to the P-end signal of the Q-channel signal of the local oscillator signal; LO_QN is the N-end input of the Q-channel of the local oscillator signal, corresponding to the N-end signal of the Q-channel signal of the local oscillator signal; VOP and VON serve as the RF output ends of the mixer.

[0070] and, Figure 5 In the embodiment, the first transconductance transistor M1 is used as the input tube of the P-end signal of the intermediate frequency I-channel signal, and is connected to the switch tubes M5 and M6 of the I-channel input P-end and N-end of the local oscillator signal; the second transconductance transistor M2 is used as the input tube of the P-end signal of the intermediate frequency I-channel signal, and is connected to the switch tubes M7 and M8 of the I-channel input P-end and N-end of the local oscillator signal; because the drain ends (drains) of M5 and M7 in the embodiment of the present invention are combined and connected to the output end VOP, the drain ends (drains) of M6 and M8 are combined and connected to the output end VON. The structure of the intermediate frequency I-channel signal is similar, that is, the intermediate frequency signals divided into I-channel and Q-channel are input from M1 to M4, and then converted into current signals, which are respectively sent to the input tubes of the local oscillator signal LO composed of M5 to M12, and after mixing with the local oscillator signal, a higher RF signal is generated and sent to the output end.

[0071] In actual use, the local oscillator signal LO is a high-frequency and high-power signal, which will leak to the RF output end of the load stage through the parasitic capacitance Cgd of the gate-drain of the MOS tubes M5 to M12, and will also leak to the intermediate frequency input end of the intermediate frequency input stage through Cgs. However, the frequencies of the intermediate frequency signal and the local oscillator signal LO are far apart, and will be filtered out by a filter or a pre-stage circuit, while the local oscillator signal LO and the RF signal output by the load stage are high-frequency signals that are close to each other, so the local oscillator signal leaking to the RF output end of the load stage will cause greater interference to the useful signal.

[0072] Ideally, based on Figure 5 In the structure shown, input tubes M1 to M4 are biased by the same DC bias voltage, and the static current flowing through them is the same. Then M5 to M12 are also biased by the same DC bias voltage, and the current flowing through them is also the same.

[0073] For example, the intermediate frequency voltage signal of the intermediate frequency signal I is input from M1 and M2, and then converted into a current signal, and sent to the switch tubes of the local oscillator signal I of M5 and M6 and M7 and M8 respectively, and mixed with the local oscillator signal.

[0074] In this process, the P-end signal of the I-path of the local oscillator signal LO will leak to its output end through M5 and M8, and the N-end signal of the I-path of the local oscillator signal LO will leak to its output end through M6 and M7. Because the output ends of M5 and M7 are connected, the signals leaked to their output ends will cancel each other out due to their opposite polarities, thereby suppressing the leakage of the local oscillator signal LO. Similarly, the Q-path signal of the local oscillator signal LO is also the same.

[0075] Therefore, based on Figure 5 The mixer correction circuit can suppress the leakage of the local oscillator signal LO to a certain extent.

[0076] However, in actual application, due to process errors and layout factors, the static currents flowing through transistors M1 to M4 are not the same. If the static currents flowing through the transconductance transistors M1 and M2 of the intermediate frequency signal I path are unbalanced, that is, the transconductances of M1 and M2 are not equal, then the corresponding currents flowing through M5 and M6, and M7 and M8 are also not equal. This DC current deviation will cause differences in the voltages at the terminals of the MOS tubes M5 and M6, and M7 and M8. The parasitic capacitances seen through the ports of MOS tubes M5 and M6 are different from those of M7 and M8, and the frequency conversion gains of the MOS tubes are not the same, which results in the local oscillator signals leaking from M5 and M6 to the output end being different from those of M7 and M8. Therefore, the leakage of the local oscillator signals of M5 and M7 and the leakage of the local oscillator signals of M6 and M8 cannot offset each other, resulting in the deterioration of the leakage of the local oscillator signals. The static current imbalance of the intermediate frequency signal Q path will also lead to the same phenomenon.

[0077] In the embodiment of the present invention, a current adjustment array is further configured in each transconductance transistor, that is, Figure 3 and Figure 4 The schematic diagram shown can further alleviate the phenomenon of leakage deterioration of the local oscillator signal.

[0078] Specifically, Figure 3 The current adjustment array corresponding to the first transconductance transistor M1 and the second transconductance transistor M2 of the first input transconductance unit is taken as an example for explanation.

[0079] In the transconductance transistors of the intermediate frequency signal I path, M1_1~M1_4 are used together as transconductance transistors, the gate ends of M1_1~M1_4 are connected together, connected to the P-end input IF_IP of the intermediate frequency signal I path, the drain ends are connected together and connected to the source ends (point A) of M5 and M6, and a switch is connected in series at the source ends of M1_2~M1_4 respectively, that is, S1~S3, and then the combined circuit is connected to the source end of M1_1 and then connected to the ground.

[0080] Similarly, M2_1 to M2_4 act as transconductance transistors together, the gate ends of M2_1 to M2_4 are connected together to the N-end input IF_IN of the I path of the intermediate frequency signal, the drain ends are connected together to the source ends (point B) of M7 and M8, a switch is connected in series at the source ends of M2_2 to M2_4 respectively, and then the combined circuit is connected to the source end of M2_1 and then connected to the ground.

[0081] The working principle is as follows: Due to the influence of process errors, layout effects, temperature factors and other factors, the currents I1 and I2 flowing through M1_1 and M2_1 in the transconductance transistor of the intermediate frequency signal I are not equal, and there is a certain imbalance. The adjustment branches of M1_2 to M1_4 and the on-off of the adjustment branches of M2_2 to M2_4 can be controlled by switches, so that the current of the P-terminal path of the intermediate frequency I signal (the current from point A to the ground) of the transconductance transistor is equal to the current of the N-terminal path of the intermediate frequency I signal (the current from point B to the ground). Because the trim (drain) current of the P-end path of the intermediate frequency I-channel signal and the N-end path of the intermediate frequency I-channel signal have opposite change trends, the current of the P-end path of the intermediate frequency I-channel signal increases monotonically with the current trim codeword, while the current of the N-end path of the intermediate frequency I-channel signal decreases monotonically with the current trim codeword (the opposite design can also be made without affecting the circuit function). Therefore, within the adjustable range, a codeword will inevitably be found to make the currents of the P-end and N-end paths of the intermediate frequency I-channel signal equal.

[0082] Example: if Figure 3 In the equation, I1>I2, and I1-I2=3*△I, corresponding to Figure 3 In the figure, the current change adjusted by S1 and S4 is △I, the current change adjusted by S2 and S5 is 2△I, and the current change adjusted by S3 and S6 is 4△I;

[0083] Then, the current of the P-terminal path of the intermediate frequency I-channel signal can be reduced by controlling the switch, and the current of the N-terminal path of the intermediate frequency I-channel signal can be increased, that is, the switch control code is set to code=2 (binary is b010, that is, i_ctl <1> is high level, i_ctl <0> and i_ctl <2> is low level), that is, switch S2 is on, S1 and S3 are off, so the current of the P-end path of the intermediate frequency I signal is the sum of the current flowing through M1_1 and the current flowing through M1_3, so the current of the P-end path of the intermediate frequency I signal is expressed as: I1+2*△I;

[0084] The control switches of the N-end path of the intermediate frequency I signal are just opposite to those of the P-end path of the intermediate frequency I signal, that is, switches S4 and S6 are on, and S5 is off, so the current of the N-end path of the intermediate frequency I signal is the sum of the current flowing through M2_1 and the current flowing through M2_2 and M2_4, so the current of the N-end path of the intermediate frequency I signal is I1+5*△I.

[0085] Because it is known that I1-I2=3*△I, the current flowing through the P-end path of the intermediate frequency I signal and the N-end path of the intermediate frequency I signal are equal, that is, the current flowing through M5~M8 is also the same, so the local oscillator leakage signal can cancel each other out at the output end. The final output local oscillator signal leakage signal (LOL) and code word change curve are as follows: Figure 6 shown.

[0086] in, Figure 6 In the figure, the horizontal axis represents the codeword code, and the vertical axis represents the current (I / mA), wherein the IP path represents the current of the P-end path of the intermediate frequency I-path signal, and the IN path represents the current of the N-end path of the intermediate frequency I-path signal. The dotted line represents the leakage signal of the local oscillator signal, which is represented by LOL and the unit is dBm. The dotted line represents the change of the leakage signal of the local oscillator signal. Figure 6 It can be seen that the leakage signal of the local oscillator signal is effectively alleviated under the adjustment of the current adjustment array.

[0087] Figure 4 The current adjustment array corresponding to the third transconductance transistor M3 and the fourth transconductance transistor M4 of the second input transconductance unit shown corresponds to the Q path of the intermediate frequency signal, and its working principle is the same as that of the I path, which will not be repeated here.

[0088] Therefore, the circuit structure of the current adjustment array of the mixer correction circuit provided in the embodiment of the present invention can achieve an adjustment range of 0 to 7*△I, and an adjustment current accuracy of △I. In addition, in combination with different circuit requirements, a circuit structure with more bits can be designed to achieve a wider range and higher precision adjustment.

[0089] In summary, compared with the prior art, the mixer correction circuit provided in the embodiment of the present invention can correct the deviation of the static current of the mixer P and N terminals caused by the process, layout and temperature through simple current trim, thereby effectively suppressing the leakage of the local oscillator signal, and thus can meet the suppression degree of the local oscillator signal in different scenarios. In addition, the adjustment method of the above circuit can be flexible and practical, and can realize multi-bit, high-precision control, and has low power consumption and high stability.

[0090] Furthermore, an embodiment of the present invention also provides a mixer, wherein the mixer is provided with the above mixer correction circuit.

[0091] The mixer provided in the embodiment of the present invention has the same technical features as the mixer correction circuit 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 system and device described above can refer to the corresponding process in the aforementioned method 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 mixer correction circuit, characterized in that: include: The intermediate frequency input stage, the local oscillator input stage and the load stage are connected in sequence; The intermediate frequency input stage includes a first input transconductance unit and a second input transconductance unit; The first input transconductance unit is used to input an intermediate frequency I-path signal, and the second input transconductance unit is used to input an intermediate frequency Q-path signal; The local oscillator input stage is used to input a local oscillator signal, wherein the local oscillator input stage includes a first local oscillator input unit and a second local oscillator input unit; the first local oscillator input unit is connected to the first input transconductance unit, and the second local oscillator input unit is connected to the second input transconductance unit; The load stage includes a radio frequency output terminal for outputting a radio frequency signal; Wherein, the transconductance transistors included in the first input transconductance unit and the second input transconductance unit are respectively configured with a current adjustment array; The current adjustment array is used to suppress current deviation of the first input transconductance unit and the second input transconductance unit.

2. The mixer correction circuit according to claim 1, characterized in that: The transconductance transistors included in the first input transconductance unit include a first transconductance transistor and a second transconductance transistor; Wherein, the sources of the first transconductance transistor and the second transconductance transistor are grounded; The gate of the first transconductance transistor is used to input a P-terminal signal of an intermediate frequency I-channel signal, and the gate of the second transconductance transistor is used to input an N-terminal signal of an intermediate frequency I-channel signal; A drain of the first transconductance transistor and a drain of the second transconductance transistor are respectively connected to the first local oscillator input unit.

3. The mixer correction circuit according to claim 2, characterized in that: The current adjustment array of the first transconductance transistor comprises at least one first adjustment branch connected in parallel with the first transconductance transistor; The first adjustment branch includes a switch tube, and a switch connected in series with the switch tube; The gate of the switch tube is connected to the gate of the first transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate and drain of the first transconductance transistor; The current adjustment array of the second transconductance transistor comprises at least one second adjustment branch connected in parallel with the second transconductance transistor; The second adjustment branch includes a switch tube, and a switch connected in series with the switch tube; The gate of the switch tube is connected to the gate of the second transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate-drain of the second transconductance transistor.

4. The mixer correction circuit according to claim 1, characterized in that: The transconductance transistors included in the second input transconductance unit include a third transconductance transistor and a fourth transconductance transistor; Wherein, the sources of the third transconductance transistor and the fourth transconductance transistor are grounded; The gate of the third transconductance transistor is used to input the P-terminal signal of the intermediate frequency Q-path signal, and the gate of the fourth transconductance transistor is used to input the N-terminal signal of the intermediate frequency Q-path signal; A drain of the third transconductance transistor and a drain of the fourth transconductance transistor are respectively connected to the second local oscillator input unit.

5. The mixer correction circuit according to claim 4, characterized in that: The current adjustment array of the third transconductance transistor comprises at least one third adjustment branch connected in parallel with the third transconductance transistor; The third adjustment branch includes a switch tube, and a switch connected in series with the switch tube; The gate of the switch tube is connected to the gate of the third transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate-drain of the third transconductance transistor; The current adjustment array of the fourth transconductance transistor includes at least one fourth adjustment branch connected in parallel with the fourth transconductance transistor; the fourth adjustment branch includes a switch tube, and a switch connected in series with the switch tube; Among them, the gate of the switch tube is connected to the gate of the fourth transconductance transistor, the source of the switch tube is connected to one end of the switch, and the other end of the switch is grounded; the drain of the switch tube is connected to the gate and drain of the fourth transconductance transistor.

6. The mixer correction circuit according to claim 2, characterized in that: The first local oscillator input unit includes a first input switch tube corresponding to the first transconductance transistor, and a second input switch tube corresponding to the second transconductance transistor; The source of the switch tube included in the first input switch tube is connected to the drain of the first transconductance transistor, and the source of the switch tube included in the second input switch tube is connected to the drain of the second transconductance transistor; The gates of the first input switch tube and the second input switch tube are used to input an I-channel signal of the local oscillator signal; The drains of the first input switch tube and the second input switch tube are used to be connected to the load stage.

7. The mixer correction circuit according to claim 6, characterized in that: The first input switch tube includes a first switch tube and a second switch tube, and the second input switch tube includes a third switch tube and a fourth switch tube; Wherein, 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 second transconductance transistor; The gates of the second switch tube and the third switch tube are connected to input the N-end signal of the I-channel signal of the local oscillator signal; the gates of the first switch tube and the fourth switch tube are used to input the P-end signal of the I-channel signal of the local oscillator signal; The drains of the first switch tube and the third switch tube are combined and connected to the load stage; the drains of the second switch tube and the fourth switch tube are combined and connected to the load stage.

8. The mixer correction circuit according to claim 4, characterized in that: The second local oscillator input unit includes a third input switch tube corresponding to the third transconductance transistor, and a fourth input switch tube corresponding to the fourth transconductance transistor; The source of the switch tube included in the third input switch tube is connected to the drain of the third transconductance transistor, and the source of the switch tube included in the fourth input switch tube is connected to the drain of the fourth transconductance transistor; The gates of the third input switch tube and the fourth input switch tube are used to input the Q-path signal of the local oscillator signal; The drains of the third input switch tube and the fourth input switch tube are used to be connected to the load stage.

9. The mixer correction circuit according to claim 8, characterized in that: The third input switch tube includes a fifth switch tube and a sixth switch tube, and the fourth input switch tube includes a seventh switch tube and an eighth switch tube; Wherein, the source electrodes of the fifth switch tube and the sixth switch tube are connected to the drain electrode of the third transconductance transistor; the source electrodes of the seventh switch tube and the eighth switch tube are connected to the drain electrode of the fourth transconductance transistor; The gates of the sixth switch tube and the seventh switch tube are connected to input the N-end signal of the Q-path signal of the local oscillator 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 of the local oscillator signal; The drains of the fifth switch tube and the seventh switch tube are combined and connected to the load stage; the drains of the sixth switch tube and the eighth switch tube are combined and connected to the load stage.

10. A mixer, characterized in that: The mixer is provided with the mixer correction circuit according to any one of claims 1 to 9.

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