Low noise amplifier, radio frequency receiver and electronic device

Abstract

The embodiment of the invention provides a low noise amplifier, a radio frequency receiver and an electronic device, the amplifier is of a differential input and output structure, the amplifier comprises a first main amplifier (110), a second main amplifier (120), a first feedback amplifier (130) and a second feedback amplifier (140), the first main amplifier (110) and the second main amplifier (120) are the same in structure, and the first feedback amplifier (130) and the second feedback amplifier (140) are different in structure. The first feedback amplifier (130) and the second feedback amplifier (140) have the same structure, and the first main amplifier (110), the second main amplifier (120), the first feedback amplifier (130) and the second feedback amplifier (140) are all inverting amplifiers. According to the broadband low-noise amplifier, the problem that an amplifier which is wide in working frequency, high in linearity and low in noise coefficient is difficult to achieve in the prior art can be solved, the main amplifier and the feedback amplifier are connected through the differential input and output structure, and the linearity of the broadband low-noise amplifier is improved.

Description

Technical Field

[0001] The present application relates to the field of electronic circuits, and in particular to a low noise amplifier, a radio frequency receiver and an electronic device. Background Art

[0002] With the development of wireless communications, various application scenarios have put forward higher and higher demands on the bandwidth of communication systems. In order to meet the needs of high communication rates and multi-standard support, high-performance transceivers suitable for large bandwidth scenarios have become one of the focuses of wireless communication technology research. Compared with narrowband communication systems, large-bandwidth systems not only face more complex external interference due to the wider frequency band used, but are also more susceptible to interference caused by their own nonlinearity, resulting in poor noise performance of the system. As the first stage in most receiver links, low-noise amplifiers not only need to achieve a low noise figure, but also need to maintain high linearity over a larger bandwidth to suppress interference and maintain receiver sensitivity.

[0003] Traditional broadband low-noise amplifiers often use a common-gate input structure to achieve a large bandwidth of the amplifier. However, the transconductance of the input tube of the common-gate structure is constrained by the input impedance matching, and generally needs to be maintained at around 20mS, so the gain of the amplifier is structurally limited. In comparison, the common-source amplifier can achieve a larger voltage gain. A single common-source amplifier often uses source negative feedback to improve linearity, and reduces the change of the gate-source voltage when the MOS tube is working by adding a degenerate resistor to the source, thereby reducing the nonlinearity of the amplifier. However, due to the thermal noise of the resistor, the introduction of the source degenerate resistor will deteriorate the noise factor of the amplifier. In order to reduce the deterioration of the noise factor, an inductor-source degenerate structure can be used. However, the impedance of the inductor is affected by the operating frequency, and the resonance range is small. The inductor-source degenerate structure has a good effect only in narrow-band amplifiers. Therefore, how to achieve an amplifier with a wide operating frequency, high linearity, and low noise factor is still a difficult problem.

[0004] In summary, there is no good solution to the problem in the related art that it is difficult to realize an amplifier with a wide operating frequency, high linearity and low noise figure. Summary of the invention

[0005] The embodiments of the present application provide a low noise amplifier, a radio frequency receiver and an electronic device to at least solve the problem in the related art that it is difficult to realize an amplifier with a wide operating frequency, high linearity and low noise coefficient.

[0006] According to an embodiment of the present application, a low noise amplifier is provided, the low noise amplifier comprising: a first main amplifier (110), a second main amplifier (120), a first feedback amplifier (130) and a second feedback amplifier (140), the low noise amplifier having a first input terminal, a second input terminal, a first output terminal and a second output terminal, the first input terminal and the second input terminal being used to respectively receive a first input signal and a second input signal, the first output terminal and the second output terminal being used to respectively output a first output signal and a second output signal amplified by the low noise amplifier, wherein the first input signal and the second input signal are a pair of differential input signals, wherein:

[0007] The first main amplifier (110) and the second main amplifier (120) have the same structure, the first feedback amplifier (130) and the second feedback amplifier (140) have the same structure, and the first main amplifier (110), the second main amplifier (120), the first feedback amplifier (130) and the second feedback amplifier (140) are all inverting amplifiers;

[0008] The input end of the first main amplifier (110) is connected to the first input end of the low noise amplifier and the output end of the first feedback amplifier, the output end of the first main amplifier is connected to the input end of the second feedback amplifier and the first output end of the low noise amplifier, the first main amplifier receives a first input signal and a first feedback signal output by the first feedback amplifier and performs inverse amplification to obtain a first output signal and outputs the first output signal at the output end of the first main amplifier;

[0009] A second feedback amplifier (140) is used to amplify the first output signal from the output end of the first main amplifier to obtain a second feedback signal and output the second feedback signal at the output end of the second feedback amplifier;

[0010] The input end of the second main amplifier (120) is connected to the second input end of the low noise amplifier and the output end of the second feedback amplifier, the output end of the second main amplifier is connected to the input end of the first feedback amplifier and the second output end of the low noise amplifier, the second main amplifier receives the second input signal and the second feedback signal output by the second feedback amplifier and performs inverse amplification to obtain a second output signal and outputs the second output signal at the output end of the second main amplifier;

[0011] The first feedback amplifier (130) is used to amplify the second output signal from the output end of the second main amplifier to obtain a first feedback signal and output the first feedback signal at the output end of the first feedback amplifier.

[0012] According to yet another embodiment of the present application, a radio frequency receiver is provided, comprising the low noise amplifier in any one of the above embodiments.

[0013] According to yet another embodiment of the present application, an electronic device is provided, comprising the low noise amplifier in any one of the above embodiments.

[0014] Through the embodiments of the present application, a low-noise amplifier is designed, in which both the main amplifier and the feedback amplifier use an inverting amplifier structure, and the main amplifier and the feedback amplifier are connected using a differential input and output and a cross-feedback structure, which can not only ensure the polarity of the negative feedback, but also solve the problem in the related art that it is difficult to realize an amplifier with a wide operating frequency, high linearity and low noise factor, thereby improving the linearity of the broadband low-noise amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram of a low noise amplifier according to an embodiment of the present application;

[0016] Figure 2 is a structural block diagram of a negative feedback amplifier according to an embodiment of the present application;

[0017] Figure 3 is a connection diagram of a low noise amplifier according to an embodiment of the present application;

[0018] Figure 4 is a connection diagram of another low noise amplifier according to an embodiment of the present application;

[0019] Figure 5 is a schematic diagram of an amplifier structure based on an inverter structure according to an embodiment of the present application;

[0020] Figure 6 is a structural schematic diagram of a common source amplifier according to an embodiment of the present application (I);

[0021] Figure 7 is a structural schematic diagram of a common source amplifier according to an embodiment of the present application (II);

[0022] Figure 8 1 is a schematic diagram of the structure of an amplifier with differential input and output and cross-feedback structure according to an embodiment of the present application (I);

[0023] Fig. 9 2 is a schematic diagram of the structure of an amplifier with differential input and output and cross-feedback structure according to an embodiment of the present application (II);

[0024] Fig.10 is a schematic diagram of amplifier gain comparison according to an embodiment of the present application;

[0025] Fig.11 is a schematic diagram comparing amplifier reflection coefficients according to an embodiment of the present application;

[0026] Fig.12is a schematic diagram comparing amplifier noise coefficients according to an embodiment of the present application;

[0027] Fig.13 4 is a schematic diagram of comparing amplifier linearity according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0030] A low noise amplifier is provided in an embodiment of the present application. Figure 1 is a block diagram of a low noise amplifier according to an embodiment of the present application, such as Figure 1 As shown, the low noise amplifier includes the following structure:

[0031] A first main amplifier (110), a second main amplifier (120), a first feedback amplifier (130) and a second feedback amplifier (140).

[0032] In this embodiment, the low-noise amplifier has a first input terminal, a second input terminal, a first output terminal and a second output terminal, the first input terminal and the second input terminal are used to respectively receive a first input signal and a second input signal, the first output terminal and the second output terminal are used to respectively output a first output signal and a second output signal amplified by the low-noise amplifier, wherein the first input signal and the second input signal are a pair of differential input signals.

[0033] In this embodiment, the first main amplifier (110) and the second main amplifier (120) have the same structure, the first feedback amplifier (130) and the second feedback amplifier (140) have the same structure, and the first main amplifier (110), the second main amplifier (120), the first feedback amplifier (130) and the second feedback amplifier (140) are all inverting amplifiers.

[0034] In this embodiment, the input end of the first main amplifier (110) is connected to the first input end of the low noise amplifier and the output end of the first feedback amplifier, the output end of the first main amplifier is connected to the input end of the second feedback amplifier and the first output end of the low noise amplifier, the first main amplifier receives the first input signal and the first feedback signal output by the first feedback amplifier and performs reverse amplification to obtain a first output signal and outputs the first output signal at the output end of the first main amplifier.

[0035] In this embodiment, the second feedback amplifier (140) is used to amplify the first output signal from the output end of the first main amplifier to obtain a second feedback signal and output the second feedback signal at the output end of the second feedback amplifier.

[0036] In this embodiment, the input end of the second main amplifier (120) is connected to the second input end of the low noise amplifier and the output end of the second feedback amplifier, and the output end of the second main amplifier is connected to the input end of the first feedback amplifier and the second output end of the low noise amplifier. The second main amplifier receives the second input signal and the second feedback signal output by the second feedback amplifier and performs reverse amplification to obtain a second output signal and outputs the second output signal at the output end of the second main amplifier.

[0037] In this embodiment, the first feedback amplifier (130) is used to amplify the second output signal from the output end of the second main amplifier to obtain the first feedback signal and output the first feedback signal at the output end of the first feedback amplifier.

[0038] In the embodiment of the present application, the main amplifier and the feedback amplifier are connected by a differential input-output and cross-feedback structure, and both the main amplifier and the feedback amplifier are inverting amplifiers, which ensures the polarity of negative feedback. The negative feedback circuit adopts an inverting amplifier structure instead of a commonly used inverting amplifier structure to achieve a higher negative feedback gain, which is beneficial to improving the overall linearity of the amplifier, thereby solving the problem in the related art that it is difficult to achieve an amplifier with a wide operating frequency, high linearity and low noise coefficient.

[0039] Figure 2 1 is a block diagram of a negative feedback amplifier according to an embodiment of the present application. In combination with the negative feedback theory, the principle of improving the linearity of the amplifier according to the embodiment of the present application is specifically introduced through the following embodiments. Figure 2 As shown, the negative feedback amplifier includes the following structure:

[0040] A feed-forward amplifier 210 and a feedback amplifier 220 .

[0041] In this embodiment, the gain of the feedforward amplifier 210 is A, and the gain of the feedback amplifier 220 is β.

[0042] Assuming that the feedforward amplifier is a weakly nonlinear amplifier, the relationship between its output Y and input X can be expressed as a power series:

[0043] Y=g1X+g2X 2 +g3X 3 , where g1 is the linear gain, g2 is the second-order nonlinear coefficient, and g3 is the third-order nonlinear coefficient.

[0044] Then for Figure 2In the negative feedback structure, the relationship between output and input can be expressed as: Y = b1X + b2X 2 +b3X 3 , where b1 is the closed-loop linear gain of the negative feedback system, b2 is the second-order nonlinear coefficient of the negative feedback system, and b3 is the third-order nonlinear coefficient of the negative feedback system.

[0045] According to the negative feedback theory, b 1，23 With g 1，23 The relationship is:

[0046]

[0047]

[0048]

[0049] Among them, T0=g1β is the linear open-loop gain of the negative feedback system.

[0050] In the related art, the input second-order intermodulation intercept point I IP2 and the input third-order intermodulation intercept point I IP3 are generally used to measure the linearity of the amplifier. The higher the values ​​of I IP2 and I IP3, the better the linearity of the amplifier.

[0051] For the weak nonlinear amplifier A, the second-order and third-order intermodulation formulas of the weak nonlinear system are:

[0052]

[0053]

[0054] Among them, A IIP2 is the second-order intermodulation, A IIP3 It is third-order intermodulation.

[0055] According to the second-order and third-order intermodulation formulas of weak nonlinear systems, after introducing negative feedback, the second-order and third-order intermodulation of the closed-loop negative feedback system are:

[0056]

[0057]

[0058] It can be seen that negative feedback can reduce the second-order intermodulation of the main amplifier A IIP2 Under the condition of g2≈0, the negative feedback structure increases the A of the main amplifier. IIP3 Improvement (1+T0) 3 / 2 times.

[0059] In the embodiments of the present application, the linearity of the low-noise broadband amplifier can be improved by adopting a negative feedback structure, thereby solving the problem in the related art that it is difficult to realize an amplifier with a wide operating frequency, high linearity and low noise coefficient.

[0060] Figure 3 is a connection diagram of a low noise amplifier according to an embodiment of the present application, such as Figure 3 As shown, the low noise amplifier also includes the following structure:

[0061] a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6.

[0062] In this embodiment, the first capacitor C1 is the same as the second capacitor C2, the third capacitor C3 is the same as the fifth capacitor C5, and the fourth capacitor C4 is the same as the sixth capacitor C6.

[0063] In this embodiment, the first capacitor C1 is connected between the first input terminal and the input terminal of the first main amplifier, and is used to input the first input signal into the first main amplifier (110).

[0064] In this embodiment, the second capacitor C2 is connected between the second input terminal and the input terminal of the second main amplifier, and is used to input the second input signal into the second main amplifier (120).

[0065] In this embodiment, the third capacitor C3 is connected between the output end of the first feedback amplifier and the input end of the first main amplifier, and is used to input the first feedback signal output by the first feedback amplifier (130) into the first main amplifier (110).

[0066] In this embodiment, the fourth capacitor C4 is connected between the output end of the second main amplifier and the input end of the first feedback amplifier, and is used to input the second output signal output by the second main amplifier (120) into the first feedback amplifier (130).

[0067] In this embodiment, the fifth capacitor C5 is connected between the output end of the second feedback amplifier and the input end of the second main amplifier, and is used to input the second feedback signal output by the second feedback amplifier (140) into the second main amplifier (120).

[0068] In this embodiment, the sixth capacitor C6 is connected between the output end of the first main amplifier and the input end of the second feedback amplifier, and is used to input the first output signal output by the first main amplifier (110) into the second feedback amplifier (140).

[0069] In this embodiment, the capacitor is an AC coupling capacitor, and its main function is to isolate DC and pass AC. For example, the first capacitor C1 is used to isolate the DC signal in the first input signal and input the AC signal in the first input signal into the first main amplifier (110); the second capacitor C2 is used to isolate the DC signal in the second input signal and input the AC signal in the second input signal into the second main amplifier (120).

[0070] In an exemplary embodiment, the fifth capacitor C5 and the sixth capacitor C6 may be variable capacitors, and other capacitors may be selected according to design requirements. The present application does not limit the size of the capacitors.

[0071] Figure 4 is a connection diagram of another low noise amplifier according to an embodiment of the present application. Figure 4 As shown, the amplifier also includes the following structures:

[0072] The first feedback resistor Rf1 and the second feedback resistor Rf2.

[0073] In this embodiment, the first feedback resistor Rf1 is the same as the second feedback resistor Rf2.

[0074] In this embodiment, the first feedback resistor Rf1 is connected between the output end of the first feedback amplifier and the third capacitor C3, and is used to input the first feedback signal output by the first feedback amplifier (130) into the first main amplifier (110) through the third capacitor C3.

[0075] In this embodiment, the second feedback resistor Rf2 is connected between the output end of the second feedback amplifier and the fifth capacitor C5, and is used to input the second feedback signal output by the second feedback amplifier (140) into the second main amplifier (120) through the fifth capacitor C5.

[0076] Through the embodiments of the present application, a feedback resistor is connected in series at the output end of each feedback amplifier, so as to adjust the matching and expand the bandwidth.

[0077] In an exemplary embodiment, the first main amplifier (110) and the second main amplifier (120) are respectively one of the following: a common-source amplifier, a common-source common-gate amplifier, a common-emitter amplifier, and an amplifier based on an inverter structure.

[0078] In an exemplary embodiment, the first feedback amplifier (130) and the second feedback amplifier (140) are respectively one of the following: the common-source amplifier, the common-source common-gate amplifier, the common-emitter amplifier, and the amplifier based on the inverter structure.

[0079] Furthermore, the main amplifier and the feedback amplifier may be inverting amplifiers with the same or different structures.

[0080] Figure 5 is a schematic diagram of an amplifier structure based on an inverter structure according to an embodiment of the present application, such as Figure 5 As shown, the amplifier based on the inverter structure includes the following structures:

[0081] P-channel MOS field effect transistor PMOS tube and N-channel MOS field effect transistor NMOS tube.

[0082] In this embodiment, the PMOS tube and the NMOS tube are current multiplexing structures, and the input signal (IN) of the amplifier based on the inverter structure is input into the PMOS tube and the NMOS tube from the gate of the PMOS tube and the gate of the NMOS tube respectively, and the output signal (OUT) of the amplifier based on the inverter structure is output from the drain of the PMOS tube and the drain of the NMOS tube, wherein the drain of the PMOS tube is directly connected to the drain of the NMOS tube, the source of the PMOS tube is connected to the positive power supply, and the source of the NMOS tube is connected to the negative power supply.

[0083] In an exemplary embodiment, the amplifier based on the inverter structure further includes the following structure: a first resistor Rb, a third feedback resistor Rf3 and a seventh capacitor C7.

[0084] In this embodiment, the third feedback resistor Rf3 is connected between the drain and the gate of the PMOS tube to provide a DC bias voltage for the PMOS tube. Further, the third feedback resistor can be designed as a sliding resistor to facilitate the adjustment of the bias voltage.

[0085] In this embodiment, the first resistor Rb1 is connected between the gate of the NMOS transistor and the first bias voltage Vb1, and is used to provide a DC bias voltage for the NMOS transistor.

[0086] In this embodiment, the seventh capacitor C7 is connected between the gate of the NMOS tube and the gate of the PMOS tube, and is used to isolate the DC bias voltage of the NMOS tube from the input signal of the PMOS tube.

[0087] The amplifier based on the inverter structure in the embodiment of the present application can be a main amplifier or a feedback amplifier. Further, since the amplifier of the present application is a symmetrical structure with differential input and output, when the first main amplifier (110) is an amplifier based on the inverter structure, the second main amplifier (120) is also an amplifier based on the inverter structure, and the NMOS tube, PMOS tube, capacitor, resistor and bias voltage used by the two are the same. Similarly, when the first feedback amplifier (130) is an amplifier based on the inverter structure, the second feedback amplifier (140) is also an amplifier based on the inverter structure.

[0088] Figure 6 is a schematic diagram of the structure of a common source amplifier according to an embodiment of the present application (I), such as Figure 6 As shown, the common source amplifier includes the following structures:

[0089] A P-channel MOS field effect transistor (PMOS) and a first load.

[0090] In this embodiment, the source of the PMOS tube is connected to the positive power supply (AVDD), and the drain of the PMOS tube is grounded via the first load.

[0091] In an exemplary embodiment, the common-source amplifier may further include a second resistor Rb2 .

[0092] In this embodiment, the second resistor Rb2 is connected between the gate of the PMOS tube and the second bias voltage Vb2, and is used to provide a DC bias voltage for the PMOS tube.

[0093] In this embodiment, the first load may be a resistor, a diode, or Figure 6 An NMOS tube connected as a diode, wherein the gate and drain of the NMOS tube are short-circuited.

[0094] Figure 7 is a structural schematic diagram (II) of a common source amplifier according to an embodiment of the present application, such as Figure 7 As shown, the common source amplifier includes the following structures:

[0095] N-channel MOS field effect transistor NMOS tube and a second load.

[0096] In this embodiment, the source of the NMOS tube is grounded, and the drain of the NMOS tube is connected to the positive power supply via the second load.

[0097] In an exemplary embodiment, the common-source amplifier may further include a third resistor Rb3 .

[0098] In this embodiment, the third resistor Rb3 is connected between the gate of the NMOS transistor and the third bias voltage Vb3, and is used to provide a DC bias voltage for the NMOS transistor.

[0099] In this embodiment, the second load can be a resistor, a diode, or Figure 7 A PMOS tube connected in the middle to form a diode, wherein the gate and drain of the PMOS tube are short-circuited.

[0100] In the implementation of the present application, in addition to the inverting amplifier structure in the above exemplary embodiment, technicians can also select an inverting amplifier with any structure such as a cascode amplifier, a common emitter amplifier, etc.

[0101] Figure 8 is a schematic diagram of the structure of an amplifier with differential input and output and cross feedback structure according to an embodiment of the present application (I), such as Figure 8 As shown, the main amplifier in the amplifier adopts an amplifier based on an inverter structure, and the feedback amplifier adopts a common-source amplifier based on PMOS.

[0102] In this embodiment, the amplifier adopts a bilaterally symmetrical differential structure. The two differential input signals are input from INP and INN respectively. The capacitor is an AC coupling capacitor. The first NMOS transistor NM1 and the first PMOS transistor PM1 form an inverter-based main amplifier.

[0103] In this embodiment, the NMOS tube and the PMOS tube in the main amplifier use a current multiplexing structure, which is beneficial to reducing the power consumption of the amplifier.

[0104] In this embodiment, the gate DC bias of NM1 is provided by an external bias voltage via a first resistor Rb1. PM1 adopts gate self-biasing, which is provided by a third feedback resistor Rf3 connected between the drain and gate of PM1.

[0105] In the embodiment of the present application, compared with the use of external bias for both NMOS and PMOS tubes, the structure of biasing PMOS with the third feedback resistor Rf3 can stabilize the DC operating point of the amplifier. At the same time, due to the presence of the feedback resistor, it is conducive to more flexible adjustment of input impedance matching and bandwidth expansion. Furthermore, the main amplifier introduces complementary derivative superposition technology, using the characteristics of the third-order nonlinear coefficient g3 of the transconductance of the PMOS tube and the NMOS tube being close in absolute value and opposite in sign within a certain input voltage range. By selecting appropriate PMOS and NMOS sizes and DC bias points, the third-order nonlinear component of the transconductance can be offset within a certain input voltage range, thereby improving the input third-order intermodulation IIP3 of the amplifier.

[0106] In this embodiment, the differential output signal OUTN (ie, the first output signal) and OUTP (ie, the second output signal) of the main amplifier are connected to the input of the negative feedback amplifier in a cross-coupling manner via coupling capacitors C4 and C6.

[0107] In this embodiment, the negative feedback amplifier is composed of two MOS tubes, a second PMOS tube PM2 and a second NMOS tube NM2. PM2 is used as a common source amplifier, and the gate and drain of NM2 are short-circuited into a diode as the load of PM2 (ie, the first load).

[0108] In this embodiment, the second bias voltage Vb2 in the feedback amplifier provides a DC bias point for the feedback amplifier through the second resistor Rb2.

[0109] In the embodiment of the present application, since the common source structure can achieve a gain greater than 1, the active negative feedback circuit adopts a common source structure instead of a commonly used source follower structure to achieve a higher negative feedback gain, which is beneficial to improving the overall linearity of the amplifier. At the same time, the common source amplifier has better noise performance than the source follower, which is beneficial to reducing the noise coefficient of the feedback path. The output of the feedback amplifier is connected in series with feedback resistors Rf1 and Rf2 to adjust the matching and expand the bandwidth.

[0110] In an exemplary embodiment, in order to increase the near-zero value range of the nonlinear component, a high power supply voltage of 1.8V may be used.

[0111] Through the embodiments of the present application, the linearity of the broadband low noise amplifier can be effectively improved without significantly reducing the noise performance. Furthermore, the embodiments of the present application expand the bandwidth of the low noise amplifier, so that the amplifier has a stable gain in an ultra-wide frequency band.

[0112] Fig. 9 is a schematic diagram of the structure of an amplifier with differential input and output and cross feedback structure according to an embodiment of the present application (II), such as Fig. 9 As shown, the main amplifier in the amplifier adopts an amplifier based on an inverter structure, and the feedback amplifier adopts a common-source amplifier based on NMOS.

[0113] In this embodiment, the first NMOS transistor NM1 and the first PMOS transistor PM1 form a main amplifier based on an inverter structure.

[0114] In this embodiment, the negative feedback amplifier is composed of two MOS tubes, a second PMOS tube PM2 and a second NMOS tube NM2. NM2 is used as a common source amplifier. The gate and drain of PM2 are short-circuited into a diode as the load of PM2 (ie, the second load).

[0115] In this embodiment, the third bias voltage Vb3 in the feedback amplifier provides a DC bias point for the feedback amplifier through the third resistor Rb3.

[0116] In an exemplary embodiment, the main amplifier may also use an amplifier structure that is an inverting amplifier, such as a cascode amplifier, a common source amplifier, or a common emitter amplifier.

[0117] In an exemplary embodiment, the feedback amplifier may also adopt an amplifier structure based on an inverter structure, a cascode amplifier, or a common emitter amplifier, all of which are inverting amplifier structures.

[0118] In an exemplary embodiment, the elements constituting the inverting amplifier are not limited to MOS (oxide semiconductor, Metal Oxide Semiconductor) elements, and bipolar junction (BJT) may also be used, such as a common emitter amplifier composed of bipolar elements.

[0119] Fig.10 is a schematic diagram of amplifier gain comparison according to an embodiment of the present application, such as Fig.10 As shown, the circle represents the amplifier gain of active feedback in the embodiment of the present application, and the triangle represents the amplifier gain without introducing active feedback in the related art.

[0120] Fig.11 is a schematic diagram of comparison of amplifier reflection coefficients according to an embodiment of the present application. Fig.11 As shown, the circle is the reflection coefficient of the amplifier with active feedback introduced in the embodiment of the present application, and the triangle is the reflection coefficient of the amplifier without active feedback introduced in the related art.

[0121] Fig.12 is a schematic diagram of comparing amplifier noise coefficients according to an embodiment of the present application. Fig.12 As shown, the circle is the noise coefficient of the amplifier with active feedback introduced in the embodiment of the present application, and the triangle is the noise coefficient of the amplifier without active feedback introduced in the related art.

[0122] Fig.13 is a schematic diagram of amplifier linearity comparison according to an embodiment of the present application. Fig.13 As shown, the circle represents the linearity of the amplifier with active feedback introduced in the embodiment of the present application, and the triangle represents the linearity of the amplifier without active feedback introduced in the related art.

[0123] Through the embodiments of the present application, the linearity of the amplifier can be effectively improved while ensuring the low noise and wide bandwidth of the amplifier, thereby ensuring the working effect of the amplifier.

[0124] An embodiment of the present application further provides a radio frequency receiver, which includes the low noise amplifier in any one of the above embodiments.

[0125] An embodiment of the present application further provides an electronic device, which includes the low noise amplifier in any one of the above embodiments.

[0126] In one example, the amplifier in the embodiment of the present application is a broadband low-noise amplifier, which is generally used in the radio frequency front end of a wireless communication system receiver, and the electronic device is, for example, a base station or other equipment.

[0127] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0128] The above is only an exemplary embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low noise amplifier, characterized in that: The invention comprises a first main amplifier (110), a second main amplifier (120), a first feedback amplifier (130) and a second feedback amplifier (140), wherein the low noise amplifier has a first input end, a second input end, a first output end and a second output end, wherein the first input end and the second input end are used to respectively receive a first input signal and a second input signal, and the first output end and the second output end are used to respectively output a first output signal and a second output signal amplified by the low noise amplifier, wherein the first input signal and the second input signal are a pair of differential input signals, wherein: The first main amplifier (110) and the second main amplifier (120) have the same structure, the first feedback amplifier (130) and the second feedback amplifier (140) have the same structure, and the first main amplifier (110), the second main amplifier (120), the first feedback amplifier (130) and the second feedback amplifier (140) are all inverting amplifiers; The input end of the first main amplifier (110) is connected to the first input end of the low noise amplifier and the output end of the first feedback amplifier, the output end of the first main amplifier is connected to the input end of the second feedback amplifier and the first output end of the low noise amplifier, the first main amplifier receives the first input signal and the first feedback signal output by the first feedback amplifier and performs inverse amplification to obtain a first output signal and outputs the first output signal at the output end of the first main amplifier; The second feedback amplifier (140) is used to amplify the first output signal from the output end of the first main amplifier to obtain a second feedback signal and output the second feedback signal at the output end of the second feedback amplifier; The input end of the second main amplifier (120) is connected to the second input end of the low noise amplifier and the output end of the second feedback amplifier, the output end of the second main amplifier is connected to the input end of the first feedback amplifier and the second output end of the low noise amplifier, the second main amplifier receives the second input signal and the second feedback signal output by the second feedback amplifier and performs inverse amplification to obtain a second output signal and outputs the second output signal at the output end of the second main amplifier; The first feedback amplifier (130) is used to amplify the second output signal from the output end of the second main amplifier to obtain the first feedback signal and output the first feedback signal at the output end of the first feedback amplifier.

2. The low noise amplifier according to claim 1, characterized in that: The low noise amplifier further comprises: A first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6, wherein the first capacitor C1 is the same as the second capacitor C2, the third capacitor C3 is the same as the fifth capacitor C5, and the fourth capacitor C4 is the same as the sixth capacitor C6; The first capacitor C1 is connected between the first input terminal and the input terminal of the first main amplifier, and is used to input the first input signal into the first main amplifier (110); The second capacitor C2 is connected between the second input terminal and the input terminal of the second main amplifier, and is used to input the second input signal into the second main amplifier (120); The third capacitor C3 is connected between the output end of the first feedback amplifier and the input end of the first main amplifier, and is used to input the first feedback signal output by the first feedback amplifier (130) into the first main amplifier (110); The fourth capacitor C4 is connected between the output end of the second main amplifier and the input end of the first feedback amplifier, and is used to input the second output signal output by the second main amplifier (120) into the first feedback amplifier (130); The fifth capacitor C5 is connected between the output end of the second feedback amplifier and the input end of the second main amplifier, and is used to input the second feedback signal output by the second feedback amplifier (140) into the second main amplifier (120); The sixth capacitor C6 is connected between the output end of the first main amplifier and the input end of the second feedback amplifier, and is used to input the first output signal output by the first main amplifier (110) into the second feedback amplifier (140).

3. The low noise amplifier according to claim 2, characterized in that: The low noise amplifier further comprises: A first feedback resistor Rf1 and a second feedback resistor Rf2, wherein the first feedback resistor Rf1 is the same as the second feedback resistor Rf2; The first feedback resistor Rf1 is connected between the output end of the first feedback amplifier and the third capacitor C3, and is used to input the first feedback signal output by the first feedback amplifier (130) into the first main amplifier (110) through the third capacitor C3; The second feedback resistor Rf2 is connected between the output end of the second feedback amplifier and the fifth capacitor C5, and is used to input the second feedback signal output by the second feedback amplifier (140) into the second main amplifier (120) through the fifth capacitor C5.

4. The low noise amplifier according to claim 1, characterized in that: The first main amplifier (110) and the second main amplifier (120) are respectively one of the following: a common source amplifier, a common source and common gate amplifier, a common emitter amplifier, and an amplifier based on an inverter structure; The first feedback amplifier (130) and the second feedback amplifier (140) are respectively one of the following: a common-source amplifier, a common-source common-gate amplifier, a common-emitter amplifier, and an amplifier based on an inverter structure.

5. The low noise amplifier according to claim 4, characterized in that: The amplifier based on the inverter structure includes: a P-channel MOS field effect transistor PMOS tube and an N-channel MOS field effect transistor NMOS tube, wherein: The input signal of the amplifier based on the inverter structure is input to the PMOS tube and the NMOS tube from the gate of the PMOS tube and the gate of the NMOS tube respectively, and the output signal of the amplifier based on the inverter structure is output from the drain of the PMOS tube and the drain of the NMOS tube, wherein the drain of the PMOS tube is directly connected to the drain of the NMOS tube, the source of the PMOS tube is connected to the positive power supply, and the source of the NMOS tube is connected to the negative power supply.

6. The low noise amplifier according to claim 5, characterized in that: The amplifier based on the inverter structure further includes: a first resistor Rb1, a third feedback resistor Rf3 and a seventh capacitor C7, wherein: The third feedback resistor Rf3 is connected between the drain and the gate of the PMOS tube, and is used to provide a DC bias voltage for the PMOS tube; The first resistor Rb1 is connected between the gate of the NMOS tube and the first bias voltage Vb1, and is used to provide a DC bias voltage for the NMOS tube; The seventh capacitor C7 is connected between the gate of the NMOS tube and the gate of the PMOS tube, and is used to isolate the DC bias voltage of the NMOS tube from the input signal of the PMOS tube.

7. The low noise amplifier according to claim 4, characterized in that: The common source amplifier comprises: a P-channel MOS field effect transistor (PMOS) and a first load; The source of the PMOS tube is connected to a positive power supply, and the drain of the PMOS tube is grounded via the first load.

8. The low noise amplifier according to claim 7, characterized in that: The common source amplifier further includes: a second resistor Rb2; The second resistor Rb2 is connected between the gate of the PMOS tube and the second bias voltage Vb2, and is used to provide a DC bias voltage for the PMOS tube.

9. The low noise amplifier according to claim 7, characterized in that: The first load includes one of the following: a resistor, a diode, and an N-channel MOS field effect transistor (NMOS), wherein the gate and drain of the NMOS are short-circuited.

10. The low noise amplifier according to claim 4, characterized in that: The common source amplifier comprises: an N-channel MOS field effect transistor (NMOS) and a second load; The source of the NMOS tube is grounded, and the drain of the NMOS tube is connected to a positive power supply via the second load.

11. The low noise amplifier according to claim 10, characterized in that: The common source amplifier further includes: a third resistor Rb3; The third resistor Rb3 is connected between the gate of the NMOS tube and the third bias voltage Vb3, and is used to provide a DC bias voltage for the NMOS tube.

12. The low noise amplifier according to claim 10, characterized in that: The second load includes one of the following: a resistor, a diode, and a P-channel MOS field effect transistor (PMOS), wherein the gate and drain of the PMOS are short-circuited.

13. The low noise amplifier according to claim 4, characterized in that: The first main amplifier (110) and the second main amplifier (120) are amplifiers based on an inverter structure, wherein the amplifiers based on the inverter structure include: a first PMOS transistor PM1, a first NMOS transistor NM1, a first resistor Rb1, a third feedback resistor Rf3 and a seventh capacitor C7; The first feedback amplifier (130) and the second feedback amplifier (140) are common source amplifiers, wherein the common source amplifier comprises: a second PMOS tube PM2, a second resistor Rb2 and a second NMOS tube NM2, wherein the gate and the drain of the second PMOS tube PM2 are short-circuited, or the gate and the drain of the second NMOS tube NM2 are short-circuited.

14. A radio frequency receiver, characterized in that: The radio frequency receiver comprises the low noise amplifier as claimed in any one of claims 1 to 13.

15. An electronic device, characterized in that: The electronic device comprises the low noise amplifier described in any one of claims 1 to 13.

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