阅读说明：本技术 一种低噪声放大器 (Low-noise amplifier ) 是由 张秀娟 于 2020-06-18 设计创作，主要内容包括：本发明实施例公开了一种低噪声放大器,该低噪声放大器包括：第一放大管、与该第一放大管连接的第二放大管,以及与该第一放大管连接的负反馈单元。其中,第一放大管的漏端接地,该第一放大管的栅端与信号源连接,该第一放大管的源端与第二放大管的漏端连接,该第二放大管的源端与低噪声放大器的输出端连接；该负反馈单元分别与第一放大管的栅端、第一放大管的源端连接。本发明实施例提供一种低噪声放大器,可以解决低噪声放大器的放大效果较差的问题。(The embodiment of the invention discloses a low noise amplifier, which comprises: the amplifier comprises a first amplifying tube, a second amplifying tube connected with the first amplifying tube, and a negative feedback unit connected with the first amplifying tube. The drain end of the first amplifying tube is grounded, the grid end of the first amplifying tube is connected with a signal source, the source end of the first amplifying tube is connected with the drain end of the second amplifying tube, and the source end of the second amplifying tube is connected with the output end of the low-noise amplifier; the negative feedback unit is respectively connected with the grid end of the first amplifying tube and the source end of the first amplifying tube. The embodiment of the invention provides a low-noise amplifier, which can solve the problem of poor amplification effect of the low-noise amplifier.)

1. A low noise amplifier, comprising: the negative feedback amplifier comprises a first amplifying tube, a second amplifying tube connected with the first amplifying tube and a negative feedback unit connected with the first amplifying tube;

the drain end of the first amplifying tube is grounded, the gate end of the first amplifying tube is connected with a signal source, the source end of the first amplifying tube is connected with the drain end of the second amplifying tube, and the source end of the second amplifying tube is connected with the output end of the low noise amplifier; the negative feedback unit is respectively connected with the grid end of the first amplifying tube and the source end of the first amplifying tube.

2. The low noise amplifier of claim 1, wherein the negative feedback unit is configured to generate noise to cancel the noise generated by the first and second amplifier tubes.

3. The low noise amplifier of claim 1, wherein the negative feedback unit comprises a first resistor; the first end of the first resistor is connected with the grid end of the first amplifying tube, the second end of the first resistor is connected with the source end of the first amplifying tube, and the second end of the first resistor is further connected with the drain end of the second amplifying tube.

4. The low noise amplifier of claim 1, wherein the negative feedback unit comprises a first resistor; the first end of the first resistor is connected with the grid end of the first amplifier tube, the first end of the first resistor is further connected with the grid end of the second amplifier tube, the second end of the first resistor is connected with the source end of the first amplifier tube, and the second end of the first resistor is further connected with the drain end of the second amplifier tube.

5. The low noise amplifier of any one of claims 1 to 4, further comprising a first inductor; the first end of the first inductor is connected with the signal source, and the second end of the first inductor is connected with the gate end of the first amplifying tube.

6. The low noise amplifier of any one of claims 1 to 4, further comprising a second inductor; the first end of the second inductor is grounded, and the second end of the second inductor is connected with the drain end of the first amplifying tube.

7. The low noise amplifier of any one of claims 1 to 4, further comprising a third inductor; the first end of the third inductor is connected with the source end of the second amplifying tube, and the second end of the third inductor is connected with the output end of the low noise amplifier.

Technical Field

The embodiment of the invention relates to the technical field of microwaves, in particular to a low-noise amplifier.

Background

The low noise amplifier, which is a key circuit module in a wireless radio frequency communication device, can be set in the high frequency or intermediate frequency of a radio receiver to serve as a preamplifier. In general, the noise figure and bandwidth of the lna directly determine the overall noise figure and bandwidth of the rf receiver.

However, in the related art, the noise figure of the low noise amplifier is good, but the bandwidth characteristic of the low noise amplifier is poor, so that the amplification effect of the low noise amplifier is poor.

Disclosure of Invention

The embodiment of the invention provides a low-noise amplifier, which can solve the problem of poor amplification effect of the low-noise amplifier.

In order to solve the technical problem, the embodiment of the invention adopts the following technical scheme:

in a first aspect of embodiments of the present invention, a low noise amplifier is provided, where the low noise amplifier includes: the amplifier comprises a first amplifying tube, a second amplifying tube connected with the first amplifying tube, and a negative feedback unit connected with the first amplifying tube. The drain end of the first amplifying tube is grounded, the grid end of the first amplifying tube is connected with a signal source, the source end of the first amplifying tube is connected with the drain end of the second amplifying tube, and the source end of the second amplifying tube is connected with the output end of the low-noise amplifier; the negative feedback unit is respectively connected with the grid end of the first amplifying tube and the source end of the first amplifying tube.

In an embodiment of the present invention, a low noise amplifier includes: the amplifier comprises a first amplifying tube, a second amplifying tube connected with the first amplifying tube, and a negative feedback unit connected with the first amplifying tube. The drain end of the first amplifying tube is grounded, the grid end of the first amplifying tube is connected with a signal source, the source end of the first amplifying tube is connected with the drain end of the second amplifying tube, and the source end of the second amplifying tube is connected with the output end of the low-noise amplifier; the negative feedback unit is respectively connected with the grid end of the first amplifying tube and the source end of the first amplifying tube. Since the input signal Vin is in the first amplifier tube M₁A second amplifier tube M₂Is in opposite phase at the gate terminal and the drain terminal, and the first resistor R₁The phases of the generated noises at the two points are in phase, so that the two noises in phase act on the two ends of the grid source of the amplifier tube, and the difference value of the two noises is obtained by the second amplifier tube M₂Amplifying and forming voltage at the output end, and forming noise cancellation to a certain extent due to the same phase of the two, thereby eliminating the first resistor R to a certain extent₁The additional noise brought by the noise amplifier can improve the amplification effect of the noise amplifier.

Drawings

Fig. 1 is a circuit diagram of a low noise amplifier according to an embodiment of the present invention;

fig. 2 is a second circuit diagram of a low noise amplifier according to an embodiment of the present invention;

fig. 3 is a third circuit diagram of a low noise amplifier according to an embodiment of the present invention;

FIG. 4 is a fourth circuit diagram of a low noise amplifier according to an embodiment of the present invention;

fig. 5 is a fifth circuit diagram of a low noise amplifier according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first" and "second," and the like, in the description and in the claims of embodiments of the present invention are used for distinguishing between different objects and not for describing a particular order of the objects. For example, the first and second amplifier tubes, etc. are used to distinguish between different amplifier tubes, and are not used to describe a particular order of amplifier tubes.

In the description of the embodiments of the present invention, the meaning of "a plurality" means two or more unless otherwise specified. For example, a plurality of elements refers to two elements or more.

The term "and/or" herein is an association relationship describing an associated object, and means that there may be three relationships, for example, a display panel and/or a backlight, which may mean: there are three cases of a display panel alone, a display panel and a backlight at the same time, and a backlight alone. The symbol "/" herein denotes a relationship in which the associated object is or, for example, input/output denotes input or output.

In the embodiments of the present invention, words such as "exemplary" or "for example" are used to mean serving as examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "e.g.," an embodiment of the present invention is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

An embodiment of the present invention provides a low noise amplifier, including: the amplifier comprises a first amplifying tube, a second amplifying tube connected with the first amplifying tube, and a negative feedback unit connected with the first amplifying tube. The drain end of the first amplifying tube is grounded, the grid end of the first amplifying tube is connected with a signal source, the source end of the first amplifying tube is connected with the drain end of the second amplifying tube, and the source end of the second amplifying tube is connected with the output end of the low-noise amplifier; the negative feedback unit is respectively connected with the grid end of the first amplifying tube and the source end of the first amplifying tube. Since the input signal Vin is in the first amplifier tube M₁A second amplifier tube M₂Is in opposite phase at the gate terminal and the drain terminal, and the first resistor R₁The phases of the generated noises at the two points are in phase, so that the two noises in phase act on the two ends of the grid source of the amplifier tube, and the difference value of the two noises is obtained by the second amplifier tube M₂Amplifying and forming voltage at the output end, and forming noise cancellation to a certain extent due to the same phase of the two, thereby eliminating the first resistor R to a certain extent₁The additional noise brought by the noise amplifier can improve the amplification effect of the noise amplifier.

A low noise amplifier provided by the embodiment of the present invention is described in detail below with reference to the accompanying drawings by specific embodiments and application scenarios thereof.

As shown in fig. 1, the low noise amplifier according to the embodiment of the present invention includes: first amplifier tube M₁And a first amplifier tube M₁Second amplifying tube M connected₂And with the first amplifier tube M₁A negative feedback unit 10 connected.

In the embodiment of the invention, the first amplifying tube M₁The drain terminal of the first amplifier tube M is grounded₁The gate terminal of the first amplifier tube M is connected with a signal source₁Source end and second amplifier tube M₂Is connected to the drain terminal of the second amplifier tube M₂The source end of the low-noise amplifier is connected with the output end of the low-noise amplifier; the negative feedback unit 10 is connected to the first amplifierPipe M₁Gate terminal of, first amplifier tube M₁Is connected with the source end of the transformer.

It will be appreciated that the first amplification tube M can be used₁The negative feedback unit 10 is connected in parallel between the gate end and the drain end of the low noise amplifier, so that the bandwidth of the inductance source negative feedback low noise amplifier is increased by the loop gain times, and the circuit bandwidth can be effectively increased. Through formula derivation and small signal analysis, it can be found that the polarities of the noise generated by the negative feedback unit 10 at the two ends of the negative feedback unit 10 are in-phase, and the polarities of the useful signal at the two ends of the negative feedback unit 10 are in-phase. Therefore, the circuit structure can be designed, and the results of useful signal superposition and noise signal cancellation can be realized.

Optionally, in an embodiment of the present invention, the first amplifying tube M is₁Specifically, the second amplifier tube M may be an MOS tube₂Specifically, the tube may be a cascade tube.

It can be understood that a noise-cancelled negative feedback low noise amplifier can be formed by short-circuiting the gate terminals of the amplifier tube (i.e., the first amplifier tube) and the cascode tube (i.e., the second amplifier tube) while adding the negative feedback unit 10. Through small signal analysis, noise signals of a gate end and a source end of the cascode tube are in phase, a useful signal is in phase opposition, and an output signal Vout is amplification of a difference value of gate-source voltages of the cascode tube, so that the structure can effectively reduce noise contribution brought by resistance.

Optionally, in the embodiment of the present invention, the negative feedback unit 10 is configured to generate noise to cancel the first amplifier tube M₁And a second amplifier tube M₂The noise generated.

Optionally, in a possible embodiment of the present invention, referring to fig. 1 and fig. 2, the negative feedback unit 10 includes a first resistor R₁(ii) a The first resistor R₁First end of and first amplifier tube M₁The first resistor R₁Second end of and first amplifier tube M₁Is connected to the source terminal of the first resistor R₁And a second amplifying tube M₁The drain terminal of (1) is connected.

Optionally, in another aspect of the present inventionIn one possible embodiment, referring to fig. 1 and fig. 3, the negative feedback unit 10 includes a first resistor R₁(ii) a The first resistor R₁First end of and first amplifier tube M₁The first resistor R₁The first end of the first amplifier tube M₂The first resistor R₁Second end of and first amplifier tube M₁Is connected to the source terminal of the first resistor R₁And a second amplifying tube M₂The drain terminal of (1) is connected.

Optionally, in the embodiment of the present invention, the input signal Vin output by the signal source passes through the first amplifying tube M₁Into a low noise amplifier, M₁Is connected to ground. The drain end of the first amplifying tube M1 is connected with the second amplifying tube M₂While the first amplifier tube M₁And a second amplifier tube M₂Are connected together, a resistor R₁Both ends are respectively connected with M₁And M₂Gate terminal and drain terminal. Second amplifier tube M₂The drain terminal of the transistor is connected with a power supply VDD, and an output signal Vout is positioned at M₂At the drain end.

Compared with the traditional inductance source negative feedback low noise amplifier, the low noise amplifier has the advantages that the bandwidth of the circuit is improved by adding the feedback resistor, and the noise caused by the feedback resistor is eliminated to a certain extent by connecting the grid ends of the amplifying tube and the cascode tube in a short circuit mode. Therefore, the invention can simultaneously realize the requirements of broadband and low noise, and can be applied to the front ends of various radio frequency receivers.

Optionally, in the embodiment of the present invention, with reference to fig. 1, as shown in fig. 4 and 5, the low noise amplifier further includes a first inductor L₁(ii) a Wherein, the first inductance L₁Is connected with a signal source, a first inductor L₁Second end of and first amplifier tube M₁The grid end of the grid is connected; the low noise amplifier further comprises a second inductor L₂(ii) a Wherein the second inductor L₂The first terminal of the second inductor L is grounded, and the second inductor L₂The second end of the first amplifier tube is connected with the drain end of the first amplifier tube; the low noise amplifier further comprises a third inductor L₃(ii) a Wherein the third inductor L₃First end of and second amplifier tube M₂Is connected to the source terminal of the third inductor L₃Is connected to the output of the low noise amplifier.

It can be understood that the input signal Vin passes through the inductor L₁Into the circuit, the first inductor L₁The other end of the first amplifier tube M is connected with the first amplifier tube M₁，M₁Source end of which is connected with a second inductor L₂The second inductance L₂And the other end of which is connected to ground. First amplifier tube M₁The drain end of the first amplifier tube is connected with a second amplifier tube M₂While the first amplifier tube M₁And a second amplifier tube M₂Are connected together, a first resistor R₁Two ends of the first amplifier tube M are respectively connected with₁And a second amplifier tube M₂Gate terminal and drain terminal. Second amplifier tube M₂The drain terminal of the inductor is connected with a third inductor L₃The third inductor L₃The other end of the second amplifier is connected with a power supply VDD, and an output signal Vout is positioned in the second amplifier tube M₂Drain terminal and third inductor L₃The joint of (1).

In the embodiment of the invention, the useful signal is in the first amplifying tube M₁A second amplifier tube M₂The phases at the gate terminal and the drain terminal of (a) are inverted; a first resistor R₁The resulting noise is in phase at these two points. Two same-phase noises act on two ends of a grid source of the amplifier tube, and the difference value of the two noises is amplified by a second amplifier tube M₂Amplifying and forming voltage at the output end, and forming noise cancellation to a certain extent due to the same phase of the two, thereby eliminating the first resistor R to a certain extent₁Additional noise is introduced. The useful signal is in opposite phase at two ends of the gate and source of the amplifier tube, and the difference between the useful signal and the useful signal is amplified by the second amplifier tube M₂And the signal is amplified to the output end to form signal superposition to a certain extent, so that the gain of the circuit is improved.

An embodiment of the present invention provides a low noise amplifier, including: the amplifier comprises a first amplifying tube, a second amplifying tube connected with the first amplifying tube, and a negative feedback unit connected with the first amplifying tube. Wherein the drain terminal of the first amplifier tube is grounded, the gate terminal of the first amplifier tube is connected with a signal source, and the first amplifier tubeThe source end of the second amplifier tube is connected with the output end of the low noise amplifier; the negative feedback unit is respectively connected with the grid end of the first amplifying tube and the source end of the first amplifying tube. Since the input signal Vin is in the first amplifier tube M₁A second amplifier tube M₂Is in opposite phase at the gate terminal and the drain terminal, and the first resistor R₁The phases of the generated noises at the two points are in phase, so that the two noises in phase act on the two ends of the grid source of the amplifier tube, and the difference value of the two noises is obtained by the second amplifier tube M₂Amplifying and forming voltage at the output end, and forming noise cancellation to a certain extent due to the same phase of the two, thereby eliminating the first resistor R to a certain extent₁The additional noise brought by the noise amplifier can improve the amplification effect of the noise amplifier.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.