Low-noise amplifier and radio frequency chip

Abstract

The present invention is suitable for the technical field of wireless communications, and particularly relates to a low-noise amplifier and a radio frequency chip. The low-noise amplifier provided by the present invention comprises a signal input end, a first notch filter circuit, an input matching circuit, a power amplification circuit, an output matching circuit, a second notch filter circuit and a signal output end. The first notch filter circuit comprises a first capacitor and a first inductor; a first end of the first inductor serves as a second input end of the first notch filter circuit; a second end of the first inductor is connected to a first end of the first capacitor; and a second end of the first capacitor serves as a first end of the first notch filter circuit. In this way, the present invention achieves out-of-band gain suppression of a low-noise amplifier and performance improvement of an index of an input second-order intercept point, so that the input and output return loss is not increased, thereby improving the performance of the low-noise amplifier.

Description

A low-noise amplifier and radio frequency chip Technical Field

[0001] The present invention is applicable to the field of wireless communication technology, and in particular relates to a low-noise amplifier and a radio frequency chip. Background Art

[0002] Low-noise amplifiers (LNAs) are an essential component of modern electronic systems, particularly in radar, communications, radio astronomy, and other fields. In these fields, LNAs are used to receive and amplify weak signals so that subsequent signal processing units can function properly.

[0003] In existing applications, to ensure signal quality amplified by low-noise amplifiers (LNAs), the 5GHz Wi-Fi frequency band places high demands on out-of-band gain suppression and second-order harmonic suppression (IIP2). Introducing separate input and output filters can cause variations in the LNA's input and output impedances, impacting performance. Furthermore, it can introduce unwanted resonances in the receiving chain, causing unnecessary oscillations.

[0004] Therefore, a new low-noise amplifier and radio frequency chip are urgently needed to solve the above problems. Summary of the Invention

[0005] The present invention provides a low-noise amplifier and a radio frequency chip, aiming to achieve out-of-band gain suppression of the low-noise amplifier and improve the performance of the input second-order intercept point index, so that the input and output return losses are not deteriorated.

[0006] In a first aspect, the present invention provides a low noise amplifier, comprising a signal input terminal, a first notch filter circuit, an input matching circuit, a power amplifier circuit, an output matching circuit, a second notch filter circuit, and a signal output terminal;

[0007] A first end of the first notch filter circuit is connected to the signal input end and the input end of the input matching circuit respectively, and a second end of the first notch filter circuit is grounded;

[0008] The input end of the power amplifier circuit is connected to the output end of the input matching circuit, the first output end of the power amplifier circuit is grounded, and the second output end of the power amplifier circuit is connected to the first input end of the output matching circuit; the second input end of the output matching circuit is used to be connected to a power supply voltage;

[0009] A first end of the second notch filter circuit is connected to the output end of the output matching circuit and the signal output end respectively, and a second end of the second notch filter circuit is grounded;

[0010] The first notch filter circuit and the second notch filter circuit are used to suppress the out-of-band gain in the low-noise amplifier; wherein, the first notch filter circuit includes a first capacitor and a first inductor, the first end of the first inductor serves as the second input end of the first notch filter circuit, the second end of the first inductor is connected to the first end of the first capacitor, and the second end of the first capacitor serves as the first end of the first notch filter circuit.

[0011] Preferably, the first notch filter circuit further includes a first Pad, a first end of the first Pad is connected to the second end of the first inductor, and a second end of the first Pad is connected to the first end of the first capacitor.

[0012] Preferably, the input matching circuit includes a second inductor and a second capacitor, the first end of the second inductor serves as the input end of the input matching circuit, the second end of the second inductor is connected to the first end of the second capacitor, and the second end of the second capacitor serves as the output end of the input matching circuit.

[0013] Preferably, the power amplifier circuit includes a third inductor, a first MOS transistor and a second MOS transistor; the first end of the third inductor serves as the first output end of the power amplifier circuit, the second end of the third inductor is connected to the source of the first MOS transistor, the gate of the first MOS transistor serves as the first input end of the power amplifier circuit, the drain of the first MOS transistor is connected to the source of the second MOS transistor, the gate of the second MOS transistor is used to be connected to an external logic control circuit, and the drain of the second MOS transistor serves as the second output end of the power amplifier circuit.

[0014] Preferably, the output matching circuit includes a fourth inductor, a third capacitor and a fourth capacitor; the first end of the fourth inductor serves as the first input end of the output matching circuit, the second end of the fourth inductor serves as the second input end of the output matching circuit, the first end of the fourth capacitor is respectively connected to the first end of the third capacitor and the first end of the fourth inductor, the second end of the fourth capacitor serves as the output end of the output matching circuit, and the second end of the third capacitor is connected to the second end of the fourth inductor.

[0015] Preferably, the second notch filter circuit includes a fifth inductor and a fifth capacitor, the first end of the fifth inductor serves as the second end of the second notch filter circuit, the second end of the fifth inductor is connected to the first end of the fifth capacitor, and the second end of the fifth capacitor serves as the first end of the second notch filter circuit.

[0016] Preferably, the second notch filter circuit further includes a second Pad, a first end of the second Pad is connected to the second end of the fifth inductor, and a second end of the second Pad is connected to the first end of the fifth capacitor.

[0017] In a second aspect, the present invention further provides a radio frequency chip, comprising the low noise amplifier as described in any one of the above embodiments.

[0018] Compared with the prior art, the low-noise amplifier proposed in the present invention includes a signal input terminal, a first notch filter circuit, an input matching circuit, a power amplifier circuit, an output matching circuit, a second notch filter circuit, and a signal output terminal; the first terminal of the first notch filter circuit is respectively connected to the signal input terminal and the input terminal of the input matching circuit, and the second terminal of the first notch filter circuit is grounded; the input terminal of the power amplifier circuit is connected to the output terminal of the input matching circuit, the first output terminal of the power amplifier circuit is grounded, and the second output terminal of the power amplifier circuit is connected to the first input terminal of the output matching circuit; the second input terminal of the output matching circuit is used to be connected to a power supply voltage; the first terminal of the second notch filter circuit is respectively connected to the output terminal of the output matching circuit and the signal output terminal, and the second terminal of the second notch filter circuit is grounded; the first notch filter circuit and the second notch filter circuit are used to suppress out-of-band gain in the low-noise amplifier; wherein the first notch filter circuit includes a first capacitor and a first inductor, the first terminal of the first inductor serves as the second input terminal of the first notch filter circuit, the second terminal of the first inductor is connected to the first terminal of the first capacitor, and the second terminal of the first capacitor serves as the first terminal of the first notch filter circuit. In this way, the present invention achieves the performance improvement of the out-of-band gain suppression and the input second-order intercept point index of the low noise amplifier, so that the input and output return losses are not deteriorated, thereby improving the performance of the low noise amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described in detail below with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made with reference to the following drawings. In the accompanying drawings:

[0020] FIG1 is a schematic diagram of the circuit structure of a low noise amplifier provided by an embodiment of the present invention.

[0021] In the figure, 100 is a low-noise amplifier, 1 is a signal input terminal, 2 is a first notch filter circuit, 3 is an input matching circuit, 4 is a power amplifier circuit, 5 is an output matching circuit, 6 is a second notch filter circuit, and 7 is a signal output terminal. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] Example 1

[0024] 1 , the present invention provides a low noise amplifier 100, which includes a signal input terminal 1, a first notch filter circuit 2, an input matching circuit 3, a power amplifier circuit 4, an output matching circuit 5, a second notch filter circuit 6, and a signal output terminal 7;

[0025] A first end of the first notch filter circuit 2 is connected to the signal input end 1 and the input end of the input matching circuit 3 respectively, and a second end of the first notch filter circuit 2 is grounded;

[0026] The input end of the power amplifier circuit 4 is connected to the output end of the input matching circuit 3, the first output end of the power amplifier circuit 4 is grounded, and the second output end of the power amplifier circuit 4 is connected to the first input end of the output matching circuit 5; the second input end of the output matching circuit 5 is used to be connected to the power supply voltage VDD;

[0027] A first end of the second notch filter circuit 6 is connected to the output end of the output matching circuit 5 and the signal output end 7 respectively, and a second end of the second notch filter circuit 6 is grounded;

[0028] The first notch filter circuit 2 and the second notch filter circuit 6 are used to suppress the out-of-band gain in the low-noise amplifier 100; wherein, the first notch filter circuit 2 includes a first capacitor C1 and a first inductor L1, the first end of the first inductor L1 serves as the second input end of the first notch filter circuit 2, the second end of the first inductor L1 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 serves as the first end of the first notch filter circuit 2.

[0029] In an embodiment of the present invention, the first notch filter circuit 2 further includes a first Pad (Pad1), a first end of the first Pad (Pad1) is connected to the second end of the first inductor L1, and a second end of the first Pad (Pad1) is connected to the first end of the first capacitor C1.

[0030] In an embodiment of the present invention, the input matching circuit 3 includes a second inductor L2 and a second capacitor C2. The first end of the second inductor L2 serves as the input end of the input matching circuit 3. The second end of the second inductor L2 is connected to the first end of the second capacitor C2. The second end of the second capacitor C2 serves as the output end of the input matching circuit 3.

[0031] In the embodiment of the present invention, the power amplifier circuit 4 includes a third inductor L3, a first MOS transistor M1, and a second MOS transistor M2; the first end of the third inductor L3 serves as the first output end of the power amplifier circuit 4, the second end of the third inductor L3 is connected to the source of the first MOS transistor M1, the gate of the first MOS transistor M1 serves as the first input end of the power amplifier circuit 4, the drain of the first MOS transistor M1 is connected to the source of the second MOS transistor M2, the gate of the second MOS transistor M2 is used to be connected to an external logic control circuit, and the drain of the second MOS transistor M2 serves as the second output end of the power amplifier circuit 4.

[0032] In the embodiment of the present invention, the output matching circuit 5 includes a fourth inductor L4, a third capacitor C3, and a fourth capacitor C4; the first end of the fourth inductor L4 serves as the first input end of the output matching circuit 5, the second end of the fourth inductor L4 serves as the second input end of the output matching circuit 5, the first end of the fourth capacitor C4 is respectively connected to the first end of the third capacitor C3 and the first end of the fourth inductor L4, the second end of the fourth capacitor C4 serves as the output end of the output matching circuit 5, and the second end of the third capacitor C3 is connected to the second end of the fourth inductor L4.

[0033] In an embodiment of the present invention, the second notch filter circuit 6 includes a fifth inductor L5 and a fifth capacitor C5. The first end of the fifth inductor L5 serves as the second end of the second notch filter circuit 6. The second end of the fifth inductor L5 is connected to the first end of the fifth capacitor C5. The second end of the fifth capacitor C5 serves as the first end of the second notch filter circuit 6.

[0034] In an embodiment of the present invention, the second notch filter circuit 6 further includes a second Pad (Pad2), a first end of the second Pad (Pad2) is connected to the second end of the fifth inductor L5, and a second end of the second Pad (Pad2) is connected to the first end of the fifth capacitor C5.

[0035] Specifically, the RF input from the signal input terminal 1 first enters the first notch filter circuit 2 composed of the first capacitor C1 and the first inductor L1. The first capacitor C1 and the first inductor L1 resonate in the frequency band to be blocked, playing a frequency selection role. The signal is then input into the low-noise amplifier 100, which has greatly weakened the spurious signals outside the operating frequency band and the signal leakage of the module, and greatly reduced the nonlinear effect of the spurious signals whose input second-order intermodulation point falls within the operating frequency band.

[0036] The second notch filter circuit 6 formed by the fifth capacitor C5 and the fifth inductor L5 at the output of the low-noise amplifier 100 also resonates in the desired blocking frequency band, further reducing the amount of out-of-band signals amplified by the low-noise amplifier 100. Furthermore, the input and output filters are designed simultaneously with the low-noise amplifier 100, ensuring that the gain within the operating frequency band of the low-noise amplifier 100 and the input and output return loss are not degraded.

[0037] And because a two-stage notch filter with input and output composed of a first notch filter circuit 2 and a second notch filter circuit 6 is designed, the two notch filters can be adjusted at different resonance points to achieve wider bandwidth out-of-band suppression and meet the suppression requirements of different frequency points.

[0038] At the same time, except for the first inductor L1 and the fifth inductor L5, all other circuits are designed on the chip. The first capacitor C1 and the fifth capacitor C5 are connected in series on the first pad (Pad1) and the second pad (Pad2), respectively. The inductance of the first inductor L1 and the fifth inductor L5 are designed on the off-chip substrate. By adjusting the inductance of the off-chip substrate while maintaining the on-chip capacitors C1 and C5, the out-of-band gain suppression points of the first notch filter circuit 2 and the second notch filter circuit 6 can be adjusted. This accelerates chip debugging, increases the practicality of the out-of-band suppression requirements of a single chip, facilitates engineering iteration and design, and speeds up the debugging cycle.

[0039] Compared with the prior art, the low-noise amplifier proposed in the present invention includes a signal input terminal, a first notch filter circuit, an input matching circuit, a power amplifier circuit, an output matching circuit, a second notch filter circuit, and a signal output terminal; the first terminal of the first notch filter circuit is respectively connected to the signal input terminal and the input terminal of the input matching circuit, and the second terminal of the first notch filter circuit is grounded; the input terminal of the power amplifier circuit is connected to the output terminal of the input matching circuit, the first output terminal of the power amplifier circuit is grounded, and the second output terminal of the power amplifier circuit is connected to the first input terminal of the output matching circuit; the second input terminal of the output matching circuit is used to be connected to a power supply voltage; the first terminal of the second notch filter circuit is respectively connected to the output terminal of the output matching circuit and the signal output terminal, and the second terminal of the second notch filter circuit is grounded; the first notch filter circuit and the second notch filter circuit are used to suppress out-of-band gain in the low-noise amplifier; wherein the first notch filter circuit includes a first capacitor and a first inductor, the first terminal of the first inductor serves as the second input terminal of the first notch filter circuit, the second terminal of the first inductor is connected to the first terminal of the first capacitor, and the second terminal of the first capacitor serves as the first terminal of the first notch filter circuit. In this way, the present invention achieves the performance improvement of the out-of-band gain suppression and the input second-order intercept point index of the low noise amplifier, so that the input and output return losses are not deteriorated, thereby improving the performance of the low noise amplifier.

[0040] Example 2

[0041] An embodiment of the present invention further provides a radio frequency chip, which includes the low noise amplifier 100 as described in the above embodiment and can achieve the same technical effects. Please refer to the description in the above embodiment, and to avoid repetition, it will not be repeated here.

[0042] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0043] The embodiments of the present invention are described above in conjunction with the accompanying drawings. What is disclosed is only a preferred embodiment of the present invention. However, the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms and equivalent changes without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A low noise amplifier, characterized in that The low noise amplifier includes a signal input terminal, a first notch filter circuit, an input matching circuit, a power amplifier circuit, an output matching circuit, a second notch filter circuit and a signal output terminal; A first end of the first notch filter circuit is connected to the signal input end and the input end of the input matching circuit respectively, and a second end of the first notch filter circuit is grounded; The input end of the power amplifier circuit is connected to the output end of the input matching circuit, the first output end of the power amplifier circuit is grounded, and the second output end of the power amplifier circuit is connected to the first input end of the output matching circuit; the second input end of the output matching circuit is used to be connected to a power supply voltage; A first end of the second notch filter circuit is connected to the output end of the output matching circuit and the signal output end respectively, and a second end of the second notch filter circuit is grounded; The first notch filter circuit and the second notch filter circuit are used to suppress the out-of-band gain in the low-noise amplifier; wherein, the first notch filter circuit includes a first capacitor and a first inductor, the first end of the first inductor serves as the second input end of the first notch filter circuit, the second end of the first inductor is connected to the first end of the first capacitor, and the second end of the first capacitor serves as the first end of the first notch filter circuit.

2. The low noise amplifier according to claim 1, wherein The first notch filter circuit further includes a first Pad, a first end of the first Pad is connected to the second end of the first inductor, and a second end of the first Pad is connected to the first end of the first capacitor.

3. The low noise amplifier according to claim 1, wherein The input matching circuit includes a second inductor and a second capacitor, the first end of the second inductor serves as the input end of the input matching circuit, the second end of the second inductor is connected to the first end of the second capacitor, and the second end of the second capacitor serves as the output end of the input matching circuit.

4. The low noise amplifier according to claim 1, wherein The power amplifier circuit includes a third inductor, a first MOS transistor, and a second MOS transistor; the first end of the third inductor serves as the first output end of the power amplifier circuit, the second end of the third inductor is connected to the source of the first MOS transistor, the gate of the first MOS transistor serves as the first input end of the power amplifier circuit, the drain of the first MOS transistor is connected to the source of the second MOS transistor, the gate of the second MOS transistor is used to be connected to an external logic control circuit, and the drain of the second MOS transistor serves as the second output end of the power amplifier circuit.

5. The low noise amplifier according to claim 1, wherein The output matching circuit includes a fourth inductor, a third capacitor, and a fourth capacitor; the first end of the fourth inductor serves as the first input end of the output matching circuit, the second end of the fourth inductor serves as the second input end of the output matching circuit, the first end of the fourth capacitor is connected to the first end of the third capacitor and the first end of the fourth inductor, respectively, the second end of the fourth capacitor serves as the output end of the output matching circuit, and the second end of the third capacitor is connected to the second end of the fourth inductor.

6. The low noise amplifier according to claim 1, wherein The second notch filter circuit includes a fifth inductor and a fifth capacitor, the first end of the fifth inductor serves as the second end of the second notch filter circuit, the second end of the fifth inductor is connected to the first end of the fifth capacitor, and the second end of the fifth capacitor serves as the first end of the second notch filter circuit.

7. The low noise amplifier according to claim 6, wherein: The second notch filter circuit further includes a second Pad, a first end of the second Pad is connected to the second end of the fifth inductor, and a second end of the second Pad is connected to the first end of the fifth capacitor.

8. A radio frequency power amplifier, characterized in that: The radio frequency power amplifier comprises the low noise amplifier according to any one of claims 1 to 7.

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