Anti-interference circuit and anti-interference chip

Abstract

The embodiment of the present invention discloses an anti-interference circuit and chip, the circuit includes an input module, a 2.4GHz filter network module, a 5.8GHz low noise amplifier module body and an output module connected in sequence. The anti-interference circuit also includes a power module and a bypass capacitor, the power module is connected to the 5.8GHz low noise amplifier module body, one end of the bypass capacitor is connected to the power module, and the other end is grounded; the 5.8GHz low noise amplifier module body includes an inductor L D The anti-interference circuit provided in the embodiment of the present invention introduces a bypass capacitor between the power supply and the ground, and the bypass circuit and the inductor L D The relationship between them is #imgabs0#, that is, the capacitance of the bypass capacitor is designed to be and the inductor L D Resonance is 2.45GHz. After experimental simulation, the anti-interference ability of the anti-interference circuit is greatly improved without increasing the chip cost.

Description

Technical Field

[0001] The present invention relates to the field of chip technology, and in particular to an anti-interference circuit and an anti-interference chip. Background Art

[0002] WiFi is a commonly used communication transceiver system, which generally uses two frequency bands, namely 2.4GHz-2.5GHz and 4.9GHz-5.8GHz, hereinafter referred to as 2.4GHz and 5.8GHz. Figure 1 As shown, the signal from the 2.4 GHz transmitter will be coupled through the antenna, thereby causing greater interference to the 5.8 GHz receiver.

[0003] To solve the above interference problem, Figure 2 As shown in FIG. 1 , the existing solution is to add a filter network before the low-noise amplifier (LNA) of the front-end module (FEM) of the 5.8GHz receiver to attenuate the 2.4GHz signal. However, due to the limitations of the chip inductor Q value and other aspects, a single attenuation network can only attenuate the 2.4GHz signal by about 21dB. Figure 3 shown.

[0004] If the anti-interference capability of the 5.8GHz receiver needs to be improved, more filter networks must be added. However, LNA is a noise-sensitive module, and adding filter networks at will will worsen the noise. In addition, the inductor in the filter network occupies too large an area, and using additional inductors to improve anti-interference capabilities will also significantly increase chip costs. Summary of the invention

[0005] In view of the technical defects mentioned in the background technology, an object of the embodiments of the present invention is to provide an anti-interference circuit and an anti-interference chip.

[0006] To achieve the above objectives, in the first aspect, an embodiment of the present invention provides an anti-interference circuit, comprising an input module, a 2.4GHz filter network module, a 5.8GHz low noise amplifier module body and an output module connected in sequence. The anti-interference circuit also includes a power module and a bypass capacitor C, the power module is connected to the 5.8GHz low noise amplifier module body, one end of the bypass capacitor C is connected to the power module, and the other end is grounded;

[0007] The 5.8GHz low noise amplifier module body includes an inductor L D , the bypass capacitor and the inductor L D The following relationship must be satisfied:

[0008]

[0009] Wherein, f=2.45GHz.

[0010] As a specific implementation of the present application, the 5.8GHz low noise amplifier module body also includes an M1 tube, an M2 tube, an inductor Ls and an output matching network, the M1 tube is respectively connected to the 2.4GHz filter network module, the M2 tube and one end of the inductor Ls, the other end of the inductor Ls is grounded, and the inductor Ls is grounded. D One end is connected to the power module, and the other end is respectively connected to the M2 tube and the output matching network, and the output matching network is connected to the output module.

[0011] As a specific implementation of the present application, the output matching network includes a resistor R1, a capacitor C1, a capacitor C2 and an inductor L1, one end of the resistor R1 is connected to the inductor L D one end of the inductor L1 and the other end of the inductor C1; the other end of the capacitor C1 is connected to one end of the inductor L1 and one end of the capacitor C2; the other end of the capacitor C2 is grounded; the other end of the inductor L1 is connected to the output module.

[0012] As a specific implementation of the present application, the 2.4 GHz filter network module includes an inductor L2 and a capacitor C3, one end of the inductor L2 is connected to the input module, and the other end is connected to one end of the capacitor C3; the other end of the capacitor C3 is grounded.

[0013] As a specific implementation of the present application, the input module is an LNA input interface, and the output module is an LNA output interface.

[0014] In a second aspect, an embodiment of the present invention further provides an anti-interference chip, which includes the anti-interference circuit as described in the first aspect above.

[0015] The anti-interference circuit and chip provided in the embodiment of the present invention introduce a bypass capacitor between the power supply and the ground, and the bypass circuit and the inductor L D The satisfying relationship between That is, the capacitance of the bypass capacitor is designed to be equal to the inductor L D Resonance is 2.45GHz. After experimental simulation, the anti-interference ability of the anti-interference circuit is greatly improved without increasing the chip cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation of the present invention or the technical solution in the prior art, the drawings required for use in the specific implementation or the description of the prior art are briefly introduced below.

[0017] Figure 1 It is a schematic diagram of the transmitter and the receiver;

[0018] Figure 2It is a schematic diagram of the front-end structure of a 5.8GHz receiver after adding a filtering network in the prior art;

[0019] Figure 3 It is a signal attenuation diagram after adding a filter network in the prior art;

[0020] Figure 4 is a structural block diagram of an anti-interference circuit provided by an embodiment of the present invention;

[0021] Figure 5 yes Figure 4 A circuit diagram of an anti-interference circuit shown;

[0022] Figure 6 yes Figure 4 Another circuit diagram of the anti-interference circuit shown;

[0023] Figure 7 is a signal attenuation diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] Based on the technical problems existing in the background technology, the inventive concept of the present invention is to improve the suppression degree of the 2.4 GHz frequency band without adding any additional devices.

[0027] Please refer to Figure 4 The anti-interference circuit provided in the embodiment of the present invention includes an input module, a 2.4GHz filter network module, a 5.8GHz low noise amplifier module body, an output module, a power module and a bypass capacitor C. The power module is connected to the 5.8GHz low noise amplifier module body, one end of the bypass capacitor C is connected to the power module, and the other end is grounded; the input module, the 2.4GHz filter network module, the 5.8GHz low noise amplifier module body and the output module are connected in sequence.

[0028] As a specific implementation method, Figure 4 The circuit diagram of the anti-interference circuit is shown in Figure 5Please refer to Figure 4 and Figure 5 , the input module is an LNA input interface, and the output module is an LNA output interface.

[0029] The 2.4 GHz filter network module includes an inductor L2 and a capacitor C3. One end of the inductor L2 is connected to the input module, and the other end is connected to one end of the capacitor C3. The other end of the capacitor C3 is grounded.

[0030] Furthermore, the 5.8 GHz low noise amplifier module body also includes an inductor L D , M1 tube, M2 tube, inductor Ls and output matching network, M1 tube is respectively connected to the 2.4GHz filter network module, M2 tube and one end of the inductor Ls, the other end of the inductor Ls is grounded, D One end is connected to the power module, and the other end is respectively connected to the M2 tube and the output matching network, and the output matching network is connected to the output module.

[0031] For further information, please refer to Figure 6 The output matching network includes a resistor R1, a capacitor C1, a capacitor C2 and an inductor L1. One end of the resistor R1 is connected to the inductor L D one end of the inductor L1 and the other end of the inductor C1; the other end of the capacitor C1 is connected to one end of the inductor L1 and one end of the capacitor C2; the other end of the capacitor C2 is grounded; the other end of the inductor L1 is connected to the output module.

[0032] It should be noted that if Figure 6 As shown, the inductor L D Can be placed in the output matching network.

[0033] against Figure 5 or Figure 6 In order to improve the suppression capability of 2.4 GHz, the bypass circuit is designed as a chip internal capacitor in this embodiment, and its capacitance is designed to be equal to the inductor L D Resonant at 2.45GHz, the expression is as follows:

[0034]

[0035] In the above formula, f = 2.45GHz, L D The size of depends on the specific design and needs to be adjusted after using this design. In this example, the adjusted L D Changing the capacitance value will slightly affect the output matching and gain. The circuit can be made close to the original state by simply fine-tuning the output matching network, keeping the in-band gain and output matching basically unchanged.

[0036] Please refer to Figure 6, the principle of the anti-interference circuit is:

[0037] The signal enters the LNA from the input end, and the signal in the 2.4GHz frequency band is initially suppressed by the filtering network. The useful signal reaches the gate end of M1 in the form of voltage, is converted into a current signal by M1 and M2, and reaches the output matching network. Finally, it is sent to the next module from the output port in the form of power.

[0038] According to the above anti-interference circuit, the simulation results are as follows: Figure 7 As shown in the figure, it can be seen that the suppression effect of the anti-interference circuit in this embodiment on the 2.4 GHz frequency band is about 34 dB, which is 13 dB higher than that of the prior art.

[0039] In summary, the anti-interference circuit provided in the embodiment of the present invention introduces a bypass capacitor between the power supply and the ground, and the bypass circuit and the inductor L D The satisfying relationship between That is, the capacitance of the bypass capacitor is designed to be equal to the inductor L D Resonance is 2.45GHz. After experimental simulation, the anti-interference ability of the anti-interference circuit is greatly improved without increasing the chip cost.

[0040] In addition, unlike the traditional solution, in this embodiment, the bypass capacitor is placed inside the chip instead of outside, so that the chip can accurately control the bypass capacitor.

[0041] Based on the same inventive concept, an embodiment of the present invention further provides an anti-interference chip, which includes the above-mentioned anti-interference circuit.

[0042] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An anti-interference circuit, comprising an input module, a 2.4GHz filter network module, a 5.8GHz low noise amplifier module body and an output module connected in sequence, characterized in that: The anti-interference circuit also includes a power supply module and a bypass capacitor C, the power supply module is connected to the main body of the 5.8GHz low noise amplifier module, one end of the bypass capacitor C is connected to the power supply module, and the other end is grounded; The 5.8GHz low noise amplifier module body includes an inductor L D , the bypass capacitor and the inductor L D The following relationship must be satisfied: Where, f = 2.45 GHz; The 5.8GHz low noise amplifier module body also includes an M1 tube, an M2 tube, an inductor Ls and an output matching network. The M1 tube is respectively connected to the 2.4GHz filter network module, the M2 tube and one end of the inductor Ls, and the other end of the inductor Ls is grounded. D One end is connected to the power module, and the other end is respectively connected to the M2 tube and the output matching network, and the output matching network is connected to the output module; The output matching network includes a resistor R1, a capacitor C1, a capacitor C2 and an inductor L1. One end of the resistor R1 is connected to the inductor L1. D one end of the inductor L1 and the other end of the inductor L1; the other end of the inductor C1 is connected to one end of the inductor L1 and one end of the capacitor C2; the other end of the capacitor C2 is grounded; the other end of the inductor L1 is connected to the output module; The 2.4 GHz filter network module includes an inductor L2 and a capacitor C3, one end of the inductor L2 is connected to the input module, and the other end is connected to one end of the capacitor C3; the other end of the capacitor C3 is grounded; The input module is an LNA input interface, and the output module is an LNA output interface.

2. An anti-interference chip, characterized in that: The anti-interference circuit comprises the anti-interference circuit as claimed in claim 1.

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