An adaptive-biased low noise amplifier protection device

Abstract

The application provides a self-adaptive bias low-noise amplifier protection device, comprising a low-noise amplifier, a directional coupler, a detection circuit, a self-adaptive protection module, a radio frequency switch and a signal conditioning circuit; wherein the self-adaptive protection module comprises an analog-to-digital converter, a data processing module, an I / O port and a digital-to-analog converter; the data processing module pre-stores a radio frequency switch flag signal, a bias voltage value under a normal working state of the low-noise amplifier and a lookup table of different bias voltage values corresponding to different voltage reading values converted by the analog-to-digital converter; the data processing module firstly determines whether the circuit needs to be disconnected from the radio frequency switch for protection through the voltage reading value; secondly, determines whether the bias voltage value of the low-noise amplifier needs to be changed so as to work in a linear region through the voltage reading value; and if the bias voltage value needs to be changed, the appropriate value is outputted according to the voltage reading value.

Description

Technical Field

[0001] This invention relates to the fields of microwave measurement and electronic information, and specifically to a low-noise amplifier protection device with adaptive bias. Background Technology

[0002] High-power microwaves are an evolving concept. Traditionally, high-power microwaves refer to electromagnetic waves with power exceeding 100 MW and frequencies between 1 and 300 GHz. However, the concept and development of high-power microwaves have expanded to include strong electromagnetic radiation with an average power greater than 1 MW.

[0003] High-power microwave (HPM) systems use high-gain antennas to directionally emit high-power microwaves, illuminating targets and causing interference or damage to their electronic equipment. Based on the coupling path of high-power microwaves to electronic equipment, it can generally be divided into "front-door" and "back-door" coupling. "Front-door" coupling refers to high-power microwaves entering the system through an antenna within the electronic system. When the frequency band of the high-power microwaves used falls within the operating frequency band of the target system, this coupling method poses a significant threat to radio frequency (RF) equipment. "Back-door" coupling refers to coupling formed by the incident wave through holes, seams, cable joints, etc., in the target system's casing. Therefore, "front-door" coupling has a particularly severe impact on the RF front-end.

[0004] High-power microwaves can directly irradiate the "front door" antenna of a device, thus entering the device's radio frequency link. Furthermore, the time-frequency domain characteristics of high-power microwaves result in a large coupling magnitude at the front door, causing the coupling energy to exceed the interference and damage thresholds of various semiconductor devices, leading to irreversible damage. Therefore, designing a protective module at the "front door" capable of shielding against ultra-wideband high-power microwaves has significant application value.

[0005] Currently, there are two main "front-door" protection measures to protect electronic equipment from high-power microwaves. One is field protection, which uses the different responses of protective devices under different fields to "filter" useful signals and reflect high-energy signals. The other is path protection, installed on the equipment link. When the RF front-end passes a high-energy signal, the protection module activates to discharge the high-energy signal, thus protecting the downstream link from impact. However, regardless of the protection method, current low-noise amplifiers are insufficient for high-power microwave protection and are susceptible to damage. Therefore, designing an adaptive bias low-noise amplifier protection device is crucial for protecting electronic equipment from electromagnetic interference and damage. Summary of the Invention

[0006] This invention provides an adaptive bias low-noise amplifier protection device that can be used to protect electronic equipment from electromagnetic interference and electromagnetic damage.

[0007] The technical solution adopted in this invention is as follows:

[0008] An adaptive bias low-noise amplifier protection device includes: a low-noise amplifier, a directional coupler, a detector circuit, an adaptive protection module, a radio frequency switch, and a signal conditioning circuit.

[0009] The through-hole output of the directional coupler is connected to the input of the radio frequency switch;

[0010] The output terminal of the radio frequency switch is connected to the input terminal of the low noise amplifier;

[0011] The output of the low-noise amplifier provides radio frequency output to the next stage circuit.

[0012] The output of the coupling terminal of the directional coupler is connected to the input terminal of the detector circuit. The directional coupler couples the signal that matches the envelope detection processing requirements to the detector circuit, that is, the directional coupler couples the signal that conforms to the processing standard of the detector circuit to the detector circuit.

[0013] The output terminal of the detection circuit is connected to the input terminal of the adaptive protection module;

[0014] The adaptive protection module includes two output terminals: the first output terminal is connected to the control terminal of the RF switch, and the second output terminal is connected to the input terminal of the signal conditioning circuit.

[0015] The output of the signal conditioning circuit is connected to the bias voltage input of the low-noise amplifier.

[0016] The adaptive protection module is used to detect and process the signal output by the detection circuit. When the detected signal exceeds the safety threshold of the low noise amplifier, a control signal is output through the first output port of the adaptive protection module to disconnect the RF switch to protect the circuit; otherwise, the bias voltage output to the signal conditioning circuit is adjusted in real time to make the low noise amplifier work in its linear operating region.

[0017] Furthermore, the adaptive protection module includes: an analog-to-digital converter, a data processing module, an I / O port, and a digital-to-analog converter;

[0018] The signal output by the detector circuit is converted into a corresponding digital signal by an analog-to-digital converter and then transmitted to the data processing module. The data processing module is used to detect and process the signal output by the detector circuit.

[0019] The data processing module includes two output terminals. The first output terminal of the data processing module is connected to the input terminal of the I / O port, and the output terminal of the I / O port (i.e., the first output terminal of the adaptive protection module) is connected to the input terminal of the RF switch. The second output terminal of the data processing module is connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter (i.e., the second output terminal of the adaptive protection module) is connected to the input terminal of the signal conditioning circuit.

[0020] Furthermore, the data processing module performs detection and processing on the signal output by the detection circuit as follows:

[0021] The data processing module is pre-set with the gate voltage and drain voltage of the low-noise amplifier under normal operating conditions, and a RF switch flag variable with a data length of 1 bit. When the value is 1, it indicates that the switch is on; when the value is 0, it indicates that the switch is off.

[0022] When the data processing module detects that the voltage reading after the analog-to-digital converter is greater than the safety threshold of the low-noise amplifier, it sets the RF switch flag variable to 0 to disconnect the connection between the I / O port and the input terminal connected to the RF switch; at the same time, the output values ​​of the gate voltage and drain voltage of the low-noise amplifier are both set to 0, and then input to the digital-to-analog converter through the second output terminal of the data processing module.

[0023] When the data processing module detects that the current voltage reading is less than or equal to the safety threshold of the low-noise amplifier, it continues to detect whether the voltage value output by the analog-to-digital converter is less than or equal to a specified second threshold. If so, the RF switch flag variable is set to 1, and the gate voltage and drain voltage of the low-noise amplifier under normal operating conditions are used as the output values ​​of the gate voltage and drain voltage. If the voltage value is greater than the second threshold, the RF switch flag variable is set to 1, and the gate voltage and drain voltage values ​​that match the current voltage reading are used as the output values ​​of the gate voltage and drain voltage. The output values ​​are then input to the digital-to-analog converter through the second output terminal of the data processing module.

[0024] The second threshold is less than the safety threshold.

[0025] Furthermore, the data processing module is equipped with a data lookup table for voltage value readings. The data lookup table is used to record the gate voltage and drain voltage of the low-noise amplifier corresponding to each voltage value reading obtained by experimental measurement. It adopts a hash table structure so that each voltage value reading output from the analog-to-digital converter has a corresponding gate and drain voltage value.

[0026] Furthermore, the safety threshold is the maximum voltage value in the data lookup table, and the second threshold is the minimum value in the data lookup table.

[0027] Furthermore, all internal connections and input / output terminals of the adaptive protection module, as well as the output terminal of the signal conditioning circuit, are control circuits.

[0028] Furthermore, the input terminal of the RF switch, the output terminal of the directional coupler, the output terminal of the RF switch, and the output terminal of the low-noise amplifier are all RF lines, connected by coaxial cables.

[0029] Furthermore, the detection circuit performs amplitude demodulation on the output signal of the coupling end of the directional coupler for processing by the analog-to-digital converter of the adaptive protection module.

[0030] Furthermore, the analog-to-digital converter converts the analog signal output from the detector circuit into a digital signal, so that the processing module can read and process the data.

[0031] The technical solution provided by this invention brings at least the following beneficial effects:

[0032] This invention enables the low-noise amplifier (LNA) of an RF receiver to possess a certain degree of anti-interference capability in complex electromagnetic environments. This is manifested in: when external interference signals exceed the linear operating range of the LNA, timely measures are taken to bring it back into the linear range to maintain good operating performance; when the received signal exceeds the safety threshold of the LNA, the transmission link is promptly disconnected to ensure the safety of the LNA and the link. This invention can adaptively adjust the distorted LNA to the linear operating range and disconnect circuits in cases of excessive interference to protect the circuit, achieving the goal of resisting external signal interference and improving reception stability in high-power millimeter-wave reception applications. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the circuit structure of an adaptive bias low-noise amplifier protection device provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the processing process of the processing module in an embodiment of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0037] The radio frequency (RF) signal received by the antenna can be better analyzed and processed by the subsequent circuitry after being processed by the low-noise amplifier (LNA). However, to prevent the LNA from deviating from its linear region due to external signal instability and strong electromagnetic interference, thus degrading its performance or even damaging it, this embodiment proposes using a directional coupler and detection circuit to extract a portion of the RF signal to monitor the LNA's operating state. An adaptive protection module then processes this information to control the LNA's bias voltage, ensuring it always operates within the linear region. Furthermore, when external interference signals are too strong, the RF switch is disconnected to protect the circuitry.

[0038] As one possible implementation, an adaptive bias low-noise amplifier protection device provided in this embodiment of the invention includes: a low-noise amplifier, a directional coupler, a detector circuit, an adaptive protection module, a radio frequency switch, and a signal conditioning circuit; wherein, the adaptive protection module includes an analog-to-digital converter, a data processing module, an I / O port, and a digital-to-analog converter; an antenna receives external radio frequency input to the input terminal of the directional coupler; the through-hole output of the directional coupler is connected to the input terminal of the radio frequency switch; the output terminal of the radio frequency switch is connected to the input terminal of the low-noise amplifier; the output terminal of the low-noise amplifier provides radio frequency output to the next-level circuit; the coupling terminal output of the directional coupler is connected to the input terminal of the detector circuit, and the directional coupler couples signals conforming to the processing standard of the detector circuit to the detector circuit (i.e., an envelope detector); the output terminal of the detector circuit ( Figure 1 A) shown is connected to the input of the adaptive protection module. The adaptive protection module has two outputs: the first output is connected to the RF switch control terminal; the second output is connected to the input of the signal conditioning circuit; and the output of the signal conditioning circuit is connected to the bias voltage input of the low-noise amplifier.

[0039] For the adaptive protection module, external signals are input to the analog-to-digital converter (ADC) input terminal through its input terminal; the ADC output terminal is connected to the data processing module input terminal; the data processing module includes two output terminals. Figure 1 The output ports B and C shown are as follows: Port B is connected to the I / O port input. The data processing module determines whether it is necessary to disconnect the RF switch to protect the circuit by reading the data value converted by the analog-to-digital converter. The output of the I / O port (port D) is the first output of the adaptive protection module, which is connected to the RF switch input. Port C of the data processing module is connected to the digital-to-analog converter input. If it is not necessary to disconnect the RF switch, the data processing module determines the magnitude of the new bias voltage to be output by reading the data value converted by the analog-to-digital converter and outputs it. The second output of the digital-to-analog converter (port C) is the second output of the adaptive protection module, which is connected to the signal conditioning circuit input.

[0040] In this embodiment, a directional coupler couples part of the signal to the subsequent processing circuit, and an analog-to-digital converter converts the analog signal output from the detection circuit into a digital signal. This digital signal is then input to the data processing module for further processing.

[0041] In this embodiment, the data processing module needs to pre-store the low-noise amplifier gate voltage V under normal operating conditions. g_ori Drain voltage V d_ori It is also necessary to set the radio frequency switch flag variable SW_Flag. When its value is 1, it indicates that the switch is on; when its value is 0, it indicates that the switch is off.

[0042] In this embodiment, a feasible lookup table is shown in Table 1. The lookup table consists of three rows and several columns, using a hash table structure, and the algorithm's time complexity is O(1). The first row contains the input values ​​of the hash function, and the voltage reading value AD_Data after conversion by the analog-to-digital converter will be used as the input value for the lookup. The second and third rows contain the gate voltage values ​​V corresponding to different inputs. g (i) Drain voltage V d (i), as shown in Table 1:

[0043] Table 1

[0044] AD_Data V_min V_min+1 V_min+2 …… V_min+n Vg_out Vg(0) Vg(1) Vg(2) …… Vg(n) Vd_out Vd(0) Vd(1) Vd(2) …… Vd(n)

[0045] In Table 1, the voltage values ​​are arranged in ascending order, and n represents the number of data items.

[0046] In this embodiment, the data processing module's processing procedure is as follows: Figure 2 As shown, specifically: the data processing module first determines whether the voltage reading AD_Data after conversion by the analog-to-digital converter is greater than the first voltage threshold V in the lookup table. min +n means looking up the maximum value in the table. If it is greater than this value, the gate voltage output value V will be increased. g_out Drain voltage output value V d_out The RF switch flag value SW_Flag is set to 0, the RF switch and bias voltage input are disconnected, the protection circuit is activated, and the program ends; if it is less than this value, the program continues to run.

[0047] In this embodiment, the data processing module further determines whether the voltage reading AD_Data after conversion by the analog-to-digital converter is less than the second voltage threshold V in the lookup table. min This involves finding the minimum value in the table. If the value is less than this, the gate voltage V under normal operating conditions is set to... g_ori Drain voltage V d_ori The values ​​are respectively assigned to the gate voltage output value V. g_outand drain voltage output value V d_out The RF switch flag SW_Flag is set to 1, and the program ends; if it is greater than this value, the gate voltage value V corresponding to V(i) that is equal to AD_Data is found. g (i) Drain voltage V d (i) are assigned to the gate voltage output value V respectively. g_out and output drain voltage output value V d_out The RF switch flag value SW_Flag is set to 1, and the program ends.

[0048] In this embodiment, if necessary, the signal conditioning circuit is responsible for shaping and filtering the output of the analog-to-digital converter, ultimately outputting the bias voltage to the low-noise amplifier. That is, in this embodiment, the voltage value output by the adaptive protection module is typically relatively small, which may not be able to drive the low-noise amplifier. Simultaneously, the output signal of the adaptive protection module may be unstable and noisy. Therefore, the signal conditioning circuit is needed to amplify and filter the signal output by the adaptive protection module before finally outputting it to the low-noise amplifier.

[0049] This embodiment can adaptively adjust the low-noise amplifier with distortion to the linear operating region and disconnect the circuit when subjected to strong interference to protect the circuit, thereby achieving the purpose of resisting external signal interference and improving reception stability in high-power microwave receiving application scenarios.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0051] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A low-noise amplifier protection device with adaptive bias, characterized in that, include: Low-noise amplifier, directional coupler, detector circuit, adaptive protection module, RF switch and signal conditioning circuit; The through-hole output of the directional coupler is connected to the input of the radio frequency switch; The output terminal of the radio frequency switch is connected to the input terminal of the low noise amplifier; The output of the low-noise amplifier provides radio frequency output to the next stage circuit. The output of the coupling terminal of the directional coupler is connected to the input terminal of the detection circuit, and the directional coupler couples a signal that matches the envelope detection processing requirements to the detection circuit; The output terminal of the detection circuit is connected to the input terminal of the adaptive protection module; The adaptive protection module includes two output terminals: the first output terminal is connected to the control terminal of the RF switch, and the second output terminal is connected to the input terminal of the signal conditioning circuit. The output of the signal conditioning circuit is connected to the bias voltage input of the low-noise amplifier. The adaptive protection module is used to detect and process the signal output by the detection circuit. When the detected signal exceeds the safety threshold of the low noise amplifier, a control signal is output through the first output port of the adaptive protection module to disconnect the RF switch to protect the circuit; otherwise, the bias voltage output to the signal conditioning circuit is adjusted in real time to make the low noise amplifier work in its linear operating region.

2. The apparatus as claimed in claim 1, characterized in that, The adaptive protection module includes: an analog-to-digital converter, a data processing module, I / O ports, and a digital-to-analog converter; The signal output by the detector circuit is converted into a corresponding digital signal by an analog-to-digital converter and then transmitted to the data processing module. The data processing module is used to detect and process the signal output by the detector circuit. The data processing module includes two output terminals. The first output terminal of the data processing module is connected to the input terminal of the I / O port, and the output terminal of the I / O port is connected to the input terminal of the RF switch. The second output terminal of the data processing module is connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is connected to the input terminal of the signal conditioning circuit.

3. The apparatus as described in claim 2, characterized in that, The data processing module performs detection and processing on the signal output by the detection circuit as follows: The data processing module is pre-set with the gate voltage and drain voltage of the low-noise amplifier under normal operating conditions, and a RF switch flag variable with a data length of 1 bit. When the value is 1, it indicates that the switch is on; when the value is 0, it indicates that the switch is off. When the data processing module detects that the voltage reading after the analog-to-digital converter is greater than the safety threshold of the low-noise amplifier, it sets the RF switch flag variable to 0 to disconnect the connection between the I / O port and the input terminal connected to the RF switch. At the same time, the output values ​​of the gate voltage and drain voltage of the low-noise amplifier are both set to 0. Then, the data is input to the digital-to-analog converter through the second output terminal of the data processing module. When the data processing module detects that the current voltage value reading is less than or equal to the safety threshold of the low noise amplifier, it continues to detect whether the voltage value output by the analog-to-digital converter is less than or equal to the specified second threshold. If so, the RF switch flag variable is set to 1, and the gate voltage and drain voltage of the low noise amplifier under normal operating conditions are used as the output values ​​of the gate voltage and drain voltage. If the voltage is greater than the second threshold, the RF switch flag variable is set to 1, and the gate voltage and drain voltage values ​​that match the current voltage value reading are used as the output values ​​of the gate voltage and drain voltage. The data is then input to the digital-to-analog converter via the second output of the data processing module. The second threshold is less than the safety threshold.

4. The apparatus as claimed in claim 2, characterized in that, The data processing module is equipped with a data lookup table for voltage readings. The data lookup table is used to record the gate voltage and drain voltage of the low-noise amplifier corresponding to each voltage reading obtained by experimental measurement. It adopts a hash table structure so that each voltage reading output from the analog-to-digital converter has a corresponding gate and drain voltage value.

5. The apparatus as described in claim 4, characterized in that, The safety threshold is the maximum voltage value in the data lookup table, and the second threshold is the minimum value in the data lookup table.

6. The apparatus as claimed in claim 2, characterized in that, The internal connections and all input / output terminals of the adaptive protection module, as well as the output terminal of the signal conditioning circuit, are all control lines.

7. The apparatus as claimed in claim 1, characterized in that, The input terminal of the RF switch, the output terminal of the directional coupler, the output terminal of the RF switch, and the output terminal of the low-noise amplifier are all RF lines, connected by coaxial cables.

8. The apparatus as claimed in claim 2, characterized in that, The detection circuit performs amplitude demodulation on the output signal of the coupling end of the directional coupler for processing by the analog-to-digital converter of the adaptive protection module.

9. The apparatus as claimed in claim 2, characterized in that, The analog-to-digital converter converts the analog signal output from the detector circuit into a digital signal, enabling the processing module to read and process the data.

Images