A protection circuit for a radio frequency coaxial switch

Abstract

The utility model provides a kind of protection circuit of radio frequency coaxial switch switching, comprising: inverter, D type latch, launch control signal end.The utility model provides a kind of protection circuit of radio frequency coaxial switch switching, by inverter, D type latch and launch control signal end mutual cooperation, when high power launch, launch control signal triggers D type latch locking after inverter inverting, shielding backlight control signal end switching instruction, break the limitation of traditional unprotected circuit, the arc ablation rate of switch switching under high power is reduced from 100% to 0, completely avoid switch burning, adapt to 5W above high power radio frequency scene, power filter and signal filter design guarantee anti-interference ability, solve the equipment in high power radio frequency launch state switching mechanical radio frequency coaxial switch, easy to produce arc ablation contact or directly burn switch problem, significantly improve the stability of radio frequency system and equipment service life, guarantee the stable operation of radio frequency system.

Description

Technical Field

[0001] This utility model relates to the field of radio frequency circuit protection technology, and in particular to a protection circuit for radio frequency coaxial switch switching. Background Technology

[0002] In the field of radio frequency technology, mechanical radio frequency coaxial switches are the core components for realizing radio frequency channel switching. They are widely used in communication base stations, radar systems, test and measurement instruments and other equipment. They switch between different radio frequency paths by opening and closing mechanical contacts, ensuring signal transmission between multiple channels.

[0003] Currently, in the field of radio frequency technology, there is a lack of specific protection technology for mechanical radio frequency coaxial switches. When the equipment switches the coaxial switch under high-power radio frequency signal transmission, an electric arc is easily generated when the mechanical contacts open. On the one hand, the high-temperature arc will burn the contact surface, resulting in increased contact resistance, decreased conductivity, and shortened switch life. On the other hand, when the radio frequency power exceeds the 5W threshold, switching the switch without protection circuitry will 100% burn out the mechanical radio frequency coaxial switch, causing equipment failure and economic losses, and seriously affecting the stable operation of the radio frequency system.

[0004] Therefore, it is necessary to provide a protection circuit for radio frequency coaxial switch switching to solve the above-mentioned technical problems. Utility Model Content

[0005] This invention provides a protection circuit for switching radio frequency coaxial switches, which solves the problem that when switching mechanical radio frequency coaxial switches under high-power radio frequency transmission conditions, arcing can easily occur, eroding the contacts or directly burning out the switch.

[0006] To solve the above-mentioned technical problems, this utility model provides a protection circuit for radio frequency coaxial switch switching, comprising:

[0007] The system includes an inverter, a D-type latch, a transmit control signal terminal, a backlight control signal terminal, a full circuit power supply, and a backlight control protection module. The full circuit power supply provides operating power to the inverter and the D-type latch. The transmit control signal terminal is connected to the input terminal A of the inverter, and the output terminal Y of the inverter is connected to the latch enable terminal LE of the D-type latch. The backlight control signal terminal is connected to the data input terminal D of the D-type latch, and the output terminal Q of the D-type latch is connected to the backlight control protection module. The transmit control signal terminal outputs a valid signal in high-power transmit mode, which is inverted by the inverter and then used to control the D-type latch to lock, thereby shielding the switching signal of the backlight control signal terminal.

[0008] Preferably, the power supply terminal VCC of the inverter is connected to the +3.3V output terminal of the full circuit power supply, the ground terminal GND of the inverter is connected to the common ground of the circuit, a second capacitor is connected in series between the input terminal A of the inverter and the transmit control signal terminal to filter out high-frequency noise in the transmit control signal, and a first resistor is connected to the output terminal Y of the inverter to limit the output signal current and prevent damage to subsequent circuits due to overcurrent.

[0009] Preferably, the power supply terminal VCC of the D-type latch is connected to the +3.3V output terminal of the full circuit power supply, the ground terminal GND of the D-type latch is connected to the common ground of the circuit, and the output enable terminal / OE of the D-type latch is directly connected to the common ground of the circuit, so that the D-type latch is always in the output enable state and the latching function is controlled only by the latch enable terminal LE. A sixth capacitor is connected in series between the latch enable terminal LE of the D-type latch and the output terminal Y of the inverter to filter out high-frequency noise in the latch enable signal.

[0010] Preferably, the full circuit power supply includes a power filtering module, which includes a first capacitor, a first inductor, a third capacitor, and a second inductor. The first capacitor and the first inductor are connected in series between the power supply terminals VCC and +3.3V-ALL of the inverter. The third capacitor and the second inductor are connected in series between the power supply terminals VCC and +3.3V-ALL of the D-type latch. This is used to suppress high-frequency noise and ripple on the power lines and ensure stable power supply to the inverter and the D-type latch.

[0011] Preferably, the backlight control and protection module includes a signal filtering unit, which includes a fifth capacitor connected in parallel between the output terminal Q of the D-type latch and the output terminal of the backlight control and protection module, for filtering out high-frequency interference in the output signal.

[0012] Preferably, a second resistor is connected in series between the backlight control signal terminal and the data input terminal D of the D-type latch, and the second resistor is used to limit the input current of the backlight control signal.

[0013] Preferably, a fourth capacitor is connected in parallel between the second resistor and the data input terminal D of the D-type latch. The other end of the fourth capacitor is connected to the circuit common ground. The fourth capacitor is used to filter out high-frequency noise in the backlight control signal to ensure that the data signal input to the D-type latch is stable.

[0014] Compared with related technologies, the protection circuit for radio frequency coaxial switch switching provided by this utility model has the following beneficial effects:

[0015] This invention provides a protection circuit for switching a radio frequency coaxial switch. Through the cooperation of an inverter, a D-type latch, and the transmit control signal terminal, during high-power transmission, the transmit control signal is inverted by the inverter and then triggered by the D-type latch to lock, shielding the switching command from the backlight control signal terminal. This overcomes the limitations of traditional circuits without protection, reducing the arc erosion rate during high-power switch switching from 100% to 0, completely preventing switch burnout. It is suitable for high-power radio frequency scenarios above 5W. Power supply filtering and signal filtering designs ensure anti-interference capabilities. This solves the problem of arc erosion of contacts or direct switch burnout when switching mechanical radio frequency coaxial switches under high-power radio frequency transmission conditions, significantly improving the stability of the radio frequency system and the lifespan of the equipment, ensuring stable operation of the radio frequency system. Attached Figure Description

[0016] Figure 1 A circuit diagram of a preferred embodiment of a protection circuit for radio frequency coaxial switch switching provided by this utility model;

[0017] Figure 2 This is a schematic diagram of the transmission control signal terminal circuit provided by this utility model;

[0018] Figure 3 This is a schematic diagram of the backlight control signal terminal circuit provided by this utility model;

[0019] Figure 4 A schematic diagram of the backlight control and protection module circuit provided by this utility model.

[0020] The following are the labels in the diagram: 1. Inverter; 2. D-type latch; 3. Transmit control signal terminal; 4. Backlight control signal terminal; 5. Power supply for the entire circuit; 6. Backlight control protection module; 7. First inductor; 8. Second inductor; 9. First resistor; 10. Second resistor; 11. First capacitor; 12. Second capacitor; 13. Third capacitor; 14. Fourth capacitor; 15. Fifth capacitor; 16. Sixth capacitor. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Please refer to the following: Figure 1 , Figure 2 , Figure 3 , Figure 4 ,in, Figure 1 A circuit diagram of a preferred embodiment of a protection circuit for radio frequency coaxial switch switching provided by this utility model; Figure 2 This is a schematic diagram of the transmission control signal terminal circuit provided by this utility model; Figure 3 This is a schematic diagram of the backlight control signal terminal circuit provided by this utility model; Figure 4A schematic diagram of the backlight control and protection module circuit provided by this utility model.

[0023] A protection circuit for switching an RF coaxial switch includes: an inverter 1, a D-type latch 2, a transmit control signal terminal 3, a backlight control signal terminal 4, a full circuit power supply 5, and a backlight control protection module 6. The full circuit power supply 5 provides operating power to the inverter 1 and the D-type latch 2. The transmit control signal terminal 3 is connected to the input terminal A of the inverter 1, and the output terminal Y of the inverter 1 is connected to the latch enable terminal LE of the D-type latch 2. The backlight control signal terminal 4 is connected to the data input terminal D of the D-type latch 2, and the output terminal Q of the D-type latch 2 is connected to the backlight control protection module 6. The transmit control signal terminal 3 outputs a valid signal in a high-power transmit state, which is inverted by the inverter 1 and then controls the D-type latch 2 to lock, thereby shielding the switching signal of the backlight control signal terminal 4.

[0024] In the protection circuit for the RF coaxial switch switching, inverter 1 is selected as SN74LVC1G14DBV (Schmitt trigger inverter, characterized by strong anti-interference capability and fast response speed, with a maximum propagation delay of only 8.5ns@3.3V), and D-type latch 2 is selected as SN74LVC1G373DBV (single-channel transparent D-type latch 2, supporting output enable control, suitable for 3.3V power supply scenarios). These two, along with the transmit control signal terminal 3 (TX-CTRL, serving as a monitoring node for high-power transmit status, with the signal source being the power detection unit of the RF transmit module), the backlight control signal terminal 4 (BLF-CTRL, outputting the RF coaxial switch switching command, a TTL level signal), the full circuit power supply 5 (+3.3V-ALL, employing a linear voltage regulation scheme, with output ripple ≤50mV, ensuring stable power supply to core components), and the backlight control protection module 6 (output terminal BLF-CTRL-PROT, responsible for the final filtering of the switching command), are used. The output and the circuit together form a closed-loop protection system. The power supply 5 provides a stable +3.3V operating voltage for the inverter 1 and the D-type latch 2, meeting the wide voltage operating requirements of 2.0V-5.5V for both chips. The transmit control signal terminal 3 is connected to the input terminal A of the inverter 1, which can transmit high-power transmit status signals in real time (when the transmit power is ≥5W, a high-level valid signal is output, with a voltage of 2.8V-3.3V; when the power is <5W or not transmitting, a low-level invalid signal is output, with a voltage of 0V-0.8V). The inverter 1 inverts the signal and transmits it to the latch enable terminal LE of the D-type latch 2, realizing the logical linkage of high-power signal, inversion, and trigger latch. The switching command of the backlight control signal terminal 4 needs to enter through the data input terminal D of the D-type latch 2, and then be transmitted to the backlight control protection module 6 through the output terminal Q. When the D-type latch 2 is locked, it will directly cut off the transmission path of the switching command, completely shielding the switching signal of the backlight control signal terminal 4, and avoiding the generation of arc during switching under high power conditions.

[0025] The power supply terminal VCC of inverter 1 is connected to the +3.3V output terminal of the full circuit power supply 5. The ground terminal GND of inverter 1 is connected to the common ground of the circuit. A second capacitor 12 is connected in series between the input terminal A of inverter 1 and the transmission control signal terminal 3 to filter out high-frequency noise in the transmission control signal. A first resistor 9 is connected to the output terminal Y of inverter 1 to limit the output signal current and prevent damage to subsequent circuits due to overcurrent.

[0026] The power supply terminal VCC of inverter 1 is connected to the +3.3V output terminal of the entire circuit power supply 5 through a low-impedance copper foil (0.8mm wide, grounding impedance ≤50mΩ) to ensure stable power supply. The ground terminal GND is directly connected to the circuit common ground to reduce ground bounce noise interference to logic signals. In the signal input link, the second capacitor 12 (100pF capacitance, MLCC multilayer ceramic capacitor, withstand voltage 16V) connected in series between the input terminal A of inverter 1 and the transmit control signal terminal 3 forms a high-pass filter structure, which can filter out high-frequency noise with a frequency ≥10MHz in the transmit control signal (such as harmonic interference generated by the RF transmit module and digital circuit clock noise), thus inverting the input. The signal edge of inverter 1 is smoother, avoiding noise that could cause inverter 1 to misinterpret (such as misidentifying a spike in a low level as a valid high level signal). The first resistor 9 (10kΩ, ±1% accuracy, 0402 package) connected to the output terminal Y of inverter 1 is a current-limiting resistor. According to Ohm's law (I=U / R), the output current of the inverter can be limited to within 330μA (3.3V / 10kΩ=0.33mA). Since the input leakage current of the LE terminal of D-type latch 2 is only 1μA, this current-limiting design can prevent the output of inverter 1 from being damaged by overload and also prevent excessive current from being injected into the latch, which could burn out the logic pins, thus ensuring safe signal transmission between the two circuit stages.

[0027] The power supply terminal VCC of the D-type latch 2 is connected to the +3.3V output terminal of the full circuit power supply 5. The ground terminal GND of the D-type latch 2 is connected to the common ground of the circuit. The output enable terminal / OE of the D-type latch 2 is directly connected to the common ground of the circuit, so that the D-type latch 2 is always in the output enable state. The latching function is controlled only by the latch enable terminal LE. A sixth capacitor 16 is connected in series between the latch enable terminal LE of the D-type latch 2 and the output terminal Y of the inverter 1 to filter out high-frequency noise in the latch enable signal.

[0028] The power supply terminal VCC of the D-type latch 2 is also connected to the +3.3V output terminal of the full circuit power supply 5, and a 0Ω fuse resistor is connected in series in the line (to protect the latch in case of a fault and prevent the power supply from short-circuiting and burning out the chip). The ground terminal GND is connected to the circuit common ground using the shortest path to reduce power supply noise caused by grounding impedance. To simplify the circuit control logic, the output enable terminal / OE of the D-type latch 2 is directly connected to the circuit common ground through a 0.5mm copper foil. Since this pin is active low, the latch is always in the output enabled state after grounding. No additional enable control signal is required. The enable / mask switching instruction function can be achieved simply by changing the level of the latch enable terminal LE (high level transparent, low level locked). To reduce circuit complexity and potential failure points, in the latch enable signal link, the sixth capacitor 16 (100pF capacitance, MLCC material, temperature coefficient ±10%) connected in series between the LE terminal of the D-type latch 2 and the output terminal Y of the inverter 1 can filter out high-frequency spike noise in the output signal of the inverter 1 (such as ringing noise during logic level switching). At the same time, it forms an RC filter circuit with the first resistor 9 (10kΩ) (time constant τ=R×C=10kΩ×100pF=1μs), further smoothing the signal edges and ensuring that the LE terminal signal is stable at 0V or 3.3V, avoiding the latch from switching states incorrectly due to noise (such as misidentifying noise in a high level as a low level and unlocking).

[0029] The full-circuit power supply 5 includes a power filtering module, which includes a first capacitor 11, a first inductor 7, a third capacitor 13, and a second inductor 8. The first capacitor 11 and the first inductor 7 are connected in series between the power supply terminals VCC and +3.3V-ALL of the inverter 1. The third capacitor 13 and the second inductor 8 are connected in series between the power supply terminals VCC and +3.3V-ALL of the D-type latch 2. This is used to suppress high-frequency noise and ripple on the power lines and ensure a stable power supply to the inverter 1 and the D-type latch 2.

[0030] The power filtering module of the full-circuit power supply 5 is designed with independent filtering branches for inverter 1 and D-type latch 2 to avoid power noise coupling between the two loads. The filtering branch for powering inverter 1 is composed of a first capacitor 11 (10μF capacitance, tantalum capacitor, withstand voltage 6.3V, temperature range -55℃-125℃) and a first inductor 7 (220nH inductance, 0603 package, DC resistance ≤0.5Ω) connected in series. The filtering branch for powering D-type latch 2 is composed of a third capacitor 13 (same specifications as the first capacitor 11) and a second inductor 8 (same specifications as the first inductor 7) connected in series. The first capacitor 11 and the third capacitor 13 are tantalum capacitors, which have lower equivalent series resistance (typical ESR value 50mΩ) and higher capacitance stability (capacitance fluctuation ≤10% within temperature range) compared to ceramic capacitors. They can quickly absorb instantaneous current fluctuations on the power line, ensuring the power supply continuity of the inverter and latch during high-frequency operation and avoiding logic signal distortion due to insufficient current.

[0031] The backlight control and protection module 6 includes a signal filtering unit, which includes a fifth capacitor 15. The fifth capacitor 15 is connected in parallel between the output terminal Q of the D-type latch 2 and the output terminal of the backlight control and protection module 6 to filter out high-frequency interference in the output signal.

[0032] The core function of the backlight control and protection module 6 is to perform final filtering on the switching command output by the D-type latch 2, ensuring that the signal transmitted to the RF coaxial switch is pure and interference-free. The fifth capacitor 15 (100pF capacitance, MLCC material, 16V withstand voltage) in its signal filtering unit adopts a parallel design, with one end connected to the output terminal Q of the D-type latch 2 and the other end connected to the circuit ground through a via, forming a low-pass filter structure. This capacitor can filter out high-frequency interference (≥10MHz) in the output signal (such as electromagnetic radiation interference from the RF system and signal crosstalk from adjacent circuits). Its filtering principle is: high-frequency interference signals can pass through the circuit... The low-impedance path of the capacitor flows into the ground, while the low-frequency switching command (frequency ≤ 1kHz) is retained due to the high impedance of the capacitor. The final output command signal has smooth edges and no spikes, avoiding misidentification of the command by the switch due to interference (such as misjudging noise as a switching signal). In addition, the output of the backlight control protection module 6 adopts a 50Ω impedance matching design (consistent with the input impedance of the RF coaxial switch control terminal). By adjusting the line impedance (copper foil width 0.6mm, length ≤ 10cm), the reflection loss during signal transmission is reduced, ensuring that the switching command remains at a stable level after transmission, further improving the reliability of switch control.

[0033] A second resistor 10 is connected in series between the backlight control signal terminal 4 and the data input terminal D of the D-type latch 2. The second resistor 10 is used to limit the input current of the backlight control signal.

[0034] Between the backlight control signal terminal 4 and the data input terminal D of the D-type latch 2, a second resistor 10 (10kΩ, ±1% accuracy, 0402 package) is connected in series as an input current limiting resistor. According to Ohm's law, the input current of the backlight control signal can be limited to within 330μA (3.3V / 10kΩ=0.33mA). Since the typical value of the D-terminal leakage current of the D-type latch 2 is only 1μA and the upper limit of the input withstand voltage is 5.5V, this current limiting design can effectively prevent excessive current from being injected into the D-terminal, causing the internal PN junction of the pin to break down, and at the same time prevent the backlight control signal terminal 4 from being damaged by a short circuit.

[0035] A fourth capacitor 14 is connected in parallel between the second resistor 10 and the data input terminal D of the D-type latch 2. The other end of the fourth capacitor 14 is connected to the circuit common ground. The fourth capacitor 14 is used to filter out high-frequency noise in the backlight control signal to ensure that the data signal input to the D-type latch 2 is stable.

[0036] Between the second resistor 10 and the D terminal of the D-type latch 2, a fourth capacitor 14 (100pF capacitance, MLCC material) is connected in parallel. The other end of the capacitor is connected to the circuit ground, forming a ground filtering structure, which can filter out high-frequency noise (such as clock noise and radio frequency harmonics in digital circuits) in the backlight control signal, ensuring that the signal level input to the D terminal is stable at 0V or 3.3V, and avoiding the latch from missampling data due to noise (such as missampling spike noise in low level as high level). In addition, the second resistor 10 and the fourth capacitor 14 form an RC filter circuit (time constant τ = 10kΩ × 100pF = 1μs), which can extend the rise and fall times of the backlight control signal to about 5μs, reduce the electromagnetic radiation generated when the signal jumps, meet the electromagnetic compatibility (EMC) design requirements, and avoid interference to other modules of the radio frequency system.

[0037] The working principle of the protection circuit for radio frequency coaxial switch switching provided by this utility model is as follows:

[0038] Protection logic and circuit workflow:

[0039] Low power / non-transmitting state (no protection required): When the device is in low power transmission (<5W) or non-transmitting state, the transmit control signal terminal 3 (TX-CTRL) outputs a low level (invalid signal); after the high-frequency noise is filtered out by the second capacitor 12, this low-level signal is input to the input terminal A of the inverter 1; the inverter 1 inverts the low level to a high level, and after current limiting by the first resistor 9, it is output to the latch enable terminal LE of the D-type latch 2; since the LE terminal of the D-type latch 2 is high, it is in a transparent state. The switching signal of the backlight control signal terminal 4 (BLF-CTRL) (used to control the switching of the RF coaxial switch) is current limited by the second resistor 10 and filtered by the fourth capacitor 14, and then input to the data input terminal D of the D-type latch 2. The output terminal Q follows the change of the input signal and transmits the switching signal to the backlight control protection module 6. After being filtered again by the fifth capacitor 15, the RF coaxial switch is controlled to switch normally. At this time, there is no protection action.

[0040] High-power transmission state (triggered protection): When the device starts high-power transmission (≥5W), the transmission control signal terminal 3 outputs a high level (valid signal), which is filtered by the second capacitor 12 and then input to the inverter 1; the inverter 1 inverts the high level to a low level and outputs it to the LE terminal of the D-type latch 2; the LE terminal of the D-type latch 2 becomes low and immediately enters the locked state, and the output terminal Q maintains the current level (the last valid state before locking) and no longer follows the signal change of the input terminal D; at this time, even if the backlight control signal terminal 4 outputs a new switching signal, it cannot be transmitted to the switch through the D-type latch 2, thus achieving the shielding of the switching signal and avoiding the generation of arcs when switching the switch under high power; at the same time, the power filtering module of the power supply 5 of the whole circuit (first capacitor 11 plus first inductor 7, third capacitor 13 plus second inductor 8) suppresses the interference of radio frequency noise on the power supply of inverter 1 and D-type latch 2, ensuring the stable operation of the protection logic; the sixth capacitor 16 filters out the high-frequency noise at the LE terminal to avoid false triggering of the latch state.

[0041] Normal switching resumes: When the device stops high-power transmission, the transmission control signal terminal 3 returns to low level, the inverter 1 outputs a high level to the LE terminal, the D-type latch 2 is unlocked and returns to the transparent state, the switching signal of the backlight control signal terminal 4 can be transmitted normally, and the RF coaxial switch resumes normal switching function.

[0042] Compared with related technologies, the protection circuit for radio frequency coaxial switch switching provided by this utility model has the following beneficial effects:

[0043] By cooperating with inverter 1, D-type latch 2, and transmit control signal terminal 3, the transmit control signal is inverted by inverter 1 and then triggered by D-type latch 2 to lock during high-power transmission, thus shielding the switching command of backlight control signal terminal 4. This overcomes the limitations of traditional circuits without protection, reducing the arc erosion rate of switch switching under high power from 100% to 0, completely preventing switch burnout. It is suitable for high-power RF scenarios above 5W. The power supply filtering and signal filtering design ensures anti-interference capability, solving the problem that switching mechanical RF coaxial switches under high-power RF transmission conditions can easily cause arc erosion of contacts or direct burnout of the switch. This significantly improves the stability of the RF system and the service life of the equipment, ensuring the stable operation of the RF system.

[0044] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A protection circuit for radio frequency coaxial switch switching, characterized in that, include: Inverter, D-type latch, transmit control signal terminal, backlight control signal terminal, full circuit power supply and backlight control protection module; The full circuit power supply provides operating power for the inverter and the D-type latch; The transmit control signal terminal is connected to the input terminal A of the inverter, and the output terminal Y of the inverter is connected to the latch enable terminal LE of the D-type latch. The backlight control signal terminal is connected to the data input terminal D of the D-type latch, and the output terminal Q of the D-type latch is connected to the backlight control protection module. The transmission control signal terminal outputs a valid signal in the high-power transmission state, which is inverted by the inverter and then controls the D-type latch to lock, so as to shield the switching signal of the backlight control signal terminal.

2. The protection circuit for radio frequency coaxial switch switching according to claim 1, characterized in that, The inverter's power supply terminal VCC is connected to the +3.3V output terminal of the entire circuit power supply. The inverter's ground terminal GND is connected to the circuit's common ground. A second capacitor is connected in series between the inverter's input terminal A and the transmit control signal terminal to filter out high-frequency noise in the transmit control signal. The inverter's output terminal Y is connected to a first resistor to limit the output signal current and prevent damage to subsequent circuits due to overcurrent.

3. The protection circuit for radio frequency coaxial switch switching according to claim 2, characterized in that, The power supply terminal VCC of the D-type latch is connected to the +3.3V output terminal of the full circuit power supply. The ground terminal GND of the D-type latch is connected to the common ground of the circuit. The output enable terminal / OE of the D-type latch is directly connected to the common ground of the circuit, so that the D-type latch is always in the output enable state. The latching function is controlled only by the latch enable terminal LE. A sixth capacitor is connected in series between the latch enable terminal LE of the D-type latch and the output terminal Y of the inverter to filter out high-frequency noise in the latch enable signal.

4. The protection circuit for radio frequency coaxial switch switching according to claim 3, characterized in that, The full circuit power supply includes a power filtering module, which includes a first capacitor, a first inductor, a third capacitor, and a second inductor. The first capacitor and the first inductor are connected in series between the power supply terminals VCC and +3.3V-ALL of the inverter. The third capacitor and the second inductor are connected in series between the power supply terminals VCC and +3.3V-ALL of the D-type latch. This is used to suppress high-frequency noise and ripple on the power lines and ensure a stable power supply to the inverter and the D-type latch.

5. The protection circuit for radio frequency coaxial switch switching according to claim 1, characterized in that, The backlight control and protection module includes a signal filtering unit, which includes a fifth capacitor connected in parallel between the output terminal Q of the D-type latch and the output terminal of the backlight control and protection module to filter out high-frequency interference in the output signal.

6. The protection circuit for radio frequency coaxial switch switching according to claim 1, characterized in that, A second resistor is connected in series between the backlight control signal terminal and the data input terminal D of the D-type latch. The second resistor is used to limit the input current of the backlight control signal.

7. The protection circuit for radio frequency coaxial switch switching according to claim 6, characterized in that, A fourth capacitor is connected in parallel between the second resistor and the data input terminal D of the D-type latch. The other end of the fourth capacitor is connected to the circuit ground. The fourth capacitor is used to filter out high-frequency noise in the backlight control signal to ensure that the data signal input to the D-type latch is stable.

Images