A protection circuit, method and module of a radio frequency front-end circuit and a radio frequency device

Abstract

The application relates to the technical field of radio frequency circuit, and provides a protection circuit, a method, a module and a radio frequency device of a radio frequency front-end circuit, wherein the protection circuit comprises: a bidirectional power detection module which is connected in series in a link of a power amplifier to a radio frequency output end of the radio frequency front-end circuit; a comparison trigger module which is connected with the bidirectional power detection module; and a power control module which is connected with the comparison trigger module and the power amplifier. The bidirectional power detection module detects forward power and reverse power of the link, forms a first signal and a second signal, the comparison trigger module compares and processes the first signal and the second signal, generates a trigger signal when the output power is too large or the standing wave ratio is too large, and the power control module adjusts the output power of the power amplifier according to the trigger signal, so that negative effects of the too large output power or the too large standing wave ratio on circuit elements are avoided, the circuit elements are protected from damage, high-precision protection of the radio frequency front-end circuit is realized, and safety and reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of radio frequency circuit technology, and in particular to a protection circuit, method, module and radio frequency device for a radio frequency front-end circuit. Background Technology

[0002] The radio frequency (RF) front-end is a core component of modern wireless communication devices such as mobile phones, base stations, and routers. Its main function is to process and receive signals. RF front-end circuits typically include low-noise amplifiers, power amplifiers, band switches, and filters. The low-noise amplifier and power amplifier amplify the RF signal to a sufficiently high power to drive the antenna to radiate electromagnetic waves. The band switch and filter work together to control the switching of the RF signal between different frequency bands.

[0003] In the design and operation of RF front-end circuits, output power and VSWR are two crucial parameters that directly affect the system's performance, efficiency, stability, and even safety. Excessive output power can cause the power amplifier and back-end output network to experience excessive current and overheat, leading to performance degradation, shortened lifespan, or even device failure. Conversely, excessive VSWR significantly reduces RF efficiency, and the superposition of positive and negative power can cause circuit components to withstand excessive power, resulting in overload and damage. Therefore, both excessive output power and excessive VSWR pose a risk of device damage.

[0004] In existing technologies, output power is indirectly limited by restricting the operating current or voltage of the power amplifier to prevent excessive power consumption. However, this method is difficult to precisely limit the power and lacks solutions for situations with excessively high VSWR (Standing Wave Ratio). Therefore, effectively protecting the RF front-end from excessive output power and VSWR is a problem that urgently needs to be solved. Summary of the Invention

[0005] This invention provides a protection circuit, method, module, and RF device for radio frequency front-end circuits, which solves the defects in the prior art where radio frequency front-end circuits lack effective protection when the output power is too high and the VSWR is too high.

[0006] This invention provides a protection circuit for a radio frequency front-end circuit, comprising:

[0007] A bidirectional power detection module is connected in series in the link from the power amplifier to the RF output terminal of the RF front-end circuit. The bidirectional power detection module is used to detect the positive power signal of the link to form a first signal and to detect the reverse power signal of the link to form a second signal.

[0008] A comparison trigger module is connected to the bidirectional power detection module. The comparison trigger module is used to compare and process the first signal and the second signal to generate a trigger signal. The trigger signal indicates that the output power of the link is greater than a first threshold or the standing wave ratio is greater than a second threshold.

[0009] A power control module is connected to both the comparison trigger module and the power amplifier. The power control module is used to adjust the output power of the power amplifier according to the trigger signal.

[0010] According to the present invention, a protection circuit for a radio frequency front-end circuit is provided, wherein the comparison trigger module includes a first comparison trigger unit, a second comparison trigger unit, and a logic OR unit;

[0011] The first input terminal of the first comparison trigger unit is connected to the positive output terminal of the bidirectional power detection module to obtain the first signal, the second input terminal of the first comparison trigger unit is connected to the negative output terminal of the bidirectional power detection module to obtain the second signal, the third input terminal of the first comparison trigger unit is used to input the first threshold voltage signal, and the output terminal of the first comparison trigger unit is connected to the first input terminal of the logic OR unit.

[0012] The first input terminal of the second comparison trigger unit is connected to the positive output terminal of the bidirectional power detection module to obtain the first signal, the second input terminal of the second comparison trigger unit is connected to the negative output terminal of the bidirectional power detection module to obtain the second signal, the third input terminal of the second comparison trigger unit is used to input the second threshold voltage signal, and the output terminal of the second comparison trigger unit is connected to the second input terminal of the logic OR unit.

[0013] The output of the logic OR unit is connected to the power control module;

[0014] The first comparison triggering unit is used to generate a first triggering signal when the first signal, the second signal, and the first threshold voltage signal meet a first preset protection condition, and the second comparison triggering unit is used to generate a second triggering signal when the first signal, the second signal, and the second threshold voltage signal meet a second preset protection condition.

[0015] According to a protection circuit for a radio frequency front-end circuit provided by the present invention, the first comparison trigger unit includes a first proportional amplifier, a first comparator, a second comparator, and a first logic AND unit. The non-inverting input terminals of the first comparator and the second comparator are both connected to the positive output terminal of the bidirectional power detection module. The input terminal of the first proportional amplifier is connected to the inverting output terminal of the bidirectional power detection module. The output terminal of the first proportional amplifier is connected to the inverting input terminal of the first comparator. The inverting input terminal of the second comparator is used to input a first threshold voltage signal. The output terminal of the first comparator is connected to the first input terminal of the first logic AND unit. The output terminal of the second comparator is connected to the second input terminal of the first logic AND unit. The output terminal of the first logic AND unit is connected to the first input terminal of the logic OR unit.

[0016] According to a protection circuit for an RF front-end circuit provided by the present invention, the second comparison trigger unit includes a second proportional amplifier, a third comparator, a fourth comparator, and a second logic AND unit. The inverting input terminal of the third comparator is connected to the non-inverting output terminal of the bidirectional power detection module. The input terminal of the second proportional amplifier and the non-inverting input terminal of the fourth comparator are both connected to the inverting output terminal of the bidirectional power detection module. The output terminal of the second proportional amplifier is connected to the non-inverting input terminal of the third comparator. The inverting input terminal of the fourth comparator is used to input a second threshold voltage signal. The output terminal of the third comparator is connected to the first input terminal of the second logic AND unit. The output terminal of the fourth comparator is connected to the second input terminal of the second logic AND unit. The output terminal of the second logic AND unit is connected to the second input terminal of the logic OR unit.

[0017] According to a protection circuit for a radio frequency front-end circuit provided by the present invention, the bidirectional power detection module includes a coupler unit and a signal conversion unit. The coupler unit is connected in series in the link to detect the forward power signal and the reverse power signal of the link. The signal conversion unit is connected to the coupler unit and is used to convert the forward power signal into a DC signal as the first signal and convert the reverse power signal into a DC signal as the second signal.

[0018] According to a protection circuit for a radio frequency front-end circuit provided by the present invention, the coupler unit includes a first bidirectional coupler, the signal conversion unit includes a first forward power detection circuit and a first reverse power detection circuit, the main line of the first bidirectional coupler is connected in series in the link, the forward coupling end of the first bidirectional coupler is connected to the input end of the first forward power detection circuit, the reverse coupling end of the first bidirectional coupler is connected to the input end of the first reverse power detection circuit, and the output ends of the first forward power detection circuit and the first reverse power detection circuit are both connected to the comparison trigger module.

[0019] According to a protection circuit for an RF front-end circuit provided by the present invention, the coupler unit includes a positive unidirectional coupler and an anti-unidirectional coupler, the signal conversion unit includes a second positive power detection circuit and a second reverse power detection circuit, the main line of the positive unidirectional coupler and the main line of the anti-unidirectional coupler are connected in series to form a series circuit, the series circuit is connected in series in the link, the coupling end of the positive unidirectional coupler is connected to the input end of the second positive power detection circuit, the coupling end of the anti-unidirectional coupler is connected to the input end of the second reverse power detection circuit, and the output ends of the second positive power detection circuit and the second reverse power detection circuit are both connected to the comparison trigger module.

[0020] According to a protection circuit for a radio frequency front-end circuit provided by the present invention, the coupler unit includes a second bidirectional coupler and a first time-division switching unit, the signal conversion unit includes a bidirectional power detection circuit and a second time-division switching unit, the main line of the second bidirectional coupler is connected in series in the link, the first time-division input terminal of the first time-division switching unit is connected to the forward coupling terminal of the second bidirectional coupler, the second time-division input terminal of the first time-division switching unit is connected to the reverse coupling terminal of the second bidirectional coupler, the output terminal of the first time-division switching unit is connected to the input terminal of the bidirectional power detection circuit, the output terminal of the bidirectional power detection circuit is connected to the input terminal of the second time-division switching unit, the first time-division output terminal and the second time-division output terminal of the second time-division switching unit are both connected to the comparison trigger module, and the first time-division switching unit and the second time-division switching unit switch synchronously.

[0021] According to a protection circuit for a radio frequency front-end circuit provided by the present invention, the signal conversion unit includes at least one power detection circuit, the power detection circuit includes a DC blocking circuit, a subtraction circuit and a filtering and voltage regulation circuit, the input terminal of the DC blocking circuit is connected to the coupler unit, the output terminal of the DC blocking circuit is connected to the input terminal of the subtraction circuit, the output terminal of the subtraction circuit is connected to the input terminal of the filtering and voltage regulation circuit, and the output terminal of the filtering and voltage regulation circuit is connected to the comparison trigger module.

[0022] The DC blocking circuit is used to isolate the DC component of the input signal, and the subtraction circuit is used to subtract the input DC bias from the input signal.

[0023] According to the protection circuit of the radio frequency front-end circuit provided by the present invention, the power detection circuit further includes a current mirror circuit, the input terminal of the current mirror circuit is connected to the output terminal of the subtraction circuit, and the output terminal of the current mirror circuit is connected to the filter and voltage regulator circuit.

[0024] According to the present invention, a protection circuit for a radio frequency front-end circuit includes a DC blocking circuit comprising a DC blocking capacitor and a voltage divider circuit. One end of the DC blocking capacitor is connected to the coupler unit, one end of the voltage divider circuit is connected to the power supply terminal, the other end of the voltage divider circuit is grounded, and the other end of the DC blocking capacitor is connected to the midpoint of the voltage divider circuit and the input terminal of the subtraction circuit, respectively.

[0025] According to the present invention, a protection circuit for a radio frequency front-end circuit includes a subtraction circuit comprising a subtraction resistor, a subtraction capacitor, and a subtractor. The first input terminal of the subtractor is connected to the output terminal of the DC blocking circuit and one end of the subtraction resistor, respectively. The second input terminal of the subtractor is connected to the other end of the subtraction resistor and one end of the subtraction capacitor, respectively. The other end of the subtraction capacitor is grounded. The output terminal of the subtractor is connected to the input terminal of the current mirror circuit.

[0026] The present invention also provides a protection method for a radio frequency front-end circuit, which is implemented based on the above-described protection circuit for a radio frequency front-end circuit, the method comprising:

[0027] The forward power of the link is detected to form a first signal, and the reverse power in the link is detected to form a second signal;

[0028] The first signal and the second signal are compared and processed to generate a trigger signal, wherein the trigger signal indicates that the output power of the link is greater than a first threshold or the standing wave ratio is greater than a second threshold.

[0029] The output power of the power amplifier is adjusted according to the trigger signal.

[0030] According to a protection method for a radio frequency front-end circuit provided by the present invention, the step of comparing and processing the first signal and the second signal to generate a trigger signal includes:

[0031] The trigger signal is generated when it is determined that the voltage of the first signal is greater than a preset multiple of the voltage of the second signal and the voltage of the first signal is greater than a first threshold voltage.

[0032] Alternatively, the trigger signal is generated when it is determined that the voltage of the first signal is less than a preset multiple of the voltage of the second signal and the voltage of the second signal is greater than a second threshold voltage.

[0033] According to a protection method for a radio frequency front-end circuit provided by the present invention, adjusting the output power of the power amplifier according to the trigger signal includes:

[0034] According to the trigger signal, the bias current of the power amplifier is turned off and maintained for a preset time.

[0035] After the preset time, the bias current of the power amplifier is gradually increased to the preset bias current.

[0036] The present invention also provides a radio frequency front-end module, including a radio frequency front-end circuit and a protection circuit for the radio frequency front-end circuit described above.

[0037] According to a radio frequency front-end module provided by the present invention, the radio frequency front-end circuit includes a power amplifier, a switching module and a filter module, wherein the power amplifier, the bidirectional power detection module, the switching module and the filter module are connected in sequence, and the power control module is connected to the power amplifier.

[0038] The present invention also provides a radio frequency device, including a radio frequency front-end circuit and a protection circuit for the radio frequency front-end circuit described above.

[0039] This invention provides a protection circuit, method, module, and RF device for an RF front-end circuit, which at least achieves the following technical effects: A bidirectional power detection module is connected in series in the link from the power amplifier to the RF output of the RF front-end circuit to detect the forward power and reflected reverse power of the link, forming a first signal and a second signal respectively. The standing wave ratio (SWR) is determined by the forward and reverse power. The SWR state can be indirectly determined based on the relationship between the first and second signals. Simultaneously, the first and second signals can also characterize the output power, providing a basis for monitoring excessive output power and excessive SWR. A comparison trigger module compares the first and second signals to accurately generate a trigger signal when the output power exceeds a first threshold or the SWR exceeds a second threshold, i.e., when the output power or SWR is too high. Based on the trigger signal, the power control module reduces or shuts down the output power of the power amplifier. This avoids negative impacts on circuit components caused by excessive output power or excessive SWR, achieving the effect of protecting circuit components from damage. This facilitates high-precision protection of the RF front-end circuit, improving safety and reliability. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a structural block diagram of a protection circuit for a radio frequency front-end circuit provided by the present invention.

[0042] Figure 2 This is a structural block diagram of the comparison trigger module in one embodiment of the present invention.

[0043] Figure 3 This is a circuit diagram of a comparison trigger module in one embodiment of the present invention.

[0044] Figure 4 This is a circuit diagram of a bidirectional power detection module in one embodiment of the present invention.

[0045] Figure 5 This is a circuit diagram of a bidirectional power detection module in another embodiment of the present invention.

[0046] Figure 6 This is a circuit diagram of a bidirectional power detection module in another embodiment of the present invention.

[0047] Figure 7 This is a circuit diagram of a power detection circuit in one embodiment of the present invention.

[0048] Figure 8 This is a flowchart illustrating a protection method for a radio frequency front-end circuit provided by the present invention.

[0049] Figure 9 This is a timing diagram for controlling the bias current in one embodiment of the present invention.

[0050] Figure 10 This is a schematic diagram of the structure of a radio frequency front-end module provided by the present invention.

[0051] Figure label:

[0052] 100: Bidirectional power detection module; 110: Coupler unit; 111: First bidirectional coupler; 112: Positive unidirectional coupler; 113: Anti-unidirectional coupler; 114: Second bidirectional coupler; 115: First time-division switching unit; 120: Signal conversion unit; 121: First forward power detection circuit; 122: First reverse power detection circuit; 123: Second forward power detection circuit; 124: Second reverse power detection circuit; 125: Bidirectional power detection circuit; 126: Second time-division switching unit; 130: DC blocking circuit; 140: Subtraction circuit; 150: Filtering and voltage regulation circuit; 160: Current mirror circuit; 200: Comparison trigger module; 210: First comparison trigger unit; 211: First proportional amplifier; 212: First comparator; 213: Second comparator; 214: First logic AND unit; 220: Second comparison trigger unit; 221: Second proportional amplifier; 222: Third comparator; 223: Fourth comparator; 224: Second logic AND unit; 230: Logic OR unit; 300: Power control module; 410: Power amplifier; 420: Switching module; 430: Filter module; 440: Antenna. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0054] The following is combined Figures 1 to 7 A protection circuit for a radio frequency front-end circuit according to the present invention includes:

[0055] A bidirectional power detection module 100 is connected in series in the link from the power amplifier to the RF output terminal of the above-mentioned RF front-end circuit. The bidirectional power detection module 100 is used to detect the positive power signal of the link to form a first signal and to detect the reverse power signal of the link to form a second signal.

[0056] The comparison trigger module 200 is connected to the bidirectional power detection module 100. The comparison trigger module 200 is used to compare and process the first signal and the second signal to generate a trigger signal. The trigger signal indicates that the output power of the link is greater than the first threshold or the standing wave ratio is greater than the second threshold.

[0057] The power control module 300 is connected to the comparison trigger module 200 and the power amplifier respectively. The power control module 300 is used to adjust the output power of the power amplifier according to the trigger signal.

[0058] In the technical solution provided by this embodiment of the invention, a bidirectional power detection module 100 is connected in series in the link from the power amplifier to the RF output of the RF front-end circuit to detect the forward power signal and the reflected reverse power signal of the link, thereby forming a first signal and a second signal. Those skilled in the art will understand that the standing wave ratio (SWR) is determined by the forward and reverse power. Therefore, the SWR state can be indirectly determined based on the relationship between the first and second signals. Simultaneously, the first and second signals can also characterize the output power, providing a basis for monitoring excessive output power and excessive SWR. In this embodiment, the comparison trigger module 200 compares the first and second signals to accurately generate a trigger signal when the output power exceeds a first threshold or the SWR exceeds a second threshold, i.e., when the output power or SWR is excessive. Based on the trigger signal, the power control module 300 can adjust the output power of the power amplifier, i.e., reduce the output power of the power amplifier or directly turn off the power amplifier.

[0059] This avoids negative impacts on the circuit components in the RF front-end circuit due to excessive output power or VSWR, thus protecting the circuit components from damage. It also helps to achieve high-precision protection of the RF front-end circuit and improve safety and reliability.

[0060] refer to Figure 10 The RF front-end circuit includes a link from the power amplifier 410 to the RF output terminal, where the RF output terminal refers to the connection terminal with the antenna 440. Typically, in the RF front-end circuit, the filter is connected to the antenna 440, so the connection terminal between the filter and the antenna 440 can be considered the RF output terminal. A bidirectional power detection module 100 is connected in series in the above link, and can be connected between the output terminal of the power amplifier 410 and the input terminal of the filter. This allows for protection of each filter when there are filters in different frequency bands. In some embodiments, the bidirectional power detection module 100 can also be implemented by connecting the filter and the antenna 440.

[0061] It is understandable that when a trigger signal is generated, the power control module 300 adjusts the output power of the power amplifier, either by turning off the power amplifier or by reducing the output power of the power amplifier, in order to achieve a protection effect.

[0062] In some embodiments of the present invention, the power control module 300 may include a switching transistor and a delay capacitor. One end of the switching transistor is connected to one end of the delay capacitor and the bias terminal of the power amplifier, respectively. The other end of the switching transistor and the other end of the delay capacitor are grounded. The controlled end of the switching transistor is connected to the output terminal of the comparison trigger module 200. When the comparison trigger module 200 generates a trigger signal, the trigger signal turns on the switching transistor, making the bias terminal of the power amplifier equivalent to grounded, cutting off the bias current of the power amplifier, and thus cutting off the output power of the power amplifier to achieve a protection effect. After the trigger signal disappears, the switching transistor turns off, restoring power supply to the bias terminal of the power amplifier. Under the action of the delay capacitor, the delay capacitor absorbs energy and gradually increases the bias terminal voltage of the power amplifier, allowing the power amplifier to gradually restore its output power and preventing the output power from increasing too quickly and causing damage to the circuit components.

[0063] In some embodiments of the present invention, the power control module 300 may also be an implementation that includes a bias current control circuit or other circuit or device capable of adjusting the output power of the power amplifier.

[0064] refer to Figure 2 and Figure 3 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the comparison trigger module 200 includes a first comparison trigger unit 210, a second comparison trigger unit 220 and a logic OR unit 230.

[0065] The first input terminal of the first comparison trigger unit 210 is connected to the positive output terminal A of the bidirectional power detection module 100 to obtain a first signal, the second input terminal of the first comparison trigger unit 210 is connected to the inverted output terminal B of the bidirectional power detection module 100 to obtain a second signal, the third input terminal of the first comparison trigger unit 210 is used to input a first threshold voltage signal, and the output terminal of the first comparison trigger unit 210 is connected to the first input terminal of the logic OR unit 230.

[0066] The first input terminal of the second comparison trigger unit 220 is connected to the positive output terminal A of the bidirectional power detection module 100 to obtain a first signal, the second input terminal of the second comparison trigger unit 220 is connected to the negative output terminal B of the bidirectional power detection module 100 to obtain a second signal, the third input terminal of the second comparison trigger unit 220 is used to input a second threshold voltage signal, and the output terminal of the second comparison trigger unit 220 is connected to the second input terminal of the logic OR unit 230.

[0067] The output of logic OR unit 230 is connected to power control module 300;

[0068] The first comparison trigger unit 210 is used to generate a first trigger signal when the first signal, the second signal, and the first threshold voltage signal meet the first preset protection condition, and the second comparison trigger unit 220 is used to generate a second trigger signal when the first signal, the second signal, and the second threshold voltage signal meet the second preset protection condition.

[0069] During the operation of the aforementioned protection circuit, the first comparison trigger unit 210 acquires and compares the first signal, the second signal, and the first threshold voltage signal. When the comparison result meets the first preset protection condition, it means that the output power is greater than the first threshold, i.e., the output power is too high, and a first trigger signal is generated. The second comparison trigger unit 220 acquires and compares the first signal, the second signal, and the second threshold voltage. When the comparison result meets the second preset protection condition, it means that the standing wave ratio (VSWR) is greater than the second threshold, i.e., the VSWR is too high, and a second trigger signal is generated. The first trigger signal and the second trigger signal are processed by the logic OR unit 230 and then output. That is, the generation of either the first trigger signal or the second trigger signal will trigger the power control module 300 to adjust the output power of the power amplifier.

[0070] In this way, the two protection scenarios of excessive output power and excessive VSWR are triggered by comparison using the first comparison trigger unit 210 and the second comparison trigger unit 220, respectively. This isolates the two scenarios, improving the accuracy of the judgment. Furthermore, the trigger thresholds for excessive output power and excessive VSWR can be independently and flexibly adjusted by regulating the first and second threshold voltages, thus meeting different application requirements. Additionally, the division of the first and second comparison trigger units 210 into single functions reduces circuit complexity.

[0071] It should be noted that the first trigger signal and the second trigger signal are processed by the logic OR unit 230 before being output. Based on the output logic of the logic OR unit 230, the logic OR unit 230 will output a trigger signal when either the first trigger signal or the second trigger signal is generated. Alternatively, from another perspective, both the first trigger signal and the second trigger signal can enable the power control module 300 to adjust the output power of the power amplifier.

[0072] In some embodiments of the present invention, the first preset protection condition is: the voltage V of the first signal. A The voltage V of the second signal is greater than a preset multiple B And the voltage V of the first signal A Voltage signal V greater than the first threshold limit1 V A >kV B And V A >V limit1The second preset protection condition is: the voltage V of the first signal. A The voltage V of the second signal is less than a preset multiple B And the voltage V of the second signal B The voltage signal V is greater than the second threshold voltage signal limit2 V A <kV B And V B >V limit2 Where k is a preset multiple.

[0073] Since accurate determination of the standing wave ratio (SWR) requires determining the ratio of reverse power to forward power, the specific calculation formula is: SWR = (1 + Γ) / (1 – Γ), and the reflection coefficient... , where P F Forward power; P R This represents the reflected power. Implementing division and square root operations using circuit hardware requires a complex circuit structure.

[0074] In response, based on the relationship between the magnitudes of forward power and reverse power and the standing wave ratio, and the correspondence between the first signal and the forward power, and the second signal and the reverse power, the protection conditions of the above embodiments are used to limit the voltage V of the first signal. A The voltage V of the second signal is greater than a preset multiple B Comparison, that is, comparison and judgment of V A <kV B This is equivalent to determining 1 / k <V B / V A Whether this holds true can indirectly determine the ratio of reverse power to forward power, based on V. B / V A A positive correlation exists between the standing wave ratio (SWR) and the voltage V of the first signal, which can be used to indirectly determine the SWR. A The voltage V of the second signal at a preset multiple B This comparison method cleverly determines the Standing Wave Ratio (SWR) without requiring division or square root operations, thus simplifying circuit design. In V A <kV B When the VSWR is greater than the second threshold, i.e., the VSWR is too high, in order to avoid the reverse power fluctuation from falsely triggering the protection due to interference or other reasons when the output power is low, the protection is set at V. A <kV B V needs to be satisfied simultaneously B >V limit2 Only when protection is triggered will the accuracy and reliability of the protection be improved.

[0075] Understandably, V A >kV BThis means the VSWR is normal. At this point, it's necessary to check if the output power is too high. Since forward power is positively correlated with output power, therefore, at V... A >kV B Under the condition that V is satisfied at the same time A >V limit1 If the output power exceeds the first threshold, it can be considered that the output power is too high, thus triggering the protection.

[0076] refer to Figure 3 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the first comparison trigger unit 210 includes a first proportional amplifier 211, a first comparator 212, a second comparator 213, and a first logic AND unit 214. The non-inverting input terminal of the first comparator 212 and the non-inverting input terminal of the second comparator 213 are both connected to the positive output terminal A of the bidirectional power detection module 100. The input terminal of the first proportional amplifier 211 is connected to the inverting output terminal B of the bidirectional power detection module 100. The output terminal of the first proportional amplifier 211 is connected to the inverting input terminal of the first comparator 212. The inverting input terminal of the second comparator 213 is used to input a first threshold voltage signal. The output terminal of the first comparator 212 is connected to the first input terminal of the first logic AND unit 214. The output terminal of the second comparator 213 is connected to the second input terminal of the first logic AND unit 214. The output terminal of the first logic AND unit 214 is connected to the first input terminal of the logic OR unit 230.

[0077] In this embodiment, the first proportional amplifier 211 is connected to the inverting output terminal B of the bidirectional power detection module 100 to obtain the second signal and amplify it proportionally to form a voltage of the second signal with a preset multiple, i.e., kV. B .

[0078] The non-inverting input of the first comparator 212 is connected to the positive output A of the bidirectional power detection module 100 to obtain the voltage V of the first signal. A Meanwhile, the inverting input of the first comparator 212 is connected to the output of the first proportional amplifier 211 to obtain the voltage kV of the second signal at a preset multiple. B The first comparator 212 will convert V A With kV B In comparison, in V A >kV B When the output is high, it outputs a high level; otherwise, it outputs a low level.

[0079] The non-inverting input of the second comparator 213 is connected to the positive output A of the bidirectional power detection module 100 to obtain the voltage V of the first signal. A The inverting input of the second comparator 213 acquires the voltage V of the first threshold voltage signal. limit1The second comparator 213 will V A With V limit1 In comparison, in V A >V limit1 When the output is high, it outputs a high level; otherwise, it outputs a low level.

[0080] The first logic AND unit 214 is connected to the output of the first comparator 212 and the output of the second comparator 213, respectively. Both the first comparator 212 and the second comparator 213 output a high level, i.e., V. A >kV B And V A >V limit1 When the first logic AND unit 214 outputs a high level, that is, the first trigger signal is sent to the logic OR unit 230.

[0081] In this way, the first preset protection condition is determined through hardware, that is, whether the output power is too high. No program processing is required, that is, no reliance on processors or other devices is needed. This is beneficial to improve the response speed of protection, improve the stability of protection, and reduce implementation costs.

[0082] refer to Figure 3 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the second comparison trigger unit 220 includes a second proportional amplifier 221, a third comparator 222, a fourth comparator 223, and a second logic AND unit 224. The inverting input terminal of the third comparator 222 is connected to the positive output terminal A of the bidirectional power detection module 100. The input terminal of the second proportional amplifier 221 and the non-inverting input terminal of the fourth comparator 223 are both connected to the inverting output terminal B of the bidirectional power detection module 100. The output terminal of the second proportional amplifier 221 is connected to the non-inverting input terminal of the third comparator 222. The inverting input terminal of the fourth comparator 223 is used to input a second threshold voltage signal. The output terminal of the third comparator 222 is connected to the first input terminal of the second logic AND unit 224. The output terminal of the fourth comparator 223 is connected to the second input terminal of the second logic AND unit 224. The output terminal of the second logic AND unit 224 is connected to the second input terminal of the logic OR unit 230.

[0083] In this embodiment, the second proportional amplifier 221 is connected to the inverting output terminal B of the bidirectional power detection module 100 to obtain the second signal and amplify it proportionally to form a voltage of the second signal with a preset multiple, i.e., kV. B .

[0084] The non-inverting input of the third comparator 222 is connected to the output of the second proportional amplifier 221 to obtain the voltage kV of the second signal at a preset multiple. B The inverting input of the third comparator 222 is connected to the positive output A of the bidirectional power detection module 100 to obtain the voltage V of the first signal.A The third comparator 222 will V A With kV B In comparison, in V A <kV B When the output is high, it outputs a high level; otherwise, it outputs a low level.

[0085] The non-inverting input of the fourth comparator 223 is connected to the inverting output B of the bidirectional power detection module 100 to obtain the voltage V of the second signal. B The inverting input of the fourth comparator 223 acquires the voltage V of the second threshold voltage signal. limit2 The second comparator 213 will V B With V limit2 In comparison, in V B >V limit2 When the output is high, it outputs a high level; otherwise, it outputs a low level.

[0086] The second logic AND unit 224 is connected to the outputs of the third comparator 222 and the fourth comparator 223, respectively. When both the third comparator 222 and the fourth comparator 223 output a high level, i.e., V... A <kV B And V B >V limit2 When the second logic AND unit 224 outputs a high level, that is, the second trigger signal is sent to the logic OR unit 230.

[0087] In this way, the second preset protection condition is determined through hardware, that is, whether the VSWR is too high. No program processing is required, that is, no reliance on processors or other devices is needed. This is beneficial to improve the response speed of protection, improve the stability of protection, and reduce implementation costs.

[0088] In some embodiments of the present invention, the logic OR unit 230 may include implementations of circuits or devices such as OR gate circuits and OR gate chips that implement the logic OR function, and the first logic AND unit 214 and the second logic AND unit 224 may include implementations of circuits or devices such as AND gate circuits and AND gate chips that implement the logic AND function.

[0089] In some embodiments of the present invention, the comparison trigger module 200 may also include a device with processing function such as a processor to determine whether there is a situation where the output power is greater than the first threshold or the standing wave ratio is greater than the second threshold through program processing, thereby controlling the generation of the trigger signal.

[0090] refer to Figures 4 to 6In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the bidirectional power detection module 100 includes a coupler unit 110 and a signal conversion unit 120. The coupler unit 110 is connected in series in the link to detect the forward power signal and the reverse power signal of the link. The signal conversion unit 120 is connected to the coupler unit 110 and is used to convert the forward power signal into a DC signal as a first signal and convert the reverse power signal into a DC signal as a second signal.

[0091] In the above embodiment, the forward power signal and the reverse power signal are detected by coupling through the coupler unit 110. Since the forward and reverse power signals of the radio frequency are alternating signals, the signal conversion unit 120 converts the forward power signal and the reverse power signal into DC signals respectively to facilitate subsequent comparison processing, forming corresponding first signals and second signals. In this way, by detecting the first and second signals through non-intrusive coupling, it is beneficial to maintain the integrity of the radio frequency link, avoid problems such as impedance matching of the radio frequency link, and has the advantage of low loss.

[0092] refer to Figure 4 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the coupler unit 110 includes a first bidirectional coupler 111, the signal conversion unit 120 includes a first forward power detection circuit 121 and a first reverse power detection circuit 122, the main line of the first bidirectional coupler 111 is connected in series in the link, the forward coupling end of the first bidirectional coupler 111 is connected to the input end of the first forward power detection circuit 121, the reverse coupling end of the first bidirectional coupler 111 is connected to the input end of the first reverse power detection circuit 122, and the output ends of the first forward power detection circuit 121 and the first reverse power detection circuit 122 are both connected to the comparison trigger module 200.

[0093] In one embodiment of the coupler unit 110, a first bidirectional coupler 111 is used, with its main line connected in series with the RF link and its main line coupled to a branch line. The two ends of the branch line serve as the forward coupling end and the reverse coupling end, respectively generating a forward power signal and a reverse power signal. A first forward power detection circuit 121 is connected to the forward coupling end to acquire the forward power signal and convert it into a first signal. A first reverse power detection circuit 122 is connected to the reverse coupling end to acquire the reverse power signal and convert it into a second signal. Thus, through a bidirectional coupler and two power detection circuits, the forward and reverse power of the RF link are detected, forming the first and second signals.

[0094] refer to Figure 5In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the coupler unit 110 includes a positive unidirectional coupler 112 and an anti-unidirectional coupler 113, and the signal conversion unit 120 includes a second positive power detection circuit 123 and a second reverse power detection circuit 124. The main line of the positive unidirectional coupler 112 and the main line of the anti-unidirectional coupler 113 are connected in series to form a series circuit. The series circuit is connected in series in the link. The coupling end of the positive unidirectional coupler 112 is connected to the input end of the second positive power detection circuit 123, and the coupling end of the anti-unidirectional coupler 113 is connected to the input end of the second reverse power detection circuit 124. The output ends of the second positive power detection circuit 123 and the second reverse power detection circuit 124 are both connected to the comparison trigger module 200.

[0095] As another embodiment of the coupler unit 110, a positive unidirectional coupler 112 and an anti-unidirectional coupler 113 are used. Their main lines are connected in series in the RF link. In the positive unidirectional coupler 112, the main line is coupled to the branch line and generates a positive power signal at the coupling end of the branch line. In the anti-unidirectional coupler 113, the main line is coupled to the branch line and generates a reverse power signal at the coupling end of the branch line. A second positive power detection circuit 123 is connected to the coupling end of the positive unidirectional coupler 112 to acquire the positive power signal and convert it into a first signal. A first reverse power detection circuit 122 is connected to the reverse coupling end to acquire the reverse power signal and convert it into a second signal. Thus, two unidirectional couplers are used to detect the positive and reverse power respectively. Since the positive and reverse power are detected separately, mutual interference is avoided, resulting in higher detection accuracy. Combining the two power detection circuits to generate the first and second signals respectively improves the accuracy of protection against excessive output power and excessive VSWR.

[0096] refer to Figure 6 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the coupler unit 110 includes a second bidirectional coupler 114 and a first time-division switching unit 115, and the signal conversion unit 120 includes a bidirectional power detection circuit 125 and a second time-division switching unit 126. The main line of the second bidirectional coupler 114 is connected in series in the link. The first time-division input terminal of the first time-division switching unit 115 is connected to the forward coupling terminal of the second bidirectional coupler 114, and the second time-division input terminal of the first time-division switching unit 115 is connected to the reverse coupling terminal of the second bidirectional coupler 114. The output terminal of the first time-division switching unit 115 is connected to the input terminal of the bidirectional power detection circuit 125, and the output terminal of the bidirectional power detection circuit 125 is connected to the input terminal of the second time-division switching unit 126. The first time-division output terminal and the second time-division output terminal of the second time-division switching unit 126 are both connected to the comparison trigger module 200. The first time-division switching unit 115 and the second time-division switching unit 126 switch synchronously.

[0097] In another embodiment of the coupler unit 110, a second bidirectional coupler 114 is used, with its main line connected in series with the RF link and coupled to a branch line. The two ends of the branch line serve as the forward coupling end and the reverse coupling end, respectively generating a forward power signal and a reverse power signal. A first time-division switching unit 115 is connected to both the forward and reverse coupling ends to output the forward and reverse power signals to the bidirectional power detection circuit 125 in a time-division manner. The bidirectional power detection circuit 125 acquires the forward and reverse power signals and converts them into a first signal and a second signal, respectively. A second time-division switching unit 126 is connected to the output of the bidirectional power detection circuit 125 to output the first and second signals through different output terminals in a time-division manner. Thus, based on a bidirectional coupler and a power detection circuit, and in conjunction with two time-division switches, the power detection circuit is time-division multiplexed to form the first and second signals, sharing a single power detection circuit. This reduces the number of power detection circuits and saves the area occupied by power detection in the circuit.

[0098] The first time-division switching unit 115 and the second time-division switching unit 126 switch synchronously, such that when the first time-division switching unit 115 transmits a positive power signal to the bidirectional power detection circuit 125, the second time-division switching unit 126 outputs a first signal through its first output terminal; when the first time-division switching unit 115 transmits a reverse power signal to the bidirectional power detection circuit 125, the second time-division switching unit 126 outputs a second signal through its second output terminal. That is, the first output terminal of the second time-division switching unit 126 always outputs the first signal, and the second output terminal always outputs the second signal. In some embodiments, both the first and second output terminals of the second time-division switching unit 126 are connected to filter capacitors to retain the voltages of the first and second signals during time-division switching, utilizing the capacitor's characteristics for comparison and triggering module 200 to process. In some embodiments, the voltages of the first and second signals can also be retained during time-division switching through registers or other means.

[0099] In some embodiments of the present invention, the first time-division switching unit 115 and the second time-division switching unit 126 may include implementations of devices such as single-pole double-throw switches and radio frequency switch chips to realize the function of time-division switching.

[0100] refer to Figure 7In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the signal conversion unit 120 includes at least one power detection circuit. The power detection circuit includes a DC blocking circuit 130, a subtraction circuit 140, and a filter and voltage regulation circuit 150. The input terminal of the DC blocking circuit 130 is connected to the coupler unit 110, the output terminal of the DC blocking circuit 130 is connected to the input terminal of the subtraction circuit 140, the output terminal of the subtraction circuit 140 is connected to the input terminal of the filter and voltage regulation circuit 150, and the output terminal of the filter and voltage regulation circuit 150 is connected to the comparison trigger module 200.

[0101] The DC blocking circuit 130 is used to isolate the DC component of the input signal, and the subtraction circuit 140 is used to subtract the input DC bias from the input signal.

[0102] In the above embodiment, the input terminal of the DC blocking circuit 130 acquires a positive power signal or a reverse power signal, isolates the DC components in the positive power signal and the reverse power signal, and then the subtraction circuit 140 subtracts its own DC bias from the positive power signal and the reverse power signal after DC blocking, and then converts them into a DC current signal output. The DC current signal represents the power of the input positive power signal and the reverse power signal. The DC current signal is filtered and regulated by the filter and voltage regulator circuit 150 to form a stable voltage signal output, which corresponds to the formation of the first signal or the second signal.

[0103] Therefore, for alternating forward and reverse power signals, the DC component is removed through two stages of DC blocking and subtraction, and then converted into a DC current signal. The DC current signal is then filtered and regulated to convert into a corresponding DC voltage signal to obtain the first or second signal. This avoids the influence of the DC component and helps the first signal to more accurately represent the magnitude of the forward power and the second signal to more accurately represent the magnitude of the reverse power, thereby improving the accuracy of the final protection.

[0104] refer to Figure 7 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the power detection circuit further includes a current mirror circuit 160, the input terminal of the current mirror circuit 160 is connected to the output terminal of the subtraction circuit 140, and the output terminal of the current mirror circuit 160 is connected to the filter and voltage regulator circuit 150.

[0105] In the above embodiment, the DC current signal output by the subtraction circuit 140 is transmitted to the current mirror circuit 160. The current mirror circuit 160 replicates and amplifies the DC current signal before transmitting it to the filter and voltage regulator circuit 150 to convert it into a DC voltage signal. Utilizing the high output impedance of the current mirror circuit 160, the influence of subsequent connected loads on the subtraction circuit 140 is reduced, making the DC current signal output by the subtraction circuit 140 more accurate. Simultaneously, the current mirror circuit 160 amplifies the DC current signal, resulting in higher resolution after conversion to DC, which helps improve the accuracy of trigger protection.

[0106] refer to Figure 7 In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the DC blocking circuit 130 includes a DC blocking capacitor and a voltage divider circuit. One end of the DC blocking capacitor is connected to the coupler unit 110, one end of the voltage divider circuit is connected to the power supply terminal, the other end of the voltage divider circuit is grounded, and the other end of the DC blocking capacitor is connected to the midpoint of the voltage divider circuit and the input terminal of the subtraction circuit 140, respectively.

[0107] In the above embodiments, the input signal is DC isolated by a DC blocking capacitor, which is simple in structure and easy to implement. Then, a voltage divider circuit is used to raise the potential of the DC-isolated signal to form an intermediate signal V. RF intermediate signal V RF The voltage fluctuation is kept within a suitable voltage range, which facilitates the subsequent subtraction circuit 140 to perform subtraction operations and avoids intermediate signal V. RF If the voltage is too low or negative, it ensures that the subtraction circuit 140 performs the subtraction correctly, which helps improve the reliability of the circuit.

[0108] It is understandable that the intermediate signal V RF This includes the AC component of the input power signal, the residual DC component after being filtered by the DC blocking capacitor, and the potential raised by the voltage divider circuit. The potential raised by the voltage divider circuit is a DC component; therefore, the residual DC component after being filtered by the DC blocking capacitor and the potential component raised by the voltage divider circuit together form the DC bias of the AC component. After processing by the subtraction circuit 140, the intermediate signal V is removed. RF The DC bias includes the potential raised by the voltage divider circuit, so the voltage divider circuit will not affect the accuracy of power detection.

[0109] refer to Figure 7In some embodiments of the protection circuit of the radio frequency front-end circuit of the present invention, the subtraction circuit 140 includes a subtraction resistor, a subtraction capacitor and a subtractor. The first input terminal of the subtractor is connected to the output terminal of the DC blocking circuit 130 and one end of the subtraction resistor, respectively. The second input terminal of the subtractor is connected to the other end of the subtraction resistor and one end of the subtraction capacitor, respectively. The other end of the subtraction capacitor is grounded. The output terminal of the subtractor is connected to the input terminal of the current mirror circuit 160.

[0110] In the above embodiment, the intermediate signal V is obtained after DC blocking processing. RF intermediate signal V RF The signal is transmitted to the first input of the subtractor, and the intermediate signal V is simultaneously transmitted. RF The DC bias V is obtained after filtering by a subtraction resistor and a subtraction capacitor. DC The input is given to the second input terminal of the subtractor, and the subtractor converts the intermediate signal V... RF With DC bias V DC The subtraction is performed, and a corresponding DC current signal is output based on the subtraction result. The DC current signal represents the power of the input positive and negative power signals. The DC current signal output by the subtractor is transmitted to the current mirror circuit 160. Thus, through the structure of the subtraction resistor, subtraction capacitor, and subtractor, the intermediate signal V is converted into a DC current signal. RF Subtract its own DC bias V DC It acquires a DC current signal that represents the power level. The structure is simple and reliable, and it does not rely on processors or other devices. This is beneficial for improving the response speed of protection, improving the stability of protection, and reducing implementation costs.

[0111] The present invention provides a method for protecting a radio frequency front-end circuit. The method described below can be referred to in correspondence with the protection circuit described above.

[0112] refer to Figure 8 The present invention also provides a protection method for a radio frequency front-end circuit, which is implemented based on the above-mentioned protection circuit for a radio frequency front-end circuit, and the method includes:

[0113] S110, Detect the positive power signal of the link to form a first signal, and detect the reverse power signal in the link to form a second signal;

[0114] S120. The first signal and the second signal are compared and processed to generate a trigger signal. The trigger signal indicates that the output power of the link is greater than the first threshold or the standing wave ratio is greater than the second threshold.

[0115] S130. Adjust the output power of the power amplifier according to the trigger signal.

[0116] In the above embodiment, the bidirectional power detection module 100 detects the forward power signal and the reflected reverse power signal of the link, forming a first signal and a second signal accordingly. The standing wave ratio (SWR) is determined by the forward and reverse power. The SWR state can be indirectly determined based on the relationship between the first and second signals. Simultaneously, the first and second signals can also characterize the output power, providing a basis for monitoring excessive output power and excessive SWR. The comparison trigger module 200 compares the first and second signals to accurately generate a trigger signal when the output power exceeds a first threshold or the SWR exceeds a second threshold, i.e., when the output power or SWR is excessive. Based on the trigger signal, the power control module 300 reduces or shuts off the output power of the power amplifier.

[0117] This avoids negative impacts on circuit components due to excessive output power or high VSWR, thus protecting circuit components from damage and enabling high-precision protection of RF front-end circuits, improving safety and reliability.

[0118] In some embodiments of a protection method for a radio frequency front-end circuit according to the present invention, S120 includes:

[0119] A trigger signal is generated when the voltage of the first signal is determined to be greater than the voltage of the second signal by a preset multiple and the voltage of the first signal is greater than the first threshold voltage.

[0120] Alternatively, a trigger signal is generated when it is determined that the voltage of the first signal is less than a preset multiple of the voltage of the second signal and the voltage of the second signal is greater than a second threshold voltage.

[0121] In the above embodiment, the voltage V of the first signal is... A With the voltage V of the second signal B Comparison:

[0122] The voltage V of the first signal A The voltage V of the second signal is greater than a preset multiple B And the voltage V of the first signal A Voltage signal V greater than the first threshold limit1 V A >kV B And V A >V limit1 When this happens, it means the output power is too high, generating a trigger signal;

[0123] The voltage V of the first signal A The voltage V of the second signal is less than a preset multiple B And the voltage V of the second signal B The voltage signal V is greater than the second threshold voltage signal limit2 V A <kVB And V B >V limit2 When this occurs, it means the standing wave ratio is too high, generating a trigger signal.

[0124] Therefore, it can accurately trigger protection in cases of excessive output power and excessive VSWR, achieving high-precision protection for the RF front-end circuit. At the same time, it can determine whether there is excessive output power and excessive VSWR simply by comparison, without the need to calculate the specific VSWR value, which helps to simplify the process and improve the response efficiency of the trigger protection.

[0125] refer to Figure 9 In some embodiments of a protection method for a radio frequency front-end circuit according to the present invention, S130 includes:

[0126] Based on the trigger signal, the bias current of the power amplifier is turned off and remains off for a preset time.

[0127] After a preset time, the bias current of the control power amplifier is gradually increased to the preset bias current.

[0128] In the above embodiment, the power control module 300 responds to the trigger signal by turning off the bias current of the power amplifier, thereby turning off the output power of the power amplifier as well. This prevents excessive output power and high VSWR from damaging circuit components, achieving a protection effect for the RF front-end circuit. After the power control module 300 controls the bias current of the power amplifier to turn off, it maintains this position for a preset time t1, and then gradually increases the bias current of the power amplifier to the preset bias current. Maintaining the preset time t1 allows sufficient time for the devices in the RF front-end circuit to reset their operating state, facilitating the return of the RF front-end circuit to normal operation. Simultaneously, gradually increasing the bias current allows the output power of the power amplifier to gradually increase, preventing a rapid increase in output power from causing instantaneous high-power damage to circuit components, thus improving safety and reliability.

[0129] It should be emphasized that as the bias current of the power amplifier is gradually increased by the power control module 300, a trigger signal can also be generated. That is, if the output power or VSWR is too high during the process of gradually increasing the bias current of the power amplifier, the protection will be triggered, causing the power amplifier current to be turned off again.

[0130] In some embodiments of the present invention, the power control module 300 controls the bias current of the power amplifier to gradually increase, which can be controlled in a way that follows a preset slope. That is, the bias current of the power amplifier is gradually increased according to a preset slope until it reaches the preset bias current. In this way, the bias current of the power amplifier can be controlled to recover to the preset bias current within time t2, where time t2 is related to the slope.

[0131] refer to Figure 10 The present invention also provides a radio frequency front-end module, including a radio frequency front-end circuit and a protection circuit for the radio frequency front-end circuit described above.

[0132] In the RF front-end module, a bidirectional power detection module 100 is connected in series in the link from the power amplifier to the RF output of the RF front-end circuit to detect the forward power signal and the reflected reverse power signal of the link, thereby forming a first signal and a second signal. A comparison trigger module 200 compares the first signal and the second signal to accurately generate a trigger signal when the output power exceeds a first threshold or the VSWR exceeds a second threshold, i.e., when the output power or VSWR is too high. Based on the trigger signal, the power control module 300 reduces or shuts off the output power of the power amplifier.

[0133] This avoids negative impacts on circuit components due to excessive output power or high VSWR, thus protecting circuit components from damage and enabling high-precision protection of RF front-end circuits, improving safety and reliability.

[0134] In some embodiments of the present invention, the radio frequency front-end module may be an L-PAMiD module.

[0135] refer to Figure 10 In some embodiments of the radio frequency front-end module of the present invention, the radio frequency front-end circuit includes a power amplifier 410, a switching module 420 and a filter module 430. The power amplifier 410, the bidirectional power detection module 100, the switching module 420 and the filter module 430 are connected in sequence, and the power control module 300 is connected to the power amplifier 410.

[0136] In the above embodiments, by connecting the bidirectional power detection module 100 between the output terminal of the power amplifier 410 and the switching module 420, the power detection point is made close to the output terminal of the power amplifier 410, which is beneficial for accurately detecting the magnitude of the original output power and improving the accuracy of power detection. At the same time, the bidirectional power detection module 100 is located between the power amplifier 410 and the filter module 430, so that when the filter module 430 includes filters of multiple frequency bands, the bidirectional power detection module 100 can also protect the filters of each frequency band, which is beneficial for improving the safety and reliability of protection.

[0137] Understandably, the filter module 430 is used to connect to the antenna 440 to transmit radio frequency signals to the antenna 440.

[0138] In some embodiments of the present invention, the radio frequency front-end circuit may include two power amplifiers 410 cascaded together, and the power control module 300 is connected to the two power amplifiers 410. A single power amplifier 410 may not simultaneously meet the requirements of high gain, high efficiency, and high output power. Therefore, a structure using two cascaded power amplifiers 410 is employed. The pre-amplifier 410 can be a high-gain power amplifier to amplify the input radio frequency signal to a sufficiently high voltage, while the post-amplifier 410 employs a high-efficiency and high-output-power power amplifier to meet the required output power.

[0139] The filter module 430 includes filters corresponding to multiple frequency bands. By connecting to filters of different frequency bands through the switching module 420, radio frequency output of different frequency bands can be realized.

[0140] The present invention also provides a radio frequency device, including a radio frequency front-end circuit and a protection circuit for the radio frequency front-end circuit described above.

[0141] The radio frequency device of the present invention can be a signal base station, a mobile phone, or other device with radio frequency function.

[0142] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0143] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0144] 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.

Claims

1. A protection circuit for a radio frequency front-end circuit, characterized in that, include: A bidirectional power detection module (100) is connected in series in the link from the power amplifier to the RF output terminal of the RF front-end circuit. The bidirectional power detection module (100) is used to detect the positive power signal of the link to form a first signal and to detect the reverse power signal of the link to form a second signal. A comparison trigger module (200) is connected to the bidirectional power detection module (100). The comparison trigger module (200) is used to compare and process the first signal and the second signal to generate a trigger signal. The trigger signal indicates that the output power of the link is greater than a first threshold or the standing wave ratio is greater than a second threshold. A power control module (300) is connected to the comparison trigger module (200) and the power amplifier respectively. The power control module (300) is used to adjust the output power of the power amplifier according to the trigger signal. The comparison trigger module (200) includes a first comparison trigger unit (210), a second comparison trigger unit (220), and a logic OR unit (230). The first input terminal of the first comparison trigger unit (210) is connected to the positive output terminal of the bidirectional power detection module (100) to obtain the first signal, the second input terminal of the first comparison trigger unit (210) is connected to the negative output terminal of the bidirectional power detection module (100) to obtain the second signal, the third input terminal of the first comparison trigger unit (210) is used to input the first threshold voltage signal, and the output terminal of the first comparison trigger unit (210) is connected to the first input terminal of the logic OR unit (230). The first input terminal of the second comparison trigger unit (220) is connected to the positive output terminal of the bidirectional power detection module (100) to obtain the first signal, the second input terminal of the second comparison trigger unit (220) is connected to the negative output terminal of the bidirectional power detection module (100) to obtain the second signal, the third input terminal of the second comparison trigger unit (220) is used to input the second threshold voltage signal, and the output terminal of the second comparison trigger unit (220) is connected to the second input terminal of the logic OR unit (230). The output of the logic OR unit (230) is connected to the power control module (300); The first comparison trigger unit (210) is used to generate a first trigger signal when the voltage of the first signal is greater than a preset multiple of the voltage of the second signal and the voltage of the first signal is greater than the voltage of the first threshold voltage signal. The second comparison trigger unit (220) is used to generate a second trigger signal when the voltage of the first signal is less than a preset multiple of the voltage of the second signal and the voltage of the second signal is greater than the voltage of the second threshold voltage signal.

2. The protection circuit for a radio frequency front-end circuit according to claim 1, characterized in that, The first comparison trigger unit (210) includes a first proportional amplifier (211), a first comparator (212), a second comparator (213), and a first logic AND unit (214). The non-inverting input of the first comparator (212) and the non-inverting input of the second comparator (213) are both connected to the positive output of the bidirectional power detection module (100). The input of the first proportional amplifier (211) is connected to the inverting output of the bidirectional power detection module (100). The output of the first proportional amplifier (211) is connected to the inverting input of the first comparator (212). The inverting input of the second comparator (213) is used to input a first threshold voltage signal. The output of the first comparator (212) is connected to the first input of the first logic AND unit (214). The output of the second comparator (213) is connected to the second input of the first logic AND unit (214). The output of the first logic AND unit (214) is connected to the first input of the logic OR unit (230).

3. The protection circuit for a radio frequency front-end circuit according to claim 1, characterized in that, The second comparison trigger unit (220) includes a second proportional amplifier (221), a third comparator (222), a fourth comparator (223), and a second logic AND unit (224). The inverting input of the third comparator (222) is connected to the non-inverting output of the bidirectional power detection module (100). The input of the second proportional amplifier (221) and the non-inverting input of the fourth comparator (223) are both connected to the inverting output of the bidirectional power detection module (100). The output terminal of (221) is connected to the non-inverting input terminal of the third comparator (222), the inverting input terminal of the fourth comparator (223) is used to input the second threshold voltage signal, the output terminal of the third comparator (222) is connected to the first input terminal of the second logic AND unit (224), the output terminal of the fourth comparator (223) is connected to the second input terminal of the second logic AND unit (224), and the output terminal of the second logic AND unit (224) is connected to the second input terminal of the logic OR unit (230).

4. The protection circuit for a radio frequency front-end circuit according to claim 1, characterized in that, The bidirectional power detection module (100) includes a coupler unit (110) and a signal conversion unit (120). The coupler unit (110) is connected in series in the link to detect the forward power signal and the reverse power signal of the link. The signal conversion unit (120) is connected to the coupler unit (110) and is used to convert the forward power signal into a DC signal as the first signal and convert the reverse power signal into a DC signal as the second signal.

5. The protection circuit for a radio frequency front-end circuit according to claim 4, characterized in that, The coupler unit (110) includes a first bidirectional coupler (111), and the signal conversion unit (120) includes a first forward power detection circuit (121) and a first reverse power detection circuit (122). The main line of the first bidirectional coupler (111) is connected in series in the link. The forward coupling end of the first bidirectional coupler (111) is connected to the input end of the first forward power detection circuit (121), and the reverse coupling end of the first bidirectional coupler (111) is connected to the input end of the first reverse power detection circuit (122). The output ends of the first forward power detection circuit (121) and the first reverse power detection circuit (122) are both connected to the comparison trigger module (200).

6. The protection circuit for a radio frequency front-end circuit according to claim 4, characterized in that, The coupler unit (110) includes a positive unidirectional coupler (112) and an anti-unidirectional coupler (113). The signal conversion unit (120) includes a second positive power detection circuit (123) and a second reverse power detection circuit (124). The main line of the positive unidirectional coupler (112) and the main line of the anti-unidirectional coupler (113) are connected in series to form a series circuit. The series circuit is connected in series in the link. The coupling end of the positive unidirectional coupler (112) is connected to the input end of the second positive power detection circuit (123). The coupling end of the anti-unidirectional coupler (113) is connected to the input end of the second reverse power detection circuit (124). The output ends of the second positive power detection circuit (123) and the second reverse power detection circuit (124) are both connected to the comparison trigger module (200).

7. The protection circuit for a radio frequency front-end circuit according to claim 4, characterized in that, The coupler unit (110) includes a second bidirectional coupler (114) and a first time-division switching unit (115). The signal conversion unit (120) includes a bidirectional power detection circuit (125) and a second time-division switching unit (126). The main line of the second bidirectional coupler (114) is connected in series in the link. The first time-division input terminal of the first time-division switching unit (115) is connected to the positive coupling terminal of the second bidirectional coupler (114). The second time-division input terminal of the first time-division switching unit (115) is connected to the positive coupling terminal of the second bidirectional coupler (114). The first time-division switching unit (115) is connected to the reverse coupling terminal of the coupler (114), the output terminal of the first time-division switching unit (115) is connected to the input terminal of the bidirectional power detection circuit (125), the output terminal of the bidirectional power detection circuit (125) is connected to the input terminal of the second time-division switching unit (126), the first time-division output terminal and the second time-division output terminal of the second time-division switching unit (126) are both connected to the comparison trigger module (200), and the first time-division switching unit (115) and the second time-division switching unit (126) switch synchronously.

8. A protection circuit for a radio frequency front-end circuit according to any one of claims 4 to 7, characterized in that, The signal conversion unit (120) includes at least one power detection circuit, which includes a DC blocking circuit (130), a subtraction circuit (140), and a filter voltage regulator circuit (150). The input terminal of the DC blocking circuit (130) is connected to the coupler unit (110), the output terminal of the DC blocking circuit (130) is connected to the input terminal of the subtraction circuit (140), the output terminal of the subtraction circuit (140) is connected to the input terminal of the filter voltage regulator circuit (150), and the output terminal of the filter voltage regulator circuit (150) is connected to the comparison trigger module (200). The DC blocking circuit (130) is used to isolate the DC component of the input signal, and the subtraction circuit (140) is used to subtract the input DC bias from the input signal.

9. A protection circuit for a radio frequency front-end circuit according to claim 8, characterized in that, The power detection circuit also includes a current mirror circuit (160), the input terminal of which is connected to the output terminal of the subtraction circuit (140), and the output terminal of which is connected to the filter and voltage regulator circuit (150).

10. A protection circuit for a radio frequency front-end circuit according to claim 9, characterized in that, The DC blocking circuit (130) includes a DC blocking capacitor and a voltage divider circuit. One end of the DC blocking capacitor is connected to the coupler unit (110), one end of the voltage divider circuit is connected to the power supply terminal, the other end of the voltage divider circuit is grounded, and the other end of the DC blocking capacitor is connected to the midpoint of the voltage divider circuit and the input terminal of the subtraction circuit (140).

11. The protection circuit for a radio frequency front-end circuit according to claim 9, characterized in that, The subtraction circuit (140) includes a subtraction resistor, a subtraction capacitor, and a subtractor. The first input terminal of the subtractor is connected to the output terminal of the DC blocking circuit (130) and one end of the subtraction resistor. The second input terminal of the subtractor is connected to the other end of the subtraction resistor and one end of the subtraction capacitor. The other end of the subtraction capacitor is grounded. The output terminal of the subtractor is connected to the input terminal of the current mirror circuit (160).

12. A protection method for a radio frequency front-end circuit, characterized in that, The method, performed based on a protection circuit for a radio frequency front-end circuit as described in any one of claims 1 to 11, comprises: The forward power of the link is detected to form a first signal, and the reverse power in the link is detected to form a second signal; The first signal and the second signal are compared and processed to generate a trigger signal, wherein the trigger signal indicates that the output power of the link is greater than a first threshold or the standing wave ratio is greater than a second threshold. The output power of the power amplifier is adjusted according to the trigger signal.

13. A protection method for a radio frequency front-end circuit according to claim 12, characterized in that, The step of comparing the first signal and the second signal to generate a trigger signal includes: The trigger signal is generated when it is determined that the voltage of the first signal is greater than a preset multiple of the voltage of the second signal and the voltage of the first signal is greater than a first threshold voltage. Alternatively, the trigger signal is generated when it is determined that the voltage of the first signal is less than a preset multiple of the voltage of the second signal and the voltage of the second signal is greater than a second threshold voltage.

14. The protection method for a radio frequency front-end circuit according to claim 12, characterized in that, Adjusting the output power of the power amplifier according to the trigger signal includes: According to the trigger signal, the bias current of the power amplifier is turned off and maintained for a preset time. After the preset time, the bias current of the power amplifier is gradually increased to the preset bias current.

15. A radio frequency front-end module, characterized in that, It includes a radio frequency front-end circuit and a protection circuit for the radio frequency front-end circuit as described in any one of claims 1 to 11.

16. A radio frequency front-end module according to claim 15, characterized in that, The radio frequency front-end circuit includes a power amplifier (410), a switching module (420), and a filter module (430). The power amplifier (410), the bidirectional power detection module (100), the switching module (420), and the filter module (430) are connected in sequence. The power control module (300) is connected to the power amplifier (410).

17. A radio frequency device, characterized in that, It includes a radio frequency front-end circuit and a protection circuit for the radio frequency front-end circuit as described in any one of claims 1 to 11.

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