A radio frequency front-end module, electronic device, and method with impedance mismatch protection

Abstract

This invention discloses a radio frequency (RF) front-end module, electronic device, and method with impedance mismatch protection. The RF front-end module includes at least one transmission path, which comprises an input power detection circuit, a power amplifier circuit, a matching circuit, a load detection circuit, and a gain control circuit. The input power detection circuit detects the input RF signal power of the transmission path. The load detection circuit detects the forward and reverse transmission power of the output RF signal and calculates the difference. The gain control circuit compares the input power value, the difference between the forward and reverse transmission power, and the input power value with a first threshold and a second threshold, respectively, and outputs a control signal generated from the comparison result to the power amplifier circuit to adjust the operating state of the power amplifier circuit, thereby achieving impedance mismatch protection.

Description

Technical Field

[0001] This invention relates to a radio frequency (RF) front-end module with impedance mismatch protection, as well as to electronic devices including the RF front-end module, and to a control method for implementing impedance mismatch protection in the RF front-end module, belonging to the field of radio frequency integrated circuit technology. Background Technology

[0002] In mobile communication devices, the theoretical design of RF antennas dictates that the input and output impedances of the RF front-end module are both 50Ω. However, in practical applications, the antenna load can significantly deviate from 50Ω due to changes in surrounding environmental factors. For example, abnormal loads, temperature variations, and changes in handling can all lead to load impedance mismatch, causing RF signal reflection and increasing the Voltage Standing Wave Ratio (VSWR). Furthermore, power amplifier specifications such as gain, power consumption, and linearity are typically designed based on the theoretical assumption of a 50Ω impedance, resulting in a discrepancy between actual and theoretical performance. When the input power of the power amplifier is high, severe load impedance mismatch can cause the voltage or current to increase and approach its limits, potentially burning out components. Therefore, load impedance mismatch poses a fatal threat to the reliability of power amplifier operation.

[0003] In existing technology, one way to solve the above problem is to reduce the gain of the power amplifier or directly shut down the power amplifier when the load impedance mismatch is too large, thereby protecting the power amplifier from component burnout due to load impedance mismatch. However, this method has two drawbacks: first, when the input power of the power amplifier is low, even if the load impedance mismatch is too large, the power amplifier will not be burned out, and the power amplifier should continue to operate normally; second, it cannot guarantee the safety of the power amplifier when switching from the protection state to the normal operating state.

[0004] Chinese utility model patent ZL 201822139086.2 discloses a power amplifier circuit with mismatch protection. This power amplifier circuit includes an input matching unit, an output matching unit, and a power amplifier die connected between the input matching unit and the output matching unit. A Zener diode is electrically connected between the power amplifier die and GND, and the Zener diode provides mismatch protection when the power amplifier die experiences load mismatch. This technical solution, by introducing a Zener diode between the power amplifier and GND, enables the Zener diode to stabilize the drain voltage of the power amplifier within a safe range when load mismatch occurs, thus providing mismatch protection for the power amplifier circuit and improving the open-circuit robustness of the power amplifier. Summary of the Invention

[0005] The primary technical problem to be solved by this invention is to provide a radio frequency front-end module with impedance mismatch protection.

[0006] Another technical problem to be solved by the present invention is to provide an electronic device including the radio frequency front-end module.

[0007] Another technical problem to be solved by the present invention is to provide a control method for implementing impedance mismatch protection in a radio frequency front-end module.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] According to a first aspect of the present invention, a radio frequency front-end module with impedance mismatch protection is provided, comprising at least one transmit path, the transmit path including an input power detection circuit, a power amplifier circuit, a matching circuit, a load detection circuit, and a gain control circuit; wherein,

[0010] The input power detection circuit is used to detect the input radio frequency signal power of the transmission path. Its input terminal is connected to the radio frequency signal input terminal, its first output terminal is connected to the input terminal of the power amplifier circuit, and its second output terminal is connected to the first input terminal of the gain control circuit.

[0011] The power amplifier circuit is used to amplify the power of the input radio frequency signal and output it, and its output terminal is connected to the input terminal of the matching circuit.

[0012] The matching circuit is used to achieve impedance matching, and its output is connected to the input of the load detection circuit.

[0013] The load detection circuit is used to detect the forward transmission power and reverse transmission power of the output radio frequency signal, and calculate the difference between the forward transmission power and the reverse transmission power as the output signal. The first output terminal is connected to the radio frequency signal output terminal, and the second output terminal is connected to the second input terminal of the gain control circuit.

[0014] The output terminal of the gain control circuit is connected to the control terminal of the power amplifier circuit. It is used to compare the received input power value with a first threshold, compare the difference between the output forward transmission power and the reverse transmission power with a second threshold, and output the control signal generated by the comparison result to the power amplifier circuit to adjust the working state of the power amplifier circuit.

[0015] Preferably, the load detection circuit includes a first directional coupler, a second directional coupler, and a power differential unit; wherein...

[0016] The first directional coupler and the second directional coupler are connected in series in reverse in the radio frequency signal path; the output terminal of the first directional coupler is connected to the first input terminal of the power differential unit, the output terminal of the second directional coupler is connected to the second input terminal of the power differential unit, and the output terminal of the power differential unit is connected to the second input terminal of the gain control circuit.

[0017] Preferably, the first directional coupler is forward connected and used to detect the power of the radio frequency signal transmitted in the forward direction on the signal path;

[0018] The second directional coupler is connected in reverse and is used to detect the reflected signal power transmitted in reverse due to impedance mismatch in the signal path.

[0019] Preferably, when the load impedance is mismatched, the difference between the forward transmission power and the reverse transmission power detected by the first directional coupler and the second directional coupler changes in the opposite direction with the voltage standing wave ratio.

[0020] Preferably, the gain control circuit includes a first comparator, a second comparator, and a first AND gate; wherein...

[0021] The first input terminal of the first comparator is connected to the output terminal of the input power detection circuit, the second input terminal of the first comparator is connected to the first threshold terminal, and the output terminal of the first comparator is connected to the first input terminal of the first AND gate; the first input terminal of the second comparator is connected to the output terminal of the load detection circuit, the second input terminal of the second comparator is connected to the second threshold terminal, and the output terminal of the second comparator is connected to the second input terminal of the first AND gate; the output terminal of the first AND gate is connected to the control terminal of the attenuator unit in the power amplifier circuit.

[0022] Preferably, when the detected input power is greater than or equal to the first threshold, and the difference between the forward transmission power and the reverse transmission power of the output signal is less than or equal to the second threshold, the first AND gate outputs a high-level control signal to control the attenuator unit in the power amplifier circuit to start, so that the input radio frequency signal of the transmission path enters the power amplifier unit after at least one attenuation. At this time, the power amplifier circuit is in a protection working state.

[0023] Preferably, when the detected input power is less than a first threshold and / or the difference between the forward and reverse transmission power of the output signal is greater than a second threshold, the first AND gate outputs a low-level control signal to control the attenuator unit in the power amplifier circuit to turn off, and the input radio frequency signal of the transmission path directly enters the power amplifier unit. At this time, the power amplifier circuit is in normal working condition.

[0024] Preferably, the output terminal of the gain control circuit is connected to the adjustable bias circuit unit in the power amplifier circuit; the control signal output by the gain control circuit controls the adjustable bias circuit in the power amplifier circuit, and the gain of the power amplifier circuit is adjusted by adjusting the magnitude of the bias voltage or current output by the bias circuit, thereby achieving impedance mismatch protection.

[0025] Preferably, the control signal output by the gain control circuit is used to control the bias resistor or power supply in the adjustable bias circuit unit to change the magnitude of the output bias current or voltage.

[0026] When the control signal output by the gain control circuit is high, the bias current or voltage output by the adjustable bias circuit is reduced, thereby reducing the gain of the power amplifier circuit. At this time, the power amplifier circuit is in a protection state.

[0027] When the control signal output by the gain control circuit is low, the bias current or voltage output by the adjustable bias circuit is adjusted to maintain or restore the normal value. At this time, the power amplifier circuit is in normal working condition.

[0028] According to a second aspect of the present invention, an electronic device is provided, including the radio frequency front-end module with impedance mismatch protection described above.

[0029] According to a third aspect of the present invention, a control method for implementing impedance mismatch protection in a radio frequency front-end module is provided, comprising the following steps:

[0030] (1) Set the first threshold and the second threshold;

[0031] (2) Detect the input power of the radio frequency signal in the transmission path;

[0032] (3) Detect the forward transmission power and reverse transmission power of the output RF signal, and calculate the difference between the forward transmission power and the reverse transmission power;

[0033] (4) Compare the detected input power with the first threshold;

[0034] (5) Compare the difference between the detected forward transmission power and reverse transmission power at the output end with the second threshold;

[0035] (6) When the detected input power is greater than or equal to the first threshold, and the difference between the forward transmission power and the reverse transmission power at the output end is less than or equal to the second threshold, proceed to step (7); otherwise, proceed to step (8).

[0036] (7) Start the attenuator in the power amplifier circuit, and the input RF signal enters the power amplifier unit through the attenuator; then proceed to step (2);

[0037] (8) Turn off the attenuator in the power amplifier circuit and let the input RF signal directly enter the power amplifier unit; then proceed to step (2).

[0038] Preferably, step (7) adopts the following sub-steps:

[0039] Reduce the bias current or voltage in the power amplifier circuit to reduce the gain of the power amplifier circuit; then proceed to step (2).

[0040] Preferably, step (8) adopts the following sub-steps:

[0041] Maintain or restore the bias current or voltage in the power amplifier circuit to maintain or restore the gain of the power amplifier circuit to normal operation; then proceed to step (2).

[0042] Compared with existing technologies, the RF front-end module with impedance mismatch protection provided in this invention achieves effective protection of the power amplifier circuit's reliability under harsh conditions of high input power and severe load impedance mismatch by employing a technical solution that dynamically adjusts the power amplifier circuit gain based on real-time detection of the input power of the RF signal and the difference between the forward and reverse output power (representing the voltage standing wave ratio). Furthermore, the power amplifier circuit can smoothly return to normal operation when the harsh operating conditions are alleviated. Therefore, the RF front-end module with impedance mismatch protection provided in this invention has the advantages of ingenious and reasonable structural design, low design cost, high operational reliability, and excellent circuit performance. Attached Figure Description

[0043] Figure 1 A structural block diagram of an RF front-end module with impedance mismatch protection provided in an embodiment of the present invention;

[0044] Figure 2 A circuit schematic diagram of an RF front-end module with impedance mismatch protection is shown in one embodiment of the present invention.

[0045] Figure 3 This is a graph showing the difference between forward and reverse transmission power under different VSWRs in an embodiment of the present invention.

[0046] Figure 4 This is a circuit schematic diagram of an RF front-end module with impedance mismatch protection in another embodiment of the present invention.

[0047] Figure 5 This is a circuit structure diagram of an adjustable bias circuit unit in another embodiment of the present invention;

[0048] Figure 6This is a flowchart illustrating the control method for impedance mismatch protection implemented by the radio frequency front-end module in this embodiment of the invention.

[0049] Figure 7 This is a schematic diagram of an electronic device employing an RF front-end module with impedance mismatch protection provided in an embodiment of the present invention. Detailed Implementation

[0050] The technical content of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] like Figure 1 As shown, an embodiment of the present invention provides an RF front-end module with impedance mismatch protection, comprising at least one transmission path. This transmission path includes an input power detection circuit 101, a power amplifier circuit 102, a matching circuit 103, a load detection circuit 104, and a gain control circuit 105. The RF signal input terminal TX_in is connected to the input terminal of the input power detection circuit 101. The first output terminal of the input power detection circuit 101 is connected to the input terminal of the power amplifier circuit 102. The second output terminal of the input power detection circuit 101 is connected to the first input terminal of the gain control circuit 105. The output terminal of the power amplifier circuit 102 is connected to the input terminal of the matching circuit 103. The output terminal of the matching circuit 103 is connected to the input terminal of the load detection circuit 104. The first output terminal of the load detection circuit 104 is connected to the RF signal output terminal TX_out. The second output terminal of the load detection circuit 104 is connected to the second input terminal of the gain control circuit 105. The output terminal of the gain control circuit 105 is connected to the control terminal of the power amplifier circuit 102. The RF signal output terminal TX_out is connected to the antenna ANT.

[0052] The input power detection circuit 101 is used to detect the input radio frequency signal power of the transmission path and output the detection result to the gain control circuit 105. The input power detection circuit can be implemented using a directional coupler.

[0053] The power amplifier circuit 102 is used to amplify the power of the input radio frequency signal before outputting it. A power amplifier circuit typically includes a power amplification unit and a bias circuit unit, and may also include attenuator units, etc., depending on specific needs.

[0054] The matching circuit 103 is used to achieve impedance matching and is generally composed of passive components such as capacitors and inductors.

[0055] The load detection circuit 104 is used to detect the forward transmission power and reverse transmission power of the output RF signal, and outputs the difference between the forward transmission power and the reverse transmission power to the gain control circuit 105.

[0056] The gain control circuit 105 is used to compare the difference between the received input power value, the output forward transmission power and the reverse transmission power with the set first threshold and the second threshold respectively, and output the control signal generated by the comparison result to the power amplifier circuit 102 to adjust the working state of the power amplifier circuit.

[0057] like Figure 2 As shown, in one embodiment of the present invention, the load detection circuit 104 includes a first directional coupler DC1, a second directional coupler DC2, and a power differential unit. The first directional coupler DC1 and the second directional coupler DC2 are connected in series in reverse in the radio frequency signal path; the coupling output terminal of the first directional coupler DC1 is connected to the first input terminal of the power differential unit, the coupling output terminal of the second directional coupler DC2 is connected to the second input terminal of the power differential unit, and the output terminal of the power differential unit is connected to the second input terminal of the gain control circuit 105.

[0058] The first directional coupler, DC1, is connected in the forward direction and is used to detect the power of the RF signal transmitted in the forward direction on the signal path. The second directional coupler, DC2, is connected in the reverse direction and is used to detect the reflected signal power transmitted in the reverse direction on the signal path due to impedance mismatch. When the load impedance is 50Ω (or other impedance values), the difference between the forward and reverse transmission power detected by the first directional coupler DC1 and the second directional coupler DC2 is the same as the isolation of the directional coupler itself. When there is a load impedance mismatch, the difference between the forward and reverse transmission power detected by the first directional coupler DC1 and the second directional coupler DC2 becomes smaller.

[0059] like Figure 3 As shown, the voltage standing wave ratio (VSWR) varies depending on the degree of load impedance mismatch, and the difference between the forward and reverse transmission power detected by the first directional coupler DC1 and the second directional coupler DC2 is also different. Figure 3 In the graph, the horizontal axis represents phase, and the vertical axis represents the difference between forward and reverse transmission power. When the voltage standing wave ratio (VSWR) is 3:1, the difference between forward and reverse transmission power is 6.2 dB under full-phase conditions; when the VSWR is 6:1, the difference is 3 dB under full-phase conditions; and when the VSWR is 12:1, the difference is 1.5 dB under full-phase conditions.

[0060] In other words, the difference between the forward and reverse transmission power detected by the first directional coupler DC1 and the second directional coupler DC2 decreases as the voltage standing wave ratio (VSWR) increases (i.e., changes in the opposite direction), and the larger the VSWR, the more severe the load impedance mismatch.

[0061] The circuit structure of the power difference unit can be made of electronic components or it can be made of electronic components plus algorithm processing.

[0062] like Figure 2 As shown, in one embodiment of the present invention, the gain control circuit 105 includes a first comparator COM1, a second comparator COM2, and a first AND gate. The first input terminal of the first comparator COM1 is connected to the output terminal of the input power detection circuit, the second input terminal of the first comparator COM1 is connected to a first threshold terminal set by the system, and the output terminal of the first comparator COM1 is connected to the first input terminal of the first AND gate. The first input terminal of the second comparator COM2 is connected to the output terminal of the load detection circuit, the second input terminal of the second comparator COM2 is connected to a second threshold terminal set by the system, and the output terminal of the second comparator COM2 is connected to the second input terminal of the first AND gate. The output terminal of the first AND gate is connected to the control terminal of the attenuator unit in the power amplifier circuit.

[0063] The first comparator COM1 compares the input power of the RF signal detected by the input power detection circuit with a first threshold set by the system. This first threshold is a predetermined input power value. When the detected input power value is greater than or equal to this first threshold, the first comparator COM1 outputs a high level; otherwise, it outputs a low level. The second comparator COM2 compares the difference between the forward and reverse transmission power of the RF signal detected by the load detection circuit with a second threshold set by the system. This second threshold is the difference between the forward and reverse transmission power at a predetermined voltage standing wave ratio (VSWR) under load impedance mismatch. When the difference between the forward and reverse transmission power of the RF signal detected by the load detection circuit is less than or equal to this second threshold, the second comparator COM2 outputs a high level; otherwise, it outputs a low level. The output signals of the first comparator COM1 and the second comparator COM2 are ANDed by a first AND gate to output a control signal, which controls the attenuator unit in the power amplifier circuit.

[0064] When the detected input power is greater than or equal to the first threshold, and the difference between the forward and reverse transmission power of the output signal is less than or equal to the second threshold, the first AND gate outputs a high-level control signal to control the attenuator unit in the power amplifier circuit to start, so that the input RF signal of the transmission path enters the power amplifier unit after at least one attenuation.

[0065] When the detected input power is less than the first threshold, and / or the difference between the forward and reverse transmission power of the output signal is greater than the second threshold, the first AND gate outputs a low-level control signal, which controls the attenuator unit in the power amplifier circuit to turn off, and the input RF signal of the transmission path directly enters the power amplifier unit.

[0066] In other words, when the input power is less than the first threshold, the attenuator unit in the power amplifier circuit will not activate regardless of the voltage standing wave ratio (VSWR), which represents the degree of load impedance mismatch. At this time, the power amplifier circuit remains in normal operation. Conversely, when the difference between the forward and reverse transmission power of the output signal is greater than the second threshold, the attenuator unit in the power amplifier circuit will not activate regardless of the input power. At this time, the power amplifier circuit remains in normal operation. Only when the detected input power is greater than or equal to the first threshold, and the difference between the forward and reverse transmission power of the output signal is less than or equal to the second threshold, will the attenuator unit in the power amplifier circuit activate. In this case, the power amplifier circuit is in a protection state, thus ensuring that the power amplifier circuit will not be burned out.

[0067] When the power amplifier circuit is in protection mode, if the input power decreases to less than the first threshold, the first comparator COM1 outputs a low level, and the first AND gate outputs a low level control signal. The attenuator unit in the power amplifier circuit is turned off, and the power amplifier circuit returns to normal operation, maintaining normal gain. If the difference between the forward and reverse transmission power of the output signal increases to greater than the second threshold, the second comparator COM2 outputs a low level, and the first AND gate outputs a low level control signal. The attenuator unit in the power amplifier circuit is turned off, and the power amplifier circuit returns to normal operation, maintaining normal gain.

[0068] As can be seen from the above analysis of the working principle, the technical solution provided by the embodiments of the present invention can effectively protect the power amplifier circuit under adverse conditions such as large input power and severe load impedance mismatch, and can also enable the power amplifier circuit to smoothly return to normal working state when the adverse working conditions are alleviated.

[0069] The attenuator unit in the power amplifier circuit is connected in series at the input terminal of the power amplifier unit in the signal path, and it can be implemented using an array circuit composed of switches, resistors and capacitors.

[0070] like Figure 4As shown, in another embodiment of the present invention, the RF front-end module with impedance mismatch protection includes at least one transmit path. This transmit path includes an input power detection circuit, a power amplifier circuit 102, a matching circuit, a load detection circuit 104, and a gain control circuit 105. The structures of the load detection circuit 104, the gain control circuit 105, the input power detection circuit, and the matching circuit are the same as in the above embodiment, except that the output terminal of the gain control circuit 105 is connected to the adjustable bias circuit unit in the power amplifier circuit 102.

[0071] In this embodiment, the control signal output by the gain control circuit 105 controls the adjustable bias circuit in the power amplifier circuit 102. By adjusting the magnitude of the bias voltage or current output by the bias circuit, the gain of the power amplifier circuit is adjusted. This effectively protects the power amplifier circuit under adverse conditions such as high input power and severe load impedance mismatch, and ensures that the power amplifier circuit smoothly returns to normal operation when the adverse operating conditions are alleviated. Other specific working processes of the technical solution provided in this embodiment are the same as those in the above embodiments, and therefore will not be repeated.

[0072] The circuit structure of the adjustable bias circuit unit in the power amplifier circuit 102 is as follows: Figure 5 As shown, the control signal output by the gain control circuit 105 can be adjusted by changing the magnitude of the output bias current or voltage by adjusting the bias resistor R2 or the power supply Vcc, thereby adjusting the gain of the power amplifier circuit.

[0073] When the control signal output by the gain control circuit 105 is high, the bias current or voltage output by the bias circuit is reduced, thereby reducing the gain of the power amplifier circuit. At this time, the power amplifier circuit is in a protection state. When the control signal output by the gain control circuit 105 is low, the bias current or voltage output by the bias circuit is maintained or restored to its normal value. At this time, the power amplifier circuit is in a normal working state.

[0074] The impedance mismatch protection control method of the RF front-end module provided in this embodiment of the invention has the following working process: Figure 6 As shown, the specific steps include the following:

[0075] S1: Set the predetermined input power value at the input terminal to a first threshold value, and set the predetermined difference between the forward transmission power and the reverse transmission power at the output terminal to a second threshold value.

[0076] S2: Detects the input power of the radio frequency signal in the transmission path.

[0077] S3: Detect the forward and reverse transmission power of the output RF signal and calculate the difference between the forward and reverse transmission power.

[0078] S4: Compare the detected input power with the first threshold.

[0079] S5: Compare the difference between the detected forward and reverse transmission power at the output terminal with the second threshold.

[0080] S6: When the detected input power is greater than or equal to the first threshold, and the difference between the forward transmission power and the reverse transmission power at the output terminal is less than or equal to the second threshold, proceed to step S7; otherwise, proceed to step S8.

[0081] S7: Start the attenuator in the power amplifier circuit, and the input RF signal enters the power amplifier unit through the attenuator; then proceed to step S2.

[0082] S8: Turn off the attenuator unit in the power amplifier circuit, and the input RF signal directly enters the power amplifier unit; then proceed to step S2.

[0083] In the above workflow, steps S2 and S3 are performed simultaneously, as are steps S4 and S5. Additionally, steps S7 and S8 can also employ the following technical solutions:

[0084] S71: Reduce the bias current or voltage in the power amplifier circuit to reduce the gain of the power amplifier circuit; then proceed to step S2.

[0085] S81: Maintain or restore the bias current or voltage in the power amplifier circuit to maintain or restore the gain of the power amplifier circuit to normal operation; then proceed to step S2.

[0086] Based on the aforementioned RF front-end module with impedance mismatch protection, embodiments of the present invention also provide an electronic device, including the aforementioned RF front-end module with impedance mismatch protection, which can serve as an important component of a communication assembly. The electronic device referred to herein is a computer device that can be used in a mobile environment and supports multiple communication standards such as GSM, EDGE, CDMA, TD-SCDMA, WCDMA, TDD-LTE, FDD-LTE, and NR, including mobile phones, laptops, tablets, and in-vehicle computers. Furthermore, the technical solution provided by the present invention is also applicable to other applications of RF integrated circuits, such as communication base stations and intelligent connected vehicles.

[0087] like Figure 7As shown, this electronic device includes at least a processor, a memory, and a communication component. It may further include sensor components, a power supply component, a multimedia component, and input / output interfaces, depending on actual needs. The memory, communication component, sensor component, power supply component, multimedia component, and input / output interface are all connected to the processor. The memory can be a static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, etc. The processor can be a central processing unit (CPU), graphics processing unit (GPU), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), digital signal processing (DSP) chip, etc. Other communication components, sensor components, power supply components, multimedia components, etc., can be implemented using general-purpose components and will not be specifically described here.

[0088] In summary, compared with existing technologies, the RF front-end module with impedance mismatch protection provided by this invention, through a technical solution of dynamically adjusting the gain of the power amplifier circuit by real-time detection of the input power of the RF signal and the difference between the forward and reverse output power representing the voltage standing wave ratio (VSWR), effectively protects the reliability of the power amplifier circuit under harsh conditions of high input power and severe load impedance mismatch. Furthermore, the power amplifier circuit can smoothly return to normal operation when the harsh operating conditions are alleviated. Therefore, the RF front-end module with impedance mismatch protection provided by this invention has the advantages of ingenious and reasonable structural design, low design cost, high operational reliability, and excellent circuit performance.

[0089] It should be noted that the above embodiments are merely examples, and the technical solutions of each embodiment can be combined, all of which are within the protection scope of this invention.

[0090] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0091] The foregoing has provided a detailed description of the RF front-end module, electronic device, and method with impedance mismatch protection provided by this invention. Any obvious modifications made by those skilled in the art without departing from the essence of this invention will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

Claims

1. A radio frequency front-end module with impedance mismatch protection, characterized in that... It includes at least one transmission path, which comprises an input power detection circuit, a power amplifier circuit, a matching circuit, a load detection circuit, and a gain control circuit; wherein, The input power detection circuit is used to detect the input radio frequency signal power of the transmission path. Its input terminal is connected to the radio frequency signal input terminal, its first output terminal is connected to the input terminal of the power amplifier circuit, and its second output terminal is connected to the first input terminal of the gain control circuit. The power amplifier circuit is used to amplify the power of the input radio frequency signal and output it, and its output terminal is connected to the input terminal of the matching circuit. The matching circuit is used to achieve impedance matching, and its output is connected to the input of the load detection circuit. The load detection circuit is used to detect the forward and reverse transmission power of the output RF signal and output the difference between the forward and reverse transmission power. The first output terminal of the load detection circuit is connected to the RF signal output terminal, and the second output terminal of the load detection circuit is connected to the second input terminal of the gain control circuit. The load detection circuit includes a first directional coupler, a second directional coupler, and a power difference unit. The first directional coupler is connected in the forward direction to detect the forward transmission power of the RF signal in the signal path. The second directional coupler is connected in the reverse direction to detect the reflected signal power in the reverse transmission due to impedance mismatch in the signal path. The output of the gain control circuit is connected to the control terminal of the power amplifier circuit. It is used to compare the received input RF signal power with a first threshold, compare the difference between the received forward and reverse transmission power with a second threshold, and output a control signal generated from the comparison results to the power amplifier circuit to adjust the operating state of the power amplifier circuit. When the detected input RF signal power is greater than or equal to a first threshold, and the difference between the forward transmission power and the reverse transmission power is less than or equal to a second threshold, the attenuator unit in the power amplifier circuit is activated, so that the input RF signal of the transmission path is attenuated at least once before power amplification. At this time, the power amplifier circuit is in a protection state. Alternatively, the output terminal of the gain control circuit is connected to the adjustable bias circuit in the power amplifier circuit. The control signal output by the gain control circuit controls the adjustable bias circuit in the power amplifier circuit. By adjusting the magnitude of the bias voltage or bias current output by the adjustable bias circuit, the gain of the power amplifier circuit is adjusted to achieve impedance mismatch protection.

2. The RF front-end module with impedance mismatch protection as described in claim 1, characterized in that: In the load detection circuit, the first directional coupler and the second directional coupler are connected in reverse series in the radio frequency signal path; the output terminal of the first directional coupler is connected to the first input terminal of the power differential unit, the output terminal of the second directional coupler is connected to the second input terminal of the power differential unit, and the output terminal of the power differential unit is connected to the second input terminal of the gain control circuit.

3. The RF front-end module with impedance mismatch protection as described in claim 2, characterized in that: When the load impedance is mismatched, the difference between the forward transmission power and the reverse transmission power detected by the first directional coupler and the second directional coupler changes in the opposite direction with the voltage standing wave ratio.

4. The RF front-end module with impedance mismatch protection as described in claim 1, characterized in that: The gain control circuit includes a first comparator, a second comparator, and a first AND gate; wherein, the first input terminal of the first comparator is connected to the output terminal of the input power detection circuit, a first threshold is input to the second input terminal of the first comparator, and the output terminal of the first comparator is connected to the first input terminal of the first AND gate; the first input terminal of the second comparator is connected to the output terminal of the load detection circuit, a second threshold is input to the second input terminal of the second comparator, and the output terminal of the second comparator is connected to the second input terminal of the first AND gate; the output terminal of the first AND gate is connected to the control terminal of the attenuator unit in the power amplifier circuit, or the output terminal of the first AND gate is connected to the adjustable bias circuit in the power amplifier circuit.

5. The RF front-end module with impedance mismatch protection as described in claim 4, characterized in that: When the detected input RF signal power is less than the first threshold and / or the difference between the forward transmission power and the reverse transmission power is greater than the second threshold, the first AND gate outputs a low-level control signal to control the attenuator unit in the power amplifier circuit to turn off, and the input RF signal of the transmission path is directly amplified. At this time, the power amplifier circuit is in normal working condition.

6. The RF front-end module with impedance mismatch protection as described in claim 4, characterized in that: The control signal output by the gain control circuit changes the magnitude of the output bias current or bias voltage by controlling the bias resistor or power supply in the adjustable bias circuit. When the control signal output by the gain control circuit is high, the bias current or bias voltage output by the adjustable bias circuit is reduced, thereby reducing the gain of the power amplifier circuit. At this time, the power amplifier circuit is in a protection state. When the control signal output by the gain control circuit is low, the bias current or bias voltage output by the adjustable bias circuit is adjusted to the normal value. At this time, the power amplifier circuit is in normal working condition.

7. An electronic device, characterized in that... Includes the RF front-end module with impedance mismatch protection as described in any one of claims 1 to 6.

8. A control method for implementing impedance mismatch protection in a radio frequency front-end module, characterized in that... Includes the following steps: (1) Set a first threshold and a second threshold; (2) Detect the input radio frequency signal power of the transmission path; (3) Detect the forward transmission power and reverse transmission power of the output RF signal, and calculate the difference between the forward transmission power and the reverse transmission power; (4) Compare the detected input radio frequency signal power with the first threshold; (5) Compare the difference between the detected forward transmission power and reverse transmission power at the output end with the second threshold; (6) When the detected input RF signal power is greater than or equal to the first threshold, and the difference between the output forward transmission power and the reverse transmission power is less than or equal to the second threshold, proceed to step (7); otherwise, proceed to step (8). (7) Start the attenuator unit in the power amplifier circuit. The input radio frequency signal is amplified after passing through the attenuator unit; then proceed to step (2). (8) Turn off the attenuator unit in the power amplifier circuit and directly amplify the power of the input RF signal; then proceed to step (2). The radio frequency front-end module is the radio frequency front-end module with impedance mismatch protection as described in any one of claims 1 to 6.

9. The control method for impedance mismatch protection of the RF front-end module as described in claim 8, characterized in that: Step (7) is replaced by the following sub-step: reduce the bias current or bias voltage in the power amplifier circuit to reduce the gain of the power amplifier circuit; then proceed to step (2); Step (8) is replaced by the following sub-step: maintain or restore the bias current or bias voltage in the power amplifier circuit to maintain or restore the gain of the power amplifier circuit to normal operation; then proceed to step (2).

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