Protecting circuits and electronic equipment

Abstract

The present application discloses a protection circuit, which belongs to the field of integrated circuits. The protection circuit includes: an amplifier, a signal separation element, a delay element, a signal conversion element and an attenuation unit, the input end of the signal separation element is connected to the RF signal output port, the first output end of the signal separation element is connected to the input end of the delay element, and the second output end of the signal separation element is connected to the input end of the signal conversion element; the output end of the delay element is connected to the input end of the amplifier; the attenuation unit is connected between the output end of the delay element and the output end of the signal conversion element; wherein, when the output voltage of the output end of the signal conversion element reaches a preset threshold, the attenuation unit is turned on, and the RF signal delayed output from the output end of the delay element is attenuated. The present application can protect the amplifier from damage by high-power RF signals.

Description

Technical Field

[0001] The present application belongs to the field of integrated circuits, and specifically relates to a protection circuit and an electronic device. Background Art

[0002] In order to improve the receiving performance and sensitivity of the RF signal receiving circuit, a lower power amplifier is often used in the RF signal receiving circuit. However, the tolerance of the low-power amplifier is relatively weak. When the input power of the received RF signal is relatively strong, the high input power is easy to cause irreversible and permanent damage to the amplifier during use. Furthermore, it may cause the receiving circuit to malfunction and the performance of the receiving circuit to deteriorate. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a protection circuit and an electronic device that can solve the problem that high-power radio frequency signals can easily cause damage to the amplifier.

[0004] In order to solve the above technical problems, this application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a protection circuit, the circuit comprising: an amplifier, a signal separation element, a delay element, a signal conversion element and an attenuation unit;

[0006] The input end of the signal separation element is connected to the RF signal output port, the first output end of the signal separation element is connected to the input end of the delay element, and the second output end of the signal separation element is connected to the input end of the signal conversion element; the output end of the delay element is connected to the input end of the amplifier; the attenuation unit is connected between the output end of the delay element and the output end of the signal conversion element;

[0007] When the output voltage of the output end of the signal conversion element reaches a preset threshold, the attenuation unit is turned on and performs attenuation processing on the radio frequency signal delayed output from the output end of the delay element.

[0008] In a second aspect, an embodiment of the present application provides an electronic device, comprising the protection circuit as described in the first aspect above.

[0009] In an embodiment of the present application, the protection circuit includes an amplifier, a signal separation element, a delay element, a signal conversion element and an attenuation unit. When the output voltage of the output end of the signal conversion element reaches a preset threshold, the attenuation unit is turned on and attenuates the radio frequency signal delayed output by the output end of the delay element, thereby triggering the protection circuit and responding in time before the high-power radio frequency signal reaches the amplifier, attenuating the high-power signal, and being able to protect the amplifier from damage by the high-power radio frequency signal in real time and effectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a block diagram of the protection circuit structure of an embodiment of the present application.

[0011] Figure 2 It is a circuit structure diagram of the protection circuit of the first embodiment of the present application.

[0012] Figure 3 Schematic diagram of the voltage-power conversion curve of the detector diode according to the embodiment of the present application.

[0013] Figure 4 It is a schematic diagram of a method for determining a preset delay duration in an embodiment of the present application.

[0014] Figure 5 It is a circuit structure diagram of the protection circuit of the second embodiment of the present application.

[0015] Figure 6 It is a schematic diagram of the operation flow of the protection circuit of an embodiment of the present application.

[0016] Figure 7 It is a schematic diagram of the hardware structure of the electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0019] The protection circuit provided in the embodiment of the present application is described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0020] An embodiment of the present application provides a protection circuit, including an amplifier, a signal separation element, a delay element, a signal conversion element and an attenuation unit, wherein the input end of the signal separation element is connected to the RF signal output port, the first output end of the signal separation element is connected to the input end of the delay element, and the second output end of the signal separation element is connected to the input end of the signal conversion element; the output end of the delay element is connected to the input end of the amplifier; the attenuation unit is connected between the output end of the delay element and the output end of the signal conversion element; wherein, when the output voltage of the output end of the signal conversion element reaches a preset threshold, the attenuation unit is turned on and the RF signal delayed output from the output end of the delay element is attenuated.

[0021] The amplifier here may be a low-power amplifier, such as a low-noise amplifier (Low Noise Amplifier, LNA), which has a relatively small withstand power.

[0022] Reference now Figure 1 , Figure 1 This is a block diagram of the protection circuit structure of an embodiment of the present application.

[0023] like Figure 1 As shown, the protection circuit 100 includes an amplifier 50 , a signal separation element 10 , a delay element 20 , a signal conversion element 30 and an attenuation unit 40 .

[0024] The input end of the signal separation element 10 is connected to the RF signal output port (not shown in the figure), the first output end is connected to the input end of the delay element 20, and the second output end is connected to the input end of the signal conversion element 30, so as to separate the received RF signal into two paths, namely the first RF signal and the second RF signal, which are respectively output to the delay element 20 and the signal conversion element 30. The two separated RF signals have the same power, which is the same as the power of the RF signal output from the RF signal output port.

[0025] The second RF signal output to the signal conversion element 30 can be a small part of the RF signal, which is used for subsequent detection of the RF signal power. Most of the RF signal, that is, the first RF signal, will be input to the delay element 20 and output by the delay element 20 after a preset delay time.

[0026] The delay element 20 may be a delay line, and the impedance of the delay line transmission is generally consistent with the impedance of the RF signal transmission line. For example, if a conventional RF signal is transmitted on a 50Ω impedance line, the delay element 20 may be a 50Ω delay line. The output end of the delay element 20 is connected to the input end of the amplifier 50, so that the delay element 20 delays the received first RF signal and then outputs it to the amplifier 50.

[0027] The signal conversion element 30 is used to convert the second RF signal into a voltage signal according to the power of the second RF signal, use the converted voltage signal to represent the power of the RF signal output from the RF signal output port, and input the converted voltage signal into the attenuation unit 40.

[0028] When the signal voltage outputted by the signal conversion element 30 after conversion reaches a preset threshold value, that is, when the power of the RF signal outputted from the RF signal output port reaches a predetermined power value, it indicates that the RF signal has exceeded the power tolerance of the amplifier, and the attenuation unit 40 is turned on, and it is necessary to perform attenuation processing, such as power attenuation, on the first RF signal outputted after the delay element 20. Then, the attenuated first RF signal is inputted into the amplifier 50, thereby preventing a high-power RF signal exceeding the power tolerance of the amplifier from being directly inputted into the amplifier and causing damage to the amplifier.

[0029] Regarding the preset delay time of the delay element 20, it is necessary to ensure that before the delay element 20 delays the output of the first RF signal, the attenuation unit 40 has enabled the attenuation limiting function so as to be able to timely attenuate the power of the first RF signal delayed output by the delay element 20.

[0030] If the signal voltage outputted by the signal conversion element 30 after conversion does not reach the preset threshold value, that is, the power of the RF signal outputted from the RF signal output port does not reach the predetermined power value, it means that the RF signal does not exceed the tolerable power of the amplifier 50 at this time, and the attenuation unit 40 will not start the attenuation limiting function, and accordingly will not attenuate the power of the first RF signal outputted after delay by the delay element 20. At this time, the first RF signal outputted after delay is directly inputted into the amplifier 50, and will not damage the amplifier.

[0031] The purpose of the delay element delay is: when the received RF signal may be a high-power RF signal that exceeds the amplifier's tolerance power, in order to avoid the high-power RF signal from damaging the amplifier, the delay element is set to delay the output of the RF signal, so as to first determine whether the received RF signal is a high-power RF signal within the preset delay time, and whether the attenuation unit needs to turn on the attenuation limiting function for the received RF signal. If the received RF signal is a high-power RF signal, it is necessary to turn on the attenuation limiting function of the attenuation unit before the delay time, and the attenuation unit shall promptly attenuate and limit the first RF signal output after the preset delay time, thereby avoiding the high-power first RF signal from being directly input into the amplifier without being attenuated or not being completely attenuated.

[0032] The preset duration is determined based on the time required for the first RF signal to reach the input end of the delay element 20 and the time required for the voltage value converted corresponding to the second RF signal to enable the attenuation unit 40 to start the attenuation limiting function.

[0033] The specific method for determining the preset delay time will be described in detail below in conjunction with specific embodiments.

[0034] Optionally, in one embodiment, the attenuation unit includes a first switch and a limiting element.

[0035] A first end of the first switch is connected to the output end of the signal conversion element, a second end of the first switch is connected to the first end of the amplitude limiting element, and a third end of the first switch is grounded;

[0036] The second end of the limiting element is connected to the output end of the delay element.

[0037] When the output voltage reaches a first preset voltage, the first switch is turned on and the limiting element is triggered to be enabled.

[0038] The structure of the attenuation unit can be referred to Figure 2 To explain, Figure 2 This is a circuit structure diagram of the protection circuit of the first embodiment of the present application.

[0039] exist Figure 2 In the embodiment, the signal separation element includes a microstrip coupler, the signal conversion unit includes a detection diode D1, and the delay element is a 50Ω delay line. The first switch includes a switch Q1, resistors R2 and R3, and the switch Q1 can be an NPN transistor. The limiting element is a limiting tube, including an integrated forward diode and a reverse diode.

[0040] Optionally, when the signal conversion element is a detection diode, the circuit further includes: an attenuation element connected between the second output end of the signal separation element and the input end of the detection diode.

[0041] The attenuation element is used to attenuate the power of the second radio frequency signal to a linear interval corresponding to the power-voltage conversion curve of the detection diode.

[0042] exist Figure 2 In the embodiment, the attenuation element is an attenuator ATT connected between the output end of the microstrip coupler and the input end of the detection diode D1.

[0043] Since the detection curve of the detection diode is not completely linear, there will be certain unequal proportional characteristics when converting power and voltage. This characteristic will cause power deviation corresponding to the preset threshold.

[0044] like Figure 3 As shown, Figure 3The power-voltage conversion curve of the detector diode is shown in the figure below. The range from -65dBm to 0dBm is a nonlinear range with non-uniform changes, and the range from 0dBm to 15dBm is a linear range. When the input power is in the nonlinear range, the ratio of power to voltage conversion is different. When the input power is in the linear range, the ratio of power to voltage conversion is basically the same.

[0045] The function of the attenuation element is to design a preset threshold value corresponding to the trigger power size of the attenuation unit to start the attenuation limiting function, which is within the linear range of the detection diode, thereby ensuring that the preset threshold value can accurately trigger the attenuation unit to timely attenuate the RF signal that meets the power attenuation conditions.

[0046] For example, the linear range of the detection diode is -10dBm to -40dBm, and the power of the second RF signal is 10dBm to -20dBm, which is 20dBm different from the linear range of the detection diode. The attenuation element first attenuates the received second RF signal by 20dBm, thereby adjusting the power of the second RF signal to fall within the linear range of the detection diode.

[0047] As described above, when the output voltage of the output terminal of the signal conversion element reaches the first preset voltage, the first switch is turned on, and the first power corresponding to the first preset voltage is less than the withstand power of the amplifier.

[0048] like Figure 2 As shown, an operational amplifier and resistors Rf and Rg are also connected between the detection diode D1 and the switch Q1. The resistors Rf and Rg of the operational amplifier and the resistors R2 and R3 of the first switch are determined based on the on and off states of the switch Q1 and the first preset voltage corresponding to the on state of the switch Q1. After the first preset voltage value is fixed, the ratio of each resistance value is also fixed accordingly.

[0049] Optionally, the difference between the tolerable power of the amplifier and the first power is 5-20dBm.

[0050] When the voltage value of the voltage signal converted from the power of the second RF signal reaches the first preset voltage, the switch Q1 is turned on. After the switch Q1 is turned on, the attenuation and amplitude limiting function of the amplitude limiting tube connected to the switch Q1 is immediately triggered and enabled, that is, the amplitude limiting tube can limit and attenuate the power of the first RF signal that is subsequently received and output with a delay.

[0051] In the above embodiment, the first preset time length of the 50Ω delay line delay is determined according to the first time length required for the first RF signal to reach the input end of the 50Ω delay line and the second time length required for the voltage signal corresponding to the second RF signal to turn on the switch Q1. When the delay time reaches the first preset time length, the output end of the delay element outputs the RF signal.

[0052] exist Figure 2 In an embodiment, the first time may also be the time required for the RF signal RF_IN to reach the input end of the 50Ω delay line after passing through the filter Filter and the microstrip coupler from the RF signal output port, and the second time may also be the time required for the RF signal RF_IN to pass through the filter Filter, the microstrip coupler, the attenuator ATT, the detection diode D1, the amplifier, the switch Q1 from the RF signal output port and make the switch Q1 turned on.

[0053] After obtaining the first time and the second time, the delay time length corresponding to the 50Ω delay line can be designed to be at least the time difference corresponding to the second time minus the first time.

[0054] By designing the delay length of the 50Ω delay line, it is ensured that when the power of the RF signal exceeds the first power, the RF signal is attenuated or reduced before reaching the amplifier, so that the amplifier LNA can be protected in real time and effectively before the RF signal arrives.

[0055] The first time and the second time can be obtained by using an oscilloscope with a detection probe and a pulse signal generator. Set the detection probe at the RF_IN output port and the 50Ω delay line input port respectively, set the oscilloscope at the corresponding position of the switch Q1, and use the pulse signal generated by the pulse signal generator to simulate the RF signal passing through the corresponding components, so as to determine the first time and the second time respectively.

[0056] As described above, the limiting element is used to start the attenuation limiting function after the switch Q1 is turned on, and attenuate the power of the first RF signal delayed output by the delay element. However, different limiting elements have different corresponding limiting thresholds, resulting in different limiting capabilities of different limiting elements, and the attenuated power range is limited.

[0057] Optionally, the limiting element attenuates the power of the delayed output first radio frequency signal, specifically including: attenuating the power of the first radio frequency signal according to a limiting threshold value corresponding to the limiting element.

[0058] For example, if the limiting threshold value of a certain type of limiting tube is 20dBm, it means that it can attenuate the power of the RF signal by 20dBm at most. Usually, the limiting threshold value of the limiting tube is 10-20dBm.

[0059] Since the limiting element has a certain limiting capability, if the power of the RF signal to be sent to the amplifier is very high, after the limiting element attenuates the RF signal power to a certain power according to its own limiting capability, the attenuated RF signal may still exceed the amplifier's tolerance power, thereby causing damage to the amplifier.

[0060] In this regard, in one embodiment of the present application, a new attenuation element is introduced to further perform power attenuation processing on the first radio frequency signal after attenuation by the limiting tube.

[0061] Optionally, the attenuation unit also includes a second switch and a capacitor module, the first end of the second switch is connected to the output end of the signal conversion element, the second end of the second switch is grounded, and the third end of the second switch is connected to the first end of the capacitor module; the second end of the capacitor module is connected to the output end of the delay element, and the third end of the capacitor module is connected to the input end of the amplifier; wherein, when the output voltage reaches a second preset voltage, the second switch is turned on and triggers the first end of the capacitor module to be short-circuited to the ground, and the second preset voltage is greater than the first preset voltage.

[0062] like Figure 2 As shown, the second switch includes a switch Q2, resistors R4 and R5, and the switch Q2 may be a MOS tube. One end of the switch Q2 is connected to the output end of the detector diode D1 via the resistor R5 and the operational amplifier, the other end of the switch Q2 is grounded, and another end of the switch Q2 is connected to the capacitor module. The switch Q2 is turned on when the voltage value of the received voltage signal reaches the second preset voltage.

[0063] The switch Q2 is grounded when turned on, causing the capacitor module connected to one end of the switch Q2 to be short-circuited to the ground, thereby forming a low impedance to further attenuate the power of the first RF signal attenuated by the limiting tube.

[0064] Optionally, the capacitor module includes a first capacitor and a second capacitor connected in series, the first end of the first capacitor is connected to the output end of the delay element, the second end of the first capacitor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the input end of the amplifier, and the third end of the second switch is connected to the second end of the first capacitor or the first end of the second capacitor.

[0065] In one embodiment, the capacitor module performs secondary power attenuation on the first RF signal attenuated by the limiting element, specifically including: when the second switch is turned on, the second end of the first capacitor and the first end of the second capacitor are short-circuited to the ground to form a low impedance, and the first RF signal attenuated by the limiting element is reflectively attenuated.

[0066] like Figure 2 As shown, the capacitor module includes a first capacitor C3 and a second capacitor C4 connected in series, the output end of the second capacitor C4 is connected to the input end of the amplifier LNA, one end of the first capacitor C3 is connected to the output end of the 50Ω delay line, and the other end of the first capacitor C3 is connected to one end of the switch Q2.

[0067] As described above, when the output voltage of the output end of the signal conversion element reaches the second preset voltage, the second switch is turned on, the second preset voltage is greater than the first preset voltage, the second power corresponding to the second preset voltage is less than the tolerance power of the amplifier, and the first power is less than the second power.

[0068] That is to say, when the RF signal power output from the RF signal output port is less than the first power, the RF signal power will not cause damage to the amplifier, and at this time the first switch will not be turned on and the power of the RF signal will be attenuated; when the RF signal power output from the RF signal output port is greater than the first power and less than the second power, the higher RF signal power will cause damage to the amplifier, and at this time only the first switch can be turned on and the power of the RF signal can be attenuated using a limiting element; when the RF signal power output from the RF signal output port is greater than the second power, the higher RF signal power will cause damage to the amplifier, and at this time both the first switch and the second switch are turned on, and the power of the RF signal is multiple times attenuated using a limiting element and a capacitor module.

[0069] In the embodiment where the attenuation unit includes a first switch, a limiting element, a second switch and a capacitor module, the resistors Rf and Rg of the operational amplifier, the resistors R2 and R3 of the first switch and the resistors R4 and R5 of the second switch are determined based on the on and off states of the switches Q1 and Q2 and the first preset voltage corresponding to the on state of the switch Q1 and the second preset voltage corresponding to the on state of the switch Q2. After the first and second preset voltage values ​​are fixed, the ratio of the resistance values ​​is also fixed accordingly.

[0070] Optionally, the difference between the tolerable power of the amplifier and the second power is 5-20 dBm, and the difference between the second power and the first power is 5-30 dBm.

[0071] When the voltage value of the voltage signal converted from the power of the second RF signal reaches the second preset voltage, both switch Q1 and switch Q2 are turned on. After switch Q1 is turned on, the attenuation and amplitude limiting function of the amplitude limiting tube connected to switch Q1 is immediately triggered and enabled, that is, the power amplitude of the first RF signal delayed output by the delay element subsequently received can be limited and attenuated. After switch Q2 is turned on, capacitors C3 and C4 connected to switch Q2 are grounded, and the first RF signal attenuated by the amplitude limiting tube is again reflectively attenuated.

[0072] In the above embodiment, the second preset time length of the 50Ω delay line delay is determined based on the first time length required for the first RF signal to reach the input end of the 50Ω delay line and the third time length required for the voltage signal corresponding to the second RF signal to turn on both switches Q1 and Q2. When the delay time reaches the second preset time length, the output end of the delay element outputs the RF signal, and the second preset time length is not less than the first preset time length.

[0073] The first time may also be the time required for the RF signal RF_IN to reach the input end of the 50Ω delay line after passing through the filter Filter and the microstrip coupler from the RF signal output port. The third time may also be the time required for the RF signal RF_IN to pass through the filter Filter, the microstrip coupler, the attenuator ATT, the detection diode D1, the amplifier, the switch Q1, the switch Q2 from the RF signal output port and make both switches Q1 and Q2 turned on, that is, the maximum value of the time required to turn on switch Q1 and the time required to turn on switch Q2.

[0074] The calculation method of the preset delay time length in this embodiment can refer to Figure 4 Examples, such as Figure 4 As shown, the time required for the RF signal RF_IN to reach the input end of the 50Ω delay line from the RF signal output port through the filter Filter and the microstrip coupler is the first time t1, and the RF signal RF_IN passes through the filter Filter, the microstrip coupler, the attenuator ATT, the detection diode D1, the amplifier, the switch Q1, and the switch Q2 from the output port. The maximum value of the time required for the switches Q1 and Q2 to be turned on is taken as the third time t2.

[0075] After obtaining the first time t1 and the third time t2, the delay time length corresponding to the 50Ω delay line can be designed to be at least the time difference (t1-t2) corresponding to the third time t2 minus the first time t1.

[0076] By designing the delay length of the 50Ω delay line, it is ensured that when the RF signal exceeds the second power, the RF signal is attenuated or reduced before reaching the capacitors C3 and C4, so that the amplifier LNA can be effectively protected in real time before the RF signal arrives.

[0077] The first time t1 and the third time t2 can also be obtained by using an oscilloscope with a detection probe and a pulse signal generator. Set the detection probe at the RF_IN output port and the 50Ω delay line input port respectively, set the oscilloscope at the corresponding positions of switches Q1 and Q2 respectively, and use the pulse signal generated by the pulse signal generator to simulate the RF signal along the Figure 4 The two dashed line paths shown pass through corresponding elements, thereby respectively determining the first time t1 and the third time t2.

[0078] After the received high-power RF signal turns on both switches Q1 and Q2, the switch Q1 and the limiter tube are first used to perform power attenuation processing on the delayed output first RF signal. The attenuation method is as described above and will not be repeated here. Then, the switch Q2 and capacitors C3 and C4 are used to attenuate the first RF signal attenuated by the limiter tube again.

[0079] Specifically, a conventional RF signal is transmitted on a 50Ω impedance line. When the switch Q2 is turned on, the endpoint between the first capacitor C3 and the second capacitor C4 will be short-circuited to the ground. At this time, the impedance changes from 50Ω to a very low impedance, such as a few milliohms to tens of milliohms, which will form reflective attenuation.

[0080] Therefore, when the switch Q2 is turned on, the impedance between the first capacitor C3 and the second capacitor C4 is in an extremely low impedance state, which forms a certain reflective attenuation on the first RF signal. The magnitude of the attenuation power is related to the device model selection of the switch Q2. Usually, the first capacitor C3 and the second capacitor C4 are short-circuited to the ground, which can form a power attenuation of 10-30dBm.

[0081] In this way, through the attenuation unit including the first switch and the limiting tube, the second switch and the capacitor module, the first RF signal delayed by the delay element can be subjected to multiple superimposed power attenuation, so that the power of the high-power RF signal can be attenuated to below the amplifier's tolerance power before being input to the amplifier, thereby avoiding damage to the amplifier. After the power-attenuated RF signal is processed by the amplifier, the RF signal RF_OUT is output.

[0082] The radio frequency signal after power attenuation avoids damage to the amplifier and does not affect the quality of the radio frequency signal and subsequent demodulation of the radio frequency signal.

[0083] Reference now Figure 5 , Figure 5 It is a circuit structure diagram of the protection circuit of the second embodiment of the present application.

[0084] and Figure 2 The difference between the embodiments is that Figure 5 In the embodiment of the present invention, the signal separation element may include a coupling capacitor. The various processes implemented by other elements are similar to those Figure 2 To avoid repetition, they are not described here again.

[0085] The following will be combined Figure 2 and Figure 6 The overall operation process of the protection circuit of the embodiment of the present application is described. Figure 6 It is a schematic diagram of the operation flow of the protection circuit of an embodiment of the present application.

[0086] exist Figure 6 In the embodiment, the power threshold A is a first power corresponding to a first preset voltage that can trigger the switch Q1 to turn on, and the power threshold B is a second power corresponding to a second preset voltage that can trigger the switch Q2 to turn on.

[0087] Figure 6 According to the input power of the radio frequency signal RF_IN, three cases are described.

[0088] The first method: if the input power of the radio frequency signal RF_IN to be sent to the amplifier exceeds the power threshold A but does not exceed the power threshold B, the method includes the following steps:

[0089] Step 102, passing the second radio frequency signal separated from the radio frequency signal RF_IN by the microstrip coupler through a coupler, an attenuator, a detector diode, and an operational amplifier;

[0090] Step 104, after the first RF signal separated from the RF signal RF_IN by the microstrip coupler passes through the 50Ω delay line, before reaching the capacitor C3, the voltage signal corresponding to the second RF signal triggers the switch Q1 to turn on;

[0091] Step 106, the turned-on switch Q1 causes the limiter tube to respond, and limits and attenuates the power amplitude of the first RF signal exceeding the power threshold A before reaching the capacitor C3;

[0092] Step 108: The input power of the RF signal entering the amplifier LNA does not exceed the threshold A, and the amplifier LNA is not damaged.

[0093] The second type: if the input power of the radio frequency signal RF_IN to be sent to the amplifier does not exceed the power threshold A, it includes:

[0094] In step 110, switches Q1 and Q2 are both turned off, the limiter tube does not work, and the power of the delayed output first RF signal is not attenuated.

[0095] Step 108: The input power of the RF signal entering the amplifier LNA does not exceed the threshold A, and the amplifier LNA is not damaged.

[0096] The third method: if the input power of the radio frequency signal RF_IN to be sent to the amplifier exceeds the power threshold B, the following steps are included:

[0097] Step 112, passing the second radio frequency signal separated from the radio frequency signal RF_IN by the microstrip coupler through a coupler, an attenuator, a detector diode, and an operational amplifier;

[0098] Step 114, after the first RF signal separated from the RF signal RF_IN by the microstrip coupler passes through the 50Ω delay line, before reaching the capacitors C3 and C4, the voltage signal corresponding to the second RF signal triggers the switches Q1 and Q2 to turn on;

[0099] Step 116, the turned-on switch Q1 causes the limiter to respond, and Q2 is turned on to form a low impedance at the endpoint between the capacitors C3 and C4, thereby limiting and attenuating the power amplitude of the first RF signal exceeding the power threshold B before reaching the capacitors C3 and C4;

[0100] Step 108: The input power of the RF signal entering the amplifier LNA does not exceed the threshold A, and the amplifier LNA is not damaged.

[0101] In an embodiment of the present application, the protection circuit includes an amplifier, a signal separation element, a delay element, a signal conversion element and an attenuation unit. When the output voltage of the output end of the signal conversion element reaches a preset threshold, the attenuation unit is turned on and attenuates the radio frequency signal delayed output by the output end of the delay element, thereby triggering the protection circuit and responding in time before the high-power radio frequency signal reaches the amplifier, attenuating the high-power signal, and being able to protect the amplifier from damage by the high-power radio frequency signal in real time and effectively.

[0102] At the same time, when the RF signal power is lower than the predetermined power, the protection circuit does not respond and does not attenuate the power of the RF signal, which has little impact on the amplifier, and the amplifier can normally receive the low-power RF signal.

[0103] Optional, such as Figure 7 As shown, an embodiment of the present application further provides an electronic device 900, comprising the protection circuit described in the above embodiment of the present application.

[0104] Figure 7 The hardware structure diagram of an electronic device 900 for implementing an embodiment of the present application is shown. The electronic device 900 includes, but is not limited to, components such as a radio frequency unit 901, a network module 902, an audio output unit 903, an input unit 904, a sensor 905, a display unit 906, a user input unit 907, a protection circuit 102, a memory 908, and a processor 909.

[0105] The protection circuit 102 may correspond to the above Figures 1 to 6 The protection circuit of any embodiment can achieve the same technical effect, and will not be described again here to avoid repetition.

[0106] Those skilled in the art will appreciate that the electronic device 900 may also include a power source (such as a battery) for supplying power to each component, and the power source may be logically connected to the processor 909 through a power management system, thereby implementing functions such as managing charging, discharging, and power consumption management through the power management system. Figure 6 The electronic device structure shown in the figure does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently, which will not be described in detail here.

[0107] The processor is a processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0108] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0109] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0110] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A protection circuit, characterized in that: The circuit includes an amplifier, a signal separation element, a delay element, a signal conversion element and an attenuation unit. The input end of the signal separation element is connected to the RF signal output port, the first output end of the signal separation element is connected to the input end of the delay element, the second output end of the signal separation element is connected to the input end of the signal conversion element; the output end of the delay element is connected to the input end of the amplifier; The attenuation unit is connected between the output end of the delay element and the output end of the signal conversion element; Wherein, when the output voltage of the output end of the signal conversion element reaches a preset threshold, the attenuation unit is turned on and performs attenuation processing on the radio frequency signal delayed output from the output end of the delay element; The attenuation unit comprises a first switch and a limiting element, A first end of the first switch is connected to the output end of the signal conversion element, a second end of the first switch is connected to the first end of the amplitude limiting element, and a third end of the first switch is grounded; The second end of the amplitude limiting element is connected to the output end of the delay element, Wherein, when the output voltage reaches a first preset voltage, the first switch is turned on and triggers the limiting element to be enabled; The attenuation unit further includes a second switch and a capacitor module, A first end of the second switch is connected to the output end of the signal conversion element, a second end of the second switch is grounded, and a third end of the second switch is connected to the first end of the capacitor module; The second end of the capacitor module is connected to the output end of the delay element, and the third end of the capacitor module is connected to the input end of the amplifier; Wherein, when the output voltage reaches a second preset voltage, the second switch is turned on and triggers the first end of the capacitor module to be short-circuited to the ground, and the second preset voltage is greater than the first preset voltage.

2. The circuit according to claim 1, characterized in that When the delay time reaches a first preset time length, the output end of the delay element outputs the radio frequency signal.

3. The circuit according to claim 1, characterized in that The capacitor module includes a first capacitor and a second capacitor connected in series, the first end of the first capacitor is connected to the output end of the delay element, the second end of the first capacitor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the input end of the amplifier, and the first end of the second switch is connected to the second end of the first capacitor or the first end of the second capacitor.

4. The circuit according to claim 3, characterized in that When the delay time reaches a second preset time length, the output end of the delay element outputs the radio frequency signal, and the second preset time length is not less than the first preset time length.

5. The circuit according to any one of claims 1 to 4, characterized in that The signal conversion element is a detector diode, and the circuit further includes: The attenuation element is connected between the second output terminal of the signal separation element and the input terminal of the detection diode.

6. The circuit according to claim 1, characterized in that The signal separation element includes a microstrip coupler or a coupling capacitor.

7. An electronic device, characterized in that: The invention comprises a protection circuit as claimed in any one of claims 1 to 6.

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