A constant power or constant gain mode switchable power amplifier control circuit

Abstract

The application relates to the field of communication, in particular to a constant-power or constant-gain mode switchable power amplifier control circuit, which comprises an amplification link and an adjusting circuit; the amplification link comprises a preamplification stage, a signal attenuator, a driving amplification stage, a final-stage power amplifier and a signal coupler which are sequentially connected from a signal input end to a signal output end; the adjusting circuit is used for sending a gain adjusting signal to the signal attenuator and maintaining the stability of the amplification link; the application solves the problems that microwave power amplifier equipment needs to be switched in different constant-power or constant-gain working modes, the equipment power amplifier enters a deep saturation working state, the signal quality deteriorates, the reliability of the equipment is reduced and the service life is shortened; the application facilitates the user to switch the working mode in different use scenes, protects the output signal quality of the equipment power amplifier from deterioration, improves the reliability of the equipment and prolongs the service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication, more particularly, to a power amplifier control circuit with switchable constant power or constant gain mode. BACKGROUND

[0002] With the launch of China Star 16 on April 12, 2017, China has entered the era of high-throughput satellite mobile communication, and microwave communication equipment is widely used. In satellite communication applications, microwave power amplifiers are essential equipment.

[0003] The existing microwave power amplifier equipment generally has fixed gain in operation, and the user can modify the gain parameter. However, in some application scenarios, the user wants the output to remain constant power when the input signal strength varies within a certain range, which requires the application of automatic power control technology (APC). It is a direction to be studied in the field to enable the microwave power amplifier to switch between constant gain and constant power modes to meet different user requirements for signal strength and signal quality.

[0004] In addition to the switching of different working modes of the microwave power amplifier, how to protect the device power amplifier in the constant gain working mode when the input signal is continuously overdriven. The device power amplifier will enter a saturated working state or even a deep saturated working state. The signal quality of the power amplifier in the saturated state will deteriorate; the signal quality of the power amplifier in the deep saturated state will deteriorate even more, and the reliability and service life of the device will be reduced.

[0005] In addition to meeting the switching of different working modes of the microwave power amplifier, how to solve the above problems also includes protecting the power amplifier device from entering a saturated or deep saturated state to avoid deterioration of signal quality and reduction of device reliability and service life. SUMMARY

[0006] The present application aims to overcome at least one of the above-mentioned defects (shortcomings) of the prior art, and provides a power amplifier control circuit with switchable constant power or constant gain mode, which is used to solve the problem that the microwave power amplifier device needs to be switched between different working modes of constant power or constant gain, and when the input signal is overdriven, the device power amplifier enters a deep saturated working state, thereby causing deterioration of signal quality and reduction of device reliability and service life.

[0007] The technical solution adopted by the present application is a power amplifier control circuit with switchable constant power or constant gain mode, which comprises an amplification link and a regulation circuit. The amplification link comprises a preamplification stage, a signal attenuator, a drive amplification stage, a final power amplifier, and a signal coupler connected in sequence from a signal input end to a signal output end. The regulation circuit is used to send a gain regulation signal to the signal attenuator and maintain the stability of the amplification link.

[0008] It is beneficial to amplify the weak signal source of the signal input end through the amplification link to drive the load to work normally; it is beneficial to realize the switching of the working mode of the device power amplifier through the adjusting circuit, and the device power amplifier can be protected from the influence when the signal is over-excited in the constant gain mode, thereby avoiding the deterioration of the signal quality of the device power amplifier and the reduction of the reliability and service life of the device.

[0009] The adjusting circuit comprises a mode switching switch, a constant power adjusting circuit and a constant gain adjusting circuit, the mode switching switch is used to switch the connection of the constant gain adjusting circuit or the constant power adjusting circuit, the constant gain adjusting circuit sets a fixed attenuation value through the signal attenuator, and the constant power adjusting circuit sets a corrected attenuation value through the signal attenuator.

[0010] It is beneficial to realize the switching of the constant gain working mode or the constant power working mode through the connection of the mode switching switch and different adjusting circuits, to meet the application flexibility of different scenes of users; it is beneficial to avoid the power amplifier from entering a deep saturation state when the input signal is over-excited, thereby ensuring the signal quality and improving the reliability and life of the device.

[0011] The constant gain adjusting circuit comprises a fixed gain setting end, the fixed gain setting end is connected to the signal attenuator through the mode switching switch and inputs an attenuation setting value matched with a fixed gain setting value.

[0012] After the fixed gain setting value is set, the loop gain is fixed, and the output power follows the change of the strength of the input signal, and the stronger the input signal is, the greater the output power is.

[0013] The constant power adjusting circuit comprises a detection amplification module, an automatic feedback module and an addition module, the input end of the detection amplification module is connected to the signal coupler and outputs a power error value; the automatic feedback module is connected between the detection amplification module and the addition module and outputs the input power error value as a gain adjustment value; the output end of the addition module outputs a corrected gain control value, which is connected to the signal attenuator through the mode switching switch; and the signal attenuator is used to receive a corrected attenuation value matched with the corrected gain control value.

[0014] The constant power regulation circuit is beneficial to outputting the correction value of the attenuation value of the signal attenuator, so that the input signal fluctuates within the amplitude limited by the input range, the output power remains unchanged, and the amplifier will not enter the saturation state; the detection and amplification module is beneficial to realizing the detection and extraction of the output power, amplifying the output power error value after comparison with the output power setting value, and improving the response accuracy; the automatic feedback module is beneficial to quickly converting the amplified output power error value into a gain adjustment value, improving the response speed and stability; and the addition module is beneficial to adding the gain adjustment value and the fixed gain setting value to obtain the corrected gain control value that can maintain the signal quality, thereby enhancing the stability of the regulation circuit under the premise of ensuring the full input range adaptability.

[0015] The detection and amplification module includes an output power detector, a differential amplifier and an output power setting end. The input end of the output power detector receives the sampled output power of the signal coupler and outputs a detected power value to the differential amplifier. The input end of the differential amplifier is connected to the output end of the output power detector and the output power setting end, and is used to amplify the difference between the detected power value and the output power setting value of the output power setting end, and output a power error value.

[0016] The output power detector is beneficial to identifying and extracting the output power and outputting the detected power. The differential amplifier is beneficial to amplifying the power error value formed between the detected power and the output power setting value, so as to improve the response accuracy.

[0017] The automatic feedback module includes a PID circuit. The input end of the PID circuit is connected to the output end of the differential amplifier, and is used to adjust the power error signal response curve and output a gain adjustment value. The addition module includes an adder and a fixed gain setting end. The input end of the adder module is connected to the output end of the PID circuit and the fixed gain setting end, and is used to add the input gain adjustment value and the fixed gain setting value of the fixed gain setting end, and output a corrected gain control value.

[0018] The PID circuit is beneficial to adjusting the power error value, so that the output power is not unstable caused by too large or too fast amplitude in the adjustment process, and is quickly adjusted to the required gain control value. The adder is beneficial to adding the power error adjustment value and the fixed gain setting value, so as to reduce the degree of overshoot of the output power when the input signal changes from zero to a certain value.

[0019] When the detected power is greater than the output power setting value, the differential amplifier outputs a negative voltage, which, after being processed by the PID circuit, generates a gain adjustment value, which, after being added to the fixed gain setting value, controls the signal attenuator to reduce the gain; when the detected power is less than the output power setting value, the differential amplifier outputs a positive voltage, which, after being processed by the PID circuit, generates a gain adjustment value, which, after being added to the fixed gain setting value, controls the signal attenuator to increase the gain; the PID circuit is used to adjust the power error signal response curve and maintain the stability of the gain adjustment value.

[0020] The control logic is beneficial for the differential amplifier to output voltages in opposite directions according to the difference between the detected power and the output power setting value, for the PID circuit to generate a gain adjustment value, and for the fixed gain setting value to be added to the gain adjustment value to form different corrected gain control values, so that the adjustment circuit quickly pulls the output power to be equal to the output power setting value through the corrected gain control value and maintains stability, thereby improving the rapidity and stability of the adjustment circuit in adjusting the signal of the amplification link.

[0021] The adjustment circuit further comprises a polarity adjustment circuit connected between the mode switching switch and the signal attenuator, used to adjust the positive and negative polarity of the output signal of the mode switching switch and match the control voltage polarity and control level range of the signal attenuator.

[0022] The polarity adjustment circuit is beneficial for polarity adjustment and level adaptation of the fixed gain setting value or the corrected gain control value to match the control level range requirement of the signal attenuator.

[0023] Further comprising a protection circuit, the protection circuit comprising a maximum power protection module, a gain discrimination module and a single-chip microcomputer controller, the maximum power protection module and the gain discrimination module being connected in parallel to the single-chip microcomputer controller, the single-chip microcomputer controller sending a switching signal to the mode switching switch according to the working state of the gain discrimination module and the maximum power protection module, and the mode switching switch receiving the signal to switch to the constant power adjustment circuit or the constant gain adjustment circuit.

[0024] The single-chip microcomputer controller in the protection circuit is beneficial for automatic switching of the mode switching switch; the maximum power protection module is beneficial for judging whether the input signal is over-excited and causing the single-chip microcomputer controller to send a switching signal to switch the constant gain adjustment circuit to the constant power adjustment circuit; and the maximum power protection module is beneficial for setting the output power to a constant value to output constant power, thereby maintaining the output power at the rated power value, avoiding over-excited input signals outputting too much power to cause the power amplifier to enter a saturated or deep saturated working state, and achieving the effects of improving the reliability of the power amplifier and prolonging the service life of the power amplifier.

[0025] The gain discrimination module comprises a gain value comparator, input ends of the gain value comparator being connected to output ends of the adder and the fixed gain setting end at the same time, for judging the size of the corrected gain control value and the fixed gain setting value, and outputting a signal to the single-chip microcomputer controller; the maximum power protection module comprises a power value comparator, input ends of the power value comparator being connected to output ends of the output power detector and the maximum power setting end at the same time, for judging the size of the detected power value and the maximum power setting value, and outputting a signal to the single-chip microcomputer controller.

[0026] The corrected gain control value at the output end of the adder and the fixed gain setting value are compared through the gain value comparator, so as to judge whether the input signal is over-excited; the detected power at the output end of the output power detector and the maximum power setting value are compared through the power value comparator, so as to judge whether the output power is too large; the connection between the single-chip microcomputer controller and the mode switching switch, the gain value comparator and the power value comparator is beneficial to switching to the constant power mode when the input signal is over-excited and maintaining the stability of the output power through the maximum power setting value, so as to protect the output power of the amplification link from being too large, causing the deterioration of the signal quality and affecting the reliability and service life of the equipment power amplifier.

[0027] Compared with the prior art, the beneficial effects of the present application are that the user can switch the microwave power amplifier equipment to different working modes in different use scenarios, and protect the equipment power amplifier from entering a deep saturation working state when the input signal is over-excited, so as to avoid the deterioration of the output signal quality and improve the reliability and prolong the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The circuit control logic diagram of the present application.

[0029] The output power detector 1, the differential amplifier 2, the PID circuit 3, the adder 4, the mode switching switch 5, the polarity adjusting circuit 6, the signal attenuator 7, the power value comparator 8, the gain value comparator 9 and the single-chip microcomputer controller 10 are shown in the figure. DETAILED DESCRIPTION

[0030] The drawings of the present application are only used for illustrative description, and cannot be understood as a limitation of the present application. In order to better illustrate the following embodiments, some components in the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0031] Embodiment 1

[0032] As Figure 1As shown, the embodiment provides a constant power or constant gain mode switchable power amplifier control circuit, which comprises an amplification link and a regulating circuit, the amplification link comprises a pre-amplification stage, a signal attenuator 7, a drive amplification stage, a final power amplification stage and a signal coupler, which are connected in sequence from a signal input end to a signal output end, the regulating circuit is used to send a gain regulating signal to the signal attenuator 7 and maintain the stability of the amplification link.

[0033] In the embodiment, the pre-amplification stage module is used to amplify the input signal to a certain amplitude to cooperate with the signal attenuator 7 to regulate the gain of the entire amplification link; the signal attenuator 7 is used to regulate the gain of the entire amplification link; the drive amplification stage is used to further amplify the signal to a certain amplitude to meet the input amplitude requirement of the final power amplification stage; the final power amplification stage is used to further amplify the signal to the rated output power of the device power amplifier; and the signal coupler is used to proportionally couple the output power signal for sampling the output power.

[0034] In the embodiment, the input end of the regulating circuit is connected to the signal coupler, and the output end of the regulating circuit is connected to the signal attenuator 7, and the signal change of the regulating circuit controls the signal change of the amplification link.

[0035] The regulating circuit comprises a mode switch switch 5, a constant power regulating circuit and a constant gain regulating circuit, the mode switch switch 5 is used to switch the connection of the constant gain regulating circuit or the constant power regulating circuit, the constant gain regulating circuit sets a fixed attenuation value through the signal attenuator 7, and the constant power regulating circuit sets a corrected attenuation value through the signal attenuator 7.

[0036] In the embodiment, the mode switch switch 5 is used for switching the working mode of the device, when it is connected to the constant power regulating circuit, the device is in the constant power mode to ensure the quality of the output signal, and when it is connected to the constant gain regulating circuit, the device is in the constant gain mode to meet the use requirement of the user.

[0037] The constant gain regulating circuit comprises a fixed gain setting end, the fixed gain setting end is connected to the signal attenuator 7 through the mode switch switch 5 and inputs an attenuation setting value matched with the fixed gain setting value.

[0038] In the embodiment, the constant gain adjusting circuit comprises a fixed gain setting end, a mode switching switch 5 and a polarity adjusting circuit 6. The mode switching switch 5 is directly connected to the fixed gain setting end. The fixed gain setting value is transmitted to the input end of the polarity adjusting circuit 6 through the mode switching switch 5, and then is matched and output to the input end of the signal attenuator 7 of different types after being adjusted in positive and negative polarity. Meanwhile, the signal amplification is adjusted to meet the amplitude requirement of the control signal of the signal attenuator 7.

[0039] The constant power adjusting circuit comprises a detection amplification module, an automatic feedback module and an addition module. The input end of the detection amplification module is connected to the signal coupler, and outputs a power error value. The automatic feedback module is connected between the detection amplification module and the addition module, and outputs the input power error value as a gain adjusting value. The output end of the addition module outputs a corrected gain control value, which is connected to the signal attenuator 7 through a mode switching switch. The signal attenuator 7 is used to receive a corrected attenuation value matched with the corrected gain control value.

[0040] In the embodiment, the constant power adjusting circuit calculates and amplifies the difference between the real-time output power and the target power through the detection amplification module to obtain a power error value. The automatic feedback module performs closed-loop control processing on the amplified difference, so that the real-time output power in the circuit is steadily reduced to the target power through the gain adjusting value. The addition module adds the fixed gain setting value and the gain adjusting value, and outputs a corrected gain control value, so that the output power is constant when the input signal changes within a certain range.

[0041] The detection amplification module comprises an output power detector 1, a differential amplifier 2 and an output power setting end. The input end of the output power detector 1 receives the sampled output power of the signal coupler, and outputs a detection power value to the differential amplifier 2. The input end of the differential amplifier 2 is connected to the output end of the output power detector 1 and the output power setting end, and is used to amplify the difference between the detection power value and the output power setting value of the output power setting end, and output a power error value.

[0042] In the embodiment, the output power detector 1 is used to detect the output power coupling signal, and then the differential amplifier 2 and the output power setting value are differentially amplified. If the detection power is greater than the output power setting value, the differential amplification output is a negative voltage, and vice versa. The differential amplifier 2 is used to amplify the difference between the detection power signal and the output power setting value, and output a power error value, so as to prepare for the real-time adjustment of the output power in the next step.

[0043] The automatic feedback module comprises a PID circuit 3, an input end of the PID circuit 3 being connected to an output end of the differential amplifier 2, for adjusting a power error signal response curve and outputting a gain adjustment value; the adding module comprises an adder 4 and a fixed gain setting end, an input end of the adder module being connected to an output end of the PID circuit 3 and the fixed gain setting end at the same time, for adding the input gain adjustment value and a fixed gain setting value of the fixed gain setting end and outputting a corrected gain control value.

[0044] In the embodiment, the PID circuit 3 is a circuit comprising a proportional control algorithm, an integral control algorithm and a differential control algorithm. When the input end of the PID circuit 3 inputs a power error value, the proportional control algorithm is used to make the error value between the current power value and the target power value smaller and smaller, until a steady-state error occurs; the integral control algorithm is used to make the previous proportional increments be accumulated to eliminate the steady-state error; and the differential control algorithm is used to make the current power error value approach the future power error value and reduce control oscillation.

[0045] In the embodiment, the gain adjustment value is used to ensure the stability of the adjusting circuit and the amplification link in real-time adjustment; and the addition of the gain adjustment value and the fixed gain setting value is used to limit the gain adjustment range, so that when the input signal changes from nothing to something, the output will not have a too large power impact.

[0046] When the detected power is greater than the output power setting value, the differential amplifier 2 outputs a negative voltage, and after being processed by the PID circuit 3, a negative gain adjustment value is generated, which is added to the fixed gain setting value to control the signal attenuator 7 to reduce the gain; when the detected power is less than the output power setting value, the differential amplifier 2 outputs a positive voltage, and after being processed by the PID circuit 3, a positive gain adjustment value is generated, which is added to the fixed gain setting value to control the signal attenuator 7 to increase the gain; the PID circuit 3 is used to adjust the power error signal response curve and maintain the stability of the gain adjustment value.

[0047] In the embodiment, the adjustment circuit includes an APC (Automatic Power Control) process. When the detected power is greater than the output power setting value, the differential amplifier 2 outputs a negative voltage, and the power error value output by the differential amplifier 2 is converted into a negative gain adjustment value by the PID circuit 3, and then added to the fixed gain setting value, so that the gain control value is reduced, and the control signal attenuator 7 reduces the gain (increases the attenuation value). Conversely, when the detected power is less than the output power setting value, the differential amplifier 2 outputs a positive voltage, and the power error value output by the differential amplifier 2 is converted into a positive gain adjustment value by the PID circuit 3, and then added to the fixed gain setting value, so that the gain control value is increased, and the control signal attenuator 7 increases the gain (reduces the attenuation value). Under the adjustment of the loop parameters of the PID circuit 3, the detected power is quickly pulled to be equal to the output power setting value and maintained stable.

[0048] The adjustment circuit further includes a polarity adjustment circuit 6 connected between the mode switching switch 5 and the signal attenuator 7, for adjusting the positive and negative polarity of the signal output by the mode switching switch 5, and matching the control voltage polarity and control level range of the signal attenuator 7.

[0049] In the embodiment, in the constant power operation mode, the polarity adjustment circuit 6 adjusts the polarity and level of the signal from the mode switching switch 5, so as to match the control voltage polarity and control level range of the signal attenuator 7. In the constant gain operation mode, the polarity adjustment circuit 6 adjusts the polarity and level of the fixed gain setting value, so as to match the control voltage polarity and control level range of the signal attenuator 7.

[0050] The protection circuit further includes a maximum power protection module, a gain discrimination module and a single-chip microcomputer controller 10. The maximum power protection module and the gain discrimination module are connected in parallel to the single-chip microcomputer controller 10. The single-chip microcomputer controller 10 sends a switching signal to the mode switching switch 5 according to the working state of the gain discrimination module and the maximum power protection module. The mode switching switch 5 receives the signal and switches to the constant power adjustment circuit or the constant gain adjustment circuit.

[0051] In the embodiment, when the input signal in the constant gain mode is over-excited, the device can be switched to the maximum power protection mode to ensure that the output power of the power amplifier does not exceed saturation. When the maximum power protection mode is entered, the output power setting value is set to the maximum power setting value.

[0052] The gain discrimination module comprises a gain value comparator 9, the input end of which is connected to the output end of the adder 4 and the fixed gain setting end, for judging the size of the corrected gain control value and the fixed gain setting value, and outputting a signal to the single-chip microcomputer controller 10; the maximum power protection module comprises a power value comparator 8, the input end of which is connected to the output end of the output power detector 1 and the maximum power setting end, for judging the size of the detected power value and the maximum power setting value, and outputting a signal to the single-chip microcomputer controller 10.

[0053] In this embodiment, the power value comparator 8 continuously compares the detected power with the maximum power setting value, when the detected power is greater than the maximum power setting value (the input signal is over-excited), the output end of the power value comparator 8 changes from high level to low level, triggering the single-chip microcomputer controller 10 to interrupt, the single-chip microcomputer controller 10 connects the mode switching switch 5 to the output end of the adder 4, the device enters the maximum power protection state, and the output power setting value is locked at the maximum power setting value.

[0054] In the maximum power protection state, the gain value comparator 9 continuously compares the corrected gain control value (current gain value) output by the adder 4 with the fixed gain setting value, when the corrected gain control value is greater than the fixed gain setting value (the input signal returns to normal), the output end of the gain value comparator 9 changes from high level to low level, triggering the single-chip microcomputer controller 10 to interrupt, the single-chip microcomputer controller 10 connects the mode switching switch 5 to the fixed gain setting end, the device exits the maximum power protection state, and returns to the constant gain working mode.

[0055] Embodiment 2

[0056] In this embodiment, the trigger condition of the protection circuit depends on the size of the input signal, when the input signal is less than -8.5dBm, the protection circuit is not triggered to start, and when the input signal is greater than -8.5dBm, the protection circuit is triggered to start.

[0057] In this embodiment, the user can set the device to the constant gain mode, the user can set the gain value, for example, the fixed gain setting value is 65dB, the maximum power setting value and the output power setting value are both 56.5dBm (447W). In this state, as long as the input signal is less than -8.5dBm, the maximum power protection will not be triggered. In this mode, the power amplifier gain is fixed, for example, when the input signal is -10dBm, the output is -10+65=55dBm, and when the input is -15dBm, the output is -15+65=50dBm.

[0058] In this embodiment, when the adjustment circuit is in constant power operation mode, the output power setting value is set to 56dBm (400W), the fixed gain setting value is 65dB, when the input signal is -9dBm, the output power detection value is equal to -9+65=56dBm when working stably, the gain adjustment value output by the PID is 0, the loop gain = 65+0=65dB. When the input signal jumps from -9dBm to -8dBm instantaneously, due to the stability of the loop gain, the output power detection value is equal to -8+65=57dBm (500W), the difference amplifier differentially amplifies the output power setting value 56dBm, and outputs a differential voltage value of 1dBm, which is negative, and the PID circuit starts to accumulate the gain adjustment value (negative value). The adder output starts to decrease from 65dB, when the PID accumulated gain adjustment value reaches -1dB, the corrected gain control value output by the adder = 65-1=64dB, the output power = -8+64=56dBm, the difference amplifier outputs 0, and the PID circuit output stabilizes at -1dB gain adjustment value, and the power amplifier output stabilizes at 56dBm. If the input jumps to -10dBm at this time, due to the stability of the loop gain, the output power detection value is equal to -10+64=54dBm (251W), the difference amplifier differentially amplifies the output power setting value 56dBm, and outputs a differential voltage value of 2dBm, which is positive, and the PID circuit starts to accumulate the gain adjustment value (changes from -1dB to positive direction), the adder output starts to increase from 64dB, when the PID accumulated gain adjustment value reaches +1dB, the corrected gain control value output by the adder = 65+1=66dB, the output power = -10+66=56dBm, the difference amplifier outputs 0, and the PID circuit output stabilizes at +1dB gain adjustment value, and the power amplifier output stabilizes at 56dBm.

[0059] In this embodiment, when the constant gain mode is used, the gain is set to 65 dB, the maximum power setting value and the output power setting value are both 56.5 dBm (447 W), and the device operates in the constant gain mode when the input is ≤-8.5 dBm. For example, when the input is -10 dBm, the output = -10 + 65 = 55 dBm (316 W); when the input is -9 dBm, the output = -9 + 65 = 56 dBm (400 W). When the input instantaneously changes to -8 dBm, the output power = -8 + 65 = 57 dBm (500 W) due to the link gain of 65 dB, the maximum power comparator output = 56.5 - 57 is negative, triggering the single-chip microcomputer interrupt, the single-chip microcomputer switches the mode switching switch to the constant power mode, and enters the maximum power protection state. At this time, the differential amplifier output is 56.5 - 57 = -0.5 dBm, the PID cumulative gain adjustment value changes to -0.5 dB, when the cumulative value is -0.5 dB, the loop gain = 65 - 0.5 = 64.5 dB, the output changes to -8 + 64.5 = 56.5 dBm (447 W), the differential amplifier output is 0, the PID maintains the output = -0.5 dB, the loop gain is maintained at 64.5 dB, the gain comparator 65 - 64.5 = 0.5 is positive, and the circuit stabilizes the output of 56.5 dBm (447 W). When the input jumps to -7 dBm again, the power amplifier output is 64.5 - 7 = 57.5 dBm (562 W), at this time, the differential amplifier output is 56.5 - 57.5 = -1 dBm, the PID cumulative gain adjustment value changes to -1.5 dB, when the cumulative value is -1.5 dB, the loop gain = 65 - 1.5 = 63.5 dB, the output changes to -7 + 63.5 = 56.5 dBm (447 W), the differential amplifier output is 0, the PID maintains the output = -1.5 dB, the loop gain is maintained at 63.5 dB, the gain comparator 65 - 63.5 = 1.5 is positive, and the circuit stabilizes the output of 56.5 dBm (447 W). When the input jumps from -7 dBm to -10 dBm, the power amplifier output is 63.5 - 10 = 53.5 dBm (224 W), at this time, the differential amplifier output is 56.5 - 53.5 = +3 dBm, the PID cumulative gain adjustment value changes to +3 dB, when the cumulative value is > 0 dB, the adder output is > 65 dB, the gain comparator output is negative, triggering the single-chip microcomputer interrupt, the single-chip microcomputer switches the mode switching switch back to the constant gain mode, and exits the maximum power protection state. The link gain is 65 dB, and the power amplifier stabilizes the output of -10 + 65 = 55 dBm (316 W).

[0060] Obviously, the above embodiments of the present application are only examples for clearly illustrating the technical solutions of the present application, and are not intended to limit the specific embodiments of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the claims of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A power amplifier control circuit with switchable constant power or constant gain modes, characterized in that, It includes an amplification link and a regulation circuit. The amplification link includes a preamplifier, a signal attenuator, a driver amplifier, a final power amplifier, and a signal coupler, which are connected in sequence from the signal input terminal to the signal output terminal. The regulation circuit is used to send a gain adjustment signal to the signal attenuator and maintain the stability of the amplification link. The adjustment circuit includes a mode switching switch, a constant power adjustment circuit, and a constant gain adjustment circuit. The mode switching switch is used to switch the connection of the constant gain adjustment circuit or the constant power adjustment circuit. The constant gain adjustment circuit sets a fixed attenuation value through the signal attenuator, and the constant power adjustment circuit sets a corrected attenuation value through the signal attenuator. The constant gain adjustment circuit includes a fixed gain setting terminal, which is connected to the signal attenuator through the mode switching switch and inputs an attenuation setting value that matches the fixed gain setting value. The constant power adjustment circuit includes a detector amplification module, an automatic feedback module, and an adder module. The input terminal of the detector amplification module is connected to the signal coupler and outputs a power error value. The automatic feedback module is connected between the detector amplification module and the adder module and outputs the input power error value as a gain adjustment value. The output terminal of the adder module outputs a corrected gain control value, which is connected to the signal attenuator via a mode switching switch. The signal attenuator is used to receive a corrected attenuation value that matches the corrected gain control value. The addition module includes an adder and a fixed gain setting terminal. The adder is used to add the input gain adjustment value to the fixed gain setting value of the fixed gain setting terminal and output the corrected gain control value.

2. The control circuit according to claim 1, characterized in that, The detection and amplification module includes an output power detector, a differential amplifier, and an output power setting terminal. The input terminal of the output power detector receives the sampled output power of the signal coupler and outputs the detected power value to the differential amplifier. The input terminal of the differential amplifier is connected to both the output terminal of the output power detector and the output power setting terminal, and is used to amplify the difference between the detected power value and the output power setting value of the output power setting terminal, and output the power error value.

3. The control circuit according to claim 2, characterized in that, The automatic feedback module includes a PID circuit, the input of which is connected to the output of the differential amplifier, for adjusting the power error signal response curve and outputting a gain adjustment value; the input of the adder is connected to both the output of the PID circuit and the fixed gain setting terminal.

4. The control circuit according to claim 3, characterized in that, When the detected power value is greater than the output power setting value, the differential amplifier outputs a negative voltage. After processing by the PID circuit, a gain adjustment value is generated. This value is added to the fixed gain setting value to control the signal attenuator to reduce its gain. When the detected power value is less than the output power setting value, the differential amplifier outputs a positive voltage. After processing by the PID circuit, a gain adjustment value is generated. This value is added to the fixed gain setting value to control the signal attenuator to increase its gain. The PID circuit is used to adjust the power error signal response curve and maintain the stability of the gain adjustment value.

5. The control circuit according to any one of claims 2-4, characterized in that, The adjustment circuit further includes a polarity adjustment circuit, which is connected between the mode switching switch and the signal attenuator. The polarity adjustment circuit is used to adjust the positive and negative polarities of the output signal of the mode switching switch and match the polarity and control level range of the control voltage of the signal attenuator.

6. The control circuit according to claim 5, characterized in that, It also includes a protection circuit, which includes a maximum power protection module, a gain discrimination module, and a microcontroller. The maximum power protection module and the gain discrimination module are connected in parallel to the microcontroller. The microcontroller sends a switching signal to the mode switching switch according to the working state of the gain discrimination module and the maximum power protection module. The mode switching switch receives the signal and switches to the constant power adjustment circuit or the constant gain adjustment circuit.

7. The control circuit according to claim 6, characterized in that, The gain discrimination module includes a gain comparator, the input of which is connected to both the output of the adder and the fixed gain setting terminal. This comparator is used to determine the magnitude of the corrected gain control value and the fixed gain setting value, and outputs a signal to the microcontroller. The maximum power protection module includes a power comparator, the input of which is connected to both the output of the output power detector and the maximum power setting terminal. This comparator is used to determine the magnitude of the detected power value and the maximum power setting value, and outputs a signal to the microcontroller.

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