Output power control circuit, power amplifier and communication terminal

Abstract

The application provides an output power control circuit, a power amplifier and a communication terminal, relates to the technical field of radio frequency communication, and solves the problem that in the prior art, a high-power power amplifier SSPA is prone to abnormal risks during transient switching of a waveguide switch, thereby affecting system operation; the scheme is based on the working characteristics of a power tube and controls the gate voltage of the power tube through an output power control circuit, thereby realizing control over the output power of the power amplifier; moreover, through control over the gate voltage of the power tube, the circuit can be free from the influence of frequency bands and power, and does not need to be additionally designed for radio frequency matching, which helps to improve the application range of the circuit. Moreover, the response time of the output power control circuit is short, the power tube state can be quickly switched, and the output power of the power tube can be reduced during transient switching of the waveguide switch, thereby avoiding the abnormal risks of the waveguide switch.

Description

Technical Field

[0001] This application relates to the field of radio frequency communication technology, and in particular to an output power control circuit, a power amplifier, and a communication terminal. Background Technology

[0002] High-power solid-state power amplifiers (SSPAs) are used in radio frequency communication systems in C-band, Ku-band, and Ka-band. To ensure communication reliability, one or more SSPAs are typically redundantly configured in a 1:1 or 1:2 ratio. This allows for rapid switching to a backup SSPA via waveguide switches in case one SSPA malfunctions. Furthermore, the output power of SSPAs can reach 4000W in the C-band, 2000W in the Ku-band, and 500W in the Ka-band.

[0003] However, during waveguide switch switching, if the power amplifier SSPA output power exceeds 200W, the transient switching of the waveguide switch may lead to risks such as arcing and electric arcing due to high output power mismatch. The higher the output power, the greater the risk, and the accumulation of such risks over time can cause waveguide switch failure. Furthermore, the waveguide switch's switching time is approximately 40ms; extending this time would result in a power interruption time exceeding the required 50ms, thus affecting the communication system. Therefore, in related technologies, high-power power amplifier SSPAs are prone to abnormal risks during transient waveguide switch switching, which can affect system operation. Utility Model Content

[0004] This application provides an output power control circuit, a power amplifier, and a communication terminal, which solves the problem in related technologies that high-power power amplifiers (SSPAs) are prone to abnormal risks during transient switching of waveguide switches, thus affecting system operation. This solution can avoid abnormal risks of waveguide switches by reducing the output power of the power transistors during transient switching of waveguide switches.

[0005] In a first aspect, this application provides an output power control circuit for use in a power amplifier in a radio frequency redundancy system. The radio frequency redundancy system includes a waveguide switch and at least two power amplifiers. The output terminals of the power amplifiers are connected to the waveguide switch, and the power amplifiers include multiple cascaded power transistors to adjust the output power by controlling the gain of the power transistors. The output power control circuit includes an MCU module, a channel switch module, a gate voltage module, a voltage follower module, and a bias module.

[0006] The first output terminal of the MCU module is used to output a positive voltage, and the second output terminal of the MCU module is used to output a switching control signal. The MCU module is used to output different state switching control signals according to the switching state of the waveguide switch. The input terminal of the channel switch module is connected to the first output terminal of the MCU module, and the control terminal of the channel switch module is connected to the second output terminal of the MCU module. The channel switch module includes a first output terminal and a second output terminal. The first output terminal of the channel switch module is grounded. The channel switch module is used to connect the input terminal of the channel switch module to the first output terminal or the second output terminal of the channel switch module according to the switching control signal. The first potential access terminal of the gate voltage module is connected to a negative voltage, and the second potential access terminal of the gate voltage module is grounded. The gate voltage module includes a first access terminal and a second access terminal. The first access terminal of the gate voltage module is connected to the second output terminal of the channel switch module. The gate voltage module is used to form a loop that is grounded or connected to a positive voltage when the channel switch module is connected to different output terminals, and provides different gate voltages through the second access terminal to control the power transistor to work or be cut off. The input terminal of the voltage follower module is connected to the second access terminal of the gate voltage module. The voltage follower module is used to output the gate voltage of the power transistor and isolate the interference of other signals on the gate voltage. The input of the bias module is connected to the output of the voltage follower module, and the output of the bias module is connected to the gate of the power transistor of the power amplifier. The bias module is used to provide the gate voltage for the power transistor and prevent radio frequency signal crosstalk.

[0007] Secondly, this application also provides a power amplifier that includes the output power control circuit provided in the first aspect above. The power amplifier is used to connect to a waveguide switch in an RF redundancy system to reduce the output power through the output power control circuit when the waveguide switch switches to a different state.

[0008] Thirdly, this application also provides a communication terminal, which includes a waveguide switch and at least two power amplifiers as provided in the second aspect above.

[0009] This application's solution leverages the operating characteristics of the power transistor and controls its gate voltage via an output power control circuit to regulate the power amplifier's output power. Furthermore, by controlling the power transistor's gate voltage, the circuit becomes unaffected by frequency band or power limitations, eliminating the need for additional RF matching design and thus expanding its application range. Additionally, the output power control circuit in this solution has a short response time, enabling rapid switching of the power transistor's state. This allows for reducing the power transistor's output power during transient waveguide switch switching, thereby preventing potential risks of waveguide switch malfunctions. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure of a radio frequency redundancy system provided in an embodiment of this application.

[0011] Figure 2This is a schematic block diagram of an output power control circuit provided in an embodiment of this application.

[0012] Figure 3 This is a schematic diagram of the output power control circuit provided in an embodiment of this application. Detailed Implementation

[0013] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present application and are not intended to limit the scope of the present application. Furthermore, it should be noted that, for ease of description, the accompanying drawings only show the parts relevant to the embodiments of the present application, and not all structures. Those skilled in the art, after reading this specification, should be able to deduce that any combination of technical features can constitute an optional implementation method, provided that the technical features do not contradict each other.

[0014] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship. In the description of this application, "multiple" means two or more, and "several" means one or more.

[0015] In recent years, satellite communication technology has developed rapidly. Satellite communication systems have been widely used due to their high transmission power, precise point-to-point communication, continuously improving transmission capacity, strong anti-interference capabilities, and good network mobility. In particular, the application of high-power solid-state power amplifiers (SSPAs) in main stations is increasing. Relying on the continuous development and maturation of transistor technologies such as GaAs (gallium arsenide) and GaN (gallium nitride) and multi-channel combining technologies, the development of high-power solid-state power amplifiers (SSPAs) has progressed by leaps and bounds. Their main application frequency bands involve the C-band, Ku-band, and Ka-band. Furthermore, their output power is constantly improving; currently, the industry standard for C-band amplifiers reaches 4000W, Ku-band reaches 2000W, and Ka-band reaches 500W.

[0016] However, in radio frequency communication systems, to ensure communication reliability, one or more power amplifier SSPAs are typically redundantly installed in the communication terminal using a 1:1 or 1:2 ratio, and connected to waveguide switches. However, during waveguide switch switching, if the power amplifier SSPA output power > 200W, the transient switching of the waveguide switch may lead to risks such as arcing and sparking due to high output power mismatch. The higher the output power, the greater the risk, and the accumulation of such risks over time can cause waveguide switch failure. Furthermore, the waveguide switch's switching time is approximately 40ms; extending the switching time would result in a power interruption time exceeding the required 50ms, thus affecting the communication system. Therefore, in related technologies, high-power power amplifier SSPAs are prone to abnormal risks during transient waveguide switch switching, affecting system operation.

[0017] To address this issue, this application provides an output power control circuit for use in a power amplifier within an RF redundancy system. The power amplifier includes multiple cascaded power transistors. Furthermore, the RF redundancy system includes a waveguide switch and at least two power amplifiers, with the output terminals of the power amplifiers connected to the waveguide switch. This output power control circuit adjusts the output power by controlling the gain of the power transistors, thereby reducing the output power of the power transistors during waveguide switch switching to prevent potential malfunctions or risks associated with the waveguide switch.

[0018] Figure 1 The figure shows a schematic diagram of a radio frequency redundancy system provided in one embodiment of this application. In one embodiment, the radio frequency redundancy system includes a waveguide switch 112 and two power amplifiers (SSPA-A and SSPA-B in the figure). The output terminals of all power amplifiers are connected to the waveguide switch 112, and the input terminals of all power amplifiers are connected to a power divider 111. The waveguide switch 112 has four ports, as shown in the figure: port 1, port 2, port 3, and port 4. Port 2 is connected to an antenna or the next stage circuit, port 4 is connected to a load 113, and ports 1 and 2 are connected to different power amplifiers. The waveguide switch 112 has two operating states: a first state where ports 1 and 2 are on and ports 3 and 4 are on, and a second state where ports 1 and 4 are on and ports 3 and 2 are on, as shown in the figure. Figure 1 The diagram illustrates the connection structure between the two power amplifiers and waveguide switch 112 when waveguide switch 112 is in its first state. It can be understood that after the signal is transmitted to the two power amplifiers via power divider 111, the amplified signal is transmitted to the antenna or load 113 via waveguide switch 112. The transmission of the signal from one power amplifier to the antenna and the signal from the other power amplifier to the load 113 is achieved by controlling the state switching of waveguide switch 112. It is conceivable that, in practical applications, this RF redundancy system could be integrated into communication terminals.

[0019] The output power control circuit provided in this application can control the output power of the power amplifier during waveguide switching. The circuit controls the output power by controlling the gain of the power transistor in the power amplifier, thereby reducing the output power of the power amplifier when the waveguide switch is switched. Figure 2 This is a block diagram illustrating the principle of an output power control circuit according to an embodiment of this application. The dashed box in the diagram represents the RF link of the power amplifier, and the state of the power transistors in this RF link is controlled by the output power control circuit. As shown, the output power control circuit includes an MCU module 210, a channel switch module 220, a gate voltage module 230, a voltage follower module 240, and a bias module 250. The input terminal of the channel switch module 220 is connected to the first output terminal of the MCU module 210, and the control terminal of the channel switch module 220 is connected to the second output terminal of the MCU module 210. The channel switch module 220 includes a first output terminal and a second output terminal, and the first output terminal of the channel switch module 220 is grounded. The first potential access terminal of the gate voltage module 230 is connected to a negative voltage, and the second potential access terminal of the gate voltage module 230 is grounded. The gate voltage module 230 includes a first access terminal and a second access terminal. The first access terminal of the gate voltage module 230 is connected to the second output terminal of the channel switch module 220, and the input terminal of the voltage follower module 240 is connected to the second access terminal of the gate voltage module 230. The input terminal of the bias module 250 is connected to the output terminal of the voltage follower module 240, and the output terminal of the bias module 250 is connected to the gate terminal of the power transistor of the power amplifier.

[0020] The MCU module 210 provides a positive voltage and output switching control signals. For example, the first output of the MCU module 210 outputs a positive voltage, and the second output outputs a switching control signal. It is conceivable that the MCU module 210 can output different switching control signals based on the switching state of the waveguide switch, switching the waveguide switch to the corresponding state and enabling different ports to conduct. The channel switch module 220 connects its input to either its first or second output based on the switching control signal. In other words, by receiving the switching control signal, the channel switch module 220 responds by turning on either its first or second output, thus forming different conduction channels.

[0021] The gate voltage module 230 is used to form a grounded or positive voltage loop when the channel switch module 220 is connected to different output terminals, and provides different gate voltages through the second access terminal to control the power transistor to operate or be turned off. That is, when the channel switch module 220 is connected to different output terminals, such as when the channel switch module 220 is connected to the input terminal and the first output terminal, the gate voltage module 230 forms a grounded loop, thereby providing a first gate voltage through the second access terminal of the gate voltage module 230 to control the power transistor to be turned off; while when the channel switch module 220 is connected to the input terminal and the second output terminal, the gate voltage module 230 forms a positive voltage loop, that is, it provides a positive voltage to the MCU module 210 through the channel switch module 220, and provides a second gate voltage through the second access terminal of the gate voltage module 230 to control the power transistor to be turned on.

[0022] The voltage follower module 240 is used to output the gate voltage of the power transistor and isolate the interference of other signals on the gate voltage. Then, the gate voltage provided by the gate voltage module 230 is transmitted to the bias module 250 through the voltage follower module 240. The bias module 250 is used to provide the gate voltage for the power transistor and prevent radio frequency signal crosstalk.

[0023] Understandably, the MCU module 210 selects the corresponding conduction channel by controlling the channel switch module 220 to adapt to the state of the waveguide switch. Then, during the waveguide switch switching process, the gate voltage module 230 provides the first gate voltage to the power transistor to cut off the power transistor and reduce the output power in the RF link of the power amplifier.

[0024] Therefore, this solution, based on the operating characteristics of the power transistor and controlling its gate voltage via an output power control circuit, achieves control over the output power of the power amplifier. Furthermore, by controlling the gate voltage of the power transistor, the circuit becomes unaffected by frequency band or power, and eliminates the need for additional RF matching design, thus expanding its application range. Moreover, the output power control circuit in this solution has a short response time, enabling rapid switching of the power transistor's state. This allows for reduction of the power transistor's output power during transient waveguide switch switching, thereby avoiding the risk of waveguide switch malfunctions.

[0025] In one embodiment, the channel switch module includes an analog switch chip, a first resistor, a second resistor, a third resistor, and a first capacitor. Optionally, the analog switch chip is a single-pole double-throw (SPDT) switch chip, which uses a one-input, two-output connection to form two different output channels, thereby connecting the positive voltage output by the MCU module to the input pin and outputting it through one of the output pins. Specifically, the power supply pin of the analog switch chip is connected to a first operating voltage, and the power supply pin of the analog switch chip is also connected to the grounded first capacitor, and the ground pin of the analog switch chip is grounded. Furthermore, the enable pin of the analog switch chip is connected to the first end of the first resistor, the second end of the first resistor is connected to the second output terminal of the MCU module to receive a switching control signal, the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the first capacitor.

[0026] The first data pin of the analog switch chip is used to connect to the positive voltage output by the MCU module. The second data pin of the analog switch chip is connected to the first end of the third resistor, and the second end of the third resistor is grounded. The third data pin of the analog switch chip is connected to the first access terminal of the gate voltage module. The analog switch chip is used to connect the first data pin with the second data pin or the third data pin according to the switching control signal.

[0027] It is understandable that a positive voltage is applied to the first data pin of the analog switch chip, and the second and third data pins of the analog switch chip serve as the two output terminals of the analog switch chip. When the enable pin of the analog switch chip receives the corresponding switching control signal, the analog switch chip will connect the first data pin and the second data pin or the first data pin and the third data pin to form a conduction channel, thereby transferring the positive voltage to the third resistor or to the gate voltage module.

[0028] As can be conceived, when one of the two output terminals of the analog switch chip is on, the other output terminal is floating. Therefore, when the third data pin of the analog switch chip is floating, the gate voltage module forms a ground loop, thereby providing a first gate voltage through the second access terminal of the gate voltage module to control the power transistor to turn off; when the third data pin of the analog switch chip is on, the gate voltage module is connected to a positive voltage, thus forming a loop connected to a positive voltage, thereby providing a second gate voltage through the second access terminal of the gate voltage module to control the power transistor to turn on. Therefore, this solution can use an analog switch to achieve switching between different conduction channels, isolating adjacent circuit modules while also achieving high-speed switching, thus contributing to efficient control of the power transistor state.

[0029] In one embodiment, the gate voltage module includes a fourth resistor, a fifth resistor, and a first diode. Specifically, a negative voltage is applied to the first terminal of the fourth resistor, the second terminal of the fourth resistor is connected to the first terminal of the fifth resistor, the second terminal of the fifth resistor is connected to the cathode of the first diode, and the anode of the first diode is grounded. The second terminal of the fifth resistor serves as the first access terminal of the gate voltage module, and the first terminal of the fifth resistor serves as the second access terminal of the gate voltage module.

[0030] Understandably, in response to the change in the conduction path of the channel switch module, the state of the first input terminal of the gate voltage module is different. For example, when the first output terminal of the channel switch module outputs a positive voltage, the second output terminal of the channel switch module is floating. In this case, the fifth resistor is directly connected to the first diode, and the first diode is in the conducting state. At this time, a grounding loop is formed in the gate voltage module through the fourth resistor, the fifth resistor, and the first diode, so that the fifth resistor, the fourth resistor, and the first diode can perform voltage division, thereby providing the first gate voltage to the voltage follower module.

[0031] When the first output terminal of the channel switch module is floating, the second output terminal of the channel switch module outputs a positive voltage. The fifth resistor is connected to the positive voltage, which turns off the first diode. In response, the gate voltage module forms a loop with the positive voltage through the fourth resistor, the fifth resistor and the connected positive voltage, so that the fifth resistor and the fourth resistor divide the voltage, thereby providing the second gate voltage to the voltage follower module.

[0032] In response, this solution, through the setting of the gate voltage module, can form different loops when the access terminal is floating or conducting using the same structure, thereby providing different gate voltages for the subsequent circuits. This effectively matches the gate voltage requirements of the power transistor when the waveguide switch is switching, and the circuit structure is simple, which helps to miniaturize the circuit design.

[0033] In one embodiment, the voltage follower module includes an operational amplifier, a sixth resistor, a second capacitor, and a third capacitor. The non-inverting input of the operational amplifier is connected to the second input terminal of the gate voltage module, the inverting input is connected to the output, the output is connected to the first terminal of the sixth resistor, the second terminal of the sixth resistor serves as the output of the voltage follower module, and is also connected to the grounded second capacitor. The positive power supply pin of the operational amplifier is grounded, and the negative power supply pin is connected to a negative voltage, also connected to the grounded third capacitor. The third capacitor is used to stabilize the voltage input to the negative power supply pin. The operational amplifier, the second capacitor, and the sixth resistor form a voltage follower structure, allowing the output voltage to follow changes in the input voltage. This provides transmission isolation for the voltage generated at the front end, thereby providing sufficient source and sink currents to drive the power transistor when it needs to operate. Furthermore, the second capacitor and the sixth resistor stabilize the output of the operational amplifier. Therefore, this scheme forms a voltage follower structure based on an operational amplifier, thereby providing sufficient source and sink currents to drive the power transistor, and also providing isolation, thus effectively controlling the power transistor to efficiently regulate the output power of the power amplifier.

[0034] Furthermore, the placement of the sixth resistor ensures that the voltage follower module will not experience self-oscillation. Moreover, by configuring the selection of the sixth resistor and the second capacitor, the RC time constant of the circuit can be reduced, thereby improving the control response speed of the power amplifier's output power. Optionally, the resistance of the sixth resistor is less than or equal to 5.1Ω, and the capacitance of the second capacitor is less than or equal to 1μF, corresponding to an RC time constant of less than or equal to 5.1μs for both the sixth resistor and the second capacitor. This solution strictly controls the circuit time constant through hardware circuitry, resulting in a shorter circuit response time. Compared to the switching time of the waveguide switch itself (approximately 40ms), this solution does not significantly increase the system switching time, thus ensuring stable system operation.

[0035] In one embodiment, the bias module includes a microstrip line unit, a fourth capacitor, and a fifth capacitor. One end of the microstrip line unit is connected to the gate of the power transistor, and the other end of the microstrip line unit is connected to the first terminal of the fourth capacitor. The first terminal of the fourth capacitor is also connected to the output terminal of the voltage follower module, and the second terminal of the fourth capacitor is grounded. The fifth capacitor is connected in parallel with the fourth capacitor. It is understood that the parallel fourth and fifth capacitors stabilize the output voltage of the voltage follower module, and the microstrip line unit prevents radio frequency (RF) signals from interfering with circuits using DC signals, thus preventing the transmitted RF signals from affecting the output power control circuit. Therefore, this solution achieves signal isolation through the configuration of the bias module, preventing RF signals from interfering with the output power control circuit, which helps maintain stable circuit operation and improves circuit reliability.

[0036] Optionally, the microstrip line unit includes a quarter-wavelength sector microstrip line to avoid signal crosstalk. The length of the sector microstrip line is determined according to the wavelength of the radio frequency signal corresponding to the applied frequency band.

[0037] Figure 3 The figure shows a schematic diagram of the output power control circuit provided in an embodiment of this application. In the power amplifier, two power transistors are cascaded. In one of the power transistors, the gate voltage of the power transistor is adjusted by the output power control circuit of this solution to adjust the gain of the power transistor. For example, the power transistor can be turned on to perform gain amplification, or the power transistor can be turned off to not provide gain amplification function.

[0038] In the channel switch module 220, the power supply pin of the analog switch chip U1 is connected to a first operating voltage (e.g., 3.3V), and the power supply pin of the analog switch chip U1 is also connected to a grounded first capacitor C1 to stabilize the voltage connected to the power supply pin of the analog switch chip U1. Furthermore, the ground pin of the analog switch chip U1 is grounded. The enable pin of the analog switch chip U1 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 is connected to the second output terminal of the MCU module (not shown in the figure) to receive the switching control signal (Vctrl_D1). The first end of the second resistor R2 is connected to the second end of the first resistor R1, and the second end of the second resistor R2 is connected to the first capacitor C1. The switching control signal is then connected to the enable pin of the analog switch chip U1 through the first resistor R1 to control the analog switch chip U1 to provide the corresponding conduction channel. Additionally, the first data pin of the analog switch chip U1 is used to receive the positive voltage output by the MCU module (VG in the figure), the second data pin of the analog switch chip U1 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is grounded, and the third data pin of the analog switch chip U1 is connected to the second end of the fifth resistor R5. It is conceivable that by providing switching control signals for different level states, the analog switch chip U1 can connect a positive voltage to the third resistor R3 or the fifth resistor R5.

[0039] In the gate voltage module 230, the first terminal of the fourth resistor R4 is connected to a negative voltage, the second terminal of the fourth resistor R4 is connected to the first terminal of the fifth resistor R5, the second terminal of the fifth resistor R5 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is grounded. Therefore, when the analog switch chip U1 connects a positive voltage to the third resistor R3 (i.e., the third data pin of the analog switch U1 is left floating), the first diode D1 conducts, and the fourth resistor R4, the fifth resistor R5, and the first diode D1 form a negative voltage to ground loop. Through voltage division by the resistors, the first terminal of the fifth resistor R5 can provide the first gate voltage. Conversely, when the analog switch chip U1 connects a positive voltage to the fifth resistor R5, the first diode D2 is cut off, and the fourth resistor R4 and the fifth resistor R5 form a positive voltage to negative voltage loop. Through voltage division by the resistors, the first terminal of the fifth resistor R5 can provide the second gate voltage. The first gate voltage and the second gate voltage are different and are used to control the power transistor to different states.

[0040] Furthermore, in the voltage follower module 240, the non-inverting input of operational amplifier U2A is connected to the first terminal of the fifth resistor R5, the inverting input of operational amplifier U2A is connected to the output of operational amplifier U2A, the output of operational amplifier U2A is connected to the first terminal of the sixth resistor R6, the second terminal of the sixth resistor R6 serves as the output of the voltage follower module 240, and the second terminal of the sixth resistor R6 is also connected to the grounded second capacitor C2. The positive power supply pin of operational amplifier U2A is grounded, the negative power supply pin of operational amplifier U2A is connected to a negative voltage (e.g., -5V), and the negative power supply pin of operational amplifier U2A is also connected to the grounded third capacitor C3. In the bias module 250, one end of the microstrip line unit RS1 is connected to the gate of the power transistor, the other end of the microstrip line unit RS1 is connected to the first terminal of the fourth capacitor C4, and the first terminal of the fourth capacitor C4 is also connected to the second terminal of the sixth resistor R6. The second terminal of the fourth capacitor C4 is grounded, and the fifth capacitor C5 is connected in parallel with the fourth capacitor C4.

[0041] Understandably, when the power transistor needs to be turned on, the MCU module outputs a high-level switching control signal, causing the analog switch chip U1 to connect a positive voltage to the fifth resistor R5, thereby turning off the first diode D1. The voltage division between the fifth resistor R5 and the fourth resistor R4 ensures that the provided gate voltage meets the turn-on condition of the power transistor. This gate voltage is then transmitted to the bias unit via the voltage follower structure formed by the operational amplifier U2A, and further transmitted to the gate of the power transistor via the microstrip line unit. Conversely, when the power transistor needs to be turned off, the MCU module outputs a low-level switching control signal, causing the analog switch chip U1 to connect a positive voltage to the third resistor R3, while the third data pin of the analog switch chip U1 is left floating. In this case, the first diode D1 is turned on, forming a ground loop. The voltage division between the fifth resistor R5, the fourth resistor R4, and the first diode D1 ensures that the provided gate voltage is insufficient to turn on the power transistor. It is conceivable that the change in the switching control signal can respond to the switching of the waveguide switch, so as to control the power transistor to be cut off when the waveguide switch is switching, and to control the power transistor to be turned on after the waveguide switch has completed switching, thereby realizing the control of the output power of the power amplifier.

[0042] Therefore, it is evident that this solution features a simple circuit structure that directly acts on the gate of the power transistor, rather than the RF section. This makes it unaffected by frequency band or power, eliminating the need for additional RF matching design, thus expanding the circuit's application range and facilitating miniaturization. Furthermore, the hardware circuit design allows for strict control of the circuit's time constant, resulting in a short response time and power interruption time that meets application requirements.

[0043] This application also provides a power amplifier including the output power control circuit provided in the above embodiments, enabling the power amplifier to be connected to a waveguide switch in an RF redundancy system, thereby reducing the output power through the output power control circuit when the waveguide switch switches to a different state. This power amplifier can adjust the output power in the RF link through the output power control circuit to avoid high output power mismatch during waveguide switch switching, thus effectively protecting the device.

[0044] Optionally, in the case of a power amplifier with multiple power transistors, the output power control circuit of this scheme can be applied to the gate of at least one power transistor to achieve control of the output power.

[0045] This application also provides a communication terminal, which includes a waveguide switch and a power amplifier provided in the above embodiments. It is conceivable that the power amplifier includes the output power control circuit provided in the above embodiments, and the output terminal of the power amplifier is connected to the waveguide switch, so that the signal output by the corresponding power amplifier can be transmitted through the antenna by switching the waveguide switch. During the switching process of the waveguide switch, the communication terminal can output the control circuit to control the state of the power tube of the power amplifier to realize the control of the output power of the power amplifier, which helps to ensure the stability of communication.

[0046] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0047] Note that the above description is merely a preferred embodiment and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this application, and the scope of this application is determined by the scope of the appended claims.

Claims

1. An output power control circuit, characterized in that, A power amplifier is used in a radio frequency (RF) redundancy system, the RF redundancy system including a waveguide switch and at least two power amplifiers, the output terminals of the power amplifiers being connected to the waveguide switch, and the power amplifiers including multiple cascaded power transistors to adjust the output power by controlling the gain of the power transistors, the output power control circuit including: The MCU module has a first output terminal for outputting a positive voltage and a second output terminal for outputting a switching control signal. The MCU module is used to output switching control signals of different states according to the switching state of the waveguide switch. A channel switch module, wherein the input terminal of the channel switch module is connected to the first output terminal of the MCU module, and the control terminal of the channel switch module is connected to the second output terminal of the MCU module, the channel switch module includes a first output terminal and a second output terminal, the first output terminal of the channel switch module is grounded, and the channel switch module is used to connect the input terminal of the channel switch module with the first output terminal or the second output terminal of the channel switch module according to the switching control signal; A gate voltage module is provided, wherein a first potential access terminal of the gate voltage module is connected to a negative voltage, and a second potential access terminal of the gate voltage module is grounded. The gate voltage module includes a first access terminal and a second access terminal. The first access terminal of the gate voltage module is connected to the second output terminal of the channel switch module. The gate voltage module is used to form a loop that is grounded or connected to a positive voltage when the channel switch module is connected to different output terminals, and to provide different gate voltages through the second access terminal to control the power transistor to work or be cut off. A voltage follower module, wherein the input terminal of the voltage follower module is connected to the second access terminal of the gate voltage module, and the voltage follower module is used to output control of the gate voltage of the power transistor and isolate interference from other signals to the gate voltage; A bias module is provided, the input of which is connected to the output of the voltage follower module, and the output of which is connected to the gate of the power transistor of the power amplifier. The bias module is used to provide the gate voltage to the power transistor and prevent radio frequency signal crosstalk.

2. The output power control circuit according to claim 1, characterized in that, The channel switch module includes an analog switch chip, a first resistor, a second resistor, a third resistor, and a first capacitor; The power supply pin of the analog switch chip is connected to a first operating voltage, and the power supply pin of the analog switch chip is also connected to a grounded first capacitor, and the grounding pin of the analog switch chip is grounded. The enable pin of the analog switch chip is connected to the first end of the first resistor, the second end of the first resistor is connected to the second output terminal of the MCU module to receive the switching control signal, the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the first capacitor. The first data pin of the analog switch chip is used to connect to the positive voltage output by the MCU module. The second data pin of the analog switch chip is connected to the first end of the third resistor, the second end of the third resistor is grounded, and the third data pin of the analog switch chip is connected to the first access terminal of the gate voltage module. The analog switch chip is used to connect the first data pin to the second data pin or the third data pin according to the switching control signal.

3. The output power control circuit according to claim 2, characterized in that, The analog switch chip is a single-pole double-throw switch chip, and the single-pole double-throw switch chip adopts a one-input two-output connection method to connect the positive voltage output by the MCU module to the input pin of the single-pole double-throw switch chip, and output it through one of the output pins.

4. The output power control circuit according to claim 1, characterized in that, The gate voltage module includes a fourth resistor, a fifth resistor, and a first diode; The first end of the fourth resistor is connected to a negative voltage, the second end of the fourth resistor is connected to the first end of the fifth resistor, the second end of the fifth resistor is connected to the cathode of the first diode, and the anode of the first diode is grounded. Wherein, the second end of the fifth resistor serves as the first access terminal of the gate voltage module, and the first end of the fifth resistor serves as the second access terminal of the gate voltage module.

5. The output power control circuit according to claim 1, characterized in that, The voltage follower module includes an operational amplifier, a sixth resistor, a second capacitor, and a third capacitor; The non-inverting input of the operational amplifier is connected to the second input terminal of the gate voltage module, the inverting input of the operational amplifier is connected to the output terminal of the operational amplifier, the output terminal of the operational amplifier is connected to the first terminal of the sixth resistor, the second terminal of the sixth resistor serves as the output terminal of the voltage follower module, and the second terminal of the sixth resistor is also connected to a grounded second capacitor, the positive power supply pin of the operational amplifier is grounded, the negative power supply pin of the operational amplifier is connected to a negative voltage, and the negative power supply pin of the operational amplifier is also connected to a grounded third capacitor.

6. The output power control circuit according to claim 5, characterized in that, The resistance of the sixth resistor is less than or equal to 5.1Ω, the capacitance of the second capacitor is less than or equal to 1μF, and the RC time constant of the sixth resistor and the second capacitor is less than or equal to 5.1μs.

7. The output power control circuit according to any one of claims 1-6, characterized in that, The bias module includes a microstrip line unit, a fourth capacitor, and a fifth capacitor. One end of the microstrip line unit is connected to the gate terminal of the power transistor, and the other end of the microstrip line unit is connected to the first terminal of the fourth capacitor. The first terminal of the fourth capacitor is also connected to the output terminal of the voltage follower module. The second terminal of the fourth capacitor is grounded, and the fifth capacitor is connected in parallel with the fourth capacitor.

8. The output power control circuit according to claim 7, characterized in that, The microstrip line unit comprises a quarter-wavelength fan-shaped microstrip line.

9. A power amplifier, characterized in that, The power amplifier includes an output power control circuit as described in any one of claims 1-8, wherein the power amplifier is configured to be connected to a waveguide switch in a radio frequency redundancy system to reduce the output power by the output power control circuit when the waveguide switch is in a switching state.

10. A communication terminal, characterized in that, It includes a waveguide switch and at least two power amplifiers as described in claim 9.

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