Direct-current broadband composite amplification device and signal amplification method

Abstract

The invention belongs to the technical field of signal generators, and particularly relates to a direct-current broadband composite amplification device and a signal amplification method, and the method comprises the steps that a signal shunt circuit receives an input signal and separates the input signal into a high-frequency path signal and a low-frequency path signal; the high-frequency amplification circuit amplifies a high-frequency path signal through a radio-frequency power amplifier, so that the high-bandwidth requirement is ensured; the low-frequency amplification circuit amplifies the low-frequency path signal to generate a low-frequency reference signal; a current sampling circuit of the feedback control circuit collects output current of the radio frequency power amplifier and converts the output current into a voltage feedback signal, and an integral amplification circuit adjusts current flowing into a common end of the radio frequency power amplifier according to the voltage feedback signal and a low-frequency reference signal, so that stable combined output of high-frequency and low-frequency signals is realized. According to the device, through shunt independent processing and closed-loop feedback adjustment, high-bandwidth and large-amplitude voltage swing and accurate direct current control are considered, and the device is adaptive to a high-frequency and high-power test scene of the signal generator.

Description

Technical Field

[0001] This application relates to the field of signal generator technology, and in particular to a DC broadband composite amplifier and signal amplification method. Background Technology

[0002] Signal generators are indispensable general-purpose test instruments in the field of electronic engineering. Currently, most signal generators on the market generally use integrated high-speed current-mode operational amplifiers as the core driving devices for their analog output channels.

[0003] However, limited by inherent device parameters such as the gain-bandwidth product and slew rate of integrated high-speed operational amplifiers, existing amplifier circuit structures struggle to output large-amplitude signals while maintaining high-frequency broadband characteristics. In other words, existing amplifier circuits cannot output wide-bandwidth DC signals, limiting the application range of signal generators in high-frequency, high-power testing scenarios.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art.

[0005] Application content In view of at least one of the above-mentioned technical problems, this application provides a DC broadband composite amplifier device and a signal amplification method. This solves the problem that existing amplifier circuits cannot output DC broadband signals, thus limiting the application range of signal generators in high-frequency, high-power testing scenarios.

[0006] In a first aspect, a DC broadband composite amplifier is provided, comprising: A signal splitter circuit is used to receive input signals and split the input signals into high-frequency path signals and low-frequency path signals; A high-frequency amplifier circuit includes an RF power amplifier, which has a control terminal, an output terminal, and a common terminal. The control terminal of the RF power amplifier is used to receive high-frequency path signals, and the output terminal of the RF power amplifier is connected to the circuit output terminal. Low-frequency amplifier circuit, used to amplify low-frequency path signals and generate low-frequency reference signals; The feedback control circuit includes a current sampling circuit and an integral amplifier circuit. The current sampling circuit is connected to the output terminal of the RF power amplifier and is used to collect the output current of the RF power amplifier and convert it into a voltage feedback signal. The integral amplifier circuit is connected to the common terminal of the RF power amplifier and is used to adjust the current flowing into the common terminal of the RF power amplifier according to the voltage feedback signal and the low-frequency reference signal, thereby realizing the combined output of high-frequency and low-frequency signals.

[0007] This device uses a signal splitting circuit to divide the input signal into a high-frequency path signal and a low-frequency path signal. The high-frequency path signal is directly processed by the high-frequency amplifier circuit to ensure high bandwidth requirements. At the same time, the low-frequency path signal is processed by the low-frequency amplifier circuit and the feedback control circuit to achieve large voltage swing and precise DC control.

[0008] In some possible implementations, the high-frequency amplifier circuit also includes a high-frequency preamplifier, which is used to amplify the high-frequency path signal and output the amplified signal to the control terminal of the RF power amplifier.

[0009] In some possible implementations, the RF power amplifier is a transistor or a MOSFET.

[0010] In some possible implementations, the current sampling circuit includes a sampling resistor and a converter. The sampling resistor is connected to the output of the RF power amplifier, and the two inputs of the converter are connected to the two ends of the sampling resistor, respectively. The converter is used to acquire the current flowing through the sampling resistor and generate a voltage feedback signal.

[0011] In some possible implementations, the integrating amplifier circuit includes an error integrator and a control amplifier. The error integrator performs integration based on the voltage feedback signal and the low-frequency reference signal to generate a control voltage signal. The control amplifier responds to the control voltage signal and thereby regulates the current flowing into the common terminal of the RF power amplifier.

[0012] In some possible implementations, the control amplifier is a transistor, with its collector connected to a -5V voltage source, its base connected to an error integrator, and its emitter connected to the common terminal of the RF power amplifier.

[0013] In some possible implementations, when the voltage feedback signal is less than the low-frequency reference signal, the error integrator outputs a control voltage signal, which raises the base voltage of the control amplifier, increases the conduction degree of the control amplifier, increases the current flowing into the common terminal of the RF power amplifier, and causes the output current of the RF power amplifier to increase until the voltage feedback signal is equal to the low-frequency reference signal.

[0014] In some possible implementations, the low-frequency amplifier circuit includes a low-frequency gainer, which is used to amplify the low-frequency path signal.

[0015] In some possible implementations, the device also includes a zeroing circuit, which includes an adjustable voltage source and an adjusting resistor. One end of the adjusting resistor is connected to the adjustable voltage source, and the other end of the adjusting resistor is connected to an integrating amplifier circuit for adjusting the DC bias voltage at the circuit output.

[0016] Secondly, a signal amplification method implemented by a DC broadband composite amplifier is provided, comprising: It receives input signals and divides them into high-frequency and low-frequency path signals. The high-frequency path signal is transmitted to the high-frequency amplification module for amplification, and then the signal is output to the circuit output terminal through the radio frequency power amplification device. The low-frequency path signal is transmitted to the low-frequency amplification module for amplification to obtain the low-frequency reference signal; The output current of the high-frequency amplifier module at the circuit output terminal is collected, and the collected output current is converted into a feedback voltage signal; The low-frequency reference signal is compared with the feedback voltage signal and integrated to generate the control voltage signal; By adjusting the operating current of the high-frequency amplifier module using a control voltage signal, the DC operating point of the high-frequency amplifier module is stabilized, and the low-frequency path signal is superimposed on the circuit output terminal to achieve DC broadband large signal output.

[0017] The present application will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Circuit diagram of the DC broadband composite amplifier provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the DC broadband composite amplifier provided in the embodiments of this application; Figure 3 for Figure 2 A schematic diagram of the first structure of a medium-to-high frequency amplifier circuit; Figure 4 for Figure 2 A schematic diagram of the second structure of a medium-to-high frequency amplifier circuit; Figure 5 for Figure 2 A schematic diagram of the feedback control circuit. In the diagram: 100, signal branch circuit; 200. High-frequency amplifier circuit; 210. Radio frequency power amplifier; 220. High-frequency preamplifier; 300. Low-frequency amplifier circuit; 310. Low-frequency gainer; 400. Feedback control circuit; 410. Current sampling circuit; 420. Integrating amplifier circuit; 411. Sampling resistor; 412. Converter; 421. Error integrator; 422. Control amplifier; 500, Zeroing circuit; OUTPUT, circuit output terminal; Detailed Implementation

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0021] In related technologies, due to limitations imposed by the inherent device parameters of integrated high-speed operational amplifiers, such as the gain-bandwidth product and slew rate, existing amplifier circuit structures struggle to output large-amplitude signals while maintaining high-frequency broadband characteristics. In other words, existing amplifier circuits cannot output wide-bandwidth DC signals, limiting the application range of signal generators in high-frequency, high-power testing scenarios. To address these issues, this DC broadband composite amplifier device uses a signal splitter circuit 100 to divide the input signal into a high-frequency path signal and a low-frequency path signal. The high-frequency path signal is directly processed by the high-frequency amplifier circuit, ensuring high bandwidth requirements. Simultaneously, the low-frequency path signal passes through a low-frequency amplifier circuit and a feedback control circuit, achieving large-amplitude voltage swings and precise DC control.

[0022] The following is a detailed description of the DC broadband composite amplifier.

[0023] Figure 1 This is a circuit diagram of the DC broadband composite amplifier provided in the embodiments of this application. Figure 2 This is a schematic diagram of the DC broadband composite amplifier device provided in the embodiments of this application. Figure 3 for Figure 2 A schematic diagram of the first structure of the mid-to-high frequency amplifier circuit 200. (See diagram below.) Figures 1 to 3 As shown, one embodiment provides a DC broadband composite amplifier device, including: a signal splitter circuit 100, a high-frequency amplifier circuit 200, a low-frequency amplifier circuit 300, and a feedback control circuit 400.

[0024] The signal splitter circuit 100 receives the input signal and splits it into a high-frequency path signal and a low-frequency path signal. The high-frequency amplifier circuit 200 includes an RF power amplifier 210, which has a control terminal, an output terminal, and a common terminal. The control terminal of the RF power amplifier 210 receives the high-frequency path signal, and the output terminal of the RF power amplifier 210 is connected to the signal splitter circuit OUTPUT. The low-frequency amplifier circuit 300 amplifies the low-frequency path signal and generates a low-frequency reference signal. The feedback control circuit 400 includes a current sampling circuit 410 and an integrating amplifier circuit 420. The current sampling circuit 410 is connected to the output terminal of the RF power amplifier 210 and is used to collect the output current of the RF power amplifier 210 and convert it into a voltage feedback signal. The integrating amplifier circuit 420 is connected to the common terminal of the RF power amplifier 210 and is used to adjust the current flowing into the common terminal of the RF power amplifier 210 according to the voltage feedback signal and the low-frequency reference signal, thereby realizing the combined output of the high-frequency signal and the low-frequency signal.

[0025] The signal splitter circuit 100 is a circuit unit that separates a single input signal in the frequency domain. In some embodiments, the signal splitter circuit 100 may include a follower, a buffer, and high-pass and low-pass filter networks to ensure that the high-frequency path signal and the low-frequency path signal enter their respective processing channels.

[0026] like Figure 1 As shown, in this embodiment, the signal splitter circuit 100 is specifically a differential amplifier U2, and the specific structure of the differential amplifier U2 and its connection relationship with other devices can be found in [reference needed]. Figure 1 This will not be elaborated upon here.

[0027] It is understandable that the signal splitter circuit 100 is a circuit unit that converts a single-ended signal into a differential signal with a unity gain A=1. Based on the signal frequency characteristics, it separates the input signal into a high-frequency path signal (usually a signal with a frequency higher than 1MHz) and a low-frequency path signal (usually a signal with a frequency lower than 1MHz) without distortion, and the signal amplitude remains unchanged during the splitting process.

[0028] The high-frequency amplifier circuit 200 is a circuit unit that amplifies the power of the high-frequency path signal and is configured to amplify the high-frequency path signal from a small signal to a large signal that meets the amplitude requirements.

[0029] The low-frequency amplifier circuit 300 is a circuit unit that amplifies the gain of the low-frequency path signal. It is used to amplify the low-frequency path signal with a preset gain to generate a stable low-frequency reference signal, providing a reference for feedback adjustment.

[0030] The feedback control circuit 400 is a circuit unit that realizes closed-loop current regulation. The feedback control unit mainly uses closed-loop logic of sampling, comparison integration, and regulation to combine the high-frequency path signal and the low-frequency path signal for output.

[0031] Specifically, combined output refers to modulating the amplitude changes of a low-frequency signal onto the DC operating point of a high-frequency signal through current control, so that the final output signal has both the rapid change characteristics of high frequency and the large amplitude swing characteristics of low frequency.

[0032] During operation, the RF power amplifier 210 receives the high-frequency path signal and amplifies it. The amplified high-frequency signal is then transmitted to the signal splitter circuit OUTPUT through the output of the RF power amplifier 210. The low-frequency path signal is amplified by the low-frequency amplifier circuit 300 and used as a reference signal input to the integrating amplifier circuit 420. The current sampling circuit 410 monitors the output current of the RF power amplifier 210 in real time and converts it into a voltage feedback signal. The integrating amplifier circuit 420 compares the voltage feedback signal with the low-frequency reference signal. If a deviation exists, the integrating amplifier circuit 420 adjusts the current flowing into the common terminal of the RF power amplifier 210.

[0033] The RF power amplifier 210 can be a transistor or a MOSFET. In this embodiment, the RF power amplifier 210 is a transistor. Specifically, the RF power amplifier 210 is transistor Q1, and the specific structure of transistor Q1 and its connection relationship with other devices can be found in [reference needed]. Figure 1 This will not be elaborated upon here.

[0034] Furthermore, the control terminal of the RF power amplifier 210 is the base of the transistor Q1, the output terminal of the RF power amplifier 210 is the collector of the transistor Q1, and the common terminal of the RF power amplifier 210 is the emitter of the transistor Q1.

[0035] like Figure 1 As shown, the control and output terminals of the RF power amplifier 210 are both connected to bias circuits. One bias circuit may include resistor R7 and impedance L3. The other bias circuit may include resistor R1 and impedance L1. For the specific structure of the two bias circuits and their connections to other devices, please refer to [reference needed]. Figure 1 This will not be elaborated further here. It is understandable that the two bias circuits mentioned above provide stable bias for the RF power amplifier 210, enabling the RF power amplifier 210 to operate in the Class A amplification region, that is, the emitter junction is forward biased and the collector junction is reverse biased.

[0036] like Figure 1As shown, a resistor R16 is connected between the common terminal of the RF power amplifier 210 and the integrating amplifier circuit 420. It can be understood that the RF power amplifier 210 is a Class A RF power amplifier with a common-emitter configuration. According to the transistor small-signal equivalent circuit model analysis, the ratio of R1 / R16 can determine the gain G of the RF power amplifier 210. q1 The output impedance is resistor R1, and high-frequency signal circuits are usually matched to 50Ω, so R1=50Ω.

[0037] In the above implementation, the circuit architecture of signal splitting, independent amplification of high and low frequency signals, and closed-loop merging solves the technical problem in the prior art where the signal generator relies on integrated high-speed operational amplifiers, resulting in insufficient large-signal bandwidth and the inability to output wide-bandwidth DC signals. Specifically, the signal splitting circuit 100 achieves interference-free separation of high and low frequency signals, avoiding mutual suppression between them in traditional single-path amplification; the feedback control circuit 400, through current sampling and integral adjustment, superimposes the high-frequency amplified signal onto the low-frequency reference signal, ensuring gain continuity over the wide bandwidth.

[0038] Figure 4 for Figure 2 A schematic diagram of the second structure of the mid-to-high frequency amplifier circuit 200. (See diagram below.) Figure 4 As shown, in some embodiments, the high-frequency amplifier circuit 200 further includes a high-frequency preamplifier 220, which is used to amplify the high-frequency path signal and output the amplified signal to the control terminal of the radio frequency power amplifier 210.

[0039] The high-frequency preamplifier 220 is an LNA, which is a low-noise amplifier. It is a fixed-gain high-frequency amplifier chip used to perform low-noise pre-amplification on the high-frequency path signal after splitting, improve the signal amplitude and driving capability, and avoid amplification distortion caused by the high-frequency path signal directly entering the RF power amplifier 210.

[0040] The high-frequency preamplifier 220 is specifically operational amplifier U3. For the specific structure of operational amplifier U3 and its connections with other components, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0041] Continue to refer to Figure 4 The high-frequency amplifier circuit 200 includes a high-frequency preamplifier 220 and an RF power amplifier 210. The total gain is the product of the gains of the high-frequency preamplifier 220 and the RF power amplifier 210, where G H =G U3 ×G Q1 Combined with reference Figure 1 G Q1 =R1 / R16, resistor R1 is fixed at 50Ω for high-frequency impedance matching.

[0042] Reference Figure 1 For the high-frequency amplifier circuit 200, the high-frequency path signal output from the signal splitter circuit 100 is coupled to the non-inverting input of operational amplifier U3 through capacitor C8. Capacitor C8 simultaneously filters out residual low-frequency components in the split signal, ensuring the signal purity input to operational amplifier U3. Operational amplifier U3 operates stably under the bias of resistor R6 and inductor L2, performing low-noise pre-amplification on the input high-frequency small signal, with a fixed gain G. u3 This effectively enhances the signal amplitude and driving capability, avoiding amplification saturation or distortion caused by insufficient base drive when a high-frequency small signal is directly input to transistor Q1. The high-frequency signal, pre-amplified by operational amplifier U3, is transmitted to the base of transistor Q1 through resistor R23. At this point, the signal has sufficient driving capability. Under the action of its own bias circuit (resistor R7, inductor L3, resistor R1, inductor L1), transistor Q1 achieves power amplification, raising the signal amplitude to the target level. The amplified high-frequency signal is combined with the low-frequency path signal and output to the signal splitter circuit OUTPUT through the collector of transistor Q1. Simultaneously, the output current of transistor Q1 is sampled by the feedback control circuit 400 and participates in closed-loop regulation to ensure signal stability.

[0043] Thus, this embodiment solves the problems of insufficient driving capability and poor amplification linearity caused by high-frequency small signals directly entering the RF power amplifier 210 by adding a high-frequency preamplifier 220. Specifically, the low-noise characteristics of the high-frequency preamplifier 220 reduce noise interference during high-frequency amplification and ensure the signal-to-noise ratio of the output signal; the fixed gain characteristics stabilize the preamplification gain of the high-frequency path, providing a stable basis for the subsequent gain matching between the high-frequency path and the low-frequency path.

[0044] Figure 5 for Figure 2 A schematic diagram of the feedback control circuit 400. (See diagram below.) Figure 1 , Figure 5 As shown, in some embodiments, the current sampling circuit 410 includes a sampling resistor 411 and a converter 412. The sampling resistor 411 is connected to the output terminal of the radio frequency power amplifier 210, and the two input terminals of the converter 412 are respectively connected to the two ends of the sampling resistor 411. The converter 412 is used to collect the current flowing through the sampling resistor 411 and generate a voltage feedback signal.

[0045] The sampling resistor 411 is specifically resistor R8. For details on the structure of resistor R8 and its connections to other components, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0046] Converter 412 differentially amplifies and converts the voltage drop across sampling resistor 411 into a current-to-voltage signal, transforming the weak sampled voltage into a voltage feedback signal that meets the adjustment requirements of integrating amplifier circuit 420. Converter 412 is specifically operational amplifier U1, and for details on the specific structure of operational amplifier U1 and its connections with other components, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0047] Continue to refer to Figure 1 Resistor R3 is the feedback resistor of converter 412, resistor R5 is the input resistor of converter 412, and the conversion gain of converter 412 is R3 / R5.

[0048] During operation, the RF power amplifier 210 outputs a high-frequency amplified signal, the output current of which is I. out According to Ohm's law, a voltage drop U is generated across the sampling resistor 411 as the current flows through it. R8 =I out ×R8, the voltage drop amplitude is proportional to the output current, realizing the initial conversion of the current signal to a voltage signal. The non-inverting input and inverting input of converter 412 respectively detect the voltage across sampling resistor 411. Since converter 412 constitutes a differential amplifier circuit, its input difference is U. + -U - =U R8 The converter 412 amplifies the input difference according to the gain to generate a voltage feedback signal, which reflects the amplitude change of the output current of the RF power amplifier 210. The voltage feedback signal is transmitted to the inverting input of the integrating amplifier circuit 420 and compared with the low-frequency reference signal to provide accurate feedback for subsequent integral adjustment, ensuring that the output current of the RF power amplifier 210 follows the change of the low-frequency reference signal.

[0049] Thus, the sampling point of the current sampling circuit 410 is directly set at the output end of the RF power amplifier 210, which can collect the output current signal in real time and accurately, providing reliable signal support for feedback closed-loop regulation, thereby ensuring the stability and linearity of the combined output of high-frequency and low-frequency signals.

[0050] like Figure 1 , Figure 5 As shown, in some embodiments, the integrating amplifier circuit 420 includes an error integrator 421 and a control amplifier 422. The error integrator 421 is used to perform integration operations based on the voltage feedback signal and the low-frequency reference signal to generate a control voltage signal. The control amplifier 422 responds to the control voltage signal and thereby adjusts the current flowing into the common terminal of the RF power amplifier 210.

[0051] The error integrator 421 integrates the difference between the voltage feedback signal and the low-frequency reference signal, converting the instantaneous difference into a continuously changing control voltage signal. This avoids regulation oscillations caused by instantaneous fluctuations and ensures the smoothness of the regulation process. Specifically, the error integrator 421 is operational amplifier U4, and for details on the specific structure of operational amplifier U4 and its connections with other components, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0052] The control amplifier 422 converts the control voltage signal output from the error integrator 421 into a current signal. By adjusting its own conduction level, it changes the current flowing into the common terminal of the RF power amplifier 210, thereby controlling the output current of the RF power amplifier 210 and achieving the superposition of the low-frequency reference signal and the high-frequency amplified signal. The control amplifier 422 is specifically a transistor Q2, and for details on the specific structure of transistor Q2 and its connections with other components, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0053] During operation, the error integrator 421 simultaneously receives two input signals: a low-frequency reference signal and a voltage feedback signal. The low-frequency reference voltage serves as the adjustment target, and the voltage feedback signal serves as the actual feedback value. The error integrator 421 detects the difference between the two signals. Based on the principle of integration, the error integrator 421 integrates the difference between the two signals to generate a continuously changing control voltage signal. When the difference between the two signals is positive (i.e., the low-frequency reference signal is greater than the voltage feedback signal), the control voltage signal gradually increases over time. When the difference between the two signals is negative (i.e., the low-frequency reference signal is less than the voltage feedback signal), the control voltage signal gradually decreases over time. When the difference between the two signals is 0, the control voltage signal remains constant, achieving steady-state regulation. The control voltage signal is transmitted to the base of the control amplifier 422. Its base voltage is positively correlated with the conduction level; that is, when the base voltage increases, the base current increases, and the emitter current increases synchronously; when the base voltage decreases, the base current decreases, and the emitter current decreases synchronously. The emitter current of the control amplifier 422 flows into the emitter of the RF power amplifier 210, changing the emitter current of the RF power amplifier 210. According to the current relationship of the transistor, the collector output current of the RF power amplifier 210 changes accordingly, ultimately achieving a difference of 0 between the two signals, thus completing the superposition of the low-frequency reference signal and the high-frequency amplified signal.

[0054] Thus, by cooperating with the error integrator 421 and the control amplifier 422, the technical problems of regulation oscillation and response lag caused by instantaneous fluctuations in feedback regulation in the prior art are solved. The integral operation characteristics of the error integrator 421 can accumulate signal differences, avoiding mis-regulation due to instantaneous interference and ensuring the stability and accuracy of the regulation process. The control amplifier 422 converts the voltage control signal into a current regulation signal, which directly acts on the common terminal of the RF power amplifier 210. The regulation response speed is fast, and it can track the changes of the low-frequency reference signal in real time, realizing the accurate superposition of high-frequency and low-frequency signals. In addition, the integrating amplifier circuit 420, the current sampling circuit 410, and the low-frequency amplifier circuit 300 form a closed-loop collaboration, so that the output signal of the device not only has high-frequency broadband characteristics, but also maintains stable amplitude and linearity, effectively solving the problem of gain discontinuity in the crossband, and further improving the output quality of DC broadband large signals.

[0055] like Figure 1 As shown, in some embodiments, the collector of the control amplifier 422 is connected to a -5V voltage source, the base of the control amplifier 422 is connected to the error integrator 421, and the emitter of the control amplifier 422 is connected to the common terminal of the radio frequency power amplifier 210.

[0056] When the voltage feedback signal is less than the low-frequency reference signal, the error integrator 421 outputs a control voltage signal, which increases the base voltage of the control amplifier 422, increases the conduction degree of the control amplifier 422, increases the current flowing into the common terminal of the RF power amplifier 210, and causes the output current of the RF power amplifier 210 to increase until the voltage feedback signal is equal to the low-frequency reference signal.

[0057] During operation, the control voltage signal output by the error integrator 421 is transmitted to the base of the control amplifier 422. The collector of the control amplifier 422 is connected to a -5V voltage source. Under the influence of the base voltage, the emitter junction is forward biased and the collector junction is reverse biased, and the control amplifier 422 operates in the amplification region. The base current I... B2 Amplified into emitter current I E2 This achieves the conversion and amplification of voltage signals into current signals. The emitter current I of the control amplifier 422 is... E2 The current flows into the emitter of the RF power amplifier 210, causing the emitter current I of the RF power amplifier 210 to... E1 =I E2 +I B1 , where I B1 For the base current of the RF power amplifier 210, since I E2 Much greater than I B1 I E1 Mainly composed of I E2Control, thereby causing the collector output current I of the RF power amplifier 210 to... C1 ≈I E1 That is, follow I E2 change.

[0058] When the collector output current of the RF power amplifier 210 decreases due to load changes or signal fluctuations, the current flowing through the sampling resistor 411 decreases synchronously, the voltage drop across the sampling resistor 411 decreases, and the voltage feedback signal U output by the converter 412 decreases. 1out This also decreases accordingly, therefore the difference between the low-frequency reference signal and the voltage feedback signal is greater than 0, ΔU=U 5out -U 1out >0. The error integrator 421 integrates this difference and outputs a control voltage signal, which increases linearly with time. The integral operation ensures that the control voltage signal does not change abruptly due to instantaneous fluctuations in ΔU, guaranteeing the smoothness of the regulation. After the control voltage signal increases, the base voltage of the control amplifier 422 increases, and the base current I... B2 As the voltage increases, the conduction level of the control amplifier 422 increases, and the emitter current I of the control amplifier 422 increases. E2 Synchronously increase. Control amplifier 422's emitter current I E2 Increase the current I flowing into the emitter of the RF power amplifier 210 E1 Increase, according to the transistor current relationship I C1 ≈I E1 The collector output current I of the RF power amplifier 210 C1 Consequently, the collector output current I of the RF power amplifier 210 increases; C1 Increasing the voltage across sampling resistor 411 increases the current flowing through it, thus increasing the voltage drop across it. This, in turn, increases the output voltage U of converter 412. 1out As the system increases synchronously, ΔU gradually decreases; when U 1out =U 5out When ΔU=0, the integration operation of the error integrator 421 stops, the control voltage signal remains constant, and the conduction level of the control amplifier 422 stabilizes. E2 unchanged, I C1 Once the target value is stabilized, the closed-loop adjustment is complete, and the system enters a state of equilibrium.

[0059] like Figure 5 As shown, in some embodiments, the low-frequency amplifier circuit 300 includes a low-frequency gainer 310, which is used to amplify the low-frequency path signal.

[0060] The low-frequency gain converter 310 linearly amplifies the low-frequency path signal. The amplification factor can be adjusted by the external resistor parameter, and the output signal serves as the low-frequency reference signal U. 5outIts amplitude determines the amplitude of the low-frequency component in the combined output signal. The low-frequency gainer 310 is specifically operational amplifier U5, and for the specific structure of operational amplifier U5 and its connections with other devices, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0061] The gain of the low-frequency gainer 310 is the amplification factor determined by resistors R21, R19, R26, and R17. Specifically, By adjusting the resistance values ​​of these resistors, the amplification factor of low-frequency signals can be flexibly set to adapt to different output requirements.

[0062] In some possible implementations, the device also includes a zeroing circuit 500, which includes an adjustable voltage source and an adjusting resistor. One end of the adjusting resistor is connected to the adjustable voltage source, and the other end of the adjusting resistor is connected to an integrating amplifier circuit 420, which is used to adjust the DC bias voltage of the signal splitter circuit OUTPUT so that the DC potential at the output terminal is zero.

[0063] The adjustable voltage source is specifically offset_VCC, and for its specific structure and connections with other devices, please refer to [reference needed]. Figure 1 This will not be elaborated upon here.

[0064] The adjusting resistor is specifically resistor RV1, and please refer to [reference needed] for the specific structure of resistor RV1 and its connection relationship with other components. Figure 1 This will not be elaborated upon here.

[0065] It is understandable that the DC bias voltage refers to the DC potential of the signal shunt circuit OUTPUT when there is no signal input. Ideally, it should be 0V. In reality, due to the difference in VBE of transistors, the deviation of component parameters such as the input offset voltage of operational amplifiers, the DC bias voltage will not be zero and needs to be compensated by a zero-adjustment circuit.

[0066] Furthermore, because the DC broadband composite amplifier in this embodiment has a crossband after combining, it is necessary to adjust the gain of the high-frequency amplifier circuit 200 to be equal to the gain of the low-frequency amplifier circuit 300 and the feedback control circuit 400 to solve the problem of gain discontinuity in the crossband.

[0067] First, regarding the error integrator 421, let the output be U. out The voltage of the low-frequency reference signal is U. 5out The voltage of the voltage feedback signal is U. 1out With a gain of Gu4, the virtual open circuit can be used to determine the operation. , .

[0068] Secondly, adjust the zero voltage source offset_VCC by adjusting the OUTPUT bias voltage of the signal branch circuit to zero through the adjustable resistor RV1.

[0069] The total gain of the low-frequency signal amplification path is: G L =G u2 ×G u5 ×G u4 The specific formula is as follows: .

[0070] The total gain of the high-frequency signal amplification path is: G H =G U3 ×G Q1 The specific formula is as follows: To facilitate the calculation of the gain value, let R 21 =R 19 R 26 =R 17 R3=R5, R 14 +R 24 =R 20 Simplifying, we get: Gu3×50Ω / R16=50Ω / R8, Gu3=R16 / R8.

[0071] Therefore, we only need to make the ratio of R16 to R8 equal to the high-frequency amplifier G. U3 Gain is sufficient.

[0072] The signal amplification method implemented by the DC broadband composite amplifier in this embodiment includes: It receives input signals and divides them into high-frequency and low-frequency path signals. The high-frequency path signal is transmitted to the high-frequency amplification module for amplification, and the signal is output to the signal splitter circuit OUTPUT through the RF power amplifier 210. The low-frequency path signal is transmitted to the low-frequency amplification module for amplification to obtain the low-frequency reference signal; The high-frequency amplification module's output current at the signal splitter circuit OUTPUT is acquired, and the acquired output current is converted into a feedback voltage signal. The low-frequency reference signal is compared with the feedback voltage signal and integrated to generate the control voltage signal; By adjusting the operating current of the high-frequency amplifier module using a control voltage signal, the DC operating point of the high-frequency amplifier module is stabilized, and the low-frequency path signal is superimposed onto the signal splitter circuit OUTPUT to achieve DC broadband large signal output.

[0073] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0074] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0076] The terms "coupled," "connected," or "connected" in the instruction manual include both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as a connection made through an electrically conductive medium, which may have parasitic inductance or capacitance. An indirect connection may also include connections made through other active or passive devices to achieve the same or similar functional purpose, such as connections made through circuits or components such as switches or follower circuits.

[0077] In the detailed description of this specification, reference is made to the accompanying drawings, which form a part thereof, wherein like reference numerals always denote like parts, and wherein exemplary embodiments are shown by way of example that may be implemented. It should be understood that other embodiments may be utilized, and structural or logical changes may be made, without departing from the scope of this application. Therefore, the following detailed description should not be considered limiting.

[0078] The various operations in the specification may be described sequentially as multiple discrete actions or operations in a manner most conducive to understanding the claimed subject matter. However, the order of description should not be construed as implying that these operations must be sequentially related. Specifically, these operations may not be performed in the order presented. The described operations may be performed in a different order than in the described embodiments. Various additional operations may be performed in additional embodiments and / or the described operations may be omitted.

[0079] Various components and devices may be referred to or shown in the singular (e.g., “MOS transistor”, “transistor”, “switch”, etc.) in this document, but only for the convenience of discussion, and any element referred to in the singular may include multiple such elements as taught herein.

[0080] The above are merely preferred embodiments of this application and do not constitute any limitation on this application. Any person skilled in the art can make many possible variations and modifications to the technical solution of this application, or modify it into equivalent embodiments, without departing from the scope of the technical solution of this application. Therefore, all equivalent changes made based on the shape, structure, and principle of this application without departing from the content of the technical solution of this application should be covered within the protection scope of this application.

Claims

1. A DC broadband composite amplifier, characterized in that, include: A signal splitter circuit is used to receive an input signal and split the input signal into a high-frequency path signal and a low-frequency path signal; A high-frequency amplifier circuit includes a radio frequency power amplifier, which has a control terminal, an output terminal, and a common terminal. The control terminal of the radio frequency power amplifier is used to receive the high-frequency path signal, and the output terminal of the radio frequency power amplifier is connected to the circuit output terminal. A low-frequency amplifier circuit is used to amplify the low-frequency path signal and generate a low-frequency reference signal; The feedback control circuit includes a current sampling circuit and an integrating amplifier circuit. The current sampling circuit is connected to the output terminal of the radio frequency power amplifier and is used to collect the output current of the radio frequency power amplifier and convert it into a voltage feedback signal. The integrating amplifier circuit is connected to the common terminal of the radio frequency power amplifier and is used to adjust the current flowing into the common terminal of the radio frequency power amplifier according to the voltage feedback signal and the low-frequency reference signal, thereby realizing the combined output of high-frequency and low-frequency signals.

2. The DC broadband composite amplifier according to claim 1, characterized in that, The high-frequency amplifier circuit also includes a high-frequency preamplifier, which is used to amplify the voltage of the high-frequency path signal and output the amplified signal to the control terminal of the radio frequency power amplifier.

3. The DC broadband composite amplifier according to claim 1, characterized in that, The radio frequency power amplifier is a transistor or a MOSFET.

4. The DC broadband composite amplifier according to claim 1, characterized in that, The current sampling circuit includes a sampling resistor and a converter. The sampling resistor is connected to the output terminal of the radio frequency power amplifier. The two input terminals of the converter are respectively connected to the two ends of the sampling resistor. The converter is used to collect the current flowing through the sampling resistor and generate a voltage feedback signal.

5. The DC broadband composite amplifier according to claim 1, characterized in that, The integrating amplifier circuit includes an error integrator and a control amplifier. The error integrator is used to perform integration operations based on the voltage feedback signal and the low-frequency reference signal to generate a control voltage signal. The control amplifier responds to the control voltage signal and thereby adjusts the current flowing into the common terminal of the RF power amplifier.

6. The DC broadband composite amplifier according to claim 5, characterized in that, The control amplifier is a transistor. The collector of the control amplifier is connected to a -5V voltage source, the base of the control amplifier is connected to the error integrator, and the emitter of the control amplifier is connected to the common terminal of the RF power amplifier.

7. The DC broadband composite amplifier according to claim 5, characterized in that, When the voltage feedback signal is less than the low-frequency reference signal, the error integrator outputs a control voltage signal, which increases the base voltage of the control amplifier, increases the conduction degree of the control amplifier, increases the current flowing into the common terminal of the RF power amplifier, and causes the output current of the RF power amplifier to increase until the voltage feedback signal is equal to the low-frequency reference signal.

8. The DC broadband composite amplifier according to claim 1, characterized in that, The low-frequency amplifier circuit includes a low-frequency gain unit, which is used to amplify the low-frequency path signal.

9. The DC broadband composite amplifier according to claim 1, characterized in that, The device further includes a zeroing circuit, which includes an adjustable voltage source and an adjusting resistor. One end of the adjusting resistor is connected to the adjustable voltage source, and the other end of the adjusting resistor is connected to the integrating amplifier circuit for adjusting the DC bias voltage at the circuit output.

10. A signal amplification method implemented by the DC broadband composite amplifier device of claim 1, characterized in that, include: Receives an input signal and divides the input signal into a high-frequency path signal and a low-frequency path signal; The high-frequency path signal is transmitted to the high-frequency amplification module for amplification, and the signal is output to the circuit output terminal through the radio frequency power amplification device. The low-frequency path signal is transmitted to the low-frequency amplification module for amplification to obtain a low-frequency reference signal; The output current of the high-frequency amplification module at the circuit output terminal is collected, and the collected output current is converted into a feedback voltage signal; The low-frequency reference signal is compared with the feedback voltage signal and integrated to generate a control voltage signal; The operating current of the high-frequency amplifier module is adjusted by the control voltage signal to stabilize the DC operating point of the high-frequency amplifier module, and the low-frequency path signal is superimposed on the output terminal of the circuit to achieve DC broadband large signal output.

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