CN216252675U - Push-pull power amplifying circuit and radio frequency front end module - Google Patents
Push-pull power amplifying circuit and radio frequency front end module Download PDFInfo
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- CN216252675U CN216252675U CN202122404694.3U CN202122404694U CN216252675U CN 216252675 U CN216252675 U CN 216252675U CN 202122404694 U CN202122404694 U CN 202122404694U CN 216252675 U CN216252675 U CN 216252675U
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Abstract
The utility model discloses a push-pull power amplifying circuit and a radio frequency front end module, wherein the push-pull power amplifying circuit comprises: the first LC filter circuit is coupled to the output end of the first power amplifier tube and is configured to carry out harmonic suppression on the even harmonic signal of the push-pull power amplifier circuit; the second LC filter circuit is coupled to the output end of the second power amplifying tube and is configured to carry out harmonic suppression on the even harmonic signal of the push-pull power amplifying circuit; the matching filter circuit is coupled between the output end of the first power amplifying tube and the output end of the second power amplifying tube, and is configured to adjust an impedance matching point of a fundamental wave signal of the push-pull power amplifying circuit so as to achieve the purpose of impedance matching.
Description
Technical Field
The utility model relates to the technical field of radio frequency amplification, in particular to a push-pull power amplification circuit and a radio frequency front-end module.
Background
The push-pull power amplifier is an amplifier which utilizes two transistors with the same characteristics to enable the two transistors to work in a B state, wherein one transistor works in a positive half cycle, the other transistor works in a negative half cycle, and then output waveforms of the two transistors are combined together on a load to obtain a complete output waveform.
Push-pull power amplifiers are commonly used in wireless communication systems. However, in the operation process of the existing push-pull power amplifier, due to the influence of some non-linear elements in the push-pull power amplifier, a large harmonic signal is easily generated, and the linearity and the efficiency of the push-pull power amplifier are greatly influenced. Therefore, it is important and difficult to design a push-pull power amplifier to achieve good linearity and efficiency of the push-pull power amplifier.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a push-pull power amplifying circuit and a radio frequency front end module, which aim to solve the problem that the existing push-pull power amplifying circuit is poor in overall performance.
A push-pull power amplifying circuit comprises a first power amplifying tube, a second power amplifying tube, a first LC filter circuit, a second LC filter circuit and a matched filter circuit;
the first LC filter circuit is coupled to the output end of the first power amplifier tube and is configured to perform harmonic suppression on even harmonic signals of the push-pull power amplifier circuit;
the second LC filter circuit is coupled to the output end of the second power amplifier tube and is configured to perform harmonic suppression on the even harmonic signal of the push-pull power amplifier circuit;
the matched filter circuit is coupled between the output end of the first power amplifying tube and the output end of the second power amplifying tube, and is configured to perform harmonic suppression on odd harmonic signals of the push-pull power amplifying circuit and adjust the impedance of a fundamental wave signal of the push-pull power amplifying circuit.
Further, the matched filter circuit comprises a regulating capacitor.
Further, the capacitance value of the adjusting capacitor is inversely related to the frequency of the odd harmonic signal.
Further, the first LC filter circuit is configured to form a first resonance frequency point, and the second LC filter circuit is configured to form a second resonance frequency point.
Further, the first resonance frequency point and the second resonance frequency point are different.
Further, the push-pull power amplifying circuit further comprises a third LC filter circuit and a fourth LC filter circuit;
the third LC filter circuit is coupled to the output end of the first power amplifier tube and is configured to form a third resonant frequency point;
the fourth LC filter circuit is coupled to the output end of the second power amplifier tube and configured to form a fourth resonant frequency point.
Further, the third resonance frequency point and the fourth resonance frequency point are different.
Further, the first LC filter circuit includes a first capacitor and a first inductor connected in series, one end of the first capacitor is coupled to the output end of the first power amplifier tube, the other end of the first capacitor is connected to a first end of the first inductor, and a second end of the first inductor is connected to a ground terminal;
the second LC filter circuit comprises a second capacitor and a second inductor which are connected in series, one end of the second capacitor is coupled to the output end of the second power amplifier tube, the other end of the second capacitor is connected with the first end of the second inductor, and the second end of the second inductor is connected with the grounding end.
A radio frequency front end module comprises a substrate and a push-pull power amplifier chip arranged on the substrate, wherein the push-pull power amplifier chip is provided with the push-pull power amplifier circuit.
Further, the radio frequency front-end module further comprises a first conversion balun arranged on the substrate, the first conversion balun comprises a first input end and a second input end, an output end of the first power amplification tube is connected with the first input end of the first conversion balun through a first transmission line, and an output end of the second power amplification tube is connected with the second input end of the first conversion balun through a second transmission line.
Furthermore, the rf front-end module further includes a feeding power source disposed on the substrate, the feeding power source is coupled to the output terminal of the first power amplifier tube through a first feeding inductor, and the feeding power source is coupled to the output terminal of the second power amplifier tube through a second feeding inductor.
The push-pull power amplification circuit comprises a first power amplification tube, a second power amplification tube, a first LC filter circuit, a second LC filter circuit and a matching filter circuit, wherein the first LC filter circuit is coupled to the output end of the first power amplification tube, meanwhile, the second LC filter circuit is coupled to the output end of the second power tube, and the even harmonic signals are filtered to the ground through the resonance effect of the first LC filter circuit and the second LC filter circuit and the even harmonic signals, so that the aim of performing harmonic suppression on the even harmonic signals of the push-pull power amplification circuit is fulfilled; meanwhile, the matched filter circuit is coupled between the output end of the first power amplifying tube and the output end of the second power amplifying tube, and the matched filter circuit can also adjust the impedance matching point of the fundamental wave signal of the push-pull power amplifying circuit so as to achieve the purpose of impedance matching.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
Fig. 1 is a circuit diagram of a push-pull power amplifier circuit according to an embodiment of the utility model;
FIG. 2 is another circuit diagram of a push-pull power amplifier circuit according to an embodiment of the utility model;
FIG. 3 is another circuit diagram of a push-pull power amplifier circuit according to an embodiment of the utility model;
fig. 4 is a circuit diagram of the rf front-end module according to an embodiment of the utility model.
In the figure: 10. a first power amplifier tube; 20. a second power amplifier tube; 30. a first LC filter circuit; 40. a second LC filter circuit; 50. a third LC filter circuit; 60. a fourth LC filter circuit; 70. a matched filter circuit; 81. a first transmission line; 82. a second transmission line; 83. a first conversion balun.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the utility model to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity to indicate like elements throughout.
It will be understood that when an element or layer is referred to as being "on" …, "adjacent to …," "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on …," "directly adjacent to …," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Spatial relationship terms such as "under …", "under …", "below", "under …", "above …", "above", and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "below …" and "below …" can encompass both an orientation of up and down. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
In the following description, for purposes of explanation, specific details are set forth in order to provide a thorough understanding of the present invention. The following detailed description of the preferred embodiments of the utility model, however, the utility model is capable of other embodiments in addition to those detailed.
The present embodiment provides a push-pull power amplifier circuit, as shown in fig. 1, including a first power amplifier tube 10, a second power amplifier tube 20, a first LC filter circuit 30, a second LC filter circuit 40, and a matched filter circuit 70; a first LC filter circuit 30 coupled to an output terminal of the first power amplifying transistor 10, configured to perform harmonic suppression on an even harmonic signal of the push-pull power amplifying circuit; a second LC filter circuit 40 coupled to an output terminal of the second power amplifier tube 20, configured to perform harmonic suppression on the even harmonic signal of the push-pull power amplifier circuit; and a matched filter circuit 70 coupled between the output terminal of the first power amplifier tube 10 and the output terminal of the second power amplifier tube 20, configured to perform harmonic suppression on the odd harmonic signal of the push-pull power amplifier circuit and adjust the impedance of the fundamental wave signal of the push-pull power amplifier circuit.
The first power amplifier tube 10 and the second power amplifier tube 20 may be BJT transistors (e.g., HBT transistors) or field effect transistors. Preferably, the first power amplifier tube 10 and the second power amplifier tube 20 are BJT transistors, and the current amplification effect of the transistors can be applied to application scenarios with higher power amplification requirements. Specifically, a first input terminal of a first power amplifier tube 10 in the push-pull power amplifier circuit may input a first differential signal, and a second input terminal of a second power amplifier tube 20 may input a second differential signal; the first power amplifier tube 10 amplifies the input first differential signal and outputs a first differential amplified signal; the first power amplifier tube 10 amplifies the input second differential signal and outputs the second differential amplified signal. The amplification factor of the first differential signal is determined by the amplification factor of the first power amplifier tube 10, and the amplification factor of the second differential signal is determined by the amplification factor of the second power amplifier tube 20. The amplification factor of the first differential signal is the same as the amplification factor of the second differential signal.
In a specific embodiment, the push-pull power amplifier circuit generally further includes an input conversion circuit, where the input conversion circuit includes an input conversion balun configured to receive an unbalanced radio frequency input signal and convert the unbalanced radio frequency input signal into a balanced first differential signal and a balanced second differential signal, the first differential signal is input to the first input terminal of the first power amplifier tube 10, the second differential signal is input to the second input terminal of the second power amplifier tube 20, the first power amplifier tube 10 amplifies the received first differential signal, and the second power amplifier tube 20 amplifies the received second differential signal.
Specifically, the first LC filter circuit 30 is a circuit formed by connecting an inductor and a capacitor in series. Similarly, the second LC filter circuit 40 is also a circuit formed by connecting an inductor and a capacitor in series. Referring to fig. 2 below, the first LC filter circuit 30 includes a first capacitor C31 and a first inductor L31 connected in series. A first terminal of the first capacitor C31 is coupled to the output terminal of the first power amplifier tube 10, a second terminal thereof is connected to a first terminal of the first inductor L31, and a second terminal of the first inductor L31 is connected to the ground terminal. The second LC filter circuit 40 includes a second capacitor C41 and a second inductor L41 connected in series. A first terminal of the second capacitor C41 is coupled to the output terminal of the second power amplifier tube 20, a second terminal thereof is connected to the first terminal of the second inductor L41, and a second terminal of the second inductor L41 is connected to the ground terminal.
In this embodiment, the even harmonic signal may be at least one of any even harmonic such as a second harmonic signal, a fourth harmonic signal, or a sixth harmonic signal. The odd harmonic signal may be at least one of any odd harmonic such as a third harmonic signal, a fifth harmonic signal, or a seventh harmonic signal. It can be understood that, in the present embodiment, the first LC filter circuit 30 and the second LC filter circuit 40 may filter a second harmonic signal in the push-pull power amplifier circuit, or filter a fourth harmonic signal in the push-pull power amplifier circuit, or filter a sixth harmonic signal in the push-pull power amplifier circuit, or filter an even harmonic signal in any one or any combination of the push-pull power amplifier circuits. It should be noted that the even harmonic signal filtered by the first LC filter circuit 30 and the even harmonic signal filtered by the second LC filter circuit 40 may be the same or different. For example: the first LC filter circuit 30 filters out second harmonic signals in the push-pull power amplification circuit, and the second LC filter circuit 40 filters out fourth harmonic signals in the push-pull power amplification circuit; or, the first LC filter circuit 30 filters the second harmonic signal in the push-pull power amplifier circuit, and the second LC filter circuit 40 filters the second harmonic signal in the push-pull power amplifier circuit.
Similarly, the matched filter circuit 70 in this embodiment may filter only the third harmonic signal in the push-pull power amplifier circuit, or filter only the fifth harmonic signal in the push-pull power amplifier circuit, or filter all the odd harmonic signals in the push-pull power amplifier circuit.
In particular, even harmonic signals or odd harmonic signals in the push-pull power amplifying circuit are generated due to the influence of some non-linear elements (such as amplifying transistors) in the push-pull power amplifying circuit, so that the overall performance of the push-pull power amplifying circuit is influenced. In this example, the first differential amplified signal amplified by the first power amplifier tube 10 and the second differential amplified signal amplified by the second power amplifier tube 20 are mixed with the harmonic signal to be filtered. Therefore, the even harmonic signal in the push-pull power amplifying circuit is filtered by coupling the first LC filter circuit 30 to the output end of the first power amplifying tube 10 and coupling the second LC filter circuit 40 to the output end of the second power amplifying tube 20, so that the even harmonic signal is filtered to the ground by the resonance effect of the first LC filter circuit 30 and the second LC filter circuit 40.
For example, in a practical application scenario of the push-pull power amplifier circuit, the second harmonic signal has a large influence on the linearity and stability of the push-pull power amplifier circuit, and therefore, the first LC filter circuit 30 and the second LC filter circuit 40 in this embodiment are mainly used for filtering the second harmonic signal. For example, the resonance frequency points of the first LC filter circuit 30 and the second LC filter circuit 40 may be set to the resonance frequency points corresponding to the second harmonic signals; therefore, even harmonic signals in the push-pull power amplifying circuit are filtered to the ground, and the harmonic performance of the push-pull power amplifying circuit is improved.
As an example, even harmonic signals among the harmonic signals of the push-pull power amplifying circuit are mainly subjected to harmonic suppression by the first LC filter circuit 30 and the second LC filter circuit 40. For the odd harmonic signals, in this example, the harmonic suppression of the odd harmonic signals of the push-pull power amplifying circuit is mainly realized by the matched filter circuit 70 coupled between the output terminal of the first power amplifying transistor 10 and the output terminal of the second power amplifying transistor 20. Further, the matched filter circuit 70 in the present application can also adjust the impedance of the fundamental wave signal of the push-pull power amplifying circuit. The adjustment of the impedance of the fundamental wave signal of the push-pull power amplification circuit is mainly embodied as the adjustment of the imaginary part of the impedance of the fundamental wave signal of the push-pull power amplification circuit, so that the impedance matching is realized.
In one embodiment, since the first power amplifier tube 10 and the second power amplifier tube 20 in the push-pull power amplifier circuit respectively operate in the positive half cycle and the negative half cycle, the odd harmonic signals in the positive half cycle and the odd harmonic signals in the negative half cycle are cancelled by coupling the matched filter circuit 70 between the output terminal of the first power amplifier tube 10 and the output terminal of the second power amplifier tube 20, so as to achieve the purpose of performing harmonic suppression on the odd harmonic signals in the push-pull power amplifier circuit. Meanwhile, the matched filter circuit 70 coupled between the output terminal of the first power amplifier tube 10 and the output terminal of the second power amplifier tube 20 can be further used to adjust the imaginary part of the fundamental signal impedance for the purpose of impedance matching.
In this embodiment, the push-pull power amplifier circuit includes a first power amplifier tube 10, a second power amplifier tube 20, a first LC filter circuit 30, a second LC filter circuit 40 and a matched filter circuit 70, wherein the first LC filter circuit 30 is coupled to the output end of the first power amplifier tube 10, and meanwhile, the second LC filter circuit 40 is coupled to the output end of the second power amplifier tube, and the first LC filter circuit 30 and the second LC filter circuit 40 perform a resonance effect with an even harmonic signal to filter the even harmonic signal to the ground, so as to filter the even harmonic signal in the push-pull power amplifier circuit; meanwhile, the matched filter circuit 70 is coupled between the output end of the first power amplifier tube 10 and the output end of the second power amplifier tube 20, so that the odd harmonic signals of the positive half period and the odd harmonic signals of the negative half period are mutually offset, and the purpose of performing harmonic suppression on the odd harmonic signals of the push-pull power amplifier circuit is achieved. Meanwhile, the matched filter circuit 70 coupled between the output terminal of the first power amplifier tube 10 and the output terminal of the second power amplifier tube 20 can be further used to adjust the imaginary part of the fundamental signal impedance for the purpose of impedance matching. In the present embodiment, the first LC filter circuit 30, the second LC filter circuit 40 and the matched filter circuit 70 work together, so that the push-pull power amplifier circuit can be in different operation types, and the linearity and efficiency of the push-pull power amplifier circuit in different operation types are ensured.
In one embodiment, as shown in FIG. 2, the matched filter circuit 70 includes a tuning capacitor C71.
As an example, the matched filter circuit 70 includes a tuning capacitor C71, one end of the tuning capacitor C71 is coupled to the output terminal of the first power amplifier tube 10, and the other end is coupled to the output terminal of the second power amplifier tube 20, so as to cancel the odd harmonic signals of the positive half period of the harmonic signals amplified and outputted by the first power amplifier tube 10 and the odd harmonic signals of the negative half period of the harmonic signals amplified and outputted by the second power amplifier tube 20, thereby achieving the purpose of performing harmonic suppression on the odd harmonic signals of the push-pull power amplifier circuit. Meanwhile, when the push-pull power amplifying circuit works, based on the impedance matching principle, the capacitance value of the adjusting capacitor C71 can be reasonably set to adjust the imaginary part of the fundamental wave signal impedance, so that the characteristic impedance presented by the adjusting capacitor C71 meets the requirement of impedance matching, and the purpose of impedance matching is achieved.
In another embodiment, the matched filter circuit 70 further includes a first adjusting capacitor and a second adjusting capacitor, one end of the first adjusting capacitor is connected to the output terminal of the first power amplifier tube 10, the other end of the first adjusting capacitor is connected to the ground terminal, one end of the second adjusting capacitor is connected to the output terminal of the second power amplifier tube 20, and the other end of the second adjusting capacitor is connected to the ground terminal. It should be noted that the principle of implementing harmonic suppression on odd harmonic signals and adjusting the impedance of the fundamental wave signal by the first adjusting capacitor and the second adjusting capacitor is substantially the same as the principle of implementing harmonic suppression on odd harmonic signals and adjusting the impedance of the fundamental wave signal by the adjusting capacitor C71, and repeated description is omitted here.
In this embodiment, the matched filter circuit 70 includes a tuning capacitor C71, and one end of the tuning capacitor C71 is coupled to the output terminal of the first power amplifier tube 10, and the other end of the tuning capacitor C71 is coupled to the output terminal of the second power amplifier tube 20, so that the capacitance value of the tuning capacitor C71 is reasonably set, thereby achieving harmonic suppression of the odd harmonic signals of the push-pull power amplifier circuit, and simultaneously meeting the requirement of impedance matching, so as to achieve the purpose of impedance matching.
Further, in one embodiment, the capacitance of the tuning capacitor C71 is inversely related to the frequency of the odd harmonic signal.
In particular, in order to filter out the odd harmonic signals. In this example, the matched filter circuit 70 needs to satisfy that the capacitive reactance of the adjusting capacitor C71 is small enough, that is, the capacitive reactance of the adjusting capacitor C71 is ensured to be less than 10 ohms, so as to be able to filter out the odd harmonic signals.
In one embodiment, assuming that the capacitance of the adjusting capacitor C71 is any capacitance value from 0 to 10 ohms, for example, 5 ohms, the capacitance is calculated according to the following formula:
wherein Z iscoTo adjust the capacitive reactance, f, of the capacitor C71oFrequency of odd harmonic signals, CoIn order to adjust the capacitance of the capacitor C71, it can be seen that the capacitance of the adjusting capacitor C71 can be maintained at 5 ohms until the capacitance of the adjusting capacitor C71 is smaller as the frequency of the odd harmonic signal is larger, on the premise that the capacitance of the adjusting capacitor C71 is 5 ohms, and thus it can be seen that the capacitance of the adjusting capacitor C71 is inversely related to the frequency of the odd harmonic signal.
In this embodiment, in order to release the odd harmonic signal in the push-pull power amplifying circuit to the ground and achieve the effect of suppressing the odd harmonic signal, it is required to ensure that the capacitive reactance of the adjusting capacitor C71 is less than 10 ohms, and in the case that the value of the capacitive reactance of the adjusting capacitor C71 is determined, the calculation formula of the capacitive reactance is as follows:
it can be seen that the capacitance of the tuning capacitor C71 is inversely related to the frequency of the odd harmonic signal.
In one embodiment, the first LC filter circuit 30 is configured to form a first resonant frequency point, and the second LC filter circuit 40 is configured to form a second resonant frequency point.
The first resonant frequency point is a resonant frequency point formed by the first capacitor C31 and the first inductor L31 in the first LC filter circuit 30. The first resonant frequency point is mainly determined by the capacitance value of the first capacitor C31 and the inductance value of the first inductor L31. The second resonance frequency point is a resonance frequency point formed by the second capacitor C41 and the second inductor L41 in the second LC filter circuit 40. The second resonant frequency point is mainly determined by the capacitance value of the second capacitor C41 and the inductance value of the second inductor L41. In the present embodiment, the first resonance frequency point and the second resonance frequency point may be the same or different.
In one embodiment, if the capacitance of the first capacitor C31 and the inductance of the first inductor L31 are the same as the capacitance of the second capacitor C41 and the inductance of the second inductor L41, the first resonant frequency point and the second resonant frequency point are the same. If the capacitance of a capacitor and the inductance of the first inductor L31 are different from the capacitance of the second capacitor C41 and the inductance of the second inductor L41, the first resonant frequency point and the second resonant frequency point are different. In the present embodiment, the first LC filter circuit 30 and the second LC filter circuit 40 are mainly used for performing harmonic suppression on the even harmonic signal of the push-pull power amplifier circuit, and therefore, the formed first resonant frequency point and the second resonant frequency point both belong to the frequency point corresponding to the even harmonic signal.
In one embodiment, if it is known that the frequency point corresponding to the second harmonic signal is 2f0 and the frequency point corresponding to the fourth harmonic signal is 4f0, then to perform harmonic suppression on the second harmonic signal and the fourth harmonic signal, the harmonic suppression can be performed according to the formula of calculating the resonant frequency:
reasonably setting first LC filteringThe inductance value of the first inductor L31 and the capacitance value of the first capacitor C31 in the circuit 30 make the first resonant frequency point formed by the first inductor L31 and the first capacitor C31 the same as the frequency point 2f0 corresponding to the second harmonic signal, and the inductance value of the second inductor L41 and the capacitance value of the second capacitor C41 in the second LC filter circuit 40 are reasonably set, so that the second resonant frequency point formed by the second inductor L41 and the second capacitor C41 the same as the frequency point 4f0 corresponding to the fourth harmonic signal, thereby realizing harmonic suppression of the second harmonic signal and the fourth harmonic signal of the push-pull power amplifier circuit.
In another embodiment, if it is found that the second harmonic signal has a large influence on the push-pull power amplifier circuit, and other even harmonic signals have a small influence on the push-pull power amplifier circuit and can be almost omitted, the inductance value of the first inductor L31 and the capacitance value of the first capacitor C31 in the first LC filter circuit 30 may be reasonably set such that the first resonant frequency point formed by the first inductor L31 and the first capacitor C31 is the same as the frequency point 2f0 corresponding to the second harmonic signal, and the inductance value of the second inductor L41 and the capacitance value of the second capacitor C41 in the second LC filter circuit 40 are reasonably set such that the second resonant frequency point formed by the second inductor L41 and the second capacitor C41 is also the same as the frequency point 2f0 corresponding to the second harmonic signal, and the second harmonic signal of the push-pull power amplifier circuit is harmonic suppressed by the first LC filter circuit 30 and the second LC filter circuit 40, thereby enhancing the effect of harmonic suppression on the second harmonic signal.
In the present embodiment, the first LC filter circuit 30 is configured to form a first resonance frequency point, and the second LC filter circuit 40 is configured to form a second resonance frequency point. In this example, the first resonance frequency point and the second resonance frequency point may be different or the same. When the first resonance frequency point and the second resonance frequency point are different, even harmonic signals with different frequencies in the push-pull power amplification circuit can be filtered, and therefore even harmonic suppression in a wider frequency band range is achieved.
In one embodiment, as shown in fig. 3, the push-pull power amplifying circuit further includes a third LC filter circuit 50 and a fourth LC filter circuit 60; a third LC filter circuit 50 coupled to an output terminal of the first power amplifying transistor 10, configured to form a third resonance frequency point; and a fourth LC filter circuit 60 coupled to an output terminal of the second power amplifying transistor 20 and configured to form a fourth resonance frequency point.
Specifically, the third LC filter circuit 50 includes a third capacitor C51 and a third inductor L51 connected in series. A first terminal of the third capacitor C51 is coupled to the output terminal of the first power amplifier tube 10, a second terminal thereof is connected to the first terminal of the third inductor L51, and a second terminal of the third inductor L51 is connected to the ground terminal. The fourth LC filter circuit 60 includes a fourth capacitor C61 and a fourth inductor L61 connected in series. A first terminal of the fourth capacitor C61 is coupled to the output terminal of the second power amplifier tube 20, a second terminal thereof is connected to the first terminal of the fourth inductor L61, and a second terminal of the fourth inductor L61 is connected to the ground terminal.
Likewise, the third resonance frequency point and the fourth resonance frequency point can be formed by reasonably setting the capacitance value of the third capacitor C51 and the inductance value of the third inductor L51 in the third LC filter circuit 50, and the capacitance value of the fourth capacitor C61 and the inductance value of the fourth inductor L61 in the fourth LC filter circuit 60, so as to suppress even harmonics in the push-pull power amplifier circuit.
In the present embodiment, in order to further achieve suppression of even harmonics in a wider frequency band range, in the present example, the third LC filter circuit 50 is configured to form a third resonance frequency point by being coupled to the output terminal of the first power amplifier tube 10, and the fourth LC filter circuit 60 is configured to form a fourth resonance frequency point by being coupled to the output terminal of the second power amplifier tube 20. Likewise, the third resonance frequency point and the fourth resonance frequency point may be the same, or different. In this embodiment, the principle of harmonic suppression performed by the third LC filter circuit 50 and the fourth LC filter circuit 60 is the same as the principle of harmonic suppression performed by the first LC filter circuit 30 and the second LC filter circuit 40, and redundant description is not repeated here.
In one embodiment, if the first resonant frequency point, the second resonant frequency point, the third resonant frequency point and the fourth resonant frequency point are different; under the combined action of the first LC filter circuit 30, the second LC filter circuit 40, the third LC filter circuit 50 and the fourth LC filter circuit 60, harmonic suppression can be performed on four even harmonic signals with different frequencies in the push-pull power amplification circuit, so that suppression of even harmonics can be achieved in a wider frequency band range.
In another specific embodiment, if the first resonance frequency point and the second resonance frequency point are the same, the third resonance frequency point and the fourth resonance frequency point are the same, but the first resonance frequency point and the second resonance frequency point are different from the third resonance frequency point and the fourth resonance frequency point, under the combined action of the first LC filter circuit 30, the second LC filter circuit 40, the third LC filter circuit 50 and the fourth LC filter circuit 60, harmonic suppression can be performed on even harmonic signals of two different frequencies in the push-pull power amplification circuit, so that while the effect of harmonic suppression is ensured, suppression of even harmonic can be realized in a wider frequency band range.
It should be noted that, in order to realize suppression of even harmonics in a wider frequency band range without considering the cost and the occupied area of the push-pull power amplifier circuit, a plurality of LC filter circuits may be connected to the output terminal of the first power amplifier tube 10 and the output terminal of the second power amplifier tube 20 to form a plurality of different resonant frequency points, so as to realize harmonic suppression and enhanced harmonic suppression in a wider frequency band range.
In a practical application scenario, the first capacitor C31 in the first LC filter circuit 30, the second capacitor C41 in the second LC filter circuit 40, the third capacitor C51 in the third LC filter circuit 50, and the third capacitor C51 in the fourth LC filter circuit 60 are disposed on a chip, and the first inductor L31 in the first LC filter circuit 30, the second inductor L41 in the second LC filter circuit 40, the third inductor L51 in the third LC filter circuit 50, and the third inductor L51 in the fourth LC filter circuit 60 are disposed on a substrate outside the chip. The connected capacitor and the inductor can be connected through binding wires. In this embodiment, the quality factor Q of the push-pull power amplifier circuit can be improved without affecting the harmonic suppression effect by disposing the capacitor in the chip. Because the occupation area of the inductor is often very big, the inductor is arranged on the substrate outside the chip, so that the occupation area of the chip is reduced, and integration is utilized.
The embodiment provides a radio frequency front-end module, which comprises a substrate and a push-pull power amplifier chip arranged on the substrate, wherein the push-pull power amplifier chip is provided with a push-pull power amplifier circuit as in the above embodiment, and is used for improving the harmonic suppression performance of the radio frequency front-end module.
In an embodiment, as shown in fig. 4, the rf front-end module further includes a first converting balun 83 disposed on the substrate (not shown), the first converting balun 83 includes a first input terminal and a second input terminal, the output terminal of the first power amplifier tube 10 is connected to the first input terminal of the first converting balun 83 through a first transmission line 81, and the output terminal of the second power amplifier tube 20 is connected to the second input terminal of the first converting balun 83 through a second transmission line 82.
In this embodiment, the rf front-end module further includes a first converting balun 83 disposed on the substrate for impedance matching of the push-pull power amplifying circuit, in this example, the first converting balun 83 includes a first input terminal and a second input terminal, an output terminal of the first power amplifying tube 10 is connected to the first input terminal of the first converting balun 83 through a first transmission line 81, an output terminal of the second power amplifying tube 20 is connected to the second input terminal of the first converting balun 83 through a second transmission line 82, and due to the matching filter circuit 70 in the push-pull power amplifying circuit, one end is coupled to the output terminal of the first power amplifying tube 10, and the other end is coupled to the output terminal of the second power amplifying tube 20.
The first conversion balun 83 is a device provided in the push-pull power amplification circuit for performing radio frequency signal conversion, or a device provided in the push-pull power amplification circuit for performing impedance matching on a radio frequency signal. In this example, the first conversion balun 83 may be a discrete balun or an integrated balun, and an appropriate balun may be autonomously selected according to actual requirements.
In an embodiment, as shown in fig. 4, the rf front-end module further includes a feeding power source disposed on the substrate, the feeding power source is coupled to the output terminal of the first power amplifying tube 10 through a first feeding inductor L91, and the feeding power source is coupled to the output terminal of the second power amplifying tube 20 through a second feeding inductor L92.
As an example, the rf front end module further includes a feeding power source disposed on the substrate, in this example, the feeding power source is coupled to the output terminal of the first power amplifying tube 10 through a first feeding inductor L91, and the feeding power source is coupled to the output terminal of the second power amplifying tube 20 through a second feeding inductor L92, and configured to feed power to the first power amplifying tube 10 and the second power amplifying tube 20. It should be noted that, since the occupied areas of the first feeding inductor L91 and the second feeding inductor L92 are often large, the first feeding inductor L91 and the second feeding inductor L92 are disposed on the substrate outside the push-pull power amplifier chip, that is, the first feeding inductor L91 and the second feeding inductor L92 are disposed on the substrate, so that the area of the push-pull power amplifier chip is reduced, and the manufacturing cost of the push-pull power amplifier chip is reduced.
In this embodiment, the rf front-end module further includes a power supply disposed on the substrate, the power supply is coupled to the output terminal of the first power amplifier tube 10 through a first power supply inductor L91, and the power supply is coupled to the output terminal of the second power amplifier tube 20 through a second power supply inductor L92, and is configured to supply power to the first power amplifier tube 10 and the second power amplifier tube 20, so as to ensure the normal operation of the push-pull power amplifier chip.
In another embodiment, the first feeding inductor L91 and the second feeding inductor L92 may also be replaced by transmission lines, and since the area occupied by the transmission lines is much smaller than that occupied by the inductors in the chip or circuit board design, the requirement of radio frequency front end module integration is favorably met; moreover, the transmission line is adopted to replace the first feeding inductor L91 and the second feeding inductor L92, so that the problem that the insertion loss of the load line is poor due to the first feeding inductor L91 and the second feeding inductor L92 can be effectively avoided, the insertion loss can be effectively reduced, and the overall power conversion efficiency and the output power of the push-pull power amplification circuit are guaranteed.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (11)
1. A push-pull power amplifying circuit is characterized by comprising a first power amplifying tube, a second power amplifying tube, a first LC filter circuit, a second LC filter circuit and a matched filter circuit;
the first LC filter circuit is coupled to the output end of the first power amplifier tube and is configured to perform harmonic suppression on even harmonic signals of the push-pull power amplifier circuit;
the second LC filter circuit is coupled to the output end of the second power amplifier tube and is configured to perform harmonic suppression on the even harmonic signal of the push-pull power amplifier circuit;
the matched filter circuit is coupled between the output end of the first power amplifying tube and the output end of the second power amplifying tube, and is configured to perform harmonic suppression on odd harmonic signals of the push-pull power amplifying circuit and adjust the impedance of a fundamental wave signal of the push-pull power amplifying circuit.
2. Push-pull power amplification circuit as claimed in claim 1 wherein the matched filter circuit comprises a tuning capacitor.
3. The push-pull power amplification circuit of claim 2, wherein a capacitance value of the adjustment capacitor is inversely related to a frequency of the odd harmonic signal.
4. The push-pull power amplification circuit of claim 1, wherein the first LC filter circuit is configured to form a first resonant frequency point and the second LC filter circuit is configured to form a second resonant frequency point.
5. The push-pull power amplification circuit of claim 4, wherein the first resonance frequency point and the second resonance frequency point are different.
6. The push-pull power amplification circuit of claim 1, further comprising a third LC filter circuit and a fourth LC filter circuit;
the third LC filter circuit is coupled to the output end of the first power amplifier tube and is configured to form a third resonant frequency point;
the fourth LC filter circuit is coupled to the output end of the second power amplifier tube and configured to form a fourth resonant frequency point.
7. The push-pull power amplifying circuit as claimed in claim 6, wherein the third resonance frequency point and the fourth resonance frequency point are different.
8. Push-pull power amplification circuit as claimed in claim 1,
the first LC filter circuit comprises a first capacitor and a first inductor which are connected in series, one end of the first capacitor is coupled to the output end of the first power amplifying tube, the other end of the first capacitor is connected with the first end of the first inductor, and the second end of the first inductor is connected with a ground end;
the second LC filter circuit comprises a second capacitor and a second inductor which are connected in series, one end of the second capacitor is coupled to the output end of the second power amplifier tube, the other end of the second capacitor is connected with the first end of the second inductor, and the second end of the second inductor is connected with the grounding end.
9. A radio frequency front end module, comprising a substrate and a push-pull power amplifier chip disposed on the substrate, wherein the push-pull power amplifier chip is provided with a push-pull power amplifier circuit as claimed in any one of claims 1 to 8.
10. The rf front-end module of claim 9, further comprising a first converting balun disposed on the substrate, the first converting balun including a first input terminal and a second input terminal, the output terminal of the first power amplifying tube being connected to the first input terminal of the first converting balun by a first transmission line, and the output terminal of the second power amplifying tube being connected to the second input terminal of the first converting balun by a second transmission line.
11. The rf front-end module of claim 10, further comprising a feed power disposed on the substrate, the feed power coupled to the output of the first power amplifier tube through a first feed inductance, the feed power coupled to the output of the second power amplifier tube through a second feed inductance.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122404694.3U CN216252675U (en) | 2021-09-30 | 2021-09-30 | Push-pull power amplifying circuit and radio frequency front end module |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122404694.3U CN216252675U (en) | 2021-09-30 | 2021-09-30 | Push-pull power amplifying circuit and radio frequency front end module |
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| CN216252675U true CN216252675U (en) | 2022-04-08 |
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| CN202122404694.3U Active CN216252675U (en) | 2021-09-30 | 2021-09-30 | Push-pull power amplifying circuit and radio frequency front end module |
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