Push-pull power amplification circuit

Abstract

The application discloses a push-pull power amplifier circuit, which comprises a first power amplifier, a second power amplifier, an impedance adjustable unit and a first switching switch; a first input end of the impedance adjustable unit is connected with an output end of the first power amplifier, and a second input end of the impedance adjustable unit is connected with an output end of the second power amplifier; a first end of the first switching switch is connected with an input end of the first power amplifier, and a second end of the first switching switch is grounded; when the push-pull power amplifier circuit works in a high-power mode, the first switching switch is turned off, and the impedance adjustable unit forms a first impedance value; when the push-pull power amplifier circuit works in a low-power mode, the first switching switch is turned on, and the impedance adjustable unit forms a second impedance value, and the first impedance value is smaller than the second impedance value. The technical scheme can improve power-added efficiency and gain flatness of the push-pull power amplifier circuit under different power modes.

Description

Technical Field

[0001] This invention relates to the field of radio frequency technology, and in particular to a push-pull power amplifier circuit. Background Technology

[0002] Currently, push-pull power amplifiers are widely used in radio frequency front-ends because they can meet the requirements of higher frequencies and higher-order QAM modulation.

[0003] However, in order to achieve high bandwidth performance, existing push-pull power amplifiers suffer from low power-added efficiency (PAE) due to circuit structure limitations when switching power modes, which affects the overall performance of the push-pull power amplifier circuit. Summary of the Invention

[0004] This invention provides a push-pull power amplifier circuit to solve the problem of low power-added efficiency in existing push-pull power amplifiers.

[0005] A push-pull power amplifier circuit includes a first power amplifier, a second power amplifier, an impedance adjustable unit, and a first switching switch;

[0006] The first input terminal of the impedance-adjustable unit is connected to the output terminal of the first power amplifier and is configured to receive the first radio frequency amplified signal. The second input terminal of the impedance-adjustable unit is connected to the output terminal of the second power amplifier and is configured to receive the second radio frequency amplified signal. The output terminal of the impedance-adjustable unit is configured to output a radio frequency output signal.

[0007] The first terminal of the first switching switch is connected to the input terminal of the first power amplifier, and the second terminal of the first switching switch is grounded.

[0008] When the push-pull power amplifier circuit operates in high power mode, the first switching switch is off, and the impedance adjustable unit forms a first impedance value. When the push-pull power amplifier circuit operates in low power mode, the first switching switch is on, and the impedance adjustable unit forms a second impedance value, wherein the first impedance value is less than the second impedance value.

[0009] Furthermore, the impedance-adjustable unit includes an output conversion balun;

[0010] The first input terminal of the output conversion balun is connected to the output terminal of the first power amplifier, the second input terminal of the output conversion balun is connected to the output terminal of the second power amplifier, the first output terminal of the output conversion balun is configured to output a radio frequency output signal, and the second output terminal of the output conversion balun is grounded.

[0011] The output conversion balun includes a primary winding and a secondary winding;

[0012] When the push-pull power amplifier circuit operates in high power mode, the turns ratio of the primary winding and the secondary winding is a first turns ratio; when the push-pull power amplifier circuit operates in low power mode, the turns ratio of the primary winding and the secondary winding is a second turns ratio.

[0013] Wherein, the first turns ratio is less than the second turns ratio.

[0014] Furthermore, the impedance adjustable unit also includes a second switching switch, which is configured to make the impedance of the output conversion balun less in high power mode than in low power mode.

[0015] Furthermore, the second switching switch is connected in parallel with a portion of the primary coil segment of the primary winding. When the push-pull power amplifier circuit is in low-power mode, the second switching switch is off, and when the push-pull power amplifier circuit is in high-power mode, the second switching switch is on.

[0016] Furthermore, the second switching switch is connected in parallel with a portion of the secondary coil segment of the secondary winding.

[0017] When the push-pull power amplifier circuit is in low power mode, the second switching switch is turned on; when the push-pull power amplifier circuit is in high power mode, the second switching switch is turned off.

[0018] Furthermore, the first end of the second switching switch is connected to the center tap of the primary winding, and the second end of the second switching switch is connected to the first end of the primary winding; or, the first end of the second switching switch is connected to the center tap of the primary winding, and the second end of the second switching switch is connected to the second end of the primary winding.

[0019] Furthermore, the first end of the second switching switch is connected to the center tap of the secondary winding, and the second end of the second switching switch is connected to the first end of the secondary winding; or, the first end of the second switching switch is connected to the center tap of the secondary winding, and the second end of the second switching switch is connected to the second end of the secondary winding.

[0020] Furthermore, the first power amplifier is a BJT transistor, including a base, a collector, and an emitter. The base of the first power amplifier receives the first radio frequency input signal, the collector of the first power amplifier is coupled to the first input terminal of the impedance adjustable unit, and the emitter of the first power amplifier is grounded.

[0021] The second power amplifier is a BJT transistor, including a base, a collector, and an emitter. The base of the second power amplifier receives the second radio frequency input signal, the collector of the second power amplifier is coupled to the second input terminal of the impedance adjustable unit, and the emitter of the second power amplifier is grounded.

[0022] Furthermore, the push-pull power amplifier circuit includes a third switching switch, the first end of which is connected to the input terminal of the second power amplifier, and the second end of which is coupled to the ground terminal.

[0023] Furthermore, the push-pull power amplifier circuit also includes a first impedance matching unit and a second impedance matching unit.

[0024] The first terminal of the first impedance matching unit is connected to the first switching switch, and the second terminal of the first impedance matching unit is grounded.

[0025] The first end of the second impedance matching unit is connected to the second switching switch, and the second end of the second impedance matching unit is grounded.

[0026] The aforementioned push-pull power amplifier circuit includes a first power amplifier, a second power amplifier, an impedance-adjustable unit, and a first switching switch. The first input terminal of the impedance-adjustable unit is connected to the output terminal of the first power amplifier, and the second input terminal is connected to the output terminal of the second power amplifier. The first terminal of the first switching switch is connected to the input terminal of the first power amplifier, and the second terminal is grounded. When the push-pull power amplifier circuit operates in high-power mode, the first switching switch is open, and the impedance-adjustable unit generates a first impedance value. When the push-pull power amplifier circuit operates in low-power mode, the first switching switch is open, and the impedance-adjustable unit generates a second impedance value, wherein the first impedance value is less than the second impedance value. In this embodiment, when the push-pull power amplifier circuit needs to operate in different power modes, the switching state of the first switching switch is controlled to make the push-pull power amplifier circuit operate in high power mode or low power mode. The output impedance of the push-pull power amplifier circuit in the corresponding power mode is adjusted and matched by the impedance adjustable unit to meet the impedance matching in different power modes, thereby improving the power added efficiency (PAE) and gain flatness of the push-pull power amplifier circuit in different power modes. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a circuit diagram of a push-pull power amplifier circuit in one embodiment of the present invention;

[0029] Figure 2 This is another circuit diagram of a push-pull power amplifier circuit in one embodiment of the present invention;

[0030] Figure 3 This is another circuit diagram of a push-pull power amplifier circuit in one embodiment of the present invention;

[0031] Figure 4 This is another circuit diagram of a push-pull power amplifier circuit in one embodiment of the present invention;

[0032] Figure 5 This is another circuit diagram of a push-pull power amplifier circuit in one embodiment of the present invention.

[0033] In the diagram: 10, First power amplifier; 20, Second power amplifier; 30, Impedance adjustable unit; 31, Output conversion balun; 40, Input conversion balun; 50, First impedance matching unit; 60, Second impedance matching unit. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0036] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0037] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0039] To fully understand this invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0040] This embodiment provides a push-pull power amplifier circuit, such as Figure 1 As shown, the circuit includes a first power amplifier 10, a second power amplifier 20, an impedance adjustable unit 30, and a first switching switch S11. The first input terminal of the impedance adjustable unit 30 is connected to the output terminal of the first power amplifier 10 and is configured to receive a first radio frequency amplified signal. The second input terminal of the impedance adjustable unit 30 is connected to the output terminal of the second power amplifier 20 and is configured to receive a second radio frequency amplified signal. The output terminal of the impedance adjustable unit 30 is configured to output a radio frequency output signal. The first terminal of the first switching switch S11 is connected to the input terminal of the first power amplifier 10, and the second terminal of the first switching switch S11 is grounded. When the push-pull power amplifier circuit operates in high power mode, the first switching switch S11 is open, and the impedance adjustable unit 30 forms a first impedance value. When the push-pull power amplifier circuit operates in low power mode, the first switching switch S11 is open, and the impedance adjustable unit 30 forms a second impedance value, wherein the first impedance value is less than the second impedance value.

[0041] In one specific embodiment, such as Figure 2 As shown, the push-pull power amplifier circuit includes an input conversion balun 40, a first differential amplifier branch, and a second differential amplifier branch. The first input terminal of the input conversion balun 40 is connected to the signal input terminal of the push-pull power amplifier, the second input terminal of the input conversion balun 40 is grounded, the first output terminal of the input conversion balun 40 is connected to the input terminal of the first differential amplifier branch, and the second output terminal of the input conversion balun 40 is connected to the input terminal of the second differential amplifier branch. The input conversion balun 40 is configured to receive a radio frequency (RF) signal and convert it into a first RF input signal and a second RF input signal, that is, to convert an unbalanced RF signal into a balanced first RF input signal and a balanced second RF input signal. The first differential amplifier branch is configured to amplify the first RF input signal and output a first RF amplified signal. The second differential amplifier branch is configured to amplify the second RF input signal and output a second RF amplified signal.

[0042] In one specific embodiment, such as Figure 1 As shown, the first differential amplifier branch includes a first power amplifier 10, which includes at least one first power amplifier transistor M1, which can be an HBT transistor (e.g., a BJT transistor) or a field-effect transistor. The second differential amplifier branch includes a second power amplifier 20. The second power amplifier 20 includes at least one second power amplifier transistor M2, which can be an HBT transistor (e.g., a BJT transistor) or a field-effect transistor.

[0043] In one specific embodiment, such as Figure 1As shown, the first power amplifier 10 is a BJT transistor, including a base, a collector, and an emitter. The base of the first power amplifier 10 receives the first radio frequency input signal, the collector of the first power amplifier 10 is coupled to the first input terminal of the impedance adjustable unit 30, and the emitter of the first power amplifier 10 is grounded. The second power amplifier 20 is a BJT transistor, including a base, a collector, and an emitter. The base of the second power amplifier 20 receives the second radio frequency input signal, the collector of the second power amplifier 20 is coupled to the second input terminal of the impedance adjustable unit 30, and the emitter of the second power amplifier 20 is grounded.

[0044] Optionally, such as Figure 2 As shown, the first differential amplifier branch also includes a first capacitor C11. The first terminal of the first capacitor C11 is connected to the first output terminal of the input conversion balun 40, and the second terminal of the first capacitor C11 is connected to the second output terminal of the input conversion balun 40. The second differential amplifier branch also includes a second capacitor C21. The first terminal of the second capacitor C21 is connected to the second output terminal of the input conversion balun 40, and the second terminal of the second capacitor C21 is connected to the second output terminal of the input conversion balun 40. The first capacitor C11 and the second capacitor C21 are used for impedance matching of the input impedance of the push-pull power amplifier circuit, and their capacitance values ​​can be configured according to actual needs.

[0045] In one specific embodiment, the push-pull power amplifier circuit further includes an impedance-adjustable unit 30. The first input terminal of the impedance-adjustable unit 30 is connected to the output terminal of the first power amplifier 10 and configured to receive a first radio frequency (RF) amplified signal. The second input terminal of the impedance-adjustable unit 30 is connected to the output terminal of the second power amplifier 20 and configured to receive a second RF amplified signal. The output terminal of the impedance-adjustable unit 30 is configured to output an RF output signal. In this embodiment, the impedance-adjustable unit 30 can receive the first and second RF amplified signals output by the first amplifier, convert the balanced first and second RF amplified signals, output an RF output signal, and adjust the impedance value according to the operating mode of the push-pull power amplifier circuit to perform impedance matching of the output impedance of the push-pull power amplifier circuit. For example, when the push-pull power amplifier circuit operates in high-power mode, the impedance adjustable unit 30 forms a first impedance value, and when the push-pull power amplifier circuit operates in low-power mode, the impedance adjustable unit 30 forms a second impedance value. Since the push-pull power amplifier circuit requires a smaller output impedance when operating in high-power mode and a larger output impedance when operating in low-power mode, the first impedance value is smaller than the second impedance value to meet the impedance matching of the push-pull power amplifier circuit in different power modes, thereby improving the power-added efficiency (PAE) and gain flatness of the push-pull power amplifier circuit in different power modes.

[0046] In one specific embodiment, the push-pull power amplifier circuit further includes a first switching switch S11. The first terminal of the first switching switch S11 is connected to the input terminal of the first power amplifier 10, and the second terminal of the first switching switch S11 is grounded. In this embodiment, when the push-pull power amplifier circuit operates in high-power mode, the first switching switch S11 is open, and the first power amplifier 10 and the second power amplifier 20 operate simultaneously. The impedance adjustable unit 30 adjusts the impedance value to a first impedance value to perform impedance matching on the output impedance of the push-pull power amplifier circuit operating in high-power mode, thereby ensuring the power-added efficiency of the push-pull power amplifier circuit in high-power mode. When the push-pull power amplifier circuit operates in low-power mode, the first switching switch S11 is turned on, the first RF input signal is released to ground through the first switching switch S11, the second power amplifier 20 is activated, and the impedance adjustable unit 30 adjusts the impedance value to the second impedance value to perform impedance matching on the output impedance of the push-pull power amplifier circuit operating in low-power mode, so as to ensure the power-added efficiency of the push-pull power amplifier circuit in low-power mode, thereby improving the power-added efficiency (PAE) and gain flatness of the push-pull power amplifier circuit in different power modes.

[0047] It should be noted that since the first power amplifier 10 and the second power amplifier 20 are the same amplifier, the first terminal of the first switching switch S11 is connected to the input terminal of the second push-pull power amplifier circuit, and the second terminal of the first switching switch S11 is grounded. When the push-pull power amplifier circuit is operating in high power mode, the second switching switch S31 is open, and when the push-pull power amplifier circuit is operating in low power mode, the second switching switch S31 is open. This can also switch the power mode of the push-pull power amplifier circuit, thereby improving the power-added efficiency and gain flatness of the push-pull power amplifier circuit.

[0048] In this embodiment, the push-pull power amplifier circuit includes a first power amplifier 10, a second power amplifier 20, an impedance adjustable unit 30, and a first switching switch S11. The first input terminal of the impedance adjustable unit 30 is connected to the output terminal of the first power amplifier 10, and the second input terminal of the impedance adjustable unit 30 is connected to the output terminal of the second power amplifier 20. The first terminal of the first switching switch S11 is connected to the input terminal of the first power amplifier 10, and the second terminal of the first switching switch S11 is grounded. When the push-pull power amplifier circuit operates in high-power mode, the first switching switch S11 is open, and the impedance adjustable unit 30 forms a first impedance value. When the push-pull power amplifier circuit operates in low-power mode, the first switching switch S11 is closed, and the impedance adjustable unit 30 forms a second impedance value, wherein the first impedance value is less than the second impedance value. In this embodiment, by controlling the switching state of the first switching switch S11, the push-pull power amplifier circuit can operate in high power mode or low power mode. The output impedance of the push-pull power amplifier circuit in the corresponding power mode is adjusted and matched by the impedance adjustable unit 30 to meet the impedance matching in different power modes, thereby improving the power-added efficiency (PAE) and gain flatness of the push-pull power amplifier circuit in different power modes.

[0049] In one embodiment, such as Figure 2 As shown, the impedance-adjustable unit 30 includes an output conversion balun 31; the first input terminal of the output conversion balun 31 is connected to the output terminal of the first power amplifier 10, the second input terminal of the output conversion balun 31 is connected to the output terminal of the second power amplifier 20, the first output terminal of the output conversion balun 31 is configured to output a radio frequency output signal, and the second output terminal of the output conversion balun 31 is grounded; the output conversion balun 31 includes a primary winding and a secondary winding; when the push-pull power amplifier circuit operates in high-power mode, the turns ratio of the primary winding and the secondary winding is a first turns ratio, and when the push-pull power amplifier circuit operates in low-power mode, the turns ratio of the primary winding and the secondary winding is a second turns ratio; wherein, the first turns ratio is less than the second turns ratio.

[0050] In one specific embodiment, the impedance adjustable unit 30 includes an output conversion balun 31. The first input terminal of the output conversion balun 31 is connected to the output terminal of the first power amplifier 10 and is configured to receive a first radio frequency amplified signal. The second input terminal of the output conversion balun 31 is connected to the output terminal of the second power amplifier 20 and is configured to receive a second radio frequency amplified signal. The first output terminal of the output conversion balun 31 is configured to output a radio frequency output signal, and the second output terminal of the output conversion balun 31 is grounded. The output conversion balun 31 is configured to convert the first radio frequency amplified signal and the second radio frequency amplified signal and output a radio frequency amplified signal.

[0051] In one specific embodiment, the output conversion balun 31 includes a primary winding and a secondary winding. When the push-pull power amplifier circuit operates in high-power mode, the turns ratio of the primary winding to the secondary winding is a first turns ratio. When the push-pull power amplifier circuit operates in low-power mode, the turns ratio of the primary winding to the secondary winding is a second turns ratio; wherein, the first turns ratio is less than the second turns ratio. In this embodiment, when the push-pull power amplifier circuit operates in high-power mode, in order to meet the impedance matching requirements of the push-pull power amplifier circuit in high-power mode, the output impedance value of the push-pull power amplifier circuit should be relatively small, and the impedance value of the output conversion balun 31 is adjusted to the first impedance value, which is relatively small. When the push-pull power amplifier circuit operates in low-power mode, in order to meet the impedance matching requirements of the push-pull power amplifier circuit in low-power mode, the output impedance value of the output conversion balun 31 should be relatively large, that is, the impedance value of the impedance adjustable unit 30 is adjusted to the second impedance value, which is relatively large. Since the impedance of the output switching balun 31 is positively correlated with the turns ratio of the primary and secondary windings—that is, the larger the impedance of the output switching balun 31, the larger the turns ratio of the primary and secondary windings—the following applies to the push-pull power amplifier circuit: When operating in high-power mode, the turns ratio of the primary and secondary windings is a first turns ratio, for example, 1:4. When operating in low-power mode, the turns ratio is a second turns ratio, for example, 1:2. The first turns ratio is smaller than the second turns ratio to ensure impedance matching in both high-power and low-power modes, thereby improving the power-added efficiency of the push-pull power amplifier circuit.

[0052] In one specific embodiment, the push-pull power amplifier circuit further includes a power supply terminal VDD, which is connected to the center tap of the primary winding and is used to supply power to the first power amplifier 10 and the second power amplifier 20.

[0053] In one embodiment, such as Figure 2 As shown, the impedance adjustable unit 30 also includes a second switching switch S31, which is configured to make the impedance of the output switching balun 31 in high power mode less than that in low power mode.

[0054] In one specific embodiment, the impedance adjustable unit 30 further includes a second switching switch S31. In this embodiment, the second switching switch S31 is used to make the impedance of the output conversion balun 31 in high power mode less than that in low power mode, so as to perform impedance matching on the output impedance of the push-pull power amplifier circuit and improve the power-added efficiency of the push-pull power amplifier circuit in high power mode or low power mode.

[0055] In one embodiment, such as Figure 3As shown, the second switching switch S31 is connected in parallel with part of the primary coil segment of the primary winding. When the push-pull power amplifier circuit is in low power mode, the second switching switch S31 is off, and when the push-pull power amplifier circuit is in high power mode, the second switching switch S31 is on.

[0056] In one specific embodiment, the second switching switch S31 is connected in parallel with a portion of the primary coil of the primary winding. When the push-pull power amplifier circuit is in low-power mode, the second switching switch S31 is turned off to increase the number of turns in the primary winding. When the push-pull power amplifier circuit is in high-power mode, the second switching switch S31 is turned on to decrease the number of turns in the primary winding. In this embodiment, since the second switching switch S31 is connected in parallel with a portion of the primary coil of the primary winding, when the push-pull power amplifier circuit is in low-power mode, the second switching switch S31 is turned off to increase the number of turns in the primary winding. With the number of turns in the secondary winding remaining unchanged, the turns ratio of the primary winding to the secondary winding can be increased, thereby increasing the impedance value of the impedance adjustable unit 30 and improving the power-added efficiency of the push-pull power amplifier circuit in low-power mode. When the push-pull power amplifier circuit is in high-power mode, the second switching switch S31 is turned on to reduce the number of turns of the primary winding, thereby reducing the impedance value of the impedance adjustable unit 30 and improving the power-added efficiency of the push-pull power amplifier circuit in high-power mode. When the push-pull power amplifier circuit is in low-power mode, the second switching switch S31 is turned off to increase the number of turns of the primary winding, thereby increasing the impedance value of the impedance adjustable unit 30 and improving the power-added efficiency of the push-pull power amplifier circuit in low-power mode.

[0057] In one embodiment, such as Figure 2 As shown, the second switching switch S31 is connected in parallel with part of the secondary coil segment of the secondary winding. When the push-pull power amplifier circuit is in low power mode, the second switching switch S31 is turned on, and when the push-pull power amplifier circuit is in high power mode, the second switching switch S31 is turned off.

[0058] In one specific embodiment, the second switching switch S31 is connected in parallel with a portion of the secondary coil segment of the secondary winding. When the push-pull power amplifier circuit is in low-power mode, the second switching switch S31 is turned on to reduce the number of turns in the secondary winding. When the push-pull power amplifier circuit is in high-power mode, the second switching switch S31 is turned off to increase the number of turns in the secondary winding. In this embodiment, since the second switching switch S31 is connected in parallel with a portion of the secondary coil segment of the secondary winding, when the push-pull power amplifier circuit is in low-power mode, the second switching switch S31 is turned on to reduce the number of turns in the secondary winding, thereby increasing the impedance value of the impedance-adjustable unit 30, and thus improving the power-added efficiency of the push-pull power amplifier circuit in low-power mode. When the push-pull power amplifier circuit is in high-power mode, the second switching switch S31 is turned off to increase the number of turns in the secondary winding, thereby reducing the impedance value of the impedance-adjustable unit 30, and thus improving the power-added efficiency of the push-pull power amplifier circuit in high-power mode.

[0059] In one embodiment, such as Figure 3 As shown, the first end of the second switching switch S31 is connected to the primary winding, and the second end of the second switching switch S31 is connected to the first end of the primary winding; or, the first end of the second switching switch S31 is connected to the secondary winding, and the second end of the second switching switch S31 is connected to the second end of the primary winding.

[0060] In one specific embodiment, the first end of the second switching switch S31 is connected to a portion of the primary coil segment of the primary winding, and the second end of the second switching switch S31 is connected to the first end of the primary winding; alternatively, the first end of the second switching switch S31 is connected to the secondary winding, and the second end of the second switching switch S31 is connected to the second end of the primary winding. In this embodiment, the position of the first end of the second switching switch S31 on the portion of the primary coil segment of the primary winding can be adjusted according to actual needs to determine the number of turns connected to the primary winding in the push-pull power amplifier circuit after the second switching switch S31 is turned on; or, the position of the first end of the second switching switch S31 on the portion of the secondary coil segment of the secondary winding can be adjusted according to actual needs to determine the number of turns connected to the secondary winding in the push-pull power amplifier circuit after the second switching switch S31 is turned on.

[0061] In this embodiment, by connecting the first end of the second switching switch S31 to the primary winding and connecting the second end of the second switching switch S31 to the first end of the primary winding, when the push-pull power amplifier circuit is in high-power mode and the second switching switch S31 is off, the turns ratio of the primary winding to the secondary winding is reduced, the impedance value of the impedance adjustable unit 30 is reduced, and the power-added efficiency of the push-pull power amplifier circuit in high-power mode is improved; when the push-pull power amplifier circuit is in low-power mode and the second switching switch S31 is on, the turns ratio of the primary winding to the secondary winding is increased, the impedance value of the impedance adjustable unit 30 is increased, and the power-added efficiency of the push-pull power amplifier circuit in high-power mode is improved.

[0062] Alternatively, the first terminal of the second switching switch S31 can be connected to the secondary winding, and the second terminal of the second switching switch S31 can be connected to the second terminal of the secondary winding. When the push-pull power amplifier circuit is in low-power mode and the second switching switch S31 is open, the turns ratio of the primary winding to the secondary winding is increased, the impedance value of the impedance adjustable unit 30 is increased, and the power-added efficiency of the push-pull power amplifier circuit in low-power mode is improved. When the push-pull power amplifier circuit is in high-power mode and the second switching switch S31 is on, the turns ratio of the primary winding to the secondary winding is decreased, the impedance value of the impedance adjustable unit 30 is decreased, and the power-added efficiency of the push-pull power amplifier circuit in high-power mode is improved.

[0063] In one embodiment, such as Figure 2 As shown, the first end of the second switching switch S31 is connected to the secondary winding, and the second end of the second switching switch S31 is connected to the first end of the secondary winding; or, the first end of the second switching switch S31 is connected to the secondary winding, and the second end of the second switching switch S31 is connected to the second end of the secondary winding.

[0064] In one specific embodiment, the first end of the second switching switch S31 is connected to the secondary winding, and the second end of the second switching switch S31 is connected to the first end of the secondary winding; or, the first end of the second switching switch S31 is connected to the secondary winding, and the second end of the second switching switch S31 is connected to the second end of the secondary winding. In this embodiment, the turns ratio between the primary winding and the secondary winding in the push-pull power amplifier circuit after the second switching switch S31 is turned on can be determined according to the actual requirements of the position of the first end of the second switching switch S31 connected to a portion of the secondary coil segment of the secondary winding.

[0065] In this embodiment, by connecting the first terminal of the second switching switch S31 to the secondary winding and connecting the second terminal of the second switching switch S31 to the first terminal of the secondary winding, or by connecting the first terminal of the second switching switch S31 to the secondary winding and connecting the second terminal of the second switching switch S31 to the second terminal of the secondary winding, both can increase the turns ratio of the primary winding to the secondary winding when the push-pull power amplifier circuit is in low-power mode and the second switching switch S31 is turned on, thereby increasing the impedance value of the impedance adjustable unit 30 and improving the power-added efficiency of the push-pull power amplifier circuit in low-power mode; and decrease the turns ratio of the primary winding to the secondary winding when the push-pull power amplifier circuit is in high-power mode and the second switching switch S31 is turned off, thereby decreasing the impedance value of the impedance adjustable unit 30 and improving the power-added efficiency of the push-pull power amplifier circuit in high-power mode.

[0066] In one embodiment, such as Figure 2 or Figure 3 As shown, the first end of the second switching switch S31 is connected to the center tap of the primary winding or the secondary winding.

[0067] In one specific embodiment, the first end of the second switching switch S31 is connected to the center tap of the primary winding, and the second end of the second switching switch S31 is connected to the first or second end of the primary winding.

[0068] In one specific embodiment, the first end of the second switching switch S31 is connected to the center tap of the secondary winding, and the second end of the second switching switch S31 is connected to the first end or the second end of the secondary winding.

[0069] For example, the first end of the second switching switch S31 is connected to the center tap of the secondary winding, and the second end of the second switching switch S31 is connected to the first end of the secondary winding. When the second switching switch S31 is off, the turns ratio of the primary winding to the secondary winding is 4:2. Since the first end of the second switching switch S31 is connected to the center tap of the secondary winding, and the second end of the second switching switch S31 is connected to the first end of the secondary winding, when the second switching switch S31 is on, the turns ratio of the primary winding to the secondary winding is 4:1, and the turns ratio of the primary winding to the secondary winding increases.

[0070] In this embodiment, by connecting the first end of the second switching switch S31 to the center tap of the primary winding or the secondary winding, it is convenient to adjust the turns ratio of the primary winding and the secondary winding by switching the state of the second switching switch S31.

[0071] In one embodiment, such as Figure 4As shown, the push-pull power amplifier circuit includes a third switching switch S21. The first terminal of the third switching switch S21 is connected to the input terminal of the second power amplifier 20, and the second terminal of the third switching switch S21 is grounded. The first terminal of the first switching switch S11 is connected to the input terminal of the first power amplifier 10, and the second terminal of the first switching switch S11 is grounded. When the push-pull power amplifier circuit is in low power mode, either the first switching switch S11 or the third switching switch S21 is turned on, and the second switching switch S31 is turned on. When the push-pull power amplifier circuit is in high power mode, the first switching switch S11, the second switching switch S31, and the third switching switch S21 are turned off.

[0072] In one specific embodiment, the first terminal of the third switching switch S21 is connected to the input terminal of the second power amplifier 20, and the second terminal of the third switching switch S21 is grounded. The input terminal of the first power amplifier 10 is connected to the first switching switch S11, and the second terminal of the first switching switch S11 is grounded. In this embodiment, when the push-pull power amplifier circuit is in low-power mode, either the first switching switch S11 or the third switching switch S21 is turned on, and the second switching switch S31 is turned on. When the push-pull power amplifier circuit is in high-power mode, the first switching switch S11, the second switching switch S31, and the third switching switch S21 are turned off, thereby improving the power-added efficiency and gain flatness of the push-pull power amplifier circuit in different power modes.

[0073] In one embodiment, such as Figure 5 As shown, the push-pull power amplifier circuit also includes a first impedance matching unit 50 and a second impedance matching unit 60; the first end of the first impedance matching unit 50 is connected to the first switching switch S11, and the second end of the first impedance matching unit 50 is grounded; the first end of the second impedance matching unit 60 is connected to the second switching switch S31, and the second end of the second impedance matching unit 60 is grounded.

[0074] In one specific embodiment, the first terminal of the first impedance matching unit 50 is connected to the first switching switch S11, and the second terminal of the first impedance matching unit 50 is grounded. The first impedance matching unit 50C participates in the impedance matching of the push-pull power amplifier circuit to achieve more flexible adjustment of the impedance of the push-pull power amplifier circuit. Optionally, the first impedance matching unit 50 includes a first inductor and a third capacitor (not shown in the figure), which can be connected in parallel or in series.

[0075] Optionally, the push-pull power amplifier circuit further includes a second impedance matching unit 60 (not shown in the figure). The first terminal of the second impedance matching unit 60 is connected to the third switching switch S21, and the second terminal of the second impedance matching unit 60 is grounded. The second impedance matching unit 60 participates in the impedance matching of the push-pull power amplifier circuit to achieve more flexible adjustment of the impedance of the push-pull power amplifier circuit. Optionally, the second impedance matching unit 60 includes a third inductor and a fifth capacitor (not shown in the figure), which can be connected in parallel or in series.

[0076] In one specific embodiment, the push-pull power amplifier circuit further includes a third impedance matching unit. The first terminal of the third impedance matching unit is connected to the first output terminal of the output conversion balun 31, and the second terminal of the third impedance matching unit is configured to output a radio frequency output signal to adjust the output impedance of the push-pull power amplifier circuit to achieve output impedance matching. Optionally, the third impedance matching unit includes a second inductor and a fourth capacitor, which can be connected in parallel or in series (not shown in the figure).

[0077] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A push-pull power amplifier circuit, characterized in that, It includes a first power amplifier, a second power amplifier, an impedance adjustable unit, and a first switching switch; The first input terminal of the impedance-adjustable unit is connected to the output terminal of the first power amplifier and is configured to receive the first radio frequency amplified signal. The second input terminal of the impedance-adjustable unit is connected to the output terminal of the second power amplifier and is configured to receive the second radio frequency amplified signal. The output terminal of the impedance-adjustable unit is configured to output a radio frequency output signal. The first terminal of the first switching switch is connected to the input terminal of the first power amplifier, and the second terminal of the first switching switch is grounded. When the push-pull power amplifier circuit operates in high power mode, the first switching switch is off, and the impedance adjustable unit forms a first impedance value. When the push-pull power amplifier circuit operates in low power mode, the first switching switch is on, and the impedance adjustable unit forms a second impedance value, wherein the first impedance value is less than the second impedance value. The impedance-adjustable unit includes an output conversion balun and a second switching switch; The first input terminal of the output conversion balun is connected to the output terminal of the first power amplifier, the second input terminal of the output conversion balun is connected to the output terminal of the second power amplifier, the first output terminal of the output conversion balun is configured to output a radio frequency output signal, and the second output terminal of the output conversion balun is grounded; the output conversion balun includes a primary winding and a secondary winding; The second switching switch is connected in parallel with a portion of the primary coil segment of the primary winding, or the second switching switch is connected in parallel with a portion of the secondary coil segment of the secondary winding.

2. The push-pull power amplifier circuit as described in claim 1, characterized in that, When the push-pull power amplifier circuit operates in high power mode, the turns ratio of the primary winding and the secondary winding is a first turns ratio; when the push-pull power amplifier circuit operates in low power mode, the turns ratio of the primary winding and the secondary winding is a second turns ratio. Wherein, the first turns ratio is less than the second turns ratio.

3. The push-pull power amplifier circuit as described in claim 1, characterized in that, The second switching switch is configured such that the impedance of the output conversion balun in high power mode is less than that in low power mode.

4. The push-pull power amplifier circuit as described in claim 1, characterized in that, The second switching switch is connected in parallel with a portion of the primary coil segment of the primary winding. When the push-pull power amplifier circuit is in low power mode, the second switching switch is off, and when the push-pull power amplifier circuit is in high power mode, the second switching switch is on.

5. The push-pull power amplifier circuit as described in claim 1, characterized in that, The second switching switch is connected in parallel with a portion of the secondary coil segment of the secondary winding. When the push-pull power amplifier circuit is in low power mode, the second switching switch is turned on; when the push-pull power amplifier circuit is in high power mode, the second switching switch is turned off.

6. The push-pull power amplifier circuit as described in claim 2, characterized in that, The first end of the second switching switch is connected to the center tap of the primary winding, and the second end of the second switching switch is connected to the first end of the primary winding; or, the first end of the second switching switch is connected to the center tap of the primary winding, and the second end of the second switching switch is connected to the second end of the primary winding.

7. The push-pull power amplifier circuit as described in claim 3, characterized in that, The first end of the second switching switch is connected to the center tap of the secondary winding, and the second end of the second switching switch is connected to the first end of the secondary winding; or, the first end of the second switching switch is connected to the center tap of the secondary winding, and the second end of the second switching switch is connected to the second end of the secondary winding.

8. The push-pull power amplifier circuit as described in claim 1, characterized in that, The first power amplifier is a BJT transistor, including a base, a collector, and an emitter. The base of the first power amplifier receives the first radio frequency input signal, the collector of the first power amplifier is coupled to the first input terminal of the impedance adjustable unit, and the emitter of the first power amplifier is grounded. The second power amplifier is a BJT transistor, including a base, a collector, and an emitter. The base of the second power amplifier receives the second radio frequency input signal, the collector of the second power amplifier is coupled to the second input terminal of the impedance adjustable unit, and the emitter of the second power amplifier is grounded.

9. The push-pull power amplifier circuit as described in claim 1, characterized in that, The push-pull power amplifier circuit includes a third switching switch, the first end of which is connected to the input terminal of the second power amplifier, and the second end of which is coupled to the ground terminal.

10. The push-pull power amplifier circuit as described in claim 1, characterized in that, The push-pull power amplifier circuit also includes a first impedance matching unit and a second impedance matching unit. The first terminal of the first impedance matching unit is connected to the first switching switch, and the second terminal of the first impedance matching unit is grounded. The first end of the second impedance matching unit is connected to the second switching switch, and the second end of the second impedance matching unit is grounded.

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