Radio frequency power amplifier, radio frequency front-end module and electronic equipment

Abstract

The embodiment of the invention provides a radio frequency power amplifier, a radio frequency front-end module and electronic equipment. The radio frequency power amplifier comprises a differential power amplification circuit and a transformer, the transformer comprises a first coil and a second coil, the second coil and the first coil are mutually coupled, a first output end of the differential amplification circuit is connected with a first end of the first coil, a second output end of the differential amplification circuit is connected with a second end of the first coil, and a first end of the second coil is connected to a signal output end; the second end of the second coil is connected to the ground; wherein the first coil at least comprises a first sub-coil and a second sub-coil, and the first sub-coil and the second sub-coil are connected in parallel; the second coil at least comprises a third sub-coil and a fourth sub-coil, and the third sub-coil and the fourth sub-coil are connected in series. According to the radio frequency power amplifier, the transformer can realize a higher impedance conversion ratio, so that the power additional efficiency of the radio frequency power amplifier is improved, the power of a radio frequency signal is improved, and the radio frequency signal has higher power and coverage distance.

Description

Technical Field

[0001] The present application relates to the field of radio frequency technology, and in particular to a radio frequency power amplifier, a radio frequency front-end module and an electronic device. Background Art

[0002] With the development of mobile Internet, more and more devices are connected to mobile networks, new services and applications are emerging, and the surge in mobile data traffic will bring severe challenges to the network. RF front-end modules play a vital role in the field of mobile communications. In mobile phones, tablets and other mobile devices, RF front-end modules are responsible for receiving and sending wireless signals to achieve communication with base stations. The carrier coverage distance of high-frequency bands is short, and the signal attenuation is large during transmission, which is very easy to be blocked. The insertion loss of RF front-end modules in related technologies is high, which affects the performance of RF front-end modules in high-frequency bands. Summary of the invention

[0003] The present application provides a radio frequency power amplifier, a radio frequency front-end module and an electronic device, which can improve the power added efficiency of the radio frequency power amplifier.

[0004] In a first aspect, an embodiment of the present application provides a radio frequency power amplifier, the radio frequency power amplifier comprising:

[0005] A differential power amplifier circuit, wherein the input end of the differential power amplifier circuit is used to input a radio frequency signal, the differential power amplifier circuit is used to amplify the radio frequency signal, and the first output end and the second output end of the differential power amplifier circuit are used to output the amplified radio frequency signal;

[0006] A transformer, the transformer comprising a first coil and a second coil, the second coil and the first coil are coupled to each other, the first output end of the differential amplifier circuit is connected to the first end of the first coil, the second output end of the differential amplifier circuit is connected to the second end of the first coil, the first end of the second coil is connected to the signal output end, and the second end of the second coil is connected to ground;

[0007] Among them, the first coil at least includes a first sub-coil and a second sub-coil, the first sub-coil is formed in a first metal layer, the second sub-coil is formed in a second metal layer, and the first sub-coil and the second sub-coil are connected in parallel; the second coil at least includes a third sub-coil and a fourth sub-coil, the third sub-coil and the fourth sub-coil are formed in a metal layer between the first metal layer and the second metal layer, and a projection of the second coil on the first metal layer at least partially overlaps with the first sub-coil, a projection of the second coil on the second metal layer at least partially overlaps with the second sub-coil, and the third sub-coil and the fourth sub-coil are connected in series.

[0008] In a second aspect, an embodiment of the present application provides a radio frequency power amplifier, the radio frequency power amplifier comprising:

[0009] A power amplifier circuit, wherein the input end of the power amplifier circuit is used to input a radio frequency signal, the power amplifier circuit is used to amplify the radio frequency signal, and the output end of the power amplifier circuit is used to output the amplified radio frequency signal;

[0010] A transformer, the transformer comprising a first coil and a second coil, the second coil and the first coil are coupled to each other, the output end of the power amplifier circuit is connected to the first coil, and the second coil is used to output the radio frequency signal after impedance transformation;

[0011] Among them, the first coil at least includes a first sub-coil and a second sub-coil, the first sub-coil is formed in a first metal layer, the second sub-coil is formed in a second metal layer, and the first sub-coil and the second sub-coil are connected in parallel; the second coil at least includes a third sub-coil and a fourth sub-coil, the third sub-coil and the fourth sub-coil are formed in a metal layer between the first metal layer and the second metal layer, and a projection of the second coil on the first metal layer at least partially overlaps with the first sub-coil, a projection of the second coil on the second metal layer at least partially overlaps with the second sub-coil, and the third sub-coil and the fourth sub-coil are connected in series.

[0012] In a third aspect, an embodiment of the present application provides a radio frequency front-end module, wherein the radio frequency front-end module includes the aforementioned radio frequency power amplifier.

[0013] In a fourth aspect, an embodiment of the present application provides an electronic device, which includes the aforementioned RF power amplifier or RF front-end module.

[0014] The RF power amplifier, RF front-end module and electronic device provided in the embodiments of the present application, the RF power amplifier includes a differential power amplifier circuit and a transformer; the input end of the differential power amplifier circuit is used to input a RF signal, the differential power amplifier circuit is used to amplify the RF signal, and the first output end and the second output end of the differential power amplifier circuit are used to output the amplified RF signal; the transformer includes a first coil and a second coil, the second coil is coupled to the first coil, the first output end of the differential amplifier circuit is connected to the first end of the first coil, the second output end of the differential amplifier circuit is connected to the second end of the first coil, the first end of the second coil is connected to the signal output end, and the second end of the second coil is connected to the ground; wherein the first coil includes at least a first sub-coil and a second sub-coil, the first sub-coil is formed on the first metal layer, the second sub-coil is formed on the second metal layer, and the first sub-coil and the second sub-coil are connected in parallel; the second coil includes at least a third sub-coil and a fourth sub-coil, the third sub-coil and the fourth sub-coil are formed on the metal layer between the first metal layer and the second metal layer, and the projection of the second coil on the first metal layer at least partially overlaps with the first sub-coil, the projection of the second coil on the second metal layer at least partially overlaps with the second sub-coil, and the third sub-coil and the fourth sub-coil are connected in series. The first sub-coil and the second sub-coil are connected in parallel to reduce the inductance of the first coil, and the third sub-coil and the fourth sub-coil are connected in series to increase the inductance of the second coil, so that the transformer can achieve a higher impedance conversion ratio, thereby improving the power added efficiency of the RF power amplifier to increase the power of the RF signal, thereby making the RF signal have higher power and coverage distance.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and cannot limit the disclosure of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is a schematic diagram of a radio frequency power amplifier provided in an embodiment of the present application;

[0018] Figure 2a to Figure 2c is a schematic diagram of the structure of a transformer in some embodiments of the present application;

[0019] Figure 3 is a schematic diagram of a radio frequency power amplifier in some embodiments of the present application;

[0020] Figures 4a to 4dis a schematic diagram of the structure of a transformer in some embodiments of the present application;

[0021] Figure 5 is a schematic diagram of a radio frequency power amplifier in some embodiments of the present application;

[0022] Figure 6 is a schematic block diagram of a radio frequency power amplifier provided in another embodiment of the present application;

[0023] Figure 7 is a schematic diagram of a radio frequency power amplifier in some embodiments of the present application;

[0024] Figure 8 is a schematic block diagram of a radio frequency front-end module provided in an embodiment of the present application;

[0025] Fig. 9 is a schematic block diagram of a radio frequency front-end module in one embodiment of the present application;

[0026] Fig.10 It is a schematic block diagram of an electronic device provided in an embodiment of the present application.

[0027] Description of reference numerals:

[0028] 10a, differential power amplifier circuit; 20, transformer; 210, first coil; 211, first sub-coil; 212, second sub-coil; 220, second coil; 221, third sub-coil; 222, fourth sub-coil; 230, first capacitor; 240, grounding structure; 241, metal plate; 242, metal through hole; Sa, first metal layer; Sb, second metal layer; Sc, third metal layer; Sd, fourth metal layer; T1, first metal body; T2, second metal body; T3, third metal body; L1, first bonding wire; L2, second bonding wire; C2, second capacitor; C3, third capacitor; 10, power amplifier circuit; 10b, single-ended power amplifier circuit. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] It should be understood that the present application can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0031] In order to thoroughly understand the present application, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0032] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0033] See also Figure 1 , Figure 1 It is a schematic block diagram of a radio frequency power amplifier of a power amplifier provided in an embodiment of the present application.

[0034] like Figure 1 As shown, the radio frequency power amplifier includes: a differential power amplifier circuit 10a and a transformer 20.

[0035] The input end of the differential power amplifier circuit 10a is used to input a radio frequency signal, the differential power amplifier circuit 10a is used to amplify the radio frequency signal, and the first output end and the second output end of the differential power amplifier circuit 10a are used to output the amplified radio frequency signal.

[0036] The transformer 20 includes a first coil 210 and a second coil 220, the second coil 220 is coupled to the first coil 210, the first output end of the differential amplifier circuit is connected to the first end of the first coil 210, the second output end of the differential amplifier circuit is connected to the second end of the first coil 210, the first end of the second coil 220 is connected to the signal output end, and the second end of the second coil 220 is connected to the ground.

[0037] Please combine Figure 1 See also Figure 2a to Figure 2c The first coil 210 at least includes a first sub-coil 211 and a second sub-coil 212. The first sub-coil 211 is formed on the first metal layer Sa, and the second sub-coil 212 is formed on the second metal layer Sb. The first sub-coil 211 and the second sub-coil 212 are connected in parallel.

[0038] By connecting the first sub-coil 211 and the second sub-coil 212 in the first coil 210 in parallel, the inductance of the first coil 210 is made smaller than the inductance of the first sub-coil 211 and smaller than the inductance of the second sub-coil 212, so that the first coil 210 with smaller inductance can be obtained.

[0039] There is also at least one metal layer between the first metal layer Sa and the second metal layer Sb. It can be understood that "first" and "second" are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part, rather than to limit the arrangement order.

[0040] In some embodiments, the transformer 20 is disposed on a substrate, and the first metal layer Sa, the second metal layer Sb, and the metal layer between the first metal layer Sa and the second metal layer Sb are metal layers on the substrate. The first metal layer Sa may be a metal layer on the top of the substrate, and may not be limited to being a metal layer on the top of the substrate. For example, the first metal layer Sa may be the second metal layer or the third metal layer on the substrate.

[0041] In other embodiments, the transformer 20 is disposed on an integrated passive device chip (IPD chip). Compared with arranging the transformer 20 on a substrate, integrating the transformer 20 in an integrated passive device chip (IPD chip) and arranging the integrated passive device chip (IPD chip) on a substrate can reduce the occupied area on the substrate, which is conducive to realizing a compact layout and miniaturized design of the RF power amplifier. For ease of explanation, the embodiments of the present application are mainly described by taking the transformer 20 being disposed on a substrate as an example.

[0042] Among them, the second coil 220 includes at least a third sub-coil 221 and a fourth sub-coil 222, the third sub-coil 221 and the fourth sub-coil 222 are formed in the metal layer between the first metal layer Sa and the second metal layer Sb, and the projection of the second coil 220 on the first metal layer Sa at least partially overlaps with the first sub-coil 211, the projection of the second coil 220 on the second metal layer Sb at least partially overlaps with the second sub-coil 212, and the third sub-coil 221 and the fourth sub-coil 222 are connected in series.

[0043] By connecting the third sub-coil 221 and the fourth sub-coil 222 in the second coil 220 in series, the inductance of the second coil 220 is made greater than the inductance of the third sub-coil 221 and greater than the inductance of the fourth sub-coil 222, so that a second coil 220 with a larger inductance can be obtained.

[0044] The first sub-coil 211 and the second sub-coil 212 are connected in parallel to reduce the inductance of the first coil 210, and the third sub-coil 221 and the fourth sub-coil 222 are connected in series to increase the inductance of the second coil 220, so that the transformer 20 can achieve a higher impedance conversion ratio. Exemplarily, the impedance conversion ratio of the first coil 210 and the second coil 220 is greater than or equal to 1:5 and less than or equal to 1:3. For example, the transformer 20 can convert the lower impedance of the output end of the differential power amplifier circuit 10a, such as the impedance in the range of [4 ohms, 60 ohms] into an impedance of 50 ohms. For example: 17 ohms, 15 ohms, 12.5 ohms, and 10 ohms are converted into 50 ohms.

[0045] In some embodiments, the turns ratio of the first coil 210 and the second coil 220 is greater than or equal to 1:4 and less than or equal to 1:1. Preferably, the turns ratio of the first coil 210 and the second coil 220 is greater than or equal to 1:4 and less than or equal to 1:2.5; further, the turns ratio of the first coil 210 and the second coil 220 is greater than or equal to 1:4 and less than or equal to 1:3.5.

[0046] In some embodiments, the operating frequency of the power amplifier circuit 10 and the transformer 20 is greater than or equal to 3.3 GHz and less than or equal to 5 GHz. Preferably, the operating frequency is greater than or equal to 4.04 GHz and less than or equal to 5 GHz. The transformer 20 can achieve a higher impedance conversion ratio, has a smaller parasitic impedance and a more compact structure, and can be better applied to higher frequencies and wider frequency bands.

[0047] In some embodiments, the supply voltage of the RF power amplifier is greater than or equal to 3V and less than or equal to 4V. Exemplarily, the operating frequency of the power amplifier circuit 10 and the transformer 20 is greater than or equal to 3.3GHz and less than or equal to 5GHz; and the supply voltage of the RF power amplifier is greater than or equal to 3V and less than or equal to 4V. Preferably, the supply voltage of the RF power amplifier is greater than or equal to 3.4V and less than or equal to 3.8V.

[0048] The transformer 20 with a higher turns ratio and a higher impedance conversion ratio can more significantly increase the power of the RF signal output by the differential power amplifier circuit 10a, and can still ensure that the RF power amplifier has lower losses and higher power added efficiency when the power supply voltage of the RF power amplifier is low, thereby making the RF signal output by the RF power amplifier have higher power and coverage distance, and reducing signal attenuation during RF signal transmission.

[0049] like Figure 2a to Figure 2cAs shown, the third sub-coil 221 and the fourth sub-coil 222 are formed in a metal layer between the first metal layer Sa where the first sub-coil 211 is located and the second metal layer Sb where the second sub-coil 212 is located, and the projection of the second coil 220 on the first metal layer Sa at least partially overlaps with the first sub-coil 211, and the projection of the second coil 220 on the second metal layer Sb at least partially overlaps with the second sub-coil 212, so that the second coil 220 can generate strong electromagnetic induction with the first sub-coil 211, and can also generate strong electromagnetic induction with the second sub-coil 212, that is, the second coil 220 and the first coil 210 can have a larger area for electromagnetic induction, thereby having a larger coupling coefficient.

[0050] In some embodiments, Figure 2a to Figure 2c As shown, the projection of the second sub-coil 212 on the first metal layer Sa at least partially overlaps with the first sub-coil 211. For example, the position of the second sub-coil 212 on the second metal layer Sb is the same as the position of the first sub-coil 211 on the first metal layer, making the structure of the transformer 20 more compact.

[0051] Exemplarily, the routing width of the first sub-coil 211 is greater than or equal to the sum of the routing widths of the third sub-coil 221 and the fourth sub-coil 222; and / or the routing width of the second sub-coil 212 is greater than or equal to the sum of the routing widths of the third sub-coil 221 and the fourth sub-coil 222. This allows the projection of the second coil 220 on the first metal layer Sa to completely overlap with the first sub-coil 211, and the projection of the second coil 220 on the second metal layer Sb to completely overlap with the second sub-coil 212, thereby improving the coupling coefficient between the second coil 220 and the first coil 210.

[0052] In some embodiments, the third sub-coil 221 and the fourth sub-coil 222 are formed between the first sub-coil 211 and the second sub-coil 212, and the third sub-coil 221 can generate strong electromagnetic induction with the first sub-coil 211 and the second sub-coil 212, and the fourth sub-coil 222 can generate strong electromagnetic induction with the first sub-coil 211 and the second sub-coil 212, thereby further increasing the area and coupling coefficient of electromagnetic induction between the second coil 220 and the first coil 210.

[0053] For example, Figure 2a to Figure 2cAs shown, the first end of the first sub-coil 211 and the first end of the second sub-coil 212 are connected through the first metal body T1 connecting the first metal layer Sa and the second metal layer Sb, and the first end of the first sub-coil 211 and the first end of the second sub-coil 212 are connected to the first output end of the differential amplifier circuit; the second end of the first sub-coil 211 and the second end of the second sub-coil 212 are connected through the second metal body T2 connecting the first metal layer Sa and the second metal layer Sb, and the second end of the first sub-coil 211 and the second end of the second sub-coil 212 are connected to the second output end of the differential amplifier circuit. To achieve the parallel connection of the first sub-coil 211 and the second sub-coil 212 and the connection with the differential amplifier circuit. The first metal body T1 and the second metal body T2 can be metal through holes that penetrate the first metal layer Sa and the second metal layer Sb of the substrate.

[0054] In some embodiments, Figure 2b As shown, the metal layer between the first metal layer Sa and the second metal layer Sb includes a third metal layer Sc and a fourth metal layer Sd, wherein the third metal layer Sc is arranged close to the first metal layer Sa relative to the fourth metal layer Sd, and the fourth metal layer Sd is arranged close to the second metal layer Sb relative to the third metal layer Sc, and the third sub-coil 221 is formed in the third metal layer Sc, and the fourth sub-coil 222 is formed in the fourth metal layer Sd. For example, for multiple metal layers of the substrate, the first sub-coil 211, the third sub-coil 221, the fourth sub-coil 222, and the second sub-coil 212 are arranged in sequence from top to bottom.

[0055] The first end of the third sub-coil 221 and the first end of the fourth sub-coil 222 are connected through the third metal body T3 (for example, a metal through hole) connecting the third metal layer Sc and the fourth metal layer Sd, the second end of the third sub-coil 221 is connected to the signal output terminal, and the second end of the fourth sub-coil 222 is connected to the ground, so as to realize the series connection of the third sub-coil 221 and the fourth sub-coil 222 and the connection with the signal output terminal.

[0056] Exemplarily, the projections of the third sub-coil 221 and the first sub-coil 211 in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil 222 and the second sub-coil 212 in the longitudinal direction at least partially overlap. The longitudinal direction is, for example, a direction perpendicular to the substrate. This allows the transformer 20 to occupy a smaller area on the substrate, and because the second coil 220 and the first coil 210 have a larger area for electromagnetic induction, they have a higher coupling coefficient, and can achieve a higher impedance conversion ratio.

[0057] In other embodiments, the metal layer between the first metal layer Sa and the second metal layer Sb includes a third metal layer Sc, the third sub-coil 221 and the fourth sub-coil 222 are formed in the third metal layer Sc, and the third sub-coil 221 and the fourth sub-coil 222 are spaced apart, the projections of the third sub-coil 221 and the first sub-coil 211 in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil 222 and the second sub-coil 212 in the longitudinal direction at least partially overlap; the first end of the third sub-coil 221 and the first end of the fourth sub-coil 222 are connected through a metal trace on the third metal layer Sc, the second end of the third sub-coil 221 is connected to the signal output end, and the second end of the fourth sub-coil 222 is connected to the ground. The third sub-coil 221 and the fourth sub-coil 222 can also be connected in series and connected to the signal output terminal; the third sub-coil 221 and the fourth sub-coil 222 can generate strong electromagnetic induction with the first sub-coil 211, and can also generate strong electromagnetic induction with the second sub-coil 212, thereby further increasing the area and coupling coefficient of electromagnetic induction between the second coil 220 and the first coil 210; and compared with the third sub-coil 221 formed in the third metal layer Sc and the fourth sub-coil 222 formed in the fourth metal layer Sd, the number of metal layers required for the transformer 20 can be reduced.

[0058] In some embodiments, the second coil 220 further includes a fifth sub-coil (not shown), which is connected in series with the third sub-coil 221 and the fourth sub-coil 222. That is, in the embodiment of the present application, the number of sub-coils connected in series with the second coil 220 may not be limited. By connecting a larger number of sub-coils in series, the impedance conversion ratio of the transformer 20 can be further improved. Optionally, the fifth sub-coil and the third sub-coil 221 and / or the fourth sub-coil 222 are formed in the same metal layer; or the third sub-coil 221, the fourth sub-coil 222, and the fifth sub-coil are each formed in a different metal layer. For example, for multiple metal layers of a substrate, the first sub-coil 211, the third sub-coil 221, the fourth sub-coil 222, the fifth sub-coil, and the second sub-coil 212 are arranged in sequence from top to bottom.

[0059] In some embodiments, Figure 2a to Figure 2c As shown, the first sub-coil 211, the second sub-coil 212, the third sub-coil 221, and the fourth sub-coil 222 are all circular metal wires. The induction area corresponding to the circular coil is larger than the induction area corresponding to the square coil of the same size, so the magnetic flux of the circular coil (the magnetic flux φ is equal to the magnetic induction intensity B multiplied by the induction area S) is larger; it can not only improve the coupling coefficient of the transformer 20, but also reduce the overall insertion loss of the transformer 20, thereby improving the insertion loss and power added efficiency (PAE) of the signal output link corresponding to the RF power amplifier.

[0060] In other embodiments, the first sub-coil 211, the second sub-coil 212, the third sub-coil 221, and the fourth sub-coil 222 are all polygonal metal routings, and the angle between adjacent metal segments in the polygonal metal routing is greater than 90 degrees and less than 180 degrees. This can reduce the power reflection and power loss of the first coil 210 and the second coil 220 of the transformer 20, improve power transmission and conversion efficiency, reduce the overall insertion loss of the transformer 20, and thus improve the insertion loss and power added efficiency (PAE) of the signal output link corresponding to the RF power amplifier.

[0061] In some embodiments, Figure 3 As shown, the transformer 20 also includes a first capacitor 230, a first end of the first capacitor 230 is connected to the midpoint of the first sub-coil 211 and / or the midpoint of the second sub-coil 212, and a second end of the first capacitor 230 is grounded. The first capacitor 230 is set to be connected to the ground at the central symmetrical point of the first coil 210 of the transformer 20, which can improve the balance of the transformer 20 and improve the impedance matching effect of the differential power amplifier circuit 10a. Among them, the midpoint of the first sub-coil 211 and the midpoint of the second sub-coil 212 can be grounded through the same first capacitor 230, or can be grounded through different capacitors. The midpoint of the first sub-coil 211 and the midpoint of the second sub-coil 212 are grounded through the same first capacitor 230, which is conducive to the miniaturization design of the RF power amplifier, and the first coil 210 has better balance.

[0062] For example, Figure 4a As shown, the first sub-coil 211 is symmetrical about the first axis, and the first axis is the axis where the midpoint of the first sub-coil 211 and the center of the area formed by the winding of the first sub-coil 211 are located; the second sub-coil 212 is symmetrical about the second axis, and the second axis is the axis where the midpoint of the second sub-coil 212 and the center of the area formed by the winding of the second sub-coil 212 are located. The midpoint of the first sub-coil 211 is on the symmetry axis of the first sub-coil 211, and the midpoint of the second sub-coil 212 is on the symmetry axis of the second sub-coil 212. The first capacitor 230 is connected to the ground at the midpoint of the first sub-coil 211 and / or the midpoint of the second sub-coil 212, which can further improve the balance of the transformer 20.

[0063] Optionally, the projection of the first capacitor 230 on the first metal layer Sa is located inside the area formed by the winding of the first sub-coil 211; the projection of the first capacitor 230 on the second metal layer Sb is located inside the area formed by the winding of the second sub-coil 212. The first capacitor 230 can be arranged inside the area formed by the winding of the coil of the transformer 20 to reduce the occupied area of ​​the transformer 20 and facilitate the wiring connection of the first coil 210 of the transformer 20 and the first capacitor 230, which is conducive to the miniaturized design of the power amplifier.

[0064] Optionally, the projection of the first capacitor 230 on the first metal layer Sa is located outside the area formed by the winding of the first sub-coil 211; the projection of the first capacitor 230 on the second metal layer Sb is located outside the area formed by the winding of the second sub-coil 212. The first capacitor 230 can be arranged outside the area formed by the winding of the coil of the transformer 20 to prevent the coupling between the first coil 210 and the second coil 220 of the transformer 20 from being reduced due to the coupling between the first capacitor 230 and the coil of the transformer 20.

[0065] Optionally, the first capacitor 230 may be partially disposed inside the region formed by winding the coil of the transformer 20 and partially disposed outside the region formed by winding the coil of the transformer 20 .

[0066] In some embodiments, see Figures 4a to 4d The second end of the first capacitor 230 is grounded through a grounding structure 240. The grounding structure 240 includes a plurality of metal plates 241 and metal through holes 242. The plurality of metal plates 241 are formed on different metal layers, and the metal through holes 242 connect the plurality of metal plates 241. There is a capacitive effect between the plurality of metal plates 241, which can increase the capacitance value on the basis of the first capacitor 230, and thus the first capacitor 230 can adopt a capacitor with a smaller capacitance value and a smaller size.

[0067] In some embodiments, the first capacitor 230 may be an SMD (Surface Mount Device) capacitor; in other embodiments, the first capacitor 230 may be a stacked capacitor disposed on a substrate. It should be noted that, compared to the first capacitor 230 being a stacked capacitor, the first capacitor 230 being an SMD capacitor and being grounded through a grounding structure 240 occupies a smaller area on the substrate, which is beneficial to the miniaturization design of the RF power amplifier.

[0068] In some embodiments, see Figures 4a to 4c The projection of the grounding structure 240 on the first metal layer Sa is located inside the area formed by the winding of the first sub-coil 211; the projection of the grounding structure 240 on the second metal layer Sb is located inside the area formed by the winding of the second sub-coil 212. The grounding structure 240 can be arranged inside the area formed by the winding of the coil of the transformer 20 to reduce the occupied area of ​​the transformer 20 and facilitate the wiring connection of the first coil 210 and the first capacitor 230 of the transformer 20 and the grounding structure 240, which is conducive to the miniaturized design of the power amplifier.

[0069] In some other embodiments, see Figure 4dThe projection of the grounding structure 240 on the first metal layer Sa is located outside the area formed by the winding of the first sub-coil 211; the projection of the grounding structure 240 on the second metal layer Sb is located outside the area formed by the winding of the second sub-coil 212. The grounding structure 240 can be arranged outside the area formed by the winding of the coils of the transformer 20 to prevent the coupling between the first coil 210 and the second coil 220 of the transformer 20 from being reduced due to the coupling between the grounding structure 240 and the coils of the transformer 20.

[0070] In some embodiments, the first end of the first coil 210 extends along the first direction, and / or the second end of the first coil 210 extends along the first direction; the first end of the second coil 220 extends along the second direction, and / or the second end of the second coil 220 extends along the second direction; wherein the intersection angle between the first direction and the second direction is greater than or equal to 30 degrees and less than or equal to 180 degrees. For example, the intersection angle between the first direction and the second direction is greater than or equal to 60 degrees and less than or equal to 180 degrees, or the intersection angle between the first direction and the second direction is greater than or equal to 30 degrees and less than or equal to 150 degrees. Or, the intersection angle between the first direction and the second direction is greater than or equal to 60 degrees and less than or equal to 120 degrees; preferably, the intersection angle between the first direction and the second direction can be 60 degrees, 90 degrees, 120 degrees or 180 degrees.

[0071] like Figure 2a As shown, the intersection angle of the first direction and the second direction is 180 degrees. For example, the differential power amplifier circuit 10a and the signal output terminal can be arranged on opposite sides of the transformer 20, such as the left side of the transformer 20 is connected to the differential power amplifier circuit 10a, and the right side of the transformer 20 is connected to the signal output terminal. There is a large distance between the differential power amplifier circuit 10a and the signal output terminal, which can prevent radio frequency signal interference between the differential power amplifier circuit 10a and the signal output terminal.

[0072] like Figure 4c As shown, the intersection angle of the first direction and the second direction is 90 degrees. For example, the differential power amplifier circuit 10a and the signal output terminal can be arranged on two adjacent sides of the transformer 20, such as the right side of the transformer 20 is connected to the differential power amplifier circuit 10a, and the lower side of the transformer 20 is connected to the signal output terminal. This can reduce the size of the RF power amplifier in any direction, making it easier to layout the RF power amplifier on the substrate.

[0073] In some embodiments, please combine Figure 3 See also Figure 5, the RF power amplifier includes a first bonding wire L1 and a second bonding wire L2, the first end of the first coil 210 is connected to the first output end of the differential power amplifier circuit 10a through the first bonding wire L1, and the second end of the first coil 210 is connected to the second output end of the differential power amplifier circuit 10a through the second bonding wire L2. The first bonding wire L1 and the second bonding wire L2 can be equivalent to inductors to perform impedance matching on the RF signal output by the differential power amplifier circuit 10a. Exemplarily, the first end of the first coil 210 is connected to the first output end of the differential power amplifier circuit 10a through a capacitor connected in series with the first bonding wire L1, and the second end of the first coil 210 is connected to the second output end of the differential power amplifier circuit 10a through another capacitor connected in series with the second bonding wire L2. The series capacitors can be set on the substrate, or can be integrated with the differential power amplifier circuit 10a on the power amplifier chip.

[0074] In some embodiments, the number of the first bonding wires L1 may be one or more. The number of the second bonding wires L2 may also be one or more.

[0075] In some embodiments, please combine Figure 3 See also Figure 5 The RF power amplifier also includes a second capacitor C2, the first end of the second coil 220 is connected to the signal output end through the second capacitor C2, and the second capacitor C2 is arranged adjacent to the first end of the second coil 220 relative to the second end of the second coil 220; and / or, the RF power amplifier also includes a third capacitor C3, the second end of the second coil 220 is grounded through the third capacitor C3, and the third capacitor C3 is arranged adjacent to the second end of the second coil 220 relative to the first end of the second coil 220.

[0076] The second capacitor C2 and the third capacitor C3 can perform impedance matching on the RF signal output by the transformer 20. The second capacitor C2 and the third capacitor C3 can also form a harmonic suppression circuit with the equivalent inductance of the transformer 20; the output end of the power amplifier circuit is a high-power output, which is easy to excite nonlinear components, so the harmonic suppression circuit formed by the second capacitor C2 and the third capacitor C3 and the equivalent inductance of the transformer can better suppress the harmonic components of the output end of the power amplifier circuit.

[0077] The second capacitor C2 and the third capacitor C3 are arranged close to the corresponding end of the second coil 220, which is conducive to the miniaturization of the RF power amplifier and can prevent the metal wiring or bonding wire from bringing parasitic impedance and reducing the impedance matching effect.

[0078] Exemplarily, the first end and the second end of the first coil 210 are arranged close to the differential power amplifier circuit 10a, and the first end and the second end of the second coil 220 are arranged close to the second capacitor C2 and the third capacitor C3; for example, the angle between the first direction and the second direction can be flexibly adjusted according to the positions of the differential power amplifier circuit 10a, the second capacitor C2, and the third capacitor C3. For example, Figure 5 As shown, the differential power amplifier circuit 10a is arranged on the right side of the transformer 20, and the second capacitor C2 and the third capacitor C3 are arranged on the lower side of the transformer 20. The first end and the second end of the first coil 210 are arranged on the right side of the transformer 20, and the first end and the second end of the second coil 220 are arranged on the lower side of the transformer 20, so as to facilitate the connection and layout design between the transformer 20 and the differential power amplifier circuit 10a, and the second capacitor C2 and the third capacitor C3.

[0079] The radio frequency power amplifier provided in the embodiment of the present application includes a differential power amplifier circuit 10a and a transformer 20; the input end of the differential power amplifier circuit 10a is used to input a radio frequency signal, the differential power amplifier circuit 10a is used to amplify the radio frequency signal, and the first output end and the second output end of the differential power amplifier circuit 10a are used to output the amplified radio frequency signal; the transformer 20 includes a first coil 210 and a second coil 220, the second coil 220 is coupled to the first coil 210, the first output end of the differential amplifier circuit is connected to the first end of the first coil 210, the second output end of the differential amplifier circuit is connected to the second end of the first coil 210, the first end of the second coil 220 is connected to the signal output end, and the second end of the second coil 220 is connected to the ground ; wherein the first coil 210 at least includes a first sub-coil 211 and a second sub-coil 212, the first sub-coil 211 is formed on the first metal layer Sa, the second sub-coil 212 is formed on the second metal layer Sb, and the first sub-coil 211 and the second sub-coil 212 are connected in parallel; the second coil 220 at least includes a third sub-coil 221 and a fourth sub-coil 222, the third sub-coil 221 and the fourth sub-coil 222 are formed in the metal layer between the first metal layer Sa and the second metal layer Sb, and the projection of the second coil 220 on the first metal layer Sa at least partially overlaps with the first sub-coil 211, the projection of the second coil 220 on the second metal layer Sb at least partially overlaps with the second sub-coil 212, and the third sub-coil 221 and the fourth sub-coil 222 are connected in series. The first sub-coil 211 and the second sub-coil 212 are connected in parallel to reduce the inductance of the first coil 210, and the third sub-coil 221 and the fourth sub-coil 222 are connected in series to increase the inductance of the second coil 220, so that the transformer 20 can achieve a higher impedance conversion ratio, thereby improving the power added efficiency of the RF power amplifier to increase the power of the RF signal, thereby making the RF signal have higher power and coverage distance.

[0080] Please refer to the above examples. Figure 6 ,like Figure 6 Shown is a schematic diagram of a radio frequency power amplifier provided in another embodiment of the present application.

[0081] like Figure 6 As shown, the radio frequency power amplifier includes: a power amplifier circuit 10 and a transformer 20.

[0082] The input end of the power amplifier circuit 10 is used to input a radio frequency signal, the power amplifier circuit 10 is used to amplify the radio frequency signal, and the output end of the power amplifier circuit 10 is used to output the amplified radio frequency signal; the transformer 20 includes a first coil 210 and a second coil 220, the second coil 220 is coupled to the first coil 210, the output end of the power amplifier circuit 10 is connected to the first coil 210, and the second coil 220 is used to output the radio frequency signal after impedance transformation;

[0083] Among them, the first coil 210 at least includes a first sub-coil 211 and a second sub-coil 212, the first sub-coil 211 is formed on the first metal layer Sa, the second sub-coil 212 is formed on the second metal layer Sb, and the first sub-coil 211 and the second sub-coil 212 are connected in parallel; the second coil 220 at least includes a third sub-coil 221 and a fourth sub-coil 222, the third sub-coil 221 and the fourth sub-coil 222 are formed in the metal layer between the first metal layer Sa and the second metal layer Sb, and the projection of the second coil 220 on the first metal layer Sa at least partially overlaps with the first sub-coil 211, the projection of the second coil 220 on the second metal layer Sb at least partially overlaps with the second sub-coil 212, and the third sub-coil 221 and the fourth sub-coil 222 are connected in series.

[0084] The embodiments of the present application Figure 1 The difference between the illustrated embodiments is that the embodiment of the present application does not limit the type of the power amplifier circuit 10. For example, the power amplifier circuit 10 may be a balanced power amplifier circuit, a single-ended power amplifier circuit, a Doherty power amplifier circuit, or other power amplifier circuits that require power supply. For ease of description, the embodiment of the present application mainly takes a single-ended power amplifier circuit as an example for description.

[0085] like Figure 7 As shown, the power amplifier circuit 10 includes a single-ended power amplifier circuit 10b, the output end of the single-ended power amplifier circuit 10b is connected to the first end of the first coil 210, the second end of the first coil 210 is grounded, the first end of the second coil 220 is connected to the signal output end, and the second end of the second coil 220 is grounded.

[0086] Exemplarily, the projection of the second sub-coil 212 on the first metal layer Sa at least partially overlaps with the first sub-coil 211; the first end of the first sub-coil 211 and the first end of the second sub-coil 212 are connected through a first metal body T1 connecting the first metal layer Sa and the second metal layer Sb, and the first end of the first sub-coil 211 and the first end of the second sub-coil 212 are connected to the output end of the single-ended power amplifier circuit 10b; the second end of the first sub-coil 211 and the second end of the second sub-coil 212 are connected through a second metal body T2 connecting the first metal layer Sa and the second metal layer Sb, and the second end of the first sub-coil 211 and the second end of the second sub-coil 212 are grounded.

[0087] In some embodiments, the metal layer between the first metal layer Sa and the second metal layer Sb includes a third metal layer Sc, the third sub-coil 221 and the fourth sub-coil 222 are formed in the third metal layer Sc, and the third sub-coil 221 and the fourth sub-coil 222 are spaced apart, the projections of the third sub-coil 221 and the first sub-coil 211 in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil 222 and the second sub-coil 212 in the longitudinal direction at least partially overlap; the first end of the third sub-coil 221 and the first end of the fourth sub-coil 222 are connected through a metal trace on the third metal layer Sc, the second end of the third sub-coil 221 is connected to the signal output end, and the second end of the fourth sub-coil 222 is connected to the ground.

[0088] In some embodiments, the metal layer between the first metal layer Sa and the second metal layer Sb includes a third metal layer Sc and a fourth metal layer Sd, wherein the third metal layer Sc is arranged close to the first metal layer Sa relative to the fourth metal layer Sd, and the fourth metal layer Sd is arranged close to the second metal layer Sb relative to the third metal layer Sc, the third sub-coil 221 is formed in the third metal layer Sc, and the fourth sub-coil 222 is formed in the fourth metal layer Sd; the first end of the third sub-coil 221 is connected to the first end of the fourth sub-coil 222 through the third metal body T3 connecting the third metal layer Sc and the fourth metal layer Sd, the second end of the third sub-coil 221 is connected to the signal output end, and the second end of the fourth sub-coil 222 is connected to the ground; the projections of the third sub-coil 221 and the first sub-coil 211 in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil 222 and the second sub-coil 212 in the longitudinal direction at least partially overlap.

[0089] In some embodiments, the first end of the first coil 210 extends along the first direction, and / or the second end of the first coil 210 extends along the first direction; the first end of the second coil 220 extends along the second direction, and / or the second end of the second coil 220 extends along the second direction; wherein the intersection angle of the first direction and the second direction is greater than or equal to 30 degrees and less than or equal to 180 degrees.

[0090] The specific principles and implementation methods of the RF power amplifier provided in the embodiment of the present application are similar to those of the RF power amplifier in the aforementioned embodiment, and will not be repeated here.

[0091] Please refer to the above examples. Figure 8 ,like Figure 8 Shown is a schematic block diagram of a radio frequency front-end module provided in an embodiment of the present application; the radio frequency front-end module includes the aforementioned radio frequency power amplifier.

[0092] In some embodiments, the RF front-end module may also include at least one of a RF switch, a low noise amplifier, a filter, etc., which may be integrated into one module to improve integration and performance and miniaturize the volume.

[0093] In some embodiments, Figure 1 As shown, the RF front-end module includes a substrate and an RF front-end circuit arranged on the substrate 200. The RF front-end circuit may include a switching circuit, a filter, a low-noise amplifier, and an RF power amplifier between the RF receiving port RX, the RF transmitting port TX, and the antenna port. The RF signal transmission path is formed through the above-mentioned RF devices.

[0094] The RF front-end circuit can choose to send RF signals to the antenna port or receive RF signals from the antenna port to achieve amplification, filtering and other processing of the RF analog signal.

[0095] As an implementation method, the RF front-end module may include multiple chips, and the multiple chips include at least a RF power amplifier chip integrated with the above-mentioned RF power amplifier. Furthermore, the RF front-end module may also include at least one other chip such as a low-noise amplifier chip, a control chip, a switch chip, and a filter chip.

[0096] Exemplarily, different chips may adopt different processes. For example, the low-noise amplifier chip and the control chip may adopt at least one of the silicon on insulator (SOI) process, the high electron mobility transistor (HEMT) process, and the pseudomorphic high electron mobility transistor (PHEMT) process; the RF power amplifier chip may adopt the HBT (heterojunction bipolar transistor) process, also known as the HBT chip, and the control chip may adopt the CMOS process, also known as the CMOS chip.

[0097] Exemplarily, the RF front-end module may further include a filter chip, in which one or more filters may be integrated to form a single filter, a duplexer or a multiplexer for filtering RF signals.

[0098] The specific principles and implementation methods of the RF front-end module provided in the embodiment of the present application are similar to those of the RF power amplifier in the aforementioned embodiment and will not be repeated here.

[0099] Please refer to the above examples. Fig.10 ,like Fig.10 FIG. 1 is a schematic block diagram of an electronic device provided by another embodiment of the present application. The electronic device includes the aforementioned radio frequency power amplifier; or includes the aforementioned radio frequency front-end module.

[0100] The electronic device may be a communication device such as a mobile phone, a tablet computer, a vehicle-mounted terminal, or of course, may also be other communication devices with communication functions. The embodiments of the present application do not limit the specific type of the electronic device.

[0101] The specific principles and implementation methods of the electronic device provided in the embodiments of the present application are similar to those of the RF power amplifier or RF front-end module in the aforementioned embodiments and will not be repeated here.

[0102] It should be understood that the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0103] It should 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 may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. 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. It should be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0104] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0105] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0106] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A radio frequency power amplifier, characterized in that: The radio frequency power amplifier comprises: A differential power amplifier circuit, wherein the input end of the differential power amplifier circuit is used to input a radio frequency signal, the differential power amplifier circuit is used to amplify the radio frequency signal, and the first output end and the second output end of the differential power amplifier circuit are used to output the amplified radio frequency signal; A transformer, the transformer comprising a first coil and a second coil, the second coil and the first coil are coupled to each other, the first output end of the differential amplifier circuit is connected to the first end of the first coil, the second output end of the differential amplifier circuit is connected to the second end of the first coil, the first end of the second coil is connected to the signal output end, and the second end of the second coil is connected to ground; Among them, the first coil at least includes a first sub-coil and a second sub-coil, the first sub-coil is formed in a first metal layer, the second sub-coil is formed in a second metal layer, and the first sub-coil and the second sub-coil are connected in parallel; the second coil at least includes a third sub-coil and a fourth sub-coil, the third sub-coil and the fourth sub-coil are formed in a metal layer between the first metal layer and the second metal layer, and a projection of the second coil on the first metal layer at least partially overlaps with the first sub-coil, a projection of the second coil on the second metal layer at least partially overlaps with the second sub-coil, and the third sub-coil and the fourth sub-coil are connected in series.

2. The radio frequency power amplifier according to claim 1, characterized in that: The projection of the second sub-coil on the first metal layer at least partially overlaps with the first sub-coil; The routing width of the first sub-coil is greater than or equal to the sum of the routing width of the third sub-coil and the routing width of the fourth sub-coil; and / or The routing width of the second sub-coil is greater than or equal to the sum of the routing width of the third sub-coil and the routing width of the fourth sub-coil.

3. The radio frequency power amplifier according to claim 2, characterized in that: The first end of the first sub-coil and the first end of the second sub-coil are connected through a first metal body connecting the first metal layer and the second metal layer, and the first end of the first sub-coil and the first end of the second sub-coil are connected to the first output end of the differential amplifier circuit; The second end of the first sub-coil and the second end of the second sub-coil are connected through a second metal body connecting the first metal layer and the second metal layer, and the second end of the first sub-coil and the second end of the second sub-coil are connected to the second output end of the differential amplifier circuit.

4. The radio frequency power amplifier according to claim 1, characterized in that: The metal layer between the first metal layer and the second metal layer includes a third metal layer, the third sub-coil and the fourth sub-coil are formed in the third metal layer, and the third sub-coil and the fourth sub-coil are arranged at intervals, the projections of the third sub-coil and the first sub-coil in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil and the second sub-coil in the longitudinal direction at least partially overlap; The first end of the third sub-coil is connected to the first end of the fourth sub-coil through a metal trace on the third metal layer, the second end of the third sub-coil is connected to the signal output end, and the second end of the fourth sub-coil is connected to the ground.

5. The radio frequency power amplifier according to claim 1, characterized in that: The metal layer between the first metal layer and the second metal layer includes a third metal layer and a fourth metal layer, wherein the third metal layer is arranged close to the first metal layer relative to the fourth metal layer, the fourth metal layer is arranged close to the second metal layer relative to the third metal layer, the third sub-coil is formed in the third metal layer, and the fourth sub-coil is formed in the fourth metal layer; The first end of the third sub-coil is connected to the first end of the fourth sub-coil through a third metal body connecting the third metal layer and the fourth metal layer, the second end of the third sub-coil is connected to the signal output end, and the second end of the fourth sub-coil is connected to the ground; The projections of the third sub-coil and the first sub-coil in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil and the second sub-coil in the longitudinal direction at least partially overlap.

6. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The second coil further includes a fifth sub-coil, and the fifth sub-coil is connected in series with the third sub-coil and the fourth sub-coil; The fifth sub-coil and the third sub-coil and / or the fourth sub-coil are formed in the same metal layer; or The third sub-coil, the fourth sub-coil, and the fifth sub-coil are respectively formed in different metal layers.

7. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The transformer further includes a first capacitor, a first end of the first capacitor is connected to a midpoint of the first sub-coil and / or a midpoint of the second sub-coil, and a second end of the first capacitor is grounded.

8. The radio frequency power amplifier according to claim 7, characterized in that: The first sub-coil is symmetrical about a first axis, and the first axis is an axis where the midpoint of the first sub-coil and the center of the area formed by winding the first sub-coil are located; The second sub-coil is symmetrical about a second axis, and the second axis is an axis where a midpoint of the second sub-coil and a center of an area formed by winding the second sub-coil are located.

9. The radio frequency power amplifier according to claim 7, characterized in that: The projection of the first capacitor on the first metal layer is located inside the area formed by winding the first sub-coil; the projection of the first capacitor on the second metal layer is located inside the area formed by winding the second sub-coil; or The projection of the first capacitor on the first metal layer is located outside the area formed by the winding of the first sub-coil; the projection of the first capacitor on the second metal layer is located outside the area formed by the winding of the second sub-coil.

10. The radio frequency power amplifier according to claim 7, characterized in that: The second end of the first capacitor is grounded through a grounding structure, wherein the grounding structure includes a plurality of metal plates and metal through holes, wherein the plurality of metal plates are formed in different metal layers, and the metal through holes are connected to the plurality of metal plates.

11. The radio frequency power amplifier according to claim 10, characterized in that: The projection of the grounding structure on the first metal layer is located inside the area formed by the winding of the first sub-coil; the projection of the grounding structure on the second metal layer is located inside the area formed by the winding of the second sub-coil; or The projection of the grounding structure on the first metal layer is located outside the area formed by the winding of the first sub-coil; the projection of the grounding structure on the second metal layer is located outside the area formed by the winding of the second sub-coil.

12. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The first end of the first coil extends along the first direction, and / or the second end of the first coil extends along the first direction; The first end of the second coil extends along the second direction, and / or the second end of the second coil extends along the second direction; The intersection angle between the first direction and the second direction is greater than or equal to 30 degrees and less than or equal to 180 degrees.

13. The radio frequency power amplifier according to claim 12, characterized in that: The RF power amplifier includes a first bonding wire and a second bonding wire, the first end of the first coil is connected to the first output end of the differential power amplifier circuit through the first bonding wire, and the second end of the first coil is connected to the second output end of the differential power amplifier circuit through the second bonding wire.

14. The radio frequency power amplifier according to claim 13, characterized in that: The RF power amplifier further includes a second capacitor, the first end of the second coil is connected to the signal output end through the second capacitor, and the second capacitor is arranged adjacent to the first end of the second coil relative to the second end of the second coil; And / or, the RF power amplifier further includes a third capacitor, the second end of the second coil is grounded via the third capacitor, and the third capacitor is arranged adjacent to the second end of the second coil relative to the first end of the second coil.

15. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The first sub-coil, the second sub-coil, the third sub-coil, and the fourth sub-coil are all circular metal wirings; or The first sub-coil, the second sub-coil, the third sub-coil, and the fourth sub-coil are all polygonal metal routings, and the angle between adjacent metal segments in the polygonal metal routing is greater than 90 degrees and less than 180 degrees.

16. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The transformer is disposed on a substrate, and the first metal layer, the second metal layer, and the metal layer between the first metal layer and the second metal layer are metal layers on the substrate; or The transformer is arranged on an integrated passive device chip.

17. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: An impedance conversion ratio between the first coil and the second coil is greater than or equal to 1:5 and less than or equal to 1:

3.

18. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The turns ratio of the first coil to the second coil is greater than or equal to 1:4 and less than or equal to 1:

1.

19. The radio frequency power amplifier according to any one of claims 1 to 5, characterized in that: The operating frequency of the power amplifier circuit and the transformer is greater than or equal to 3.3 GHz and less than or equal to 5 GHz.

20. The radio frequency power amplifier according to claim 19, characterized in that: The supply voltage of the radio frequency power amplifier is greater than or equal to 3V and less than or equal to 4V.

21. A radio frequency power amplifier, characterized in that: The radio frequency power amplifier comprises: A power amplifier circuit, wherein the input end of the power amplifier circuit is used to input a radio frequency signal, the power amplifier circuit is used to amplify the radio frequency signal, and the output end of the power amplifier circuit is used to output the amplified radio frequency signal; A transformer, the transformer comprising a first coil and a second coil, the second coil and the first coil are coupled to each other, the output end of the power amplifier circuit is connected to the first coil, and the second coil is used to output the radio frequency signal after impedance transformation; Among them, the first coil at least includes a first sub-coil and a second sub-coil, the first sub-coil is formed in a first metal layer, the second sub-coil is formed in a second metal layer, and the first sub-coil and the second sub-coil are connected in parallel; the second coil at least includes a third sub-coil and a fourth sub-coil, the third sub-coil and the fourth sub-coil are formed in a metal layer between the first metal layer and the second metal layer, and a projection of the second coil on the first metal layer at least partially overlaps with the first sub-coil, a projection of the second coil on the second metal layer at least partially overlaps with the second sub-coil, and the third sub-coil and the fourth sub-coil are connected in series.

22. The radio frequency power amplifier according to claim 21, characterized in that: The power amplifier circuit includes a single-ended power amplifier circuit, the output end of the single-ended power amplifier circuit is connected to the first end of the first coil, the second end of the first coil is grounded, the first end of the second coil is connected to the signal output end, and the second end of the second coil is grounded.

23. The radio frequency power amplifier according to claim 22, characterized in that: The projection of the second sub-coil on the first metal layer at least partially overlaps with the first sub-coil; The first end of the first sub-coil and the first end of the second sub-coil are connected through a first metal body connecting the first metal layer and the second metal layer, and the first end of the first sub-coil and the first end of the second sub-coil are connected to the output end of the single-ended power amplifier circuit; The second end of the first sub-coil and the second end of the second sub-coil are connected through a second metal body connecting the first metal layer and the second metal layer, and the second end of the first sub-coil and the second end of the second sub-coil are grounded.

24. The radio frequency power amplifier according to claim 21, characterized in that: The metal layer between the first metal layer and the second metal layer includes a third metal layer, the third sub-coil and the fourth sub-coil are formed in the third metal layer, and the third sub-coil and the fourth sub-coil are arranged at intervals, the projections of the third sub-coil and the first sub-coil in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil and the second sub-coil in the longitudinal direction at least partially overlap; The first end of the third sub-coil is connected to the first end of the fourth sub-coil through a metal trace on the third metal layer, the second end of the third sub-coil is connected to the signal output end, and the second end of the fourth sub-coil is connected to the ground.

25. The radio frequency power amplifier according to claim 21, characterized in that: The metal layer between the first metal layer and the second metal layer includes a third metal layer and a fourth metal layer, wherein the third metal layer is arranged close to the first metal layer relative to the fourth metal layer, the fourth metal layer is arranged close to the second metal layer relative to the third metal layer, the third sub-coil is formed in the third metal layer, and the fourth sub-coil is formed in the fourth metal layer; The first end of the third sub-coil is connected to the first end of the fourth sub-coil through a third metal body connecting the third metal layer and the fourth metal layer, the second end of the third sub-coil is connected to the signal output end, and the second end of the fourth sub-coil is connected to the ground; The projections of the third sub-coil and the first sub-coil in the longitudinal direction at least partially overlap, and the projections of the fourth sub-coil and the second sub-coil in the longitudinal direction at least partially overlap.

26. The radio frequency power amplifier according to any one of claims 21 to 25, characterized in that: The first end of the first coil extends along the first direction, and / or the second end of the first coil extends along the first direction; The first end of the second coil extends along the second direction, and / or the second end of the second coil extends along the second direction; The intersection angle between the first direction and the second direction is greater than or equal to 30 degrees and less than or equal to 180 degrees.

27. A radio frequency front-end module, characterized in that: The RF front-end module includes a RF power amplifier as described in any one of claims 1 to 26.

28. An electronic device, characterized in that: The electronic device includes the radio frequency power amplifier according to any one of claims 1 to 26, or includes the radio frequency front-end module according to claim 27.

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