Power amplifiers, power amplification devices, RF front-end modules and electronic equipment

Abstract

This application discloses a power amplifier, a power amplification device, an RF front-end module, and an electronic device. The power amplifier includes a power amplification circuit, a matching unit, and a balun. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level. Since the impedance of the balun itself is usually low, by setting a matching unit between the balun and the power amplification circuit, the matching unit can increase the input impedance of the balun, thereby reducing the output power of the power amplifier. This allows the actual output power of the power amplifier to meet the power level specified for different power levels without affecting the operating efficiency of the power supply module, ensuring that the RF front-end module equipped with the power amplifier can operate normally.

Description

Technical Field

[0001] This application relates to the field of radio frequency technology, and more specifically, to a power amplifier, a power amplification device, a radio frequency front-end module, and electronic equipment. Background Technology

[0002] Currently, radio frequency (RF) front-end modules are widely used in wireless communication, the Internet of Things (IoT), smart homes, and other fields. They can process RF signals (e.g., power amplification, modulation and demodulation) to complete the tasks of receiving and transmitting RF signals.

[0003] In existing radio frequency (RF) front-end modules, the power amplifier (PA) plays a crucial role in amplifying the power of RF signals. To improve efficiency, PAs typically use higher supply voltages, but this can lead to the actual output power being far greater than the maximum transmit power specified for different power levels, thus affecting the normal operation of the RF front-end module. Summary of the Invention

[0004] This application provides a power amplifier, a power amplification device, a radio frequency front-end module, and an electronic device.

[0005] According to a first aspect of this application, an embodiment of this application provides a power amplifier, which includes a power amplification circuit, a matching unit, and a balun. The balun includes a primary side and a secondary side coupled together. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, and the power supply voltage output by the power supply module to the power amplification circuit is greater than a preset voltage threshold. The first and second output terminals are used to output a pair of radio frequency differential signals. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level.

[0006] This application provides a power amplifier, which may include a power amplification circuit, a matching unit, and a balun. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, such as an envelope tracking (ET) power supply or an average power tracking (APT) power supply. The first and second output terminals are used to output a pair of radio frequency differential signals. In other words, the power amplification circuit in this application employs a differential structure.

[0007] Since the impedance of the balun is usually low, this application sets a matching unit between the balun and the power amplifier circuit. The matching unit can increase the input impedance of the balun to reduce the output power of the power amplifier. Thus, without reducing the operating efficiency of the power module, the actual output power of the power amplifier can meet the power level specified by different power levels (that is, less than or equal to the maximum transmit power specified by different power levels), so as to ensure that the RF front-end module equipped with the power amplifier can work normally.

[0008] According to a second aspect of this application, embodiments of this application also provide a power amplifier, which includes a power amplification circuit, a matching unit, and a balun, the balun including a primary side and a secondary side coupled together. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, and the first and second output terminals are used to output a pair of radio frequency differential signals. The matching unit includes a first inductor and a second inductor. The first inductor is connected between the first output terminal and a first terminal of the primary side, and the second inductor is connected between the second output terminal and a second terminal of the primary side; wherein the inductance values ​​of the first inductor and the second inductor are both greater than or equal to 0.6nH.

[0009] This application provides a power amplifier, which may include a power amplification circuit, a matching unit, and a balun. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, such as an envelope tracking (ET) power supply or an average power tracking (APT) power supply. The first and second output terminals are used to output a pair of radio frequency differential signals. In other words, the power amplification circuit in this application employs a differential structure.

[0010] Since the impedance of the balun itself is usually low, this application can increase the input impedance of the balun by setting a first inductor and a second inductor between the balun and the power amplifier circuit, thereby reducing the output power of the power amplifier. This allows the actual output power of the power amplifier to meet the power level specified for different power levels (i.e., less than or equal to the maximum transmit power specified for different power levels) without reducing the operating efficiency of the power module, thus ensuring that the RF front-end module equipped with the power amplifier can work normally.

[0011] Specifically, the inductance values ​​of both the first inductor and the second inductor are greater than or equal to 0.6nH. For example, the inductance values ​​of the first and second inductors can be 0.6nH, 0.8nH, 1nH, etc. Therefore, in this embodiment, both the first and second inductors have relatively large inductance values, so that the input impedance of the balun can be significantly improved.

[0012] According to a third aspect of this application, embodiments of this application also provide a power amplifier, which includes a power amplification circuit, a matching unit, and a balun. The balun includes an input matching capacitor, a coupled primary side, and a secondary side. The primary side includes a first primary side segment, a second primary side segment, and a third primary side segment. The first, second, and third primary side segments are connected in series to form a first end and a second end of the primary side, respectively. The input matching capacitor is connected between the first end and the second end. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, and the first and second output terminals are used to output a pair of radio frequency differential signals. The matching unit includes a third inductor, a fourth inductor, and a matching capacitor. One end of the third inductor is connected to the first output terminal, and the other end of the third inductor is connected to the common terminal of the first and second primary side segments. One end of the fourth inductor is connected to the second output terminal, and the other end of the fourth inductor is connected to the common terminal of the second and third primary side segments. The matching capacitor is connected between the first output terminal and the second output terminal.

[0013] This application provides a power amplifier, which may include a power amplification circuit, a matching unit, and a balun. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, such as an envelope tracking (ET) power supply or an average power tracking (APT) power supply. The first and second output terminals are used to output a pair of radio frequency differential signals. In other words, the power amplification circuit in this application employs a differential structure.

[0014] Since the impedance of the balun itself is usually low, this application can increase the input impedance of the balun by setting a third inductor and a fourth inductor between the balun and the power amplifier circuit, thereby reducing the output power of the power amplifier. This allows the actual output power of the power amplifier to meet the power level specified for different power levels (i.e., less than or equal to the maximum transmit power specified for different power levels) without reducing the operating efficiency of the power module, thus ensuring that the RF front-end module equipped with the power amplifier can work normally.

[0015] Furthermore, since the other end of the third inductor is connected to the common terminal of the first primary segment and the second primary segment, and the other end of the fourth inductor is connected to the common terminal of the second primary segment and the third primary segment, the matching unit can reuse part of the inductance of the balun primary segment (that is, the equivalent inductance of the first primary segment and the third primary segment), thereby reducing the inductance of the third and fourth inductors, reducing the area occupied by the third and fourth inductors, and reducing the hardware cost of the power amplifier.

[0016] Furthermore, since the third and fourth inductors are not connected to the two ends of the primary side, but rather to the middle of the primary side, the imaginary part of the balun input impedance will shift. Therefore, this application connects a matching capacitor between the first and second output terminals. This matching capacitor can compensate for the aforementioned shift in the imaginary part, making the overall balun input impedance "resistive," thereby ensuring the transmission efficiency of the radio frequency signal.

[0017] According to a fourth aspect of this application, embodiments of this application also provide a power amplification device, which includes an envelope tracking power supply and a power amplifier. The power amplifier includes a power amplification circuit, a matching unit, and a balun. The balun includes a primary side and a secondary side coupled together. The power amplification circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is connected to the envelope tracking power supply, and the first and second output terminals are used to output a pair of radio frequency differential signals. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level.

[0018] This application provides a power amplification device, which may include an envelope tracking power supply and a power amplifier. The power amplifier includes a power amplification circuit, a matching unit, and a balun. The power supply terminal of the power amplification circuit is connected to the envelope tracking (ET) power supply, and the first and second output terminals of the power amplification circuit are used to output a pair of radio frequency differential signals. In other words, the power amplification circuit in this application employs a differential structure.

[0019] Because ET power supplies typically output higher voltages to power power amplifiers in order to improve efficiency, and baluns generally have low impedance, the output power of the power amplifier can easily become excessive. This application addresses this by adding a matching unit between the balun and the power amplifier circuit. This increases the input impedance of the balun, thereby reducing the output power of the power amplifier. This ensures that the actual output power of the power amplifier meets the power levels specified for different power ratings (i.e., less than or equal to the maximum transmit power specified for each power rating) without reducing the efficiency of the power supply module, thus guaranteeing the normal operation of the RF front-end module equipped with the power amplifier.

[0020] According to a fifth aspect of this application, embodiments of this application also provide a radio frequency (RF) front-end module, which includes a substrate, a balun, and a first chip. The balun is disposed on the substrate and includes a primary side and a secondary side coupled together. The first chip is disposed on the substrate and contains a power amplifier circuit and a matching unit. The power amplifier circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, and the power supply voltage output by the power supply module to the power amplifier circuit is greater than a preset voltage threshold. The first and second output terminals are used to output a pair of RF differential signals. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level.

[0021] This application provides a radio frequency (RF) front-end module, which may include a substrate, a balun, and a first chip. The first chip houses a power amplifier circuit and a matching unit. The power amplifier circuit has a power supply terminal, a first output terminal, and a second output terminal. The power supply terminal is used to connect to a power supply module, such as an envelope tracking (ET) power supply or an average power tracking (APT) power supply. The first and second output terminals are used to output a pair of differential RF signals. In other words, the power amplifier circuit in this application employs a differential structure.

[0022] Since the impedance of the balun is usually low, this application sets a matching unit between the balun and the power amplifier circuit. The matching unit can increase the input impedance of the balun to reduce the output power of the power amplifier. Thus, without reducing the operating efficiency of the power module, the actual output power of the power amplifier can meet the power level specified by different power levels (that is, less than or equal to the maximum transmit power specified by different power levels), so as to ensure that the RF front-end module can work normally.

[0023] According to a sixth aspect of this application, embodiments of this application also provide an electronic device, which may include the power amplifier described above; or the power amplification device described above; or a radio frequency front-end module. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1This is a schematic diagram of a power amplifier provided in an embodiment of this application.

[0026] Figure 2 This is another schematic diagram of the power amplifier provided in the embodiments of this application.

[0027] Figure 3 This is another structural schematic diagram of the power amplifier provided in the embodiments of this application.

[0028] Figure 4 yes Figure 3 The diagram shows the connection diagram of the primary side and the matching unit in the power amplifier.

[0029] Figure 5 This is another schematic diagram of the power amplifier provided in the embodiments of this application.

[0030] Figure 6 yes Figure 5 The simulation curve of the power amplifier corresponding to the balun input impedance is shown.

[0031] Figure 7 yes Figure 5 The Smith chart of the power amplifier corresponding to the balun input impedance is shown.

[0032] Figure 8 This is another structural schematic diagram of the power amplifier provided in the embodiments of this application.

[0033] Figure 9 yes Figure 8 The simulation curve of the power amplifier corresponding to the balun input impedance is shown.

[0034] Figure 10 yes Figure 8 The Smith chart of the power amplifier corresponding to the balun input impedance is shown.

[0035] Figure 11 This is a schematic diagram of the power amplifier device provided in the embodiments of this application.

[0036] Figure 12 This is a schematic diagram of the structure of the radio frequency front-end module provided in the embodiments of this application.

[0037] Figure 13 yes Figure 12 The diagram shows a structural schematic of the first inductor, the second inductor, and the control unit in the RF front-end module.

[0038] Figure 14 yes Figure 12 The diagram shows another structural schematic of the first inductor, the second inductor, and the control unit in the RF front-end module shown.

[0039] Figure 15This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0041] This application provides a power amplifier 100, which is mainly used to amplify the power of the input radio frequency signal. It can be a push-pull power amplifier, a balanced power amplifier, a Doherty power amplifier, etc.

[0042] Please see Figure 1 The power amplifier 100 may include a power amplifier circuit 10, a matching unit 30, and a balun 50. The power amplifier circuit 10 has a power supply terminal 102, a first output terminal 104, and a second output terminal 106. The power supply terminal 102 is used to connect to the power supply module 200. For example, the power supply module 200 may be an envelope tracking (ET) power supply or an average power tracking (APT) power supply. An ET power supply is one that outputs a corresponding supply voltage following the envelope of the radio frequency signal. An average power tracking power supply is a power supply module that automatically adjusts the operating voltage of the power amplifier based on the amplifier's preset output power and its own parameters.

[0043] Therefore, this embodiment can dynamically adjust the supply voltage of the power amplifier circuit 10 by setting the power module 200, thereby improving the operating efficiency of the power amplifier circuit 10. Taking the power module 200 as an ET power supply as an example, the boost module in the ET power supply will output a higher supply voltage to the power amplifier circuit 10 to improve the voltage conversion efficiency of the ET power supply and the operating efficiency of the power amplifier circuit 10.

[0044] Specifically, the power supply voltage output by the power module 200 to the power amplifier circuit 10 is greater than a preset voltage threshold. Here, the "preset voltage threshold" can be understood as the normal voltage value, that is, the power supply voltage value typically used in commercially available power amplifier products. The "preset voltage threshold" can also be understood as the minimum battery voltage of the mobile terminal equipped with the power module 200 and the power amplifier 100. For example, the preset voltage threshold is greater than or equal to 3.4V. For instance, the preset voltage threshold can be 3.4V, 3.5V, 3.6V, etc.

[0045] In some possible embodiments, the supply voltage output by the power module 200 to the power amplifier circuit 10 may be greater than or equal to 3.6V and less than or equal to 4V. In other possible embodiments, the supply voltage output by the power module 200 to the power amplifier circuit 10 may be greater than or equal to 3.8V and less than or equal to 5.2V.

[0046] Optionally, the power module 200 can receive a lower input voltage and convert it into a supply voltage higher than a preset voltage threshold via a boost module. Alternatively, the power module 200 can receive a higher input voltage and convert it into a supply voltage higher than a preset voltage threshold but lower than the input voltage via a buck module. This application does not limit the voltage conversion method of the power module 200. Specifically, the input voltage of the power module 200 can be determined based on the battery voltage of the mobile terminal equipped with the power module 200; this embodiment does not impose specific limitations on this.

[0047] The first output terminal 104 and the second output terminal 106 are used to output a pair of radio frequency differential signals. That is, the power amplifier circuit 10 in this application is implemented using a differential structure. It is used to amplify the signal power of a pair of radio frequency differential signals and output the two amplified radio frequency signals through the first output terminal 104 and the second output terminal 106, respectively. Of course, the power amplifier 100 may also include other power amplifier circuits (not shown in the figure). Other power amplifier circuits can be set in the pre-stage of the power amplifier circuit 10 in this differential architecture, forming a multi-stage power amplifier circuit with the power amplifier circuit 10.

[0048] In this embodiment, the balun 50 is used to perform impedance matching and balun conversion on a pair of radio frequency differential signals output from the power amplifier circuit 10, that is, to convert a pair of radio frequency differential signals into a single radio frequency single-ended signal. Specifically, the balun 50 may include a coupled primary side 52 and a secondary side 54. In some possible embodiments, the turns ratio of the secondary side 54 to the primary side 52 may be greater than or equal to 2 and less than or equal to 5. For example, the turns ratio of the secondary side 54 to the primary side 52 may be 2, 2.6, 3, 3.2, 4, 4.5, 5, etc.

[0049] The matching unit 30 is connected between the first output terminal 104, the second output terminal 106 and the primary side 52. It is used to increase the input impedance of the balun 50 so that the output power of the power amplifier 100 is less than or equal to the maximum transmit power corresponding to the preset power level.

[0050] Since the impedance of the balun 50 is usually low, this embodiment sets a matching unit 30 between the balun 50 and the power amplifier circuit 10. The matching unit 30 can increase the input impedance of the balun 50 to reduce the output power of the power amplifier 100, thereby enabling the actual output power of the power amplifier 100 to meet the power level specified by different power levels (that is, less than or equal to the maximum transmit power specified by different power levels), so as to ensure that the RF front-end module equipped with the power amplifier 100 can work normally.

[0051] It's important to note that in related technologies, because the impedance of the balun 50 is typically low, the actual output power of the power amplifier 100, when operating at high voltage, can be significantly higher than the maximum transmit power specified for different power levels. To ensure the normal operation of the power amplifier 100, developers often reduce the input voltage of the ET power supply. This lower input voltage reduces the output voltage of the ET power supply (i.e., the supply voltage of the power amplifier 100), thereby reducing the output power of the power amplifier. However, a lower input voltage reduces the efficiency of the ET power supply.

[0052] Therefore, to solve the above-mentioned problems, the inventors of this application have achieved high impedance matching of the balun 50 by setting a matching unit 30 between the balun 50 and the power amplifier circuit 10. On one hand, with the increased input impedance of the balun 50, the actual output power of the power amplifier 100 can be reduced, so that the actual output power can meet the power level specified for different power grades. On the other hand, since there is no need to reduce the input voltage of the ET power supply, the operating efficiency of the power module 200 can also be guaranteed.

[0053] It's easy to understand here that, since the primary side 52 of the balun 50 is connected to the matching unit 30, the input impedance Z1, the output impedance Z2, and the turns ratio n of the secondary side 54 to the primary side 52 of the balun 50 satisfy the formula: Z2 / Z1 < n 2 Without the addition of matching unit 30, the impedance transformation ratio of the balun is usually the square of the turns ratio. However, after adding matching unit 30 in this application, the impedance transformation ratio Z2 / Z1 between the secondary side 54 and the primary side 52 of the balun is adjusted to be less than the square of the turns ratio n. This increases the impedance of the primary side 52 of the balun while keeping the output impedance constant. As a result, the power of the RF signal output by the power amplifier circuit 10 is reduced after passing through matching circuit 30 and balun 50 (lower than if it passes directly through balun 50 without matching circuit 30). Thus, without reducing the operating efficiency of the power module, the actual output power of the power amplifier can meet the power level specified for different power grades.

[0054] This section explains the "power levels specified for different power grades".

[0055] In some possible embodiments, the operating frequency band of the power amplifier 100 can be a first frequency band, which can be a high frequency band (HB) with a corresponding preset power class of PowerClass2 (PC2). The maximum transmit power corresponding to this preset power class is 26dBm, that is, 400mW of transmit power.

[0056] In another possible embodiment, the power amplifier 100 can operate in a second frequency band, which can be a low-to-mid frequency (LMB) band, meaning the frequency of the first frequency band is higher than the frequency of the second frequency band. The preset power class corresponding to the second frequency band is PowerClass 3 (PC3), and the maximum transmit power corresponding to this preset power class is 23 dBm, that is, 200 mW of transmit power.

[0057] Specifically, the first frequency band can be from 3 GHz to 6 GHz. For example, the first frequency band may include the N77 band, N78 band, N79 band, etc. The second frequency band can be from 1.5 GHz to 3 GHz. For example, the second frequency band may include the B1 band, B2 band, B34 band, B38 band, B39 band, B40 band, etc.

[0058] For example, taking the first frequency band as N77 and the corresponding power class as PC2 (PowerClass2) as an example, when the power supply voltage output by the power module 200 to the power amplifier circuit 10 is too high, since the impedance of the balun 50 is usually low, if the matching unit 30 is not set, the actual output power of the power amplifier 100 will be much greater than the maximum transmit power corresponding to the power class PowerClass2 (i.e., 26dBm), thereby affecting the normal transmission of the radio frequency signal.

[0059] To solve the above problems, the inventors of this application provide a matching unit 30 at the input terminal of the balun 50 to increase the input impedance of the balun 50, thereby reducing the actual output power of the power amplifier 100, so that the actual output power of the power amplifier 100 operating in the N77 band does not exceed the maximum transmit power corresponding to PowerClass2.

[0060] The specific implementation of the power amplifier 100 is explained below.

[0061] In this embodiment, the power amplifier circuit 10 may include K first transistors and K second transistors (not shown in the figure), where K is a positive integer greater than or equal to 1. Specifically, the input terminals of the K first transistors are connected in parallel to form a first input terminal, which is used to input a first radio frequency signal. The output terminals of the K first transistors are connected in parallel to both the power supply terminal 102 and the first output terminal 104. On the one hand, the power supply voltage is received through the power supply terminal 102; on the other hand, the power-amplified first radio frequency signal is output through the first output terminal 104.

[0062] For example, the first transistor may be a heterojunction bipolar transistor (HBT), wherein the input terminal of the first transistor is the base of the HBT, the output terminal of the first transistor is the collector of the HBT, and the emitter of the HBT is grounded.

[0063] Of course, the first transistor can also be a unipolar transistor, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), a silicon-on-insulator (SOI) field-effect transistor, a pseudomorphic high electron mobility transistor (PHEMT), etc. This embodiment does not specifically limit it.

[0064] Similarly, the input terminals of the K second transistors are connected in parallel to form a second input terminal, which is used to input the second radio frequency (RF) signal. The second RF signal and the first RF signal can be a pair of RF differential signals. The output terminals of the K second transistors are connected in parallel to both the power supply terminal 102 and the second output terminal 106. On one hand, the power supply voltage is received through the power supply terminal 102; on the other hand, the amplified second RF signal is output through the second output terminal 106.

[0065] For example, the second transistor can be a heterojunction bipolar transistor (HBT), wherein the input terminal of the second transistor is the base of the HBT, the output terminal of the second transistor is the collector of the HBT, and the emitter of the HBT is grounded.

[0066] Of course, the second transistor can also be a unipolar transistor, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), a silicon-on-insulator (SOI) field-effect transistor, a pseudomodulation-doped heterojunction field-effect transistor (Pseudomorphic HEMT), etc. This embodiment does not specifically limit it.

[0067] Please see Figure 2 In some possible embodiments, the matching unit 30 may include a first inductor 310 and a second inductor 320, the first inductor 310 being connected between the first output terminal 104 and the first terminal 5201 of the primary side 52, and the second inductor 320 being connected between the second output terminal 106 and the second terminal 5203 of the primary side 52.

[0068] This embodiment, by placing a first inductor 310 and a second inductor 320 between the primary side 52 of the balun 50 and the output terminal of the power amplifier circuit 10, can increase the input impedance of the balun 50 without changing its bandwidth and turns ratio, thereby reducing the actual output power of the power amplifier 100. Even when the supply voltage received by the power amplifier circuit 10 is high, the actual output power can still meet the power level specified for different power ratings. Specifically, the specific implementation of the first inductor 310 and the second inductor 320 will be described in the following embodiments.

[0069] It is easy to understand here that, since the primary side 52 of the balun 50 in this embodiment is connected to the first inductor 310 and the second inductor 320, the input current I1, the input voltage U1, the output current I2, and the output voltage U2 of the balun 50 satisfy the following formula:

[0070]

[0071] Where L is the inductance value of the first inductor 310 and the inductance value of the second inductor 320, L p The inductance value of the primary side is 52, L s Let M be the inductance value of the secondary side 54, and M be the mutual inductance coefficient between the primary side 52 and the secondary side 54. Since the impedance value is equal to the voltage divided by the current, it can be seen from the above formula that the input impedance of the balun 50 is increased by adding the first inductor 310 and the second inductor 320.

[0072] Optionally, in Figure 2In the illustrated embodiment, the balun 50 may further include an input matching capacitor C1, a virtual ground matching capacitor C2, an output matching capacitor C3, and a ground matching capacitor C4. The input matching capacitor C1 is connected between the first terminal 5201 and the second terminal 5203. One end of the virtual ground matching capacitor C2 is connected to the midpoint of the primary side 52, and the other end is grounded. The output matching capacitor C3 is connected in series with the secondary side 54 at the end used for outputting the radio frequency signal. One end of the ground matching capacitor C4 is connected to the grounded end of the secondary side 54, and the other end is grounded.

[0073] On one hand, the aforementioned matching capacitors C1 to C4 can act as "DC blocking and AC passing" capacitors to ensure the signal quality of the radio frequency (RF) signal and prevent DC signals from affecting the RF signal. On the other hand, the aforementioned matching capacitors C1 to C4 can also adjust the impedance to ensure that the RF signal can be transmitted efficiently and stably. This embodiment does not limit the implementation method or specific values ​​of the aforementioned matching capacitors C1 to C4.

[0074] Please see Figure 3 and Figure 4 In some possible embodiments, the primary edge 52 may include a first primary edge segment 521, a second primary edge segment 523, and a third primary edge segment 525. The two ends formed by the first primary edge segment 521, the second primary edge segment 523, and the third primary edge segment 525 connected in series are respectively the first end 5201 and the second end 5203 of the primary edge 52. The balun 50 may also include an input matching capacitor C1, which is connected between the first end 5201 and the second end 5203.

[0075] The matching unit 30 may include a third inductor 330, a fourth inductor 340, and a matching capacitor 350. One end of the third inductor 330 is connected to the first output terminal 104, and the other end of the third inductor 330 is connected to the common terminal of the first primary segment 521 and the second primary segment 523. Here, "the common terminal of the first primary segment 521 and the second primary segment 523" refers to the node where the first primary segment 521 and the second primary segment 523 are connected. One end of the fourth inductor 340 is connected to the second output terminal 106, and the other end of the fourth inductor 340 is connected to the common terminal of the second primary segment 523 and the third primary segment 525. Here, "the common terminal of the second primary segment 523 and the third primary segment 525" refers to the node where the second primary segment 523 and the third primary segment 525 are connected. The matching capacitor 350 is connected between the first output terminal 104 and the second output terminal 106.

[0076] It should be noted that the first primary segment 521, the second primary segment 523, and the third primary segment 525 in this embodiment are named only for the convenience of describing the connection positions of the third inductor 330 and the fourth inductor 340. Compared to Figure 2The first inductor 310 and the second inductor 320 are connected to the two ends of the primary side 52, respectively. The third inductor 330 and the fourth inductor 340 are connected to the middle position of the primary side 52, and the connection positions of the third inductor 330 and the fourth inductor 340 on the primary side 52 are not the same. Here, the "middle position" can be any position of the primary side 52 other than the two endpoints (that is, the first end 5201 and the second end 5203).

[0077] Therefore, the two connection positions of the third inductor 330 and the fourth inductor 340 on the primary side 52 divide the primary side 52 into three segments, namely, the first primary side segment 521, the second primary side segment 523 and the third primary side segment 525.

[0078] Since the third inductor 330 and the fourth inductor 340 are respectively connected to the middle position of the primary side 52, the matching unit 30 can reuse part of the inductance of the primary side of the balun (that is, the equivalent inductance of the first primary side segment 521 and the third primary side segment 525), thereby reducing the inductance of the third inductor 330 and the fourth inductor 340, saving the area occupied by the matching unit 30, and reducing the hardware cost of the power amplifier 100.

[0079] Furthermore, since the third inductor 330 and the fourth inductor 340 are not connected to the two ends of the primary side 52, but rather to the middle position of the primary side 52, the imaginary part of the balun input impedance will shift. Therefore, this application connects a matching capacitor 350 between the first output terminal 104 and the second output terminal 106. This matching capacitor 350 can compensate for the aforementioned shift in the imaginary part of the impedance, so that the overall balun input impedance is "resistive," thereby ensuring the transmission efficiency of the radio frequency signal. Specifically, the specific implementation of the third inductor 330, the fourth inductor 340, and the matching capacitor 350 will be described in the following embodiments.

[0080] It is easy to understand here that, since the primary side 52 of the balun 50 in this embodiment is connected to the third inductor 330 and the fourth inductor 340, the input current I1, input voltage U1, output current I2, and output voltage U2 of the balun 50 satisfy the following formula:

[0081]

[0082] Where L1 represents the inductance values ​​of the third inductor 350 and the fourth inductor 340, and L2 represents the inductance values ​​of the first primary segment 521 and the third primary segment 525. p The inductance value of the primary side is 52, L sLet M be the inductance value of the secondary side 54, and M be the mutual inductance coefficient between the primary side 52 and the secondary side 54. Since the impedance value is equal to the voltage divided by the current, it can be seen from the above formula that the input impedance of the balun 50 is increased by adding the third inductor 330 and the fourth inductor 340.

[0083] Optionally, in Figure 3 In the illustrated embodiment, the balun 50 may further include a virtual ground matching capacitor C2, an output matching capacitor C3, and a ground matching capacitor C4. One end of the virtual ground matching capacitor C2 is connected to the midpoint of the primary side 52, and the other end is grounded. The output matching capacitor C3 is connected in series with the secondary side 54 at the end used for outputting the radio frequency signal. One end of the ground matching capacitor C4 is connected to the grounding end of the secondary side 54, and the other end is grounded.

[0084] On one hand, the aforementioned matching capacitors C1 to C4 can act as "DC blocking and AC passing" capacitors to ensure the signal quality of the radio frequency (RF) signal and prevent DC signals from affecting the RF signal. On the other hand, the aforementioned matching capacitors C1 to C4 can also adjust the impedance to ensure that the RF signal can be transmitted efficiently and stably. This embodiment does not limit the implementation method or specific values ​​of the aforementioned matching capacitors C1 to C4.

[0085] Please see Figure 5 This application also provides a power amplifier 100, which may include a power amplifier circuit 10, a matching unit 30, and a balun 50. The power amplifier circuit 10 has a power supply terminal 102, a first output terminal 104, and a second output terminal 106. The power supply terminal 102 is used to connect to a power module 200. For example, the power module 200 may be an envelope tracking (ET) power supply or an average power tracking (APT) power supply. For a detailed description of the power module 200, please refer to the relevant content in the above embodiments. The first output terminal 104 and the second output terminal 106 are used to output a pair of radio frequency differential signals.

[0086] In this embodiment, the balun 50 may include a coupled primary side 52 and a secondary side 54. In some possible embodiments, the turns ratio of the secondary side 54 to the primary side 52 may be greater than or equal to 2 and less than or equal to 5. For example, the turns ratio of the secondary side 54 to the primary side 52 may be 2, 3, 4, 5, etc.

[0087] The matching unit 30 may include a first inductor 310 and a second inductor 320. The first inductor 310 is connected between the first output terminal 104 and the first terminal 5201 of the primary side 52, and the second inductor 320 is connected between the second output terminal 106 and the second terminal 5203 of the primary side 52. Specifically, the first inductor 310 and the second inductor 320 are used to increase the input impedance of the balun 50 so that the output power of the power amplifier 100 is less than or equal to the maximum transmit power corresponding to a preset power level. For a detailed description of the "maximum transmit power corresponding to the preset power level," please refer to the relevant content in the above embodiments.

[0088] Since the impedance of the balun 50 is typically low, this embodiment increases the input impedance of the balun 50 without changing its bandwidth and turns ratio by placing a first inductor 310 and a second inductor 320 between the balun 50 and the power amplifier circuit 10, thereby reducing the actual output power of the power amplifier 100. Even when the supply voltage of the power amplifier circuit 10 is high, the actual output power of the power amplifier 100 can still meet the power level specified for different power levels (i.e., less than or equal to the maximum transmit power specified for different power levels), ensuring that the RF front-end module equipped with the power amplifier 100 can operate normally.

[0089] Specifically, the inductance values ​​of both the first inductor 310 and the second inductor 320 are greater than or equal to 0.6nH. For example, the inductance values ​​of the first inductor 310 and the second inductor 320 can be 0.6nH, 0.8nH, 1nH, etc. Therefore, in this embodiment, both the first inductor 310 and the second inductor 320 have relatively large inductance values, so that the input impedance of the balun 50 can be significantly improved.

[0090] In some possible embodiments, the inductance value of the first inductor 310 is equal to the inductance value of the second inductor 320 to ensure the balance of a pair of radio frequency differential signal transmissions.

[0091] In some possible embodiments, the inductance value of the first inductor 310 is less than or equal to 1.4nH. The inductance value of the second inductor 320 is less than or equal to 1.4nH. For example, the inductance values ​​of the first inductor 310 and the second inductor 320 can be 1nH, 1.2nH, 1.4nH, etc. Since the inductance values ​​of the first inductor 310 and the second inductor 320 in this embodiment do not exceed 1.4nH, the situation where the inductance values ​​of the first inductor 310 and the second inductor 320 are too large and thus affect the normal transmission of radio frequency signals can be avoided, thereby ensuring the normal operation of the power amplifier 100. Of course, in some other possible embodiments, the inductance value of the first inductor 310 is less than or equal to 1nH. The inductance value of the second inductor 320 is less than or equal to 1nH.

[0092] Please see Figure 6 and Figure 7 , Figure 6 and Figure 7 All of these are for the inventors of this application. Figure 5 The simulation results for the circuit structure shown are as follows. The inductance values ​​of the first inductor 310 and the second inductor 320 are equal. Specifically, Figure 6 The diagram shows the input impedance curves of the balun 50. The left graph shows the real part of the balun input impedance when the inductance value of the first inductor 310 is 0.3nH, 0.6nH, and 1nH; the right graph shows the imaginary part of the balun input impedance when the inductance value of the first inductor 310 is 0.3nH, 0.6nH, and 1nH. Figure 6 It is easy to see that when the inductance values ​​of the first inductor 310 are 0.3nH, 0.6nH, and 1nH, the imaginary part of the balun input impedance varies within the range of -0.5 ohms to 1 ohm, and the differences between the three are not significant. However, the real part of the balun input impedance increases as the inductance value of the first inductor 310 increases.

[0093] Specifically, when the inductance of the first inductor 310 is 0.3nH, the real part of the impedance is between 7 ohms and 8.2 ohms, and the imaginary part is between -0.5 ohms and 0.9 ohms. When the inductance of the first inductor 310 is 0.6nH, the real part of the impedance is between 11.3 ohms and 13 ohms, and the imaginary part is between -0.3 ohms and 0.8 ohms. When the inductance of the first inductor 310 is 1nH, the real part of the impedance is between 17.9 ohms and 20 ohms, and the imaginary part is between -0.2 ohms and 0.9 ohms.

[0094] Figure 7 The diagram shows the Smith charts for the balun input impedance when the inductance values ​​of the first inductor 310 are 0.3nH, 0.6nH, and 1nH. From... Figure 7 It is easy to see that, within a certain range, as the inductance value of the first inductor 310 increases, the Smith curve corresponding to the balun input impedance gets closer to the center of the circle.

[0095] exist Figure 5 In the illustrated embodiment, the power amplifier circuit 10 is integrated into the first chip 12, for example, the first chip 12 may be an HBT chip. The first chip 12, balun 50, first inductor 310 and second inductor 320 are all adapted to be disposed on a substrate (not shown in the figure). For example, the first chip 12 can be fixed on the substrate by a flip-chip process or a wire bonding process, and the balun 50 can be wound on the substrate by metal traces.

[0096] In some possible embodiments, the power amplifier 100 may further include a first connector 103 and a second connector 105. The first output terminal 104 of the power amplifier circuit 10 is connected to one end of the first inductor 310 via the first connector 103, and the other end of the first inductor 310 is connected to the first terminal 5201 of the primary side 52. The second output terminal 106 of the power amplifier circuit 10 is connected to one end of the second inductor 320 via the second connector 105, and the other end of the second inductor 320 is connected to the second terminal 5203 of the primary side 52.

[0097] Specifically, in this embodiment, the first chip 12 is connected to the first inductor 310 disposed on the substrate via the first connector 103, and the first chip 12 is connected to the second inductor 320 disposed on the substrate via the second connector 105. As one implementation, the first chip 12 is fixed to the substrate using a wire bonding process, in which case the first connector 103 and the second connector 105 can be bonding wires, respectively. Specifically, the bonding wires can be metal wires such as copper wires or silver wires. As another implementation, the first chip 12 is fixed to the substrate using an over-buck process, in which case the first connector 103 and the second connector 105 can be bumps, respectively. Specifically, the bumps can be columnar or spherical, and the material used can be copper or tin. For example, the bumps can be copper columnar or tin ball.

[0098] In this embodiment, since the inductance values ​​of both the first inductor 310 and the second inductor 320 are greater than or equal to 0.6nH, it indicates that both the first inductor 310 and the second inductor 320 have large inductance values, while the equivalent inductance of the bonding wire or bump is small and insufficient to replace the first inductor 310 and the second inductor 320. As one implementation, the first inductor 310 and the second inductor 320 can be disposed on the substrate in the form of metal traces. Specifically, researchers can adjust the inductance of the first inductor 310 and the second inductor 320 by adjusting the length of the metal traces. As another implementation, the first inductor 310 and the second inductor 320 are disposed on the substrate as surface-mount devices (SMD) to make the substrate layout more compact and reasonable.

[0099] Therefore, the first inductor 310 and the second inductor 320 in this embodiment are not inductors equivalent to the bonding wire or bump, but are additional inductors provided to increase the input impedance of the balun 50.

[0100] In some possible embodiments, both the first inductor 310 and the second inductor 320 are adjustable inductors. Specifically, the inductance values ​​of the first inductor 310 and the second inductor 320 can be dynamically adjusted according to the output power of the RF front-end module equipped with the power amplifier 100. The higher the output power of the RF front-end module, the larger the inductance values ​​of the first inductor 310 and the second inductor 320, and the higher the input impedance of the balun 50, thus limiting the output power of the RF front-end module and maintaining it within a normal power range. The implementation of adjustable inductors for the first inductor 310 and the second inductor 320 will be described in detail in the embodiments below.

[0101] Please see Figure 8 This application also provides a power amplifier 100, which may include a power amplifier circuit 10, a matching unit 30, and a balun 50. The power amplifier circuit 10 has a power supply terminal 102, a first output terminal 104, and a second output terminal 106. The power supply terminal 102 is used to connect to a power module 200. For example, the power module 200 may be an envelope tracking (ET) power supply or an average power tracking (APT) power supply. For a detailed description of the power module 200, please refer to the relevant content in the above embodiments. The first output terminal 104 and the second output terminal 106 are used to output a pair of radio frequency differential signals.

[0102] In this embodiment, the balun 50 may include an input matching capacitor C1, a coupled primary side 52, and a secondary side 54. In some possible embodiments, the turns ratio of the secondary side 54 to the primary side 52 may be greater than or equal to 2 and less than or equal to 5. For example, the turns ratio of the secondary side 54 to the primary side 52 may be 2, 3, 4, 5, etc.

[0103] Specifically, such as Figure 4 As shown, the primary side 52 may include a first primary side segment 521, a second primary side segment 523 and a third primary side segment 525. The two ends formed by the first primary side segment 521, the second primary side segment 523 and the third primary side segment 525 connected in series are the first end 5201 and the second end 5203 of the primary side 52, respectively. The input matching capacitor C1 is connected between the first end 5201 and the second end 5203.

[0104] Matching unit 30 may include a third inductor 330, a fourth inductor 340, and a matching capacitor 350. One end of the third inductor 330 is connected to the first output terminal 104, and the other end of the third inductor 330 is connected to the common terminal of the first primary segment 521 and the second primary segment 523. One end of the fourth inductor 340 is connected to the second output terminal 106, and the other end of the fourth inductor 340 is connected to the common terminal of the second primary segment 523 and the third primary segment 525. Matching capacitor 350 is connected between the first output terminal 104 and the second output terminal 106. Specifically, the third inductor 330 and the fourth inductor 340 are used to increase the input impedance of the balun 50 so that the output power of the power amplifier 100 is less than or equal to the maximum transmit power corresponding to a preset power level. For a detailed description of the "maximum transmit power corresponding to the preset power level," please refer to the relevant content in the above embodiments.

[0105] Since the impedance of the balun 50 is typically low, this embodiment increases the input impedance of the balun 50 without changing its bandwidth and turns ratio by placing a third inductor 330 and a fourth inductor 340 between the balun 50 and the power amplifier circuit 10, thereby reducing the actual output power of the power amplifier 100. Even when the supply voltage of the power amplifier circuit 10 is high, the actual output power of the power amplifier 100 can still meet the power level specified for different power levels (i.e., less than or equal to the maximum transmit power specified for different power levels), ensuring that the RF front-end module equipped with the power amplifier 100 can operate normally.

[0106] Furthermore, since the other end of the third inductor 330 is connected to the common terminal of the first primary segment 521 and the second primary segment 523, and the other end of the fourth inductor 340 is connected to the common terminal of the second primary segment 523 and the third primary segment 525, the matching unit 30 can reuse part of the inductance of the balun primary side (that is, the equivalent inductance of the first primary segment 521 and the third primary segment 525), thereby reducing the inductance of the third inductor 330 and the fourth inductor 340, and reducing the hardware cost of the power amplifier 100.

[0107] Furthermore, since the third inductor 330 and the fourth inductor 340 are not connected to the two ends of the primary side 52 (i.e., the first end 5201 and the second end 5203), but are connected to the middle of the primary side 52, the imaginary part of the balun input impedance will shift. Therefore, this application connects a matching capacitor 350 between the first output terminal 104 and the second output terminal 106. This matching capacitor 350 can compensate for the aforementioned shift in the imaginary part, so that the overall balun input impedance is "resistive," thereby ensuring the transmission efficiency of the radio frequency signal.

[0108] In some possible embodiments, the inductance value of the first primary segment 521 and the inductance value of the third primary segment 525 are equal to ensure the balance of a pair of radio frequency differential signal transmissions.

[0109] In some possible embodiments, the ratio between the inductance value of the first primary segment 521 and the inductance value of the primary side 52 is greater than or equal to 1 / 8 and less than or equal to 1 / 4. For example, the ratio can be 1 / 8, 1 / 6, 1 / 4, etc. Therefore, in this embodiment, the common terminal of the first primary segment 521 and the second primary segment 523 is located on the primary side 52 relatively close to the first terminal 5201, which can avoid causing a large offset to the imaginary part of the balun input impedance. Similarly, the ratio between the inductance value of the third primary segment 525 and the inductance value of the primary side 52 is greater than or equal to 1 / 8 and less than or equal to 1 / 4. For example, the ratio can be 1 / 8, 1 / 6, 1 / 4, etc. Therefore, in this embodiment, the common terminal of the second primary segment 523 and the first primary segment 521 is located on the primary side 52 relatively close to the second terminal 5203, which can avoid causing a large offset to the imaginary part of the balun input impedance.

[0110] In some possible embodiments, the third inductor 330 is connected to the first connection point 5207 of the primary side 52. The first connection point 5201 is located between the first end 5201 of the primary side 52 and the midpoint of the primary side 52. Here, "first connection point 5207" can be understood as "the common end of the first primary side segment 521 and the second primary side segment 523" mentioned above. The length of the trace between the first end 5201 of the primary side 52 and the first connection point 5207 (i.e., the first primary side segment 521) is a first length, and the length of the trace between the first end 5201 of the primary side 52 and the midpoint of the primary side 52 (i.e., half of the primary side 52) is a second length. The ratio between the first length and the second length is greater than or equal to 1 / 4 and less than or equal to 1 / 2. For example, the ratio can be 1 / 4, 1 / 3, 1 / 2, etc. Therefore, in this embodiment, the first connection point 5207 is located on the original side 52, relatively close to the first end 5201, which can avoid causing a large offset to the imaginary part of the balun input impedance.

[0111] Similarly, the fourth inductor 340 is connected to the second connection point 5209 of the primary side 52. The second connection point 5209 is located between the second end 5203 of the primary side 52 and the midpoint of the primary side 52. Here, "second connection point 5209" can be understood as "the common terminal of the second primary side segment 523 and the third primary side segment 525" mentioned above. The length of the trace between the second end 5203 of the primary side 52 and the second connection point 5209 (i.e., the third primary side segment 525) is the third length, and the length of the trace between the second end 5203 of the primary side 52 and the midpoint of the primary side 52 (i.e., half of the primary side 52) is the fourth length. The ratio between the third length and the fourth length is greater than or equal to 1 / 4 and less than or equal to 1 / 2. For example, the ratio can be 1 / 4, 1 / 3, 1 / 2, etc. Therefore, in this embodiment, the second connection point 5209 is located on the original side 52, relatively close to the second end 5203, which can avoid causing a large offset to the imaginary part of the balun input impedance.

[0112] In some possible embodiments, the trace length (i.e., the first length) between the first end 5201 of the primary side 52 and the first connection point 5207 can be equal to the trace length (i.e., the third length) between the second end 5203 of the primary side 52 and the second connection point 5209, in order to ensure the balance of a pair of radio frequency differential signal transmissions.

[0113] Since the matching unit 30 in this embodiment can reuse part of the inductance of the primary side of the balun (that is, the equivalent inductance of the first primary side segment 521 and the third primary side segment 525), therefore, compared to Figure 5 In the illustrated embodiment, to achieve the same impedance matching, the inductance values ​​of the third inductor 330 and the fourth inductor 340 can be smaller than the inductance values ​​of the first inductor 310 and the second inductor 320, thereby reducing the layout space occupied by the third inductor 330 and the fourth inductor 340. Specifically, the inductance value of the third inductor 330 is greater than or equal to 0.3nH and less than or equal to 0.6nH. For example, the inductance value of the third inductor 330 can be 0.3nH, 0.4nH, 0.5nH, 0.6nH, etc. The inductance value of the fourth inductor 340 is greater than or equal to 0.3nH and less than or equal to 0.6nH. For example, the inductance value of the fourth inductor 340 can be 0.3nH, 0.4nH, 0.5nH, 0.6nH, etc.

[0114] In some possible embodiments, the inductance value of the third inductor 330 is equal to the inductance value of the fourth inductor 340 to ensure the balance of a pair of radio frequency differential signal transmissions.

[0115] Please see Figure 9 and Figure 10 , Figure 9 and Figure 10 All of these are for the inventors of this application. Figure 8The simulation results for the circuit structure shown are as follows. The inductance values ​​of the third inductor 330 and the fourth inductor 340 are equal. Specifically, Figure 9 The diagram shows the input impedance curves of the balun 50. The left graph shows the real part of the balun's input impedance when the inductance values ​​of the third inductor 330 are 0nH, 0.3nH, and 0.6nH; the right graph shows the imaginary part of the balun's input impedance when the inductance values ​​of the third inductor 330 are 0nH, 0.3nH, and 0.6nH. Figure 9 It is easy to see that when the inductance values ​​of the third inductor 330 are 0nH, 0.3nH, and 0.6nH, the imaginary part of the balun input impedance varies within the range of -0.5 ohms to 1 ohm, and the differences between the three are not significant. However, the real part of the balun input impedance increases as the inductance value of the third inductor 330 increases.

[0116] Specifically, when the inductance of the third inductor 330 is 0nH, the real part of the impedance is between 4.7 ohms and 6 ohms, and the imaginary part is between -0.2 ohms and 1 ohm. When the inductance of the third inductor 330 is 0.3nH, the real part of the impedance is between 10.7 ohms and 12.5 ohms, and the imaginary part is between -0.2 ohms and 0.4 ohms. When the inductance of the third inductor 330 is 0.6nH, the real part of the impedance is between 17.9 ohms and 20.7 ohms, and the imaginary part is between -0.4 ohms and 0.5 ohms.

[0117] Here we combine Figure 6 It is not difficult to see that when the real part of the balun input impedance is approximately 18 to 21 ohms, the inductance of the first inductor 310 is 1 nH, while the inductance of the third inductor 330 is 0.6 nH. Therefore, compared to Figure 5 The first inductor 310 and the second inductor 320 in the illustrated embodiment, Figure 8 The embodiment shown reuses part of the inductance of the primary side of the balun, which reduces the inductance of the third inductor 330 and the fourth inductor 340 to achieve the same balun input impedance, thereby reducing the hardware cost of the power amplifier 100.

[0118] Figure 10 The diagram shows the Smith charts for the balun input impedance when the inductance values ​​of the third inductor 330 are 0nH, 0.3nH, and 0.6nH. From... Figure 10 It is easy to see that as the inductance value of the third inductor 330 increases, the Smith curve corresponding to the balun input impedance is closer to the center of the circle.

[0119] exist Figure 8In the illustrated embodiment, the power amplifier circuit 10 is integrated into the first chip 12, for example, the first chip 12 may be an HBT chip. The first chip 12 and the balun 50 are adapted to be disposed on a substrate (not shown in the figure). For example, the first chip 12 can be fixed on the substrate by a flip-chip process or a wire bonding process, and the balun 50 can be wound on the substrate by metal traces.

[0120] In some possible embodiments, the first primary segment 521 and the third primary segment 525 can be symmetrically disposed on the substrate to ensure the balance of a pair of radio frequency differential signal transmissions.

[0121] In some possible embodiments, the third inductor 330 is a third connector 107 connected between the first chip 12 and the substrate, the third connector 107 being used to connect the first output terminal 104 to the common terminal of the first primary segment 521 and the second primary segment 523. The fourth inductor 340 is a fourth connector 109 connected between the first chip 12 and the substrate, the fourth connector 109 being used to connect the second output terminal 106 to the common terminal of the second primary segment 523 and the third primary segment 525.

[0122] Since the inductance of the third inductor 330 and the fourth inductor 340 is relatively small, they can be equivalently connected by connectors between the first chip 12 and the substrate, respectively. Therefore, no additional inductors are required, saving layout space on the substrate. In one embodiment, the first chip 12 is fixed to the substrate using a wire bonding process, in which case the third connector 107 and the fourth connector 109 are bonding wires. Specifically, the bonding wires can be metal wires such as copper or silver wires. In another embodiment, the first chip 12 is fixed to the substrate using an over-mount process, in which case the third connector 107 and the fourth connector 109 are bumps. Specifically, the bumps can be columnar or spherical, and the material used can be copper or tin. For example, the bumps can be copper columnar or tin ball.

[0123] Furthermore, since the third inductor 330 and the fourth inductor 340 can be equivalent to the third connector 107 and the fourth connector 109 respectively, the matching capacitor 350 can be integrated into the first chip 12 to save layout space on the substrate.

[0124] In some possible embodiments, the third connector 107 can be used to replace a portion of the inductance of the third inductor 330, and the other portion of the inductance of the third inductor 330 can be implemented by the first metal connecting wire. This first metal connecting wire is used to connect the third connector 107 to the common terminal of the first primary segment 521 and the second primary segment 523. Specifically, the first metal connecting wire can be a metal trace or a metal jumper.

[0125] Similarly, the fourth connector 109 can be used to replace a portion of the inductance of the fourth inductor 340, and the remaining portion of the inductance of the fourth inductor 340 can be implemented by the second metal connecting wire. This second metal connecting wire is used to connect the fourth connector 109 to the common terminal of the second primary segment 523 and the third primary segment 525. Specifically, the second metal connecting wire can be a metal trace or a metal jumper.

[0126] In some possible embodiments, the power amplifier circuit 10 is integrated into the first chip 12, and the first chip 12 and the balun 50 are adapted to be disposed on the substrate. As one implementation, the third inductor 330 and the fourth inductor 340 are disposed on the substrate in the form of metal traces. Specifically, the inductance of the third inductor 330 and the fourth inductor 340 can be adjusted by adjusting the length of the metal traces. As another implementation, the third inductor 330 and the fourth inductor 340 are disposed on the substrate as surface mount devices to make the substrate layout more compact and reasonable.

[0127] This application embodiment also provides a power amplifier device 300, which is mainly used to amplify the power of the input radio frequency signal. It may include a push-pull power amplifier, a balanced power amplifier, a Doherty power amplifier, etc.

[0128] Please see Figure 11 The power amplification device 300 may include an envelope tracking power supply 210 and the aforementioned power amplifier 100. The power amplifier 100 may include a power amplification circuit 10, a matching unit 30, and a balun 50. The power amplification circuit 10 has a power supply terminal 102, a first output terminal 104, and a second output terminal 106. The power supply terminal 102 is connected to the envelope tracking power supply 210. For a detailed description of the envelope tracking power supply 210, please refer to the relevant content in the above embodiments. The first output terminal 104 and the second output terminal 106 are used to output a pair of radio frequency differential signals.

[0129] In this embodiment, the balun 50 may include a coupled primary side 52 and a secondary side 54. A matching unit 30 is connected between the first output terminal 104, the second output terminal 106, and the primary side 52. It is used to increase the input impedance of the balun 50 so that the output power of the power amplifier 100 is less than or equal to the maximum transmit power corresponding to a preset power level. For a detailed description of the "maximum transmit power corresponding to the preset power level," please refer to the relevant content in the above embodiment.

[0130] Since the impedance of the balun 50 is typically low, this embodiment uses a matching unit 30 between the balun 50 and the power amplifier circuit 10 to increase the input impedance of the balun 50 without changing its bandwidth and turns ratio, thereby reducing the actual output power of the power amplifier 100. Even when the supply voltage of the power amplifier circuit 10 is high, the actual output power of the power amplifier 100 can still meet the power level specified for different power levels (i.e., less than or equal to the maximum transmit power specified for different power levels), ensuring that the RF front-end module equipped with the power amplifier 100 can operate normally.

[0131] Specifically, for details regarding the power amplifier circuit 10, the matching unit 30, and the balun 50, please refer to the relevant content in the above embodiments, which will not be repeated here.

[0132] This application embodiment also provides a radio frequency front-end module 400, which is a component that integrates two or more discrete devices such as radio frequency switches, low noise amplifiers, filters, duplexers, and power amplifiers into an independent module, thereby improving integration and hardware performance, and miniaturizing the size.

[0133] Please see Figure 12 The RF front-end module 400 may include a substrate 410, a balun 50, and a first chip 12. The balun 50 is disposed on the substrate 410 and may include a primary side 52 and a secondary side 54 coupled together. The first chip 12 is disposed on the substrate 410 and contains a power amplifier circuit 10 and a matching unit 30. Specifically, the substrate 410 is generally rectangular and serves to fix and support the components (e.g., the balun 50, the first chip 12, etc.) in the RF front-end module 400. Specifically, the substrate 410 may be a copper-clad laminate. By performing hole processing, chemical copper plating, electroplating, etching, and other processes on the copper-clad laminate, circuits can be printed on the surface of the substrate 410.

[0134] The power amplifier circuit 10 has a power supply terminal 102, a first output terminal 104, and a second output terminal 106. The power supply terminal 102 is used to connect to the power module 200, and the power supply voltage output by the power module to the power amplifier circuit 10 is greater than a preset voltage threshold. For example, the power module 200 can be an envelope tracking (ET) power supply or an average power tracking (APT) power supply. For a detailed description of the power module 200, please refer to the relevant content in the above embodiments. The first output terminal 104 and the second output terminal 106 are used to output a pair of radio frequency differential signals.

[0135] Matching unit 30 is connected between the first output terminal 104, the second output terminal 106, and the primary side 52. It is used to increase the input impedance of the balun 50 so that the output power of the power amplifier 100 is less than or equal to the maximum transmit power corresponding to a preset power level. For a detailed description of the "maximum transmit power corresponding to the preset power level," please refer to the relevant content in the above embodiment.

[0136] Since the impedance of the balun 50 is typically low, this embodiment uses a matching unit 30 between the balun 50 and the power amplifier circuit 10 to increase the input impedance of the balun 50 without changing its bandwidth and turns ratio, thereby reducing the actual output power of the power amplifier 100. Even when the supply voltage of the power amplifier circuit 10 is high, the actual output power of the power amplifier 100 can still meet the power level specified for different power levels (i.e., less than or equal to the maximum transmit power specified for different power levels), ensuring that the RF front-end module 400 equipped with the power amplifier 100 can operate normally.

[0137] For a detailed description of the power amplifier circuit 10 and the balun 50, please refer to the relevant content in the above embodiments, which will not be repeated here.

[0138] In some possible embodiments, the matching unit 30 may include a first inductor 310 and a second inductor 320. The first inductor 310 is connected between the first output terminal 104 and the first end of the primary side 52, and the second inductor 320 is connected between the second output terminal 106 and the second end 5203 of the primary side 52. Specifically, the specific implementation of the first inductor 310 and the second inductor 320 can be referred to the relevant description in the embodiments above, and will not be repeated here.

[0139] In some possible embodiments, both the first inductor 310 and the second inductor 320 are adjustable inductors. The inductance values ​​of the first inductor 310 and the second inductor 320 can be dynamically adjusted according to the output power of the RF front-end module equipped with the power amplifier 100, so that the output power of the RF front-end module 400 is maintained within a normal power range.

[0140] Please see Figure 13 and Figure 14The RF front-end module 400 may further include a second chip 14 disposed on the substrate 410. The second chip 14 contains a control unit 140, which adjusts the inductance values ​​of the first inductor 310 and the second inductor 320 according to the output power of the RF front-end module. Optionally, the second chip 14 may be a silicon-on-insulator (SOI) chip, a chip based on PHEMT (pseudo-hybrid high electron mobility transistor) technology, or a chip based on CMOS technology.

[0141] In this embodiment, the inductance value of the first inductor 310 is positively correlated with the output power of the RF front-end module 400, and the inductance value of the second inductor 320 is positively correlated with the output power of the RF front-end module 499. Specifically, the higher the output power of the RF front-end module 400, the larger the inductance values ​​of the first inductor 310 and the second inductor 320, and the larger the input impedance of the balun 50, thereby reducing the output power of the RF front-end module and preventing excessive output power. Conversely, the lower the output power of the RF front-end module 400, the smaller the inductance values ​​of the first inductor 310 and the second inductor 320, and the smaller the input impedance of the balun 50, thereby preventing excessive attenuation of the output power of the RF front-end module and improving the output efficiency of the RF signal.

[0142] Therefore, by adjusting the inductance values ​​of the first inductor 310 and the second inductor 320, this embodiment can maintain the output power of the RF front-end module 400 within a normal power range, thereby ensuring the normal operation of the RF front-end module 400.

[0143] exist Figure 13 In the illustrated embodiment, the first inductor 310 may include M first sub-inductors 3102, where M is an integer greater than 1. For example, M can be equal to 2, 3, 4, 5, etc. The control unit 140 may include N first switches 1401, where N is an integer greater than or equal to 1 and less than or equal to M. For example, when M equals 4, N can be equal to 1, 2, 3, 4.

[0144] M first sub-inductors 3102 are connected in series between the first output terminal 104 and the first terminal 5201 of the primary side 52. N first switches 1401 are connected in parallel with the N first sub-inductors 3102 in a one-to-one correspondence. Specifically, the inductance values ​​of the M first sub-inductors 3102 can be the same or different from each other. The first switches 1401 can be transistor switches, such as HBT transistors, MOSFET transistors, SOI substrate-based field-effect transistors, etc.

[0145] The second inductor 320 may include P second sub-inductors 3201, where P is an integer greater than 1. For example, P can be equal to 2, 3, 4, 5, etc. The control unit 140 may include Q second switches 1403, where Q is an integer greater than or equal to 1 and less than or equal to P. For example, when P equals 4, Q can be equal to 1, 2, 3, 4.

[0146] P second sub-inductors 3201 are connected in series between the second output terminal 106 and the second terminal 5203 of the primary side 52. Q second switches 1403 are connected in parallel with the Q second sub-inductors 3201, one for each. Specifically, the inductance values ​​of the P second sub-inductors 3201 can be the same or different. The second switches 1403 can be transistor switches, such as HBT transistors, MOSFET transistors, SOI substrate-based field-effect transistors, etc.

[0147] exist Figure 14 In the illustrated embodiment, M first sub-inductors 3102 are connected in parallel between the first output terminal 104 and the first terminal 5201 of the primary side 52. N first switches 1401 are connected in series in the branches containing the N first sub-inductors 3102. P second sub-inductors 3201 are connected in parallel between the second output terminal 106 and the second terminal 5203 of the primary side 52. Q second switches 1403 are connected in series in the branches containing the Q second sub-inductors 3201.

[0148] exist Figure 13 and Figure 14 In the illustrated embodiment, the control unit 140 may further include a controller 1405, which is electrically connected to N first switches 1401. The controller 1405 is used to adjust the operating states of the N first switches 1401 based on the output power of the RF front-end module to adjust the equivalent inductance value of the first inductor 310. The operating states include an on state and an off state. The controller 1405 is also electrically connected to Q second switches 1403, and the controller 1405 is also used to adjust the operating states of the Q second switches 1403 based on the output power of the RF front-end module to adjust the equivalent inductance value of the second inductor 320.

[0149] Specifically, the controller 1405 can be a microcontroller unit (MCU). The controller 1405 can obtain the actual output power of the RF front-end module 400, thereby determining the equivalent inductance values ​​of the first inductor 310 and the second inductor 320, and controlling the working state of N first switches 1401 and Q second switches 1403 to achieve dynamic adjustment of the inductance value.

[0150] Therefore, in this embodiment, the controller 1405 controls the operating state of the first switch 1401 corresponding to the first sub-inductor 3102 to control whether the first sub-inductor 3102 is connected to the inductance network corresponding to the first inductor 310, thereby enabling flexible adjustment of the equivalent inductance value of the first inductor 310. Similarly, the controller 1405 controls the operating state of the second switch 1403 corresponding to the second sub-inductor 3201 to control whether the second sub-inductor 3201 is connected to the inductance network corresponding to the second inductor 320, thereby enabling flexible adjustment of the equivalent inductance value of the second inductor 320, so that the first inductor 310 and the second inductor 320 can be considered as adjustable inductors respectively.

[0151] This application provides an RF front-end module 400, which may include a substrate 410, a balun 50, and a first chip 12. The first chip 12 houses a power amplifier circuit 10 and a matching unit 30. The power amplifier circuit 10 has a power supply terminal 102, a first output terminal 104, and a second output terminal 106. The power supply terminal 102 is used to connect to a power module 200, for example, the power module 200 may be an envelope tracking (ET) power supply or an average power tracking (APT) power supply. The first output terminal 104 and the second output terminal 106 are used to output a pair of RF differential signals. In other words, the power amplifier circuit 10 in this application adopts a differential structure.

[0152] Since the impedance of the balun 50 is usually low, this application provides a matching unit 30 between the balun 50 and the power amplifier circuit 10. The matching unit 30 can increase the input impedance of the balun 50 to reduce the output power of the power amplifier, thereby enabling the actual output power of the power amplifier to meet the power level specified by different power levels (that is, less than or equal to the maximum transmit power specified by different power levels), so as to ensure that the RF front-end module 400 can work normally.

[0153] Please see Figure 15 This embodiment also provides an electronic device 500, which can be a 4G or 5G communication device such as a smartphone, tablet, or smartwatch. Specifically, the electronic device 500 may include the power amplifier 100 in the above embodiment. Alternatively, the electronic device 500 may include the power amplifier device 300 in the above embodiment. Alternatively, the electronic device 500 may include the radio frequency front-end module 400 in the above embodiment to realize the reception and transmission of radio frequency signals. Furthermore, with the development of 5G technology, the performance requirements for radio frequency front-end modules are becoming increasingly higher. The technical solution of this application can be applied to 5G radio frequency front-end modules to improve the communication performance of 5G communication devices.

[0154] It should be noted that, where there is no conflict or contradiction, the embodiments in this specification can be combined with each other. For example, the technical features included in power amplifier 100 can be combined with the embodiments corresponding to power amplifier device 300, and the technical features included in power amplifier 100 can also be combined with the embodiments corresponding to RF front-end module 400; as another example, the technical features of one embodiment corresponding to power amplifier 100 can be combined with another embodiment corresponding to power amplifier 100. Exemplarily, Figure 5 The technical features of the power amplifier 100 shown can be compared with... Figure 1 or Figure 2 The technical features of the power amplifier 100 shown are combined with each other. Figure 8 The technical features of the power amplifier 100 shown can be compared with... Figure 1 or Figure 3 The technical features of the power amplifier 100 shown are combined with each other.

[0155] In this application specification, certain terms are used to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. The specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" throughout the specification and claims is an open-ended term and should be interpreted as "including but not limited to"; "generally" means that those skilled in the art can solve the technical problem within a certain margin of error and basically achieve the technical effect.

[0156] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "inside", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the purpose of simplifying the description of this application and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0157] In this application, unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or merely surface contact. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0158] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0159] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 this application.

Claims

1. A power amplifier, characterized in that, The device includes a power amplifier circuit, a matching unit, and a balun. The balun includes a primary side and a secondary side that are coupled together. The primary side includes a first primary side segment, a second primary side segment, and a third primary side segment. The two ends formed by the first primary side segment, the second primary side segment, and the third primary side segment connected in series are respectively the first end and the second end of the primary side. The balun also includes an input matching capacitor connected between the first end and the second end. The power amplifier circuit has a power supply terminal, a first output terminal and a second output terminal. The power supply terminal is used to connect to a power supply module. The power supply voltage output by the power supply module to the power amplifier circuit is greater than a preset voltage threshold. The first output terminal and the second output terminal are used to output a pair of radio frequency differential signals. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level. The matching unit includes a third inductor, a fourth inductor, and a matching capacitor. One end of the third inductor is connected to the first output terminal, and the other end is connected to the common terminal of the first primary side and the second primary side. One end of the fourth inductor is connected to the second output terminal, and the other end is connected to the common terminal of the second primary side and the third primary side. The matching capacitor is connected between the first output terminal and the second output terminal.

2. The power amplifier according to claim 1, characterized in that, The power module is an envelope tracking power supply or an average power tracking power supply.

3. The power amplifier according to claim 1, characterized in that, The preset voltage threshold is greater than or equal to 3.4V.

4. The power amplifier according to claim 1, characterized in that, The supply voltage is greater than or equal to 3.6V and less than or equal to 4V; or The power supply voltage is greater than or equal to 3.8V and less than or equal to 5.2V.

5. The power amplifier according to claim 1, characterized in that, When the power amplifier operates in the first frequency band, the maximum transmit power corresponding to the preset power level is 26dBm; When the power amplifier operates in the second frequency band, the maximum transmit power corresponding to the preset power level is 23dBm; wherein, the frequency of the first frequency band is higher than the frequency of the second frequency band.

6. The power amplifier according to claim 5, characterized in that, The first frequency band is 3GHz to 6GHz; or / and The second frequency band is 1.5 GHz to 3 GHz; or / and The ratio of the number of turns of the secondary side to the number of turns of the primary side is greater than or equal to 2 and less than or equal to 5.

7. A power amplifier, characterized in that, The device includes a power amplifier circuit, a matching unit, and a balun. The balun includes an input matching capacitor, a coupled primary side, and a secondary side. The primary side includes a first primary side segment, a second primary side segment, and a third primary side segment. The first primary side segment, the second primary side segment, and the third primary side segment are connected in series to form the first and second ends of the primary side, respectively. The input matching capacitor is connected between the first end and the second end. The power amplifier circuit has a power supply terminal, a first output terminal and a second output terminal. The power supply terminal is used to connect to the power supply module, and the first output terminal and the second output terminal are used to output a pair of radio frequency differential signals. The matching unit includes a third inductor, a fourth inductor, and a matching capacitor. One end of the third inductor is connected to the first output terminal, and the other end of the third inductor is connected to the common terminal of the first primary segment and the second primary segment. One end of the fourth inductor is connected to the second output terminal, and the other end of the fourth inductor is connected to the common terminal of the second primary segment and the third primary segment. The matching capacitor is connected between the first output terminal and the second output terminal.

8. The power amplifier according to claim 7, characterized in that, The inductance value of the first primary segment is equal to the inductance value of the third primary segment.

9. The power amplifier according to claim 7, characterized in that, The ratio between the inductance value of the first primary segment and the total inductance value of the primary side is greater than or equal to 1 / 8 and less than or equal to 1 / 4; the ratio between the inductance value of the third primary segment and the total inductance value of the primary side is greater than or equal to 1 / 8 and less than or equal to 1 / 4. Alternatively, the third inductor is connected to the first connection point of the primary side, the first connection point being located between the first end of the primary side and the midpoint of the primary side, the trace length between the first end of the primary side and the first connection point being the first length, the trace length between the first end of the primary side and the midpoint of the primary side being the second length, and the ratio between the first length and the second length being greater than or equal to 1 / 4 and less than or equal to 1 / 2; The fourth inductor is connected to the second connection point of the primary side. The second connection point is located between the second end of the primary side and the midpoint of the primary side. The trace length between the second end of the primary side and the second connection point is the third length. The trace length between the second end of the primary side and the midpoint of the primary side is the fourth length. The ratio between the third length and the fourth length is greater than or equal to 1 / 4 and less than or equal to 1 / 2.

10. The power amplifier according to any one of claims 7 to 9, characterized in that, The inductance value of the third inductor is greater than or equal to 0.3nH and less than or equal to 0.6nH; The inductance value of the fourth inductor is greater than or equal to 0.3nH and less than or equal to 0.6nH.

11. The power amplifier according to any one of claims 7 to 9, characterized in that, The power amplifier circuit is integrated into a first chip, and the first chip and the balun are adapted to be disposed on a substrate. The third inductor is a third connector connected between the first chip and the substrate, and the third connector is used to connect the first output terminal to the common terminal of the first primary segment and the second primary segment; the fourth inductor is a fourth connector connected between the first chip and the substrate, and the fourth connector is used to connect the second output terminal to the common terminal of the second primary segment and the third primary segment. Wherein, the third connector and the fourth connector are bonding wires; or, the third connector and the fourth connector are protrusions.

12. The power amplifier according to any one of claims 7 to 9, characterized in that, The power amplifier circuit is integrated into a first chip, and the first chip and the balun are adapted to be disposed on a substrate. The third inductor and the fourth inductor are disposed on the substrate in the form of metal traces; or, the third inductor and the fourth inductor are disposed on the substrate in the form of surface mount devices.

13. The power amplifier according to any one of claims 7 to 9, characterized in that, The third inductor and the fourth inductor are used to increase the input impedance of the balun so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to the preset power level; Specifically, when the power amplifier operates in the first frequency band, the maximum transmit power corresponding to the preset power level is 26dBm; when the power amplifier operates in the second frequency band, the maximum transmit power corresponding to the preset power level is 23dBm; the frequency of the first frequency band is higher than the frequency of the second frequency band.

14. The power amplifier according to claim 13, characterized in that, The first frequency band is 3GHz to 6GHz; or / and The second frequency band is 1.5 GHz to 3 GHz; or / and The ratio of the number of turns of the secondary side to the number of turns of the primary side is greater than or equal to 2 and less than or equal to 5.

15. A power amplifier device, characterized in that, The device includes an envelope tracking power supply and a power amplifier. The power amplifier includes a power amplification circuit, a matching unit, and a balun. The balun includes a primary side and a secondary side coupled together. The primary side includes a first primary side segment, a second primary side segment, and a third primary side segment. The first, second, and third primary side segments are connected in series to form the first and second ends of the primary side, respectively. The balun also includes an input matching capacitor connected between the first and second ends. The power amplifier circuit has a power supply terminal, a first output terminal and a second output terminal. The power supply terminal is connected to the envelope tracking power supply. The first output terminal and the second output terminal are used to output a pair of radio frequency differential signals. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level. The matching unit includes a third inductor, a fourth inductor, and a matching capacitor. One end of the third inductor is connected to the first output terminal, and the other end is connected to the common terminal of the first primary side and the second primary side. One end of the fourth inductor is connected to the second output terminal, and the other end is connected to the common terminal of the second primary side and the third primary side. The matching capacitor is connected between the first output terminal and the second output terminal.

16. A radio frequency front-end module, characterized in that, include: substrate; A balun is disposed on the substrate. The balun includes a primary side and a secondary side coupled together. The primary side includes a first primary side segment, a second primary side segment, and a third primary side segment. The two ends formed by the first primary side segment, the second primary side segment, and the third primary side segment connected in series are respectively the first end and the second end of the primary side. The balun also includes an input matching capacitor connected between the first end and the second end. as well as A first chip is disposed on the substrate. The first chip contains a power amplifier circuit and a matching unit. The power amplifier circuit has a power supply terminal, a first output terminal and a second output terminal. The power supply terminal is used to connect to a power supply module. The power supply voltage output by the power supply module to the power amplifier circuit is greater than a preset voltage threshold. The first output terminal and the second output terminal are used to output a pair of radio frequency differential signals. The matching unit is connected between the first output terminal, the second output terminal, and the primary side to increase the input impedance of the balun, so that the output power of the power amplifier is less than or equal to the maximum transmit power corresponding to a preset power level. The matching unit includes a third inductor, a fourth inductor, and a matching capacitor. One end of the third inductor is connected to the first output terminal, and the other end is connected to the common terminal of the first primary side and the second primary side. One end of the fourth inductor is connected to the second output terminal, and the other end is connected to the common terminal of the second primary side and the third primary side. The matching capacitor is connected between the first output terminal and the second output terminal.

17. An electronic device, characterized in that, include: The power amplifier as described in any one of claims 1 to 14; Or, the power amplifier device as described in claim 15; Alternatively, the radio frequency front-end module as described in claim 16.

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