Power Amplification Circuits and Radio Frequency Systems

Abstract

The present application discloses a power amplifier circuit and a radio frequency system. The circuit includes a power amplifier unit and a wideband improvement unit. The power amplifier unit includes a signal input port, a signal output port, a power transistor, and a first inductor. The power transistor is configured to perform power amplification for radio frequency signals of multiple frequency bands. The wideband improvement unit adjusts a parallel resonant frequency of the power amplifier unit to reduce an envelope impedance of the power amplifier unit between a first target frequency and a second target frequency. The first target frequency is a maximum frequency difference between the multiple frequency bands, and the second target frequency is a minimum frequency difference between the multiple frequency bands. In the present application, based on not adding an output internal matching circuit, the envelope impedance between the first target frequency and the second target frequency is reduced by the added wideband improvement unit, thereby increasing the video bandwidth of the power amplifier circuit and improving the DPD linearity of the wideband signal.

Description

[Technical field]

[0001] This application relates to the field of radio frequency amplification, and in particular to power amplifier circuits and radio frequency systems. [Background technology]

[0002] As the fifth generation mobile communication technology (5G) is widely used, the signal bandwidth is constantly increasing. The shortage of spectrum and the effective utilization of base station resources also encourage more operators to share base station resources and spectrum. In this way, the base station needs to support a larger signal bandwidth. For example, a signal in the 1.8 GHz frequency band and a signal in the 2.1 GHz frequency band share one base station. Therefore, the power amplifier of the base station needs to support both signals in the two frequency bands of 1.8 GHz and 2.1 GHz. The bandwidth between the two frequency bands (1805 MHz to 2170 MHz) is close to 400 MHz. The existing power amplifier design and the existing digital pre-distortion (DPD) linear design cannot meet the requirements of the wireless communication protocol. In order to improve the linear performance of the DPD correction, the device circuit design of the power amplifier needs to be further optimized and the video bandwidth (VBW) needs to be increased.

[0003] In order to better meet the wideband performance, currently, in the power amplification device for wideband applications, the internal matching design is generally not used inside the output of the device, and the wideband external matching design is used for the external circuit of the device. However, in the external matching design, the high-output power amplification device has large parasitic parameters and small video bandwidth, which cannot meet the requirements of wide bandwidth and related protocols. In view of this, a new radio frequency power amplification circuit needs to be provided to increase the video bandwidth when ensuring the radio frequency performance of the power amplification circuit and improve the linear performance of DPD correction. Summary of the Invention [Means for solving the problem]

[0004] The present application provides a power amplifier circuit and a radio frequency system to increase the video bandwidth and improve the linear performance of DPD correction while ensuring the radio frequency performance of the power amplifier circuit.

[0005] According to a first aspect, the present application provides a power amplifier circuit. The circuit includes a power amplifier unit and a wideband improvement unit. The power amplifier unit includes a signal input port, a signal output port, a power transistor, and a first inductor. A first end of the power transistor is grounded, a second end of the power transistor is connected to the signal input port, a third end of the power transistor is connected to a first end of the first inductor, and a second end of the first inductor is connected to the signal output port. The signal input port is configured to receive radio frequency signals of a plurality of frequency bands. The power transistor is configured to perform power amplification on the radio frequency signals of the plurality of frequency bands. The signal output port is configured to output the radio frequency signals of the plurality of frequency bands on which the power amplification has been performed. The wideband improvement unit is configured to adjust a parallel resonant frequency of the power amplifier unit to reduce an envelope impedance of the power amplifier unit between a first target frequency and a second target frequency. The first target frequency is a maximum frequency difference between the plurality of frequency bands, and the second target frequency is a minimum frequency difference between the plurality of frequency bands.

[0006] In a possible embodiment, the power amplification unit further includes a chip package module, a first end of the power transistor is grounded through the chip package module, a second end of the power transistor is connected to a signal input port through the chip package module, a third end of the power transistor is connected to a first end of a first inductor, a second end of the first inductor is connected to the chip package module, and the first inductor is connected to a signal output port through the chip package module.

[0007] In a possible embodiment, the wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor, one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the second inductor is further connected to one end of the first resistor, the other end of the first resistor is connected to one end of the third inductor, and the other end of the third inductor is connected to the second end of the first inductor.

[0008] According to the power amplifier circuit provided in the present application, on the basis of not adding an output internal matching circuit, a wideband improvement unit is connected inside or outside the chip package module of the power transistor, and the radio frequency capacitor, the second inductor, and the third inductor of the wideband improvement unit generate parallel resonance near the operating frequency band to form a high impedance. In this way, the wideband improvement unit becomes high impedance when operating at a high frequency. The envelope impedance between the first target frequency and the second target frequency is reduced without affecting the performance of the power amplifier unit at the operating frequency. The first resistor can suppress the parasitic series resonance formed by the decoupling capacitor and the inductor to form a smooth envelope impedance curve. Adding a wideband improvement unit can ensure the radio frequency performance and reduce the envelope impedance, which increases the video bandwidth of the power amplifier circuit and improves the DPD linearity of the wideband signal.

[0009] In a possible embodiment, the wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor, one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the first resistor is further connected to one end of the third inductor, and the other end of the third inductor is connected to the second end of the first inductor.

[0010] In the connection manner of the above two embodiments, the first resistor and the radio frequency capacitor are connected at different positions, the wideband improvement unit is integrally connected to the second end of the first inductor, and the wideband improvement unit is connected outside the chip package module of the power transistor, thus reducing the difficulty in designing the circuit.

[0011] In a possible embodiment, the wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor, one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the second inductor is further connected to one end of the first resistor, the other end of the first resistor is connected to one end of the third inductor, and the other end of the third inductor is connected to the first end of the first inductor.

[0012] In a possible embodiment, the wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor, one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the first resistor is further connected to one end of the third inductor, and the other end of the third inductor is connected to the first end of the first inductor.

[0013] In the connection manners of the above two embodiments, the positions where the first resistor and the radio frequency capacitor are connected are different, and the wideband improvement unit is integrally connected to the first end of the first inductor, in other words, the wideband improvement unit can be implemented inside the chip package module of the power transistor. Therefore, the circuit area of ​​the entire power amplifier circuit is reduced. The above design manner facilitates mass production of the power amplifier circuit.

[0014] In a possible embodiment, the first inductor and / or the third inductor are arranged using wire bonding technology. The third inductor of the wideband improvement unit can be arranged using wire bonding technology. The value of the radio frequency capacitor is at the communication radio frequency pf level, and the value of the decoupling capacitor is at the nf level. The first resistor can be manufactured using a thin film process, and the first resistor and the radio frequency capacitor can be arranged on one device to reduce the area.

[0015] In a possible embodiment, the envelope impedance peak of the power amplifier circuit is at a parallel resonant frequency, and the parallel resonant frequency of the power amplifier circuit satisfies the following equation:

number

[0016] Between the first target frequency and the second target frequency, after the wideband improvement unit is added, the envelope impedance of the power amplification unit is greatly reduced, so that the video bandwidth of the power amplification circuit can be increased and the DPD linear performance can be improved.

[0017] In a possible embodiment, the power amplifier circuit further comprises a power supply, the power supply being configured to supply power to the power transistor.

[0018] According to a second aspect, the present application provides a radio frequency system. The system includes a power source, a radio frequency antenna, and a power amplification circuit as provided in the first aspect. The power source is configured to provide power to the power amplification circuit. The radio frequency antenna is configured to transmit radio frequency signals in multiple frequency bands for which power amplification has been performed.

[0019] These and other aspects of the present application will become clearer and more understandable in the description of the embodiments that follow. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing the structure of a power amplifier circuit in the prior art. [Diagram 2] FIG. 1 is a diagram showing the structure of another power amplifier circuit in the prior art. [Diagram 3] FIG. 1 is a diagram of the structure of a power amplifier circuit according to the present application. [Figure 4] FIG. 2 is a first diagram of the structure of a power amplification unit according to the present application; [Diagram 5] FIG. 2 is a second diagram of the structure of a power amplification unit according to the present application. [Figure 6A] FIG. 2 is a first diagram of a specific structure of a power amplifier circuit according to the present application; [Figure 6B] FIG. 2 is a second diagram of a specific structure of a power amplifier circuit according to the present application. [Figure 7] FIG. 2 is a first curve diagram of envelope impedance varying with frequency according to the present application. [Figure 8A] FIG. 3 is a third diagram of a specific structure of a power amplifier circuit according to the present application. [Figure 8B] FIG. 4 is a fourth diagram of a specific structure of a power amplifier circuit according to the present application. [Figure 9] FIG. 4 is a second curve diagram of envelope impedance varying with frequency according to the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The following clearly and fully describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. It is clear that the described embodiments are only a part, not all, of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall be within the protection scope of the present application.

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the following will further describe the present application in detail with reference to the accompanying drawings. A specific operation method in the method embodiment may also be applied to the device embodiment or the system embodiment. It should be noted that in the description of the present application, "at least one" means one or more, and "multiple" means two or more. In view of this, in the embodiment of the present invention, "multiple" may also be understood as "at least two". The term "and / or" describes an association relationship for describing associated objects, and represents that three relationships may exist. For example, A and / or B may represent the following three cases, namely, only A exists, both A and B exist, and only B exists. In addition, unless otherwise specified, the symbol " / " generally indicates an "or" relationship between associated objects. In addition, it should be understood that in the description of the present application, terms such as "first" and "second" are only used for distinction and explanation, and should not be understood as indicating or implying relative importance, or as indicating or implying order.

[0023] In the embodiment of the present application, it should be noted that "connection" means electrical connection, and the connection between two electrical elements may be a direct or indirect connection between the two electrical elements. For example, the connection between A and B may be a direct connection between A and B, or an indirect connection between A and B via one or more other electrical elements. For example, A being connected to B may also mean that A is directly connected to C, C is directly connected to B, and A and B are connected via C.

[0024] In addition, in this application, unless otherwise expressly specified and defined, terms such as "connect", "connection" and "dispose" should be understood broadly. For example, a connection may be a fixed connection, a detachable connection, or an integral connection, or a connection may be a mechanical connection or an electrical connection, or a connection may be a direct connection, an indirect connection through an intermediate medium, or an internal communication or an interaction relationship between two components. Those skilled in the art may understand the specific meaning of the terms in the present invention based on the specific situation.

[0025] With the update of wireless technology, data transmission capability is greatly improved, and signal bandwidth is expanded accordingly. To meet the increasing user data requirements, expanding the signal bandwidth is the most effective way. However, the shortage of spectrum and the effective utilization of base station resources encourage more operators to share base station resources and spectrum. In this way, the base station needs to support a large signal bandwidth. For example, a signal in the 1.8 GHz frequency band and a signal in the 2.1 GHz frequency band share one base station. Therefore, the power amplifier circuit of the base station needs to support performing power amplification for the signals of both the two frequency bands (1.8 GHz and 2.1 GHz). However, the bandwidth between the frequency bands (1805 MHz to 2170 MHz) is close to 400 MHz. Therefore, the power amplifier circuit needs to be designed for a wide bandwidth.

[0026] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the prior art is first described.

[0027] In order to better meet the wideband performance of the power amplifier circuit, as shown in the structure of the power amplifier circuit in the prior art in FIG. 1, generally, no internal matching is used inside the output of the power amplifier circuit, and a wideband external matching design is used for the external circuit of the power amplifier circuit. In order to increase the video bandwidth of the power amplifier circuit, at least one of the following methods may be used: reducing the parasitic capacitance inside the power amplifier device, reducing the inductance between the power amplifier device and the external package, and reducing the parasitic capacitance and parasitic inductance of the external package. Optionally, a power supply bias circuit may be added outside the power amplifier circuit to increase the video bandwidth of the power amplifier circuit. See FIG. 1. When the parasitic capacitance inside the power amplifier device, the inductance between the power amplifier device and the external package, the parasitic capacitance and parasitic inductance of the external package are all fixed values, the video bandwidth of the power amplifier circuit is increased by adjusting the inductance from the power supply end to the signal output end of the power supply bias circuit. In order to avoid affecting the impedance and radio frequency performance of the power amplifier circuit, the inductance from the power supply end to the signal output end of the power supply bias circuit is generally large. The inductance between the power amplifier device and the external package and the parasitic inductance of the external package are smaller than the inductance from the power end to the signal output end of the power bias circuit. Therefore, the resonant frequency corresponding to the envelope impedance peak of the power amplifier circuit to which the power bias circuit is added can be determined by the inductance from the power end to the signal output end of the power bias circuit. However, the inductance from the power end to the signal output end of the power bias circuit is generally large, so that the optimization effect of the video bandwidth is limited, and the current requirement for increasing the video bandwidth cannot be met.

[0028] FIG. 2 is a diagram of the structure of another power amplifier circuit in the prior art. As shown in FIG. 2, in order to ensure that the current requirements for increasing the video bandwidth are met, multiple low output power amplifier devices are combined in a peripheral coupling manner to be used as a high output power amplifier device. However, when multiple low output power amplifier devices are combined as a high output power amplifier device, the layout area of ​​the multiple low output power amplifier devices becomes large, and the process of combining multiple low output power amplifier devices creates a problem of coupling loss. Therefore, under the trend of low cost and miniaturization of modules, the power amplifier circuit of this structure is gradually being phased out.

[0029] In order to solve the above problems in the prior art, the present application provides a power amplifier circuit. A new wideband improvement unit is used to increase the video bandwidth when ensuring the radio frequency performance of the power amplifier circuit, and improve the linear performance of DPD correction.

[0030] 3 is a diagram of the structure of a power amplifier circuit according to an embodiment of the present application. The power amplifier circuit 300 provided in this embodiment includes a power amplifier unit 301 and a wideband improvement unit 302.

[0031] The power amplification unit 301 is configured to perform power amplification on radio frequency signals of multiple frequency bands. Radio frequency signals are high frequency electromagnetic waves with long distance transmission capability.

[0032] The wideband improving unit 302 is configured to adjust a parallel resonant frequency of the power amplifying unit 301 to reduce an envelope impedance of the power amplifying unit 301 between a first target frequency and a second target frequency, the first target frequency being a maximum frequency difference between the multiple frequency bands, and the second target frequency being a minimum frequency difference between the multiple frequency bands.

[0033] It should be noted that the multiple frequency bands may include at least two frequency bands. For example, the multiple frequency bands include two frequency band signals. When the frequency band signal (1805MHz-1880MHz) and the frequency band signal (2110MHz-2170MHz) share one base station, the first target frequency is 365MHz (2170MHz-1805MHz) and the second target frequency is 230MHz (2110MHz-1880MHz).

[0034] The power amplifier circuit 300 provided in this embodiment of the present application can be used in radio frequency power components incorporated in wireless communication devices such as base stations, for example, radio frequency processing devices or circuits that perform radio signal power amplification, for example, radio frequency filters, antennas, radio frequency small signal boards, repeaters, frequency conversion circuits, or modulators. In a mobile communication system, user data to be transmitted is modulated into a radio frequency signal at the radio frequency front end of a base station or a user terminal, and the radio frequency signal is amplified through the power amplifier circuit of the present application, and then transmitted in space to another base station or a user terminal through an antenna.

[0035] The power amplification unit 301 may include a power amplification device configured to perform power amplification and a controller. The power amplification device may be one or more of multiple types of switch devices, such as metal oxide semiconductor field effect transistor (MOSFET), bipolar junction transistor (BJT), insulated gate bipolar transistor (IGBT), field effect transistor (FET), laterally-diffused metal-oxide semiconductor (LDMOS), silicon carbide (SiC), gallium nitride (GaN), and gallium arsenide (GaAs), which are not listed one by one in the embodiments of the present application. Each of the aforementioned power amplification devices may include a first electrode (source), a second electrode (drain), and a control electrode (gate). The controller controls the connection or disconnection of the power amplification device through the control electrode to perform power amplification of the radio frequency signal. The parasitic parameters of the power amplification device are large, so the video bandwidth is small.

[0036] The envelope impedance (or called baseband impedance) of the power amplification unit 301 directly affects indicators such as linearity, power, and efficiency during the amplification of radio frequency signals. Therefore, under the same conditions, as the envelope impedance of the power amplification unit 301 increases, the output power, efficiency, and gain of the power amplification unit 301 will decrease to a certain degree. Therefore, in order to enable the power amplification unit 301 of the base station to support a larger signal bandwidth, the envelope impedance of the power amplification unit 301 between the first target frequency and the second target frequency needs to be reduced so as to increase the video bandwidth of the power amplification unit 301 when ensuring the radio frequency performance of the power amplification unit 301.

[0037] For possible implementations, please refer to Fig. 4. The power amplifier unit 301 includes a signal input port 3011, a signal output port 3012, a power transistor 3013, and a first inductor 3014. The following describes the connection relationships between devices in the power amplifier unit 301 with reference to Fig. 4.

[0038] A first end of the power transistor 3013 is grounded, a second end of the power transistor 3013 is connected to a signal input port 3011, a third end of the power transistor 3013 is connected to a first end of the first inductor 3014, and a second end of the first inductor 3014 is connected to a signal output port 3012.

[0039] The signal input port 3011 is configured to receive radio frequency signals of multiple frequency bands. The power transistor 3013 is configured to perform power amplification on the radio frequency signals of multiple frequency bands. The signal output port 3012 is configured to output the radio frequency signals of multiple frequency bands that have been power amplified.

[0040] The first inductor 3014 of the power amplification unit 301 may be connected between the power transistor 3013 and the signal output port 3012 using wire bonding technology (metal bonding wire) or a short microstrip. The signal input port 3011, the signal output port 3012, the power transistor 3013, and the first inductor 3014 of the power amplification unit 301 may be disposed on the same substrate, and the transmission line and the radio frequency ground are disposed on the substrate.

[0041] In a possible embodiment, the power amplifier circuit 300 further includes an input matching circuit and an output matching circuit. The input matching circuit is configured to match a first impedance of the signal input port 3011 with a second impedance input by the power transistor 3013. The output matching circuit is configured to match a third impedance output by the power transistor 3013 with a fourth impedance of the signal output port. The signal input port may be connected to the power transistor 3013 via the input matching circuit. The power transistor 3013 is connected to the signal output port 3012 via the output matching circuit.

[0042] In a possible embodiment, the power amplification unit 301 further includes a power supply. The power supply is configured to supply power to the power transistor 3013.

[0043] For possible implementations, please refer to Fig. 5. The power amplification unit 301 further includes a chip package module 3015. A first end of the power transistor 3013 is grounded through the chip package module 3015, a second end of the power transistor 3013 is connected to a signal input port through the chip package module 3015, a third end of the power transistor 3013 is connected to a first end of a first inductor 3014, a second end of the first inductor 3014 is connected to the chip package module 3015, and the first inductor 3014 is connected to a signal output port 3012 through the chip package module 3015. The first inductor 3014 of the power amplification unit 301 may be connected between the power transistor 3013 and the chip package module 3015 using wire bonding technology.

[0044] The wideband improvement unit 302 may include a resistor, an inductor, and a capacitor. The capacitor and the inductor of the wideband improvement unit 302 may generate a parallel resonance at the operating frequency of the power amplification unit 301, so that the wideband improvement unit 302 becomes high impedance and the radio frequency performance of the power amplification unit 301 is not affected. In addition, the resistor of the wideband improvement unit 302 can suppress the parasitic series impedance formed by the capacitor and the inductor to form a smooth envelope impedance curve.

[0045] The wideband improving unit 302 can have several different structures, and the wideband improving unit 302 can be connected to the power amplifying unit 301. All the structures can achieve the function of increasing the video bandwidth and improving the linear performance of the DPD correction while ensuring the radio frequency performance of the power amplifying unit 301.

[0046] Structure 1: see FIG. 6A. The wideband improvement unit 302 may include a decoupling capacitor 3021, a radio frequency capacitor 3022, a second inductor 3023, a third inductor 3024, and a first resistor 3025. One end of the decoupling capacitor 3021 is grounded, the other end of the decoupling capacitor 3021 is connected to one end of the second inductor 3023, the other end of the second inductor 3023 is connected to one end of the radio frequency capacitor 3022, the other end of the radio frequency capacitor 3022 is grounded, the other end of the second inductor 3023 is further connected to one end of the first resistor 3025, the other end of the first resistor 3025 is connected to one end of the third inductor 3024, and the other end of the third inductor 3024 is connected to the second end of the first inductor 3014.

[0047] Structure 2: see FIG. 6B. The wideband improvement unit 302 may include a decoupling capacitor 3021, a radio frequency capacitor 3022, a second inductor 3023, a third inductor 3024, and a first resistor 3025. One end of the decoupling capacitor 3021 is grounded, the other end of the decoupling capacitor 3021 is connected to one end of the second inductor 3023, the other end of the second inductor 3023 is connected to one end of the first resistor 3025, the other end of the first resistor 3025 is connected to one end of the radio frequency capacitor 3022, the other end of the radio frequency capacitor 3022 is grounded, the other end of the first resistor 3025 is further connected to one end of the third inductor 3024, and the other end of the third inductor 3024 is connected to the second end of the first inductor 3014.

[0048] The difference between Structure 1 and Structure 2 is that the positions where the first resistor 3025 and the radio frequency capacitor 3022 are connected are different. The common point between Structure 1 and Structure 2 is that the wideband improvement unit 302 is integrally connected to the second end of the first inductor 3014. In other words, this may represent that the wideband improvement unit 302 is connected outside the chip package module 3015 of the power transistor 3013. Therefore, the difficulty in designing the circuit is reduced.

[0049] At the output pin of the power transistor 3013, a curve diagram of the envelope impedance changing with frequency can be obtained by testing. The envelope impedance peak of the power amplifier circuit 300 is at the parallel resonant frequency. The parallel resonant frequency of the power amplifier circuit 300 satisfies the following equation:

number

[0050] 7 is a curve diagram of the envelope impedance, in which the dashed line shows the envelope impedance test result obtained when the wideband improvement unit 302 is not initially connected, and the solid line shows the envelope impedance test result obtained after the wideband improvement unit 302 is connected.

[0051] Take an example where the first target frequency is 400MHz and the second target frequency is 200MHz. It can be seen from Fig. 7 that between the first target frequency and the second target frequency, after the wideband improvement unit 302 is connected, the envelope impedance is greatly reduced, so that the video bandwidth of the power amplifier circuit 300 can be increased and the DPD linear performance can be improved.

[0052] Structure 3: see FIG. 8A. The wideband improvement unit 302 may include a decoupling capacitor 3021, a radio frequency capacitor 3022, a second inductor 3023, a third inductor 3024, and a first resistor 3025. One end of the decoupling capacitor 3021 is grounded, the other end of the decoupling capacitor 3021 is connected to one end of the second inductor 3023, the other end of the second inductor 3023 is connected to one end of the radio frequency capacitor 3022, the other end of the radio frequency capacitor 3022 is grounded, the other end of the second inductor 3023 is further connected to one end of the first resistor 3025, the other end of the first resistor 3025 is connected to one end of the third inductor 3024, and the other end of the third inductor 3024 is connected to the first end of the first inductor 3014.

[0053] Structure 4: see FIG. 8B. The wideband improvement unit 302 may include a decoupling capacitor 3021, a radio frequency capacitor 3022, a second inductor 3023, a third inductor 3024, and a first resistor 3025. One end of the decoupling capacitor 3021 is grounded, the other end of the decoupling capacitor 3021 is connected to one end of the second inductor 3023, the other end of the second inductor 3023 is connected to one end of the first resistor 3025, the other end of the first resistor 3025 is connected to one end of the radio frequency capacitor 3022, the other end of the radio frequency capacitor 3022 is grounded, the other end of the first resistor 3025 is further connected to one end of the third inductor 3024, and the other end of the third inductor 3024 is connected to the first end of the first inductor 3014.

[0054] The difference between Structure 3 and Structure 4 is that the positions where the first resistor 3025 and the radio frequency capacitor 3022 are connected are different. The common point between Structure 1 and Structure 2 is that the wideband improvement unit 302 is integrally connected to the first end of the first inductor 3014. This may represent that the wideband improvement unit 302 is connected inside the chip package module 3015 of the power transistor 3013. In other words, the wideband improvement unit 302 can be implemented inside the package of the power transistor 3013. Therefore, the circuit area of ​​the entire power amplifier circuit 300 is reduced. The above-mentioned design scheme facilitates mass production of the power amplifier circuit 300.

[0055] At the output pin of the power transistor 3013, a curve diagram of the envelope impedance changing with frequency can be obtained by testing. The envelope impedance peak of the power amplifier circuit 300 is at the parallel resonant frequency. The parallel resonant frequency of the power amplifier circuit 300 satisfies the following equation:

number

[0056] 9 is another curve diagram of the envelope impedance, in which the dashed line shows the envelope impedance test result obtained when the wideband improvement unit 302 is not initially connected, and the solid line shows the envelope impedance test result obtained after the wideband improvement unit 302 is connected.

[0057] Continue to use the example that the first target frequency is 400MHz and the second target frequency is 200MHz. It can be seen from Fig. 9 that between the first target frequency and the second target frequency, after the wideband improvement unit 302 is connected, the envelope impedance is also greatly reduced, so that the video bandwidth of the power amplifier circuit 300 can be increased and the DPD linear performance can be improved.

[0058] The third inductor 3024 of the wideband improvement unit 302 can also be arranged using wire bonding technology (metal bonding wire) or short microstrip. The value of the radio frequency capacitor 3022 is at the communication radio frequency pf level, and the value of the decoupling capacitor is at the nf level. The first resistor 3025 can be manufactured using a thin film process, and the first resistor 3025 and the radio frequency capacitor 3022 can be arranged on one device to reduce the area.

[0059] In the power amplifier circuit provided in this embodiment of the present application, on the basis of not adding an output internal matching circuit, the wideband improvement unit is connected inside or outside the chip package module of the power transistor. The radio frequency capacitor, the second inductor, and the third inductor of the wideband improvement unit generate parallel resonance near the operating frequency band to form a high impedance. In this way, the wideband improvement unit becomes high impedance when operating at a high frequency. Therefore, the envelope impedance between the first target frequency and the second target frequency is reduced without affecting the performance of the power amplifier unit at the operating frequency. The first resistor can suppress the parasitic series resonance formed by the decoupling capacitor and the inductor to form a smooth envelope impedance curve. Adding the wideband improvement unit can ensure the radio frequency performance and reduce the envelope impedance, which increases the video bandwidth of the power amplifier circuit and improves the DPD linearity of the wideband signal.

[0060] Based on the same concept, the present application further provides a radio frequency system, which includes a power source, a radio frequency antenna, and a power amplifier circuit 300 described in the previous embodiment. The power source is configured to supply power to the power amplifier circuit 300. The radio frequency antenna is configured to transmit radio frequency signals of multiple frequency bands in which power amplification has been performed.

[0061] Although the embodiments of the present application have been described, those skilled in the art can make other changes and modifications to these embodiments once the basic inventive concept is known. Therefore, the following claims are intended to be interpreted as including the preferred embodiments and any changes and modifications that are within the scope of the present application.

[0062] It is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the scope of the embodiments of the present application. In this case, if these modifications and variations of the embodiments of the present application are within the scope of protection defined by the following claims and their equivalent technologies, the present application is intended to cover these modifications and variations of the embodiments of the present application. [Explanation of symbols]

[0063] 300 Power Amplifier Circuit 301 Power Amplification Unit 302 Broadband Improvement Unit 3011 Signal input port 3012 Signal output port 3013 Power Transistor 3014 First inductor 3015 Chip Package Module 3021 Decoupling capacitor 3022 Radio Frequency Capacitor 3023 Second Inductor 3024 3rd inductor 3025 First Resistance

Claims

1. A power amplifier circuit, the circuit comprising: a power amplifier unit and a wideband improvement unit; the power amplification unit comprises a signal input port, a signal output port, a power transistor, and a first inductor, a first end of the power transistor is grounded, a second end of the power transistor is connected to the signal input port, a third end of the power transistor is connected to a first end of the first inductor, and a second end of the first inductor is connected to the signal output port; the signal input port is configured to receive radio frequency signals of a plurality of frequency bands, the power transistor is configured to perform power amplification on the radio frequency signals of the plurality of frequency bands, and the signal output port is configured to output the radio frequency signals of the plurality of frequency bands after power amplification; A power amplification circuit, wherein the wideband improvement unit is configured to adjust a parallel resonant frequency of the power amplification unit to reduce an envelope impedance of the power amplification unit between a first target frequency and a second target frequency, the first target frequency being a maximum frequency difference between the multiple frequency bands, and the second target frequency being a minimum frequency difference between the multiple frequency bands.

2. The wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor; 2. The circuit of claim 1, wherein one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the second inductor is further connected to one end of the first resistor, the other end of the first resistor is connected to one end of the third inductor, and the other end of the third inductor is connected to the second end of the first inductor.

3. The wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor; 2. The circuit of claim 1, wherein one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the first resistor is further connected to one end of the third inductor, and the other end of the third inductor is connected to the second end of the first inductor.

4. The wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor; 2. The circuit of claim 1, wherein one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the second inductor is further connected to one end of the first resistor, the other end of the first resistor is connected to one end of the third inductor, and the other end of the third inductor is connected to the first end of the first inductor.

5. The wideband improvement unit includes a decoupling capacitor, a radio frequency capacitor, a second inductor, a third inductor, and a first resistor; 2. The circuit of claim 1, wherein one end of the decoupling capacitor is grounded, the other end of the decoupling capacitor is connected to one end of the second inductor, the other end of the second inductor is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the radio frequency capacitor, the other end of the radio frequency capacitor is grounded, the other end of the first resistor is further connected to one end of the third inductor, and the other end of the third inductor is connected to the first end of the first inductor.

6. The power amplification unit further comprises a chip package module; 6. The circuit of claim 1, wherein the first end of the power transistor is grounded via the chip package module, the second end of the power transistor is connected to the signal input port via the chip package module, the third end of the power transistor is connected to the first end of the first inductor, the second end of the first inductor is connected to the chip package module, and the first inductor is connected to the signal output port via the chip package module.

7. 7. The circuit of claim 2, wherein the first inductor and / or the third inductor are disposed using wire bonding techniques.

8. The envelope impedance peak of the power amplifier circuit is at the parallel resonant frequency, and the parallel resonant frequency of the power amplifier circuit satisfies the following formula: [0010] However, L 2 is the inductance value of the second inductor, and L 3 is the inductance value of the third inductor, and C ds is the capacitance of the parasitic capacitor of the power transistor, and C f 8. The circuit of claim 1, wherein:

9. 9. The circuit of claim 1, wherein the power amplifier circuit further comprises a power supply, the power supply configured to supply power to the power transistor.

10. A radio frequency system comprising a power supply, a radio frequency antenna and a power amplifier circuit according to any one of claims 1 to 9, the power supply is configured to provide power to the power amplifier circuit; A radio frequency system, wherein the radio frequency antenna is configured to transmit a radio frequency signal amplified by the power amplifier circuit.

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