Broadband radio frequency power amplifier

Abstract

The utility model provides a broadband radio frequency power amplifier, which comprises a carrier power amplification unit, a peak power amplification unit, a 1 / 4 wavelength line, a bandwidth compensation unit and an output matching network, and is characterized in that the carrier power amplification unit is configured to receive a first input signal, and the output of the carrier power amplification unit is connected to an impedance combining point through the 1 / 4 wavelength line; a peak power amplification unit configured to receive a second input signal and provide a signal amplified by the peak power amplification unit to an impedance combining point; the bandwidth compensation unit is configured to be connected to the impedance combining point so as to provide bandwidth compensation for the broadband radio frequency power amplifier; and the output matching network is configured between the impedance combining point and the output end of the broadband radio frequency power amplifier so as to provide output impedance matching for the broadband radio frequency power amplifier.

Description

Technical Field

[0001] The utility model relates to the field of wireless communication, and more specifically, to a broadband radio frequency power amplifier for improving bandwidth. Background Art

[0002] A power amplifier is an important component in modern communication, which is a device that provides energy supplied by a power supply to an alternating current signal. The Doherty amplifier is a commonly used amplifier in wireless communication systems. Its efficiency optimization is achieved through the dynamic load modulation effect, which relies on the cooperation of two amplifiers operating in different states to change the amplifier load, thereby optimizing the back-off efficiency of the amplifier. More specifically, the carrier amplifier usually operates in the AB class mode, while the peak amplifier operates in the C class mode. At low power, only the carrier amplifier is turned on, and its load is at a higher position to maintain high efficiency. At high power, the peak amplifier is turned on, and the load of the carrier amplifier is modulated to a lower position to generate a high-power output. Compared with a common amplifier, this improves the power back-off efficiency of the amplifier in wireless communication applications.

[0003] In mobile phone 5G communication, the power consumption problem caused by power increase is becoming increasingly obvious. At the same time, for non-constant envelope modulation methods, their peak-to-average power ratio (PAPR) is relatively high, and the power amplifier mostly operates in the back-off mode. Therefore, for the power amplifier, the back-off efficiency is even more important.

[0004] In addition, since the massive multiple-input multiple-output (Massive MIMO) technology is introduced in 5G communication to improve the communication capacity and bandwidth, the bandwidth problem of the radio frequency power amplifier needs to be considered. In the wide frequency band range, not only high efficiency but also high back-off need to be ensured. Therefore, a broadband radio frequency power amplifier with high bandwidth is required. Summary of the Utility Model

[0005] One aspect of the utility model provides a broadband radio frequency power amplifier, comprising: a carrier power amplification unit, a peak power amplification unit, a 1 / 4 wavelength line, a bandwidth compensation unit, and an output matching network, characterized in that: the carrier power amplification unit is configured to receive a first input signal and connect its output to an impedance combining point through a 1 / 4 wavelength line; the peak power amplification unit is configured to receive a second input signal and provide the signal amplified by the peak power amplification unit to the impedance combining point; the bandwidth compensation unit is configured to be connected to the impedance combining point to provide bandwidth compensation for the broadband radio frequency power amplifier; and the output matching network is configured between the impedance combining point and the output end of the broadband radio frequency power amplifier to provide output impedance matching for the broadband radio frequency power amplifier, wherein the first input signal and the second input signal are of the same magnitude and have a phase difference of 90 degrees.

[0006] On one aspect of the present utility model, a broadband radio frequency power amplifier is provided, characterized in that the bandwidth compensation unit is configured as a 1 / 4 wavelength line, one end of the 1 / 4 wavelength line is connected to the impedance combining point, and the other end thereof is connected to the ground node.

[0007] On one aspect of the present utility model, a broadband radio frequency power amplifier is provided, characterized in that the bandwidth compensation unit is configured as a 1 / 2 wavelength line, one end of the 1 / 2 wavelength line is connected to the impedance combining point, and the other end thereof is connected to the open circuit node.

[0008] On one aspect of the present utility model, a broadband radio frequency power amplifier is provided, characterized in that the bandwidth compensation unit is configured to include a first inductor L1 and a first capacitor C1, and the first ends of the first inductor L1 and the first capacitor C1 are connected at the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path, and the second ends of the first inductor L1 and the first capacitor C1 are grounded.

[0009] On one aspect of the present utility model, a broadband radio frequency power amplifier is provided, characterized in that the bandwidth compensation unit is configured to include a first branch and a second branch. The first branch includes a first inductor L1, a second inductor L2, a first capacitor C1 and a second capacitor C2. The first inductor L1, the second inductor L2 and the second capacitor C2 are connected in series between the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path and the ground node, and the first capacitor C1 is connected between the intermediate node of the first inductor L1 and the second inductor L2 and the ground node; the second branch includes a third capacitor C3, and the third capacitor C3 is connected between the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path and the ground node.

[0010] On one aspect of the present utility model, a broadband radio frequency power amplifier is provided, characterized in that the carrier power amplification unit or the peak power amplification unit includes one of an HBT amplifier, a CMOS amplifier, a SiGe amplifier, a single-ended amplifier, a differential amplifier or a cascode structure power amplifier.

[0011] One aspect of the present utility model provides a broadband radio frequency power amplifier, characterized in that when the carrier power amplification unit and the peak power amplification unit are configured as differential amplifiers, a first differential carrier output terminal of the carrier power amplification unit is connected to a first differential peak output terminal of the peak power amplification unit through a first 1 / 4 wavelength line to form a first impedance combining point; a second differential carrier output terminal of the carrier power amplification unit is connected to a second differential peak output terminal of the peak power amplification unit through a second 1 / 4 wavelength line to form a second impedance combining point; and the bandwidth compensation unit is configured to be connected between the first impedance combining point and the second impedance combining point.

[0012] One aspect of the present utility model provides a broadband radio frequency power amplifier, characterized in that the bandwidth compensation unit includes a first inductor L1 and a first capacitor C1, and a first end of the first inductor L1 and the first capacitor C1 is connected to the first impedance combining point, and a second end of the first inductor L1 and the first capacitor C1 is connected to the second impedance combining point.

[0013] One aspect of the present utility model provides a broadband radio frequency power amplifier, characterized in that the bandwidth compensation unit includes a first inductor L1, and a first end of the first inductor L1 is connected to the first impedance combining point, and a second end of the first inductor L1 is connected to the second impedance combining point.

[0014] One aspect of the present utility model provides a broadband radio frequency power amplifier, characterized in that the carrier power amplification unit operates in Class A or Class AB state, and the peak power amplification unit operates in Class C state. Description of the Drawings

[0015] Figure 1 is a schematic diagram showing a conventional Doherty power amplifier;

[0016] Figure 2 is a schematic diagram showing the impedance bandwidth of a conventional Doherty power amplifier;

[0017] FIGS. 3(a) and 3(b) are schematic diagrams showing a broadband Doherty power amplifier with bandwidth compensation according to an embodiment of the present utility model;

[0018] FIGS. 4(a) and 4(b) are schematic diagrams showing the impedance bandwidth of a broadband Doherty power amplifier with bandwidth compensation according to an embodiment of the present utility model;

[0019] FIGS. 5(a) and 5(b) are schematic diagrams showing a broadband Doherty power amplifier with bandwidth compensation according to an embodiment of the present utility model; and

[0020] Figure 6 is a schematic diagram showing a broadband Doherty power amplifier with bandwidth compensation according to another embodiment of the present invention. Detailed implementation mode

[0021] Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document of the present invention. The terms "coupled", "connected" and their derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with each other. The terms "transmit", "receive" and "communicate" and their derivatives cover both direct and indirect communication. The terms "comprise" and "include" and their derivatives mean including but not limited to. The term "or" is inclusive, meaning and / or. The phrase "associated with" and its derivatives mean including, included within, interconnected, containing, contained within, connected or connected to, coupled or coupled to, communicating with, cooperating with, interwoven, juxtaposed, adjacent, bound or bound to, having, having an attribute, having a relationship or having a relationship with, etc. The term "controller" refers to any device, system or part thereof that controls at least one operation. Such a controller can be implemented in hardware, or in a combination of hardware and software and / or firmware. The functions associated with any particular controller can be centralized or distributed, whether local or remote. The phrase "at least one", when used with a list of items, means that different combinations of one or more of the listed items can be used, and it may only require one item in the list. For example, "at least one of A, B, C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C.

[0022] Definitions of other specific words and phrases are provided throughout this patent document of the present invention. Those of ordinary skill in the art should understand that in many cases, if not most cases, such definitions apply to the prior and future use of the words and phrases so defined.

[0023] In this patent document of the present invention, the application combination of circuit blocks and the division of sub-circuit blocks are only for illustration, and within the scope not departing from this disclosure, the application combination of circuit blocks and the division of sub-circuit blocks can have different ways.

[0024] The following discussion Figures 1 to 6 and the various embodiments for describing the principles of this disclosure in this patent document of the present invention are only for illustration and should not be construed in any way as limiting the scope of this disclosure. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged system or device.

[0025] At present, a conventional Doherty amplifier includes two amplifiers, a carrier amplifier and a peak amplifier. In a conventional Doherty amplifier, the carrier and peak amplifiers are of the same size, and the input signals are of the same size with a 90-degree phase difference. Among them, a 1 / 4 wavelength line or its LC equivalent circuit is placed after the carrier amplifier. When the peak amplifier is not turned on, the output impedance is converted to a high impedance by the 1 / 4 wavelength line or its LC equivalent circuit to improve the back-off efficiency.

[0026] Figure 1 FIG. shows a schematic diagram of a conventional Doherty power amplifier.

[0027] As Figure 1 shown, when the peak amplifier is not turned on, the load of the carrier amplifier has its output impedance R converted to a high impedance 4*R by the 1 / 4 wavelength line or its LC equivalent circuit to improve the back-off efficiency. When the peak amplifier is fully turned on, the loads of both the carrier amplifier and the peak amplifier are 2*R, and the saturation power reaches the maximum at this time. However, on the one hand, the load impedance conversion ratio of the carrier amplifier is 4, and on the other hand, both the phase shift bandwidth and the matching bandwidth of the 1 / 4 wavelength line are relatively narrow, unable to meet the application requirements of a broadband amplifier.

[0028] Figure 2 FIG. shows a schematic diagram of the impedance bandwidth of a conventional Doherty power amplifier.

[0029] Referring to Figure 2 , for an impedance of 50 ohms, a conventional Doherty power amplifier can only be achieved in a very narrow frequency band within 3 - 4 GHz. Therefore, it cannot meet the application requirements of a broadband amplifier.

[0030] According to an embodiment of the present invention, a broadband Doherty power amplifier is provided. By adding a bandwidth compensation unit for bandwidth compensation at the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path, the design of a broadband power amplifier is realized.

[0031] FIG. 3(a) and FIG. 3(b) show schematic diagrams of a broadband Doherty power amplifier with bandwidth compensation according to an embodiment of the present invention.

[0032] Referring to FIG. 3(a), the bandwidth compensation unit according to the present invention is configured as a 1 / 4 wavelength line, one end of which is connected to the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path, and the other end of which is grounded. Referring to FIG. 3(b), the bandwidth compensation unit according to the present invention can also be configured as a 1 / 2 wavelength line, one end of which is connected to the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path, and the other end of which is connected to an open circuit node.

[0033] FIG. 4(a) and FIG. 4(b) are schematic diagrams showing the impedance bandwidth of a broadband Doherty power amplifier with bandwidth compensation according to an embodiment of the present invention.

[0034] Referring to FIG. 4(a) and FIG. 4(b), the bandwidth of the radio frequency power amplifier is improved. Although the load impedance conversion ratio of the carrier amplifier remains 4, its impedance bandwidth increases significantly.

[0035] FIG. 5(a) and FIG. 5(b) are schematic diagrams showing a broadband Doherty power amplifier with bandwidth compensation according to another embodiment of the present invention.

[0036] Since the quarter-wavelength line or half-wavelength line added in the embodiment of the power amplifier shown in FIG. 3(a) and FIG. 3(b) occupies a relatively large area, FIG. 5(a) and FIG. 5(b) provide another implementation manner of the broadband Doherty power amplifier with bandwidth compensation according to the present invention.

[0037] Referring to FIG. 5(a), the bandwidth compensation unit according to the present invention is configured as a parallel-connected LC network, including a first inductor L1 and a first capacitor C1, and one end thereof is connected to the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path, and the other end thereof is grounded.

[0038] Referring to FIG. 5(b), the bandwidth compensation unit according to the present invention can also be configured to include two branches (a first branch and a second branch). Among them, the first branch includes a first inductor L1, a second inductor L2, a first capacitor C1 and a second capacitor C2. The first inductor L1, the second inductor L2, and the second capacitor C2 are connected in series between the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path and the ground node, and the first capacitor C1 is connected between the intermediate node of the first inductor L1 and the second inductor L2 and the ground node; the second branch includes a third capacitor C3, and the third capacitor C3 is connected between the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path and the ground node.

[0039] Referring to FIG. 5(a) and FIG. 5(b), by using an LC network to replace the quarter-wavelength line or half-wavelength line, the area of the circuit is effectively reduced, and the cost is saved.

[0040] Those skilled in the art should understand that the structure of the present invention can be applied to various power amplification unit circuits. For example, the power amplification unit can include an HBT amplifier, a CMOS amplifier, a SiGe amplifier, a single-ended amplifier, a differential amplifier, or an amplifier with a cascode structure.

[0041] Figure 6FIG. 0 is a schematic diagram of a broadband Doherty power amplifier with bandwidth compensation according to another embodiment of the present invention.

[0042] Referring Figure 6 , the carrier power amplification unit and the peak power amplification unit of the Doherty power amplifier are configured as differential amplifiers. The input signal is distributed to the carrier power amplification unit and the peak power amplification unit through the quadrature distribution unit, wherein the quadrature distribution unit is configured to provide two differential carrier unit input signals to the carrier power amplification unit; and provide two differential peak unit input signals to the peak power amplification unit, and the phase difference between the carrier unit input signal and the peak unit input signal is 90 degrees (i.e., the carrier unit input signal and the peak unit input signal are orthogonal signals). The first carrier differential output signal output by the carrier power amplification unit is connected to the output end of the first peak differential output signal output by the peak power amplification unit through a 1 / 4 wavelength line; and the second carrier differential output signal output by the carrier power amplification unit is connected to the output end of the second peak differential output signal output by the peak power amplification unit through a 1 / 4 wavelength line. In addition, a bandwidth compensation unit is connected between the output end of the first peak differential output signal and the output end of the second peak differential output signal. According to an embodiment of the present invention, the bandwidth compensation unit includes a first inductor L1 and a first capacitor C1 connected in parallel. According to another embodiment of the present invention, since the power amplifier further includes an output matching network, the bandwidth compensation unit only includes the first inductor L1 to further reduce the area occupied by the circuit and make the chip design more flexible.

[0043] Referring Figure 6 , according to an embodiment of the present invention, the carrier power amplification unit is configured as a two-stage power amplifier including a driver-stage carrier amplifier and a power-stage carrier amplifier, wherein the driver-stage carrier amplifier and the power-stage carrier amplifier are connected by a transformer winding to transmit differential carrier power amplification signals; the peak power amplification unit is configured as a two-stage power amplifier including a driver-stage peak amplifier and a power-stage peak amplifier, wherein the driver-stage peak amplifier and the power-stage peak amplifier are connected by a transformer winding to transmit differential peak power amplification signals.

[0044] Referring Figure 6 , according to an embodiment of the present invention, the RF power amplifier is configured to further include an output transformer, wherein the input winding of the output transformer is connected between the output end of the first peak differential output signal and the output end of the second peak differential output signal; one end of the output winding of the output transformer is grounded, and the other end is connected to the output end of the RF power amplifier to output the differential signal output by the output matching network as a single-ended RF output signal.

[0045] According to an embodiment of the present utility model, the carrier power amplification unit operates in Class A or Class AB state, and the peak power amplification unit operates in Class C state.

[0046] Although the present disclosure has been described with exemplary embodiments, various changes and modifications can be suggested to those skilled in the art. The present disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0047] Any description in the present utility model should not be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the subject matter of the utility model is defined only by the claims.

Claims

1. A broadband radio frequency power amplifier, comprising: A carrier power amplification unit, a peak power amplification unit, a 1 / 4 wavelength line, a bandwidth compensation unit, and an output matching network, characterized in that: The carrier power amplification unit is configured to receive a first input signal and connect its output to an impedance combining point through a 1 / 4 wavelength line; The peak power amplification unit is configured to receive a second input signal and provide the signal amplified by the peak power amplification unit to the impedance combining point; The bandwidth compensation unit is configured to be connected to the impedance combining point to provide bandwidth compensation for the broadband radio frequency power amplifier; and The output matching network is configured between the impedance combining point and the output end of the broadband radio frequency power amplifier to provide output impedance matching for the broadband radio frequency power amplifier, wherein the first input signal and the second input signal are of the same magnitude and have a phase difference of 90 degrees.

2. The broadband RF power amplifier according to claim 1, wherein The bandwidth compensation unit is configured as a 1 / 4 wavelength line, one end of which is connected to the impedance combining point and the other end of which is connected to a ground node.

3. The broadband RF power amplifier according to claim 1, wherein The bandwidth compensation unit is configured as a 1 / 2 wavelength line, one end of which is connected to the impedance combining point and the other end of which is connected to an open circuit node.

4. The broadband RF power amplifier according to claim 1, characterized in that, The bandwidth compensation unit is configured to include a first inductor L1 and a first capacitor C1, and the first ends of the first inductor L1 and the first capacitor C1 are connected at the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path, and the second ends of the first inductor L1 and the first capacitor C1 are grounded.

5. The broadband RF power amplifier according to claim 1, wherein The bandwidth compensation unit is configured to include a first branch and a second branch, The first branch includes a first inductor L1, a second inductor L2, a first capacitor C1, and a second capacitor C2. The first inductor L1, the second inductor L2, and the second capacitor C2 are connected in series between the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path and the ground node, and the first capacitor C1 is connected between the intermediate node of the first inductor L1 and the second inductor L2 and the ground node; The second branch includes a third capacitor C3, and the third capacitor C3 is connected between the impedance combining point of the carrier power amplification unit path and the peak power amplification unit path and the ground node.

6. The broadband RF power amplifier according to claim 1, characterized in that, The carrier power amplification unit or the peak power amplification unit includes one of an HBT amplifier, a CMOS amplifier, a SiGe amplifier, a single-ended amplifier, a differential amplifier, or a cascode structure power amplifier.

7. The broadband RF power amplifier according to claim 6, wherein, When the carrier power amplification unit and the peak power amplification unit are configured as differential amplifiers, The first differential carrier output end of the carrier power amplification unit is connected to the first differential peak output end of the peak power amplification unit through a first 1 / 4 wavelength line to form a first impedance combining point; The second differential carrier output end of the carrier power amplification unit is connected to the second differential peak output end of the peak power amplification unit through a second 1 / 4 wavelength line to form a second impedance combining point; and The bandwidth compensation unit is configured to be connected between the first impedance combining point and the second impedance combining point.

8. The broadband radio frequency power amplifier according to claim 7, wherein The bandwidth compensation unit includes a first inductor L1 and a first capacitor C1, and the first ends of the first inductor L1 and the first capacitor C1 are connected to the first impedance combining point, and the second ends of the first inductor L1 and the first capacitor C1 are connected to the second impedance combining point.

9. The broadband RF power amplifier according to claim 7, wherein The bandwidth compensation unit includes a first inductor L1, and the first end of the first inductor L1 is connected to the first impedance combining point, and the second end of the first inductor L1 is connected to the second impedance combining point.

10. The broadband RF power amplifier according to claim 1, wherein The carrier power amplification unit operates in Class A or Class AB state, and the peak power amplification unit operates in Class C state.

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