Transformer-based Doherty power amplifier

Abstract

The present invention provides a transformer-based Doherty power amplifier, comprising: a driver stage amplifier, which is coordinated to provide an amplified input signal to an input orthogonalizer; an input orthogonalizer, which is configured to receive the amplified input signal and generate four orthogonal signals; a power stage amplifier, which is configured to output a first carrier output signal and a first peak output signal, as well as a second carrier output signal and a second peak output signal; an output transformer, which is configured to receive and output the first carrier output signal and the first peak output signal, as well as the second carrier output signal and the second peak output signal, and output a power-synthesized output signal, wherein the power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency integrated circuits, and in particular to a transformer-based Doherty radio frequency power amplifier circuit for use in a mobile terminal. Background Art

[0002] The power amplifier is an important component in modern communications. It is a device configured to provide the energy provided by the power supply to the AC signal. The Doherty amplifier is an amplifier commonly used in wireless communication systems. The Doherty amplifier optimizes efficiency through the dynamic load modulation effect. By cooperating with two amplifiers working in different states, the amplifier load changes, thereby optimizing the amplifier's back-off efficiency. More specifically, the carrier amplification path usually operates in Class AB mode, while the bias peak amplifier operates in Class C mode. At low power, only the main amplifier is turned on, and its load is at a higher position to maintain high efficiency; at high power, the auxiliary amplifier is turned on and the main amplifier load is modulated to a lower position to produce high power output. Compared with ordinary amplifiers, this improves the power back-off efficiency of the amplifier in wireless communication applications.

[0003] In 5G mobile communications, power consumption issues caused by increased power consumption are becoming increasingly prominent. Furthermore, for non-constant envelope modulation schemes, the peak-to-average ratio (PAPR) of the RF signal is high, for example, reaching 7dB to 9dB. Power amplifiers (PAs) spend most of their time operating in back-off mode. Therefore, back-off efficiency becomes even more important for PAs, as reduced efficiency reduces the efficiency of the entire wireless communication system, leading to rapid battery drain in mobile devices and shortened standby time.

[0004] Currently, common Doherty amplifiers include two amplifiers, a carrier amplifier and a peak amplifier. In a symmetrical Doherty amplifier, the carrier and peak amplifiers are of the same size, the input signals are of the same size, and the phases differ by 90 degrees. 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 1 / 4 wavelength line or its LC equivalent circuit converts the output impedance to high impedance to improve the back-off efficiency. For existing Doherty amplifiers, on the one hand, for lower frequency broadband amplifiers, the 1 / 4 wavelength line occupies too large an area, and its LC equivalent circuit will reduce the matching bandwidth. On the other hand, even for high-frequency narrowband amplifiers, the 1 / 4 wavelength line occupies a smaller area, but due to the large high-frequency loss, it also affects the saturation efficiency of the carrier amplifier, that is, the back-off efficiency of the Doherty amplifier.

[0005] For a conventional Doherty amplifier, it is necessary to increase its operating bandwidth and reduce the output matching loss of the carrier amplifier. Summary of the Invention

[0006] This design provides a transformer-based differential Doherty power amplifier.

[0007] One aspect of the present invention provides a transformer-based Doherty power amplifier, comprising: a driver stage amplifier, which is coordinated to receive an input signal and provide the amplified input signal to an input orthogonalizer; an input orthogonalizer, which is configured to receive the amplified input signal and generate four orthogonal signals; a power stage amplifier, which is configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer, which is configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power-synthesized output signal, wherein the power stage amplifier is configured so that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open.

[0008] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal and the second power stage amplifier outputs a second peak output signal.

[0009] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the input orthogonal device includes a first transformer, a first power divider, a second power divider, a first phase shifter, and a second phase shifter, wherein the first transformer is configured to receive an input signal after being amplified by a driver stage amplifier and generate two signals with the same amplitude and a phase difference of 180 degrees, wherein the first power divider is configured to receive the first signal output by the first transformer and generate a first carrier input signal and a first peak input signal, the first carrier input signal is provided to the first input end of the first power stage amplifier, and the first peak input signal is provided to the second input end of the first power stage amplifier after being phase-shifted by the first phase shifter, wherein the second power divider is configured to receive the second signal output by the first transformer and generate a second carrier input signal and a second peak input signal, the second carrier input signal is provided to the first input end of the second power stage amplifier, and the second peak input signal is provided to the second input end of the second power stage amplifier after being phase-shifted by the second phase shifter.

[0010] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the input quadrature includes a first transformer and a first hybrid coupler and a second hybrid coupler. The first transformer is configured to receive an input signal amplified by a driver stage amplifier and generate two signals having the same amplitude and a phase difference of 180 degrees. The first hybrid coupler receives the first signal output by the first transformer to generate a first carrier input signal provided to a first input terminal of the first power stage amplifier and a first peak input signal provided to a second input terminal of the first power stage amplifier. The second input terminal of the first hybrid coupler is connected to a ground node via a first resistor. The second hybrid coupler receives the second signal output by the first transformer to generate a second carrier input signal provided to the first input terminal of the second power stage amplifier and a second peak input signal provided to the second input terminal of the second power stage amplifier. The second input terminal of the second hybrid coupler is connected to the ground node via a second resistor.

[0011] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the output transformer includes a third phase shifter, a fourth phase shifter, a second transformer, a third transformer and a fourth transformer, wherein the first carrier output terminal of the first power stage amplifier is connected to the first input terminal of the second transformer, and the first peak output terminal of the first power stage amplifier is connected to the second input terminal of the second transformer through the third phase shifter, wherein the second carrier output terminal of the second power stage amplifier is connected to the first input terminal of the third transformer, and the second peak output terminal of the second power stage amplifier is connected to the second input terminal of the third transformer through the fourth phase shifter, and wherein two signals with a phase difference of 180° between the second transformer and the third transformer are input to the fourth transformer to output the power-synthesized output signal through the fourth transformer.

[0012] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the output transformer includes a third phase shifter, a fourth phase shifter, a first inductor, a second inductor, and a third inductor, wherein the first inductor, the second inductor, and the third inductor are configured to be distributed in parallel, and the first inductor and the third inductor are arranged in anti-phase to form a first output transformer, a second output transformer, and a third output transformer respectively between the first inductor, the second inductor, and the third inductor, wherein the first carrier output terminal of the first power stage amplifier and the second carrier output terminal of the second power stage amplifier are connected to both ends of the first inductor, and wherein the first peak output terminal of the first power stage amplifier is connected to one end of the third inductor through the third phase shifter, and the second peak output terminal of the second power stage amplifier is connected to the other end of the third inductor through the fourth phase shifter, wherein the second inductor is arranged between the first inductor and the third inductor, one end of which is connected to the ground node, and the other end is connected to the output terminal of the Doherty power amplifier.

[0013] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the output transformer includes a third phase shifter, a fourth phase shifter, a fourth transformer and a fifth transformer, wherein the first carrier output terminal of the first power stage amplifier is connected to the first input terminal of the fourth transformer, and the first peak output terminal of the first power stage amplifier is connected to the second input terminal of the fourth transformer through the third phase shifter, wherein the second carrier output terminal of the second power stage amplifier is connected to the first input terminal of the fifth transformer, and the second peak output terminal of the second power stage amplifier is connected to the second input terminal of the fifth transformer through the fourth phase shifter, the first output terminal of the fourth transformer is connected to the first output terminal of the fifth transformer, and the second output terminal of the fourth transformer and the second output terminal of the fifth transformer are respectively connected to the ground node, wherein the first output terminal of the fourth transformer and the first output terminal of the fifth transformer are in phase.

[0014] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the output transformer includes a third hybrid coupler, a fourth hybrid coupler, and a sixth transformer. The first carrier output of the first power stage amplifier is connected to the first input of the third hybrid coupler, and the first peak output of the first power stage amplifier is connected to the second input of the third hybrid coupler. The second carrier output of the second power stage amplifier is connected to the first input of the fourth hybrid coupler, and the second peak output of the second power stage amplifier is connected to the second input of the fourth hybrid coupler. The first output of the third hybrid coupler is connected to the first input of the sixth transformer, and the first output of the fourth hybrid coupler is connected to the second input of the sixth transformer. The second output of the third hybrid coupler is connected to a ground node via a third resistor, and the second output of the fourth hybrid coupler is connected to the ground node via a fourth resistor. The first output of the third hybrid coupler and the first output of the fourth hybrid coupler output two signals with a phase difference of 180°.

[0015] An aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed by a capacitor and an inductor, or a π-type LC network formed by a capacitor and an inductor.

[0016] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or common-source common-gate structure amplifier formed by CMOS, HBT, or SiGe processes.

[0017] One aspect of the present invention provides a transformer-based Doherty power amplifier, wherein the transformer-based Doherty power amplifier is configured for use in an N77 or N79 frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram showing a transformer-based differential Doherty power amplifier structure according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram showing a circuit state of a Doherty power amplifier according to an embodiment of the present invention when only a carrier amplifier is working;

[0020] Figure 3 is a schematic diagram showing an implementation of a Doherty power amplifier according to an embodiment of the present invention; and

[0021] Figure 4 is a circuit diagram showing a transformer-based differential Doherty power amplifier structure according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Before proceeding with the detailed description below, it may be helpful to set forth the definitions of certain words and phrases used throughout this patent document. The terms "couple," "connect," and their derivatives refer to any direct or indirect communication or connection between two or more elements, regardless of whether those elements are in physical contact with each other. The terms "transmit," "receive," and "communicate," and their derivatives, encompass both direct and indirect communication. The terms "include," "comprise," 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 with, coupled or coupled with, communicate with, cooperate with, intertwine, juxtapose, approach, bound or bound with, have, have an attribute of, have a relationship with, or have a relationship with, etc. The term "controller" refers to any device, system, or portion thereof that controls at least one operation. Such a controller may be implemented using hardware, or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether local or remote. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one of the items in the list may be needed. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0023] Definitions for other specific words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior and future uses of such defined words and phrases.

[0024] In this patent document, the application combination of modules and the division level of sub-modules are only used for illustration. Without departing from the scope of this disclosure, the application combination of modules and the division level of sub-modules can have different forms.

[0025] Figure 1 FIG. 1 is a schematic diagram showing a structure of a transformer-based differential Doherty power amplifier according to an embodiment of the present invention.

[0026] refer to Figure 1 According to an embodiment of the present invention, a transformer-based differential Doherty power amplifier includes a driver stage amplifier, an input orthogonalizer, a power stage amplifier, and an output transformer. The RF input is connected to the Doherty power amplifier via the driver stage amplifier of the first stage driver amplifier.

[0027] After the input signal is amplified by the driver-stage amplifier, it is input to the input quadrature. According to an embodiment of the present invention, the input quadrature includes a transformer TR1, a first power divider, a second power divider, and first and second phase shifters. The input quadrature is configured to generate four mutually orthogonal signals.

[0028] First, the input signal amplified by the driver stage amplifier is divided into two signals with the same amplitude and a phase difference of 180 degrees through the first transformer TR1.

[0029] The first signal output by the first transformer TR1 is provided to the first power divider, the first carrier signal in the signal divided by the first power divider is provided to the first input terminal of the first power stage amplifier, and the first peak signal in the signal divided by the first power divider is phase-shifted by the first phase shifter (for example, after a 90° phase shift) and then provided to the second input terminal of the first power stage amplifier.

[0030] The second signal output by the first transformer TR1 is provided to the second power divider, the second carrier signal in the signal divided by the second power divider is provided to the first input terminal of the second power stage amplifier, and the second peak signal in the signal divided by the second power divider is phase-shifted by the second phase shifter (for example, after a 90° phase shift) and then provided to the second input terminal of the second power stage amplifier.

[0031] The output of the first power stage amplifier is connected to the second transformer TR2, which performs power synthesis and converts the quadrature signal into a single-ended signal. The first carrier output of the first power stage amplifier is connected to the first input of the second transformer TR2, and the first peak output of the first power stage amplifier is phase shifted (e.g., 90°) by a third phase shifter before being connected to the second input of the second transformer TR2.

[0032] The output of the second power stage amplifier is connected to the third transformer TR3, which performs power synthesis and converts the quadrature signal into a single-ended signal. The second carrier output of the second power stage amplifier is connected to the first input of the third transformer TR3, and the second peak output of the second power stage amplifier is phase-shifted (e.g., 90°) by a fourth phase shifter before being connected to the second input of the third transformer TR3.

[0033] The two signals with a phase difference of 180° from the second transformer TR2 and the third transformer TR3 are input to the fourth transformer TR4, so that the two differential Doherty signals with a phase difference of 180° are power-combined by the fourth transformer TR4 and output as an output signal.

[0034] According to an embodiment of the present invention, the phase shifter may include a CLC network formed by a capacitor and an inductor, or a π-type LC network formed by a capacitor and an inductor. In addition, according to an embodiment of the present invention, while the phase shifter performs phase compensation (e.g., 90° phase compensation) on the signal, impedance matching or transformation can be achieved.

[0035] Figure 2 FIG. 1 is a schematic diagram showing a circuit state of a Doherty power amplifier according to an embodiment of the present invention when only a carrier amplifier is working.

[0036] refer to Figure 2 During low-signal conditions (for example, when the input signal is less than the first threshold), the peak amplification paths in the first and second power-stage amplifiers are inoperative, and their output impedance is open. After passing through the 90° phase shifters (the third and fourth phase shifters), the peak amplification paths are transferred to an impedance short-circuit point and provided to one end of the second transformer TR2 or the third transformer TR3. Due to the impedance transfer characteristics of the transformer, the second transformer TR2 or the third transformer TR3 converts the impedance to a high-impedance state. For the carrier amplification paths in the first and second power-stage amplifiers, the impedance transfer process is completed by the transformer. Compared to a quarter-wavelength line or its LC equivalent circuit, the transformer has a significant bandwidth advantage. At the same time, the upper and lower carrier amplification paths are differential circuits, and the fourth transformer TR4 performs power synthesis.

[0037] When a large signal is present (e.g., when the input signal is greater than a second threshold), the peak amplification paths in the first power stage amplifier and the second power stage amplifier begin operating, and load modulate their respective carrier amplification paths through the second transformer TR2 or the third transformer TR3, so that the impedances at both ends of the transformers are the same and the phases are opposite. At this point, the first power stage amplifier and the second power stage amplifier are in differential operating mode, achieving the maximum output power state of the Doherty amplifier. According to an embodiment of the present invention, regardless of whether the transformer-based power amplifier is in a power-backoff state or a maximum output power state, the circuit always operates in differential mode. The output portion of the circuit utilizes a multi-transformer synthesis method, which can be flexibly implemented according to actual applications. For example, TR2 and TR3 can be integrated on a chip, TR4 can be implemented through a substrate to reduce losses, or TR2, TR3, and TR4 can be combined into a multi-input, single-output circuit structure.

[0038] Figure 3 is a schematic diagram illustrating an implementation of a Doherty power amplifier according to an embodiment of the present invention.

[0039] According to an embodiment of the present invention, the input orthogonalizer can be Figure 1 The first transformer TR1 is composed of a first power divider, a second power divider, a first phase shifter and a second phase shifter, wherein the first power divider and the second power divider can be configured as Wilkinson power dividers, and the first phase shifter and the second phase shifter can be configured as 90° phase shifters. In addition, according to an embodiment of the present invention, the input orthogonal device can also be composed of Figure 3 The first transformer TR1 and two hybrid couplers are used to reduce the chip area.

[0040] refer to Figure 3 The input orthogonal device includes a first transformer TR1 and two hybrid couplers, wherein the input signal after being amplified by the driver stage amplifier is divided into two signals with the same amplitude and a phase difference of 180 degrees through the first transformer TR1.

[0041] The first signal output by the first transformer TR1 is provided to the first input terminal of the first hybrid coupler. The first hybrid coupler generates a first carrier signal, which is provided to the first input terminal of the first power stage amplifier, and a first peak signal, which is provided to the second input terminal of the first power stage amplifier. The first carrier signal and the first peak signal are orthogonal to each other. Furthermore, the second input terminal of the first hybrid coupler is connected to the ground node via the first resistor R1.

[0042] The second signal output by the first transformer TR1 is provided to the first input terminal of the second hybrid coupler. The second hybrid coupler generates a second carrier signal, which is provided to the first input terminal of the second power stage amplifier, and a second peak signal, which is provided to the second input terminal of the second power stage amplifier. The second carrier signal and the second peak signal are orthogonal to each other. Furthermore, the second input terminal of the second hybrid coupler is connected to the ground node via a second resistor R2.

[0043] A transformer-based hybrid coupler (for example, configuring a transformer as a phase-shifting transformer to achieve a 90° phase shift) can replace the combination of a power divider and a phase shifter, achieving phase shifting while performing power distribution, thereby reducing chip area.

[0044] According to an embodiment of the present invention, the output transformer can be Figure 1 The output transformer may also be composed of a second transformer TR2, a third transformer TR3 and a fourth transformer TR4. Figure 3 There are two ways to form.

[0045] refer to Figure 3 An example of an output transformer according to an embodiment of the present invention may include a first inductor L1, a second inductor L2, and a third inductor L3. The first inductor L1, the second inductor L2, and the third inductor L3 are configured to be distributed in parallel, and the first inductor L1 and the third inductor L3 are arranged in anti-phase to form a first output transformer TR_out1, a second output transformer TR_out2, and a third output transformer TR_out3 between the first inductor L1, the second inductor L2, and the third inductor L3, respectively.

[0046] The first carrier output of the first power stage amplifier and the second carrier output of the second power stage amplifier are connected to both ends of the first inductor L1, and the first peak output of the first power stage amplifier passing through the third phase shifter and the second peak output of the second power stage amplifier passing through the fourth phase shifter are connected to both ends of the third inductor L3. The second inductor L2 is arranged between the first inductor L1 and the third inductor L3, with one end of the second inductor L2 connected to the ground node and the other end connected to the output terminal of the power amplifier to achieve power synthesis.

[0047] refer to Figure 3Another example of an output transformer according to an embodiment of the present invention may include a fourth transformer TR4 and a fifth transformer TR5. The first carrier output terminal of the first power stage amplifier is connected to the first input terminal of the fourth transformer TR4, and the first peak output terminal of the first power stage amplifier is connected to the second input terminal of the fourth transformer TR4 after being phase-shifted (for example, after being phase-shifted by 90°) by a third phase shifter. The second carrier output terminal of the second power stage amplifier is connected to the first input terminal of the fifth transformer TR5, and the second peak output terminal of the second power stage amplifier is connected to the second input terminal of the fifth transformer TR5 after being phase-shifted (for example, after being phase-shifted by 90°) by a fourth phase shifter. The first output terminal of the fourth transformer TR4 is connected to the first output terminal of the fifth transformer TR5, and the second output terminal of the fourth transformer TR4 and the second output terminal of the fifth transformer TR5 are respectively connected to the ground node.

[0048] According to an embodiment of the present invention, by adjusting the reference phase point of one of the fourth transformer TR4 or the fifth transformer TR5, the phase of the power output after passing through the fourth transformer TR4 or the fifth transformer TR5 is made the same, and finally a parallel synthesis method is used to reduce the number of transformers and chip area.

[0049] Figure 4 is a circuit diagram showing a transformer-based differential Doherty power amplifier structure according to one embodiment of the present invention.

[0050] refer to Figure 4 According to an embodiment of the present invention, a differential Doherty power amplifier includes a driver stage amplifier, an input orthogonal device, a first power stage amplifier, a second power stage amplifier, and an output transformer.

[0051] After the input signal is amplified by the driver-stage amplifier, it is input to the input quadrature. According to an embodiment of the present invention, the input quadrature includes a first transformer TR1 and two hybrid couplers. The input signal, after being amplified by the driver-stage amplifier, is split into two signals with equal amplitude and a phase difference of 180 degrees by the first transformer TR1.

[0052] The first signal output by the first transformer TR1 is provided to the first input terminal of the first hybrid coupler TR2. The first hybrid coupler TR2 generates a first carrier signal, which is provided to the first input terminal of the first power stage amplifier, and a first peak signal, which is provided to the second input terminal of the first power stage amplifier. Furthermore, the second input terminal of the first hybrid coupler TR2 is connected to the ground node via the first resistor R1.

[0053] The second signal output by the first transformer TR1 is provided to a first input terminal of a second hybrid coupler TR3. The second hybrid coupler TR3 generates a second carrier signal, which is provided to a first input terminal of the second power stage amplifier, and generates a second peak signal, which is provided to a second input terminal of the second power stage amplifier. Furthermore, a second input terminal of the second hybrid coupler TR3 is connected to a ground node via a second resistor R2.

[0054] A transformer-based hybrid coupler can replace the combination of a power divider and a phase shifter, achieving phase shift while performing power distribution, thereby reducing chip area.

[0055] The output of the first power stage amplifier is connected to the third hybrid coupler TR4, which performs power combination and converts the quadrature signal into a single-ended signal. The first carrier output of the first power stage amplifier is connected to the first input of the third hybrid coupler TR4, and the first peak output of the first power stage amplifier is connected to the second input of the third hybrid coupler TR4.

[0056] The output of the second power stage amplifier is connected to the fourth hybrid coupler TR5, which performs power combining and converts the quadrature signal into a single-ended signal. The second carrier output of the second power stage amplifier is connected to the first input of the fourth hybrid coupler TR5, and the second peak output of the second power stage amplifier is connected to the second input of the fourth hybrid coupler TR5.

[0057] A first output terminal of the third hybrid coupler TR4 is connected to a first input terminal of a sixth transformer TR6, and a first output terminal of the fourth hybrid coupler TR5 is connected to a second input terminal of the sixth transformer TR6, thereby achieving power combination via the sixth transformer TR6. Furthermore, a second output terminal of the third hybrid coupler TR4 is connected to a ground node via a third resistor R3, and a second output terminal of the fourth hybrid coupler TR5 is connected to a ground node via a fourth resistor R4.

[0058] By using a transformer-based hybrid coupler in the output transformer, the number of phase shifters can be reduced, enabling simultaneous phase shifting while combining power, thereby reducing chip area. Therefore, by employing a voltage regulator + hybrid coupler structure in both the input orthogonal device and the output transformer, the design can be further simplified, and the number of transformers and chip area can be reduced.

[0059] Without departing from the scope of the present invention, the technical solution according to the embodiment of the present invention can be applied to Doherty power amplifiers implemented in single-ended, differential or cascode structures of various CMOS, HBT and SiGe processes.

[0060] The Doherty power amplifier according to an embodiment of the present invention can meet the scenarios of 5G applications and can be configured for the N77 or N79 frequency bands. However, those skilled in the art should understand that the Doherty power amplifier according to an embodiment of the present invention can also be applied to other communication frequency bands without departing from the scope of the present invention.

[0061] Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.

[0062] Any description in the present invention should not be construed as implying that any particular element, step, or function is essential to be included in the scope of the claims. The scope of the patented subject matter is defined solely by the claims.

Claims

1. A transformer-based Doherty power amplifier, comprising: a driver stage amplifier adapted to receive an input signal and provide an amplified input signal to an input quadrature; an input quadrature device configured to receive the amplified input signal and generate four orthogonal signals; A power stage amplifier, configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power combined output signal, The power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open. The input orthogonal device includes a first transformer, a first power divider, a second power divider, a first phase shifter and a second phase shifter. The first transformer is configured to receive an input signal amplified by a driver amplifier and generate two signals with the same amplitude and a phase difference of 180 degrees. The first power divider is configured to receive the first signal output by the first transformer and generate a first carrier input signal and a first peak input signal. The first carrier input signal is provided to the first input terminal of the first power stage amplifier, and the first peak input signal is provided to the second input terminal of the first power stage amplifier after being phase-shifted by the first phase shifter. The second power divider is configured to receive a second signal output by the first transformer and generate a second carrier input signal and a second peak input signal. The second carrier input signal is provided to the first input end of the second power stage amplifier, and the second peak input signal is provided to the second input end of the second power stage amplifier after being phase-shifted by the second phase shifter.

2. The transformer-based Doherty power amplifier according to claim 1, wherein: The power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal, and the second power stage amplifier outputs a second peak output signal.

3. The transformer-based Doherty power amplifier according to claim 1 , wherein: The first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed of a capacitor and an inductor, or a π-type LC network formed of a capacitor and an inductor.

4. The transformer-based Doherty power amplifier according to claim 1 , wherein: The driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or cascode structure amplifier formed by CMOS, HBT, or SiGe processes.

5. The transformer-based Doherty power amplifier of claim 1 , wherein: The transformer-based Doherty power amplifier is configured for use in the N77 or N79 frequency band.

6. A transformer-based Doherty power amplifier comprising: a driver stage amplifier adapted to receive an input signal and provide an amplified input signal to an input quadrature; an input quadrature device configured to receive the amplified input signal and generate four orthogonal signals; A power stage amplifier, configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power combined output signal, The power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open. The input orthogonal device includes a first transformer, a first hybrid coupler and a second hybrid coupler. The first transformer is configured to receive an input signal amplified by a driver amplifier and generate two signals with the same amplitude and a phase difference of 180 degrees. The first hybrid coupler receives a first signal output by the first transformer to generate a first carrier input signal provided to a first input terminal of the first power stage amplifier and a first peak input signal provided to a second input terminal of the first power stage amplifier. The second input terminal of the first hybrid coupler is connected to a ground node via a first resistor. The second hybrid coupler receives the second signal output by the first transformer to generate a second carrier input signal provided to the first input terminal of the second power stage amplifier and a second peak input signal provided to the second input terminal of the second power stage amplifier. The second input terminal of the second hybrid coupler is connected to the ground node through a second resistor.

7. The transformer-based Doherty power amplifier according to claim 6, wherein: The power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal, and the second power stage amplifier outputs a second peak output signal.

8. The transformer-based Doherty power amplifier according to claim 6, wherein: The first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed of a capacitor and an inductor, or a π-type LC network formed of a capacitor and an inductor.

9. The transformer-based Doherty power amplifier of claim 6, wherein: The driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or cascode structure amplifier formed by CMOS, HBT, or SiGe processes.

10. The transformer-based Doherty power amplifier of claim 6, wherein: The transformer-based Doherty power amplifier is configured for use in the N77 or N79 frequency band.

11. A transformer-based Doherty power amplifier, comprising: a driver stage amplifier adapted to receive an input signal and provide an amplified input signal to an input quadrature; an input quadrature device configured to receive the amplified input signal and generate four orthogonal signals; A power stage amplifier, configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power combined output signal, The power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open. The output transformer includes a third phase shifter, a fourth phase shifter, a second transformer, a third transformer and a fourth transformer. The first carrier output terminal of the first power stage amplifier is connected to the first input terminal of the second transformer, and the first peak output terminal of the first power stage amplifier is connected to the second input terminal of the second transformer through the third phase shifter. The second carrier output terminal of the second power stage amplifier is connected to the first input terminal of the third transformer, and the second peak output terminal of the second power stage amplifier is connected to the second input terminal of the third transformer through the fourth phase shifter, and The two signals of the second transformer and the third transformer with a phase difference of 180° are input to the fourth transformer, so as to output the output signal after power synthesis through the fourth transformer.

12. The transformer-based Doherty power amplifier of claim 11, wherein: The power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal, and the second power stage amplifier outputs a second peak output signal.

13. The transformer-based Doherty power amplifier of claim 11, wherein: The first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed of a capacitor and an inductor, or a π-type LC network formed of a capacitor and an inductor.

14. The transformer-based Doherty power amplifier of claim 11, wherein: The driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or cascode structure amplifier formed by CMOS, HBT, or SiGe processes.

15. The transformer-based Doherty power amplifier of claim 11, wherein: The transformer-based Doherty power amplifier is configured for use in the N77 or N79 frequency band.

16. A transformer-based Doherty power amplifier comprising: a driver stage amplifier adapted to receive an input signal and provide an amplified input signal to an input quadrature; an input quadrature device configured to receive the amplified input signal and generate four orthogonal signals; A power stage amplifier, configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power combined output signal, The power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open. The output transformer includes a third phase shifter, a fourth phase shifter, a first inductor, a second inductor and a third inductor. The first inductor, the second inductor, and the third inductor are configured to be distributed in parallel, and the first inductor and the third inductor are arranged in anti-phase to form a first output transformer, a second output transformer, and a third output transformer respectively between the first inductor, the second inductor, and the third inductor. The first carrier output terminal of the first power stage amplifier and the second carrier output terminal of the second power stage amplifier are connected to both ends of the first inductor, and the first peak output terminal of the first power stage amplifier is connected to one end of the third inductor through a third phase shifter, and the second peak output terminal of the second power stage amplifier is connected to the other end of the third inductor through a fourth phase shifter. The second inductor is arranged between the first inductor and the third inductor, one end of the second inductor is connected to the ground node, and the other end of the second inductor is connected to the output end of the Doherty power amplifier.

17. The transformer-based Doherty power amplifier of claim 16, wherein: The power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal, and the second power stage amplifier outputs a second peak output signal.

18. The transformer-based Doherty power amplifier of claim 16, wherein: The first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed of a capacitor and an inductor, or a π-type LC network formed of a capacitor and an inductor.

19. The transformer-based Doherty power amplifier of claim 16, wherein: The driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or cascode structure amplifier formed by CMOS, HBT, or SiGe processes.

20. The transformer-based Doherty power amplifier of claim 16, wherein: The transformer-based Doherty power amplifier is configured for use in the N77 or N79 frequency band.

21. A transformer-based Doherty power amplifier comprising: a driver stage amplifier adapted to receive an input signal and provide an amplified input signal to an input quadrature; an input quadrature device configured to receive the amplified input signal and generate four orthogonal signals; A power stage amplifier, configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power combined output signal, The power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open. The output transformer includes a third phase shifter, a fourth phase shifter, a fourth transformer and a fifth transformer. The first carrier output terminal of the first power stage amplifier is connected to the first input terminal of the fourth transformer, and the first peak output terminal of the first power stage amplifier is connected to the second input terminal of the fourth transformer through the third phase shifter. The second carrier output terminal of the second power stage amplifier is connected to the first input terminal of the fifth transformer, and the second peak output terminal of the second power stage amplifier is connected to the second input terminal of the fifth transformer through a fourth phase shifter. The first output terminal of the fourth transformer is connected to the first output terminal of the fifth transformer, and the second output terminal of the fourth transformer and the second output terminal of the fifth transformer are respectively connected to the ground node. The first output end of the fourth transformer and the first output end of the fifth transformer are in phase.

22. The transformer-based Doherty power amplifier of claim 21, wherein: The power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal, and the second power stage amplifier outputs a second peak output signal.

23. The transformer-based Doherty power amplifier of claim 21 , wherein: The first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed of a capacitor and an inductor, or a π-type LC network formed of a capacitor and an inductor.

24. The transformer-based Doherty power amplifier of claim 21, wherein: The driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or cascode structure amplifier formed by CMOS, HBT, or SiGe processes.

25. The transformer-based Doherty power amplifier of claim 21 , wherein: The transformer-based Doherty power amplifier is configured for use in the N77 or N79 frequency band.

26. A transformer-based Doherty power amplifier comprising: a driver stage amplifier adapted to receive an input signal and provide an amplified input signal to an input quadrature; an input quadrature device configured to receive the amplified input signal and generate four orthogonal signals; A power stage amplifier, configured to include a first power stage amplifier and a second power stage amplifier, wherein the first power stage amplifier is configured to receive two orthogonal signals and is configured to output a first carrier output signal and a first peak output signal, wherein the second power stage amplifier is configured to receive another two orthogonal signals and is configured to output a second carrier output signal and a second peak output signal; an output transformer configured to receive and output the first carrier output signal and the first peak output signal and the second carrier output signal and the second peak output signal, and output a power combined output signal, The power stage amplifier is configured such that when the input signal is less than a first threshold, the output impedance of the first peak output terminal of the first power stage amplifier is open, and the output impedance of the second peak output terminal of the second power stage amplifier is open. The output transformer includes a third hybrid coupler, a fourth hybrid coupler and a sixth transformer. The first carrier output terminal of the first power stage amplifier is connected to the first input terminal of the third hybrid coupler, and the first peak output terminal of the first power stage amplifier is connected to the second input terminal of the third hybrid coupler. wherein the second carrier output terminal of the second power stage amplifier is connected to the first input terminal of the fourth hybrid coupler, and the second peak output terminal of the second power stage amplifier is connected to the second input terminal of the fourth hybrid coupler, and The first output end of the third hybrid coupler is connected to the first input end of the sixth transformer, and the first output end of the fourth hybrid coupler is connected to the second input end of the sixth transformer. The second output end of the third hybrid coupler is connected to the ground node via a third resistor, and the second output end of the fourth hybrid coupler is connected to the ground node via a fourth resistor. The first output end of the third hybrid coupler and the first output end of the fourth hybrid coupler output two signals with a phase difference of 180°.

27. The transformer-based Doherty power amplifier of claim 26, wherein: The power stage amplifier is configured such that when an input signal is greater than a second threshold, the first power stage amplifier outputs a first peak output signal, and the second power stage amplifier outputs a second peak output signal.

28. The transformer-based Doherty power amplifier of claim 26, wherein: The first phase shifter, the second phase shifter, the third phase shifter, or the fourth phase shifter includes a CLC network formed of a capacitor and an inductor, or a π-type LC network formed of a capacitor and an inductor.

29. The transformer-based Doherty power amplifier of claim 26, wherein: The driver stage amplifier and the power stage amplifier include at least one of a single-ended, differential, or cascode structure amplifier formed by CMOS, HBT, or SiGe processes.

30. The transformer-based Doherty power amplifier of claim 26, wherein: The transformer-based Doherty power amplifier is configured for use in the N77 or N79 frequency band.

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