WO2023078061A1

WO2023078061A1 - Doherty radio frequency power amplifier

Info

Publication number: WO2023078061A1
Application number: PCT/CN2022/125437
Authority: WO
Inventors: 彭艳军; 宣凯; 郭嘉帅
Original assignee: 深圳飞骧科技股份有限公司
Priority date: 2021-11-05
Filing date: 2022-10-14
Publication date: 2023-05-11
Also published as: CN216390920U

Abstract

A Doherty radio frequency power amplifier, comprising a drive amplifier (1), a carrier input matching network (2), a carrier bias circuit (3), a carrier power amplifier (4), a peak input matching network (5), a peak bias circuit (6), a peak power amplifier (7), a first output matching network (8), a second output matching network (9), a power measurement circuit (10) and a peak bias control circuit (11). The drive amplifier (1) is used for amplifying an input radio frequency signal; the power measurement circuit (10) is used for measuring the radio frequency signal to generate a measurement result, determining an output power state of the Doherty radio frequency power amplifier according to the measurement result, and then generating a corresponding control signal according to the output power state; and the peak bias control circuit (11) is used for generating, according to the control signal, a peak bias control voltage corresponding to the control signal. The Doherty radio frequency power amplifier is small in layout area, good in linearity and high in power added efficiency.

Description

Doherty RF Power Amplifier

technical field

The utility model relates to the technical field of radio frequency integrated circuits, in particular to a Doherty radio frequency power amplifier.

Background technique

In order to meet people's requirements for high data communication rates, 5G wireless communication technology uses high-order quadrature amplitude modulation (QAM) technology, and the modulated signal has a very high peak-to-average ratio (PAPR). High peak-to-average ratio signals impose strict requirements on the linearity of RF power amplifiers. In order to ensure the undistorted transmission of the signal, the wireless communication system requires the RF power amplifier to work in a power back-off state far away from the power compression point, so as to ensure the linear amplification of the RF signal. However, the efficiency of RF power amplifiers is often designed to have the highest efficiency near the saturation region, and the efficiency at the power back-off point is significantly reduced. In order to improve the efficiency of RF power amplifiers during power back-off, the Doherty structure is a common method for designing RF power amplifiers.

The Doherty RF power amplifier of the related art generally includes a power divider, a main input matching network, a main power amplifier, a main output matching network, a main phase compensation network, a quarter-wavelength transmission line, a front auxiliary phase compensation network, an auxiliary input matching network, Auxiliary power amplifier, auxiliary output matching network, post-auxiliary phase compensation network and output matching network. Among them, the output matching network is connected to the external system load. Please refer to FIG. 1 , which is a schematic diagram of a circuit application of a Doherty radio frequency power amplifier in the related art. As an efficiency enhancement technology, the Doherty technology is mainly based on the active load pulling effect of the impedance transformation network at the output end of the power amplifier, so that the carrier power amplifier enters the saturation state in advance, thereby improving the power of the Doherty power amplifier in the fallback region. efficiency. Active Load Pull Technique (Active LoadPull Technique) is the key to realize the Doherty power amplifier. Another related art Doherty RF power amplifier includes a driver amplifier, a power divider, a main power amplifier, an auxiliary power amplifier, a power combiner and a quarter-wavelength transmission line. Please refer to FIG. 2 , which is a schematic diagram of another circuit structure of a Doherty radio frequency power amplifier in the related art. Among them, after the input signal is amplified by the driving amplifier, the input power is divided into two by the power divider, one is input to the input end of the main power amplifier, and the other is connected to the input end of the auxiliary power amplifier after passing through a quarter-wavelength transmission line. The output of the main power amplifier is connected to the first input of the power combiner through a quarter-wavelength transmission line, the output of the auxiliary power amplifier is directly connected to the second input of the power combiner, and the output of the power combiner is connected to the output load . The working principle of the Doherty RF power amplifier in the related art is: the main power amplifier is biased at Class AB or Class B, and the auxiliary power amplifier is biased at Class C. In the low output power state, the auxiliary power amplifier is turned off, and the load impedance of the main power amplifier is 2Ropt. In the state of high output power, the auxiliary power amplifier is turned on, the load impedance of the main power amplifier changes from 2Ropt to Ropt with the increase of input power, and the load impedance of the auxiliary power amplifier also gradually decreases from infinite value to Ropt with the increase of input power, The outputs of the two amplifiers are combined by a power combiner. Due to this change in load modulation, the Doherty RF power amplifier exhibits higher efficiency when the power is backed off.

However, the size of the power splitter and the quarter-wavelength transmission line of the Doherty RF power amplifier in the related art is too large to be implemented on a chip, especially in the Sub-6GHz frequency band. longer. The small-scale characteristics of monolithic microwave integrated circuits require that small-sized passive devices must be used when designing Doherty RF power amplifiers using integrated circuit technology. The related art Doherty RF power amplifier can only work in a narrow frequency band. At the same time, in order to ensure that the auxiliary power amplifier in the Doherty power amplifier is not turned on in a low input power state, it usually works in a class-C mode. Class C mode RF power amplifiers usually have lower power gain, and have very low efficiency when starting up, and the linearity of output power is also lower than that of Class AB power amplifiers, which will seriously affect the overall performance of Doherty power amplifiers.

Therefore, it is necessary to provide a novel broadband Doherty radio frequency power amplifier with compact size and achievable integrated circuit technology to solve the above problems.

Utility model content

Aiming at the deficiencies of the prior art above, the utility model proposes a Doherty radio frequency power amplifier with small layout area, good linearity and high power added efficiency.

In order to solve the above-mentioned technical problems, the embodiment of the utility model provides a kind of Doherty radio frequency power amplifier, described Doherty power amplifier comprises driving amplifier, carrier input matching network, carrier bias circuit, carrier power amplifier, peak input matching network, peak Bias circuit, peak power amplifier, first output matching network, second output matching network, power detection circuit and peak bias control circuit;

The drive amplifier is used to amplify the input radio frequency signal;

The carrier input matching network is connected to the drive amplifier for performing 90-degree phase shift and impedance matching on the output of the drive amplifier;

The carrier bias circuit is connected to the carrier power amplifier for providing carrier bias voltage to the carrier power amplifier;

The carrier power amplifier is connected to the carrier input matching network, and is used to amplify the power of the signal output by the carrier input matching network;

The power detection circuit is used to detect the radio frequency signal and generate a detection result, judge the output power state of the Doherty power amplifier according to the detection result, and then generate a corresponding control signal according to the output power state;

The peak bias control circuit is connected to the power detection circuit for generating a peak bias control voltage corresponding to the control signal according to the control signal;

The peak input matching network is connected to the drive amplifier for impedance matching the output of the drive amplifier;

The peak bias circuit is connected between the peak bias control circuit and the peak power amplifier, and is used to generate a peak bias voltage corresponding to the peak bias control voltage according to the peak bias control voltage , and will provide the peak bias voltage to the peak power amplifier;

The peak power amplifier is connected to the peak input matching network, and is used to amplify the power of the signal output by the peak input matching network;

The first output matching network is connected to the carrier power amplifier for performing 90-degree phase shift and impedance matching on the output signal of the carrier power amplifier;

The second output matching network is respectively connected to the peak power amplifier and the first output matching network, and is used for impedance matching the output signal of the peak power amplifier, and for the signal output by the peak power amplifier and The signals output by the first output matching network are synthesized into one output, which is also used to connect the system load. Preferably, the input end of the drive amplifier is used as the input end of the Doherty power amplifier;

The output end of the drive amplifier is respectively connected to the input end of the carrier input matching network, the input end of the peak input matching network and the input end of the power detection circuit;

The output terminal of the power detection circuit is connected to the input terminal of the peak bias control circuit, and the output terminal of the peak bias control circuit is connected to the input terminal of the peak bias circuit;

The output end of the carrier input matching network is respectively connected to the input end of the carrier power amplifier and the output end of the carrier bias circuit, and the input end of the carrier bias circuit is used to connect the carrier bias voltage;

The output terminal of the carrier power amplifier is connected to the input terminal of the first output matching network;

an output terminal of the first output matching network connected to a first input terminal of the second output matching network;

The output end of the peak input matching network is respectively connected to the input end of the peak power amplifier and the output end of the peak bias circuit;

The output terminal of the peak power amplifier is connected to the second input terminal of the second output matching network;

The output terminal of the second output matching network is used as the output terminal of the Doherty power amplifier.

Preferably, the carrier input matching network is a high-pass T-type network for 90-degree phase shift and impedance transformation; the first output matching network is a low-pass π-type network for 90-degree phase shift and impedance transformation.

Preferably, the carrier input matching network includes a second inductor, a second capacitor and a third capacitor; the first end of the second capacitor serves as the input end of the carrier input matching network, and the first end of the second capacitor One end is connected to the output end of the drive amplifier; the second end of the second capacitor is respectively connected to the first end of the third capacitor and the first end of the second inductance; The second end is connected to ground; the second end of the third capacitor is used as the output end of the carrier input matching network;

The first output matching network includes a fourth capacitor, a fifth capacitor, and a third inductor; the first end of the third inductor serves as an input end of the first output matching network, and the first end of the third inductor terminals are respectively connected to the output terminal of the carrier power amplifier and the first terminal of the fourth capacitor; the second terminal of the third inductance is used as the output terminal of the peak power amplifier, and the first terminal of the third inductance The two ends are connected to the first end of the fifth capacitor; the second end of the fourth capacitor and the second end of the fifth capacitor are both connected to ground.

Preferably, the second output matching network includes a high-pass T-type network for 90-degree phase shift and impedance transformation.

Preferably, the second output matching network includes a fourth inductor, a fifth inductor, a sixth inductor, a seventh inductor, a sixth capacitor, and a seventh capacitor;

The first end of the fourth inductance is used as the second input end of the second output matching network, and the first end of the fourth inductance is connected to the output end of the peak power amplifier;

The second terminal of the fourth inductor is used as the second input terminal of the second output matching network, and the second terminal of the fourth inductor is respectively connected to the second terminal of the fifth inductor and the second terminal of the sixth inductor. a first end of the inductance, the first end of the fifth inductance is connected to a power supply voltage;

The second end of the sixth inductor is respectively connected to the first end of the sixth capacitor and the first end of the seventh inductor, and the second end of the sixth capacitor is connected to ground;

The second terminal of the seventh inductor is connected to the first terminal of the seventh capacitor, and the second terminal of the seventh capacitor serves as the output terminal of the second output matching network.

Preferably, the peak input matching network includes a first capacitor; the first end of the first capacitor is used as the input end of the peak input matching network, and the first end of the first capacitor is connected to the drive amplifier the output terminal of the first capacitor; the second terminal of the first capacitor is used as the output terminal of the peak input matching network.

Preferably, the Doherty power amplifier further includes a first inductor, and the power input terminal of the driving amplifier is connected to the power supply voltage after being connected in series with the first inductor.

Preferably, the Doherty power amplifier also includes a power coupler, the power coupler is used to couple the input radio frequency signal, and output the coupled signal to the power detection circuit;

The input end of the power coupler is used as the input end of the Doherty power amplifier, the first output end of the power coupler is connected to the input end of the drive amplifier, and the second output end of the power coupler is connected to the input terminal of the power detection circuit;

The output end of the drive amplifier is respectively connected to the input end of the carrier input matching network and the input end of the peak input matching network;

Preferably, the carrier input matching network, the peak input matching network, the first output matching network and the second output matching network are all lumped parameter circuits.

Compared with the related art, the Doherty radio frequency power amplifier of the present utility model removes the larger power divider of the related art, the carrier input matching network is set in front of the input end of the carrier power amplifier, and the peak input is set in front of the input end of the peak power amplifier. matching network. This setting enables uniform or non-uniform power distribution of the input power through the impedance value of the carrier input matching network and the impedance value of the peak input matching network, which can replace a large-sized power divider. The output terminal of the carrier power amplifier is connected to the input terminal of the first output matching network, and both the carrier input matching network and the first output matching network are phase compensation networks with 90-degree phase shift and impedance matching. This structure enables the first output matching network to simultaneously function as a quarter-wavelength impedance transformation line to achieve a 90-degree phase shift. At the same time, the carrier input matching network includes a phase compensation network to ensure that the combined power of the carrier power amplifier and the peak power amplifier is the largest when the output power is high, so that the power added efficiency of the Doherty radio frequency power amplifier of the present invention is high. In addition, the above-mentioned circuit replaces the quarter-wavelength impedance transformation line of the related art, so that the layout area of the Doherty radio frequency power amplifier is small. The Doherty radio frequency power amplifier of the utility model detects the radio frequency signal through a power detection circuit to generate a detection result, and judges the output power state of the Doherty power amplifier according to the detection result, and then generates a corresponding control signal according to the output power state ; Generate a peak bias control voltage corresponding to the control signal according to the control signal through the peak bias control circuit, and control the opening or closing of the peak power amplifier through the peak bias control voltage, so that The peak power amplifier is also biased to class AB, and its power gain and linearity are the same as those of the carrier power amplifier. The output power after the combination of the two channels not only doubles the output power, but also ensures good linearity.

Description of drawings

Below in conjunction with accompanying drawing, describe the utility model in detail. Through the detailed description in conjunction with the following drawings, the content of the above or other aspects of the present utility model will become clearer and easier to understand. In the attached picture,

Fig. 1 is a kind of circuit application schematic diagram of the Doherty radio frequency power amplifier of related art;

Fig. 2 is another kind of circuit structure schematic diagram of the Doherty radio frequency power amplifier of related art;

Fig. 3 is a kind of circuit structure schematic diagram of the utility model Doherty radio frequency power amplifier;

FIG. 4 is a schematic diagram of another circuit structure of the Doherty radio frequency power amplifier of the present invention.

Detailed ways

The specific embodiment of the utility model will be described in detail below in conjunction with the accompanying drawings.

The specific implementations/embodiments described here are specific specific implementations of the present utility model, and are used to illustrate the concept of the present utility model. Limitations on the scope of utility models. In addition to the embodiments described here, those skilled in the art can also adopt other obvious technical solutions based on the claims of the application and the contents disclosed in the description, and these technical solutions include adopting any obvious changes made to the embodiments described here. The replacement and modified technical solutions are all within the protection scope of the present utility model.

(Embodiment 1)

The embodiment of the utility model provides a Doherty radio frequency power amplifier 100 .

Please also refer to FIG. 3 , wherein FIG. 3 is a schematic diagram of a circuit structure of an embodiment of the Doherty radio frequency power amplifier 100 of the present invention.

The Doherty power amplifier 100 described in the utility model includes a driver amplifier 1, a carrier input matching network 2, a carrier bias circuit 3, a carrier power amplifier 4, a peak input matching network 5, a peak bias circuit 6, a peak power amplifier 7, a first An output matching network 8 , a second output matching network 9 , a power detection circuit 10 and a peak bias control circuit 11 .

The drive amplifier 1 is used to amplify the input radio frequency signal.

The carrier input matching network 2 is connected to the driving amplifier 1 . The carrier input matching network 2 is used to perform 90-degree phase shift and impedance matching on the output end of the driving amplifier 1 .

The carrier bias circuit 3 is connected to the carrier power amplifier 4 . The carrier bias circuit 3 is used for providing carrier bias voltage to the carrier power amplifier 4 .

The carrier power amplifier 4 is connected to the carrier input matching network 3 . The carrier power amplifier 4 is used for power amplifying the signal output by the carrier input matching network 2.

The power detection circuit 10 is used to detect the radio frequency signal and generate a detection result, judge the output power state of the Doherty power amplifier 100 according to the detection result, and then generate a corresponding control signal according to the output power state.

The peak bias control circuit 11 is connected to the power detection circuit 10 . The peak bias control circuit 11 is used for generating a peak bias control voltage corresponding to the control signal according to the control signal.

The peak input matching network 5 is connected to the driving amplifier 1 . The peak input matching network 5 is used for impedance matching the output end of the driving amplifier 1 .

The peak bias circuit 6 is connected between the peak bias control circuit 11 and the peak power amplifier 7 . The peak bias circuit 6 is used to generate a peak bias voltage corresponding to the peak bias control voltage according to the peak bias control voltage, and provide the peak bias voltage to the peak power amplifier 7 .

The peak power amplifier 7 is connected to the peak input matching network 5 . The peak power amplifier 7 is used to amplify the power of the signal output by the peak input matching network 5 .

The first output matching network 8 is connected to the carrier power amplifier 7 . The first output matching network 8 is used to perform 90-degree phase shift and impedance matching on the output signal of the carrier power amplifier 4 .

The second output matching network 9 is connected to the peak power amplifier 7 and the first output matching network 8 respectively. The second output matching network 9 is used for performing impedance matching on the output signal of the peak power amplifier 7, and synthesizing the signal output by the peak power amplifier 7 and the signal output by the first output matching network 8 output, and is also used to connect system loads.

Wherein, the connection relationship of the utility model Doherty radio frequency power amplifier 100 is:

The input terminal of the driving amplifier 1 is used as the input terminal RFin of the Doherty power amplifier 100 .

The output terminal of the driving amplifier 1 is respectively connected to the input terminal of the carrier input matching network 2 , the input terminal of the peak input matching network 5 and the input terminal of the power detection circuit 10 .

The output terminal of the power detection circuit 10 is connected to the input terminal of the peak bias control circuit 11 , and the output terminal of the peak bias control circuit 11 is connected to the input terminal of the peak bias circuit 6 .

The output terminal of the carrier input matching network 2 is respectively connected to the input terminal of the carrier power amplifier 4 and the output terminal of the carrier bias circuit 3, and the input terminal of the carrier bias circuit 3 is used to connect the carrier bias circuit Voltage Vreg.

The output terminal of the carrier power amplifier 4 is connected to the input terminal of the first output matching network 8 .

The output terminal of the first output matching network 8 is connected to the first input terminal of the second output matching network 9 .

The output terminal of the peak input matching network 5 is respectively connected to the input terminal of the peak power amplifier 7 and the output terminal of the peak bias circuit 6 .

The output terminal of the peak power amplifier 7 is connected to the second input terminal of the second output matching network 9 .

The output terminal of the second output matching network 9 is used as the output terminal RFout of the Doherty power amplifier 100 for connecting to the system load R.

In the above structure, the carrier input matching network 2 is arranged in front of the input end of the carrier power amplifier 4 , and the peak input matching network 5 is arranged in front of the input end of the peak power amplifier 7 . This setting enables uniform or non-uniform power distribution of the input power through the impedance value of the carrier input matching network 2 and the impedance value of the peak input matching network 5, thereby replacing the larger power divider in the related art, Therefore, the layout area of the Doherty radio frequency power amplifier 100 is small, and it is easy to be integrated on a chip of GaAs HBT process.

Wherein, both the carrier input matching network 2 and the first output matching network 8 include a phase compensation network for 90-degree phase shift and impedance transformation. This structure enables the first output matching network to simultaneously function as a quarter-wavelength impedance transformation line to achieve a 90-degree phase shift. At the same time, the carrier input matching network includes a phase compensation network to ensure the maximum combined power of the carrier power amplifier 4 and the peak power amplifier 7 when the output power is high. Therefore, the power added efficiency of the Doherty radio frequency power amplifier 100 of the present invention is high. In addition, the above-mentioned circuit replaces the quarter-wavelength impedance transformation line of the related art, so that the layout area of the Doherty RF power amplifier 100 is small, and it is easy to be integrated on a chip of GaAs HBT process.

In this embodiment, the phase compensation network is any one of a high-pass T-type network, a high-pass π-type network, a low-pass T-type network, and a low-pass π-type network.

Wherein, the Qualcomm T-type network and the search Qualcomm π-type network realize a phase shift of +90 degrees. The low-pass T-network and the low-pass π-network implement a phase shift of -90 degrees.

In practical applications, the type of matching network is selected according to the input and output impedance characteristics of the carrier power amplifier 4 and the peak power amplifier 7 . The carrier input matching network 2 is a Qualcomm T-type network or a Qualcomm π-type network. The first output matching network 8 is a low-pass T-type network or a low-pass π-type network. In the first embodiment, the carrier input matching network 2 is a high-pass T-type network for 90-degree phase shift and impedance transformation, so as to suppress low-frequency clutter signal interference. The first output matching network 8 is a low-pass π-type network used for 90-degree phase shift and impedance transformation to suppress high-order harmonics.

In the first embodiment, the carrier input matching network 2 , the peak input matching network 5 , the first output matching network 8 and the second output matching network 9 are all lumped parameter circuits. The lumped parameter circuit is divided by the size of the circuit electrical device and the wavelength of the working signal. The actual circuit can be divided into a distributed parameter circuit and a lumped parameter circuit. A circuit that satisfies the d<<λ condition is called a lumped parameter circuit. Its characteristic is that the voltage between any two terminals in the circuit and the current flowing into any device port are completely determined, regardless of the geometric size and spatial position of the device. A circuit that does not satisfy the d<<λ condition is called a distributed parameter circuit. Its characteristic is that the voltage and current in the circuit are a function of time and are related to the geometric size and spatial position of the device. The use of lumped parameter circuits facilitates implementation using MMIC technology. Thereby the utility model Doherty radio frequency power amplifier 100 is easy to be integrated on the chip of a GaAs HBT process.

The concrete circuit structure of the utility model Doherty radio frequency power amplifier 100 is:

The Doherty power amplifier 100 further includes a first inductor L1, and the power input terminal of the driving amplifier 1 is connected to the power supply voltage Vcc after being connected in series with the first inductor L1.

The carrier input matching network 2 includes a second inductor L2, a second capacitor C2 and a third capacitor C3. The first terminal of the second capacitor C2 is used as the input terminal of the carrier input matching network 2, and the first terminal of the second capacitor C2 is connected to the output terminal of the driving amplifier 1. The second terminal of the second capacitor C2 is respectively connected to the first terminal of the third capacitor C3 and the first terminal of the second inductor L2. The second end of the second inductor L2 is connected to the ground GND. The second terminal of the third capacitor C3 is used as the output terminal of the carrier input matching network 2 . Wherein, the carrier input matching network 2 implements a -90 degree phase shift.

The peak input matching network 5 includes a first capacitor C1. The first terminal of the first capacitor C1 is used as the input terminal of the peak input matching network 5 , and the first terminal of the first capacitor C1 is connected to the output terminal of the driving amplifier 1 . The second terminal of the first capacitor C1 is used as the output terminal of the peak input matching network 5 .

The first output matching network 8 includes a fourth capacitor C4, a fifth capacitor C5 and a third inductor L3. The first end of the third inductance L3 is used as the input end of the first output matching network 8, and the first end of the third inductance L3 is respectively connected to the output end of the carrier power amplifier 4 and the first end of the first output matching network. The first end of four capacitors C4. The second terminal of the third inductor L3 is used as the output terminal of the peak power amplifier 7, and the second terminal of the third inductor L3 is connected to the first terminal of the fifth capacitor C5. Both the second terminal of the fourth capacitor C4 and the second terminal of the fifth capacitor C5 are connected to the ground GND. Wherein, the first output matching network 8 implements a phase shift of +90 degrees.

The second output matching network 9 includes a fourth inductor L4, a fifth inductor 5, a sixth inductor L6, a seventh inductor L7, a sixth capacitor C6 and a seventh capacitor C7.

The first terminal of the fourth inductor L4 is used as the second input terminal of the second output matching network 9 , and the first terminal of the fourth inductor L4 is connected to the output terminal of the peak power amplifier 7 .

The second end of the fourth inductance L4 is used as the second input end of the second output matching network 9, and the second end of the fourth inductance L4 is respectively connected to the second end of the fifth inductance 5 and The first terminal of the sixth inductor L6 and the first terminal of the fifth inductor 5 are connected to the power supply voltage Vcc.

The second end of the sixth inductor L6 is respectively connected to the first end of the sixth capacitor C6 and the first end of the seventh inductor L7, and the second end of the sixth capacitor C6 is connected to the ground GND.

The second terminal of the seventh inductor L7 is connected to the first terminal of the seventh capacitor C7 , and the second terminal of the seventh capacitor C7 is used as the output terminal of the second output matching network 9 .

Wherein, the second output matching network 9 includes a high-pass T-type network 91 for 90-degree phase shift and impedance transformation. The high-pass T-type network 91 is composed of the sixth inductor L6, the seventh inductor L7 and the sixth capacitor C6. The Qualcomm T-network 91 achieves a phase shift of +90 degrees.

The circuit operating principle of the utility model Doherty radio frequency power amplifier 100 is:

Both the carrier power amplifier 4 and the peak power amplifier 7 are biased in class AB. The opening of the peak power amplifier 7 is controlled by the peak bias control circuit 11:

When the Doherty RF power amplifier 100 is in the high output power mode, the output power of the driving amplifier 1 is relatively high, and the power detection circuit 10 connected to the output of the driving amplifier 1 detects a high output power state, and the peak bias control circuit 11 outputs a high power level, control the peak bias circuit 6 of the peak power amplifier 7 to output a current or voltage signal, turn on the peak power amplifier 7, and then complete power synthesis with the carrier power amplifier 4.

When the Doherty power amplifier 100 was in the output low power mode, the output power of the driving amplifier 1 was low, and the power detection circuit 10 connected to the output of the driving amplifier 1 detected the low output power state, and the peak bias control circuit 11 output a low power level, the peak bias circuit 6 that controls the peak power amplifier 7 does not output current or voltage signals, the peak power amplifier 7 is turned off, and only the carrier power amplifier 4 works, and the maximum output power is P0/4 (the maximum output power after the synthesis of the two power amplifiers) Power is P0).

Since the peak power amplifier 7 is also biased to class AB, the power gain and linearity of the peak power amplifier 7 are the same as those of the carrier power amplifier 4, and the output power after the two-way synthesis not only doubles the output power of the Doherty power amplifier 100, but also ensures The Doherty power amplifier 100 has good linearity.

(Example 2)

Embodiment 2 provides a Doherty radio frequency power amplifier 200 . Please refer to FIG. 4 , which is a schematic circuit structure diagram of another embodiment of the Doherty radio frequency power amplifier provided by the embodiment of the present invention.

The Doherty radio frequency power amplifier 200 is basically the same as the Doherty radio frequency power amplifier 100, two differences are: the Doherty power amplifier 100 also includes a power coupler 12, the power coupler 12 is used to couple the input radio frequency signal, and Output the coupled signal to the power detection circuit 10 .

The specific circuit connection relationship of the Doherty RF power amplifier 200 is:

The input end of the power coupler 12 is used as the input end of the Doherty power amplifier 100, the first output end of the power coupler 12 is connected to the input end of the drive amplifier 1, and the first output end of the power coupler 12 is connected to the input end of the drive amplifier 1. The two output terminals are connected to the input terminals of the power detection circuit 10 .

The output terminal of the driving amplifier 1 is respectively connected to the input terminal of the carrier input matching network 2 and the input terminal of the peak input matching network 5 .

The output end of the carrier input matching network 2 is respectively connected to the input end of the carrier power amplifier 4 and the output end of the carrier bias circuit 3, and the input end of the carrier bias circuit 3 is used to connect the carrier bias circuit set the voltage.

The output terminal of the second output matching network 9 is used as the output terminal of the Doherty power amplifier 100 .

Wherein, the different working principles of the Doherty RF power amplifier 200 and the Doherty RF power amplifier 100 are: the power coupler 12 detects the power of the corresponding transmission power in the radio frequency signal by driving the power coupler before the amplifier. level to determine whether the Doherty power amplifier 100 is in a low output power mode or a high power mode, and then determine whether to turn on the peak power amplifier 7 .

In addition, the Doherty RF power amplifier 200 has fewer circuit components and high circuit performance, and is easy to be integrated on a GaAs HBT process chip.

It should be pointed out that the relevant circuits, resistors, capacitors, inductors and power amplifiers used in this utility model are all commonly used circuits and components in the field, and the corresponding specific indicators and parameters are adjusted according to actual applications. Here, no detailed description will be given. repeat.

Compared with the related art, the Doherty radio frequency power amplifier of the present utility model removes the larger power divider of the related art, the carrier input matching network is set in front of the input end of the carrier power amplifier, and the peak input is set in front of the input end of the peak power amplifier. matching network. This setting enables uniform or non-uniform power distribution of the input power through the impedance value of the carrier input matching network and the impedance value of the peak input matching network, thereby replacing a power divider with a large size. The output terminal of the carrier power amplifier is connected to the input terminal of the first output matching network, and both the carrier input matching network and the first output matching network are phase compensation networks with 90-degree phase shift and impedance matching. This structure enables the first output matching network to simultaneously function as a quarter-wavelength impedance transformation line to achieve a 90-degree phase shift. At the same time, the carrier input matching network includes a phase compensation network to ensure that the combined power of the carrier power amplifier and the peak power amplifier is the largest when the output power is high, so that the power added efficiency of the Doherty radio frequency power amplifier of the present invention is high. In addition, the above-mentioned circuit replaces the quarter-wavelength impedance transformation line of the related art, so that the layout area of the Doherty radio frequency power amplifier is small. The Doherty radio frequency power amplifier of the utility model detects the radio frequency signal through a power detection circuit to generate a detection result, and judges the output power state of the Doherty power amplifier according to the detection result, and then generates a corresponding control signal according to the output power state ; Generate a peak bias control voltage corresponding to the control signal according to the control signal through the peak bias control circuit, and control the opening or closing of the peak power amplifier through the peak bias control voltage, so that The peak power amplifier is also biased to class AB, and its power gain and linearity are the same as those of the carrier power amplifier. The output power after the combination of the two channels not only doubles the output power, but also ensures good linearity.

It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the utility model rather than limit the scope of the utility model, those of ordinary skill in the art should understand that without departing from the spirit and scope of the utility model Any modifications or equivalent replacements made to the present utility model under the premise of the present utility model shall be covered within the scope of the present utility model. Further, words appearing in the singular include the plural and vice versa unless the context otherwise requires. Additionally, all or a portion of any embodiment may be utilized with all or a portion of any other embodiment, unless stated otherwise.

Claims

A kind of Doherty radio frequency power amplifier, it is characterized in that, described Doherty power amplifier comprises driver amplifier, carrier input matching network, carrier bias circuit, carrier power amplifier, peak input matching network, peak bias circuit, peak power amplifier, first an output matching network, a second output matching network, a power detection circuit, and a peak bias control circuit;

The drive amplifier is used to amplify the input radio frequency signal;

The carrier input matching network is connected to the drive amplifier for performing 90-degree phase shift and impedance matching on the output of the drive amplifier;

The carrier bias circuit is connected to the carrier power amplifier for providing carrier bias voltage to the carrier power amplifier;

The carrier power amplifier is connected to the carrier input matching network, and is used to amplify the power of the signal output by the carrier input matching network;

The power detection circuit is used to detect the radio frequency signal and generate a detection result, judge the output power state of the Doherty power amplifier according to the detection result, and then generate a corresponding control signal according to the output power state;

The peak bias control circuit is connected to the power detection circuit for generating a peak bias control voltage corresponding to the control signal according to the control signal;

The peak input matching network is connected to the drive amplifier for impedance matching the output of the drive amplifier;

The peak bias circuit is connected between the peak bias control circuit and the peak power amplifier, and is used to generate a peak bias voltage corresponding to the peak bias control voltage according to the peak bias control voltage , and will provide the peak bias voltage to the peak power amplifier;

The peak power amplifier is connected to the peak input matching network, and is used to amplify the power of the signal output by the peak input matching network;

The first output matching network is connected to the carrier power amplifier for performing 90-degree phase shift and impedance matching on the output signal of the carrier power amplifier;

The second output matching network is respectively connected to the peak power amplifier and the first output matching network, and is used for impedance matching the output signal of the peak power amplifier, and for the signal output by the peak power amplifier and The signals output by the first output matching network are synthesized into one output, which is also used to connect the system load.
Doherty power amplifier according to claim 1, is characterized in that,

The input end of described driving amplifier is used as the input end of described Doherty power amplifier;

The output end of the drive amplifier is respectively connected to the input end of the carrier input matching network, the input end of the peak input matching network and the input end of the power detection circuit;

The output terminal of the power detection circuit is connected to the input terminal of the peak bias control circuit, and the output terminal of the peak bias control circuit is connected to the input terminal of the peak bias circuit;

The output end of the carrier input matching network is respectively connected to the input end of the carrier power amplifier and the output end of the carrier bias circuit, and the input end of the carrier bias circuit is used to connect the carrier bias voltage;

The output terminal of the carrier power amplifier is connected to the input terminal of the first output matching network;

an output terminal of the first output matching network connected to a first input terminal of the second output matching network;

The output end of the peak input matching network is respectively connected to the input end of the peak power amplifier and the output end of the peak bias circuit;

The output terminal of the peak power amplifier is connected to the second input terminal of the second output matching network;

The output terminal of the second output matching network is used as the output terminal of the Doherty power amplifier.
The Doherty power amplifier according to claim 2, wherein the carrier input matching network is a high-pass T-type network used for 90-degree phase shift and impedance transformation; the first output matching network is used for 90-degree phase shift Low-pass π-type network for shifting and impedance transformation.
Doherty power amplifier according to claim 3, is characterized in that,

The carrier input matching network includes a second inductor, a second capacitor, and a third capacitor; the first end of the second capacitor is used as the input end of the carrier input matching network, and the first end of the second capacitor is connected to To the output end of the drive amplifier; the second end of the second capacitor is respectively connected to the first end of the third capacitor and the first end of the second inductance; the second end of the second inductance connected to ground; the second end of the third capacitor is used as the output end of the carrier input matching network;

The first output matching network includes a fourth capacitor, a fifth capacitor, and a third inductor; the first end of the third inductor serves as an input end of the first output matching network, and the first end of the third inductor terminals are respectively connected to the output terminal of the carrier power amplifier and the first terminal of the fourth capacitor; the second terminal of the third inductance is used as the output terminal of the peak power amplifier, and the first terminal of the third inductance The two ends are connected to the first end of the fifth capacitor; the second end of the fourth capacitor and the second end of the fifth capacitor are both connected to ground.
The Doherty power amplifier according to claim 4, wherein the second output matching network comprises a high-pass T-type network for 90 degree phase shift and impedance transformation.
The Doherty power amplifier according to claim 5, wherein the second output matching network comprises a fourth inductor, a fifth inductor, a sixth inductor, a seventh inductor, a sixth capacitor and a seventh capacitor;

The first end of the fourth inductance is used as the second input end of the second output matching network, and the first end of the fourth inductance is connected to the output end of the peak power amplifier;

The second terminal of the fourth inductor is used as the second input terminal of the second output matching network, and the second terminal of the fourth inductor is respectively connected to the second terminal of the fifth inductor and the second terminal of the sixth inductor. a first end of the inductance, the first end of the fifth inductance is connected to a power supply voltage;

The second end of the sixth inductor is respectively connected to the first end of the sixth capacitor and the first end of the seventh inductor, and the second end of the sixth capacitor is connected to ground;

The second terminal of the seventh inductor is connected to the first terminal of the seventh capacitor, and the second terminal of the seventh capacitor serves as the output terminal of the second output matching network.
The Doherty power amplifier according to claim 4, wherein the peak input matching network includes a first capacitor; the first end of the first capacitor is used as an input of the peak input matching network, and the first The first end of a capacitor is connected to the output end of the driving amplifier; the second end of the first capacitor is used as the output end of the peak input matching network.
The Doherty power amplifier according to claim 4, characterized in that the Doherty power amplifier further comprises a first inductor, and the power supply input end of the driving amplifier is connected to a power supply voltage after being connected in series with the first inductor.
The Doherty power amplifier according to claim 1, characterized in that, the Doherty power amplifier also includes a power coupler, the power coupler is used to couple the input radio frequency signal, and output the coupled signal to the power detection circuit;

The input end of the power coupler is used as the input end of the Doherty power amplifier, the first output end of the power coupler is connected to the input end of the drive amplifier, and the second output end of the power coupler is connected to the input terminal of the power detection circuit;

The output terminal of the power detection circuit is connected to the input terminal of the peak bias control circuit, and the output terminal of the peak bias control circuit is connected to the input terminal of the peak bias circuit;

The output end of the drive amplifier is respectively connected to the input end of the carrier input matching network and the input end of the peak input matching network;

The output end of the carrier input matching network is respectively connected to the input end of the carrier power amplifier and the output end of the carrier bias circuit, and the input end of the carrier bias circuit is used to connect the carrier bias voltage;

The output terminal of the carrier power amplifier is connected to the input terminal of the first output matching network;

an output terminal of the first output matching network connected to a first input terminal of the second output matching network;

The output end of the peak input matching network is respectively connected to the input end of the peak power amplifier and the output end of the peak bias circuit;

The output terminal of the peak power amplifier is connected to the second input terminal of the second output matching network;

The output terminal of the second output matching network is used as the output terminal of the Doherty power amplifier.
The Doherty power amplifier according to claim 1, wherein the carrier input matching network, the peak input matching network, the first output matching network and the second output matching network are all lumped parameter circuits .