CN220775788U - Active bias circuit for improving linearity of power amplifier and corresponding power amplifier - Google Patents
Active bias circuit for improving linearity of power amplifier and corresponding power amplifier Download PDFInfo
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- CN220775788U CN220775788U CN202322505226.4U CN202322505226U CN220775788U CN 220775788 U CN220775788 U CN 220775788U CN 202322505226 U CN202322505226 U CN 202322505226U CN 220775788 U CN220775788 U CN 220775788U
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Abstract
The utility model belongs to the technical field of power amplifier circuits, and particularly discloses an active bias circuit for improving linearity of a power amplifier and a corresponding power amplifier, wherein the bias circuit comprises a reference branch circuit and a linearization circuit; the linearization circuit comprises a first bipolar transistor, a first capacitor, a first resistor and a diode-connected second bipolar transistor; the collector of the first bipolar transistor is connected with the power supply voltage, the emitter is connected with one end of the first resistor, and the base is used as the input end of the linearization circuit on the one hand and grounded through the first capacitor on the other hand; the other end of the first resistor is used as an output end of the linearization circuit; the emitter of the second bipolar transistor is grounded, and the base is connected with the emitter of the first bipolar transistor. The utility model improves the linearity of the power amplifier by adding an extra diode-connected transistor, and simultaneously, the utility model also enables the power amplifier to obtain better power additional efficiency. The utility model is applicable to power amplifiers.
Description
Technical Field
The utility model belongs to the technical field of power amplifier circuits, and relates to an active bias circuit for improving linearity of a power amplifier and a corresponding power amplifier.
Background
The wireless communication technology is widely applied in the fields of satellite navigation, automobile radar, national defense safety and the like, and is permeated into aspects of daily life. In a wireless communication system, a power amplifier is located at the end of a transmitter and is responsible for amplifying a baseband signal, and the amplified signal is transmitted through an antenna.
The power amplifier is an important component of a wireless transceiver system, is a module with the greatest power consumption in the transceiver of the whole wireless communication system, and the quality of the performance directly influences the quality and the distance of signal transmission. In order to meet the demand for large data traffic within a limited spectrum of resources, a high order modulation scheme is an ideal choice. In order to amplify these modulated signals with high fidelity, higher demands are placed on the linearity of the applied power amplifier.
Disclosure of Invention
The utility model aims to provide an active bias circuit for improving the linearity of a power amplifier, which enables the power amplifier to realize better linearity and higher efficiency by adding an additional diode-connected transistor;
it is a further object of the present utility model to provide a power amplifier including the active bias circuit described above that improves the linearity of the power amplifier.
The technical scheme adopted by the utility model for realizing the purposes is as follows:
the active bias circuit for improving the linearity of the power amplifier comprises a reference branch and a linearization circuit, wherein the output end of the reference branch is connected with the input end of the linearization circuit, and the output end of the linearization circuit is used as the output end of the active bias circuit for improving the linearity of the power amplifier;
the linearization circuit comprises a first bipolar transistor, a first capacitor and a first resistor; the base electrode of the first bipolar transistor is grounded through a first capacitor on the one hand and is used as an input end of the linearization circuit on the other hand, the collector electrode of the first bipolar transistor is connected with a power supply voltage, the emitter electrode of the first bipolar transistor is connected with one end of a first resistor, and the other end of the first resistor is used as an output end of the linearization circuit;
the linearization circuit further includes a diode-connected second bipolar transistor; the base electrode and the collector electrode of the second bipolar transistor are connected with the emitter electrode of the first bipolar transistor and the common end of the first resistor after being short-circuited, and the emitter electrode of the second bipolar transistor is grounded.
As a limitation: the reference branch comprises a second resistor, a third diode-connected bipolar transistor and a fourth diode-connected bipolar transistor;
the collectors of the third bipolar transistor and the fourth bipolar transistor are respectively connected with the bases of the third bipolar transistor and the fourth bipolar transistor;
the common end of the collector electrode and the base electrode of the third bipolar transistor is connected with the power supply voltage through a second resistor on one hand and is used as the output end of the reference branch circuit on the other hand;
the emitter of the third bipolar transistor is connected with the common end of the collector and the base of the fourth bipolar transistor, and the emitter of the fourth bipolar transistor is grounded.
The utility model also provides a power amplifier, which comprises a power amplifying circuit and the active bias circuit for improving the linearity of the power amplifier, wherein the output end of the active bias circuit for improving the linearity of the power amplifier is connected with the bias signal input end of the power amplifying circuit.
As a limitation: the power amplifying circuit comprises a choke inductor, a power amplifying tube, a second capacitor and a third capacitor;
one end of the second capacitor is used as a radio frequency signal input end of the power amplifier, and the other end of the second capacitor is used as an amplifying circuit bias signal input end on one hand and is connected with a base electrode of the power amplifier tube on the other hand;
the emitter of the power amplifier tube is grounded, the collector of the power amplifier tube is connected with the power supply voltage through a choke inductor on one hand, and is connected with one end of a third capacitor on the other hand, and the other end of the third capacitor is used as a radio frequency signal output end of the power amplifier.
Compared with the prior art, the technical proposal adopted by the utility model has the following technical progress:
(1) The utility model realizes the improvement of linearity of the power amplifier by adding an additional diode-connected transistor, and simultaneously, better power additional efficiency is obtained;
(2) The utility model can make the power amplifier have smaller amplitude distortion and phase distortion;
(3) The power amplifier provided by the utility model has the advantages of good linearity, small amplitude distortion, small phase distortion and higher power addition efficiency.
The utility model belongs to the technical field of power amplifier circuits, and can enable a power amplifier to achieve better linearity and higher efficiency.
Drawings
The accompanying drawings are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate the utility model and together with the embodiments of the utility model, serve to explain the utility model.
In the drawings:
FIG. 1 is a schematic circuit diagram of embodiment 1 of the present utility model;
FIG. 2 is a schematic circuit diagram of embodiment 2 of the present utility model;
FIG. 3 is a graph showing the normalized output signal amplitude versus input signal at 3.5GHz for example 2 of the present utility model;
FIG. 4 is a graph showing the normalized output signal phase versus input signal at 3.5GHz in accordance with example 2 of the present utility model;
FIG. 5 is a graph showing the output 1dB compression point power versus frequency for example 2 of the present utility model;
fig. 6 is a graph comparing PAE with frequency variation when ldB compressed point power is output in example 2 of the present utility model.
Detailed Description
Preferred embodiments of the present utility model will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are presented for purposes of illustration and explanation only and are not intended to limit the present utility model.
Embodiment 1 an active bias Circuit for improving linearity of a Power Amplifier
The active bias circuit for improving the linearity of the power amplifier provided by the embodiment is an adaptive active bias circuit for improving the linearity of the power amplifier. The embodiment comprises a reference branch and a linearization circuit, wherein the output end of the reference branch is connected with the input end of the linearization circuit, and the output end of the linearization circuit is used as the output end of the active bias circuit for improving the linearity of the power amplifier.
As shown in fig. 1, the linearization circuit includes a first bipolar transistor Q1, a diode-connected second bipolar transistor Q2, a first capacitor C1, and a first resistor R1; the base electrode of the first bipolar transistor Q1 is grounded through a first capacitor C1 on the one hand and the input end of the linearization circuit on the other hand, the collector electrode of the first bipolar transistor Q1 is connected with a supply voltage VDD, the emitter electrode of the first bipolar transistor Q1 is connected with one end of a first resistor R1, and the other end of the first resistor R1 is used as the output end of the linearization circuit; the base electrode and the collector electrode of the second bipolar transistor Q2 are connected with the common end of the emitter electrode of the first bipolar transistor Q1 and the first resistor R1 after being short-circuited, and the emitter electrode of the second bipolar transistor Q2 is grounded.
As shown in fig. 1, the reference branch includes a second resistor R2, a diode-connected third bipolar transistor Q3, and a diode-connected fourth bipolar transistor Q4. The collectors of the third bipolar transistor Q3 and the fourth bipolar transistor Q4 are respectively connected with the bases of the third bipolar transistor Q3 and the fourth bipolar transistor Q4; the common end of the collector and the base of the third bipolar transistor Q3 is connected with the power supply voltage VDD through a second resistor R2 on one hand and is used as the output end of the reference branch on the other hand; the emitter of the third bipolar transistor Q3 is connected with the common terminal of the collector and the base of the fourth bipolar transistor Q4, and the emitter of the fourth bipolar transistor Q4 is grounded.
In this embodiment, the first bipolar transistor Q1 and the third bipolar transistor Q3 form a current mirror; the power supply voltage VDD, the second resistor R2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4 together determine the current flowing through the second resistor R2; the first bipolar transistor Q1 and the first capacitor C1 form a linearizer; the first resistor R1 is a ballast resistor; the second bipolar transistor Q2 is an additional diode-connected transistor.
Example 2A Power Amplifier
As shown in fig. 2, the present embodiment includes a power amplifying circuit and an active bias circuit for improving linearity of the power amplifier provided in embodiment 1, where an output terminal of the active bias circuit for improving linearity of the power amplifier is connected to a bias signal input terminal of the power amplifying circuit.
As shown in fig. 2, the power amplifying circuit includes a choke inductance L1, a power amplifying tube Q0, a second capacitor C2, and a third capacitor C3. One end of the second capacitor C2 is used as a radio frequency signal input end of the power amplifier, and the other end of the second capacitor C2 is used as an amplifying circuit bias signal input end on one hand and is connected with a base electrode of the power amplifier Q0 on the other hand; the emitter of the power amplifier tube Q0 is grounded, the collector of the power amplifier tube Q0 is connected with the power supply voltage VCC through the choke inductor L1 on the one hand, and is connected with one end of the third capacitor C3 on the other hand, and the other end of the third capacitor C3 serves as a radio frequency signal output end of the power amplifier.
The working principle of the embodiment is as follows: when the RF input signal RFin increases gradually, V of the power amplifier Q0 BE The potential will decrease and thus the V1 potential will also decrease. The decrease in V1 potential will cause the current I1 of the second bipolar transistor Q2 to decrease, and the decrease in I1 compensates for the change in I0. That is, due to the addition of the second bipolar transistor Q2, the offset of the working point of the power amplifier under a large signal is improved, and finally the linearity of the power amplifier is improved.
A comparison plot of normalized output signal amplitude versus input signal at 3.5GHz is shown in fig. 3. As can be seen from the figure, the power amplifier using the bias circuit with the second bipolar transistor Q2 has less amplitude-amplitude distortion than the power amplifier using the bias circuit without the second bipolar transistor Q2 when the input signal is greater than 10 dBm.
Fig. 4 shows a comparison of normalized output signal phase versus input signal at 3.5 GHz. As can be seen from the figure, the power amplifier using the bias circuit with the second bipolar transistor Q2 has less amplitude-phase distortion than the power amplifier using the bias circuit without the second bipolar transistor Q2 when the input signal is greater than 10 dBm.
Fig. 5 shows a comparison curve of the output 1dB compression point power versus frequency for this embodiment. As can be seen from the figure, the power amplifier using the bias circuit with the second bipolar transistor Q2 has a larger output 1dB compression point power than the power amplifier using the bias circuit without the second bipolar transistor Q2.
Fig. 6 shows a comparison curve of PAE with frequency when ldB compressed point power is output according to the present embodiment. As can be seen from the figure, the power amplifier using the bias circuit with the second bipolar transistor Q2 has a higher power added efficiency PAE than the power amplifier using the bias circuit without the second bipolar transistor Q2.
Claims (4)
1. The active bias circuit for improving the linearity of the power amplifier comprises a reference branch and a linearization circuit, wherein the output end of the reference branch is connected with the input end of the linearization circuit, and the output end of the linearization circuit is used as the output end of the active bias circuit for improving the linearity of the power amplifier;
the linearization circuit comprises a first bipolar transistor, a first capacitor and a first resistor; the base electrode of the first bipolar transistor is grounded through a first capacitor on the one hand and is used as an input end of the linearization circuit on the other hand, the collector electrode of the first bipolar transistor is connected with a power supply voltage, the emitter electrode of the first bipolar transistor is connected with one end of a first resistor, and the other end of the first resistor is used as an output end of the linearization circuit;
the method is characterized in that: the linearization circuit further includes a diode-connected second bipolar transistor; the base electrode and the collector electrode of the second bipolar transistor are connected with the emitter electrode of the first bipolar transistor and the common end of the first resistor after being short-circuited, and the emitter electrode of the second bipolar transistor is grounded.
2. The active bias circuit of claim 1, wherein the active bias circuit is configured to increase linearity of the power amplifier: the reference branch comprises a second resistor, a third diode-connected bipolar transistor and a fourth diode-connected bipolar transistor;
the collectors of the third bipolar transistor and the fourth bipolar transistor are respectively connected with the bases of the third bipolar transistor and the fourth bipolar transistor;
the common end of the collector electrode and the base electrode of the third bipolar transistor is connected with the power supply voltage through a second resistor on one hand and is used as the output end of the reference branch circuit on the other hand;
the emitter of the third bipolar transistor is connected with the common end of the collector and the base of the fourth bipolar transistor, and the emitter of the fourth bipolar transistor is grounded.
3. A power amplifier comprising a power amplifying circuit, and further comprising an active bias circuit for improving linearity of the power amplifier according to claim 1 or 2, wherein an output terminal of the active bias circuit for improving linearity of the power amplifier is connected to a bias signal input terminal of the power amplifying circuit.
4. A power amplifier according to claim 3, characterized in that: the power amplifying circuit comprises a choke inductor, a power amplifying tube, a second capacitor and a third capacitor;
one end of the second capacitor is used as a radio frequency signal input end of the power amplifier, and the other end of the second capacitor is used as an amplifying circuit bias signal input end on one hand and is connected with a base electrode of the power amplifier tube on the other hand;
the emitter of the power amplifier tube is grounded, the collector of the power amplifier tube is connected with the power supply voltage through a choke inductor on one hand, and is connected with one end of a third capacitor on the other hand, and the other end of the third capacitor is used as a radio frequency signal output end of the power amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322505226.4U CN220775788U (en) | 2023-09-15 | 2023-09-15 | Active bias circuit for improving linearity of power amplifier and corresponding power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322505226.4U CN220775788U (en) | 2023-09-15 | 2023-09-15 | Active bias circuit for improving linearity of power amplifier and corresponding power amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220775788U true CN220775788U (en) | 2024-04-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322505226.4U Active CN220775788U (en) | 2023-09-15 | 2023-09-15 | Active bias circuit for improving linearity of power amplifier and corresponding power amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220775788U (en) |
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2023
- 2023-09-15 CN CN202322505226.4U patent/CN220775788U/en active Active
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