阅读说明：本技术 一种带宽可调式f类功率放大器 (Bandwidth-adjustable F-type power amplifier ) 是由 彭林 章国豪 唐浩 黄国宏 于 2020-06-10 设计创作，主要内容包括：本发明公开了一种带宽可调式F类功率放大器,包括晶体管、谐波控制电路、寄生补偿电路、带宽可调的基波匹配网络和负载,谐波控制电路包括输入电压、短路传输线和开路传输线,短路传输线并联开路传输线形成偶次谐波短路电路,输入电压与偶次谐波短路电路串联；通过在谐波控制电路中将短路传输线和开路传输线进行并联形成偶次谐波短路电路,能够使得谐波控制电路只针对偶次谐波起作用,基波与奇次谐波处由于呈现开路而不会对电路产生影响,提高功率放大器的效率,此外,通过在谐波控制电路和带宽可调的基波匹配网络之间串联一个寄生补偿电路,能补偿掉C<Sub>out</Sub>对三次谐波阻抗的影响,实现很好的三次谐波开路状态,确保了F类功率放大器的高效率特性。(The invention discloses a bandwidth-adjustable F-type power amplifier, which comprises a transistor, a harmonic control circuit, a parasitic compensation circuit, a bandwidth-adjustable fundamental wave matching network and a load, wherein the harmonic control circuit comprises input voltage, a short circuit transmission line and an open circuit transmission line; the short circuit transmission line and the open circuit transmission line are connected in parallel in the harmonic control circuit to form an even harmonic short circuit, so that the harmonic control circuit only acts on even harmonics, the fundamental wave and the odd harmonics are not influenced by the circuit due to the open circuit, the efficiency of the power amplifier is improved, in addition, a parasitic compensation circuit is connected in series between the harmonic control circuit and the bandwidth-adjustable fundamental wave matching network, and C can be compensated out The influence on the third harmonic impedance realizes a good third harmonic open circuit state, and ensures F-type power amplifierHigh efficiency characteristics of the amplifier.)

1. The utility model provides a bandwidth-adjustable F class power amplifier, includes transistor, harmonic control circuit (1), parasitic compensating circuit (2), bandwidth adjustable fundamental wave matching network (3) and load (4), its characterized in that, the input of harmonic control circuit (1) with the drain output of transistor is connected, the output of harmonic control circuit (1) with the input of parasitic compensating circuit (2) is connected, the output of parasitic compensating circuit (2) with the input of bandwidth adjustable fundamental wave matching network (3) is connected, the output of bandwidth adjustable fundamental wave matching network (3) with load (4) are connected, harmonic control circuit (1) includes input voltage, short circuit transmission line (11) and open circuit transmission line (12), short circuit transmission line (11) connect in parallel open circuit transmission line (12) forms even harmonic short circuit, the input voltage is connected in series with the even harmonic short circuit.

2. A bandwidth-tunable class-F power amplifier according to claim 1, characterized in that the short-circuit transmission line (11) has a length equal to one-eighth of the fundamental wavelength λ, the open-circuit transmission line (12) has a length equal to one-eighth of the fundamental wavelength λ, and the short-circuit transmission line (11) and the open-circuit transmission line (12) both have an impedance Z₀。

3. A bandwidth adjustable class-F power amplifier according to claim 2, wherein the bandwidth adjustable fundamental matching network (3) comprises a first inductor (31), a second inductor (32), a first capacitor (33) and a second capacitor (34), a first end of the first inductor (31) and a first end of the second inductor (32) form a common terminal and are connected to the output terminal of the parasitic compensation circuit (2), a second end of the first inductor (31) is connected to a first end of the first capacitor (33), a second end of the second inductor (32) is connected to a first end of the second capacitor (34), and a second end of the first capacitor (33) and a second end of the second capacitor (34) form a common terminal ground.

4. A bandwidth adjustable class F power amplifier according to claim 3, wherein said harmonic control circuit (1) further comprises a third capacitor (13), a first end of said third capacitor (13) is connected to an input voltage of said harmonic control circuit (1), and a second end of said third capacitor (13) is connected to ground.

5. The adjustable bandwidth class-F power amplifier according to claim 4, further comprising a fourth capacitor (5), wherein a first end of the fourth capacitor (5) is connected to the output end of the adjustable bandwidth fundamental matching network (3), and a second end of the fourth capacitor (5) is connected to the load (4).

6. The adjustable bandwidth class-F power amplifier of claim 5, wherein the parasitic compensation circuit (2) is a parasitic compensation strip having an impedance of Z₀The electrical length of the parasitic compensation strip line is calculated by the following formula:

where θ is the electrical length of the parasitic compensation strip, ω is the fundamental angular frequency, C_outIs the equivalent output parasitic capacitance of the transistor.

Technical Field

The invention relates to the technical field of wireless communication power amplifiers, in particular to a bandwidth-adjustable F-type power amplifier.

Background

The power amplifier is used as an important front-end device in a wireless communication system, and the power amplifier amplifies a modulated frequency band signal to a required power value by using direct-current energy provided by a power supply and sends the signal to an antenna for transmission, so that a receiver in a certain area can receive a satisfactory signal level, and the quality of the design directly influences the whole circuit system.

In the prior art, the class F output matching network can adopt LC lumped elements, transmission lines or a mixture of the LC lumped elements according to the frequency range of the application, and the hybrid structure is generally the optimal choice for considering performance, volume and cost factors for the Sub-6GHz band currently used for mobile communications, as shown in fig. 1, the class F power amplifier is tuned to the carrier frequency by a parallel LC oscillation loop (L0-C0), so that the class F power amplifier can equivalently realize numerous series odd-order harmonic oscillators at all frequencies outside the working bandwidth as short circuits, and the length of the transmission line is selected to be 1/4 of the carrier wavelength λ, so that the situations of even-order harmonic short circuit and odd-order harmonic open circuit can be seen at the drain of the transistor, thereby realizing output current, and output current, The shaping of the voltage waveform ideally presents half sine wave current and square wave voltage with peak-peak value of 2VDD, and no overlapping part exists between the half sine wave current and the square wave voltage, which means that no energy is lost on the power tube, and 100% conversion efficiency can be realized.

However, the conventional class F power amplifier has the following disadvantages: (1) in a high frequency environment, part of harmonic components can pass through the parasitic capacitance C_outLeakage, thereby affecting the state of odd harmonic open circuit and causing the reduction of efficiency; (2) the actual transistors all contain a parasitic output capacitance C_outThe fundamental impedance is shifted.

Disclosure of Invention

In view of this, the present invention provides a bandwidth-adjustable F-type power amplifier, which can solve the defects of the existing F-type power amplifier, such as the influence on the odd harmonic open circuit state and the deviation of the fundamental wave impedance.

The technical scheme of the invention is realized as follows:

the utility model provides a F class power amplifier with adjustable bandwidth, includes transistor, harmonic control circuit, parasitic compensating circuit, bandwidth adjustable fundamental wave matching network and load, harmonic control circuit's input with the drain output end of transistor is connected, harmonic control circuit's output with parasitic compensating circuit's input is connected, parasitic compensating circuit's output with bandwidth adjustable fundamental wave matching network's input is connected, bandwidth adjustable fundamental wave matching network's output with the load is connected, harmonic control circuit includes input voltage, short circuit transmission line and opens the way the transmission line, the short circuit transmission line is parallelly connected open the transmission line and form even harmonic short circuit, input voltage with even harmonic short circuit establishes ties.

As a further alternative of the bandwidth-tunable class-F power amplifier, the short-circuited transmission line has a length equal to one-eighth of the fundamental wavelength λ, the open-circuited transmission line has a length equal to one-eighth of the fundamental wavelength λ, and the short-circuited transmission line and the open-circuited transmission line both have impedances Z₀。

As a further alternative of the bandwidth-adjustable class F power amplifier, the bandwidth-adjustable fundamental matching network includes a first inductor, a second inductor, a first capacitor, and a second capacitor, where a common terminal of a first end of the first inductor and a first end of the second inductor is connected to the output terminal of the parasitic compensation circuit, a second end of the first inductor is connected to a first end of the first capacitor, a second end of the second inductor is connected to a first end of the second capacitor, and a common terminal of a second end of the first capacitor and a second end of the second capacitor is grounded.

As a further alternative of the bandwidth-adjustable class-F power amplifier, the harmonic control circuit further includes a third capacitor, a first end of the third capacitor is connected to the input voltage of the harmonic control circuit, and a second end of the third capacitor is grounded.

As a further alternative of the bandwidth-adjustable class-F power amplifier, the class-F power amplifier further includes a fourth capacitor, a first end of the fourth capacitor is connected to the output end of the bandwidth-adjustable fundamental wave matching network, and a second end of the fourth capacitor is connected to the load.

As a further alternative of the bandwidth adjustable class F power amplifier, the parasitic compensation circuit is a parasitic compensation strip line with impedance Z₀The electrical length of the parasitic compensation strip line is calculated by the following formula:

where θ is the electrical length of the parasitic compensation strip, ω is the fundamental angular frequency, C_outIs the equivalent output parasitic capacitance of the transistor.

The invention has the beneficial effects that: through carry out the parallelly connected even harmonic short circuit that forms of short circuit transmission line and open circuit transmission line in harmonic control circuit, can make harmonic control circuit only act on even harmonic, and fundamental wave and odd harmonic department can not exert an influence to the circuit owing to appear opening a way to improve power amplifier's efficiency, in addition, through establishing ties a parasitic compensation circuit between harmonic control circuit and bandwidth adjustable fundamental wave matching network, can compensate C_outThe influence on the third harmonic impedance realizes a good third harmonic open circuit state, and ensures the high efficiency characteristic of the F-type power amplifier.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic circuit diagram of a conventional class F power amplifier control transistor drain;

FIG. 2 is a schematic circuit diagram of a bandwidth adjustable class-F power amplifier according to the present invention;

FIG. 3 is a schematic diagram of an even harmonic short circuit in a bandwidth adjustable class F power amplifier according to the present invention;

FIG. 4 shows a bandwidth-adjustable class-F power amplifier of the present invention₂-C₂The series resonator is equivalent to a capacitor C_eqA circuit schematic of (a);

FIG. 5 is a schematic diagram of a bandwidth adjustable class-F power amplifier according to the present invention, in which a first inductor in a pi-shaped matching network is properly divided into two L-shaped circuit diagrams facing each other;

description of reference numerals: 1. a harmonic control circuit; 2. a parasitic compensation circuit; 3. a bandwidth-adjustable fundamental wave matching network; 4. a load; 5. a fourth capacitor; 11. a short-circuit transmission line; 12. an open transmission line; 13. a third capacitor; 31. a first inductor; 32. a second inductor; 33. a first capacitor; 34. a second capacitance.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-3, a bandwidth adjustable class F power amplifier includes transistors, a harmonic control circuit 1, a parasitic compensation circuit 2, a bandwidth adjustable fundamental matching network 3 and a load 4, the input end of the harmonic control circuit 1 is connected with the drain electrode output end of the transistor, the output end of the harmonic control circuit 1 is connected with the input end of the parasitic compensation circuit 2, the output end of the parasitic compensation circuit 2 is connected with the input end of the bandwidth-adjustable fundamental wave matching network 3, the output end of the bandwidth-adjustable fundamental wave matching network 3 is connected with the load 4, the harmonic control circuit 1 comprises an input voltage, a short circuit transmission line 11 and an open circuit transmission line 12, the short circuit transmission line 11 is connected with the open circuit transmission line 12 in parallel to form an even harmonic short circuit, and the input voltage is connected with the even harmonic short circuit in series.

In the present embodiment, the even harmonic short circuit is formed by connecting the short circuit transmission line 11 and the open circuit transmission line 12 in parallel in the harmonic control circuit, so that the harmonic control circuit can only act on the even harmonic, and the fundamental wave and the odd harmonic do not affect the circuit due to the open circuit, thereby improving the efficiency of the power amplifier, and in addition, C can be compensated by connecting a parasitic compensation circuit 2 in series between the harmonic control circuit 1 and the fundamental wave matching network 3 with adjustable bandwidth_outThe influence on the third harmonic impedance realizes a good third harmonic open circuit state, and ensures the high efficiency characteristic of the F-type power amplifier.

Preferably, the short-circuit transmission line 11 has a length equal to one-eighth of the fundamental wavelength λ, the open-circuit transmission line 12 has a length equal to one-eighth of the fundamental wavelength λ, and the short-circuit transmission line 11 and the open-circuit transmission line 12 each have an impedance Z₀。

In the present embodiment, the lengths of the short-circuit transmission line 11 and the open-circuit transmission line 12 are set to be one eighth of the fundamental wavelength λ, and the impedances of the short-circuit transmission line 11 and the open-circuit transmission line 12 are set to be Z₀TL in FIG. 3 can be obtained according to the stub characteristic equation when the load is open or short-circuited₁And TL₂The input impedance at the node X is Z₁And Z₂And calculating Z₁And Z₂Impedance after parallel connection, wherein Z₁And Z₂Respectively as follows:

Z₁＝jZ₀tan(θ)

where θ represents the electrical length, which is related to the transmission line length:

thus, by Z₁And Z₂Z obtained in parallel_peakCan be expressed as:

since c ═ λ f, the above formula is further collated:

wherein f is₀Represents the fundamental operating frequency;

compared with the existing F-type power amplifier, the existing F-type power amplifier adopts a transmission line with the length of lambda/4, while the power amplifier adopts the transmission line with the length of lambda/8 which is arranged up and down symmetrically, the length of the transmission line is reduced by half compared with the length of lambda/4, and meanwhile, the short-circuit line TL₁The impedance equation is beneficial to providing better harmonic impedance peaking at a zero pole point, realizing a corresponding better terminal state and saving the cost;

in the figure, TL is shown₁Indicating a short-circuited transmission line 11, TL₂An open transmission line 12 is shown.

Preferably, the bandwidth-adjustable fundamental wave matching network 3 includes a first inductor 31, a second inductor 32, a first capacitor 33 and a second capacitor 34, a first end of the first inductor 31 and a first end of the second inductor 32 form a common terminal and are connected to the output terminal of the parasitic compensation circuit 2, a second end of the first inductor 31 is connected to a first end of the first capacitor 33, a second end of the second inductor 32 is connected to a first end of the second capacitor 34, and a second end of the first capacitor 33 and a second end of the second capacitor 34 form a common terminal and are grounded; wherein the first inductor 31 is L₁The second inductor 32 is L₂The first capacitor 33 is C₁The second capacitor 34 is C₂。

In this embodiment, the fundamental matching network is a pi-shaped fundamental matching network with adjustable bandwidth, that is, the pi-shaped matching network with adjustable bandwidth transforms a 50 Ω load to the fundamental optimal impedance R_optBut due to C_outAnd compensation strip line TL₃The effect of the formed single-stage-like L-shaped matching network is that the fundamental impedance at the B point is converted into Z_TAnd because TL is at this time₁～TL₃Can be determined from the foregoing, such that Z_TI.e. a determined value. In other words, the fundamental matching network is 50 Ω to Z to complete in consideration of the parasitic capacitance acting on the compensation strip line of the present invention_TConjugate value Z_T ^*And (4) transforming. At fundamental frequency omega₀Lower, L₂-C₂The series resonator can be equivalent to a capacitor C_eqWhich is related to L₁、C₁Together form a pi-shaped matching network, as shown in FIG. 4;

for simplicity, assume Z_T ^*Is a pure resistor R_TWe can match the series inductance L in the pi shape₁Properly divided into two parts, the network as a whole can be viewed as two face-to-face L-shaped circuits, as shown in fig. 5;

so-called "proper" will result in two L-shaped circuits having different quality factors, assuming Q on the left, a on the right, and Q > a, so that the quality factor of the pi-shaped network will be determined by the maximum of the quality factors in the sub-L-shaped circuits, i.e. Q, and in addition, the quality factor Q of the network has a relation to the bandwidth BW:

at a known operating frequency f₀In this case, the bandwidth of the matching network will depend on Q, and after the designer selects a suitable Q value according to the specification, the parameters of all the elements in the network can be determined according to the following equation:

when the complex impedance needs to be converted, the calculation formula becomes very complex, and the auxiliary design can be carried out by means of a Smith chart and an equal Q line;

furthermore, a series resonator is formed by the second inductance 32 and the second capacitance 34, by which resonance occurs at 3f₀Thereby causing point B in FIG. 2 to exhibit a third harmonic short circuit, with the aid of parasitic compensation strip TL₃And transistor output parasitic capacitance C_outThe impedance transformation in (a) in fig. 2 achieves a third harmonic open circuit state, thereby enabling the drain efficiency of the amplifier to reach 80%.

It should be noted that, considering that ideal harmonic impedance conditions cannot be realized in actual circuit design, when the harmonic control network includes 3-order and 4-order harmonics, the drain efficiency of the amplifier can reach 80%, and the inclusion of higher-order harmonic components not only increases the circuit design difficulty and increases power loss, but also has very limited effect on efficiency improvement, so that in order to keep the simple and easy feasibility of the whole output matching network, the invention only controls the utilization of odd-order harmonics to 3-order; in addition, compared with the existing scheme, the invention integrates the third harmonic control circuit into the fundamental wave matching network, thereby realizing the required fundamental wave impedance transformation, achieving the characteristic of a third harmonic short circuit state at a B point, and simultaneously adjusting the bandwidth.

Preferably, the harmonic control circuit 1 further includes a third capacitor 13, a first end of the third capacitor 13 is connected to the input voltage of the harmonic control circuit 1, and a second end of the third capacitor 13 is grounded.

In this embodiment, the third capacitor 13 is disposed in the harmonic control circuit 1, so as to bypass to the ground, and the capacitance value of the bypass capacitor is selected to be larger so that the impedance matching network is not substantially affected.

Preferably, the class F power amplifier further includes a fourth capacitor 5, a first end of the fourth capacitor 5 is connected to the output end of the bandwidth-adjustable fundamental wave matching network 3, and a second end of the fourth capacitor 5 is connected to the load 4.

In this embodiment, the fourth capacitor 5 is disposed between the bandwidth-adjustable fundamental matching network 3 and the load 4, so as to perform a dc blocking function.

Preferably, in a further alternative of the bandwidth-adjustable class-F power amplifier, the parasitic compensation circuit 2 is a parasitic compensation strip line, and the parasitic compensation strip line has an impedance Z₀The electrical length of the parasitic compensation strip line is calculated by the following formula:

where θ is the electrical length of the parasitic compensation strip, ω is the fundamental angular frequency, C_outIs the equivalent output parasitic capacitance of the transistor.

In this embodiment, the parasitic parameter C of the transistor_outObtaining the proper characteristic impedance Z in a device data manual provided by a manufacturer₀Rear, TL₃The electrical length of the electrode is determined, and the invention only passes through the TL₃Adjustment of electrical length to compensate for C drop_outThe method is simple and effective, and the initial value is quickly determined by means of an intuitive calculation formula, so that the engineering design efficiency is ensured.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.