CN219740329U - Circuit for improving gain flatness of ultra-wideband low frequency power amplifier - Google Patents
Circuit for improving gain flatness of ultra-wideband low frequency power amplifier Download PDFInfo
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- CN219740329U CN219740329U CN202321181640.8U CN202321181640U CN219740329U CN 219740329 U CN219740329 U CN 219740329U CN 202321181640 U CN202321181640 U CN 202321181640U CN 219740329 U CN219740329 U CN 219740329U
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- 238000004804 winding Methods 0.000 abstract description 7
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Abstract
The utility model relates to a circuit for improving gain flatness of an ultra-wideband low-frequency power amplifier, which comprises an RC frequency-selecting circuit, an alternating current negative feedback circuit and a paranoid circuit, wherein the RC frequency-selecting circuit is connected with a signal input end and is used for selecting signals in a specific frequency range and filtering signals of other frequencies; the alternating current negative feedback circuit is connected to the output end of the RC frequency selection circuit, receives the signal selected by the RC frequency selection circuit and is used for controlling gain and increasing bandwidth of the signal; and the paranoid circuit is arranged at the back of the alternating current negative feedback circuit, receives signals output by the alternating current negative feedback circuit, and is used for providing required working voltage for the alternating current negative feedback circuit and filtering stray signals brought by a power supply. The circuit is improved aiming at a common broadband power amplifier gain equalization circuit, and the stability of the amplifier can be improved through a winding inductance alternating current negative feedback technology, so that the circuit debugging is simplified.
Description
Technical Field
The utility model relates to the technical field of radio frequency power amplifiers, and discloses an ultra-wideband low-frequency Power Amplifier (PA) gain flatness improving circuit based on winding inductance alternating current negative feedback.
Background
Ultra wideband low frequency power amplifiers have very important applications in electronic warfare systems, secure communications, radar and broadband test systems, which have also become a very popular research direction in recent years, and it is difficult to achieve good gain flatness over a wide bandwidth due to the-6 dB degradation of the gain per octave of the transistors.
The prior art for improving the gain flatness generally adopts an RLC series-parallel pi-type network to improve the flatness. As shown in fig. 1, the equalization characteristic of high-end insertion loss and low-end insertion loss is realized by a high-pass filter formed by parallel connection of R1 and C1, the depth of the entire equalization curve is widened by the 'low-frequency resistance and high-frequency' characteristic of the inductors L1 and L2, and the value of the feedback resistors R2 and R3 is used for adjusting the equalization bandwidth. Thereby achieving the effect of improving the in-band gain flatness of the band power amplifier. The circuit adopts passive discrete devices, so the circuit has the advantages of low cost, stable performance, strong impact resistance and interference resistance and the like.
In practical circuits, manufacturing process limitations are due. Each device has errors in actual self inductance capacitance resistance value, and the number of discrete devices in the circuit is large. Each device value needs to be changed multiple times in specific circuit debugging to achieve the required equalization effect. The circuit is troublesome to debug, and the standing wave difference of the input and output ports of the circuit is easy to cause nonlinear distortion caused by mismatch between all stages. It is difficult to realize the later upgrading and reconstruction.
Disclosure of Invention
The utility model aims to: an improved ultra-wideband low frequency Power Amplifier (PA) gain flatness circuit based on wound inductor ac negative feedback is provided to solve the above problems of the prior art.
The technical scheme is as follows: an improved ultra wideband low frequency Power Amplifier (PA) gain flatness circuit based on wound inductor ac negative feedback, comprising:
the RC frequency selecting circuit is connected with the signal input end and is used for selecting signals in a specific frequency range and filtering out signals of other frequencies;
the alternating current negative feedback circuit is connected to the output end of the RC frequency selection circuit, receives the signal selected by the RC frequency selection circuit and is used for controlling gain and increasing bandwidth of the signal;
and the paranoid circuit is arranged at the back of the alternating current negative feedback circuit, receives signals output by the alternating current negative feedback circuit, and is used for providing required working voltage for the alternating current negative feedback circuit and filtering stray signals brought by a power supply.
According to one aspect of the utility model, the RC frequency selective circuit includes a blocking capacitor and a high pass filter.
According to one aspect of the utility model, the high pass filter is comprised of a resistor in parallel with a capacitor.
According to one aspect of the utility model, the ac negative feedback circuit includes a resistor, a capacitor, an inductor, and an amplifier.
According to one aspect of the utility model, the resistor, capacitor, inductor are connected in series between the gate and drain of the amplifier.
According to one aspect of the utility model, the inductor is a wound inductor.
According to one aspect of the utility model, the paranoid circuit includes a blocking capacitor, an inductor, and three capacitors.
According to one aspect of the utility model, the three capacitors are connected in parallel.
According to one aspect of the utility model, it comprises:
a fifth capacitor C5 connected to the input signal terminal,
a high-pass filter connected in series with the fifth capacitor C5 and composed of a seventh capacitor C7 and a second resistor R2 in parallel,
an amplifier U1 connected in series with the high pass filter, the amplifier comprising 4 ports, a first port being connected to the input signal as the gate of the amplifier and the high pass filter, a third port being connected to the output signal as the drain of the amplifier, the second and fourth ports being connected to ground,
an alternating current negative feedback core circuit which is connected with the amplifier U1 in parallel and is formed by connecting a first inductor L1, a first resistor R1 and a fourth capacitor C4 in series,
a sixth capacitor C6 connected in series with the drain electrode of the amplifier U1, the other end of the sixth capacitor C6 is connected with the output signal end,
the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected between the power supply VCC and the grounding end, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected in parallel, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected in series with the second inductor L2 to form a peripheral paranoid circuit of the amplifier U1, and one end of the peripheral paranoid circuit is connected between the drain electrode of the amplifier U1 and the sixth capacitor C6.
The beneficial effects are that: according to the utility model, the circuit is optimally designed, and an alternating current negative feedback circuit with a winding inductance and a series resistance capacitance is adopted on the basis of the original RC high-pass filtering characteristic, so that the stability of the amplifier can be increased, the standing wave of an input/output port of the amplifier is improved, nonlinear distortion is reduced, noise in a feedback loop is inhibited, the depth of an equilibrium curve can be regulated by regulating the position and the resistance of an inductance coil, the circuit structure is simplified, the debugging flexibility is increased, and the buried foundation is improved for the subsequent upgrading.
Drawings
Fig. 1 is a circuit diagram of RLC series-parallel equalization.
Fig. 2 is a functional block diagram of the present technology.
Fig. 3 is a schematic circuit diagram of the present technology.
Description of the embodiments
Ultra wideband low frequency power amplifiers have very important applications in electronic warfare systems, secure communications, radar and broadband test systems, which have also become a very popular research direction in recent years, and it is difficult to achieve good gain flatness over a wide bandwidth due to the-6 dB degradation of the gain per octave of the transistors.
In the prior art, the flatness of gain is improved by adopting an RLC series-parallel pi-type network, as shown in fig. 1, the equalization characteristics of large insertion loss at the low end and small insertion loss at the high end are realized by a high-pass filter formed by connecting R1 and C1 in parallel, the whole equalization curve depth is widened by the high-frequency characteristic of the low-frequency resistance of the inductors L1 and L2, and the equalization bandwidth is adjusted by the values of the feedback resistors R2 and R3. Thereby achieving the effect of improving the in-band gain flatness of the band power amplifier. The circuit adopts passive discrete devices, so the circuit has the advantages of low cost, stable performance, strong impact resistance and interference resistance and the like. In practical circuits, manufacturing process limitations are due. Each device has errors in actual self inductance capacitance resistance value, and the number of discrete devices in the circuit is large. Each device value needs to be changed multiple times in specific circuit debugging to achieve the required equalization effect. The circuit is troublesome to debug, and the standing wave difference of the input and output ports of the circuit is easy to cause nonlinear distortion caused by mismatch between all stages. It is difficult to realize the later upgrading and reconstruction.
According to the utility model, through the optimal design of the circuit, an alternating current negative feedback circuit with a winding inductance and a series resistance capacitance is adopted on the basis of the original RC high-pass filtering characteristic. As shown in fig. 2, the method specifically includes:
and the RC frequency selecting circuit is connected with the signal input end and used for selecting signals in a specific frequency range and filtering signals of other frequencies.
The RC frequency selecting circuit comprises a blocking capacitor and a high-pass filter, wherein the high-pass filter is formed by connecting a resistor and a capacitor in parallel, and the RC is connected in parallel and has high-pass filter characteristics, so that the balance characteristics of large low-frequency insertion loss and small high-frequency insertion loss are generated.
And the alternating current negative feedback circuit is connected with the output end of the RC frequency selecting circuit, receives the signal selected by the RC frequency selecting circuit and is used for controlling gain and increasing bandwidth of the signal.
The alternating current negative feedback circuit comprises a resistor, a capacitor and an inductor and an amplifier, wherein the resistor, the capacitor and the inductor are connected in series between the grid electrode and the drain electrode of the amplifier, and the gain of the amplifier in the circuit is only related to the negative feedback resistor and is not related to the parameters of the whole FET. The smaller the resistance value of the feedback resistor, the smaller the amplifier gain and the greater the negative feedback depth. The inductance is characterized by high frequency of low frequency resistance, and the inductance value is reduced along with the reduction of the frequency, so that the degree of negative feedback of the circuit is deeper when the frequency is lower, the roll-off of gain along with the increase of the frequency can be better compensated, and the gain flatness of the amplifier is improved. Meanwhile, good input-output matching can be obtained in the whole bandwidth range, so that port standing waves are improved.
The first inductor L1 in the circuit is a winding inductor, and the inductance value can be changed by only changing the number of turns of the winding inductor and the tightness position of the coil in the subsequent debugging, so that the equalization depth in a band can be adjusted in real time.
And the paranoid circuit is arranged at the back of the alternating current negative feedback circuit, receives signals output by the alternating current negative feedback circuit, and is used for providing required working voltage for the alternating current negative feedback circuit and filtering stray signals brought by a power supply.
The paranoid circuit comprises a blocking capacitor, an inductor and three capacitors, wherein the three capacitors are connected in parallel.
As shown in fig. 3, a schematic diagram of the circuit is shown, specifically:
a fifth capacitor C5 connected to the input signal terminal,
a high-pass filter connected in series with the fifth capacitor C5 and composed of a seventh capacitor C7 and a second resistor R2 in parallel,
an amplifier U1 connected in series with the high pass filter, the amplifier comprising 4 ports, a first port being connected to the input signal as the gate of the amplifier and the high pass filter, a third port being connected to the output signal as the drain of the amplifier, the second and fourth ports being connected to ground,
an alternating current negative feedback core circuit which is connected with the amplifier U1 in parallel and is formed by connecting a first inductor L1, a first resistor R1 and a fourth capacitor C4 in series,
a sixth capacitor C6 connected in series with the drain electrode of the amplifier U1, the other end of the sixth capacitor C6 is connected with the output signal end,
the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected between the power supply VCC and the grounding end, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected in parallel, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected in series with the second inductor L2 to form a peripheral paranoid circuit of the amplifier U1, and one end of the peripheral paranoid circuit is connected between the drain electrode of the amplifier U1 and the sixth capacitor C6.
Wherein P1 and P2 are standard 50 ohm loads, the fifth capacitor C5 and the sixth capacitor C6 are blocking capacitors on the paths, and peripheral equipment is prevented from being damaged when direct current signals are generated on the circuits. The first capacitor C1, the second capacitor C2, the third capacitor C3 and the second inductor L2 form a peripheral paranoid circuit of the amplifier U1, so that the required working voltage is provided for the amplifier, and stray signals brought by a power supply are filtered. The seventh capacitor C7 and the second resistor R2 are connected in parallel and have high-pass filtering characteristics, so that the flatness in part of the band is improved. The fourth capacitor C4, the first resistor R1 and the first inductor L1 form an ac negative feedback core circuit. The fourth capacitor C4 is responsible for blocking the dc signal between the gate and the drain of the amplifier, and the values of the first resistor R1 and the first inductor L1 determine the gain and bandwidth of the entire amplifier. When the first resistor R1 is fixed, the degree of balance required on the circuit is adjusted by only changing the number of turns and the tightness of the coil of the first inductor L1.
The circuit is modified aiming at a common broadband power amplifier gain equalization circuit. The method not only keeps the advantages of low cost, stable performance, strong impact resistance and interference resistance of the RC frequency-selecting network, and the like. And by the winding inductance alternating current negative feedback technology, the stability of the amplifier can be improved, so that the circuit debugging is simplified. The stability of the amplifier is improved, so that the standing wave of the port between the input and the output is improved, and the input and output matching in the pass band of the amplifier is optimized.
The specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations of the utility model are not described in detail in order to avoid unnecessary repetition.
Claims (8)
1. A circuit for improving gain flatness of an ultra wideband low frequency power amplifier, comprising:
the RC frequency selecting circuit is connected with the signal input end and is used for selecting signals in a specific frequency range and filtering out signals of other frequencies;
the alternating current negative feedback circuit is connected to the output end of the RC frequency selection circuit and is connected with the power amplifier in parallel, and the alternating current negative feedback circuit receives the signal selected by the RC frequency selection circuit and is used for controlling gain and increasing bandwidth of the signal;
and the paranoid circuit is arranged at one end of the alternating current negative feedback circuit and the power amplifier, receives signals output by the alternating current negative feedback circuit, and is used for providing required working voltage for the alternating current negative feedback circuit and filtering stray signals brought by a power supply.
2. The circuit for improving gain flatness of an ultra wideband low frequency power amplifier of claim 1, wherein the RC frequency selective circuit comprises a dc blocking capacitor and a high pass filter.
3. A circuit for improving the gain flatness of an ultra wideband low frequency power amplifier as claimed in claim 2, wherein the high pass filter is comprised of a resistor in parallel with a capacitor.
4. A circuit for improving gain flatness of an ultra wideband low frequency power amplifier according to claim 1, characterized in that the ac negative feedback circuit comprises a resistor, a capacitor, an inductor and an amplifier, the resistor, the capacitor, the inductor being connected in series between the gate and the drain of the amplifier.
5. The circuit of claim 4, wherein the inductor is a wound inductor.
6. The circuit of claim 1, wherein the paranoid circuit comprises a dc blocking capacitor, an inductor and three capacitors.
7. The circuit for improving gain flatness of an ultra wideband low frequency power amplifier of claim 6, wherein the three capacitors are connected in parallel.
8. The circuit for improving gain flatness of an ultra wideband low frequency power amplifier of claim 1, comprising:
a fifth capacitor C5 connected to the input signal terminal,
a high-pass filter connected in series with the fifth capacitor C5 and composed of a seventh capacitor C7 and a second resistor R2 in parallel,
an amplifier U1 connected in series with the high pass filter, the amplifier comprising 4 ports, a first port being connected to the input signal as the gate of the amplifier and the high pass filter, a third port being connected to the output signal as the drain of the amplifier, the second and fourth ports being connected to ground,
an alternating current negative feedback core circuit which is connected with the amplifier U1 in parallel and is formed by connecting a first inductor L1, a first resistor R1 and a fourth capacitor C4 in series,
a sixth capacitor C6 connected in series with the drain electrode of the amplifier U1, the other end of the sixth capacitor C6 is connected with the output signal end,
the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected between the power supply VCC and the grounding end, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected in parallel, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are connected in series with the second inductor L2 to form a peripheral paranoid circuit of the amplifier U1, and one end of the peripheral paranoid circuit is connected between the drain electrode of the amplifier U1 and the sixth capacitor C6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321181640.8U CN219740329U (en) | 2023-05-17 | 2023-05-17 | Circuit for improving gain flatness of ultra-wideband low frequency power amplifier |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321181640.8U CN219740329U (en) | 2023-05-17 | 2023-05-17 | Circuit for improving gain flatness of ultra-wideband low frequency power amplifier |
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| Publication Number | Publication Date |
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| CN219740329U true CN219740329U (en) | 2023-09-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202321181640.8U Active CN219740329U (en) | 2023-05-17 | 2023-05-17 | Circuit for improving gain flatness of ultra-wideband low frequency power amplifier |
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| CN (1) | CN219740329U (en) |
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- 2023-05-17 CN CN202321181640.8U patent/CN219740329U/en active Active
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Denomination of utility model: A circuit for improving the gain flatness of ultra wideband low-frequency power amplifiers Effective date of registration: 20231220 Granted publication date: 20230922 Pledgee: Nanjing Bank Co.,Ltd. Nanjing North Branch Pledgor: Jiangsu hairuida Microelectronics Technology Co.,Ltd. Registration number: Y2023980072768 |