CN113315477A - Radio frequency amplifier and control method thereof - Google Patents
Radio frequency amplifier and control method thereof Download PDFInfo
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- CN113315477A CN113315477A CN202110521318.4A CN202110521318A CN113315477A CN 113315477 A CN113315477 A CN 113315477A CN 202110521318 A CN202110521318 A CN 202110521318A CN 113315477 A CN113315477 A CN 113315477A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
- H03F1/04—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in discharge-tube amplifiers
- H03F1/06—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in discharge-tube amplifiers to raise the efficiency of amplifying modulated radio frequency waves; to raise the efficiency of amplifiers acting also as modulators
- H03F1/07—Doherty-type amplifiers
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Abstract
The invention discloses a radio frequency amplifier and a control method thereof, comprising a first-stage amplifying circuit, a second-stage amplifying circuit and a bypass circuit; the first-stage amplification circuit is connected with the second-stage amplification circuit in series, the input end of the first-stage amplification circuit is connected with the signal input end, and the output end of the second-stage amplification circuit is connected with the signal output end and can be operated to control the on-off of the second-stage amplification circuit according to a circuit control signal applied to the second-stage amplification circuit; the bypass circuit is connected in parallel at two ends of the second-stage amplification circuit and is operable to control the on-off of the bypass circuit according to a bypass control signal applied to the bypass circuit, so that one of the second-stage amplification circuit and the bypass circuit is in conductive connection with the first-stage amplification circuit, the level of the circuit control signal is opposite to that of the bypass control signal, and the low-noise amplifier has the characteristics of high linearity and low noise coefficient under bypass and non-bypass working modes.
Description
Technical Field
The invention relates to the technical field of radio frequency, in particular to a radio frequency amplifier and a control method thereof.
Background
A Low Noise Amplifier (LNA) acts as the first active block of the receiver, whose noise figure almost determines the noise performance of the whole receiver. Meanwhile, the power of the signal received by the LNA varies widely, and different gains need to be provided to adapt to different signal powers. When the received signal power is small, it is necessary to provide a high gain to improve the sensitivity of the receiver, which requires the noise figure of the LNA to be as small as possible. When the received signal power is large, a low gain is required to avoid saturation of the subsequent circuit. In this way, although the LNA having the bypass function avoids saturation of the LNA or the subsequent circuit block in the case of a high-power input signal, the bypass-state LNA cannot provide a sufficiently large gain when receiving an input signal having a low power. That is, in most cases, the requirements of linearity, gain, matching, and noise figure cannot be satisfied under two operating states (bypass and access).
Disclosure of Invention
The embodiment of the invention provides a radio frequency amplifier and a control method thereof, which realize that the low-noise amplifier has the characteristics of high linearity and low noise coefficient under the bypass and non-bypass working modes.
An embodiment of the present invention provides a radio frequency amplifier, including: the circuit comprises a first-stage amplifying circuit, a second-stage amplifying circuit and a bypass circuit; the radio frequency amplifier is also provided with a signal input end used for inputting radio frequency signals and a signal output end used for being connected with a load;
the first-stage amplifying circuit is connected with the second-stage amplifying circuit in series, the input end of the first-stage amplifying circuit is connected with the signal input end, and the output end of the second-stage amplifying circuit is connected with the signal output end and can be operated to control the on-off of the second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit;
the bypass circuit is connected to two ends of the second-stage amplification circuit in parallel and is operable to control the on/off of the bypass circuit according to a bypass control signal applied to the bypass circuit, so that one of the second-stage amplification circuit and the bypass circuit is conductively connected with the first-stage amplification circuit, and the circuit control signal is opposite to the bypass control signal in level.
In some embodiments, the second stage amplifying circuit comprises a second stage amplifier and a first switch tube, and the circuit control signal comprises a first circuit control signal;
the input end of the second-stage amplifier is connected with the output end of the first-stage amplifying circuit, and the output end of the second-stage amplifier is connected with the output end of the second-stage amplifying circuit;
the first switch tube is connected to a power supply end of the second-stage amplifier and is operable to control the on-off of the first switch tube according to the first circuit control signal applied to the first switch tube, so that the on-off of the second-stage amplifier circuit is controlled.
In some embodiments, the second stage amplifying circuit further comprises a second switching tube, and the circuit control signal comprises a second circuit control signal;
the second switch tube is connected to the ground terminal of the second-stage amplifier and is operable to control the on/off of the second switch tube according to the second circuit control signal applied thereto, so as to control the on/off of the second-stage amplifier circuit.
In some embodiments, the second stage amplifying circuit further comprises a third switch tube, and the circuit control signal comprises a third circuit control signal;
the third switching tube is connected between the output end of the second-stage amplifier and the output end of the second-stage amplifying circuit and is operable to control the on-off of the third switching tube according to the third circuit control signal applied to the third switching tube, so that the on-off of the second-stage amplifying circuit is controlled.
In some embodiments, the first stage amplification circuit comprises a first stage amplifier and a first power-down control switch tube, and the second stage amplification circuit comprises a second power-down control switch tube;
the input end of the first-stage amplifier is connected with the signal input end, and the output end of the first-stage amplifier is connected with the output end of the first-stage amplifying circuit;
the first power-down control switch tube is connected to the grounding end of the first-stage amplifier, the second power-down control switch tube is connected between the second switch tube and the ground potential, and the first power-down control switch tube and the second power-down control switch tube can be operated to synchronously control the on-off of the first power-down control switch tube and the second power-down control switch tube according to power-down control signals loaded on the first power-down control switch tube and the second power-down control switch tube.
In some embodiments, the bypass circuit is formed by connecting a plurality of switch tubes in series in the same direction, and the gates of the switch tubes are controlled by the bypass control signal to control the on/off of the bypass circuit.
In some embodiments, the radio frequency amplifier comprises an input stage impedance matching circuit and an output stage impedance matching circuit;
the input stage impedance matching circuit comprises a first capacitor and a first inductor;
one end of the first capacitor is connected with the signal input end, and the other end of the first capacitor is connected with the first end of the first inductor; and the second end of the first inductor is connected with the input end of the first-stage amplifying circuit.
The output stage impedance matching circuit comprises a second capacitor, a third capacitor and a second inductor;
the second capacitor and the third capacitor are connected in series between the output end of the second-stage amplifying circuit and the signal output end; the second inductor is connected between the second capacitor and the third capacitor and to ground potential.
Another embodiment of the present invention correspondingly provides a method for controlling a radio frequency amplifier, which is suitable for the radio frequency amplifier, and the method includes:
controlling the on-off of the second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit;
according to a bypass control signal applied to a bypass circuit, the on-off of the bypass circuit is controlled, so that one of the second-stage amplification circuit and the bypass circuit is in conductive connection with the first-stage amplification circuit, and the level of the circuit control signal is opposite to that of the bypass control signal.
In some embodiments, when the rf amplifier is in the high gain mode, the circuit control signal is at a high level, the bypass control signal is at a low level, so that the bypass circuit is disconnected, and the second-stage amplifying circuit is conductively connected to the first-stage amplifying circuit, so that the input rf signal is amplified by the two-stage amplifying circuits;
when the radio frequency amplifier is in a low gain mode, the circuit control signal is at a low level, the bypass control signal is at a high level, so that the second-stage amplification circuit is disconnected, and the bypass circuit is in conductive connection with the first-stage amplification circuit, so that the input radio frequency signal flows out of the bypass circuit after passing through the first-stage amplification circuit to complete amplification.
In some embodiments, the method further comprises:
when the radio frequency amplifier is in a turn-off mode, when the power failure control signals loaded on the first power failure control switch tube and the second power failure control switch tube are at a low level, the first power failure control switch tube and the second power failure control switch tube are disconnected, so that the two stages of amplification circuits are disconnected.
Compared with the prior art, the radio frequency amplifier and the control method thereof disclosed by the embodiment of the invention comprise the following steps: the circuit comprises a first-stage amplifying circuit, a second-stage amplifying circuit and a bypass circuit; the radio frequency amplifier is also provided with a signal input end used for inputting radio frequency signals and a signal output end used for being connected with a load; the first-stage amplifying circuit is connected with the second-stage amplifying circuit in series, the input end of the first-stage amplifying circuit is connected with the signal input end, and the output end of the second-stage amplifying circuit is connected with the signal output end and can be operated to control the on-off of the second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit; the bypass circuit is connected to two ends of the second-stage amplification circuit in parallel and is operable to control the on/off of the bypass circuit according to a bypass control signal applied to the bypass circuit, so that one of the second-stage amplification circuit and the bypass circuit is conductively connected with the first-stage amplification circuit, and the circuit control signal is opposite to the bypass control signal in level. Thus, when the radio frequency amplifier is in a high gain mode, the bypass circuit is disconnected, the second-stage amplification circuit is connected with the first-stage amplification circuit in a conduction mode, so that the radio frequency signal is amplified after passing through the two-stage amplification circuit, and the circuit gain is the sum of the gains of the two-stage amplification circuit; when the radio frequency amplifier is in a low gain mode, the second-stage amplifying circuit is disconnected, the bypass circuit is in conductive connection with the first-stage amplifying circuit, so that radio frequency signals flow out of the bypass circuit after passing through the first-stage amplifying circuit to finish amplification, the circuit gain is only the gain of the first-stage amplifying circuit at the moment, the low noise amplifier has the characteristics of high linearity and low noise coefficient in bypass and non-bypass working modes, and the requirements of the linearity, the gain and the noise coefficient are met.
Drawings
FIG. 1 is a schematic diagram of a low noise amplifier according to the prior art;
fig. 2 is a schematic structural diagram of a radio frequency amplifier according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of an alternative embodiment of a radio frequency amplifier according to an embodiment of the present invention;
fig. 4 is a schematic diagram of an overall structure of a radio frequency amplifier according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a radio frequency amplifier according to an embodiment of the present invention;
fig. 6 is a flowchart illustrating a method for controlling a radio frequency amplifier according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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, a schematic diagram of a low noise amplifier according to the prior art is shown, in which a bypass path is connected in parallel to two ends of an amplifier, and the amplifier is connected in series between an input stage impedance matching circuit and an output stage impedance matching circuit. With this structure, the low noise amplifier has no gain after being in the bypass mode, i.e. the overall amplifier is bypassed. Although saturation of the lna or the post-stage circuit module under the condition of a high-power input signal is avoided, when the received power is not so high, the lna under the bypass state cannot provide enough gain, so that the requirements of linearity, gain, matching and noise coefficient cannot be met under two working states (bypass and non-bypass) mostly.
Therefore, referring to fig. 2, a schematic structural diagram of a radio frequency amplifier according to an embodiment of the present invention is shown, where the radio frequency amplifier includes: a first-stage amplifier circuit 11, a second-stage amplifier circuit 12, and a bypass circuit 13; the rf amplifier further has a signal input RFin for inputting an rf signal and a signal output for connection to a load 14;
the first stage amplifying circuit 11 is connected in series with the second stage amplifying circuit 12, an input end of the first stage amplifying circuit 11 is connected with the signal input end RFin, and an output end of the second stage amplifying circuit 12 is connected with the signal output end, and is operable to control the on/off of the second stage amplifying circuit 12 according to a circuit control signal applied to the second stage amplifying circuit 12;
the bypass circuit 13 is connected in parallel to two ends of the second-stage amplification circuit 12, and is operable to control the on/off of the bypass circuit 13 according to a bypass control signal applied to the bypass circuit 13, so that one of the second-stage amplification circuit 12 and the bypass circuit 13 is conductively connected to the first-stage amplification circuit 11, and the circuit control signal is opposite to the bypass control signal in level.
In the present invention, the rf amplifier is a two-stage amplifier cascade, but the rf amplifier may be a multi-stage amplifying circuit, and is not limited thereto. Meanwhile, only one stage of the two stages of amplifying circuits is connected with a bypass circuit in parallel (namely, the RF amplifier has a bypass function), so that the RF amplifier can have two gain modes, and the circuit has more flexibility. It should be noted that, in order to reduce noise and facilitate matching, the second-stage amplifying circuit 12 is designed as a bypass stage in the present invention, that is, the bypass circuit 13 is connected in parallel to two ends of the second-stage amplifying circuit 12. Alternatively, referring to fig. 3, it is a schematic structural diagram of an alternative embodiment of the radio frequency amplifier according to an embodiment of the present invention, and the first-stage amplifying circuit 11 may also be designed as a bypass stage, that is, the bypass circuit 13 is connected in parallel to two ends of the first-stage amplifying circuit 11.
The working principle of the radio frequency amplifier of the invention is as follows:
when the radio frequency amplifier is in a high gain mode, the circuit control signal is at a high level, the bypass control signal is at a low level, so that the bypass circuit 13 is disconnected, and the radio frequency amplifier is in a non-bypass working mode, the second-stage amplifying circuit 12 is in conductive connection with the first-stage amplifying circuit 11, so that the input radio frequency signal is amplified after passing through the two-stage amplifying circuits, and the circuit gain is the sum of the gains of the two-stage amplifying circuits;
when the radio frequency amplifier is in the low gain mode, the circuit control signal is at a low level, the bypass control signal is at a high level, so that the second-stage amplification circuit 12 is turned off (the second-stage amplification circuit 12 is bypassed), and in the bypass working mode, the bypass circuit 13 is in conductive connection with the first-stage amplification circuit 11, so that the input radio frequency signal flows out from the bypass circuit 13 after passing through the first-stage amplification circuit 11 to complete amplification, and at this time, the circuit gain is the gain of the first-stage amplification circuit 11.
The radio frequency amplifier provided by the embodiment of the invention comprises a first-stage amplifying circuit, a second-stage amplifying circuit and a bypass circuit; the radio frequency amplifier is also provided with a signal input end used for inputting radio frequency signals and a signal output end used for being connected with a load; the first-stage amplifying circuit is connected with the second-stage amplifying circuit in series, the input end of the first-stage amplifying circuit is connected with the signal input end, and the output end of the second-stage amplifying circuit is connected with the signal output end and can be operated to control the on-off of the second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit; the bypass circuit is connected to two ends of the second-stage amplification circuit in parallel and is operable to control the on/off of the bypass circuit according to a bypass control signal applied to the bypass circuit, so that one of the second-stage amplification circuit and the bypass circuit is conductively connected with the first-stage amplification circuit, and the circuit control signal is opposite to the bypass control signal in level. Thus, when the radio frequency amplifier is in a high gain mode, the bypass circuit is disconnected, the second-stage amplification circuit is connected with the first-stage amplification circuit in a conduction mode, so that the radio frequency signal is amplified after passing through the two-stage amplification circuit, and the circuit gain is the sum of the gains of the two-stage amplification circuit; when the radio frequency amplifier is in a low gain mode, the second-stage amplifying circuit is disconnected, the bypass circuit is in conductive connection with the first-stage amplifying circuit, so that radio frequency signals flow out of the bypass circuit after passing through the first-stage amplifying circuit to finish amplification, the circuit gain is only the gain of the first-stage amplifying circuit at the moment, the low noise amplifier has the characteristics of high linearity and low noise coefficient in bypass and non-bypass working modes, and the requirements of the linearity, the gain and the noise coefficient are met.
In some embodiments, referring to fig. 4, which is a schematic diagram of an overall structure of the radio frequency amplifier provided in an embodiment of the present invention, the second-stage amplifying circuit 12 includes a second-stage amplifier and a first switching tube M1, and the circuit control signal VHG includes a first circuit control signal VHG;
the input end of the second-stage amplifier is connected with the output end of the first-stage amplifying circuit 11, and the output end of the second-stage amplifier is connected with the output end of the second-stage amplifying circuit 12;
the first switch transistor M1, connected to the power supply terminal of the second-stage amplifier, is operable to control the on/off of the first switch transistor M1 according to the first circuit control signal VHG applied thereto, so as to control the on/off of the second-stage amplifier circuit 12.
In this embodiment, the power source terminal of the second-stage amplifier is connected to the first switch transistor M1, so that when the second-stage amplifier is bypassed, the first switch transistor M1 is turned off, thereby cutting off the operating current of the second-stage amplifier and reducing the power consumption. Specifically, the source of the first switch transistor M1 is connected to the power supply VDD2, the drain thereof is connected to the power supply terminal of the second stage amplifier, and the gate thereof receives the first circuit control signal to control the on/off of the first switch transistor M1. In addition, the gate of the first switching tube M1 is connected in series with a resistor R41, which can effectively prevent the switching tube from being broken down.
In some embodiments, referring to fig. 4, the second stage amplifying circuit 12 further includes a second switch M2, and the circuit control signal VHG includes a second circuit control signal VHG;
the second switch tube M2 is connected to the ground terminal of the second stage amplifier, and is operable to control the on/off of the second switch tube M2 according to the second circuit control signal applied thereto, so as to control the on/off of the second stage amplifier circuit 12.
In the present embodiment, referring to fig. 4, a second switch M2 is disposed at the ground terminal of the second-stage amplifier (i.e. the source of the common-source transistor of the second-stage amplifier), so that when the second-stage amplifier is bypassed, the second switch M2 is turned off, thereby preventing the rf signal from leaking to the second-stage amplifying circuit 12. Specifically, the source of the second switch transistor M2 is connected to the source of the common source transistor of the second stage amplifier, and the gate thereof receives the second circuit control signal VHG to control the on/off of the second switch transistor M2. In addition, the gate of the second switching tube M2 is connected in series with an isolation resistor R42.
In some embodiments, referring to fig. 4, the second stage amplifying circuit 12 further includes a third switch M3, and the circuit control signal VHG includes a third circuit control signal VHG;
the third switching tube M3 is connected between the output terminal of the second-stage amplifier and the output terminal of the second-stage amplifying circuit 12, and is operable to control the on/off of the third switching tube M3 according to the third circuit control signal VHG applied thereto, so as to control the on/off of the second-stage amplifying circuit 12.
In this embodiment, referring to fig. 4, a third switching tube M3 is disposed at the rf output end of the second-stage amplifier, so that when the second-stage amplifier is bypassed, the third switching tube M3 is turned off, thereby preventing the rf signal from leaking to the second-stage amplifying circuit 12. Specifically, the source of the third switching tube M3 is connected to the output end (connected to the signal output end) of the second stage amplifier circuit 12, the drain thereof is connected to the output end of the second stage amplifier, and the gate thereof receives the third circuit control signal VHG to control the on/off of the third switching tube M3. In addition, the grid electrode of the third switching tube is connected with a resistor R43 in series, so that the switching tube can be effectively prevented from being broken down.
In some embodiments, referring to fig. 4, the first stage amplifier circuit 11 includes a first stage amplifier and a first power-down control switch M41, and the second stage amplifier circuit 12 includes a second power-down control switch M42;
the input end of the first-stage amplifier is connected with the signal input end RFin, and the output end of the first-stage amplifier is connected with the output end of the first-stage amplifying circuit 12;
the first power-down control switch tube M41 is connected to the ground terminal of the first-stage amplifier, and the second power-down control switch tube M42 is connected between the second switch tube M2 and the ground potential, and is operable to synchronously control the on/off of the first power-down control switch tube M41 and the second power-down control switch tube M42 according to the power-down control signal VPD loaded on the first power-down control switch tube M41 and the second power-down control switch tube M42.
In this embodiment, the source of the first power-down control switch M41 is connected to the first stage amplifier, the drain thereof is connected to the ground potential, and the gate thereof is controlled by the power-down control signal VPD. The source of the second power-down control switch M42 is connected to the drain of the second switch M2, the drain thereof is connected to ground potential, and the gate thereof is controlled by the power-down control signal VPD. Therefore, the same power-down control signal VPD is received by the first power-down control switch tube M41 and the second power-down control switch tube M42 at the same time, so as to control the on/off of the respective switch tubes.
Specifically, when the power down control signal VPD is at a low level, the two-stage amplifier circuit is in an off mode (power down mode), and the first power down control switch M41 and the second power down control switch M42 are turned off, so that both the two-stage amplifier circuit are turned off. When the power-off control signal VPD is at a high level, the first power-off control switch tube M41 and the second power-off control switch tube M42 are turned on, and at this time, the first-stage amplifying circuit 11 is turned on, so as to control the circuit control signal. Furthermore, in the present invention, the first circuit control signal VHG, the second circuit control signal VHG and the third circuit control signal VHG have the same level, and the on/off of the second stage amplifying circuit 12 is synchronously controlled. When the rf amplifier is in the high gain mode, the power-down control signal VPD is at a high level (5V), the first power-down control switch M41 and the second power-down control switch M42 are turned on, the bypass control signal VLG is at a low level (-2.5V), the bypass circuit 13 is turned off, the first circuit control signal VHG, the second circuit control signal VHG and the third circuit control signal VHG are at a high level (5V), all the switches (i.e., the auxiliary transistors) at the power supply terminal, the ground terminal and the output terminal of the second stage amplifier are turned on, the second stage amplifier circuit 12 operates normally, the rf signal passes through the two stages amplifier to complete amplification, and the gain is the sum of the gains of the two stages amplifier. When the amplifier is in the low gain mode, the power-down control signal VPD is at a high level (5V), the first power-down control switch M41 and the second power-down control switch M42 are turned on, the bypass control signal VLG is at a high level (5V), the first circuit control signal VPD, the second circuit control signal VPD and the third circuit control signal VPD are at a low level (-2.5V), the bypass circuit is turned on, the auxiliary transistors are all turned off, the second-stage amplification circuit 12 is in an off state, the radio-frequency signal flows out from the bypass path after flowing through the first-stage amplifier to complete amplification, and the gain at this time is the gain of the first-stage amplifier.
In some embodiments, referring to fig. 4, the bypass circuit 13 is formed by connecting a plurality of switching tubes in series in the same direction, and the gates of the switching tubes are controlled by the bypass control signal VLG to control the on/off of the bypass circuit 13.
Illustratively, as shown in fig. 4, the bypass circuit 13 is formed by connecting 3 switching tubes in series in the same direction. Specifically, the source of the left switching transistor M51 is connected to the output terminal of the first-stage amplifier circuit 11, and the drain thereof is connected to the source of the middle switching transistor M52. The source of the switching transistor M53 on the right side is connected to the drain of the switching transistor M52 in the middle, and the drain thereof is connected to the output terminal of the second-stage amplifier circuit 12. The gates of the three switching tubes in the bypass circuit 13 are simultaneously controlled by a bypass control signal VLG to realize synchronous on-off, thereby controlling the on-off of the bypass circuit 13. In addition, the circuit control signal VHG is opposite in level to the bypass control signal VLG, such as when the circuit control signal VHG is high (5V), the bypass control signal VLG is low (-2.5V), and vice versa.
In some embodiments, referring to fig. 4, the rf amplifier includes an input stage impedance matching circuit 15 and an output stage impedance matching circuit 16;
the input stage impedance matching circuit 15 comprises a first capacitor C41 and a first inductor L41;
one end of the first capacitor C41 is connected to the signal input terminal RFin, and the other end is connected to the first end of the first inductor L41; a second end of the first inductor L41 is connected to the input end of the first stage amplifier circuit 11.
The output stage impedance matching circuit 16 comprises a second capacitor C42, a third capacitor C43 and a second inductor L42;
the second capacitor C42 and the third capacitor C43 are connected in series between the output end of the second stage amplifying circuit 12 and the signal output end; the second inductor L42 is connected between the second capacitor C42 and the third capacitor C43 and to ground potential.
Preferably, the rf amplifier uses a source degeneration inductor to implement input matching, wherein the first inductor L41 is a planar spiral inductor with optimized size. Specifically, the line width of the inner ring area of the planar spiral capacitor is narrow, and the distance is large, so that the electromagnetic loss is reduced; the outer ring area has wider line width and smaller space, so that the resistance loss is reduced, the noise coefficient can be effectively reduced on the whole, good input and output matching is realized, and the requirements of linearity, gain, matching and noise coefficient under two working states are met.
Based on the foregoing embodiments, in a preferred embodiment, referring to fig. 5, a specific structural schematic diagram of the radio frequency amplifier according to an embodiment of the present invention is shown, the radio frequency amplifier is a cascade structure of two stages of amplifying circuits, the two stages are coupled and connected through a dc blocking capacitor C53, and each stage of amplifying circuit is in a cascode configuration. The second-stage amplifying circuit 12 is designed as a stage with a bypass function, that is, the input end and the output end of the second-stage amplifying circuit 12 are connected in parallel with a bypass circuit 13 formed by connecting switching transistors in series, and a switching transistor is respectively connected in series with the source of the common source transistor in the cascode, the drain of the common gate transistor (the output end of the second-stage amplifier), and the power supply end (VDD2) of the second-stage amplifier, and a total of three switching transistors are used for assisting the bypass circuit, so that a better bypass effect is achieved.
Specifically, the first-stage amplifier is composed of a switch tube M61 and a switch tube M62. The source of the switching tube M61 is connected to the power supply VDD through the inductor L53, the drain thereof is connected to the source of the switching tube M62, the gate thereof is controlled by the signal Vbias1, the drain of the switching tube M62 is connected to the first power-down control switching tube M41 through the inductor, and the gate thereof is controlled by the signal Vbias 2. Similarly, the second stage amplifier is composed of a switch tube M71 and a switch tube M72. The source of the switching tube M71 is connected to the first switching tube M1 through the inductor L54, the drain thereof is connected to the source of the switching tube M72, the gate thereof is controlled by the signal Vbias3, the drain of the switching tube M72 is connected to the second switching tube M2, and the gate thereof is controlled by the signal Vbias 4. In addition, the grid electrode of the switch transistor forming the bypass circuit is connected with a bypass control signal VLG, the switch transistor is positioned at the power supply end and the source end of the common source tube of the second-stage amplifier, the grid electrodes of the three switch tubes at the output end are connected with a circuit control signal VHG, and the grid electrodes of the PowerDown transistors (power-down control switch tubes) positioned at the source ends of the common source tubes of the two amplifiers are connected with a power-down control signal VPD. Also, VHG and VLG are two opposite dc voltage control signals.
The input stage impedance matching circuit 15 is composed of two diodes D1 and D2 connected in series, a capacitor C51, and an inductor L51, the junction of the two diodes is connected between the signal input terminal and the capacitor C51, the capacitor C51 is connected in series with the inductor L51, and the inductor L51 is connected to the input terminal of the first stage amplifier circuit 11. The output stage impedance matching circuit 16 is composed of a capacitor C56, a capacitor C57, an inductor L55 and an inductor L56, wherein the capacitor C56, the inductor L55 and the inductor L56 are connected in series, the inductor L56 is connected with a signal output end, and the capacitor C57 is connected between the inductor L55 and the inductor L56.
Referring to fig. 6, which is a flowchart illustrating a method for controlling a radio frequency amplifier according to an embodiment of the present invention, the method for controlling a radio frequency amplifier is suitable for the radio frequency amplifier, and the method includes steps S601 to S602:
s601, controlling the on-off of a second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit;
s602, controlling the on-off of the bypass circuit according to a bypass control signal applied to the bypass circuit, so that one of the second-stage amplification circuit and the bypass circuit is in conductive connection with the first-stage amplification circuit, and the level of the circuit control signal is opposite to that of the bypass control signal.
In a specific embodiment, when the rf amplifier is in the high gain mode, the circuit control signal is at a high level, the bypass control signal is at a low level, so that the bypass circuit is turned off, and the second-stage amplification circuit is connected to the first-stage amplification circuit, so that the input rf signal is amplified by the two-stage amplification circuit;
when the radio frequency amplifier is in a low gain mode, the circuit control signal is at a low level, the bypass control signal is at a high level, so that the second-stage amplification circuit is disconnected, and the bypass circuit is in conductive connection with the first-stage amplification circuit, so that the input radio frequency signal flows out of the bypass circuit after passing through the first-stage amplification circuit to complete amplification.
In an embodiment, the method further comprises:
when the radio frequency amplifier is in a turn-off mode, when the power failure control signals loaded on the first power failure control switch tube and the second power failure control switch tube are at a low level, the first power failure control switch tube and the second power failure control switch tube are disconnected, so that the two stages of amplification circuits are disconnected.
According to the control method of the radio frequency amplifier provided by the embodiment of the invention, the on-off of the second-stage amplifying circuit is controlled according to the circuit control signal applied to the second-stage amplifying circuit, and then the on-off of the bypass circuit is controlled according to the bypass control signal applied to the bypass circuit, so that one of the second-stage amplifying circuit and the bypass circuit is in conductive connection with the first-stage amplifying circuit, and the level of the circuit control signal is opposite to that of the bypass control signal. Thus, when the radio frequency amplifier is in a high gain mode, the bypass circuit is disconnected, the second-stage amplification circuit is connected with the first-stage amplification circuit in a conduction mode, so that the radio frequency signal is amplified after passing through the two-stage amplification circuit, and the circuit gain is the sum of the gains of the two-stage amplification circuit; when the radio frequency amplifier is in a low gain mode, the second-stage amplifying circuit is disconnected, the bypass circuit is in conductive connection with the first-stage amplifying circuit, so that radio frequency signals flow out of the bypass circuit after passing through the first-stage amplifying circuit to finish amplification, the circuit gain is only the gain of the first-stage amplifying circuit at the moment, the low noise amplifier has the characteristics of high linearity and low noise coefficient in bypass and non-bypass working modes, and the requirements of the linearity, the gain and the noise coefficient are met.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (10)
1. A radio frequency amplifier, comprising: the circuit comprises a first-stage amplifying circuit, a second-stage amplifying circuit and a bypass circuit; the radio frequency amplifier is also provided with a signal input end used for inputting radio frequency signals and a signal output end used for being connected with a load;
the first-stage amplifying circuit is connected with the second-stage amplifying circuit in series, the input end of the first-stage amplifying circuit is connected with the signal input end, and the output end of the second-stage amplifying circuit is connected with the signal output end and can be operated to control the on-off of the second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit;
the bypass circuit is connected to two ends of the second-stage amplification circuit in parallel and is operable to control the on/off of the bypass circuit according to a bypass control signal applied to the bypass circuit, so that one of the second-stage amplification circuit and the bypass circuit is conductively connected with the first-stage amplification circuit, and the circuit control signal is opposite to the bypass control signal in level.
2. The radio frequency amplifier of claim 1, wherein the second stage amplification circuit comprises a second stage amplifier and a first switch transistor, the circuit control signal comprises a first circuit control signal;
the input end of the second-stage amplifier is connected with the output end of the first-stage amplifying circuit, and the output end of the second-stage amplifier is connected with the output end of the second-stage amplifying circuit;
the first switch tube is connected to a power supply end of the second-stage amplifier and is operable to control the on-off of the first switch tube according to the first circuit control signal applied to the first switch tube, so that the on-off of the second-stage amplifier circuit is controlled.
3. The radio frequency amplifier of claim 2, wherein the second stage amplification circuit further comprises a second switching transistor, the circuit control signal comprising a second circuit control signal;
the second switch tube is connected to the ground terminal of the second-stage amplifier and is operable to control the on/off of the second switch tube according to the second circuit control signal applied thereto, so as to control the on/off of the second-stage amplifier circuit.
4. The radio frequency amplifier of claim 3, wherein the second stage amplification circuit further comprises a third switch transistor, the circuit control signal comprising a third circuit control signal;
the third switching tube is connected between the output end of the second-stage amplifier and the output end of the second-stage amplifying circuit and is operable to control the on-off of the third switching tube according to the third circuit control signal applied to the third switching tube, so that the on-off of the second-stage amplifying circuit is controlled.
5. The radio frequency amplifier of claim 4, wherein the first stage of amplification circuitry comprises a first stage amplifier and a first power-down control switch, and the second stage of amplification circuitry comprises a second power-down control switch;
the input end of the first-stage amplifier is connected with the signal input end, and the output end of the first-stage amplifier is connected with the output end of the first-stage amplifying circuit;
the first power-down control switch tube is connected to the grounding end of the first-stage amplifier, the second power-down control switch tube is connected between the second switch tube and the ground potential, and the first power-down control switch tube and the second power-down control switch tube can be operated to synchronously control the on-off of the first power-down control switch tube and the second power-down control switch tube according to power-down control signals loaded on the first power-down control switch tube and the second power-down control switch tube.
6. The RF amplifier of claim 1, wherein the bypass circuit is formed by a plurality of switch transistors connected in series in the same direction, and the gates of the switch transistors are controlled by the bypass control signal to control the on/off of the bypass circuit.
7. The radio frequency amplifier of claim 1, wherein the radio frequency amplifier comprises an input stage impedance matching circuit and an output stage impedance matching circuit;
the input stage impedance matching circuit comprises a first capacitor and a first inductor;
one end of the first capacitor is connected with the signal input end, and the other end of the first capacitor is connected with the first end of the first inductor; and the second end of the first inductor is connected with the input end of the first-stage amplifying circuit.
The output stage impedance matching circuit comprises a second capacitor, a third capacitor and a second inductor;
the second capacitor and the third capacitor are connected in series between the output end of the second-stage amplifying circuit and the signal output end; the second inductor is connected between the second capacitor and the third capacitor and to ground potential.
8. A method of controlling a radio frequency amplifier, adapted for use in a radio frequency amplifier as claimed in claims 1 to 7, the method comprising:
controlling the on-off of the second-stage amplifying circuit according to a circuit control signal applied to the second-stage amplifying circuit;
according to a bypass control signal applied to a bypass circuit, the on-off of the bypass circuit is controlled, so that one of the second-stage amplification circuit and the bypass circuit is in conductive connection with the first-stage amplification circuit, and the level of the circuit control signal is opposite to that of the bypass control signal.
9. The method for controlling a radio frequency amplifier according to claim 1, wherein when the radio frequency amplifier is in a high gain mode, the circuit control signal is at a high level, the bypass control signal is at a low level, so that the bypass circuit is turned off, and the second stage amplifier circuit is connected to the first stage amplifier circuit in a conductive manner, so that the input radio frequency signal is amplified after passing through the two stages of amplifier circuits;
when the radio frequency amplifier is in a low gain mode, the circuit control signal is at a low level, the bypass control signal is at a high level, so that the second-stage amplification circuit is disconnected, and the bypass circuit is in conductive connection with the first-stage amplification circuit, so that the input radio frequency signal flows out of the bypass circuit after passing through the first-stage amplification circuit to complete amplification.
10. The method of controlling a radio frequency amplifier as set forth in claim 1, the method further comprising:
when the radio frequency amplifier is in a turn-off mode, when the power failure control signals loaded on the first power failure control switch tube and the second power failure control switch tube are at a low level, the first power failure control switch tube and the second power failure control switch tube are disconnected, so that the two stages of amplification circuits are disconnected.
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| CN202110521318.4A CN113315477A (en) | 2021-05-13 | 2021-05-13 | Radio frequency amplifier and control method thereof |
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| CN202110521318.4A CN113315477A (en) | 2021-05-13 | 2021-05-13 | Radio frequency amplifier and control method thereof |
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| CN115567013A (en) * | 2022-10-20 | 2023-01-03 | 臻智微芯(广州)技术有限公司 | Low-noise amplifier circuit based on bypass mode |
| CN116436420A (en) * | 2023-06-15 | 2023-07-14 | 苏州悉芯射频微电子有限公司 | High-performance low-noise amplifier |
| WO2023160431A1 (en) * | 2022-02-22 | 2023-08-31 | 锐石创芯(深圳)科技股份有限公司 | Low-noise amplification circuit and radio-frequency front-end module |
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