Low-noise amplifier with adjustable input impedance, radio frequency front end, and electronic device

Abstract

Disclosed in the present invention are a low-noise amplifier with adjustable input impedance, a radio frequency front end, and an electronic device. The low noise amplifier comprises an adjustable load, a drive transistor, an inter-electrode switch unit, an amplifier unit, at least one first impedance adjustment unit and at least one second impedance adjustment unit, and an input coupling switch, a DC blocking capacitor and a source degeneration inductor. The inter-electrode switch unit is used for cooperating with the amplifier unit so as to enable selection and switching of gain levels; the amplifier unit is used for performing low-noise amplification on an input radio frequency signal; and the first impedance adjustment unit and the second impedance adjustment unit are used for adjusting the input impedance. When the low noise amplifier switches between a plurality of gain levels, the equivalent impedances of the first impedance adjustment unit and the second impedance adjustment unit are adjusted and controlled to be matched with the amplifier unit, such that the low noise amplifier can achieve consistency in input impedances at the plurality of gain levels.

Description

Input impedance adjustable low noise amplifier, radio frequency front end and electronic device TECHNICAL FIELD

[0001] The present application relates to an input impedance adjustable low noise amplifier, and also relates to a radio frequency front end comprising the low noise amplifier and a corresponding electronic device, and belongs to the technical field of radio frequency integrated circuits. BACKGROUND

[0002] A radio frequency front end generally comprises radio frequency power amplifiers, low noise amplifiers, radio frequency switches and filters and other components, wherein the low noise amplifier (LNA) as one of the important components in the radio frequency front end, its role is to amplify the received signal while minimizing noise introduction, plays an important role in the receiving performance, signal quality and area and cost of the entire radio frequency front end.

[0003] In the prior art, a typical architecture of a radio frequency front end is shown in Figure 1. Among them, the low noise amplifier usually needs to support multiple gain steps at the same time. In a communication system, it is usually required that the gain difference between each gain step in the same frequency band and between different frequencies in the receiving link remains the same or close. When the input impedance of the low noise amplifier is different between different gain steps, as shown in Figure 2, the gain difference of the receiving link between each gain step at different frequencies will change greatly, which will cause the communication quality or communication rate to decrease. Therefore, in the radio frequency front end of the communication system, it is necessary to make the input impedance of each gain step of the low noise amplifier as consistent as possible.

[0004] In the Chinese patent application with application number 202310296152.X, a gain adjustable low noise amplifier with optimized linearity is disclosed. The low noise amplifier comprises a linear bias adjustment module, an input matching adjustment module, an output matching adjustment module, a feedback adjustment module, an input transistor and an output transistor. Among them, the linear bias adjustment module is used to make the low noise amplifier in the bias state after optimizing the linearity based on the dynamically adjustable operating current, which includes a first current adjustment unit, a second current adjustment unit, an adaptive bias main circuit and a bias unit. The low noise amplifier can perform gain adjustment and impedance adjustment, thereby meeting the matching and noise requirements under different gains. SUMMARY

[0005] The primary technical problem to be solved by the present application is to provide an input impedance adjustable low noise amplifier.

[0006] Another technical problem to be solved by the present application is to provide a radio frequency front end comprising the low noise amplifier and a corresponding electronic device.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] According to a first aspect of the embodiments of the present application, there is provided an input impedance adjustable low noise amplifier. The low noise amplifier comprises an adjustable load, a driver tube, an inter-electrode switch unit, an amplifier unit, at least one first impedance adjusting unit and at least one second impedance adjusting unit, and an input coupling switch, a DC blocking capacitor and a source degeneration inductor; wherein,

[0009] The adjustable load is used to adjust the output impedance and the load frequency, and is composed of an adjustable resistance, an adjustable inductance and an adjustable capacitance;

[0010] The driver tube is used to drive and amplify the radio frequency signal;

[0011] The inter-electrode switch unit is used to cooperate with the amplifier unit to realize the selection and switching of the gain level, and is composed of a plurality of inter-electrode switches;

[0012] The amplifier unit is used to amplify the input radio frequency signal, and is composed of a plurality of amplifying transistors;

[0013] The first impedance adjusting unit is used to adjust the input impedance, and is composed of a capacitance circuit or a resistance-capacitance circuit;

[0014] The second impedance adjusting unit is used to adjust the input impedance, and is composed of a resistance circuit;

[0015] When the low noise amplifier switches between multiple gain levels, the equivalent impedance of the first impedance adjusting unit and the second impedance adjusting unit is adjusted and controlled, and cooperates with the amplifier unit to make the input impedance of the low noise amplifier consistent among multiple gain levels.

[0016] Preferably, the radio frequency signal input end is connected to one end of the input coupling switch, one end of the second impedance adjusting unit and one end of the DC blocking capacitor, respectively, and the other ends of the input coupling switch and the second impedance adjusting unit are connected to the ground potential end; the other end of the DC blocking capacitor is connected to the input end of the first impedance adjusting unit and the amplifier unit, the common end of the amplifier unit is connected to the ground potential end through the source degeneration inductor; the output end of the amplifier unit is connected to the input end of the inter-electrode switch unit, the output end of the inter-electrode switch unit is connected to the source end of the driver tube, the drain end of the driver tube is connected to one end of the adjustable load and the radio frequency signal output end, and the other end of the adjustable load is connected to the power supply end.

[0017] More preferably, the amplifier unit comprises a plurality of amplification transistors, wherein the gate terminals of each of the amplification transistors are connected to each other as an input terminal, connected to the radio frequency signal input terminal through the DC blocking capacitor, and connected to the first bias power supply terminal; the source terminals of each of the amplification transistors are connected to each other as a common terminal, connected to the ground potential through the source degeneration inductor; and the drain terminals of each of the amplification transistors are connected to the corresponding inter-electrode switch of the inter-electrode switch unit as an output terminal.

[0018] More preferably, the first impedance adjusting unit is composed of a capacitor circuit, which is composed of one or more capacitor branches connected in parallel to each other, wherein each of the capacitor branches is composed of a capacitor and a second control switch connected in series; the capacitor terminal of the capacitor circuit is connected to the input terminal of the amplifier unit, and the switch terminal of the capacitor circuit is connected to the common terminal of the amplifier unit.

[0019] More preferably, the second impedance adjusting unit is composed of the resistor circuit, which is composed of one or more resistors and a ground switch connected in series, wherein each of the resistors is connected in parallel to a first control switch; the resistor terminal of the resistor circuit is connected to the radio frequency signal input terminal, and the switch terminal of the resistor circuit is connected to the ground potential terminal.

[0020] More preferably, the low noise amplifier comprises a plurality of the first impedance adjusting units, each of which is composed of a capacitor circuit, and the capacitor terminal of each of the capacitor circuits is connected to the input terminal of the amplifier unit, and the switch terminal of each of the capacitor circuits is connected to the drain terminal of a different amplification transistor in the amplifier unit.

[0021] More preferably, the first impedance adjusting unit is composed of a resistor-capacitor circuit, which is composed of one or more resistor-capacitor branches connected in parallel to each other, wherein each of the resistor-capacitor branches is composed of a capacitor, a resistor, and a second control switch connected in series;

[0022] The capacitor terminal of the resistor-capacitor circuit is connected to the input terminal of the amplifier unit.

[0023] The switch terminal of the resistor-capacitor circuit is connected to the common terminal of the amplifier unit or the drain terminal of an amplification transistor in the amplifier unit.

[0024] More preferably, the amplifier unit comprises a first amplifier unit and a second amplifier unit, wherein the input terminal of the second amplifier unit is connected to the input terminal of the first amplifier unit through a switching switch.

[0025] The first amplifier unit is composed of multiple amplification transistors, the gate terminals of each of the amplification transistors are connected to each other as an input terminal, and the input terminal is connected to a radio frequency signal input terminal through a DC blocking capacitor, and is also connected to a first bias power supply terminal;

[0026] The second amplifier unit is composed of one amplification transistor, the gate terminal of the amplification transistor is connected to the input terminal of the first amplifier unit through the switch, and is also connected to a second bias power supply terminal.

[0027] Preferably, the input terminal of the first amplifier unit is connected to one of the second impedance adjustment units through a DC blocking capacitor; a first impedance adjustment unit is connected in parallel between the gate terminal and the drain terminal of each of the amplification transistors in the first amplifier unit; and the second impedance adjustment unit and the first impedance adjustment unit are used together to adjust the input impedance of each gain position in the first amplifier unit.

[0028] Preferably, the gate terminal of the amplification transistor in the second amplifier unit is connected to one of the second impedance adjustment units through a DC blocking capacitor, and the gate terminal and the source terminal are respectively connected to two terminals of one of the first impedance adjustment units; and the second impedance adjustment unit and the first impedance adjustment unit are used together to adjust the input impedance of the second amplifier unit.

[0029] Preferably, the two terminals of the DC blocking capacitor before the gate terminal of the amplification transistor in the second amplifier unit are respectively connected to two terminals of one of the first impedance adjustment units; and the equivalent capacitor formed by the DC blocking capacitor and the first impedance adjustment unit in parallel is used to adjust the input impedance of the second amplifier unit.

[0030] Preferably, in the low noise amplifier, the high gain position with high requirement for noise figure is realized by selecting the first amplifier unit by the inter-electrode switch unit; and the low gain position with high requirement for linearity is realized by selecting the second amplifier unit by the inter-electrode switch unit.

[0031] According to a second aspect of the embodiment of the present application, an input impedance adjustable low noise amplifier is provided.

[0032] According to a third aspect of the embodiment of the present application, an electronic device is provided, which comprises the input impedance adjustable low noise amplifier.

[0033] Compared with the prior art, the input impedance adjustable low noise amplifier provided by the application has the beneficial effects of ingenious and reasonable circuit design, flexible impedance adjustment and excellent circuit performance. BRIEF DESCRIPTION OF DRAWINGS

[0034] Fig. 1 is a schematic diagram of a typical radio frequency front-end architecture in the prior art;

[0035] Fig. 2 is a schematic diagram of the gain difference change between the gain positions of the receiving link of the low noise amplifier in the prior art;

[0036] Fig. 3 is a structural schematic diagram of an input impedance adjustable low noise amplifier provided by the application;

[0037] Fig. 4 is a circuit schematic diagram of the input impedance adjustable low noise amplifier in the first embodiment of the application;

[0038] Fig. 5 is an equivalent impedance conversion schematic diagram of the second impedance adjustment unit in the first embodiment of the application after the resistance and the input impedance are connected in parallel;

[0039] Fig. 6 is a circuit schematic diagram of the input impedance adjustable low noise amplifier in the second embodiment of the application;

[0040] Fig. 7 is a circuit schematic diagram of the low noise amplifier in which the first impedance adjustment unit adopts an RC circuit in the second embodiment of the application;

[0041] Fig. 8 is a circuit schematic diagram of the input impedance adjustable low noise amplifier in the third embodiment of the application;

[0042] Fig. 9 is a schematic diagram of an electronic device adopting the low noise amplifier provided by the application. DETAILED DESCRIPTION

[0043] The technical content of the application will be described in detail below in combination with the drawings and specific embodiments.

[0044] As shown in Fig. 3, the low-noise amplifier with adjustable input impedance provided by the embodiment of the present application comprises an adjustable load 101, a driving tube 102, an inter-electrode switch unit 103, an amplifier unit 104, at least one first impedance adjusting unit 105 and at least one second impedance adjusting unit 106, and an input coupling switch SW0, a direct-current blocking capacitor C0 and a source degeneration inductor L1. The radio frequency signal input terminal RF_IN is connected to one end of the input coupling switch SW0, one end of the second impedance adjusting unit 106 and one end of the direct-current blocking capacitor C0, respectively, and the other ends of the input coupling switch SW0 and the second impedance adjusting unit 106 are connected to the ground potential terminal; the other end of the direct-current blocking capacitor C0 is connected to the input terminal of the first impedance adjusting unit 105 and the amplifier unit 104, and the common terminal of the amplifier unit 104 is connected to the ground potential terminal through the source degeneration inductor L1; the output terminal of the amplifier unit 104 is connected to the input terminal of the inter-electrode switch unit 103, the output terminal of the inter-electrode switch unit 103 is connected to the source terminal of the driving tube 102, the drain terminal of the driving tube 102 is connected to one end of the adjustable load 101 and the radio frequency signal output terminal RF_OUT, and the other end of the adjustable load 101 is connected to the power supply VDD. DD

[0045] The adjustable load 101 is used for adjusting the output impedance and the load frequency; it can be composed of adjustable resistance, adjustable inductance and adjustable capacitance.

[0046] The driving tube 102 is used for driving and amplifying the radio frequency signal.

[0047] The inter-electrode switch unit 103 is used for cooperating with the amplifier unit 104 to realize the selection and switching of the gain gear; it is composed of multiple inter-electrode switches.

[0048] The amplifier unit 104 is used for low-noise amplifying the input radio frequency signal; it is composed of multiple amplifying transistors.

[0049] The first impedance adjusting unit 105 is used for adjusting the input impedance; it is composed of a capacitance circuit or a resistance-capacitance circuit.

[0050] The second impedance adjusting unit 106 is used for adjusting the input impedance; it is composed of a resistance circuit.

[0051] The input coupling switch SW0 is used for controlling the transmission path of the input radio frequency signal; it is composed of a shunt switch connected in parallel to the ground. When the shunt switch is open, the input radio frequency signal is transmitted to the amplifier unit 104 for amplification; when the shunt switch is closed, the input radio frequency signal is shunted to the ground.

[0052] ​When the low noise amplifier switches among multiple gain positions, the equivalent impedance of the first impedance adjusting unit and the second impedance adjusting unit is adjusted to make the input impedance of the low noise amplifier consistent with the multiple gain positions of the amplifier unit.

[0053] First embodiment

[0054] In the first embodiment of the present application, as shown in Fig. 4, an input impedance adjustable low noise amplifier includes an adjustable load 101, a driver tube 102, an inter-electrode switch unit 103, an amplifier unit 104, a first impedance adjusting unit 105, a second impedance adjusting unit 106, and an input coupling switch SW0, a DC blocking capacitor C0 and a source degeneration inductor L1.

[0055] The inter-electrode switch unit 103 includes a first inter-electrode switch K1, a second inter-electrode switch K2, …, and an mth inter-electrode switch Km (m is a positive integer). The second ends of the first inter-electrode switch K1, the second inter-electrode switch K2, …, and the mth inter-electrode switch Km are connected to each other as an output end and connected to the source end of the driver tube 102. The first ends of the first inter-electrode switch K1, the second inter-electrode switch K2, …, and the mth inter-electrode switch Km are connected to the corresponding amplifying transistors of the amplifier unit 104 as input ends.

[0056] The amplifier unit 104 includes a first amplifying transistor M1_1, a second amplifying transistor M1_2, …, and an mth amplifying transistor M1_m. The gate ends of the first amplifying transistor M1_1, the second amplifying transistor M1_2, …, and the mth amplifying transistor M1_m are connected to each other as an input end and connected to the radio frequency signal input end RF_IN through the DC blocking capacitor C0, and also connected to the first bias power supply end Vbis1. The source ends of the first amplifying transistor M1_1, the second amplifying transistor M1_2, …, and the mth amplifying transistor M1_m are connected to each other as a common end and connected to the ground potential through the source degeneration inductor L1. The drain ends of the first amplifying transistor M1_1, the second amplifying transistor M1_2, …, and the mth amplifying transistor M1_m are connected to the corresponding inter-electrode switches of the inter-electrode switch unit 103 as output ends. Generally, the gate ends of each amplifying transistor in the amplifier unit 104 have the same length.

[0057] The selection and switching of the multiple gain positions of the low noise amplifier is realized by controlling the closing or opening of each inter-electrode switch in the inter-electrode switch unit 103 to select the working state of the radio frequency path of each amplifying transistor in the amplifier unit 104. For example, when the first inter-electrode switch K1 is selected to be closed and other inter-electrode switches are opened, the first inter-electrode switch K1 connects the radio frequency path of the first amplifying transistor M1_1, and the input radio frequency signal is amplified by the first amplifying transistor M1_1 and then transmitted to the driver tube 102 through the first inter-electrode switch K1.

[0058] The first impedance adjusting unit 105 is composed of a capacitor circuit. The capacitor circuit is composed of one or more capacitor branches connected in parallel with each other, wherein each capacitor branch is composed of a capacitor (C1 / Cx) and a second control switch (SW2_1 / SW2_x) connected in series. The capacitor end of the capacitor circuit (i.e. the parallel circuit) is connected to the input end of the amplifier unit 104, and the switch end is connected to the common end of the amplifier unit 104. The first impedance adjusting unit 105 can also be composed of other capacitor circuits in series-parallel form, and the embodiments of the present application do not limit this.

[0059] The second impedance adjusting unit 106 is composed of a resistor circuit. The resistor circuit is composed of one or more resistors (R1 / Rn) and a ground switch (SW1_0) connected in series, wherein each resistor is connected in parallel with a first control switch (SW1_1 / SW1_n). The resistor end of the resistor circuit (i.e. the series circuit) is connected to the radio frequency signal input end RF_IN, and the switch end is connected to the ground potential end. The second impedance adjusting unit 106 can also be composed of other resistor circuits in series-parallel form, and the embodiments of the present application do not limit this.

[0060] In the present embodiment, the selection and switching of the multiple gain positions of the low noise amplifier is realized by controlling the closing or opening of each inter-electrode switch in the inter-electrode switch unit 103, so as to select the working state of the radio frequency path in which each amplification transistor in the amplifier unit 104 is located. For example, when the highest gain position is selected, all the inter-electrode switches in the inter-electrode switch unit 103 are closed, and the radio frequency paths in which all the amplification transistors in the amplifier unit 104 are located are in the working state. When the lowest gain position is selected, the first inter-electrode switch K1 in the inter-electrode switch unit 103 is closed, and the other inter-electrode switches are opened, the first inter-electrode switch K1 connects the radio frequency path in which the first amplification transistor M1_1 in the amplifier unit 104 is located, the first amplification transistor M1_1 is in the working state, and the other amplification transistors are in the non-working state. At this time, the drain ends of the second amplification transistor M1_2, …, the mth amplification transistor M1_m are all in the open state, and the gate end and the source end are connected together respectively as the gate end and the source end of the first amplification transistor M1_1, therefore, the parasitic capacitance Cgs (i.e. the total parasitic capacitance between the input end and the common end of the amplifier unit) between the gate end and the source end will affect the input impedance of the lowest gain position.

[0061] In FIG. 4, assuming that the first impedance adjusting unit 105 and the second impedance adjusting unit 106 are not connected, the calculation of the input impedance Zin is as follows:

[0062] wherein Cgs is the parasitic capacitance between the gate end and the source end of the amplification transistor; g mL1 is the total transconductance of the amplifying transistor in operation; L2 is the inductance of the source degenerate inductor; μ n For effective electron mobility; C ox V is the gate oxide capacitance; W and L are the total width and length of the gate terminal of the amplifying transistor in operation, respectively; gs V is the gate-source voltage; th This is the gate-source threshold voltage.

[0063] It can be seen from formulas (1) and (2) that, without the first impedance adjustment unit 105 and the second impedance adjustment unit 106 connected, the parasitic capacitance Cgs between the gate and source terminals is slightly smaller at the lowest gain level compared to the highest gain level, because the MOS transistor is in the linear region at the lowest gain level. Simultaneously, the total transconductance g... m Because the total width W decreases and becomes less than the total transconductance at the highest gain level, when the input impedance Zin is expressed as the formation of its real and imaginary parts, i.e., Zin = R + jX, both the real and imaginary parts of the input impedance at the lowest gain level are reduced. Therefore, to ensure that the input impedance of the low-noise amplifier remains consistent across all high and low gain levels, this invention adds a first impedance adjustment unit 105 and a second impedance adjustment unit 106 to adjust the input impedance at each gain level.

[0064] The first impedance adjustment unit 105 is composed of a capacitor circuit, with its two ends connected to the input terminal and common terminal of the amplifier unit 104, respectively. Therefore, after the equivalent capacitance of the capacitor circuit is connected in parallel with the parasitic capacitance Cgs between the gate and source terminals of the amplifying transistor, according to formula (1), the real part of the input impedance Zin decreases while the imaginary part increases. Furthermore, by controlling the closed or open state of the second control switch in each capacitor branch, the size of the equivalent capacitance of the capacitor circuit can be adjusted, thereby further adjusting the input impedance.

[0065] The second impedance adjustment unit 106 is composed of a resistor circuit, with its two ends connected to the RF signal input terminal RF_IN and the ground potential terminal, respectively. Therefore, the equivalent resistance R1 of the resistor circuit is equivalent to being connected in parallel with the input impedance Zin shown in formula (1). As shown in Figure 5, according to the equivalent transformation relationship of impedance series and parallel circuits, the parallel circuit of resistor R1 and impedance Zin can be equivalently transformed into a parallel circuit of resistor R1, resistor Rp and reactance jXp, and then the parallel circuit can be equivalently transformed into a series circuit of resistor Rs and reactance jXs, that is, the adjusted input impedance Zin, Zin = Rs + jXs. The calculation of resistance and reactance in the equivalent transformation process is explained below.

[0066] Calculate the equivalent resistance Rx of resistors R1 and Rp connected in parallel:

[0067] After the equivalent transformation, calculate the equivalent resistance Rs and the equivalent reactance jXs:

[0068] After the second impedance adjustment unit 106 is connected, the input impedance Zin = Rs + jXs. As can be seen from the equivalent transformation process shown in formulas (3), (4), and (5), the parallel resistor R1 provided by the second impedance adjustment unit 106 can increase the real and imaginary parts of the input impedance. Furthermore, by controlling the closing or opening state of the first control switch connected in parallel with each resistor, the magnitude of the equivalent resistance of the resistor circuit can be adjusted, and the magnitude of the input impedance can be further adjusted.

[0069] As can be seen from the above analysis, after the invention adds the first impedance adjustment unit 105 and the second impedance adjustment unit 106, when switching between multiple gain levels of the low-noise amplifier, by appropriately selecting the size of the equivalent capacitance and equivalent resistance, the real part and the imaginary part of the input impedance can be increased simultaneously, and the input impedance of the low gain level can be adjusted to be the same as that of the high gain level, thereby achieving the technical effect of adjustable input impedance.

[0070] Second Embodiment

[0071] In a second embodiment of the present invention, as shown in FIG6, a low-noise amplifier with adjustable input impedance includes an adjustable load 101, a driver transistor 102, an inter-electrode switching unit 103, an amplifier unit 104, a first impedance adjustment unit 105, a second impedance adjustment unit 106, an input coupling switch SW0, a DC blocking capacitor C0, and a source degradation inductor L1. The difference from the first embodiment lies in the connection method between the first impedance adjustment unit 105 and the amplifier unit 104, i.e., the circuit structure differs from the first embodiment.

[0072] In this embodiment, the low-noise amplifier may include multiple first impedance adjustment units 105. Each first impedance adjustment unit 105 is still composed of a capacitor circuit. The capacitor terminal of each capacitor circuit is connected to the input terminal of the amplifier unit 104, and the switching terminal of each capacitor circuit is connected to the drain terminal of different amplifying transistors in the amplifier unit 104. This connection method makes the equivalent capacitance of the capacitor circuit become the feedback capacitance of the amplifying transistor. The equivalent capacitances of the first impedance adjustment units 105 connected in parallel between the gate and drain of each amplifying transistor in the amplifier unit 104 may be the same or different, and can be adjusted according to circuit design requirements. Furthermore, the connection of the equivalent capacitance of the first impedance adjustment unit 105 can also reduce the real part of the input impedance and increase the imaginary part of the input impedance.

[0073] In this embodiment, by adding the first impedance adjustment unit 105 and the second impedance adjustment unit 106, when switching between multiple gain levels of the low-noise amplifier, the input impedance of the low-gain level and the input impedance of the high-gain level can be adjusted to be the same by appropriately selecting the equivalent capacitance and equivalent resistance, thereby achieving the effect of adjustable input impedance.

[0074] Furthermore, in this embodiment, the first impedance adjustment unit 105 can also be composed of a resistor-capacitor (RC) circuit, connected in parallel between the gate and drain of each amplifying transistor in the amplifier unit 104, forming an RC feedback circuit for the amplifying transistor. As shown in Figure 7, this resistor-capacitor circuit is composed of one or more resistor-capacitor branches connected in parallel, wherein each resistor-capacitor branch consists of at least one capacitor, one resistor, and a second control switch connected in series. The capacitor terminal of the resistor-capacitor circuit is connected to the input terminal of the amplifier unit 104, and the switch terminal is connected to the drain terminals of different amplifying transistors in the amplifier unit 104. According to the Miller effect, by selecting an appropriate RC value, the real and imaginary parts of the input impedance can be increased simultaneously in the first impedance adjustment unit 105 using an RC feedback circuit, making the input impedance at low gain levels and high gain levels the same, thereby achieving the technical effect of adjustable input impedance.

[0075] Third Embodiment

[0076] In a third embodiment of the present invention, as shown in FIG8, a low-noise amplifier with adjustable input impedance includes an adjustable load 101, a driver transistor 102, an inter-electrode switching unit 103, a first amplifier unit 104-1 and a second amplifier unit 104-2, as well as multiple first impedance adjustment units 105 and at least one second impedance adjustment unit 106, an input coupling switch SW0, a switching switch SW4, a source degradation inductor L1, and at least one DC blocking capacitor. The input terminal of the second amplifier unit 104-2 is connected to the input terminal of the first amplifier unit 104-1 via the switching switch SW4, forming a multi-stage amplification unit of the low-noise amplifier.

[0077] The first amplifier unit 104-1 is composed of multiple amplifying transistors. The gate terminals of each amplifying transistor are interconnected and connected to the radio frequency signal input terminal RF_IN through the DC blocking capacitor C0. At the same time, it is also connected to the first bias power supply terminal Vbis1. The source terminals of each amplifying transistor are interconnected and connected to the ground potential through the source degradation inductor L1. The drain terminals of each amplifying transistor are connected to the corresponding inter-electrode switches of the inter-electrode switching unit 103 as output terminals.

[0078] The input terminal of the first amplifier unit 104-1 is also connected to a second impedance adjustment unit 106 through a DC blocking capacitor C0. A first impedance adjustment unit 105 can be selectively connected in parallel between the gate and drain terminals of each amplifying transistor in the first amplifier unit 104-1. The second impedance adjustment unit 106 and the first impedance adjustment unit 105 are used together to adjust the input impedance of each gain level in the first amplifier unit 104-1.

[0079] The second amplifier unit 104-2 consists of an amplifying transistor. Its gate terminal is connected to the input terminal of the first amplifier unit 104-1 through a switching switch SW4, and is also connected to the second bias power supply terminal Vbis2. Its source terminal is connected to the common terminal of the first amplifier unit 104-1, and its drain terminal is connected to the corresponding inter-electrode switch of the inter-electrode switching unit 103.

[0080] In the second amplifier unit 104-2, the gate terminal of the amplifying transistor is connected to a second impedance adjustment unit 106 through a DC blocking capacitor C2. The gate terminal and the source terminal are respectively connected to the two ends of the first impedance adjustment unit 105. The second impedance adjustment unit 106 and the first impedance adjustment unit 105 are used together to adjust the input impedance of the second amplifier unit 104-2.

[0081] Typically, in low-noise amplifiers, the high-gain setting, which requires a higher noise figure, is achieved by the inter-electrode switching unit 103 selecting the first amplifier unit 104-1, while the low-gain setting, which requires higher linearity, can be achieved by the inter-electrode switching unit 103 selecting the second amplifier unit 104-2. In this embodiment, by placing the impedance adjustment unit required for the low-gain setting, i.e., the second amplifier unit 104-2, after the switching switch SW4, the impact of parasitic capacitance introduced by more impedance adjustment units on the gain setting corresponding to the high noise figure can be reduced.

[0082] Typically, the gate length of each amplifying transistor in the first amplifier unit 104-1 is the same, while the gate length of the amplifying transistor in the second amplifier unit 104-2 may be different from that in the first amplifier unit 104-1.

[0083] Furthermore, in this embodiment, a first impedance adjustment unit 105 can be selectively connected in parallel across the two ends of the DC blocking capacitor C2 before the input terminal of the second amplifier unit 104-2. The equivalent capacitance formed by the parallel connection of the DC blocking capacitor C2 and the first impedance adjustment unit 105 is connected in series before the input terminal of the second amplifier unit 104-2, which provides additional adjustment capability for the input impedance (imaginary part) of the second amplifier unit 104-2, so as to better achieve the technical effect of adjustable input impedance.

[0084] The circuit structure and working principle of a low-noise amplifier with adjustable input impedance provided by the present invention have been described in detail above through several specific embodiments. It should be noted that the above embodiments are merely examples, and the technical solutions of each embodiment can be combined, all of which are within the protection scope of the present invention.

[0085] Based on the aforementioned low-noise amplifier with adjustable input impedance, this embodiment of the invention further provides a radio frequency (RF) front-end, which includes at least one low-noise amplifier with adjustable input impedance. As an important component of the RF front-end, it is used to amplify the received RF signal with low noise, while simultaneously achieving consistent adjustable input impedance across multiple gain levels. The specific structure of the low-noise amplifier with adjustable input impedance in this RF front-end will not be described in detail here.

[0086] Furthermore, the low-noise amplifier with adjustable input impedance provided by this invention can be used in electronic devices as an important component of communication systems. The electronic devices referred to here are computer devices that can be used in mobile environments and support multiple communication standards such as GSM, EDGE, TD-SCDMA, TDD-LTE, and FDD-LTE, including mobile phones, laptops, tablets, and in-vehicle computers. In addition, the technical solution provided by this invention is also applicable to other applications of radio frequency integrated circuits, such as communication base stations and intelligent connected vehicles.

[0087] As shown in Figure 9, this electronic device includes at least a processor and a memory, and may further include communication components, sensor components, power supply components, multimedia components, and input / output interfaces as needed. The memory, communication components, sensor components, power supply components, multimedia components, and input / output interfaces are all connected to the processor. The memory can be static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, etc. The processor can be a central processing unit (CPU), graphics processing unit (GPU), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), digital signal processing (DSP) chip, etc. Other communication components, sensor components, power supply components, multimedia components, etc., can be implemented using general-purpose components, and will not be specifically described here.

[0088] In summary, compared with existing technologies, the low-noise amplifier with adjustable input impedance provided by this invention employs different connection methods between the impedance adjustment unit and the amplifier unit input terminal, and adjusts the equivalent impedance of the impedance adjustment unit via a control switch. This allows the low-noise amplifier to individually optimize the input impedance at different gain levels, achieving consistency in input impedance across multiple gain levels. This addresses the problem of significant gain differences at different frequency points in the receiving link. Therefore, the low-noise amplifier with adjustable input impedance provided by this invention offers advantages such as ingenious and reasonable circuit design, flexible impedance adjustment, and excellent circuit performance.

[0089] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0090] The above provides a detailed description of the low-noise amplifier with adjustable input impedance, its radio frequency front-end, and electronic equipment provided by this invention. Any obvious modifications made by those skilled in the art without departing from the essence of this invention will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

Claims

1. A low-noise amplifier with adjustable input impedance, characterized in that, It includes an adjustable load, a driver transistor, an inter-electrode switching unit, an amplifier unit, at least one first impedance adjustment unit and at least one second impedance adjustment unit, as well as an input coupling switch, a DC blocking capacitor, and a source degradation inductor; wherein, The adjustable load is used to adjust the output impedance and load frequency, and consists of an adjustable resistor, an adjustable inductor, and an adjustable capacitor. The driving transistor is used to drive and amplify the radio frequency signal; The inter-electrode switching unit is used in conjunction with the amplifier unit to realize the selection and switching of gain levels, and is composed of multiple inter-electrode switches; The amplifier unit is used to amplify the input radio frequency signal with low noise and is composed of multiple amplifying transistors. The first impedance adjustment unit is used to adjust the input impedance and is composed of a capacitor circuit or a resistor-capacitor circuit. The second impedance adjustment unit is used to adjust the input impedance and is composed of a resistor circuit; When the low-noise amplifier switches between multiple gain levels, the equivalent impedance of the first impedance adjustment unit and the second impedance adjustment unit is adjusted and controlled to cooperate with the amplifier unit so that the low-noise amplifier can achieve input impedance consistency across multiple gain levels.

2. The low-noise amplifier with adjustable input impedance as described in claim 1, characterized in that: The radio frequency signal input terminal is connected to one end of the input coupling switch, one end of the second impedance adjustment unit, and one end of the DC blocking capacitor, respectively. The other ends of the input coupling switch and the second impedance adjustment unit are connected to the ground potential terminal. The other end of the DC blocking capacitor is connected to the input terminals of the first impedance adjustment unit and the amplifier unit. The common terminal of the amplifier unit is connected to the ground potential terminal through the source degradation inductor. The output terminal of the amplifier unit is connected to the input terminal of the inter-electrode switching unit. The output terminal of the inter-electrode switching unit is connected to the source terminal of the driving transistor. The drain terminal of the driving transistor is connected to one end of the adjustable load and the radio frequency signal output terminal. The other end of the adjustable load is connected to the power supply terminal.

3. The low-noise amplifier with adjustable input impedance as described in claim 2, characterized in that: The amplifier unit includes multiple amplifying transistors. The gate terminals of each amplifying transistor are interconnected and connected to the radio frequency signal input terminal via the DC blocking capacitor. They are also connected to the first bias power supply terminal. The source terminals of each amplifying transistor are interconnected and connected to ground potential via the source degradation inductor. The drain terminals of each amplifying transistor are connected to the corresponding inter-electrode switches of the inter-electrode switching unit as output terminals.

4. The low-noise amplifier with adjustable input impedance as described in claim 2, characterized in that: The first impedance adjustment unit is composed of a capacitor circuit, which is composed of one or more capacitor branches connected in parallel. Each capacitor branch consists of a capacitor and a second control switch connected in series. The capacitor terminal of the capacitor circuit is connected to the input terminal of the amplifier unit, and the switch terminal of the capacitor circuit is connected to the common terminal of the amplifier unit.

5. The low-noise amplifier with adjustable input impedance as described in claim 2, characterized in that: The second impedance adjustment unit is composed of the resistor circuit, which is composed of one or more resistors and a grounding switch connected in series. Each resistor is connected in parallel with a first control switch. The resistor terminal of the resistor circuit is connected to the radio frequency signal input terminal, and the switch terminal of the resistor circuit is connected to the ground potential terminal.

6. The low-noise amplifier with adjustable input impedance as described in claim 2, characterized in that: The low-noise amplifier includes a plurality of first impedance adjustment units, each of which is composed of a capacitor circuit. The capacitor terminal of each capacitor circuit is connected to the input terminal of the amplifier unit, and the switching terminal of each capacitor circuit is connected to the drain terminal of a different amplifying transistor in the amplifier unit.

7. The low-noise amplifier with adjustable input impedance as described in claim 2, characterized in that: The first impedance adjustment unit is composed of a resistor-capacitor circuit, which is composed of one or more resistor-capacitor branches connected in parallel. Each resistor-capacitor branch is composed of a capacitor, a resistor and a second control switch connected in series. The capacitor terminal of the resistor-capacitor circuit is connected to the input terminal of the amplifier unit. The switching terminal of the resistor-capacitor circuit is connected to the common terminal of the amplifier unit or the drain terminal of one of the amplifying transistors in the amplifier unit.

8. The low-noise amplifier with adjustable input impedance as described in claim 2, characterized in that: The amplifier unit includes a first amplifier unit and a second amplifier unit, wherein the input terminal of the second amplifier unit is connected to the input terminal of the first amplifier unit via a switching switch; The first amplifier unit is composed of multiple amplifying transistors. The gate terminals of each amplifying transistor are interconnected and connected to the radio frequency signal input terminal through the DC blocking capacitor. At the same time, it is also connected to the first bias power supply terminal. The second amplifier unit consists of an amplifying transistor, whose gate terminal is connected to the input terminal of the first amplifier unit via the switching switch, and is also connected to the second bias power supply terminal.

9. The low-noise amplifier with adjustable input impedance as described in claim 8, characterized in that: The input terminal of the first amplifier unit is connected to a second impedance adjustment unit through the DC blocking capacitor; a first impedance adjustment unit is connected in parallel between the gate and drain terminals of each amplifying transistor in the first amplifier unit; the second impedance adjustment unit and the first impedance adjustment unit are used together to adjust the input impedance of each gain level in the first amplifier unit.

10. The low-noise amplifier with adjustable input impedance as described in claim 8, characterized in that: In the second amplifier unit, the gate terminal of the amplifying transistor is connected to a second impedance adjustment unit through the DC blocking capacitor, and the gate terminal and the source terminal are respectively connected to the two ends of a first impedance adjustment unit. The second impedance adjustment unit and the first impedance adjustment unit are used together to adjust the input impedance of the second amplifier unit.

11. The low-noise amplifier with adjustable input impedance as described in claim 10, characterized in that: In the second amplifier unit, the two ends of the DC blocking capacitor before the gate of the amplifying transistor are respectively connected to the two ends of the first impedance adjustment unit; the equivalent capacitance formed by the DC blocking capacitor and the first impedance adjustment unit in parallel is used to adjust the input impedance of the second amplifier unit.

12. The low-noise amplifier with adjustable input impedance as described in claim 8, characterized in that: In the low-noise amplifier, the high-gain setting, which requires a high noise figure, is achieved by the inter-electrode switching unit selecting the first amplifier unit; the low-gain setting, which requires a high linearity, is achieved by the inter-electrode switching unit selecting the second amplifier unit.

13. A radio frequency front end, characterized in that, The low-noise amplifier with adjustable input impedance as described in any one of claims 1 to 12.

14. An electronic device, characterized in that, The low-noise amplifier with adjustable input impedance as described in any one of claims 1 to 12.

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