CN102647157A

CN102647157A - Single-ended input differential output type radio frequency low-noise amplifier

Info

Publication number: CN102647157A
Application number: CN2012101031366A
Authority: CN
Inventors: 沈剑均; 杨阳; 叶松
Original assignee: JIANGSU TIANYUAN ELECTRONIC CO Ltd
Current assignee: JIANGSU TIANYUAN ELECTRONIC CO Ltd
Priority date: 2012-04-10
Filing date: 2012-04-10
Publication date: 2012-08-22

Abstract

The invention belongs to the technical field of a radio frequency integrated circuit and provides a single-ended input differential output type radio frequency low-noise amplifier. The single-ended input differential output type radio frequency low-noise amplifier comprises a single-ended input type main amplifying circuit I and an amplifier II for outputting inverse uniform-amplitude signals of the other path. An alternating-current signal addition feedback circuit is used for further adjusting balance of two paths of the output signals. The single-turn dual low-noise amplifier is compact in structure, is applicable to integration of a communication system of a receiver, and reduces equipment cost. The power consumption of the low-noise amplifier can be reduced, the volume is reduced, the gain is improved, the noise is optimized and the linearity is improved. Meanwhile, the single-ended input differential output type radio frequency low-noise amplifier has the advantages of being simple in structure, reducing off-chip elements, reducing extra system noise caused by off-chip Baelen and the like, and has a wide application prospect in a wireless communication receiving system.

Description

The radio frequency low-noise amplifier of single-ended input difference output

Technical field

The invention belongs to the wireless communication technical field, relate to the amplifier architecture design in RF IC (RFIC) technology, what designed is a kind of narrow-band low-noise amplifier circuit structure of single-ended transfer difference.

Background technology

In recent years; Fast development along with wireless communication technology; Enrich constantly in corresponding product market, like beep-pager, mobile phone, Beidou satellite navigation system (RDSS), global positioning system (GPS), radio frequency identification (RFID), short-distance wireless communication and transfer of data, DTV (DVB), wireless lan (wlan) or the like.These fields to performance of products, power consumption, volume and cost etc. require increasingly high; Promoted radio receiving transmitting module to stride forward towards miniaturization, low-power consumption, low-cost direction; Thereby brought very big challenge to product design; This challenge grows up and RF IC (RFIC) is just for tackling, and becomes the popular research field over past ten years.The radio transmission-receiving function that the RF IC technology realizes increasing former cause separation original paper is integrated in the middle of the one chip, and the system that makes advances towards the high integration direction, thereby reduces cost, power consumption, the volume of product.

Radio frequency low-noise amplifier is as one of key modules in the wireless receiver, and its noise factor has determined the noiseproof feature of whole system, is directly connected to the sensitivity of system.

In RF IC, generally all adopt differential amplifier, to suppress common-mode noise, improve systematic function.And often all be single-ended input from the signal that antenna is come in; Therefore need to realize the conversion of single-ended-to-difference; Traditional difference radio frequency low-noise amplifier needs extra single pair (Ba Lun) modules of changeing, and many designs all adopt passive balanced to unbalanced transformer to be connected before the radio frequency low-noise amplifier, realize the conversion of single-ended-to-difference; But this method can be introduced extra loss, worsens the system noise performance.

Summary of the invention

Technical problem to be solved by this invention is: to the shortcoming of above prior art existence; A kind of radio frequency low-noise amplifier of single-ended input difference output is proposed; The main communication system such as the Big Dipper that is suitable for, have low in energy consumption, noise is low, area is little, difference output balance quality is preferable.

The technical scheme that the present invention solves above technical problem is:

A kind of radio frequency low-noise amplifier of single-ended input difference output is characterized in that: comprise the second main amplifying circuit II of the first main amplifying circuit I of single-ended input, single-ended input and the negative-feedback circuit III of auxiliary adjustment balance; Said negative-feedback circuit III is the AC signal adder;

The said first main amplifying circuit I amplifies N transistor npn npn MN1 with common source to amplify N transistor npn npn MN2 with grid altogether is the amplifying circuit of core; The said second main amplifying circuit II amplifies N transistor npn npn MN3 with common source to amplify N transistor npn npn MN4 with grid altogether is the amplifying circuit of core; The grid of transistor MN1 and MN3 is connected the control voltage Vb1 and the Vb2 of external bias circuit respectively behind the radiofrequency signal blocking circuit; The grid of transistor MN2 and MN4 is connected the control voltage Vb3 and the Vb4 of external bias circuit respectively behind the radiofrequency signal blocking circuit;

Radio-frequency input signals RF _InThe signal input part of AC coupled to input port inductance L g, the signal output part of inductance L g connects the grid of transistor MN1; The drain electrode of transistor MN1 is connected with the source electrode of transistor MN2; The end of inductance L d1 is connected with the drain electrode of transistor MN2, and the other end of inductance L d1 connects power vd D;

The grid of transistor MN3 is connected with the drain electrode of transistor MN1 through grid source capacitor C 1; The source electrode of transistor MN3 is connected with the source electrode of transistor MN1 through inductance L s; The drain electrode of transistor MN3 is connected with the source electrode of transistor MN4; The end of inductance L d2 directly links to each other with the drain electrode of transistor MN4, and the other end of inductance L d2 connects power vd D;

The drain electrode of said transistor MN2 is as output port RF _Outp, the drain electrode of transistor MN4 is as output port RF _OutnTwo inputs of AC signal adder connect output port RF respectively _OutpWith output port RF _Outn, the output of AC signal adder connects the grid of transistor MN3, feeds back to the grid of MN3 to the difference of the two-way of the first main amplifying circuit I and second main amplifying circuit II output signal, is used to adjust the balance that two-way is exported signal;

The source electrode of said transistor MN3 is through isolating ground connection; The grid of said transistor MN2 is through isolating ground connection; Said transistor MN4 is through isolating ground connection.

The source electrode of said transistor MN3 and isolation method between the ground are to be connected ground connection inductance L gnd between source electrode and the ground of transistor MN3.

Said AC signal adder as negative-feedback circuit comprises: N transistor npn npn MN5, MN6, MN7, P transistor npn npn MP1 and MP2, capacitor C 7 and resistance R 5;

The grid of transistor MN5 connects output port RF respectively through coupling circuit _OutpAnd RF _OutnThe grid of transistor MN5 and MN6 is connected external bias circuit control voltage Vb5 respectively behind the radiofrequency signal blocking circuit; The grid of transistor MN7 connects external bias circuit control voltage Vb6 respectively behind the radiofrequency signal blocking circuit;

The source electrode of said transistor MN5 is connected with the source electrode of MN6, and their source electrode connects the drain electrode of transistor MN7; The source ground of transistor MN7;

The drain electrode of said transistor MP1 connects power vd D, and the source electrode of transistor MP1 is connected with the drain electrode of transistor MN5, and the source electrode of transistor MP1 is connected with grid;

The drain electrode of said transistor MP2 connects power vd D, and the source electrode of transistor MP2 is connected with the drain electrode of transistor MN6, and the grid of transistor MP1 is connected with the grid of transistor MP2;

The source electrode of said transistor MP2 is as the output port of negative-feedback circuit; This output port links to each other with the grid of transistor MN3 among the second main amplifier circuit II through coupling circuit on the one hand, feeds back to the grid of transistor MN5 on the other hand successively through resistance R 5 and capacitor C 7;

The coupling circuit that the grid of said transistor MN5 connects is an electric capacity.The coupling circuit that the output port of said negative-feedback circuit connects is an electric capacity.

The radiofrequency signal blocking circuit has been the high resistance measurement of blocking-up radiofrequency signal effect.

Inductance L d1 is identical with Ld2, and transistor MN1 and MN3 are measure-alike, and transistor MN2 and MN4 are measure-alike, and transistor MN5 and MN6 are measure-alike, and transistor MP1 and MP2 are measure-alike.

The first main amplifying circuit I, the second main amplifying circuit II and negative-feedback circuit III all are integrated in the chip piece radio-frequency input signals RF _InWith output signal RF _Outp, RF _OutnBeing to link to each other with external circuit through the metallic bond zygonema, is directly to be connected with negative-feedback circuit III at chip internal; Power vd D links to each other respectively with ground with the outer power supply of sheet through the metallic bond zygonema respectively with ground wire 6ND.

Advantage of the present invention is: (1) is eliminated preposition Ba Lun and is introduced additional noise with respect to traditional difference input and output radio frequency low-noise amplifier, thereby reduces system noise; (2) with respect to traditional single-ended output low noise amplifier, this circuit structure has the power gain about 15dB; (3) with respect to traditional single-ended output low noise amplifier, this circuit structure can be regulated the balance of output signal, has improved the output balance to a certain extent; (4) with respect to existing single-ended input difference output radio frequency low-noise amplifier; This amplifier is based on the design theory of narrow-band amplifier, and with respect to the active Ba Lun of traditional differential pair, this single-ended-to-difference amplifying circuit can reduce system noise; Reduce power consumption; Improve the linearity, compact conformation, thereby help improving the dynamic range of whole receiver.

Description of drawings

Fig. 1 is circuit topological structure figure of the present invention.

Fig. 2 is in the practical implementation, negative-feedback circuit figure.

Fig. 3 is a circuit diagram of the present invention.

Fig. 4 (a) is the balance frequency variation curve figure of differential output signal of the present invention.

Fig. 4 (b) is power gain of the present invention and input reflection coefficient curve chart.

Fig. 4 (c) is a noise factor curve chart of the present invention.

Embodiment

A kind of radio frequency low-noise amplifier of single-ended input difference output comprises the main amplifying circuit I of single-ended input, also comprises being used to realize that the second main amplifying circuit II and the balance of the reverse constant-amplitude signal output in another road regulate negative-feedback circuit.

The first main amplifying circuit I is the cascade low noise amplifier of an arrowband, is amplified N transistor npn npn MN1 and is total to grid amplification N transistor npn npn MN2 by common source and form, and realizes frequency-selecting through Lg and Ls impedance matching.Radiofrequency signal RF _InThrough the grid of matching network entering transistor MN1, the source electrode of transistor MN1 links to each other with the source electrode of the second main amplifying circuit II; The drain electrode of transistor MN1 adopts the sheet external inductance to connect power supply.

The second main amplifying circuit II is similarly a cascade low noise amplifier, is amplified N transistor npn npn MN3 and is total to grid amplification N transistor npn npn MN4 by common source and form.The input of this signal is provided by the first main amplifying circuit I; The input signal of the second main amplifying circuit II connects the grid that the first main amplifying circuit I gets into transistor MN1 through capacitor C 1, and the source electrode of transistor MN1 links to each other with the source electrode of the transistor MN3 of the second main amplifying circuit II; The drain electrode of transistor MN4 adopts the sheet external inductance to connect power supply.

The C3 of capacitor C 1 and transistor MN3 constitutes potential-divider network, can regulate the intensity of M2 input signal through the capacitance of regulating C1, and then can improve the amplitude of output voltage balance.Inductance L s is connecting the source electrode of transistor MN1 and transistor MN3; This inductance can be used for realizing the input port impedance matching of the first main amplifying circuit I on the one hand; Constituted the stability that a negative feedback network helps to improve circuit module on the other hand, this inductance has also been introduced a time delay network and can have been helped to improve two-way output signal RF simultaneously _OutpAnd RF _OutnPhase characteristic.Ground connection inductance L gnd is for adjustment two-way output signal RF in addition _OutpAnd RF _OutnBalance also played advantageous effect.Difference output RF _OutpAnd RF _OutnHave good balance, mainly comprise amplitude and phase characteristic.

In order further to improve the balance of output signal, the present technique scheme has also proposed a kind of new AC signal additive feedback circuit (like Fig. 2) of regulating negative-feedback circuit as balance.This balance is regulated the thinking of the design of negative-feedback circuit based on amplifier, and the difference that draws two-way output signal through computing feeds back to the balance that input is used to adjust two-way output signal.N transistor npn npn (MN5 and MN6) and P transistor npn npn (MP1 and MP2) and capacitor C 7 and resistance R 5 have constituted the circuit of feedback network.The grid of transistor MN5 is connected output port RF through capacitor C 5 respectively with C6 _OutpAnd RF _Outn, output port feeds back to the grid of MN5 through capacitor C 7 and resistance R 5.

The signal of present technique scheme moves towards explanation as follows:

Radiofrequency signal RF _InGet into the grid (this place is the mode that adopts capacitor C 0 coupling, also can adopt other coupled modes of the prior art) of transistor MN1 to the inductance L g through the electric capacity AC coupled; The source electrode of the source electrode of transistor MN1 and transistor MN3 is connected through inductance L s; The drain electrode of transistor MN1 is through the grid of capacitor C 1 input MN3; Differential signal RF _OutpAnd RF _OutnRespectively from the drain electrode load inductance Ld2 output of the common grid amplifier transistor MN4 of the drain electrode load inductance Ld1 of the common grid amplifier transistor MN2 of the first main amplifying circuit I and main amplifying circuit II;

AC signal addition feedback circuit is made up of with resistance R 5 N transistor npn npn MN5 and MN6 and P transistor npn npn MP1 and MP2 and capacitor C 7; The grid of transistor MN5 is connected output port RF through capacitor C 5 respectively with C6 _OutpAnd RF _Outn, output port feeds back to the grid of MN5 through capacitor C 7 and resistance R 5.

All unit of the present invention all are integrated in the chip piece, radio-frequency input signals RF _InWith link to each other output signal RF with external circuit through the metallic bond zygonema _Outp, RF _OutnDirectly link to each other with other circuit at chip internal; Power vd D links to each other respectively with ground with the outer power supply of sheet through the metallic bond zygonema with ground wire GND.

In present embodiment; The radio frequency low-noise amplifier of a kind of single-ended input, difference output comprises: the first main amplifying circuit I of single-ended input, be used to realize that the second main amplifier II and the balance of the reverse constant-amplitude signal output in another road regulate negative-feedback circuit.

The first main amplifier circuit I mainly is made up of N transistor npn npn MN1, N transistor npn npn MN2, inductance L d1, inductance L g and the inductance L s that is connected with N transistor npn npn MN3.Its annexation is: radiofrequency signal RF _InBe input to the grid of transistor MN1; The point that transistor MN1 is connected with transistor MN2 is through the input of electric capacity as main amplifier circuit II; Inductance L d1 meets power vd D; The grid of MN1 meets power supply Vb1 through R1; The grid of MN2 meets power supply Vb3 through R3; The capacitor C that grid connect 2 ground connection of MN2.

The second main amplifier circuit II is mainly by N transistor npn npn MN3, N transistor npn npn MN4, and inductance L d2, inductance L g and the inductance L s that is connected with N transistor npn npn MN3 and inductance L gnd form.

Its annexation is: the point that the transistor MN1 among the first main amplifier circuit I is connected with transistor MN2 is through the input of capacitor C 1 as the second main amplifier circuit II; Inductance L gnd ground connection GND; Inductance L d2 meets power vd D; The grid of MN3 meets power supply Vb2 through R2; The grid of MN4 meets power supply Vb4 through R4; The capacitor C that grid connect 3 ground connection of MN4.

When output network was in resonance point, output loading can equivalence be that a reality property impedance is analyzed.The C3 of capacitor C 1 and transistor MN3 constitutes potential-divider network, can regulate the intensity of M2 input signal through the capacitance of regulating C1, and then can improve the amplitude of output voltage balance.Inductance L s is connecting the source electrode of transistor MN1 and transistor MN3; This inductance can be used for realizing the input port impedance matching of the first main amplifying circuit I on the one hand; Constituted a negative feedback network on the other hand; Help to improve the stability of circuit module, this inductance L s has also introduced a time delay network simultaneously, can help to improve two-way output signal RF _OutpAnd RF _OutnPhase characteristic.

Negative-feedback circuit III is the AC signal adder circuit schematic diagram that provides in detail among Fig. 2, and this design philosophy is based on amplifier, and the difference that draws two-way output signal through computing feeds back to the balance that input is used to adjust two-way output signal.N transistor npn npn (MN5 and MN6) and P transistor npn npn (MP1 and MP2) and capacitor C 7 and resistance R 5 have constituted the circuit of negative feedback network.The grid of transistor MN5 is connected output port RF through capacitor C 5 respectively with C6 _OutpAnd RF _Outn, output port links to each other with the grid of MN3 pipe among the main amplifier circuit II through capacitor C 4 on the one hand, feeds back to the grid of MN5 on the other hand through capacitor C 7 and resistance R 5.

With 0.18um CMOS technology is example, and transistor is used metal-oxide-semiconductor entirely, and supply voltage is 1.8V, main body circuitry consumes electric current 4mA, and the circuit result of calculation of specific embodiment of the invention is shown in Fig. 4 (a), Fig. 4 (b), Fig. 4 (c).

Fig. 4 (a) is the balance frequency variation curve of differential output signal; As can be seen from the figure; In the 2.492GHz frequency range; The phase difference of active Ba Lun difference output is less than 1 °, and the output amplitude difference satisfies General System fully less than 0.1dB and requires (range error is less than 5%, and phase error is less than 5 °) for the differential signal balance.

Fig. 4 (b) is the power gain and the input reflection coefficient curve of radio frequency low-noise amplifier, from figure can know, the gain reach about 15dB, simultaneously, this Circuit Matching degree is good, 2.492GHz frequency range input reflection coefficient S11＜-28dB.

Can know that from Fig. 4 (c) in the 2.492GHz frequency range, the noise factor of whole low noise amplifier is less than 1.5dB, noise factor has reached 1.065dB, has good noiseproof feature.

Can know the radio frequency low-noise amplifier overall objective such as the following table 1 of the single-ended input that the present invention designed, difference output through the analysis of above practical implementation computational results:

Table 1

The present invention can also have other execution mode, and the technical scheme that equal replacement of all employings or equivalent transformation form all belongs within the scope of the present invention's protection.

Claims

1. the radio frequency low-noise amplifier of a single-ended input difference output is characterized in that: comprise the second main amplifying circuit II of the first main amplifying circuit I of single-ended input, single-ended input and the negative-feedback circuit III of auxiliary adjustment balance; Said negative-feedback circuit III is the AC signal adder;

2. the radio frequency low-noise amplifier of single-ended input difference output according to claim 1 is characterized in that the source electrode of said transistor MN3 and isolation method between the ground are to be connected ground connection inductance L gnd between source electrode and the ground of transistor MN3.

3. the radio frequency low-noise amplifier of single-ended input difference output according to claim 1; It is characterized in that said AC signal adder as negative-feedback circuit comprises: N transistor npn npn MN5, MN6, MN7; P transistor npn npn MP1 and MP2, capacitor C 7 and resistance R 5;

The source electrode of said transistor MP2 is as the output port of negative-feedback circuit; This output port links to each other with the grid of transistor MN3 among the second main amplifier circuit II through coupling circuit on the one hand, feeds back to the grid of transistor MN5 on the other hand successively through resistance R 5 and capacitor C 7.

4. the radio frequency low-noise amplifier of single-ended input difference output according to claim 3 is characterized in that the coupling circuit of the grid connection of said transistor MN5 is an electric capacity.

5. the radio frequency low-noise amplifier of single-ended input difference output according to claim 3 is characterized in that the coupling circuit of the output port connection of said negative-feedback circuit is an electric capacity.

6. according to the radio frequency low-noise amplifier of claim 1 or 3 described single-ended input difference outputs, it is characterized in that the radiofrequency signal blocking circuit has been the high resistance measurement of blocking-up radiofrequency signal effect.

7. the radio frequency low-noise amplifier of single-ended input difference output according to claim 3; It is characterized in that inductance L d1 and Ld2 are identical, transistor MN1 and MN3 are measure-alike, and transistor MN2 and MN4 are measure-alike; Transistor MN5 and MN6 are measure-alike, and transistor MP1 and MP2 are measure-alike.

8. according to the radio frequency low-noise amplifier of claim 1 or 3 or 7 described single-ended input difference outputs, it is characterized in that the first main amplifying circuit I, the second main amplifying circuit II and negative-feedback circuit III all are integrated in the chip piece radio-frequency input signals RF _InWith output signal RF _Outp, RF _OutnBeing to link to each other with external circuit through the metallic bond zygonema, is directly to be connected with negative-feedback circuit III at chip internal; Power vd D links to each other respectively with ground with the outer power supply of sheet through the metallic bond zygonema respectively with ground wire GND.