A kind of low noise amplifier biasing circuit of wide power voltage power supply
Technical field
The invention belongs to the wireless communication electronics technical field, relate to the biasing circuit of amplifier, relate in particular to a kind of low noise amplifier biasing circuit of wide power voltage power supply, be applied to the biasing circuit of wireless communication receiver system radio-frequency front-end low noise amplifier.
Background technology
Now, comprise various types of wireless communication systems and the technology develop rapidly of mobile communication and WLAN (wireless local area network), radio frequency integrated circuit (RFIC) worldwide becomes the focus of university, research institute and the related industry of communicating by letter research and development.The development of these wireless communication systems has formed the RFIC market of a rapid growth.Why radio circuit is subject to concern and the research in worldwide, is to be the Main Bottleneck of whole wireless transceiver system design due to it.In the element of radio frequency transceiver, the technical property requirements of RFIC has consisted of the ultimate challenge of RFIC.And meanwhile, the market user is again very harsh to the performance requirement of wireless product, i.e. the requirements such as low cost, low-power consumption, small size, high-performance, and this is a huge challenge.
LNA is first module in the wireless receiver system normally, is also indispensable key modules.The major function of LNA is that the wireless signal from the sub-micro volt of antenna reception is amplified to a certain size, with convenient follow-up module, signal is processed, and self introduces the little noise and non-linear of trying one's best simultaneously.This just requires LNA to have the attribute of low-noise factor, high-gain and high linearity.Simultaneously, LNA is between reception antenna and frequency mixer in wireless receiver system signal path, and for preventing that local oscillation signal from leaking into the antenna front end from frequency mixer and causing interference, LNA also needs to have high-isolation.SiGe HBT LNA can satisfy the demand preferably: have extremely low noise factor concurrently, the higher linearity and the higher gain of CMOS LNA relatively.If adopt cascade (Cascode) structure, also can have high-isolation.
Angle from use, be in the initiating terminal of receiver due to LNA, its applied environment is relatively flexible, can integrate with reception antenna and be formed with source antenna, also can be used as the front that discrete chip is placed on the overall chip of receiver, can also be integrated in the overall chip internal of receiver, the power supply of diverse location may be different; Secondly, power supply managing planning is different, gives the supply power voltage possibility of LNA inconsistent; Again, in portable receiver is used, under the powered battery condition, be subjected to the impact of battery electric quantity, temperature etc., the supply power voltage of LNA also has variation by a relatively large margin.Therefore the design LNA that can work under wide power power voltage supply condition has important practical significance, and the key that realizes this LNA is to design and is subjected to supply voltage to affect little biasing circuit.
The actual biasing circuit that uses generally has three kinds of forms: the biasing of inductance feed-type, the biasing of resistance feed-type and duplex feeding biasing.
A) inductance feed-type biasing: it is good to have a noiseproof feature, the advantage that the linearity is high, but because it need to use outside a sheet or the sheet internal inductance, increased peripheral circuit complexity or chip area, in order to reduce cost, the designer more is ready to use resistance feed-type bias structure;
B) resistance feed-type biasing: need not the feed inductance that sheet is outer or sheet is outer, peripheral circuit or chip area have been saved, but this structure can be brought the deterioration of performance, be that noise factor and the linearity are difficult to take into account, the voltage drop of biasing circuit itself is higher in addition, is unfavorable at operation at low power supply voltage.
C) duplex feeding biasing: increase a feed path on the basis of resistance feed-type biasing, reach by the compensation to amplifier input HBT pipe base current the purpose that improves the linearity.This feeding classification has slightly been sacrificed noise factor and has been exchanged linearity raising to a certain degree for.But, because two feed leg all have higher voltage drop, therefore also be unfavorable at operation at low power supply voltage.
The low noise amplifier LNA of the resistance feed-type biasing of prior art as shown in Figure 1, is the biasing circuit of LNA in the dotted line frame.The biasing circuit annexation is: current source IB0 one termination power voltage VDD, the other end connect the collector electrode of biasing triode Q1 and the base stage of biasing triode Q2; The direct ground connection of emitter of biasing triode Q1, an end of its base stage and resistance R 1 joins, and the other end of resistance R 1 is connected with an end of resistance R 0 and the emitter of triode Q2; The collector electrode of triode Q2 and supply voltage VDD join; And the other end of resistance R 0 connect the LNA main amplifier input triode Q0 base stage and join with rf inputs RFIN.
The LNA of this traditional resistor feed-type biasing, the basic functional principle of its biasing circuit is: current source IB0 provides stable current offset for biasing triode Q1; Triode Q1 sets up base voltage with I-V characteristic rule, for the base stage of the input triode Q0 of LNA provides bias voltage; Biasing triode Q2 follows connection by emitter, forms the collector electrode of biasing triode Q1 to the negative feedback of base stage, with the dc offset voltage of stable biasing triode Q1 base stage.Resistance R 0 is used for
IsolationDirect current biasing and radio-frequency input signals, and resistance R 1 is current-limiting resistance, with the pressure drop on balance R0, main amplifying triode Q0 is equated with the base voltage of biasing triode Q1.
The biasing circuit of this resistance feed-type bias type in normal working conditions, requires supply voltage to add greater than the transistor base-emitter voltage of twice and the pressure drop of current source IB0 is greater than 1.8V under representative condition.There is the high defective of normal operation supply voltage in such biasing circuit, is unfavorable at operation at low power supply voltage especially.So this bias circuit construction is can not be applied in 1.8V or more in the amplifier circuit in low noise of low voltage power supply.
Summary of the invention
The objective of the invention is to propose a kind of low noise amplifier biasing circuit of wide power voltage power supply for overcoming the weak point of prior art existence.Under the prerequisite that does not worsen the indexs such as low noise amplifier noise, the linearity, gain, by improving resistance feed-type bias circuit construction, significantly improve the performance of LNA under the low supply voltage power supply of resistance feed-type biasing, thereby realized the wide power voltage power supply of this type of low noise amplifier.
Above-mentioned purpose of the present invention realizes by the following technical solutions:
A kind of low noise amplifier biasing circuit of wide power voltage power supply, the amplifier circuit in low noise formation comprises main circuit and biasing circuit; It is characterized in that, biasing circuit is the circuit structure of wide power voltage power supply, and its circuit formation comprises a main biasing circuit, a bias stabilization feedback circuit and a bias current source generating circuit; Wherein:
Described bias stabilization feedback circuit, it is made of the emitter follower of dual serial cascade, is used to main biasing circuit that stable feedback current is provided;
Described bias current source generating circuit, it is made of two the first parallel current sources and the second current source; One end of the first current source and the second current source also attaches to power vd D, and the other end of the first current source is corresponding connects main biasing circuit, and being used for provides not bias current with mains voltage variations to main bias current; The corresponding bias stabilization feedback circuit that connects of the other end of the second current source is used for providing not bias current with mains voltage variations to the bias stabilization feedback branch.
Annexation is: the offset side of main biasing circuit is connected with the bias stabilization feedback circuit, and the biasing feedback end of bias stabilization feedback circuit is received the biasing feedback input end of main biasing circuit; The bias current source generating circuit of double-current source structure, a current output terminal of the first current source and the second current source, a corresponding electric current injection end that connects main biasing circuit and bias stabilization feedback circuit; The biasing output VB of main biasing circuit connects the offset side of the main amplifying circuit of low noise amplifier, is used to main amplifying circuit to provide and has wide power voltage power supply scope and stable bias voltage V
B
Described low noise amplifier biasing circuit, it is that described main biasing circuit comprises biasing triode Q1, current-limiting resistance R0 and balance resistance R 1; Biasing triode Q1 collector electrode connects the current output terminal of the first current source IBO, the grounded emitter of Q1 pipe, the base stage of Q1 pipe connects the end of balance resistance R1, the end of the other end of balance resistance R1 and current-limiting resistance R0 also connects, and connect the end VB for the biasing feedback end, the other end of current-limiting resistance R0 is the output of main biasing circuit.
Described low noise amplifier biasing circuit, it is that described bias stabilization feedback circuit is comprised of triode Q2, Q4 and resistance R 3, two connected in series forming of emitter follower that triode Q2 and Q4 form respectively, one end of triode Q2 emitter connecting triode Q4 base stage and resistance R 3, the other end ground connection of resistance R 3; The collector electrode of triode Q4 is received the second current source output, and this link is connected to the offset side VB of main biasing circuit as the feedback end of bias stabilization feedback circuit.
Described low noise amplifier biasing circuit, it is that described bias current source generating circuit is comprised of the first current source IB0 and the 2nd IB1 current source; One termination power VDD of the first current source IB0 and the 2nd IB1 current source, the other end of the first current source IB0 are connected to the collector electrode of main biasing circuit biasing triode Q1, and the other end of the 2nd IB1 current source is received the ground level of bias stabilization feedback circuit triode Q2.
Described low noise amplifier biasing circuit, it is that two emitter follower triode Q2 of described bias stabilization feedback circuit serial connection and Q4 are complementary class cast; Triode Q2 is the NPN type, and triode Q4 is positive-negative-positive; Be used for the direct current pressure drop of bias stabilization feedback branch is close to zero.
Described low noise amplifier biasing circuit, its first current source IB0 that is described bias current source generating circuit is identical with the second current source IB1 circuit structure, is the current mirror type current source.
Described low noise amplifier biasing circuit, it is that the triode of described main biasing circuit, bias current source generating circuit and bias stabilization feedback circuit is BJT type pipe or MOS type pipe.
In sum, the low noise amplifier biasing circuit of disclosed a kind of wide power voltage power supply, on the basis of traditional resistor feed-type biasing circuit, to provide base bias current also by triode Q2 triode Q2, Q3 in Fig. 2 of feedback stability base bias voltage in Fig. 1, resistance R 3 and current source IB1 substitute.But be in fact the low noise amplifier biasing circuit that proposes a kind of wide power voltage power supply, comprise a main biasing circuit, a bias stabilization feedback branch and a bias current source generating circuit.Main biasing circuit, it is current mirror type resistance feed-type circuit structure; The bias stabilization feedback circuit, it is made of the emitter follower of dual serial cascade, is used to main biasing circuit that stable feedback current is provided; The bias current source generating circuit, it is made of two the first parallel current sources and the second current source; Two triodes of bias stabilization feedback circuit are two complementary class casts, make the direct current pressure drop of bias stabilization feedback branch close to zero.The bias circuit construction of wide power voltage power supply of the present invention, the new approaches of proposition circuit design have and widen normal operation supply voltage scope and improve the LNA linearity and the noise factor plurality of advantages.
The substantial effect of the present invention, the low noise amplifier biasing circuit of wide power voltage power supply compared with prior art has following substantial advantage:
1, the present invention introduces the bias stabilization feedback circuit in resistance feed-type biasing circuit, to stablize the negative feedback branch structure form of bias voltage, source follower is become the source follower without the direct current pressure drop that is become by two source follower cascaded series, increased substantially the tolerance performance of biasing circuit to low-voltage.
2, the bias current source generating circuit that consists of with first current source and second current source in biasing circuit of the present invention, the dc bias current of source follower no longer equals the base current sum of triode Q0 and Q1, make the source electrode input impedance of source follower controlled, be conducive to low noise amplifier and take into account noise factor and linearity performance.
3, biasing circuit of the present invention is under the prerequisite that realizes wide power voltage power supply target, take into account and improve low noise amplifier linearity performance, simultaneously, effectively improve the noise-figure performance of low noise amplifier, can be widely used at 1.8V or the amplifier circuit in low noise of low voltage power supply more.
Description of drawings
Fig. 1 is the resistance feed-type low noise amplifier biasing circuit schematic diagram of prior art;
In Fig. 1; 11-main amplifying circuit, 12-biasing circuit.
Fig. 2 a is the low noise amplifier biasing circuit schematic block diagram of the wide power voltage power supply of first embodiment of the invention;
Fig. 2 b is the low noise amplifier biasing circuit schematic diagram of the wide power voltage power supply of second embodiment of the invention;
In Fig. 2 a and Fig. 2 b; 21-main amplifying circuit, 22-main biasing circuit, 221-main biasing circuit, 222-bias stabilization feedback circuit, 223-bias current source generating circuit, RFin-radio-frequency (RF) signal input end, RFout-radiofrequency signal output, VBc-Cascode transistor biasing voltage.
Fig. 3 is in the low noise amplifier biasing circuit embodiment schematic diagram 3 of wide power voltage power supply of second embodiment of the invention; 31-main amplifying circuit, 32-main biasing circuit, 321-main biasing circuit, 322-bias stabilization feedback circuit, 323-bias current source generating circuit.
Fig. 4 a is the low noise amplifier minimum power supply voltage, simulation curve schematic diagram based on prior art biasing circuit shown in Figure 1;
Fig. 4 b is the low noise amplifier minimum power supply voltage, simulation curve schematic diagram based on Fig. 2 b biasing circuit of the present invention;
In Fig. 4 a and Fig. 4 b: GT dB10-power gain, NF dB10-noise factor.
Fig. 5 is the simulation comparison experiment schematic diagram based on the noise factor index of the low noise amplifier of the present invention and prior art biasing circuit shown in Figure 1.
Fig. 6 a is the simulation experiment result schematic diagram based on the input third order intermodulation point IIP3 of the low noise amplifier of prior art biasing circuit shown in Figure 1.
Fig. 6 b is the simulation experiment result schematic diagram based on the input third order intermodulation point IIP3 of the low noise amplifier of biasing circuit of the present invention.
Embodiment
The low noise amplifier biasing circuit of the wide power voltage power supply that the present invention is proposed below in conjunction with accompanying drawing and embodiment elaborates:
The first embodiment
Fig. 2 a illustrates the low noise amplifier biasing circuit schematic block diagram of the wide power voltage power supply of first embodiment of the invention.Low noise amplifier is comprised of main amplifying circuit 21 and biasing circuit 22.Biasing circuit 22 is biasing circuits of wide power voltage power supply, comprises main biasing circuit 221, bias stabilization feedback circuit 222 and bias current source generating circuit 223.The offset side of main biasing circuit 221 is connected with bias stabilization feedback circuit 222, and the bias stabilization feedback of bias stabilization feedback circuit 222 is received the biasing feedback input end of main biasing circuit 221.Bias current source generating circuit 223 consists of for the double-current source, and two current sources respectively have a current output terminal, the corresponding electric current injection end that connects main biasing circuit 221 and bias stabilization feedback circuit 222.The biasing output VB of main biasing circuit 221 connects the offset side of the main amplifying circuit 21 of low noise amplifier, is used to main amplifying circuit to provide and has wide power voltage power supply scope and stable bias voltage V
B
The second embodiment
Fig. 2 b provides the low noise amplifier biasing circuit schematic diagram of the wide power voltage power supply of second embodiment of the invention, and it is the pipe level circuit diagram of the further refinement of low noise amplifier of Fig. 2 a wide power voltage power supply.Circuit formation with Fig. 2 a is identical, and the low noise amplifier of the wide power voltage power supply of the second embodiment is comprised of main amplifying circuit 21 and biasing circuit 22.Biasing circuit 22 is biasing circuits of wide power voltage power supply, and it comprises main biasing circuit 221, bias stabilization feedback circuit 222 and bias current source generating circuit 223.Referring to Fig. 2 b, main biasing circuit 221 comprises biasing triode Q1, resistance R 1 and R0.Bias stabilization feedback circuit 222 comprises biasing triode Q2 and Q4, resistance R 3.Bias current source generating circuit 223 comprises the first current source IB0 and the second current source IB1.The termination power VDD of the first current source IB0 and the second current source IB1, the other end of the first current source IB0 connects the biasing triode Q1 collector electrode of main biasing circuit and the biasing triode Q2 base stage of bias stabilization feedback circuit 222; The other end of the second current source IB1 connects the feedback triode Q4 collector electrode of bias stabilization feedback circuit 222 and the tie point VB of main biasing circuit resistance R 1 one ends and resistance R 0 one ends, the other end of resistance R 1 is connected with the base stage of triode Q1, and the input triode Q0 base stage of the other end of resistance R 0 and LNA main amplifying circuit is also joined with radio-frequency (RF) signal input end RFin; The grounded emitter of biasing triode Q1; The collector electrode of triode Q2 and power vd D join.
The collector electrode of the input triode pipe Q0 of LNA main amplifying circuit is connected with the emitter of output triode Q3, the base stage of input triode pipe Q0 connects the radio-frequency (RF) signal input end RFin of LNA, the base stage of output triode Q3 connects ... VBC, the collector electrode utmost point of output triode Q3 connects the end of load Zload, and this link is the output RFout of LNA main amplifying circuit.
The operation principle of the low noise amplifier biasing circuit of the second embodiment wide power voltage power supply is as follows: the current source IB0 of bias current source generating circuit 223 provides stable electric current to inject for the biasing triode Q1 of main biasing circuit 221, and current source IB1 provides stable bias voltage by resistance R 1 for biasing triode Q1 simultaneously; Bias current source generating circuit 223 current source IB0 are that the emitter follower triode Q2 of bias stabilization feedback circuit 222 injects stable bias current; Current source IB1 injects stable electric current to emitter follower triode Q4 collector electrode; Two emitter follower triode Q2 and Q4 are for being connected in series, and two emitter follower cascades form triode Q1 collector electrode to the negative feedbacks of base stage, to stablize the base voltage of offset Q1.Triode Q2 is NPN type triode, and triode Q4 is the positive-negative-positive triode, and the emitter follower of two serial connections is realized complementary.The resistance R 0 of main biasing circuit 221 plays metering function, by balance resistance R1, balance main amplifier 21 amplifies triode Q0 base current and flows through resistance R 0 and the pressure drop of generation, amplifying triode Q0 equates with the base voltage of biasing triode Q1, make main biasing circuit and radio-frequency input signals amplifier tube Q0 dc power minimum, obtain best wide power voltage and low-power consumption effect.One end of resistance R 3 connects the emitter-base bandgap grading of emitter follower triode Q2, the other end ground connection of resistance R 3, and resistance R 3 is emitter-base bandgap grading loads of emitter follower triode Q2, is used to the base stage of emitter follower triode Q4 that stable configuration voltages is provided.Main biasing circuit 221 biasing triode Q1 set up base voltage according to I-V characteristic rule, for LNA amplifies the bias voltage V that input triode Q0 provides wide power voltage, low-power consumption
B
The 3rd embodiment
Fig. 3 provides the low noise amplifier biasing circuit schematic diagram of the wide power voltage power supply of the embodiment of the present invention; As shown in Figure 3, described main biasing circuit 321 is by triode Q1, and resistance R 0, R1 and R4 form.Wherein triode Q1 sets up base voltage with I-V characteristic rule, provides bias voltage for LNA amplifies the input triode; Current-limiting resistance R0 is used for to the current limliting of main biasing circuit output direct current and to the obstruct of radio-frequency input signals, and balance resistance R1 is used for the pressure drop on balance resistance R0, thereby amplifying triode Q0 is equated with the base voltage of the triode Q1 that setovers; Resistance R 4 one ends connect the second current source M1, and the tie point VB end of other end contact resistance R0 and R1 is used for increasing the input impedance of biasing circuit when high frequency, to reduce biasing circuit to the impact of LNA noise factor.Resistance R 4 also can increase the input impedance of biasing circuit and affect the linearity performance of LNA when low frequency, need to consider the value of resistance R 4 for the requirement compromise of noise factor and the linearity, and in the 3rd embodiment, as preferably, resistance R 4 values are 11K ohm.
Described bias stabilization feedback circuit 322 is comprised of triode Q2, Q4 and resistance R 3.Wherein triode Q2, Q4 are two source followers, and triode Q2 is NPN type triode, and triode Q4 is the positive-negative-positive triode, and two source follower cascades form triode Q1 collector electrode to the negative feedback of base stage, to stablize base voltage.Resistance R 3 is loads of source follower transistor Q2, thereby regulates by the gain that the size of regulating resistance R3 can be regulated source follower the feedback intensity that branch road is stablized in negative feedback.
Described bias current generating circuit 323 is comprised of metal-oxide-semiconductor M0, M1 and M2 and Iref, and wherein Iref is current reference source circuit, and the reference current of its generation and supply voltage, temperature are irrelevant, or are directly proportional to temperature.Reference current amplifies by metal-oxide-semiconductor M0-M1 current mirror, forms stable bias current, and main biasing circuit 221 biasing triode Q1 set up base voltage according to I-V characteristic rule, for LNA amplifies the bias voltage V that input triode Q0 provides wide power voltage, low-power consumption
B
In the Cascode type source negative feedback of the biasing circuit of the wide power voltage power supply that Fig. 2 a, Fig. 2 b are connected with Fig. 3 and LNA, main amplifying circuit 21 is connected with the application of being connected, and the low noise amplifier biasing circuit of the wide power voltage power supply that proposes of the present invention can obtain good effect just.And be widely used in 1.8V or the amplifier circuit in low noise of low voltage power supply more.
Prior art adopts in the LNA of traditional resistor feed-type biasing circuit, the calculating formula of the minimum value of supply voltage:
≈ 2 * 0.8+0.2=1.8V;
The low noise amplifier minimum power supply voltage, the simulation experiment result of prior art biasing circuit shown in Figure 1 is as shown in Fig. 4 a.Use cadence spectreRF emulation, based on the low noise amplifier of prior art resistance feeding type biasing, its minimum operating voltage is about 1.6V, and supply voltage just can obtain performance preferably when 1.8V is above.
And the minimum value calculating formula of the supply voltage of the low noise amplifier biasing circuit of wide power voltage power supply of the present invention:
≈ 0.8+0.2=1.0V.
And the supply voltage experimental result of the low noise amplifier biasing circuit of wide power voltage power supply of the present invention is as shown in Fig. 4 b.Low noise amplifier based on biasing circuit of the present invention, its minimum operating voltage is about 1.0V, be that 1.2V can obtain optimum performance when above at supply voltage, with respect to the former, decrease the minimum operating voltage of LNA of resistance feed-type biasing, effectively widen the supply voltage scope of LNA normal operation.
Above-mentioned analysis as can be known, but the minimum operating voltage of the LNA of the present invention's decrease resistance feed-type biasing is used the supply voltage scope of LNA of the present invention and is widened 1.0V.Can be widely used in requirement and widen the circuit of supply voltage working range.
Fig. 5 figure provides the simulation comparison experiment schematic diagram based on the noise factor index of the low noise amplifier of the present invention and prior art biasing circuit shown in Figure 1.Fig. 6 a provides the experimental result schematic diagram based on the emulation input third order intermodulation point IIP3 of the low noise amplifier of prior art biasing circuit shown in Figure 1, and Fig. 6 b provides the experimental result schematic diagram based on the emulation input third order intermodulation point IIP3 of the low noise amplifier of biasing circuit of the present invention.Emulation testing condition: frequency input signal 1575MHz, power-30dBm.Third order intermodulation point IIP3 and the important parameter that is the evaluation circuit linearity, under cadence spectreRF simulated environment, the low noise amplifier of the resistance feeding type biasing of prior art, its noise factor NF is about 1.10dB(as shown in Figure 5 when the central task frequency is 1.575GHz), input third order intermodulation point IIP3 is-5.71dBm(is as shown in Fig. 6 a); And based on the low noise amplifier of biasing circuit of the present invention, its noise factor NF is about 0.91dB(as shown in Figure 5 when the central task frequency is 1.575GHz), input third order intermodulation point IIP3 is-2.72dBm(is as shown in Fig. 6 b), with respect to the former, the low noise amplifier of biasing circuit of the present invention guaranteeing under the condition that the linearity increases, and noise-figure performance has the obvious improvement of 0.19dB.In sum, the low noise amplifier biasing circuit of wide power voltage power supply of the present invention under the prerequisite that realizes wide power voltage power supply target, is taken into account and is improved low noise amplifier linearity performance, simultaneously, effectively improve the noise-figure performance of low noise amplifier.
Protection scope of the present invention is not limited to embodiments described herein.As long as various variations claims limit and the spirit and scope of the present invention determined in, these variations are apparent, all utilize example that the present invention conceives all at the row of protection.