Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of voltage controlled oscillator, has larger output voltage amplitude, can reduce the phase noise of whole circuit, improves phase noise performance.
The embodiment of the present invention provides a kind of voltage controlled oscillator with low noise and large tuning range, comprising: resonant circuit, negative resistance circuit, current source circuit and feedback circuit;
Described resonant circuit, for generation of the oscillator signal of voltage controlled oscillator, described resonant circuit is inductance and capacitance type resonant circuit, electric capacity wherein adopts MOS capacitive reactance pipe;
Described negative resistance circuit, for generation of negative resistance, the just resistance producing to offset described resonant circuit;
Described current source circuit, for generation of the electric current of voltage controlled oscillator work;
Described feedback circuit, feeds back to described current source circuit for the oscillator signal that described resonant circuit is produced.
Preferably, described resonant circuit comprises: differential inductance, a MOS capacitive reactance pipe, the 2nd MOS capacitive reactance pipe, the 3rd electric capacity, the 4th electric capacity, the first resistance and the second resistance;
One end of described differential inductance connects first node, and the other end connects Section Point;
The grid of a described MOS capacitive reactance pipe connects the 3rd node, and drain electrode is connected the first control voltage with source shorted together;
The grid of described the 2nd MOS capacitive reactance pipe connects the 4th node, and drain electrode is connected described first with source shorted together and controls voltage;
One end of described the first resistance connects described the 3rd node, other end ground connection;
One end of described the second resistance connects described the 4th node, other end ground connection;
The two ends of described the 3rd electric capacity connect respectively described first node and described the 3rd node, and the two ends of described the 4th electric capacity connect respectively described Section Point and described the 4th node;
Described first node is the first-phase contact of described resonant circuit and negative resistance circuit, output the first resonance signal, and described Section Point is the second-phase contact of described resonant circuit and negative resistance circuit, output the second resonance signal.
Preferably, described negative resistance circuit comprises: the first bipolar transistor, the second bipolar transistor, the 3rd resistance, the 4th resistance, the 5th electric capacity, the 6th electric capacity and the 11 electric capacity;
The base stage of the first bipolar transistor connects the 5th node, and collector electrode connects first node, and described first node is the first-phase contact of described negative resistance circuit and resonant circuit;
The base stage of the second bipolar transistor connects the 6th node, and collector electrode connects Section Point, and described Section Point is the second-phase contact of described negative resistance circuit and resonant circuit;
The emitter of the emitter of described the first bipolar transistor and described the second bipolar transistor joins, and the node joining is as the input of described negative resistance circuit and the output phase contact of current source circuit;
One end of the 3rd resistance connects described the 5th node, and the other end connects second and controls voltage;
One end of the 4th resistance connects described the 6th node, and the other end connects described second and controls voltage;
One end of the 5th electric capacity connects described first node, and the other end connects described the 6th node;
One end of the 6th electric capacity connects described Section Point, and the other end connects described the 5th node;
The two ends of the 11 electric capacity connect respectively described second and control voltage and ground.
Preferably, described current source circuit comprises: the 3rd bipolar transistor, the 4th bipolar transistor, the 5th resistance, the 6th resistance, the 9th electric capacity and the tenth electric capacity;
The base stage of described the 3rd bipolar transistor connects the 9th electric capacity of ground connection, and described base stage is the input of the first feedback signal, the grounded emitter of the 3rd bipolar transistor;
The base stage of described the 4th bipolar transistor connects the tenth electric capacity of ground connection, and described base stage is the input of the second feedback signal, the grounded emitter of the 4th bipolar transistor;
The collector electrode of the collector electrode of described the 3rd bipolar transistor and described the 4th bipolar transistor joins, and the node joining is as the input of negative resistance circuit and the output phase contact of current source circuit;
One end of described the 5th resistance connects the base stage of described the 3rd bipolar transistor, and the other end connects the 3rd and controls voltage;
One end of described the 6th resistance connects the base stage of described the 4th bipolar transistor, and the other end connects the 3rd and controls voltage.
Preferably, described feedback circuit comprises: the 7th electric capacity and the 8th electric capacity;
One end of described the 7th electric capacity connects the first output of resonant circuit, the other end connects the first signal input of current source circuit, the first resonance signal by described the 7th capacitive feedback to current source circuit, the first output that the other end of described the 7th electric capacity is voltage controlled oscillator;
One end of described the 8th electric capacity connects the second output of resonant circuit, the other end connects the secondary signal input of current source circuit, the second resonance signal by described the 8th capacitive feedback to current source circuit, the second output that the other end of described the 8th electric capacity is voltage controlled oscillator.
Preferably, the capacitance of described the 3rd electric capacity and the 4th electric capacity is than at least large 10 times of the capacitance of a MOS capacitive reactance pipe and the 2nd MOS capacitive reactance pipe.
Preferably, a described MOS capacitive reactance pipe and the 2nd MOS capacitive reactance pipe work in accumulation area or depletion region.
Preferably, described the first bipolar transistor and the second bipolar transistor are in forward service area.
Preferably, described the 3rd bipolar transistor and the 4th bipolar transistor are in forward service area.
Preferably, the capacitance of the 7th electric capacity and the 8th electric capacity be a MOS capacitive reactance pipe and the 2nd MOS capacitive reactance pipe capacitance 1/10th.
Compared with prior art, the present invention has the following advantages:
Provided by the invention have in low noise and large tuning range voltage controlled oscillator, and current source circuit is for generation of the electric current of voltage controlled oscillator work; Resonant circuit is for generation of the oscillator signal of voltage controlled oscillator; Described resonant circuit is inductance and capacitance type resonant circuit, and electric capacity wherein adopts MOS capacitive reactance pipe, increases the tuning range of circuit; Negative resistance circuit is for generation of negative resistance, to offset the just resistance of described resonant circuit generation; Described feedback circuit feeds back to described current source circuit for the oscillator signal that described resonant circuit is produced, thereby for current source injects new electric current, improves the service efficiency of voltage controlled oscillator.Thereby the voltage controlled oscillator that makes the embodiment of the present invention has larger output voltage amplitude.The output voltage amplitude of voltage controlled oscillator is larger, and its phase noise performance is just better.
Embodiment
For above-mentioned purpose of the present invention, feature and advantage can be become apparent more, below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail.
Referring to Fig. 2, this figure is the schematic diagram with the voltage controlled oscillator embodiment mono-of low noise and large tuning range provided by the invention.
The voltage controlled oscillator that the present embodiment provides, comprising: resonant circuit 100, negative resistance circuit 200, current source circuit 300 and feedback circuit 400:
Described resonant circuit 100, for generation of the oscillator signal of voltage controlled oscillator, described resonant circuit 100 is inductance and capacitance type resonant circuit, electric capacity wherein adopts MOS capacitive reactance pipe;
Described negative resistance circuit 200, for generation of negative resistance, the just resistance producing to offset described resonant circuit 100;
Described current source circuit 300, for generation of the electric current of voltage controlled oscillator work;
Described feedback circuit 400, feeds back to described current source circuit 300 for the oscillator signal that described resonant circuit 100 is produced.
In voltage controlled oscillator provided by the invention, current source circuit 300 is for generation of the electric current of voltage controlled oscillator work; Resonant circuit 100 is for generation of the oscillator signal of voltage controlled oscillator; Described resonant circuit 100 is inductance and capacitance type resonant circuit, and electric capacity wherein adopts MOS capacitive reactance pipe, increases the tuning range of circuit; Negative resistance circuit 200 is for generation of negative resistance, to offset the just resistance of described resonant circuit 100 generations; Described feedback circuit 400 feeds back to described current source circuit 300 for the oscillator signal that described resonant circuit 100 is produced, thereby is that current source circuit 300 injects new electric current, improves the service efficiency of voltage controlled oscillator.Thereby the voltage controlled oscillator that makes the embodiment of the present invention has larger output voltage amplitude.The output voltage amplitude of voltage controlled oscillator is larger, and its phase noise performance is just better.
Below in conjunction with accompanying drawing, introduce the concrete structure of the voltage controlled oscillator that the embodiment of the present invention provides.
Referring to Fig. 3, this figure is the schematic diagram with the voltage controlled oscillator embodiment bis-of low noise and large tuning range provided by the invention.
The voltage controlled oscillator that the present embodiment provides, comprising: resonant circuit, negative resistance circuit, current source circuit and feedback circuit;
Described resonant circuit comprises: differential inductance L0, a MOS capacitive reactance pipe C1, the 2nd MOS capacitive reactance pipe C2, the 3rd capacitor C 3, the 4th capacitor C 4, the first resistance R 1, the second resistance R 2;
The tap of differential inductance L0 connects power supply.
One end of described differential inductance L0 connects first node A, and the other end connects Section Point B;
The grid of a described MOS capacitive reactance pipe connects the 3rd node C, and drain electrode is connected the first control voltage ATUNE with source shorted together;
The grid of described the 2nd MOS capacitive reactance pipe connects the 4th node D, and drain electrode is connected described first with source shorted together and controls voltage ATUNE;
This voltage controlled oscillator can be by regulating the size of the first control voltage ATUNE to regulate the operating frequency of voltage controlled oscillator.
One end of described the first resistance R 1 connects described the 3rd node C, other end ground connection;
One end of described the second resistance R 2 connects described the 4th node D, other end ground connection;
The two ends of described the 3rd capacitor C 3 connect respectively described first node A and the 3rd node C, and the two ends of described the 4th capacitor C 4 connect respectively described Section Point B and the 4th node D.
The first-phase contact that described first node A is described resonant circuit and negative resistance circuit, output the first resonance signal, the second-phase contact that described Section Point B is described resonant circuit and negative resistance circuit, output the second resonance signal.
It should be noted that, C1 and C2 work in accumulation area or depletion region.
The capacitance of described the 3rd capacitor C 3 and the 4th capacitor C 4, than at least large 10 times of the capacitance of a MOS capacitive reactance pipe C1 and the 2nd MOS capacitive reactance pipe C2, can guarantee that the voltage controlled oscillator that the embodiment of the present invention provides has wider frequency tuning range like this.
It should be noted that, the electric capacity in the resonant circuit of the embodiment of the present invention adopts MOS capacitive reactance pipe (C1 and C2).The capacitance size of MOS capacitive reactance pipe is larger with the variation of the first control voltage ATUNE, thereby adopts the voltage controlled oscillator of MOS capacitive reactance pipe to have larger tuning range.
Described negative resistance circuit comprises: the first transistor bipolar transistor Q1, the second bipolar transistor Q2, the 3rd resistance R 3, the 4th resistance R 4, the 5th capacitor C 5, the 6th capacitor C the 6, the 11 capacitor C 11;
The base stage of the first bipolar transistor Q1 connects the 5th node M, and collector electrode connects first node A, the first-phase contact that described first node A is described negative resistance circuit and resonant circuit;
The base stage of the second bipolar transistor Q2 connects the 6th node N, and collector electrode connects Section Point B, the second-phase contact that described Section Point B is described negative resistance circuit and resonant circuit;
The emitter of the emitter of described the first bipolar transistor Q1 and described the second bipolar transistor Q2 joins, and the node joining is as the input of described negative resistance circuit and the output phase contact of current source circuit;
One end of the 3rd resistance R 3 connects the 5th node M, and the other end connects second and controls voltage CDC;
One end of the 4th resistance R 4 connects the 6th node N, and the other end connects second and controls voltage CDC;
One end of the 5th capacitor C 5 connects described first node A, and the other end connects described the 6th node N;
One end of the 6th capacitor C 6 connects described Section Point B, and the other end connects described the 5th node M;
The effect of the 5th capacitor C 5 and the 6th capacitor C 6 is mainly for isolated DC signal, assists Q1 and Q2 to realize the effect of negative resistance simultaneously, thereby compensates the just resistance that resonant circuit produces.
The two ends of the 11 capacitor C 11 connect respectively described second and control voltage CDC and ground.
It should be noted that, can guarantee that Q1 and Q2 are in forward service area by adjusting the second size of controlling voltage CDC.
Described current source circuit comprises: the 3rd bipolar transistor Q3, the 4th bipolar transistor Q4, the 5th resistance R 5, the 6th resistance R 6, the 9th capacitor C 9 and the tenth capacitor C 10;
The base stage of described the 3rd bipolar transistor Q3 connects the 9th capacitor C 9 of ground connection, and described base stage is the input of the first feedback signal, the grounded emitter of the 3rd bipolar transistor Q3;
The base stage of described the 4th bipolar transistor Q4 connects the tenth capacitor C 10 of ground connection, and described base stage is the input of the second feedback signal, the grounded emitter of the 4th bipolar transistor Q4;
The collector electrode of the collector electrode of described the 3rd bipolar transistor Q3 and described the 4th bipolar transistor Q4 joins, and the node joining is as the input of negative resistance circuit and the output phase contact of current source circuit;
One end of described the 5th resistance R 5 connects the base stage of described the 3rd bipolar transistor Q3, and the other end connects the 3rd and controls voltage VBIAS;
One end of described the 6th resistance R 6 connects the base stage of described the 4th bipolar transistor Q4, and the other end connects the 3rd and controls voltage VBIAS.
It should be noted that, can make Q3 and Q4 in forward service area by controlling the voltage swing of VBIAS.
It should be noted that, C9 and C10 strobe, the high-frequency signal that filtering Q3 and Q4 produce.
It should be noted that, described Q1, Q2, Q3 and Q4 can be HBT.
Described feedback circuit comprises: the 7th capacitor C 7 and the 8th capacitor C 8;
One end of described the 7th capacitor C 7 connects first output (described first node A) of resonant circuit, the other end connects the first signal input of current source circuit, the first resonance signal feeds back to current source circuit by described the 7th capacitor C 7, the first output NOUT that the other end of described the 7th capacitor C 7 is voltage controlled oscillator;
One end of described the 8th capacitor C 8 connects second output (described Section Point B) of resonant circuit, the other end connects the secondary signal input of current source circuit, the second resonance signal feeds back to current source circuit by described the 8th capacitor C 8, the second output POUT that the other end of described the 8th capacitor C 8 is voltage controlled oscillator.
The effect of the 7th capacitor C 7 and the 8th capacitor C 8 is mainly every directly, AC signal is fed back to current source circuit simultaneously, for current source circuit injects new electric current.Thereby the oscillator signal that resonant circuit is produced has carried out feedback utilization, can improve service efficiency like this.
It should be noted that, POUT and NOUT are two outputs of voltage controlled oscillator, and the oscillator signal of these two output outputs is all signals of positive voltage, but the phase place of the oscillator signal of POUT and NOUT output is contrary.
The capacitance of the 7th capacitor C 7 and the 8th capacitor C 8 be a MOS capacitive reactance pipe C1 and the 2nd MOS capacitive reactance pipe C2 capacitance 1/10th, thereby guarantee that this voltage controlled oscillator has wider frequency tuning range.
Below in conjunction with Fig. 2, describe the operation principle of voltage controlled oscillator provided by the invention in detail.
The phase noise of voltage controlled oscillator can be expressed as:
Wherein F is empirical coefficient; K is Boltzmann constant; T is absolute temperature; Δ ω is with respect to carrier frequency ω
0deviation frequency; V
maxvoltage amplitude for resonant circuit; R
efffor effective resistance.It is pointed out that phase noise is less, the phase noise performance of voltage controlled oscillator is better.
Current source circuit is for generation of the electric current of voltage controlled oscillator work;
Resonant circuit and negative resistance circuit are for generation of oscillator signal;
The oscillator signal that resonant circuit and negative resistance resistance produce feeds back to HBT(Q3 and Q4 in current source circuit by the electric capacity in feedback circuit (C7 and C8)) base stage.Under identical direct current biasing condition, the current source circuit of the voltage controlled oscillator that the embodiment of the present invention provides has less pressure drop than the current source circuit of voltage controlled oscillator in prior art, thereby makes the voltage controlled oscillator of the embodiment of the present invention have larger output voltage amplitude.
From formula (1), the output voltage amplitude of voltage controlled oscillator is larger, and its phase noise performance is just better.
The pressure drop of the base-emitter of the output voltage of the voltage controlled oscillator that the embodiment of the present invention provides (the direct voltage of POUT and NOUT) Q3 or Q4, thus the peak-to-peak value voltage that voltage controlled oscillator is exported increased, improved the phase noise performance of voltage controlled oscillator.
Voltage controlled oscillator makes HBT(Q1 and Q4 by feedback circuit) base voltage there is similar phase place, and then make the electric current of voltage controlled oscillator reach minimum value in its noise sensitive area, thereby improved the phase noise performance of voltage controlled oscillator.
The above, be only preferred embodiment of the present invention, not the present invention done to any pro forma restriction.Although the present invention discloses as above with preferred embodiment, yet not in order to limit the present invention.Any those of ordinary skill in the art, do not departing from technical solution of the present invention scope situation, all can utilize method and the technology contents of above-mentioned announcement to make many possible changes and modification to technical solution of the present invention, or be revised as the equivalent embodiment of equivalent variations.Therefore, every content that does not depart from technical solution of the present invention,, all still belongs in the scope of technical solution of the present invention protection any simple modification made for any of the above embodiments, equivalent variations and modification according to technical spirit of the present invention.