CN209105124U - A kind of voltage controlled oscillator - Google Patents
A kind of voltage controlled oscillator Download PDFInfo
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- CN209105124U CN209105124U CN201822153623.9U CN201822153623U CN209105124U CN 209105124 U CN209105124 U CN 209105124U CN 201822153623 U CN201822153623 U CN 201822153623U CN 209105124 U CN209105124 U CN 209105124U
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Abstract
The utility model discloses a kind of voltage controlled oscillators, are related to voltage controlled oscillator field；It includes control voltage module, current reference module and benchmark source module, the benchmark source module connects current reference module, the current reference module connection control voltage module, it further include the controlled oscillator of holohedral symmetry circuit structure, the control voltage module, current reference module and benchmark source module are separately connected controlled oscillator, the square wave that output frequency of oscillation is stable, duty ratio is 50%；Controlled oscillator in the voltage controlled oscillator of the utility model designs completely new constant current charge-discharge oscillator by cmos circuit, electric current and resistance in frequency of oscillation can cancel out each other temperature coefficient, avoiding existing frequency of oscillation from being inversely proportional to the big PN junction forward conduction voltage of temperature drift leads to the disadvantage of frequency of oscillation stability difference, reach the zero-temperature coefficient for realizing frequency of oscillation, improves the effect of the stability of frequency of oscillation.
Description
Technical field
The utility model relates to voltage controlled oscillator field, especially a kind of voltage controlled oscillator.
Background technique
Interchanger plays huge effect as composition indispensable in communication system；In communication process, due to making an uproar
The period of sound and interference, the data of transmission randomly changes, referred to as clock jitter, and clock jitter may cause the malfunction of circuit
Make, so as to cause system function failure；For reduce clock jitter need using phaselocked loop progress frequency stabilization with it is synchronous；Phaselocked loop includes
Voltage controlled oscillator, phase discriminator and loop filter, wherein oscillator refers to the frequency of output signal with input control voltage change
Oscillator；Oscillator includes tuning oscillator and multivibrator, wherein tuning oscillator generates the output close to sine wave；
Multivibrator generates the output of square wave or triangular wave；Control frequency of oscillation variation generally comprises three kinds of methods: one, changing vibration
Swing the passive elements parameters such as resistance, the inductance of device；Two, change oscillator active device parameters；Three, change oscillator timing element
Charging/discharging voltage or current value.With the development of modern communication, requirement of the electronic equipment to voltage controlled oscillator is higher and higher, passes
For the pressure controller of system because temperature drift is high, noise filtering not enough causes stability poor, especially emitter-base bandgap grading couples voltage controlled oscillator, vibrates model
It encloses greatly, by wilderness demand, but its frequency of oscillation is inversely proportional to the forward conduction voltage drop of diode, and voltage drop variation with temperature is about
It is -2mV/ degrees Celsius, causes frequency of oscillation that there is biggish positive temperature coefficient, therefore, it is difficult to meet electronics under modern communication environment
The requirement of equipment, it is therefore desirable to which a kind of voltage controlled oscillator can overcome temperature drift and noise, improve stability, meet modern communication ring
The requirement of electronic equipment under border.
Summary of the invention
The purpose of this utility model is that: the utility model provides a kind of voltage controlled oscillator, solves existing emitter-base bandgap grading coupling
The frequency of oscillation for closing voltage controlled oscillator is inversely proportional to the big PN junction forward conduction voltage of temperature drift, poor so as to cause frequency of oscillation stability
The problem of.
The technical solution adopted in the utility model is as follows:
A kind of voltage controlled oscillator, including control voltage module, current reference module and benchmark source module, a reference source mould
Block connects current reference module, and the current reference module connection control voltage module, further includes the stream of holohedral symmetry circuit structure
Oscillator is controlled, the control voltage module, current reference module and benchmark source module are separately connected controlled oscillator, output oscillation
Frequency stabilization, the square wave that duty ratio is 50%.
Preferably, the controlled oscillator includes the symmetrical differential amplifier circuit of two-stage, current mirror circuit, load electricity
Resistance, capacitor and current source, the differential amplifier circuit input terminal and output end are separately connected current mirror circuit, the current source
Between connect capacitor, described load resistance one end connects differential amplifier circuit input terminal, and the other end connects current mirror circuit.
Preferably, the differential amplifier circuit includes first order differential amplifier circuit and second level differential amplifier circuit, institute
Stating first order differential amplifier circuit includes metal-oxide-semiconductor N9-N12, and the second level differential amplifier circuit includes metal-oxide-semiconductor N5-N8；It is described
Metal-oxide-semiconductor N11 is connected with metal-oxide-semiconductor N12 in mirror symmetry, and the metal-oxide-semiconductor N9 is connected with metal-oxide-semiconductor N10 in mirror symmetry, the MOS
Pipe N11 grid connects input terminal IN1, and metal-oxide-semiconductor N12 grid connects input terminal IN2, the metal-oxide-semiconductor N9 and metal-oxide-semiconductor N10 grid, leakage
Pole is all connected with VDD, and the metal-oxide-semiconductor N9 source electrode is also connected with metal-oxide-semiconductor N8 grid, and the metal-oxide-semiconductor N10 source electrode is also connected with metal-oxide-semiconductor N7 grid
Pole；The metal-oxide-semiconductor N5 is connected with metal-oxide-semiconductor N6 in mirror symmetry, and the metal-oxide-semiconductor N7 is connected with metal-oxide-semiconductor N8 in mirror symmetry, described
Metal-oxide-semiconductor N7 drain electrode connects output end OUT1, output end OUT1 connection current mirror circuit one end, institute with metal-oxide-semiconductor N5 source electrode
It states metal-oxide-semiconductor N8 drain electrode and connects output end OUT2 with metal-oxide-semiconductor N8 source electrode, the output end OUT1 connection current mirror circuit is another
End, the metal-oxide-semiconductor N5 and metal-oxide-semiconductor N6 grid, drain electrode are all connected with VDD, realize holohedral symmetry differential amplification.
Preferably, the current mirror circuit include current mirror to P1P2, current mirror to P3P4, control switch group
Switch N3 grid, the N4 grid of N1N2 and switching group N3N4, the switching group N3N4 are separately connected output end OUT1, output end
OUT2, switch N3 source electrode, switch N4 source electrode are grounded after being all connected with current source I6, and switch N3 drain electrode is via load resistance R1 connection electricity
Traffic mirroring in P1P2 switch P1 drain, current mirror in P1P2 switch P1, P2 mirror symmetry connect, grid connect
Control switch group N1N2 is connected after connecing, source electrode connection after connect VDD, switch N4 drain electrode is via load resistance R2 connection electric current
Mirror image in P3P4 switch P4 drain, current mirror in P3P4 switch P3, P4 mirror symmetry connect, grid connection
Afterwards connect control switch group N1N2, source electrode connection after connect VDD；Load resistance is followed by via capacitor C connection current source I2
Ground is grounded after being also connected with current source I2；Load resistance is also connected with current source via being grounded after capacitor C connection current source I1
It is grounded after I2, is realized by the on-off of current mirror circuit and export differential amplifier circuit, realize charge and discharge electric oscillation.
Preferably, control switch group N1N2 includes metal-oxide-semiconductor N1 and metal-oxide-semiconductor N2, the metal-oxide-semiconductor N1 source electrode and the source metal-oxide-semiconductor N2
Pole is grounded after being all connected with current source I4, metal-oxide-semiconductor N1 drain electrode connection switch P2 drain electrode, metal-oxide-semiconductor N2 drain electrode connection switch P3 drain electrode,
Metal-oxide-semiconductor N1 grid connect metal-oxide-semiconductor N3 grid, metal-oxide-semiconductor N2 grid connect metal-oxide-semiconductor N4 grid, for control current mirror P1P2 and
P3P4 is to working condition.
In conclusion by adopting the above-described technical solution, the beneficial effects of the utility model are:
1. the controlled oscillator in the voltage controlled oscillator of the utility model designs completely new constant current charge and discharge by cmos circuit
Electrical oscillator, electric current and resistance in frequency of oscillation can cancel out each other temperature coefficient, and existing frequency of oscillation is avoided to be inversely proportional to temperature
Floating big PN junction forward conduction voltage leads to the disadvantage of frequency of oscillation stability difference, has reached the zero-temperature coefficient system for realizing frequency of oscillation
Number, improves the effect of the stability of frequency of oscillation；
2. the utility model uses cascade two-stage differential amplifying circuit, every grade of difference amplification circuit structure is identical, wide length
It inputs than very big NMOS tube to pipe, NMOS tube makees load resistance, increases every grade of gain amplifier, so that the input of difference is poor
Mould level is minimum, guarantees that the metal-oxide-semiconductor of amplifier is detached from saturation region and enters linear zone, guarantees directly to export logic level, using threshold
The complementary metal-oxide-semiconductor of value loss realizes on-off action, is designed using whole CMOS pipe, and strong interference immunity is low in energy consumption, guarantees to generate controllable
Periodic swinging frequency, conducive to stable frequency of oscillation is exported.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to needed in the embodiment attached
Figure is briefly described, it should be understood that the following drawings illustrates only certain embodiments of the present invention, therefore is not construed as pair
The restriction of range for those of ordinary skill in the art without creative efforts, can also be according to this
A little attached drawings obtain other relevant attached drawings.
Fig. 1 is the voltage controlled oscillator system block diagram of the utility model；
Fig. 2 is the circuit diagram of the controlled oscillator of the utility model；
Fig. 3 is the circuit diagram of the output voltage wave of the utility model；
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that described herein, specific examples are only used to explain the present invention, not
For limiting the present invention, i.e., described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is logical
The component for the embodiment of the present invention being often described and illustrated herein in the accompanying drawings can be arranged and be designed with a variety of different configurations.
Therefore, the detailed description of the embodiment of the present invention provided in the accompanying drawings is not intended to limit below claimed
The scope of the present invention, but be merely representative of selected embodiment of the invention.Based on the embodiment of the present invention, those skilled in the art
Member's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
It should be noted that the relational terms of term " first " and " second " or the like be used merely to an entity or
Operation is distinguished with another entity or operation, and without necessarily requiring or implying between these entities or operation, there are any
This actual relationship or sequence.Moreover, the terms "include", "comprise" or its any other variant be intended to it is non-exclusive
Property include so that include a series of elements process, method, article or equipment not only include those elements, but also
Further include other elements that are not explicitly listed, or further include for this process, method, article or equipment it is intrinsic
Element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that including described
There is also other identical elements in the process, method, article or equipment of element.
Technical problem: the frequency of oscillation for solving existing emitter-base bandgap grading coupling voltage controlled oscillator is inversely proportional to the big PN junction forward direction of temperature drift
Conducting voltage, so as to cause the problem of frequency of oscillation stability difference；
Technological means:
A kind of voltage controlled oscillator, including control voltage module, current reference module and benchmark source module, benchmark source module connect
Current reference module is connect, current reference module connection control voltage module, further includes the controlled oscillator of holohedral symmetry circuit structure,
Control voltage module, current reference module and benchmark source module are separately connected controlled oscillator, output frequency of oscillation stabilization, duty
Than the square wave for 50%.
Controlled oscillator includes the symmetrical differential amplifier circuit of two-stage, current mirror circuit, load resistance, capacitor and electric current
Source, differential amplifier circuit input terminal and output end are separately connected current mirror circuit, and capacitor, load resistance are connected between current source
One end connects differential amplifier circuit input terminal, and the other end connects current mirror circuit.
Differential amplifier circuit includes first order differential amplifier circuit and second level differential amplifier circuit, first order differential amplification
Circuit includes metal-oxide-semiconductor N9-N12, and second level differential amplifier circuit includes metal-oxide-semiconductor N5-N8；Metal-oxide-semiconductor N11 and metal-oxide-semiconductor N12 is in mirror image
Symmetrical connection, metal-oxide-semiconductor N9 and metal-oxide-semiconductor N10 are connected in mirror symmetry, and metal-oxide-semiconductor N11 grid connects input terminal IN1, metal-oxide-semiconductor N12 grid
Pole connection input terminal IN2, metal-oxide-semiconductor N9 and metal-oxide-semiconductor N10 grid, drain electrode are all connected with VDD, and metal-oxide-semiconductor N9 source electrode is also connected with metal-oxide-semiconductor N8
Grid, metal-oxide-semiconductor N10 source electrode are also connected with metal-oxide-semiconductor N7 grid；Metal-oxide-semiconductor N5 and metal-oxide-semiconductor N6 connects in mirror symmetry, metal-oxide-semiconductor N7 with
Metal-oxide-semiconductor N8 is connected in mirror symmetry, and metal-oxide-semiconductor N7 drain electrode connects output end OUT1, output end OUT1 connection electricity with metal-oxide-semiconductor N5 source electrode
Traffic mirroring circuit on one side, metal-oxide-semiconductor N8 drain electrode connect output end OUT2, output end OUT1 connection current mirror with metal-oxide-semiconductor N8 source electrode
The circuit other end, metal-oxide-semiconductor N5 and metal-oxide-semiconductor N6 grid, drain electrode are all connected with VDD, realize holohedral symmetry differential amplification.
Current mirror circuit include current mirror to P1P2, current mirror to P3P4, control switch group N1N2 and switching group
Switch N3 grid, the N4 grid of N3N4, switching group N3N4 are separately connected output end OUT1, output end OUT2, and switch N3 source electrode is opened
It closes after N4 source electrode is all connected with current source I6 and is grounded, switch N3 drain electrode is via load resistance R1 connection current mirror to opening in P1P2
Close P1 drain electrode, current mirror in P1P2 switch P1, P2 mirror symmetry connect, grid connection after connect control switch group
N1N2, source electrode connection after connect VDD, switch N4 drains via load resistance R2 connection current mirror to the switch in P3P4
P4 drain electrode, current mirror in P3P4 switch P3, P4 mirror symmetry connect, grid connection after connect control switch group
N1N2, source electrode connection after connect VDD；Load resistance is also connected with current source via being grounded after capacitor C connection current source I2
It is grounded after I2；Load resistance is grounded after being also connected with current source I2 via being grounded after capacitor C connection current source I1, passes through electric current
The on-off realization of mirror image circuit exports differential amplifier circuit, realizes charge and discharge electric oscillation.
Control switch group N1N2 includes metal-oxide-semiconductor N1 and metal-oxide-semiconductor N2, and metal-oxide-semiconductor N1 source electrode and metal-oxide-semiconductor N2 source electrode are all connected with electric current
It is grounded after the I4 of source, metal-oxide-semiconductor N1 drain electrode connection switch P2 drain electrode, metal-oxide-semiconductor N2 drain electrode connection switch P3 drain electrode, metal-oxide-semiconductor N1 grid connects
Metal-oxide-semiconductor N3 grid is connect, metal-oxide-semiconductor N2 grid connects metal-oxide-semiconductor N4 grid, for controlling current mirror P1P2 and P3P4 to work shape
State.
Technical effect: the controlled oscillator in the voltage controlled oscillator of the utility model designs completely new perseverance by cmos circuit
Charge and discharge electrical oscillator is flowed, the electric current and resistance in frequency of oscillation can cancel out each other temperature coefficient, avoid existing frequency of oscillation anti-
Than having reached and having realized the zero of frequency of oscillation in the disadvantage that it is poor that the big PN junction forward conduction voltage of temperature drift leads to frequency of oscillation stability
Temperature coefficient improves the effect of the stability of frequency of oscillation；Using cascade two-stage differential amplifying circuit, every grade of differential amplification electricity
Line structure is identical, and the very big NMOS tube of breadth length ratio is inputted to pipe, and NMOS tube makees load resistance, increases every grade of gain amplifier,
So that the input differential mode level of difference is minimum, guarantees that the metal-oxide-semiconductor of amplifier is detached from saturation region and enters linear zone, guarantee directly to export
Logic level is realized on-off action using the complementary metal-oxide-semiconductor of threshold value loss, is designed using whole CMOS pipe, strong interference immunity, power consumption
It is low, guarantee to generate controllable periodic swinging frequency, conducive to stable frequency of oscillation is exported.
Feature and performance of the invention are described in further detail with reference to embodiments.
Embodiment 1
Voltage controlled oscillator principle: voltage controlled oscillator includes control voltage module, current reference module, benchmark source module and stream
Oscillator is controlled, as shown in Figure 1；Benchmark source module generates reference voltage source and current source, reference voltage source are supplied to current reference
Module, current source are supplied to controlled oscillator, and current reference module provides partially after converting reference voltage source into controlled oscillator
It sets electric current, provide electric current for control voltage module；Voltage module is controlled by the frequency control voltage of input and scope control voltage
Electric current is converted to, and using its electric current as the frequency of oscillation of master control current control controlled oscillator；Controlled oscillator output frequency
The square wave that stable duty ratio is 50%.Entire circuit carries out constant current charge-discharge by each composition control voltage, realizes oscillation.
Controlled oscillator includes the symmetrical differential amplifier circuit of two-stage, current mirror circuit, load resistance, capacitor and electric current
Source, differential amplifier circuit input terminal and output end are separately connected current mirror circuit, and capacitor, load resistance are connected between current source
One end connects differential amplifier circuit input terminal, and the other end connects current mirror circuit.
As shown in Fig. 2, differential amplifier circuit includes first order differential amplifier circuit and second level differential amplifier circuit, first
Grade differential amplifier circuit includes metal-oxide-semiconductor N9-N12, and second level differential amplifier circuit includes metal-oxide-semiconductor N5-N8；Metal-oxide-semiconductor N11 and MOS
Pipe N12 is connected in mirror symmetry, and metal-oxide-semiconductor N9 is connected with metal-oxide-semiconductor N10 in mirror symmetry, and metal-oxide-semiconductor N11 grid connects input terminal
IN1, metal-oxide-semiconductor N12 grid connection input terminal IN2, metal-oxide-semiconductor N9 and metal-oxide-semiconductor N10 grid, drain electrode are all connected with VDD, metal-oxide-semiconductor N9 source electrode
It is also connected with metal-oxide-semiconductor N8 grid, metal-oxide-semiconductor N10 source electrode is also connected with metal-oxide-semiconductor N7 grid；Metal-oxide-semiconductor N5 and metal-oxide-semiconductor N6 connects in mirror symmetry
It connects, metal-oxide-semiconductor N7 is connected with metal-oxide-semiconductor N8 in mirror symmetry, and metal-oxide-semiconductor N7 drain electrode connects output end OUT1 with metal-oxide-semiconductor N5 source electrode, is exported
OUT1 connection current mirror circuit one end is held, metal-oxide-semiconductor N8 drain electrode connects output end OUT2, output end OUT1 with metal-oxide-semiconductor N8 source electrode
The current mirror circuit other end is connected, metal-oxide-semiconductor N5 and metal-oxide-semiconductor N6 grid, drain electrode are all connected with VDD, realize holohedral symmetry differential amplification.
Current mirror circuit include current mirror to P1P2, current mirror to P3P4, control switch group N1N2 and switching group
Switch N3 grid, the N4 grid of N3N4, switching group N3N4 are separately connected output end OUT1, output end OUT2, and switch N3 source electrode is opened
It closes after N4 source electrode is all connected with current source I6 and is grounded, switch N3 drain electrode is via load resistance R1 connection current mirror to opening in P1P2
Close P1 drain electrode, current mirror in P1P2 switch P1, P2 mirror symmetry connect, grid connection after connect control switch group
N1N2, source electrode connection after connect VDD, switch N4 drains via load resistance R2 connection current mirror to the switch in P3P4
P4 drain electrode, current mirror in P3P4 switch P3, P4 mirror symmetry connect, grid connection after connect control switch group
N1N2, source electrode connection after connect VDD；Load resistance is also connected with current source via being grounded after capacitor C connection current source I2
It is grounded after I2；Load resistance is grounded after being also connected with current source I2 via being grounded after capacitor C connection current source I1, passes through electric current
The on-off realization of mirror image circuit exports differential amplifier circuit, realizes charge and discharge electric oscillation.
Control switch group N1N2 includes metal-oxide-semiconductor N1 and metal-oxide-semiconductor N2, and metal-oxide-semiconductor N1 source electrode and metal-oxide-semiconductor N2 source electrode are all connected with electric current
It is grounded after the I4 of source, metal-oxide-semiconductor N1 drain electrode connection switch P2 drain electrode, metal-oxide-semiconductor N2 drain electrode connection switch P3 drain electrode, metal-oxide-semiconductor N1 grid connects
Metal-oxide-semiconductor N3 grid is connect, metal-oxide-semiconductor N2 grid connects metal-oxide-semiconductor N4 grid, for controlling current mirror P1P2 and P3P4 to work shape
State.
Using metal-oxide-semiconductor N3, metal-oxide-semiconductor N4, switch P1, switch P4 as the control switch of entire voltage controlled oscillator in circuit；By
NMOS tube is ended when gate control voltage is low level, and when gate control voltage is high level, PMOS tube is ended, in metal-oxide-semiconductor cut-off,
Pipe both ends separate, and play the role of switch OFF；But it, will be there is for single metal-oxide-semiconductor when its analog switch is connected
Threshold value loses problem；The transmission low level that it can be lossless for NMOS tube, and have threshold value loss when transmitting high level, due to
PMOS tube and NMOS tube have complementary performance PMOS tube it can be lossless transmission high level, and have threshold value damage when transmitting low level
It loses；According to the above characteristic, switch P1, switch P4 connection high level are managed using P；Metal-oxide-semiconductor N3, metal-oxide-semiconductor N4 connection low level, are adopted
It is managed with N；Switch P1, P2, P3, P4 are two groups of current mirrors pair, their working condition is managed by switch N1, N2 to be made, and work as OUT1
For high level, when OUT2 is low level, the leakage current of switch P3, N2 shutdown, switch P2 is I4, passes through mirror image, the electricity of switch P1
Flow the electric current that size is I4；If all switches all exactly match, then existing: I4=I1+I2+I3.
In figure time shaft t be by oscillator frequency f period of time T 0,1/4,1/2,3/4 ... interval drawn
Point；Corresponding to such a symmetrical circuit structure (I1=I2, R1=R2), 1/4 cycle of oscillation=CUC/ I1, therefore
Time cycle is T=4 (CUC/ I1)=4 (CR1/I3)/I1, therefore total oscillator frequency:
Circuit operation principle:
As shown in Figure 2, it is assumed that at the t=0 moment, charging capacitor C is a unsupported capacitor (UC=0), OUT1 is high electricity
Flat, since time point t=0, circuit enters the first relaxation estate, and current mirror circuit P1-P2 is access, NMOS transistor N3
It is similarly access, generates a voltage UR1=I3*R1 in first resistor R1；
Since NMOS transistor N4 is not guidable in first relaxation estate, and N13 and N14 under conditions of property at the same time
Be it is equivalent, it is defeated thus to there is pressure drop UR1 and difference amplifier of the identical grid source pressure drop on the time point resistance R1 of t=0
The pressure drop U87 entered between end is identical；
Because P1 pipe is connected, while P4 pipe shutdown (U12 > 0 at this time), the flow direction of present capacitor C charging current is VDD-P1-
C-I2-, the process of this charging constantly draws high the current potential of the anode of capacitor C and the positive terminal potential for inputting comparator is drawn
The pressure drop U87 of height, such amplifier in is correspondingly reduced, until t=T/4 moment capacitance voltage UC is charged to UR1=R1*
I3 and U87=0；
At the t=T/4 moment, conversion circuit is to the second relaxation estate, because U12 < 0, mirror circuit P1-P2 are closed now
Disconnected, current mirror circuit P3-P4 and NMOS transistor N2 are all connected, at this time U87 < 0, then occur voltage drop on resistance R2 now
UR2=R2*I3；
Thus capacitor C is discharged by the access on the ground VDD-P4-C-I1-, until t3=T/4 moment capacitance voltage is UC=-UR2
=-R2*I3, at this time U87=0.Circuit will be again introduced into the first relaxation estate in this way, and U87 is jumped again at this time, U12 > 0, UR1
=R1*I3 has arrived the t=T moment, and circuit is returned to the original state of UC=0；The oscillator cycle described before this is also corresponding
Continue on ground.
Illustrate the function of the application voltage controlled oscillator by the voltage waveform timing diagram of Fig. 3:
First curve for the t at any time of the institute making alive UC on capacitor C change curve；Wherein first transfer point (from
Be charged to the jump of electric discharge) at capacitance voltage UC be pressure drop (UC=R1*I3) on resistance R1, and at second transfer point
The voltage of (capacitor from the jump for discharging into charging) is identical as the pressure drop on R2 (UC=R2*I3).
Article 2 curve is the output plus terminal OUT1 of amplifier and the voltage difference U12 t at any time of the negative terminal OUT2 of output
Change curve, it can be seen that voltage absolute value of the difference constant OUT1 and OUT2 output are all that the square wave that duty ratio is 50% can be with
Directly it is linked as the output of oscillator.
Article 3 curve is the change curve of voltage UR1 on a timeline on resistance R1.
The change curve of the voltage UR2 that Article 4 curve is shown on resistance R2 t at any time can see on two resistance
Voltage drop be complementary relationship, when resistance R1 has electric current I3 to flow through the pressure drop to form UR1=R1*I3, on resistance R2 this
When no current is flowed through, pressure drop zero.Otherwise when resistance R2 has electric current I3 to flow through, when forming the pressure drop of UR2=R2*I3, resistance
No current is flowed through at this time on R1, pressure drop zero.
Article 5 curve is the situation of change that first order difference amplifier inputs voltage difference U87 t at any time on IN1IN2, can
To see that voltage U87 overvoltage zero point has a jump, this jump will be such that oscillator is converted between two transient state.
The decision formula of the temperature characterisitic frequency of frequency of oscillation are as follows:
Wherein I1 is the current mirror of the Iconst obtained in reference current module, thus I1 be one and temperature change without
The stabilization reference current of pass；Having I3 again is that the mirror image IRD of IRD is inversely proportional with resistanceElectric current, be strongly depend on resistance
Temperature coefficient, R1 and R9 be all polysilicon resistance, temperature coefficient having the same, therefore R1*I3 can offset theirs
Temperature coefficient, so available zero-temperature coefficient of frequency of oscillation.Controlled oscillator in the voltage controlled oscillator of the utility model
Completely new constant current charge-discharge oscillator is designed by cmos circuit, the electric current and resistance in frequency of oscillation can cancel out each other temperature
Coefficient, avoiding existing frequency of oscillation from being inversely proportional to the big PN junction forward conduction voltage of temperature drift leads to lacking for frequency of oscillation stability difference
Point has reached the zero-temperature coefficient for realizing frequency of oscillation, has improved the effect of the stability of frequency of oscillation.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this
Made any modification, equivalent replacement within the spirit and principle of utility model.
Claims (5)
1. a kind of voltage controlled oscillator, including control voltage module, current reference module and benchmark source module, the benchmark source module
Connect current reference module, the current reference module connection control voltage module, it is characterised in that: further include holohedral symmetry circuit
The controlled oscillator of structure, the control voltage module, current reference module and benchmark source module are separately connected controlled oscillator,
Export the square wave that frequency of oscillation is stable, duty ratio is 50%.
2. a kind of voltage controlled oscillator according to claim 1, it is characterised in that: the controlled oscillator includes that two-stage is symmetrical
Differential amplifier circuit, current mirror circuit, load resistance, capacitor and current source, the differential amplifier circuit input terminal and defeated
Outlet is separately connected current mirror circuit, and capacitor is connected between the current source, and described load resistance one end connects differential amplification
Circuit input end, the other end connect current mirror circuit.
3. a kind of voltage controlled oscillator according to claim 2, it is characterised in that: the differential amplifier circuit includes the first order
Differential amplifier circuit and second level differential amplifier circuit, the first order differential amplifier circuit include metal-oxide-semiconductor N9-N12, and described
Second level differential amplifier circuit includes metal-oxide-semiconductor N5-N8；The metal-oxide-semiconductor N11 is connected with metal-oxide-semiconductor N12 in mirror symmetry, the metal-oxide-semiconductor
N9 is connected with metal-oxide-semiconductor N10 in mirror symmetry, and the metal-oxide-semiconductor N11 grid connects input terminal IN1, the connection input of metal-oxide-semiconductor N12 grid
IN2 is held, the metal-oxide-semiconductor N9 and metal-oxide-semiconductor N10 grid, drain electrode are all connected with VDD, and the metal-oxide-semiconductor N9 source electrode is also connected with metal-oxide-semiconductor N8 grid
Pole, the metal-oxide-semiconductor N10 source electrode are also connected with metal-oxide-semiconductor N7 grid；The metal-oxide-semiconductor N5 is connected with metal-oxide-semiconductor N6 in mirror symmetry, described
Metal-oxide-semiconductor N7 is connected with metal-oxide-semiconductor N8 in mirror symmetry, and the metal-oxide-semiconductor N7 drain electrode connects output end OUT1, institute with metal-oxide-semiconductor N5 source electrode
Output end OUT1 connection current mirror circuit one end is stated, the metal-oxide-semiconductor N8 drain electrode connects output end OUT2 with metal-oxide-semiconductor N8 source electrode,
The output end OUT1 connection current mirror circuit other end, the metal-oxide-semiconductor N5 and metal-oxide-semiconductor N6 grid, drain electrode are all connected with VDD,
Realize holohedral symmetry differential amplification.
4. a kind of voltage controlled oscillator according to claim 2 or 3, it is characterised in that: the current mirror circuit includes
Current mirror is to P1P2, current mirror to P3P4, control switch group N1N2 and switching group N3N4, the switch of the switching group N3N4
N3 grid, N4 grid are separately connected output end OUT1, output end OUT2, and switch N3 source electrode, switch N4 source electrode are all connected with current source
It is grounded after I6, switch N3 drain electrode drains to the switch P1 in P1P2 via load resistance R1 connection current mirror, current mirror pair
In P1P2 switch P1, P2 mirror symmetry connection, grid connection after connect control switch group N1N2, source electrode connection after
VDD is connected, switch N4 drain electrode drains to the switch P4 in P3P4 via load resistance R2 connection current mirror, current mirror pair
In P3P4 switch P3, P4 mirror symmetry connection, grid connection after connect control switch group N1N2, source electrode connection after
Connect VDD；Load resistance is grounded after being also connected with current source I2 via being grounded after capacitor C connection current source I2；Load resistance warp
By being grounded after capacitor C connection current source I1, it is grounded after being also connected with current source I2, being realized by the on-off of current mirror circuit will
Differential amplifier circuit is exported, and realizes charge and discharge electric oscillation.
5. a kind of voltage controlled oscillator according to claim 4, it is characterised in that: control switch group N1N2 includes metal-oxide-semiconductor N1
With metal-oxide-semiconductor N2, the metal-oxide-semiconductor N1 source electrode and metal-oxide-semiconductor N2 source electrode are grounded after being all connected with current source I4, and metal-oxide-semiconductor N1 drain electrode connection is opened
P2 drain electrode, metal-oxide-semiconductor N2 drain electrode connection switch P3 drain electrode are closed, metal-oxide-semiconductor N1 grid connects metal-oxide-semiconductor N3 grid, the connection of metal-oxide-semiconductor N2 grid
Metal-oxide-semiconductor N4 grid, for controlling current mirror P1P2 and P3P4 to working condition.
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| CN201822153623.9U CN209105124U (en) | 2018-12-20 | 2018-12-20 | A kind of voltage controlled oscillator |
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| CN201822153623.9U CN209105124U (en) | 2018-12-20 | 2018-12-20 | A kind of voltage controlled oscillator |
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