CN101401298A - Frequency converting circuit - Google Patents

Frequency converting circuit Download PDF

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Publication number
CN101401298A
CN101401298A CN200680053933.0A CN200680053933A CN101401298A CN 101401298 A CN101401298 A CN 101401298A CN 200680053933 A CN200680053933 A CN 200680053933A CN 101401298 A CN101401298 A CN 101401298A
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China
Prior art keywords
differential amplifier
switch
differential
switch circuit
input
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Pending
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CN200680053933.0A
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Chinese (zh)
Inventor
石黑和久
高桥义昭
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NIIGATO PRECISION CO Ltd
NSC Co Ltd
Ricoh Co Ltd
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NIIGATO PRECISION CO Ltd
Ricoh Co Ltd
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Publication of CN101401298A publication Critical patent/CN101401298A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/14—Balanced arrangements
    • H03D7/1425—Balanced arrangements with transistors
    • H03D7/1441—Balanced arrangements with transistors using field-effect transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/14—Balanced arrangements
    • H03D7/1425—Balanced arrangements with transistors
    • H03D7/1458—Double balanced arrangements, i.e. where both input signals are differential
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/14—Balanced arrangements
    • H03D7/1425—Balanced arrangements with transistors
    • H03D7/1466—Passive mixer arrangements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/16—Multiple-frequency-changing
    • H03D7/165—Multiple-frequency-changing at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D2200/00—Indexing scheme relating to details of demodulation or transference of modulation from one carrier to another covered by H03D
    • H03D2200/0041—Functional aspects of demodulators
    • H03D2200/0084—Lowering the supply voltage and saving power

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

A single constant current source (IO) is connected, in a common source fashion, to first and second differential amplifiers (10I,10Q) that perform a differential amplification based on the same input signal. The single constant current source (IO) is used to drive both of the differential amplifiers (10I,10Q), thereby establishing an appropriate gain of each of the differential amplifiers (10I,10Q) so as to obtain a desired noise factor (NF). Additionally, the arrangement in which these differential amplifiers (10I,10Q) operate only by use of the single constant current source (IO) can suppress the increase of current consumption though the two differential amplifiers are existent.

Description

Freq converting circuit
Technical field
The present invention relates to a kind of freq converting circuit, more particularly, relate to a kind of freq converting circuit that is suitable for constituting the IQ frequency mixer of quadrature modulator.
Background technology
In the past, as the freq converting circuit that constitutes, the freq converting circuit (for example, with reference to patent documentation 1) of use Gilbert cell (Gilbert cell) and the freq converting circuit that uses the MOS switch are arranged on the MOS integrated circuit, this is that people are known.
Patent documentation 1: the spy opens flat 10-No. 200337 communiques
Usually, the IQ frequency mixer of formation quadrature modulator can have the Gilbert cell type frequency mixer of a plurality of Gilbert cells or combination to have the passive frequency mixer of a plurality of MOS switchs to constitute by combination.Fig. 1 is the figure that the formation of Gilbert cell type IQ frequency mixer in the past is shown.Fig. 2 is the figure that the formation of passive IQ frequency mixer in the past is shown.
As shown in Figure 1, Gilbert cell type IQ frequency mixer is equipped with two Gilbert cells 50 IWith 50 QAbout being used for the Gilbert cell 50 of in-phase signal (I signal) I, be in the input signal V that phase place departs from 180 degree states mutually IN, V INThe input terminal of-(-expression phase phasic difference 180 degree) between, dispose and comprise 1 group of differential transistor (M1 I, M2 I) first differential amplifier 51 IThis first differential amplifier 51 IBy the first constant-current supply I 1Drive.And, be in this locality (local) signal V that phase place departs from the state of 180 degree mutually I, V I-input terminal between, dispose and comprise two groups of differential transistors { (M3 I, M4 I), (M5 I, M6 I) first mixer 52 of doubly balanced type I
First mixer 52 ISpecifically constitute according to the following stated.That is, a side differential transistor is to (M3 I, M4 I) drain electrode between and the opposing party's differential transistor to (M5 I, M6 I) drain electrode between respectively common connection.And, transistor M3 IGrid and transistor M6 IGrid commonly connect counter-rotating local signal V I-be input to this common grid.And, transistor M4 IGrid and transistor M5 IGrid commonly connect local signal V IBe input to this common grid.And, each transistor M3 I, M4 I, M5 I, M6 ISource electrode be connected to power vd D.
And, first differential amplifier 51 ISpecifically constitute according to the following stated.That is, about a side transistor M1 I, its drain electrode and a side's differential transistor is to (M3 I, M4 I) common drain electrode be connected the source electrode and the first constant-current supply I 1Be connected.Input signal V INInput to grid.And, about the opposing party's transistor M2 I, its drain electrode and the opposing party's differential transistor is to (M5 I, M6 I) common drain electrode be connected the source electrode and the first constant-current supply I 1Be connected.Inversion input signal V IN-input to grid.
Similarly, about being used for the Gilbert cell 50 of orthogonal signalling (Q signal) Q, be in the input signal V that phase place departs from the state of 180 degree mutually IN, V IN-input terminal between, dispose and comprise 1 group of differential transistor (M1 Q, M2 Q) second differential amplifier 51 QThis second differential amplifier 51 QBy the second constant-current supply I 2Drive.And, be in the local signal V that phase place departs from the state of 180 degree mutually Q, V Q-input terminal between, dispose and comprise two groups of differential transistors { (M3 Q, M4 Q), (M5 Q, M6 Q) second mixer 52 of doubly balanced type Q
Second mixer 52 QSpecifically constitute according to the following stated.That is, a side differential transistor is to (M3 Q, M4 Q) drain electrode between and the opposing party's differential transistor to (M5 Q, M6 Q) drain electrode between respectively common connection.And, transistor M3 QGrid and transistor M6 QGrid commonly connect counter-rotating local signal V Q-be input to this common grid.And, transistor M4 QGrid and transistor M5 QGrid commonly connect local signal V QBe input to this common grid.And, each transistor M3 Q, M4 Q, M5 Q, M6 QSource electrode be connected to power vd D.
And, second differential amplifier 51 QSpecifically constitute according to the following stated.That is, about a side transistor M1 Q, its drain electrode and a side's differential transistor is to (M3 Q, M4 Q) common drain electrode be connected the source electrode and the second constant-current supply I 2Be connected.Input signal V INInput to grid.And, about the opposing party's transistor M2 Q, its drain electrode and the opposing party's differential transistor is to (M5 Q, M6 Q) common drain electrode be connected the source electrode and the second constant-current supply I 2Be connected.Inversion input signal V IN-input to grid.
In the Gilbert cell type IQ frequency mixer that constitutes like this, input signal V INAnd V IN-be input to first and second differential amplifier 51 IWith 51 Q, its output is imported into first and second mixer 52 IWith 52 QAnd, from first mixer 52 IOutput in extract phase place differ mutually 180 the degree in-phase signal I and I-, from second mixer 52 QOutput in extract phase place differ mutually 180 the degree orthogonal signalling Q and Q-.
And, two switch circuits 60 are equipped with as shown in Figure 2, in the passive IQ frequency mixer, IWith 60 QAbout the switch circuit 60 that is used for in-phase signal I, input signal V INBe input to first and second switch SW1 IAnd SW2 IAnd, be in phase place with respect to input signal V INThe inversion input signal V that departs from the state of 180 degree IN-be input to the 3rd and the 4th switch SW3 IAnd SW4 I
About second and third switch SW2 IAnd SW3 I, connect (ON)/cut off (OFF) according to local signal V IControl.And, about the first and the 4th switch SW1 IAnd SW4 I, connection/cut-out is according to being in phase place with respect to local signal V IThe counter-rotating local signal V that departs from the state of 180 degree I-control.And, the first and the 3rd switch SW1 IAnd SW3 IOutput by mixing, meanwhile, the second and the 4th switch SW2 IAnd SW4 IOutput by mixing, as in-phase signal I and I-and be extracted out.
And, about the switch circuit 60 that is used for orthogonal signalling Q, input signal V INBe input to first and second switch SW1 QAnd SW2 QAnd, be in phase place with respect to input signal V INThe inversion input signal V that departs from the state of 180 degree IN-be input to the 3rd and the 4th switch SW3 QAnd SW4 Q
About second and third switch SW2 QAnd SW3 Q, connection/cut-out is according to local signal V QControl.And, about the first and the 4th switch SW1 QAnd SW4 Q, connection/cut-out is according to being in phase place with respect to local signal V QThe counter-rotating local signal V that departs from the state of 180 degree Q-control.And, the first and the 3rd switch SW1 QAnd SW3 QOutput by mixing, meanwhile, the second and the 4th switch SW2 QAnd SW4 QOutput by mixing, as orthogonal signalling Q and Q-and be extracted out.
Under the situation of Gilbert cell type IQ frequency mixer shown in Figure 1, it gains by differential amplifier 51 IWith 51 QMutual conductance gm and load impedance determine.Therefore, can set the NF (noise figure) of suitable gain to obtain to wish.But there are the following problems: in order to extract in-phase signal and orthogonal signalling, need two Gilbert cells 50 IWith 50 Q, and, compare with a simple mixer, need the current sinking of twice.
On the other hand, under the situation of passive IQ frequency mixer shown in Figure 2, owing to there is not direct current to flow in the mixing unit, therefore, current sinking is zero.But, since do not have can ride gain differential amplifier, therefore gain is roughly 1 (0[dB]).Therefore, can not obtain desirable NF, have the problem of NF deterioration.
Summary of the invention
Make the present invention in order to address the above problem, purpose provides a kind of freq converting circuit that can realize little current sinking and good noise figure NF.
In order to address the above problem, in freq converting circuit of the present invention, for first differential amplifier and second differential amplifier of carrying out differential amplifieroperation based on identical input signal, commonly connect a constant-current supply by common source, two sides' differential amplifier is driven by a constant-current supply.
And, can be by of the combination of above-mentioned first and second differential amplifier with first and second switch circuit that is connected with their output, constitute freq converting circuit, and based on phase place differ mutually 90 the degree local signals drive above-mentioned first and second switch circuit respectively.
The present invention according to constituting as mentioned above in first and second differential amplifier, can set suitable gain to obtain desirable noise figure NF.And, owing to these differential amplifiers are only operated by a constant-current supply, even therefore have the increase that two differential amplifiers still can suppress current sinking.
Description of drawings
Fig. 1 illustrates the formation of Gilbert cell type IQ frequency mixer in the past.
Fig. 2 illustrates the formation of passive IQ frequency mixer in the past.
Fig. 3 illustrates the formation example according to the freq converting circuit of present embodiment.
Fig. 4 illustrates the operating current according to the freq converting circuit of present embodiment.
Fig. 5 illustrates another formation example according to the freq converting circuit of present embodiment.
Embodiment
Below, based on accompanying drawing one embodiment of the present of invention are described.Fig. 3 illustrates the formation example according to the freq converting circuit of present embodiment.As shown in Figure 3, the freq converting circuit of present embodiment is equipped with two differential amplifiers 10 IWith 10 Q, and two switch circuits 20 IWith 20 Q
First differential amplifier 10 IComprise 1 group of differential transistor to (M1 I, M2 I), carry out for the input signal V that differ 180 degree from two input terminals 1 and 2 inputs and phase place mutually INAnd V IN-differential amplifieroperation.And, second differential amplifier 10 QComprise 1 group of differential transistor to (M1 Q, M2 Q), with first differential amplifier 10 ISimilarly also for signal V from two input terminals 1 and 2 inputs INAnd V IN-carry out differential amplifieroperation.
First differential amplifier 10 IConstitute according to as described below.That is, about a side transistor M1 I, its drain electrode and first switch circuit 20 IFirst and second switch SW1 IAnd SW2 IBe connected, source electrode is connected to constant-current supply I 0Grid and input signal V INInput terminal 1 be connected.And, about the opposing party's transistor M2 I, its drain electrode and first switch circuit 20 IThe the 3rd and the 4th switch SW3 IAnd SW4 IBe connected, source electrode is connected to constant-current supply I 0Grid and inversion input signal V IN-input terminal 2 be connected.
And, second differential amplifier 10 QAccording to formation as described below.That is, about a side transistor M1 Q, its drain electrode and second switch circuit 20 QFirst and second switch SW1 QAnd SW2 QBe connected, source electrode is connected to constant-current supply I 0Grid and input signal V INInput terminal 1 be connected.And, about the opposing party's transistor M2 Q, its drain electrode and second switch circuit 20 QThe the 3rd and the 4th switch SW3 QAnd SW4 QBe connected, source electrode is connected to constant-current supply I 0Grid and inversion input signal V IN-input terminal 2 be connected.
So, under the situation of present embodiment, constitute first and second differential amplifier 10 IWith 10 Q4 transistor M1 I, M2 I, M1 Q, M2 QSource electrode commonly connect its common source and a constant-current supply I 0Commonly connect.And, first differential amplifier 10 IAnd second differential amplifier 10 QBy a constant-current supply I 0Drive.
First switch circuit 20 IFirst to fourth switch SW1 is equipped with ITo SW4 IThe first switch SW1 IWith the 3rd switch SW3 IBe connected first differential amplifier 10 IOutput and the lead-out terminal 3 of in-phase signal I between.Thus, constitute first differential amplifier 10 IEach transistor M1 IAnd M2 IOutput by mixing, extract from lead-out terminal 3 as in-phase signal I.And, the first switch SW1 IWith the 3rd switch SW3 IOutput via impedance R1 IAnd be connected to power vd D.
And, the second switch SW2 IWith the 4th switch SW4 IBe connected first differential amplifier 10 IOutput and counter-rotating in-phase signal I-lead-out terminal 4 between, constitute first differential amplifier 10 IEach transistor M1 IAnd M2 IOutput by mixing, as counter-rotating in-phase signal I-and extract from lead-out terminal 4.And, the second switch SW2 IWith the 4th switch SW4 IOutput via impedance R2 IAnd be connected to power vd D.
Thus, the second switch SW2 IWith the 3rd switch SW3 IBy the local signal V that imports from a side local input terminal 5 IDrive its connection/cut-out Be Controlled.And, the first switch SW1 IWith the 4th switch SW4 IBy being in phase place with respect to local signal V IThe counter-rotating local signal V that departs from the state of 180 degree I-drive its connection/cut-out Be Controlled.This counter-rotating local signal V I-import from the opposing party's local input terminal 6.
Similarly, second switch circuit 20 QFirst to fourth switch SW1 is equipped with QTo SW4 QThe first switch SW1 QWith the 3rd switch SW3 QBe connected second differential amplifier 10 QOutput and the lead-out terminal 7 of orthogonal signalling Q between.Thus, constitute second differential amplifier 10 QEach transistor M1 QAnd M2 QOutput by mixing, extract from lead-out terminal 7 as orthogonal signalling Q.And, the first switch SW1 QWith the 3rd switch SW3 QOutput via impedance R1 QAnd be connected to power vd D.
And, the second switch SW2 QWith the 4th switch SW4 QBe connected second differential amplifier 10 QOutput and counter-rotating orthogonal signalling Q-lead-out terminal 8 between, constitute second differential amplifier 10 QEach transistor M1 QAnd M2 QOutput by mixing, as counter-rotating orthogonal signalling Q-and extract from lead-out terminal 8.And, the second switch SW2 QWith the 4th switch SW4 QOutput via impedance R2 QAnd be connected to power vd D.
Thus, the second switch SW2 QWith the 3rd switch SW3 QBy the local signal V that imports from a side local input terminal 9 QDrive its connection/cut-out Be Controlled.And, the first switch SW1 QWith the 4th switch SW4 QBy being in phase place with respect to local signal V QThe counter-rotating local signal V that departs from the state of 180 degree Q-drive its connection/cut-out Be Controlled.This counter-rotating local signal V Q-import from the opposing party's local input terminal 10.
Fig. 4 illustrates the operating current according to the freq converting circuit of the mentioned above and present embodiment that constitutes.As mentioned above, at differential amplifier 10 IWith 10 QThe rear end connect the switch circuit 20 of MOS IWith 20 Q, because this switch circuit 20 IWith 20 QLocal signal by phase phasic difference 90 degree drives (V IAnd V QAnd V I-and V Q-phase phasic difference 90 is spent respectively), at differential amplifier 10 IWith 10 QEach transistor M1 I, M2 I, M1 Q, M2 QThe vector of the signal code that flows as shown in Figure 4.
In Fig. 4, I iBe to utilize first differential amplifier 10 IGenerate in-phase signal I and I-necessary electric current, I qBe to utilize second differential amplifier 10 QGenerate orthogonal signalling Q and Q-necessary electric current.At this, I i=I qIn the case, with these differential amplifiers 10 IWith 10 QConstant-current supply I by the common source connection 0Middle necessary electric current I 0, that is, and the common current I of necessity in the circuit of Fig. 3 0For
I 0 = 2 I t . On the other hand, the signal code I of necessity in the example in the past of Fig. 1 4For
I 4＝I 1+I 2＝I i+I q＝2I i。Therefore, according to present embodiment, can realize the IQ frequency mixer by about 70% current sinking of example in the past.
And, in the present embodiment, owing to can set differential amplifier 10 IWith 10 QGain so that can guarantee desirable noise figure NF, therefore, can be suppressed at the deterioration that becomes the noise figure NF of problem under the situation of the such passive IQ frequency mixer of as shown in Figure 2 example in the past.
And, although in the above-described embodiments, differential amplifier 10 IWith 10 QThe common source limit via constant-current supply I 0And be connected to the virtual ground point, yet be not limited to this.Because input signal V INAnd V IN-phase phasic difference 180 degree, therefore also can ground connection.In the case, low voltage operating can further improve.
Fig. 5 illustrates another formation example according to the freq converting circuit of present embodiment.Freq converting circuit shown in Figure 5 illustrates the formation example of situation that input signal self comprises the combination of in-phase signal and orthogonal signalling.And, in this Fig. 5, give identical label to the composed component that has with composed component identical functions shown in Figure 3.Freq converting circuit shown in Figure 5 is equipped with 4 differential amplifiers 10 I, 10 Q, 11 I, 11 QAnd 4 switch circuits 20 I, 20 Q, 21 I, 21 Q
First differential amplifier 10 IComprise 1 group of differential transistor to (M1 I, M2 I), carry out for the input in-phase signal V that differ 180 degree from two input terminals 1 and 2 inputs and phase place mutually INI and V INI-differential amplifieroperation.And, second differential amplifier 10 QComprise 1 group of differential transistor to (M1 Q, M2 Q), carry out for differing the 180 input orthogonal signalling V that spend mutually from two input terminals 1 ' and 2 ' input and phase place INQ and V INQ-differential amplifieroperation.
And, the 3rd differential amplifier 11 IComprise 1 group of differential transistor to (M3 I, M4 I), with first differential amplifier 10 ISimilarly also for in-phase signal V from two input terminals 1 and 2 inputs INI and V INThe differential amplifieroperation of I-carry out.And, the 4th differential amplifier 11 QComprise 1 group of differential transistor to (M3 Q, M4 Q), with second differential amplifier 10 QSimilarly also for orthogonal signalling V from two input terminals 1 ' and 2 ' input INQ and V INThe differential amplifieroperation of Q-carry out.
First differential amplifier 10 IAccording to formation as described below.That is, about a side transistor M1 I, its drain electrode and first switch circuit 20 IFirst and second switch SW1 I1And SW2 I1Be connected, source electrode is connected to constant-current supply I 0Grid and input in-phase signal V INThe input terminal 1 of I is connected.And, about the opposing party's transistor M2 I, its drain electrode and first switch circuit 20 IThe the 3rd and the 4th switch SW3 I1And SW4 I1Be connected, source electrode is connected to constant-current supply I 0Grid and counter-rotating input in-phase signal V INI-input terminal 2 be connected.
And, second differential amplifier 10 QConstitute according to as described below.That is, about a side transistor M1 Q, its drain electrode and second switch circuit 20 QFirst and second switch SW1 Q1And SW2 Q1Be connected, source electrode is connected to constant-current supply I 0Grid and input orthogonal signalling V INThe input terminal 1 ' of Q is connected.And, about the opposing party's transistor M2 Q, its drain electrode and second switch circuit 20 QThe the 3rd and the 4th switch SW3 Q1And SW4 Q1Be connected, source electrode is connected to constant-current supply I 0Grid and counter-rotating input orthogonal signalling V INQ-input terminal 2 ' be connected.
The 3rd differential amplifier 11 IConstitute according to as described below.That is, about a side transistor M3 I, its drain electrode and the 3rd switch circuit 21 IFirst and second switch SW1 I2And SW2 I2Be connected, source electrode is connected to constant-current supply I 0Grid and input in-phase signal V INThe input terminal 1 of I is connected.And, about the opposing party's transistor M4 I, its drain electrode and the 3rd switch circuit 21 IThe the 3rd and the 4th switch SW3 I2And SW4 I2Be connected, source electrode is connected to constant-current supply I 0Grid and counter-rotating input in-phase signal V INI-input terminal 2 be connected.
And, the 4th differential amplifier 11 QAccording to formation as described below.That is, about a side transistor M3 Q, its drain electrode and the 4th switch circuit 21 QFirst and second switch SW1 Q2And SW2 Q2Be connected, source electrode is connected to constant-current supply I 0Grid and input orthogonal signalling V INThe input terminal 1 ' of Q is connected.And, about the opposing party's transistor M4 Q, its drain electrode and the 4th switch circuit 21 QThe the 3rd and the 4th switch SW3 Q2And SW4 Q2Be connected, source electrode is connected to constant-current supply I 0Grid and counter-rotating input orthogonal signalling V INQ-input terminal 2 ' be connected.
So, under the situation of freq converting circuit shown in Figure 5, constitute first to fourth differential amplifier 10 I, 10 Q, 11 I, 11 Q8 transistor M1 I, M2 I, M3 I, M4 I, M1 Q, M2 Q, M3 Q, M4 QSource electrode commonly connect its common source and a constant-current supply I 0Commonly connect.And, first to fourth differential amplifier 10 I, 10 Q, 11 I, 11 QBy a constant-current supply I 0Drive.
First switch circuit 20 IFirst to fourth switch SW1 is equipped with I1To SW4 I1The first switch SW1 I1With the 3rd switch SW3 I1Be connected first differential amplifier 10 IThe output and the first in-phase signal I 1Lead-out terminal 3 between.Thus, constitute first differential amplifier 10 IEach transistor M1 IAnd M2 IOutput by mixing, as the first in-phase signal I 1And extract from lead-out terminal 3.And, the first switch SW1 I1With the 3rd switch SW3 I1Output via impedance R1 IAnd be connected to power vd D.
And, the second switch SW2 I1With the 4th switch SW4 I1Be connected first differential amplifier 10 IThe output and the first counter-rotating in-phase signal I 1-lead-out terminal 4 between.Thus, constitute first differential amplifier 10 IEach transistor M1 IAnd M2 IOutput by mixing, as the first counter-rotating in-phase signal I 1-and extract from lead-out terminal 4.And, the second switch SW2 I1With the 4th switch SW4 I1Output via impedance R2 IAnd be connected to power vd D.
Thus, the second switch SW2 I1With the 3rd switch SW3 I1By the local signal V that imports from a side local input terminal 5 IDrive its connection/cut-out Be Controlled.And, the first switch SW1 I1With the 4th switch SW4 I1By being in phase place with respect to local signal V IThe counter-rotating local signal V that departs from the state of 180 degree I-drive its connection/cut-out Be Controlled.This counter-rotating local signal V I-import from the opposing party's local input terminal 6.
Similarly, second switch circuit 20 QFirst to fourth switch SW1 is equipped with Q1To SW4 Q1The first switch SW1 Q1With the 3rd switch SW3 Q1Be connected second differential amplifier 10 QThe output and the first orthogonal signalling Q 1Lead-out terminal 7 between.Thus, constitute second differential amplifier 10 QEach transistor M1 QAnd M2 QOutput by mixing, as the first orthogonal signalling Q 1And extract from lead-out terminal 7.And, the first switch SW1 Q1With the 3rd switch SW3 Q1Output via impedance R1 QAnd be connected to power vd D.
And, the second switch SW2 Q1With the 4th switch SW4 Q1Be connected second differential amplifier 10 QThe output and the first counter-rotating orthogonal signalling Q 1-lead-out terminal 8 between.Thus, constitute second differential amplifier 10 QEach transistor M1 Q1And M2 Q1Output by mixing, as the first counter-rotating orthogonal signalling Q 1-and extract from lead-out terminal 8.And, the second switch SW2 Q1With the 4th switch SW4 Q1Output via impedance R2 QAnd be connected to power vd D.
Thus, the second switch SW2 Q1With the 3rd switch SW3 Q1By the local signal V that imports from a side local input terminal 9 QDrive its connection/cut-out Be Controlled.And, the first switch SW1 Q1With the 4th switch SW4 Q1By being in phase place with respect to local signal V QThe counter-rotating local signal V that departs from the state of 180 degree Q-drive its connection/cut-out Be Controlled.This counter-rotating local signal V Q-import from the opposing party's local input terminal 10.
Similarly, the 3rd switch circuit 21 IFirst to fourth switch SW1 is equipped with I2To SW4 I2The first switch SW1 I2With the 3rd switch SW3 I2Be connected the 3rd differential amplifier 11 IThe output and the second in-phase signal I 2Lead-out terminal 3 ' between.Thus, constitute the 3rd differential amplifier 11 IEach transistor M3 IAnd M4 IOutput by mixing, as the second in-phase signal I 2And extract from lead-out terminal 3.And, the first switch SW1 I2With the 3rd switch SW3 I2Output via impedance R3 IAnd be connected to power vd D.
And, the second switch SW2 I2With the 4th switch SW4 I2Be connected the 3rd differential amplifier 11 IThe output and the second counter-rotating in-phase signal I 2-lead-out terminal 4 ' between.Thus, constitute the 3rd differential amplifier 11 IEach transistor M3 IAnd M4 IOutput by mixing, as the second counter-rotating in-phase signal I 2-and extract from lead-out terminal 4 '.And, the second switch SW2 I2With the 4th switch SW4 I2Output via impedance R4 IAnd be connected to power vd D.
Thus, the second switch SW2 I2With the 3rd switch SW3 I2By counter-rotating local signal V from the local input terminal 5 ' input of a side counter-rotating I-drive its connection/cut-out Be Controlled.And, the first switch SW1 I2With the 4th switch SW4 I2By being in phase place with respect to counter-rotating local signal V I-depart from the local signal V of states of 180 degree IDrive its connection/cut-out Be Controlled.This local signal V IImport from the local input terminal 6 ' of the opposing party's counter-rotating.
Similarly, the 4th switch circuit 21 QFirst to fourth switch SW1 is equipped with Q2To SW4 Q2The first switch SW1 Q2With the 3rd switch SW3 Q2Be connected the 4th differential amplifier 11 QThe output and the second orthogonal signalling Q 2Lead-out terminal 7 ' between.Thus, constitute the 4th differential amplifier 11 QEach transistor M3 QAnd M4 QOutput by mixing, as the second orthogonal signalling Q 2And extract from lead-out terminal 7 '.And, the first switch SW1 Q2With the 3rd switch SW3 Q2Output via impedance R3 QAnd be connected to power vd D.
And, the second switch SW2 Q2With the 4th switch SW4 Q2Be connected the 4th differential amplifier 11 QThe output and the second counter-rotating orthogonal signalling Q 2-lead-out terminal 8 ' between.Thus, constitute the 4th differential amplifier 11 QEach transistor M3 Q2And M4 Q2Output by mixing, as the second counter-rotating orthogonal signalling Q 2-and extract from lead-out terminal 8 '.And, the second switch SW2 Q2With the 4th switch SW4 Q2Output via impedance R4 QAnd be connected to power vd D.
Thus, the second switch SW2 Q2With the 3rd switch SW3 Q2By counter-rotating local signal V from the local input terminal 9 ' input of a side counter-rotating Q-drive its connection/cut-out Be Controlled.And, the first switch SW1 Q2With the 4th switch SW4 Q2By being in phase place with respect to counter-rotating local signal V Q-depart from the local signal V of states of 180 degree QDrive its connection/cut-out Be Controlled.This local signal V QImport from the local input terminal 10 ' of the opposing party's counter-rotating.
Under the situation that constitutes above-mentioned freq converting circuit shown in Figure 5, with each differential amplifier 10 I, 10 Q, 11 I, 11 QConstant-current supply I by the common source connection 0Middle necessary electric current I 0, that is, and the common current I of necessity in the circuit of Fig. 5 0For
I 0 = 2 2 I i = 2 I i . On the other hand, under the situation of the IQ frequency mixer that constitutes the such common Gilbert cell of example in the past, because the circuit of essential two Fig. 1, therefore, necessary signal code I 4For
I 4＝2(I 1+I 2)＝4I i。Therefore, according to present embodiment, can realize the IQ frequency mixer by 50% current sinking of example in the past.
And, though in freq converting circuit shown in Figure 5, about 8 transistor M1 I, M2 I, M3 I, M4 I, M1 Q, M2 Q, M3 Q, M4 QAll be connected to a constant-current supply I with common source 0Example describe, yet, must all not be set to common source by 8 transistors.
And, though in the above-described embodiments, the example that constitutes freq converting circuit about the combination of differential amplifier by linear operation and MOS switch describes, yet, also can be that a plurality of differential amplifiers are connected to constant-current supply by common source in Gilbert cell type IQ frequency mixer.
In addition, the foregoing description only illustrates implements a specific example of the present invention arbitrarily, but not comes in view of the above technical scope of the present invention is carried out explaining limitedly.That is, the present invention does not break away from its spirit or its principal character, can implement with various forms.
The following describes industrial applicibility of the present invention.
The present invention can be used in the IQ frequency mixer that consists of quadrature modulator.

Claims (5)

1. freq converting circuit comprises:
First differential amplifier is carried out differential amplifieroperation for the signal that differs 180 degree mutually from two input terminal inputs, phase places;
Second differential amplifier is similarly also carried out differential amplifieroperation for the signal of importing from described two input terminals with described first differential amplifier;
Wherein, the transistorized source electrode that constitutes the transistorized source electrode of described first differential amplifier and constitute described second differential amplifier commonly is connected to a constant-current supply, and described first differential amplifier and described second differential amplifier are driven by a described constant-current supply.
2. freq converting circuit comprises:
First differential amplifier and second differential amplifier commonly are connected to a constant-current supply, respectively phase place are differed 180 input signals of spending mutually and carry out differential amplifieroperation;
First switch circuit and second switch circuit are connected to the output of described first differential amplifier and described second differential amplifier, respectively based on phase place differ mutually 90 the degree local signals and be driven;
Wherein, from the output of described first switch circuit and described second switch circuit, extract in-phase signal and orthogonal signalling.
3. according to the described freq converting circuit of claim 2, it is characterized in that described first differential amplifier and described second differential amplifier are connected to the virtual ground point via a described constant-current supply.
4. according to the described freq converting circuit of claim 2, it is characterized in that described first differential amplifier and described second differential amplifier are connected to earth point via a described constant-current supply.
5. freq converting circuit comprises:
First differential amplifier and the 3rd differential amplifier commonly are connected to a constant-current supply, respectively phase place are differed the 180 input in-phase signals of spending mutually and carry out differential amplifieroperation;
Second differential amplifier and the 4th differential amplifier commonly are connected to a constant-current supply, respectively phase place are differed the 180 input orthogonal signalling of spending mutually and carry out differential amplifieroperation;
First switch circuit and second switch circuit are connected to the output of described first differential amplifier and described second differential amplifier, respectively based on phase place differ mutually 90 the degree local in-phase signals and be driven;
The 3rd switch circuit and the 4th switch circuit are connected to the output of described the 3rd differential amplifier and described the 4th differential amplifier, respectively based on phase place differ mutually 90 the degree local orthogonal signalling and be driven;
Wherein, from the output of described first switch circuit and described the 3rd switch circuit, extract the in-phase signal of two kinds, and the orthogonal signalling that from the output of described second switch circuit and described the 4th switch circuit, extract two kinds.
CN200680053933.0A 2006-03-22 2006-11-08 Frequency converting circuit Pending CN101401298A (en)

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JP2006078048A JP2007258861A (en) 2006-03-22 2006-03-22 Frequency conversion circuit
JP078048/2006 2006-03-22

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US8229043B2 (en) 2008-03-21 2012-07-24 Qualcomm Incorporated Stepped gain mixer

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JP2001257538A (en) * 2000-03-14 2001-09-21 Nippon Telegr & Teleph Corp <Ntt> Orthogonal mixer circuit and complex mixer circuit
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