CN103956982B - Common-mode feedback circuit for duration of two-stage differential amplifier - Google Patents
Common-mode feedback circuit for duration of two-stage differential amplifier Download PDFInfo
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Abstract
The invention discloses a common-mode feedback circuit for duration of a two-stage differential amplifier. The common-mode feedback circuit comprises a two-stage differential amplifier, a common-mode voltage detecting unit and a common-mode feedback control signal generating unit, wherein the common-mode voltage detecting unit is used for detecting the output common-mode voltage of the two-stage differential amplifier; the common-mode feedback control signal generating unit is used for controlling the first-stage current source loading of the two-stage differential amplifier to be stable at a pre-arranged direct-current operation point; two outputs of the two-stage differential amplifier are connected with the common-mode voltage detecting unit respectively; the output of the common-mode voltage detecting unit is connected with the common-mode feedback control signal generating unit; the two outputs of the common-mode feedback control signal generating unit are connected with the first stage current source loading of the two-stage differential amplifier respectively. According to the invention, a 'dead lock' condition is prevented from occurring to the two-stage differential amplifier when the two-stage differential amplifier is in closed-loop application, and a prodigious transient value is emerged in the input common-mode signal.
Description
Technical field
The present invention relates to field of analog integrated circuit, more particularly to a kind of continuous time for two-stage differential amplifier is altogether
Cmfb circuit.
Background technology
As two-stage differential amplifier has, output voltage swing is big, common mode noise rejection is good, and can effectively suppress even
The advantages of secondary item harmonic distortion, have been obtained for extensive utilization.Common mode feedback circuit is indispensable in Differential OPAMP
One Key Circuit, its objective is the DC level of each node inside stable difference amplifier, it is ensured that transistor works
In saturation, and the output common mode level of precise control difference amplifier, it is optimal the output voltage swing of amplifier.Common mode
Feedback circuit also helps the common mode fluctuation of rejective amplifier, improves its common mode rejection ratio.
Fig. 1 is 100 schematic diagram of two-stage differential amplifier using existing common mode feedback circuit, and see reference document 1.Such as Fig. 1
Shown, this detects circuit 101 (equivalent to the present invention by common mode using the two-stage differential amplifier 100 of existing common mode feedback circuit
Common-mode voltage detector unit 201), common-mode feedback control signal produces circuit 102 and (controls equivalent to the common-mode feedback of the present invention
202) signal generation unit is constituted with two-stage differential amplifier, detects that circuit 101 detects the two-stage differential and amplifies by common mode
The output common mode level (being designated as Vocm1, Vocm1=(Von1+Vop1)/2) of device, the output common mode voltage (Vocm1) with this two
The difference of the desired output common-mode voltage (being designated as Vcm1) of level difference amplifier produces circuit 102 through common-mode feedback control signal
It is amplified, it is a voltage amplifier that common-mode feedback control signal produces circuit 102 herein, and input is voltage, the letter of output
Number it is also voltage signal, the common-mode feedback control signal produces circuit 102 and the voltage of output is connected to two-stage differential amplifier
Metal-oxide-semiconductor M105, M106 grid, by adjusting the grid voltage of metal-oxide-semiconductor M105, M106 stablizing the direct current of M105, M106
Operating point, and then the DC point of stable metal-oxide-semiconductor M107, M108, finally make the output common mode voltage (Vocm1) and the two-stage
The desired output common-mode voltage (Vcm1) of difference amplifier is equal.
The two-stage differential amplifier 100 of the existing common mode feedback circuit of employing shown in Fig. 1 is applied to into as shown in Figure 3 two
In the closed loop typical application circuit 300 of level difference amplifier.For differential signal, the loop of the application circuit 300 includes three
Inverter stages：The inverter stages that first order amplifier is formed, the inverter stages that second level amplifier is formed, amplifier output arrive input
Inverter stages (output end vo+be connected with input Vin-, output end vo-be connected with input Vin+), three inverter stages are constituted to be born
Feedback, as long as carrying out suitable frequency compensation to circuit, can just be operated in steady statue.For common-mode signal, the application circuit
300 loop includes two loops：Internal loop and external loop-around, wherein internal loop are a feedback loop, and outside
Loop is a regenerative feedback loop (see reference document 2)；During normal work, due to internal common mode feedback control loop open-loop gain very
It is high so that the open-loop gain of outside regenerative feedback loop is far smaller than 1, and whole circuit being capable of steady operation.And answer actual
With in, as shown in figure 1, when very big instantaneous value occurs in the input common-mode signal of two-stage differential amplifier, two-stage differential is put
M101, M102 pipe shut-off of big device, the electric current for flowing through M105, M106 pipe is 0, and M105, M106 pipe is operated in deep linear zone and (assumes
The common-mode voltage detection circuit 101 does not also produce the output that the transmission of circuit 102 is detected to the common-mode feedback control signal
Common-mode voltage), the drain terminal voltage of M105, M106 pipe is pulled to close to ground (0V), causes M107, M108 pipe to turn off, so that
The output common mode voltage of two-stage differential amplifier is close to supply voltage VDD, thus, M111 pipes are turned off, the grid electricity of M113 pipes
Pressure is pulled low, and then is turned off M105, M106 pipe, causes internal common mode feedback loop to disconnect so that outside positive feedback loop
The open-loop gain on road is more than 1, meets positive feedback condition, even if now common-mode signal is returned to normally, due to external loop-around
Positive feedback is formed, the output end voltage of two-stage differential amplifier will continue to remain close to the state of supply voltage, present " locked
" state makes the amplifier cannot normal work.
List of references 1：Jhin-Fang Huang,Yen-Jung Lin,Kun-Chieh Huang,Ron-Yi Liu.A
Continuous-Time Sigma-Delta Modulator with a Hybrid Loop Filter and
Capacitive Feedforward[J].Microelectronics and Solid State Electronics,2012,1
(4):74-80
List of references 2：Chi Baoyong. Analogous Integrated Electronic Circuits and system [M]. publishing house of Tsing-Hua University, Beijing, the 2009, the 8th
Chapter, pp:362.
The content of the invention
It is an object of the invention to overcome the deficiency of prior art, there is provided a kind of consecutive hours for two-stage differential amplifier
Between common mode feedback circuit, obtain difference voltage by the output common mode for detecting voltage and desired output common-mode voltage are subtracted each other,
Be converted to feedback current, and by the bias current one of the feedback current and common-mode feedback control signal generation unit described in the moment
Play the first order electricity of two-stage differential amplifier described in two output injections by the common-mode feedback control signal generation unit
Stream source loads, and the first order current source load for controlling the two-stage differential amplifier is stable in its default DC point, energy
Enough prevent two-stage differential amplifier in closed loop application when very big instantaneous value occurs in input common-mode signal, the two-stage differential is put
There is " locked " state in big device.
The technical solution adopted for the present invention to solve the technical problems is：A kind of consecutive hours for two-stage differential amplifier
Between common mode feedback circuit, including two-stage differential amplifier, for detecting the output common mode voltage of the two-stage differential amplifier
Common-mode voltage detector unit, and it is stable default at which for controlling the first order current source load of the two-stage differential amplifier
The common-mode feedback control signal generation unit of DC point；Two outputs of the two-stage differential amplifier connect described respectively
Common-mode voltage detector unit, the output of the common-mode voltage detector unit connect the common-mode feedback control signal generation unit,
Two of the common-mode feedback control signal generation unit export the first order electric current for connecting the two-stage differential amplifier respectively
Source loads；
The common-mode voltage detector unit detects the output common mode voltage of the two-stage differential amplifier, and the output is common
Mode voltage sends the common-mode feedback control signal generation unit to；The common-mode feedback control signal generation unit will be received
Output common mode voltage and desired output common-mode voltage subtract each other and obtain difference voltage, the difference voltage is converted to into feedback current,
And the feedback current is passed through into described together with the bias current of common-mode feedback control signal generation unit described in the moment respectively
The first order current source load of two-stage differential amplifier described in two output injections of common-mode feedback control signal generation unit, control
The first order current source load for making the two-stage differential amplifier is stable in its default DC point.
The common-mode feedback control signal generation unit includes the first common gate differential pair metal-oxide-semiconductor and bias current sources；Institute
Two metal-oxide-semiconductors for stating the first common gate differential pair metal-oxide-semiconductor are PMOS, two of the first common gate differential pair metal-oxide-semiconductor
Source electrode is connected and is connected to the output and the output of the common-mode voltage detector unit of the bias current sources；First common gate
Two grids of differential pair metal-oxide-semiconductor are all connected with a default reference voltage, and the reference voltage is equal to the desired output common mode
Voltage deduct the first common gate differential pair metal-oxide-semiconductor in its default DC point when gate source voltage；Described first
Two outputs of two drain electrodes of common gate differential pair metal-oxide-semiconductor respectively as the common-mode feedback control signal generation unit.
The bias current sources include first PMOS, and the source electrode of first PMOS connects the two-stage differential
The direct current power source voltage of amplifier, grid connect the first bias voltage, the output drained as the bias current sources；It is described common
The bias current of mould feedback control signal generation unit is the drain electrode output current of first PMOS.
The common-mode voltage detector unit includes the first resistor and second resistance of similar resistance, and the two-stage differential amplifies
Two outputs of device connect each of each one end of the first resistor and second resistance, the first resistor and second resistance respectively
The other end is connected and as the output of the common-mode voltage detector unit.
The first resistor and second resistance are also each parallel with the first electric capacity and the second electric capacity.
The two-stage differential amplifier also includes isolated location, and two of the common-mode feedback control signal generation unit are defeated
Go out and be connected by the isolated location between the first order current source load of the two-stage differential amplifier, the isolated location
Including the second common gate differential pair metal-oxide-semiconductor；Two source electrodes of the second common gate differential pair metal-oxide-semiconductor connect the common mode respectively
Two outputs of feedback control signal generation unit, and it is poor to connect the first order amplification input of the two-stage differential amplifier respectively
It is divided to two drain electrodes of to pipe two outputs, the second common gate differential pair metal-oxide-semiconductor to connect the first order current source respectively
Load, and the first order respectively as the two-stage differential amplifier amplifies output；The second common gate differential pair metal-oxide-semiconductor
Two grids are all connected with the second bias voltage.
The first order current source load of the two-stage differential amplifier includes a differential pair metal-oxide-semiconductor；The differential pair metal-oxide-semiconductor
Two grids be all connected with the 3rd bias voltage, two drain electrodes of the differential pair metal-oxide-semiconductor or two source electrodes are respectively as described
Two inputs of first order current source load, two source electrodes or two grounded drains of the differential pair metal-oxide-semiconductor.
From the above-mentioned description of this invention, compared with prior art, the present invention has the advantages that：
Compared with existing continuous time common-mode feedback, the present invention has two-stage differential amplifier in closed loop application
When very big instantaneous value occurs in input common-mode signal, prevent the two-stage differential amplifier from the advantage of " locked " state occur.
Description of the drawings
Fig. 1 is the two-stage differential amplifier schematic diagram using existing common mode feedback circuit；
Electrical block diagrams of the Fig. 2 for the embodiment of the present invention one；
Closed loop typical application circuit schematic diagrams of the Fig. 3 for two-stage differential amplifier；
Electrical block diagrams of the Fig. 4 for the embodiment of the present invention two.
Specific embodiment
Embodiment one,
As shown in Fig. 2 a kind of the invention provides continuous time common-mode feedback for two-stage differential amplifier
200, including two-stage differential amplifier, for detecting the output common mode voltage (being designated as Vocm2) of the two-stage differential amplifier
Common-mode voltage detector unit 201, and it is stable at which for controlling the first order current source load 203 of the two-stage differential amplifier
The common-mode feedback control signal generation unit 202 of default DC point；Two output (these of the two-stage differential amplifier
The voltage of two outputs in place is designated as Von2, Vop2 respectively) connect the common-mode voltage detector unit 201, the common mode electricity respectively
The output A2 of pressure detector unit 201 connects the common-mode feedback control signal generation unit 202, the common-mode feedback control signal
Two outputs B2, C2 of generation unit 202 connect the first order current source load 203 of the two-stage differential amplifier respectively；
The common-mode voltage detector unit 201 detect the two-stage differential amplifier output common mode voltage (Vocm2,
Vocm2=(Von2+Vop2)/2), and send the output common mode voltage (Vocm2) to the common-mode feedback control signal generation
Unit 202；The common-mode feedback control signal generation unit 202 will be the output common mode voltage (Vocm2) for receiving defeated with expectation
Go out common-mode voltage (being designated as Vcm2) and subtract each other to obtain difference voltage, the difference voltage is converted to into feedback current, and by feedback electricity
Stream (is the first PMOS described in the moment with the bias current of common-mode feedback control signal generation unit 202 described in the moment
The drain electrode output current of M213) together respectively by two outputs B2, C2 of the common-mode feedback control signal generation unit 202
The first order current source load 203 of the two-stage differential amplifier is injected, the first order electricity of the two-stage differential amplifier is controlled
Stream source load 203 is stable in its default DC point.
As one kind preferably, the common-mode feedback control signal generation unit 202 includes the first common gate differential pair metal-oxide-semiconductor
(M211, M212) and bias current sources；Two metal-oxide-semiconductors of the first common gate differential pair metal-oxide-semiconductor are PMOS, and described
Gate differential is connected to two source electrodes of metal-oxide-semiconductor and is connected to the output and common-mode voltage detection of the bias current sources altogether
The output A2 of unit 201；Two grids of the first common gate differential pair metal-oxide-semiconductor are all connected with a default reference voltage
Vref, the reference voltage Vref deduct the first common gate differential pair MOS equal to the desired output common-mode voltage (Vcm2)
Pipe is in gate source voltage during its default DC point, two drain electrode difference of the first common gate differential pair metal-oxide-semiconductor
As two outputs B2, C2 of the common-mode feedback control signal generation unit 202.
As one kind preferably, the bias current sources include first PMOS M213, first PMOS M213
Source electrode connect the direct current power source voltage VDD of the two-stage differential amplifier, grid to connect the first bias voltage (be described first
PMOS M213 provides suitable bias voltage), drain electrode as the bias current sources output.
As one kind preferably, the common-mode voltage detector unit 201 includes first resistor R201 and second of similar resistance
Resistance R202, two of two-stage differential amplifier output connect first resistor R201 and second resistance R202 respectively
Each other end of each one end, first resistor R201 and second resistance R202 is connected and as the common-mode voltage detector unit
201 output A2, then by first resistor R201 and second resistance R202, the common-mode voltage detector unit 201 can be detected
To Vocm2=(Von2+Vop2)/2.
As it is a kind of preferably, first resistor R201 and second resistance R202 be also each parallel with the first electric capacity C201 and
Second electric capacity C202.
As one kind preferably, the two-stage differential amplifier also includes isolated location, and the common-mode feedback control signal is produced
By described between two output B2, C2 of raw unit 202 and the first order current source load 203 of the two-stage differential amplifier
Isolated location connects, and the isolated location includes the second common gate differential pair metal-oxide-semiconductor (M203, M204)；Second common gate
Two source electrodes of differential pair metal-oxide-semiconductor connect two outputs B2, C2 of the common-mode feedback control signal generation unit 202 simultaneously respectively
The first order for connecting the two-stage differential amplifier respectively amplifies input difference to managing two outputs of (M201, M202), described
Two of second common gate differential pair metal-oxide-semiconductor drain electrodes connect the first order current source load 203 respectively, and respectively as described
The first order of two-stage differential amplifier amplifies output；Two grids of the second common gate differential pair metal-oxide-semiconductor are all connected with second
Bias voltage (provides suitable bias voltage for the second common gate differential pair metal-oxide-semiconductor).
The first order current source load 203 of the two-stage differential amplifier includes a differential pair metal-oxide-semiconductor (M205, M206)；
Two grids of the differential pair metal-oxide-semiconductor are all connected with the 3rd bias voltage and (provide suitable biased electrical for the differential pair metal-oxide-semiconductor
Pressure), two of differential pair metal-oxide-semiconductor drain electrodes or two source electrodes two respectively as the first order current source load 203
Input, two source electrodes or two grounded drains of the differential pair metal-oxide-semiconductor.In the present embodiment, M205, M206 pipe is NMOS
Pipe, therefore, two source grounds of M205, M206 pipe, two drain electrodes of M205, M206 pipe are negative as the first order current source
Two inputs of load 203 connect two of the common-mode feedback control signal generation unit 202 respectively by the isolated location
Output B2, C2.
When Vocm2 is less than Vcm2, the gate source voltage of PMOS M211, M212 reduces, and flows through the electric current of M211, M212 pipe
Reduce, the electric current of M203, M204, M205 and M206 pipe declines so that the two-stage differential amplifier first order amplifies output electricity
Pressure (drain voltage of M205, M206 pipe) step-down, so that in the grid voltage decline of M207, M208 pipe, output common mode voltage
Rise, finally make each transistor in Vocm2=Vcm2, and the two-stage differential amplifier return to respective default DC operation
Point；When Vocm2 is more than Vcm2, the electric current increase of M211, M212 pipe is flow through in the gate source voltage increase of M211, M212 pipe,
The electric current increase of M203, M204, M205 and M206 pipe so that the two-stage differential amplifier first order is amplified output voltage and become
Greatly, so that the grid voltage of M207, M208 pipe rises, output common mode voltage declines, and finally makes Vocm2=Vcm2, and institute
State each transistor in two-stage differential amplifier and return to respective default DC point, reach adjustment output common mode voltage
Purpose.
A kind of continuous time common-mode feedback 200 for two-stage differential amplifier of the embodiment of the present invention one is applied
In closed loop typical application circuit 300 as shown in Figure 3, then when the output that the common-mode voltage detector unit 201 is detected is total to
During mode voltage Vocm2=Vcm2, no electric current flow through first resistor R201, second resistance R202, the first electric capacity C201 and
Second electric capacity C202, now, it is assumed that the source-leakage current of first PMOS M213 is I213, metal-oxide-semiconductor M200 source-leakage current
For I200, metal-oxide-semiconductor M209 and M210 source-leakage current be I209, then flow through the first order amplification of the two-stage differential amplifier
Input difference is I to the source-leakage current of two PMOSs M201, M202 of pipe200/ 2, flow through PMOS M211 and M212
Source-leakage current is I213/ 2, the electric current for flowing through M203, M204, M205, M206 pipe is I200/2+I213/2.Therefore, only need root
According to these current datas, each metal-oxide-semiconductor of the design continuous time common-mode feedback 200 for two-stage differential amplifier
Breadth length ratio and bias voltage so that each MOS is operated in suitable DC point.
When very big instantaneous value occurs in the input common-mode signal of the two-stage differential amplifier, the first order is amplified
Input difference is turned off to two PMOSs M201, M202 of pipe, it is assumed that feedback circuit has not yet been formed (i.e. described common-mode voltage inspection
Survey the output common mode voltage that unit 201 is not also detected to the common-mode feedback control signal generation unit 202 transmission), then flow
The electric current of M203, M204, M205, M206 pipe is crossed by I200/2+I213/ 2 drop to I213/ 2, the drain terminal voltage quilt of M205, M206 pipe
Move to close to ground (0V), cause M207, M208 pipe shut-off of the second level amplifying circuit of the two-stage differential amplifier, it is described
The voltage Vop2 and Von2 of two outputs of two-stage differential amplifier is close to direct current power source voltage VDD.Now, common-mode voltage detection
Unit 201 detects output common mode voltage (Vocm2) close to VDD, and Vocm2 is input to the common-mode feedback control signal
The source of M211, M212 pipe of generation unit 202, and the grid voltage Vref of M211, M212 pipe is constant, therefore M211, M212
The difference voltage (Vocm2-Vcm2) that Vocm2 is more than Vcm2 is converted to feedback current by pipe, and (feedback current is substantially led to by VDD
Resistance capacitance branch road in crossing M209, M210 pipe and common-mode voltage detector unit 201 is provided, and is designated as 2 × I209') with the common mode
(now source-the leakage current of first PMOS M213, is designated as I to the bias current of feedback control signal generation unit 202213’)
Together respectively by two of the common-mode feedback control signal generation unit 202 output B2, C2 inject M203, M205 pipe and
M204, M206 are managed, and make M203, M204, M205, M206 pipe be operated in saturation region, so that whole internal common mode feedback circuit
Normal work, it is ensured that external common-mode loop gain is less than 1, is unsatisfactory for positive feedback condition, prevents " locked " state, and when defeated
When entering voltage and recovering normal, it is equal with the desired output common-mode voltage to enable to output common mode voltage, and makes the two-stage
Each transistor in difference amplifier returns to respective default DC point.
In sum, a kind of continuous time common-mode feedback for two-stage differential amplifier of the embodiment of the present invention one
200 when being applied in closed loop typical application circuit 300 as shown in Figure 3, is prevented from the input of two-stage differential amplifier altogether
When very big instantaneous value occurs in mould signal, there is " locked " state in the two-stage differential amplifier.
Embodiment two,
Fig. 4 is an alternative embodiment of the invention, the second common-mode voltage detector unit 401, the second common mode in the embodiment
Feedback control signal generation unit 402 respectively with embodiment one in common-mode voltage detector unit 201, common-mode feedback control signal
Generation unit 202 is identical, the two-stage differential amplifier architecture of the two-stage differential amplifier architecture in the embodiment and embodiment one
Difference, but operation principle is identical with embodiment one.
A kind of continuous time for two-stage differential amplifier that above-described embodiment is only used for further illustrating the present invention is common
Cmfb circuit, but embodiment is the invention is not limited in, every technical spirit according to the present invention is made to above example
Any simple modification, equivalent variations and modification, each fall within the protection domain of technical solution of the present invention.
Claims (5)
1. a kind of continuous time common-mode feedback for two-stage differential amplifier, it is characterised in that put including two-stage differential
Big device, for detecting the common-mode voltage detector unit of the output common mode voltage of the two-stage differential amplifier, and for controlling institute
State the stable common-mode feedback control signal in its default DC point of first order current source load of two-stage differential amplifier
Generation unit；Two outputs of the two-stage differential amplifier connect the common-mode voltage detector unit, the common mode electricity respectively
The output of pressure detector unit connects the common-mode feedback control signal generation unit, the common-mode feedback control signal generation unit
Two export and connect the first order current source load of the two-stage differential amplifier respectively；
The common-mode voltage detector unit detects the output common mode voltage of the two-stage differential amplifier, and the output common mode is electric
Pressure sends the common-mode feedback control signal generation unit to；The common-mode feedback control signal generation unit is defeated by what is received
Go out common-mode voltage and desired output common-mode voltage and subtract each other to obtain difference voltage, the difference voltage is converted to into feedback current, and will
The feedback current is together with the bias current of common-mode feedback control signal generation unit described in the moment respectively by the common mode
The first order current source load of two-stage differential amplifier described in two output injections of feedback control signal generation unit, controls institute
The first order current source load for stating two-stage differential amplifier is stable in its default DC point；
The common-mode feedback control signal generation unit includes the first common gate differential pair metal-oxide-semiconductor and bias current sources；Described
Gate differential is PMOS, two source electrodes of the first common gate differential pair metal-oxide-semiconductor to two metal-oxide-semiconductors of metal-oxide-semiconductor altogether
It is connected and is connected to the output and the output of the common-mode voltage detector unit of the bias current sources；The first common gate difference
One default reference voltage is all connected with to two grids of metal-oxide-semiconductor, the reference voltage is equal to the desired output common-mode voltage
Deduct the first common gate differential pair metal-oxide-semiconductor in its default DC point when gate source voltage；Described first common grid
Two outputs of two drain electrodes of pole differential pair metal-oxide-semiconductor respectively as the common-mode feedback control signal generation unit；
The common-mode voltage detector unit includes the first resistor and second resistance of similar resistance, the two-stage differential amplifier
Two outputs connect each another of each one end of the first resistor and second resistance, the first resistor and second resistance respectively
End is connected and as the output of the common-mode voltage detector unit.
2. a kind of continuous time common-mode feedback for two-stage differential amplifier as claimed in claim 1, its feature exist
In the bias current sources include first PMOS, and the source electrode of first PMOS connects the two-stage differential and amplifies
The direct current power source voltage of device, grid connect the first bias voltage, the output drained as the bias current sources；The common mode is anti-
The bias current of feedforward control signal generation unit is the drain electrode output current of first PMOS.
3. a kind of continuous time common-mode feedback for two-stage differential amplifier as claimed in claim 1, its feature exist
First electric capacity and the second electric capacity are parallel with also each in, the first resistor and second resistance.
4. a kind of continuous time common-mode feedback for two-stage differential amplifier as claimed in claim 1, its feature exist
Also include isolated location in, the two-stage differential amplifier, two outputs of the common-mode feedback control signal generation unit with
Connected by the isolated location between the first order current source load of the two-stage differential amplifier, the isolated location includes
Second common gate differential pair metal-oxide-semiconductor；Two source electrodes of the second common gate differential pair metal-oxide-semiconductor connect the common-mode feedback respectively
Two outputs of control signal generation unit, and connect the first order amplification input difference pair of the two-stage differential amplifier respectively
Two outputs of pipe, two drain electrodes of the second common gate differential pair metal-oxide-semiconductor connect the first order current source load respectively,
And the first order respectively as the two-stage differential amplifier amplifies output；Two of the second common gate differential pair metal-oxide-semiconductor
Grid is all connected with the second bias voltage.
5. a kind of continuous time common-mode feedback for two-stage differential amplifier as claimed in claim 1, its feature exist
In the first order current source load of the two-stage differential amplifier includes a differential pair metal-oxide-semiconductor；The two of the differential pair metal-oxide-semiconductor
Individual grid is all connected with the 3rd bias voltage, and two drain electrodes of the differential pair metal-oxide-semiconductor or two source electrodes are respectively as described first
Two inputs of level current source load, two source electrodes or two grounded drains of the differential pair metal-oxide-semiconductor.
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| CN108155882B (en) * | 2016-12-06 | 2021-04-20 | 瑞昱半导体股份有限公司 | Operational amplifier and differential amplification circuit thereof |
| JP6765125B2 (en) * | 2017-09-27 | 2020-10-07 | 日本電産リード株式会社 | Resistance measuring device, substrate inspection device, and resistance measuring method |
| CN107749709B (en) * | 2017-12-06 | 2023-07-07 | 西安智多晶微电子有限公司 | Charge pump for FPGA chip |
| CN109361365B (en) * | 2018-12-18 | 2023-10-13 | 天津三源兴泰微电子技术有限公司 | High-gain low-noise differential amplifier |
| CN114637717A (en) * | 2022-04-01 | 2022-06-17 | 苏州联讯仪器有限公司 | Detection circuit and differential receiver |
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| CN203840288U (en) * | 2014-05-05 | 2014-09-17 | 华侨大学 | Continuous time common mode feedback circuit for two-stage differential amplifier |
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| FR2562739B1 (en) * | 1984-04-06 | 1989-05-26 | Efcis | COMMON MODE DOUBLE FEEDBACK BROADBAND AMPLIFIER |
| JPH0514076A (en) * | 1991-07-04 | 1993-01-22 | Canon Inc | Differential amplifier device |
| EP0840442B1 (en) * | 1996-10-30 | 2003-01-29 | SGS-THOMSON MICROELECTRONICS S.r.l. | A two-stage fully differential operational amplifier with efficient common-mode feed back circuit |
| US6191622B1 (en) * | 1998-10-01 | 2001-02-20 | Ati International Srl | Time interleaved common mode feedback circuit with process compensated bias |
| CN103138691B (en) * | 2011-11-23 | 2016-04-13 | 上海华虹宏力半导体制造有限公司 | A kind of feedback operational amplifier |
-
2014
- 2014-05-05 CN CN201410185890.8A patent/CN103956982B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203840288U (en) * | 2014-05-05 | 2014-09-17 | 华侨大学 | Continuous time common mode feedback circuit for two-stage differential amplifier |
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