CN203326960U - Accurate reference voltage generator in feedforward cancellation amplifier - Google Patents
Accurate reference voltage generator in feedforward cancellation amplifier Download PDFInfo
- Publication number
- CN203326960U CN203326960U CN2012207214633U CN201220721463U CN203326960U CN 203326960 U CN203326960 U CN 203326960U CN 2012207214633 U CN2012207214633 U CN 2012207214633U CN 201220721463 U CN201220721463 U CN 201220721463U CN 203326960 U CN203326960 U CN 203326960U
- Authority
- CN
- China
- Prior art keywords
- circuit
- triode
- reference voltage
- input
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000003990 capacitor Substances 0.000 claims description 29
- 230000008878 coupling Effects 0.000 claims description 20
- 238000010168 coupling process Methods 0.000 claims description 20
- 238000005859 coupling reaction Methods 0.000 claims description 20
- 230000004044 response Effects 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 5
- 238000007599 discharging Methods 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 10
- 230000006641 stabilisation Effects 0.000 description 8
- 238000011105 stabilization Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 230000010363 phase shift Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000013138 pruning Methods 0.000 description 1
Images
Landscapes
- Amplifiers (AREA)
Abstract
An accurate reference voltage generator in a feedforward cancellation amplifier is a reference voltage generator used for a differential amplifier. The reference voltage generator provides DC non-signal components in a reference voltage track difference input stage and provides a reference voltage to a level switch stage. Therefore, the feedforward reparation is used for providing broaden bandwidth and cannot cause problems on the aspect of settling time.
Description
Technical field:
The present invention relates to improve the integrated amplifier of performance, more particularly the present invention relates to improve the input stage of integrated amplifier, the bandwidth of amplifier and stability are improved.
Background technology:
The phase delay that the high performance integrated circuit operational amplifier is introduced in signal path by circuit element usually limits.For example, an important limiting factor is the frequency characteristic due to the bad luck of lateral PNP triode in signal path.In traditional multistage integrated operational amplifier, LM118 for example, the lateral PNP triode is for the differential to single-ended conversion stages between level conversion level and differential input stage and master gain level.The low frequency characteristic of lateral PNP triode is introduced a utmost point, and this is the open-loop transfer function of operational amplifier very.This limit system the entire gain frequency of amplifier, and the phase shift of introducing has reduced the stability of amplifier.
Reducing a kind of common method of this restriction on the PNP triode is to utilize feedforward compensation.The purpose of this type of compensation is to make feedforward capacitor walk around high-frequency level translator.Level translator is well suited for this process, because its output is a high impedance node.The use of feed-forward capacitance, for example, in the LM118 circuit of mentioning in front, in the high-frequency signal differential input stage, the output of homophase input is coupled to the Single-end output of level translator by feed-forward capacitance.
In addition, traditional feed-forward amplifier, as LM118, eliminate the high-frequency signal of half lentamente by lateral PNP, and this amplifier is the shunt capacitance of " single-ended ", and this shunt capacitance is coupled to the output of the anti-phase input of differential input stage.In conjunction with feedforward compensation, greatly extended the bandwidth of conventional operational amplifier.
Use above-mentioned shunt capacitor on traditional circuit, the shunting output of differential input stage offers level and shifts level, keeps the biasing balance of differential level transducer as a reference voltage source.As everyone knows, the difference input reference voltage that offers level translator is important, for the input off-set voltage of hold amplifier is as far as possible little, should follow the tracks of " DC component " of other difference input of level translator.In the application of identical common mode input amplifier (differential input end of supposing amplifier circuit is bundled in together) and in common mode input amplifier range of operation, " DC component " that voltage or electric current form will appear in the amplifier circuit of indication herein.When differential input signal is provided, curtage can further comprise one " signal component ".
Yet shunt capacitor has adverse influence to the performance of operational amplifier.Shunt capacitance forms a dipole at the open-loop response place of amplifier.The pole and zero of dipole is separated by grid, makes amplifier have the characteristic of poor adjustment time, and, after input changes, within certain extreme value scope, the shared time of the output of amplifier has improved.
Input stage at amplifier provides a new reference voltage generator, and the characteristic of traditional amplifier of feedforward compensation is improved.DC component in the output voltage of reference voltage tracking differential input stage, because do not have differential signal, so do not need shunt capacitor.This has eliminated the dipole of the amplifier transfer function produced from shunt capacitor.The amplifier improved provides the larger bandwidth without problem stabilization time.The applicant further recognizes the characteristic of other types integrated amplifier, as instrument amplifier can be improved by similar mode.
Another is the phase shift of being introduced to the current mirror circuit of single-ended signal conversion by difference to custom integrated circuit amplifier high frequency performance limitation.Current mirror circuit, to introduce a utmost point in amplifier, has weakened the stability of amplifier bandwidth.In the custom integrated circuit operational amplifier, do not reduce the impact that image current postpones.
In view of the foregoing, provide a reference voltage generator, follow the tracks of the DC component of differential input stage output, and provide a reference voltage to level translator, so that feedforward compensation can be used to provide a spread bandwidth without problem stabilization time.
Summary of the invention:
Reference voltage generator of the present invention is embodied in integrated circuit operational amplifier.In concrete embodiment, reference voltage generator comprises a NPN triode, a current source and a load resistance.The emitter of triode is connected to the positive pole of amplifier by current source and collector electrode by load resistance.The electric current produced by load resistance keeps transistor collector voltage.Therefore, a stable reference voltage does not need shunt capacitance to obtain.
Reference voltage generator is the base stage that the base stage by triode is coupled to corresponding triode in the differential input stage of a side, follows the trail of the DC component in the input stage output voltage.Further tracking can obtain with the voltage generator circuit of conventional design, layout and pruning technique the precision be complementary between reference voltage generator and differential input stage.
Reference voltage generator is followed the tracks of the no signal flip-flop of differential input stage output, and provides reference voltage for the second level of differential amplifier.In order to optimize its follow-up control, the element of reference voltage generator preferably and characteristic consistent with the respective element of a certain side of differential input stage mates.
Precise reference voltage generator in the feedforward compensation amplifier that the present invention proposes, an amplifier circuit comprises differential input stage and a second differnce input stage with input and output with output, the input that the lead-out terminal of this differential input stage is coupled to the second order input stage is brought in and is provided an input voltage without flip-flop to the second differnce input stage, reference voltage circuit comprises: at first, an input is connected to the input of differential input stage, produce a reference voltage at output, this reference voltage approximates greatly the input voltage without flip-flop, and provide it to first input end and second input of second differnce input stage.
Further, the second differnce input stage comprises that the level of an operation amplifier circuit shifts level; The first and second circuit of differential input stage are coupled to respectively the first and second inputs of differential input stage, the first and second circuit comprise a triode, current source is coupled to transistor emitter, current-voltage converter is coupling between the collector electrode and the first supply voltage of triode, differential input stage also comprises an emitter resistance, is coupling between the emitter of the emitter of the first circuit triode and second circuit triode; In reference voltage circuit, the base stage of a triode is coupled to first input of differential input stage, a current source is coupled to the emitter of triode, current-voltage converter is coupling between the collector electrode and supply voltage of triode, and the collector coupled of triode is to the output of reference voltage circuit; The current-voltage converter of reference voltage circuit comprises a resistor; In the first circuit of differential input stage, current-voltage converter has a resistance value, and a resistance equates substantially with the resistance value of the current-voltage converter of reference voltage circuit.
Further, the first and second inputs of differential input stage, comprise respectively homophase and the inverting input of amplifier.
Further, the base stage of reference voltage circuit triode is coupled to the base stage of the first circuit triode of differential input stage, thereby the collector voltage that causes the reference voltage circuit triode is followed the tracks of the fluctuation without flip-flop of voltage on the first circuit transistor collector, and common mode input is changed and responds; Follow the tracks of on the collector voltage of the first circuit triode fluctuation without flip-flop and be included in the fluctuation that the output impedance that limits in the first circuital current source produces.
Further, the first circuit of the current source of reference voltage and differential input stage all comprises a current source triode, and a resistively couple is between the emitter and second order supply voltage of current source triode; The base stage of the current source triode of reference voltage circuit and the first circuit of differential input stage are setovered by a common bias voltage.
Further, a differential transconductance input stage in the instrument amplifier circuit has a lead-out terminal, a differential transconductance feedback stage has a lead-out terminal, and its second level has first and second input terminal and lead-out terminal, first input end that the lead-out terminal of difference input and the lead-out terminal of feedback stage are coupled to respectively current-voltage converter and the second level is supplied an input voltage without flip-flop to the second level, reference voltage circuit comprises: at first, an input is connected to the input of a differential input stage, produce a reference voltage at output, this reference voltage approximates greatly the voltage of input without flip-flop, to offer the first input end of second differnce input stage, and for the second input of second differnce input stage provides a reference voltage, the second level in the instrument amplifier circuit comprises that a level shifts level, in the reference voltage circuit of instrument amplifier circuit, first order second order input is connected to an input of differential feedback level, differential input stage in the instrument amplifier circuit comprises the first and second circuit, the first and second circuit are coupled to respectively the first and second inputs of differential input stage, the first and second circuit comprise a triode and a current source that is coupled to the emitter of triode, wherein, current-voltage converter is coupling between the collector electrode and supply voltage of triode, the instrument amplifier circuit also comprises an emitter resistance, and emitter resistance is coupling between the emitter of the emitter of the first circuit triode and second circuit triode.
Further, a branch circuit of the reference voltage circuit in the instrument amplifier circuit comprises a triode, transistor base is coupled to first input of differential input stage, current source is coupled to the emitter of triode, current-voltage converter is coupling between the collector electrode and supply voltage of triode, and transistor collector is coupled to the output of reference voltage circuit; Differential transconductance feedback stage in the instrument amplifier circuit comprises the third and fourth circuit, and it is coupled to respectively reference and the feedback input end of differential feedback level, the third and fourth circuit comprises a triode and a current source that is coupled to transistor emitter, wherein, the current-voltage converter of differential input stage is coupling between the collector electrode and the first supply voltage of triode, the instrument amplifier circuit also comprises an emitter resistance, and emitter resistance is coupling between the emitter of the emitter of tertiary circuit triode and the 4th circuit triode; Reference voltage circuit in the instrument amplifier circuit also comprises another branch circuit, this branch circuit comprises a triode, the base stage of this triode is coupled to the reference input of differential feedback transconductance stage, a current source is coupled to the emitter of triode, current-voltage converter is coupled to the reference voltage circuit of the first branch circuit, this reference voltage circuit is coupling between the collector electrode and supply voltage of triode, and the collector coupled of triode is to the output of reference voltage circuit; In the reference voltage circuit of instrument amplifier circuit, the first and second branch circuit current-voltage converters comprise a common resistance.
Further, in instrument amplifier in the first circuit in the current-voltage converter of differential input stage and tertiary circuit the differential transconductance feedback stage comprise a resistor with similar resistance, and this resistance approximately equates with the resistance value of the current-voltage converter of the first and second branch circuits of reference voltage circuit, in the instrument amplifier circuit in first branch's reference voltage circuit the base stage of triode be coupled to the base stage of triode in the first circuit differential input stage, in the instrument amplifier circuit, the base stage of reference voltage circuit second branch's triode is coupled to the base stage of triode in tertiary circuit differential feedback transconductance stage, in the instrument amplifier circuit, in reference voltage circuit, the feedback stage of the first, second, third of the base stage of current source triode, differential transconductance input stage and the 4th circuit and differential transconductance is setovered by same bigoted voltage, in the instrument amplifier circuit, the first input end of differential input stage comprises the inverting input of an instrument amplifier, differential input stage in the instrument amplifier circuit comprises the first and second circuit, the first and second circuit are coupled to respectively forward and the reverse input end of instrument amplifier, the first and second circuit comprise a triode and are coupled to the current source of transistor emitter, the current source of the first circuit comprises a current source triode with collector-base capacitor and collector-substrate cpacity, the instrument amplifier circuit also comprises an electric capacity, this capacitive coupling is between the emitter of instrument amplifier in-phase input end and the first circuital current source triode, carry out On current, and the change in voltage to charging and discharging on the base stage-collector electrode of the first circuital current source triode and collector-substrate cpacity is made response.
Further, in integrated circuit, differential amplifier circuit comprises a differential input stage, a second level with first and second difference inputs, this second level receives the first and second voltage signals and is coupled to respectively the homophase of differential input stage and inverting input to drive the second level, connect outer member and realize amplifier circuit, and first and second inputs of the first and second drive voltage signal to the second level are provided, step comprises:
A, the first and second Difference Sets electrode currents that produce on differential input stage are made corresponding to the voltage on homophase and anti-phase integrated circuit;
B, provide the Difference Sets electrode current to produce a signal to corresponding current-voltage converter and without the first and second differential voltages of flip-flop;
C, provide the first differential voltage to the first input end of the second level as the first drive voltage signal, to produce a reference current, the voltage of integrated circuit in-phase input end is made to response;
D, provide reference current to produce the reference voltage without flip-flop that a size equals the second differential voltage substantially to current-voltage converter;
E, provide reference voltage to the input of the second order of the second level as the second order drive voltage signal.
The embodiment of reference voltage generator of the present invention also is described in the integrated circuit instrument amplifier.
Documents,
Patent of invention: the low-power consumption bandwidth multiplication operational amplifier that adopts the MOS device to realize, application number: 201110061084.6;
Patent of invention: high-bandwidth low-power consumption frequency-compensation three-stage operational amplifier, application number: 201010245853.3.
The accompanying drawing explanation:
According to the detailed description of following corresponding drawing, the above-mentioned advantage with other invention objects will be more obvious.The reference character of part of devices is indicated in the drawings.
The simplified block diagram of the conventional operation amplifier that Fig. 1 is a feedforward compensation circuit.
Fig. 2 is one and adopts the independently operational amplifier simplified block diagram of reference voltage source of feedforward compensation and, for the present invention is described in more detail.
The simplified block diagram that Fig. 3 is an operational amplifier, comprise reference voltage generator of the present invention and conventional level translator.
Fig. 4 is a simplified block diagram that adopts the conventional instrument amplifier of feedforward compensation.
The simplified block diagram that Fig. 5 is the reference voltage generator of the present invention in the instrument amplifier of Fig. 4.
Embodiment:
Fig. 1 has shown a simplified block diagram that adopts the conventional multi-stage operational amplifier 100 of feedforward compensation.Triode 101 and 102, resistor 105,108 and 109, current source 103 and 104 forms a conventional difference input stage 116.Triode 101 and 102 emitter link together by resistance 105, be the difference input voltage between the homophase input 116 and anti-phase input 107 of differential input stage 116, cause current direction resistance 105.This electric current is different from the collector current of triode 101 and 102.Collector electrode is connected to positive voltage by the load 108 and 109 with same resistance.Therefore, different collector currents causes differential output voltage having occurred between two collector electrodes.This difference voltage feeds back to the input of level translator 110.
Arrowband has seriously limited the bandwidth of operational amplifier.Therefore, when the Design enlargement device is used by very wide bandwidth, simple narrow-band compensation is unsafty.When realizing stability, improve to greatest extent bandwidth, except arrowband, often use feedforward compensation.Such compensation, the current source of not only removing high-frequency gain and phase shift also is removed.It is stable that arrowband is used to keep, and the frequency of gain but significantly increases, for example, by reducing the electric capacity of capacitor 111.
In Fig. 1, capacitor 114 has shown a typical conventional feedforward compensation scheme.High-frequency signal at the low frequency characteristic of level translator 110 PNP of place triode 110c and 110d by level translator is cancelled.The effect of capacitor 114 is the frequencies that increase dominant pole, thereby increases the gain bandwidth of amplifier.As previously mentioned, level translator 110 comprises a current mirror circuit 110b who realizes the conversion of differential to single-ended signal.
The differential to single-ended conversion of high frequency is realized by capacitor 115.This capacitor has been shunted the AC signal composition on triode 102 collector electrodes effectively, makes this signal be applied to an input y of level translator as reference voltage.The signal of triode 101 collector electrodes can be regarded as a single-ended signal that is applied to the second input x of level translator.
In order to reduce by the semaphore on triode 110d, the collector voltage of triode 102 should comprise the least possible AC signal.In traditional circuit, adopt large as far as possible shunt capacitor.Large capacitance obtains by the integrated capacitor 115 of the outer discrete capacitor of sheet often.Yet even it has a very large value, but the shortcoming of capacitor 115 has been to introduce zero limit in the open-loop transfer function to amplifier.
Fig. 2 has shown a theory diagram of the feedforward compensation amplifier 200 with a reference voltage generator circuit 200a, is intended to principle according to the present invention and meets the demands.The purpose of amplifier 200 is to introduce and illustrate the embodiment of first-selection of the present invention in Fig. 3.In amplifier 200, a stable reference voltage is supplied to level translator 110 from new voltage generator 200a, rather than provides from the collector electrode of triode 102. Current source 103 and 201 is identical basically, and load resistance 108 and 202 is also roughly the same.Therefore, ignore the defect of base current and current source, the stable reference voltage V at node 203 places
REFFollow the tracks of triode 101 collector voltage without flip-flop.Thereby no longer need the shunting signal on triode 102 collector electrodes, capacitor 115 can be removed.The reference voltage produced from an independent driven with current sources has been eliminated the open loop dipole, has also solved problem stabilization time.
Importantly, the DC component of reference voltage tracking report end signal.If these voltage differences, level conversion can be used for explaining the difference of the input signal amplified.The impact of this species diversity must remove by a non-zero voltage of the input of the input at amplifier.In operational amplifier, input offset voltage important parameter requirement is as much as possible little.Therefore, importantly reduce DC maladjustment as far as possible.
In practice, the shortcoming of Fig. 2 circuit is, it is unbalance that the voltage that offers the level conversion level can stop it to reduce to greatest extent direct current.At first, the collector current of triode 101 is less than its emitter current, and emitter current equals its base current.Secondly, due to the limited output impedance of current source 103, input common mode voltage causes that the collector current of triode 101 and 102 changes.These impacts can't make up Fig. 2 circuit.Therefore, in practice, voltage V
REFMay be with the collector voltage of triode 101 different without flip-flop.
In the simplified block diagram of the conventional operational amplifier 100 of the shortcoming of Fig. 2 circuit in Fig. 3 circuit, be eliminated.Operational amplifier 300 comprises the precise reference voltage generator 300a of an input stage 316, the DC component that input stage 316 is followed the tracks of triode 101 collector voltages.This circuit derives from Fig. 2, comprises triode 301.
In the circuit of Fig. 3, the base stage of triode 101 and 301 base stage link together.This can eliminate the shortcoming of Fig. 2 circuit.In the circuit of Fig. 3, triode 101 and 301 has identical base stage, emitter and collector electric current.In addition, suppose that corresponding circuit element take while mating accurately as first-selection, any common mode input signal can affect the output of current source 103 and 201.Therefore, the collector voltage of triode 301 is followed the tracks of the DC component of triode 101 collector voltages exactly.Yet, as sufficient explanation, from resistance 105 to triode, 101 collector voltage, the composition of the collector voltage of triode 301 is not followed fluctuation.
When the difference input is applied on terminal 106 and 107, because difference current flows through emitter resistance 105, the voltage signal composition appears on the collector electrode of triode 101.Do not have resistance to be connected to the emitter of triode 301, so do not have electric current to flow through collector electrode, there is no the voltage composition yet.Therefore, the collector electrode of triode 301 has identical value as a reference voltage source with the DC component of triode 101 collector voltages.This provides balanced input for level translator 110.
The follow-up control that offers the ideal reference signal of level translator 110 can realize by the operational amplifier of carrying out, and the element of difference part one side of the reference voltage generator circuit of integrated circuit and the input stage of Fig. 3 316 is basic identical.Certainly, it is different that the differential input stage in amplifier circuit is used from Fig. 3, and reference voltage generator can be set as identical specific input stage.
Clearly, reference voltage generator of the present invention can be used for various conventional difference level conversion levels.First-selection is in the integrated circuit of amplifier is implemented, the element of design and layout reference voltage generator circuit 300a, thus the temperature coefficient of reference voltage generator circuit 300a is matched in the difference equipment partly of corresponding input stage 316 1 sides accurately with other correlation properties.This can realize by design and the topology of the custom integrated circuit device with known.Outside adjusting zero resistor network, resistance adjustable network and input bias current compensation, all conventional arts that use of implementing, also can be used for further minimizing in DC maladjustment and the deviation mistake of input stage.
On the other hand, the follow-up control of reference voltage is can be received, and the few exact method of the present invention can be used.For example, use the resistance on current source and reference voltage generator circuit 300a, may produce a track reference voltage.But to the ratio of those input stage difference part, the direct voltage on triode 301 collector electrodes still can follow the tracks of triode 101 collector voltages without flip-flop.In addition, reference voltage generator circuit 300a can be used, so that it is connected to an anti-phase side rather than positive one side of the input stage 300a difference part shown in Fig. 3.
The accurate reference voltage generator of the present invention can, for various circuit, except the operation amplifier circuit shown in Fig. 1 to 3, and need a reference voltage to follow the tracks of the DC component of second voltage.An instrument amplifier that example is feedforward compensation discussed below.Instrument amplifier is designed to have very high common-mode rejection ratio, processes predetermined gain, and has higher input impedance in anti-phase and noninverting input.
The rough schematic view of the conventional instrument amplifier 400 that Fig. 4 is a feedforward compensation.This circuit comprises: two feedback load resistance 108 and 109 differential transconductance level 413 and 414; A voltage gain module 403 that comprises level conversion level 110, master gain level 112 and feedforward compensation network, the feedforward compensation network packet is containing capacitor 111 and 114; The feedback network that comprises in addition resistance 406 and 407.
Be applied to the difference input voltage of anti-phase 106 and homophase 107 inputs of transconductance stage 413, cause that difference current flows into load resistance 108 and 109, and cause node 401 different with the voltage at 402 places.Yet gain module 403 is connected on negative feedback loop, to be equilibrated at the voltage at node 401 and 402 places.This equation is that the differential voltage by node 404 and 405 equates substantially and node 106 and 107 s' polarity realizes on the contrary.This electric current that can cause flowing through triode 408 and 409 carrys out the electric current of balance triode 101 and 102, and the electric current that flows through resistance 108 and 109 is equated with it. Resistance 406 and 407 is set the gain of instrument amplifier.
The feedforward compensation instrument amplifier is operated under identical mode, and Fig. 1 is the operational amplifier that uses capacitor 111,114 and 115.Before this, capacitor 115 causes that a dipole appears at the transfer function place, and this has caused very long stabilization time.
In instrument amplifier 500 shown in Fig. 5, the feedforward reference voltage generator 500a of problem the application of the invention stabilization time is eliminated.In this circuit, the reference voltage of the level translator 110 in gain module 403 provides from reference voltage generator 500a rather than by the triode 102 of capacitor 115 parallel connections and 409 collector electrode.Therefore, capacitor 115 is eliminated the impact of amplifier transfer function, and causes that the dipole of very long stabilization time also is eliminated.
As shown in Figure 5, reference voltage generator 500a comprises the first circuit branch of the current source 201 that contains NPN triode 301 and connect with load resistance 202.In the operation amplifier circuit of Fig. 3, NPN triode 301 and current source 201 are designed to coordinate the respective element of difference transconductance stage 413.And for example shown in Fig. 3, three shown in can composition diagram 5 of current source 103,104 and 201 have 303,305 and 307, three of identical resistance that identical triode 302,304 and 306 is arranged, and they are by a common bias voltage V
BIASDrive.
Because load resistance 108 is controlled the collector current that triode 101 and 408 combines, load resistance 109 is controlled the collector current that triode 102 and 409 combines, in Fig. 3, load resistance 108 and 109 resistance value are reduced from the load resistance 108 and 109 of amplifier separately, this is desirable, produce same DC offset voltage on the resistance of Fig. 5, as at Fig. 3 circuit.For example, the DC power supply 103,104,410 and 411 of Fig. 5 has been designed to load current value, each is about as much as the value of Fig. 3 current source 103 and 104, then, in Fig. 5, load resistance 108 and 109 resistance value should be approximately Fig. 3 half of resistance value separately, obtain identical DC offset voltage.In addition, if reference voltage generator circuit 500a only includes above-mentioned the first branch that is connected to load resistance 202---the simple and useful enforcement of the present invention in instrument amplifier, the resistance value of load resistance 202 will be the twice of resistance 108 or 109, produce a reference voltage V
REFFollow the tracks of triode 101 and 408 collector voltages without flip-flop.
Yet the common-mode rejection ratio of integrated circuit instrument amplifier as shown in Figure 5 can provide by the reference voltage generator circuit 500a that is connected to additional circuit branch on transconductance stage 414.Extra circuit branch comprises NPN triode 502 and current source 504, the conduction current on identical triode 408 and current source 410 and load resistance 202.Current source 504,410 and 411 may form a large amount of identical circuit, each circuit comprises a triode (506,508 and 510) and an emitter resistance (507,509 and 511) and may drive (identical bias voltage V as shown in Figure 5, by a common bias voltage
BIASBe suitable for current source 201,103 and 104).Current source 504,410 may be different with 104 emitter resistances from current source 201,103 with 411, and the relative quantity of input transconductance stage 413 and feedback transconductance stage electric current is different.
The circuit branch of the circuit 500a of reference voltage generator of the present invention is connected to transconductance stage 413 and 414, as shown in Figure 5, the resistance value of load resistance 202 equals load resistance 108 and 109 substantially, because load resistance 202 conduction resistances 108 and 109 electric currents that combine.As the amplifier of Fig. 3, design and the topology of known custom integrated circuit device can be used to coalignment and temperature coefficient.Outside adjusting zero network can be inputted transconductance stage 413 for balance, and resistance adjustable network and bias current compensation also can be used for further reducing input and feed back DC maladjustment and the biasing mistake of transconductance stage.
As shown in Figure 5, the common-mode rejection ratio of instrument amplifier 500, the frequency for example, increased on the capacitor of the low capacity (0.75pF) be coupled between can triode 304 emitters in the current source 103 of the in-phase input end 106 of amplifier and input transconductance stage 413 is increased.This capacitor is a best integrating device, in triode 304, by conduction current, provide common mode inhibition to carry out charging and discharging to base stage-collector electrode and collector-substrate cpacity, the charging and discharging of electric capacity is as the response that input changes to high frequency common mode, can not produce great variation to the electric current of current source 103 conduction.If necessary, a similar capacitor also may be coupled between triode 302 emitters of terminal 106 and reference voltage circuit 500a.
Therefore, differential amplifier produces reference voltage.Reference voltage generator is accurately followed the tracks of the non-signal component of direct current of differential amplifier, and provides a single ended input voltage to level translator in conjunction with the output of differential input stage, like this can feedforward compensation and avoided using the shortcoming of shunt capacitor.Although expressed in the diagram the preferential implementation that element of the present invention connects, to this technology, had the personnel of certain understanding can find out that such connection not necessarily and under the condition without prejudice to spirit of the present invention can connect additional element.To correlation technique, have the personnel of deep understanding can find out that the present invention can utilize and different scheme described herein realizes, scheme described herein be only illustrative and do not have limitedly, this invention is only limited by claim thereafter.
Claims (9)
1. the precise reference voltage generator in a feedforward compensation amplifier, it is characterized in that: an amplifier circuit comprises differential input stage and a second differnce input stage with input and output with output, the input that the lead-out terminal of this differential input stage is coupled to the second order input stage is brought in and is provided an input voltage without flip-flop to the second differnce input stage, reference voltage circuit comprises: at first, an input is connected to the input of differential input stage, produce a reference voltage at output, this reference voltage approximates greatly the input voltage without flip-flop, and provide it to first input end and second input of second differnce input stage.
2. the precise reference voltage generator in feedforward compensation amplifier according to claim 1 is characterized in that: the second differnce input stage comprises that the level of an operation amplifier circuit shifts level; The first and second circuit of differential input stage are coupled to respectively the first and second inputs of differential input stage, the first and second circuit comprise a triode, current source is coupled to transistor emitter, current-voltage converter is coupling between the collector electrode and the first supply voltage of triode, differential input stage also comprises an emitter resistance, is coupling between the emitter of the emitter of the first circuit triode and second circuit triode; In reference voltage circuit, the base stage of a triode is coupled to first input of differential input stage, a current source is coupled to the emitter of triode, current-voltage converter is coupling between the collector electrode and supply voltage of triode, and the collector coupled of triode is to the output of reference voltage circuit; The current-voltage converter of reference voltage circuit comprises a resistor; In the first circuit of differential input stage, current-voltage converter has a resistance value, and a resistance equates substantially with the resistance value of the current-voltage converter of reference voltage circuit.
3. the precise reference voltage generator in feedforward compensation amplifier according to claim 2 is characterized in that: the first and second inputs of differential input stage comprise respectively homophase and the inverting input of amplifier.
4. the precise reference voltage generator in feedforward compensation amplifier according to claim 3, it is characterized in that: the base stage of reference voltage circuit triode is coupled to the base stage of the first circuit triode of differential input stage, thereby the collector voltage that causes the reference voltage circuit triode is followed the tracks of the fluctuation without flip-flop of voltage on the first circuit transistor collector, and common mode input is changed and responds; Follow the tracks of on the collector voltage of the first circuit triode fluctuation without flip-flop and be included in the fluctuation that the output impedance that limits in the first circuital current source produces.
5. the precise reference voltage generator in feedforward compensation amplifier according to claim 4, it is characterized in that: the first circuit of the current source of reference voltage and differential input stage all comprises a current source triode, and a resistively couple is between the emitter and second order supply voltage of current source triode; The base stage of the current source triode of reference voltage circuit and the first circuit of differential input stage are setovered by a common bias voltage.
6. the precise reference voltage generator in feedforward compensation amplifier according to claim 1, it is characterized in that: a differential transconductance input stage in the instrument amplifier circuit has a lead-out terminal, a differential transconductance feedback stage has a lead-out terminal, and its second level has first and second input terminal and lead-out terminal, first input end that the lead-out terminal of difference input and the lead-out terminal of feedback stage are coupled to respectively current-voltage converter and the second level is supplied an input voltage without flip-flop to the second level, reference voltage circuit comprises: at first, an input is connected to the input of a differential input stage, produce a reference voltage at output, this reference voltage approximates greatly the voltage of input without flip-flop, to offer the first input end of second differnce input stage, and for the second input of second differnce input stage provides a reference voltage, the second level in the instrument amplifier circuit comprises that a level shifts level, in the reference voltage circuit of instrument amplifier circuit, first order second order input is connected to an input of differential feedback level, differential input stage in the instrument amplifier circuit comprises the first and second circuit, the first and second circuit are coupled to respectively the first and second inputs of differential input stage, the first and second circuit comprise a triode and a current source that is coupled to the emitter of triode, wherein, current-voltage converter is coupling between the collector electrode and supply voltage of triode, the instrument amplifier circuit also comprises an emitter resistance, and emitter resistance is coupling between the emitter of the emitter of the first circuit triode and second circuit triode.
7. the precise reference voltage generator in feedforward compensation amplifier according to claim 6, it is characterized in that: a branch circuit of the reference voltage circuit in the instrument amplifier circuit comprises a triode, transistor base is coupled to first input of differential input stage, current source is coupled to the emitter of triode, current-voltage converter is coupling between the collector electrode and supply voltage of triode, and transistor collector is coupled to the output of reference voltage circuit; Differential transconductance feedback stage in the instrument amplifier circuit comprises the third and fourth circuit, and it is coupled to respectively reference and the feedback input end of differential feedback level, the third and fourth circuit comprises a triode and a current source that is coupled to transistor emitter, wherein, the current-voltage converter of differential input stage is coupling between the collector electrode and the first supply voltage of triode, the instrument amplifier circuit also comprises an emitter resistance, and emitter resistance is coupling between the emitter of the emitter of tertiary circuit triode and the 4th circuit triode; Reference voltage circuit in the instrument amplifier circuit also comprises another branch circuit, this branch circuit comprises a triode, the base stage of this triode is coupled to the reference input of differential feedback transconductance stage, a current source is coupled to the emitter of triode, current-voltage converter is coupled to the reference voltage circuit of the first branch circuit, this reference voltage circuit is coupling between the collector electrode and supply voltage of triode, and the collector coupled of triode is to the output of reference voltage circuit; In the reference voltage circuit of instrument amplifier circuit, the first and second branch circuit current-voltage converters comprise a common resistance.
8. the precise reference voltage generator in feedforward compensation amplifier according to claim 7, it is characterized in that: in instrument amplifier in the first circuit in the current-voltage converter of differential input stage and tertiary circuit the differential transconductance feedback stage comprise a resistor with similar resistance, and this resistance approximately equates with the resistance value of the current-voltage converter of the first and second branch circuits of reference voltage circuit, in the instrument amplifier circuit in first branch's reference voltage circuit the base stage of triode be coupled to the base stage of triode in the first circuit differential input stage, in the instrument amplifier circuit, the base stage of reference voltage circuit second branch's triode is coupled to the base stage of triode in tertiary circuit differential feedback transconductance stage, in the instrument amplifier circuit, in reference voltage circuit, the feedback stage of the first, second, third of the base stage of current source triode, differential transconductance input stage and the 4th circuit and differential transconductance is setovered by same bigoted voltage, in the instrument amplifier circuit, the first input end of differential input stage comprises the inverting input of an instrument amplifier, differential input stage in the instrument amplifier circuit comprises the first and second circuit, the first and second circuit are coupled to respectively forward and the reverse input end of instrument amplifier, the first and second circuit comprise a triode and are coupled to the current source of transistor emitter, the current source of the first circuit comprises a current source triode with collector-base capacitor and collector-substrate cpacity, the instrument amplifier circuit also comprises an electric capacity, this capacitive coupling is between the emitter of instrument amplifier in-phase input end and the first circuital current source triode, carry out On current, and the change in voltage to charging and discharging on the base stage-collector electrode of the first circuital current source triode and collector-substrate cpacity is made response.
9. the precise reference voltage generator in feedforward compensation amplifier according to claim 1, it is characterized in that: in amplifier circuit, differential amplifier circuit comprises a differential input stage, a second level with first and second difference inputs, this second level receives the first and second voltage signals and is coupled to respectively the homophase of differential input stage and inverting input to drive the second level, connect outer member and realize amplifier circuit, and first and second inputs of the first and second drive voltage signal to the second level are provided, and step comprises:
A, the first and second Difference Sets electrode currents that produce on differential input stage are made corresponding to the voltage on homophase and anti-phase integrated circuit;
B, provide the Difference Sets electrode current to produce a signal to corresponding current-voltage converter and without the first and second differential voltages of flip-flop;
C, provide the first differential voltage to the first input end of the second level as the first drive voltage signal, to produce a reference current, the voltage of integrated circuit in-phase input end is made to response;
D, provide reference current to produce the reference voltage without flip-flop that a size equals the second differential voltage substantially to current-voltage converter;
E, provide reference voltage to the input of the second order of the second level as the second order drive voltage signal.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012105678996A CN103117719A (en) | 2012-12-24 | 2012-12-24 | Precision reference voltage generator of feedforward compensation amplifier |
| CN2012207214633U CN203326960U (en) | 2012-12-24 | 2012-12-24 | Accurate reference voltage generator in feedforward cancellation amplifier |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012105678996A CN103117719A (en) | 2012-12-24 | 2012-12-24 | Precision reference voltage generator of feedforward compensation amplifier |
| CN2012207214633U CN203326960U (en) | 2012-12-24 | 2012-12-24 | Accurate reference voltage generator in feedforward cancellation amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203326960U true CN203326960U (en) | 2013-12-04 |
Family
ID=91334098
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012105678996A Pending CN103117719A (en) | 2012-12-24 | 2012-12-24 | Precision reference voltage generator of feedforward compensation amplifier |
| CN2012207214633U Expired - Fee Related CN203326960U (en) | 2012-12-24 | 2012-12-24 | Accurate reference voltage generator in feedforward cancellation amplifier |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012105678996A Pending CN103117719A (en) | 2012-12-24 | 2012-12-24 | Precision reference voltage generator of feedforward compensation amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (2) | CN103117719A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117719A (en) * | 2012-12-24 | 2013-05-22 | 苏州硅智源微电子有限公司 | Precision reference voltage generator of feedforward compensation amplifier |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104199501A (en) * | 2014-08-25 | 2014-12-10 | 长沙瑞达星微电子有限公司 | High-output impedance current source circuit |
| US9979350B2 (en) | 2014-11-17 | 2018-05-22 | Mediatek Inc. | Operational amplifier based circuit with compensation circuit block used for stability compensation |
| FR3055173B1 (en) * | 2016-08-22 | 2019-08-16 | Devialet | AMPLIFIER DEVICE COMPRISING A COMPENSATION CIRCUIT |
| CN106230432B (en) * | 2016-08-30 | 2023-04-28 | 成都紫微芯源科技有限公司 | High-speed signal level conversion circuit with low power consumption and ultra wide bandwidth |
| KR102661493B1 (en) * | 2018-11-05 | 2024-04-30 | 에스케이하이닉스 주식회사 | Signal receiving circuit, semiconductor apparatus and semiconductor system using the same |
| CN114115414B (en) * | 2022-01-27 | 2022-04-12 | 成都市安比科技有限公司 | Independent linear voltage stabilizing circuit without operational amplifier structure |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3562660A (en) * | 1967-12-26 | 1971-02-09 | Teledyne Inc | Operational amplifier |
| US4743862A (en) * | 1986-05-02 | 1988-05-10 | Anadigics, Inc. | JFET current mirror and voltage level shifting apparatus |
| US4767946A (en) * | 1987-01-12 | 1988-08-30 | Tektronix, Inc. | High-speed supply independent level shifter |
| US5148119A (en) * | 1991-03-22 | 1992-09-15 | Linear Technology Corporation | Precise reference voltage generator for feedforward compensated amplifiers |
| CN103117719A (en) * | 2012-12-24 | 2013-05-22 | 苏州硅智源微电子有限公司 | Precision reference voltage generator of feedforward compensation amplifier |
-
2012
- 2012-12-24 CN CN2012105678996A patent/CN103117719A/en active Pending
- 2012-12-24 CN CN2012207214633U patent/CN203326960U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117719A (en) * | 2012-12-24 | 2013-05-22 | 苏州硅智源微电子有限公司 | Precision reference voltage generator of feedforward compensation amplifier |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103117719A (en) | 2013-05-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN203326960U (en) | Accurate reference voltage generator in feedforward cancellation amplifier | |
| CN105393453B (en) | The device and method of transimpedance amplifier with wide input current range | |
| US7449958B1 (en) | Open loop DC control for a transimpedance feedback amplifier | |
| CN103856174B (en) | Circuit based on multimode operational amplifier | |
| US9467310B2 (en) | Wide common-mode range receiver | |
| US20120201260A1 (en) | Symmetrical, Direct Coupled Laser Drivers | |
| US8258867B2 (en) | Front-end equalizer and amplifier circuit | |
| CN204103873U (en) | A kind of active feed forward circuit forms frequency compensated differential operational amplifier | |
| US8963641B1 (en) | Source-series terminated differential line driver circuit | |
| CN104270107A (en) | Differential operational amplifier by using active feed-forward circuit for frequency compensation | |
| CN107505971A (en) | A kind of LDO adjuster frequency compensation schemes for driving large current load | |
| CN113507270B (en) | Variable gain amplifier | |
| Rincon-Mora et al. | A low voltage, rail-to-rail, class AB CMOS amplifier with high drive and low output impedance characteristics | |
| US7728669B2 (en) | Output stage circuit and operational amplifier thereof | |
| US5148119A (en) | Precise reference voltage generator for feedforward compensated amplifiers | |
| US6731165B1 (en) | Electronic amplifier | |
| CN103618509A (en) | Frequency compensation differential input amplifying circuit | |
| WO2011047159A1 (en) | High speed intra-pair de-skew circuit | |
| CN104320105B (en) | A kind of mixed mode capacity multiplier circuit | |
| US9860086B1 (en) | Equalizer circuit and optical module | |
| CN105897183B (en) | Have the function of to eliminate the circuit and amplifier of certainty noise | |
| Gupta et al. | Multipath common-mode feedback scheme suitable for high-frequency two-stage amplifiers | |
| US9608581B2 (en) | Differential amplifier | |
| US7538614B1 (en) | Differential amplifier with independent output common mode adjustment | |
| US7612609B1 (en) | Self-stabilizing differential load circuit with well controlled complex impedance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131204 Termination date: 20141224 |
|
| EXPY | Termination of patent right or utility model |