CN202334440U - Chopped wave amplification circuit and multistage amplification system - Google Patents
Chopped wave amplification circuit and multistage amplification system Download PDFInfo
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- CN202334440U CN202334440U CN2011204766454U CN201120476645U CN202334440U CN 202334440 U CN202334440 U CN 202334440U CN 2011204766454 U CN2011204766454 U CN 2011204766454U CN 201120476645 U CN201120476645 U CN 201120476645U CN 202334440 U CN202334440 U CN 202334440U
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- copped wave
- amplifying circuit
- amplifier
- chopper
- circuit
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Abstract
The utility model discloses a chopped wave amplification circuit and a multistage amplification system. The chopped wave amplification circuit comprises a first chopped wave amplifier controlled by a first chopped wave pulse, a second chopped wave amplifier which is connected in parallel with the first chopped wave amplifier and controlled by a second chopped wave pulse and a low-pass filter which is connected in series behind the first chopped wave amplifier and the second chopped wave amplifier, wherein when one of the two chopped wave amplifiers is switched, the other chopped wave amplifier works in a stable state, so that a peak caused by switching can be reduced effectively; and therefore, a typical value of offset voltage of the chopped wave amplification circuit can be reduced.
Description
[technical field]
The utility model relates to circuit design field, relates in particular to copped wave amplifying circuit and multistage amplification system.
[background technology]
Flourish along with Internet of Things, increasing product scope has been used transducer, and some signal of sensor is very little, and generally in the microvolt level, and the input of base amplifier imbalance is in the millivolt level.Therefore, base amplifier can not satisfy the amplification demand of the transducer of these small-signal outputs.
The existence of the input offset voltage of operational amplifier (Vos) will cause the error to input voltage, and finite gain (A0) will cause the error of the whole multiplication factor of amplifier.The Key Performance Indicator of instrument amplifier is high accuracy and low noise.This requires its built-in operational amplifier that adopts to have high voltage gain, low maladjustment voltage and low input equivalent noise.The source of the input equivalence offset voltage of operational amplifier is the mismatch of IC-components parameter; Typically bipolar (bipolar) technology can cause input offset voltage Vos about 0.1mV; And the imbalance that CMOS (Complementary Metal Oxide Semiconductor, complementary metal oxide semiconductors (CMOS)) technology causes is 10 times even 100 times of bipolar process.
Existing copped wave amplifying circuit can reduce input offset voltage.Fig. 1 shows a kind of typical copped wave amplifying circuit in the prior art.Said copped wave amplifying circuit comprises first chopper circuit 11, amplifier 1, second chopper circuit 12 and low-pass filter circuit (not shown).
Said first chopper circuit 11 comprises four switch element 11a, 11b, 11c and 11d; The conducting of copped wave pulse
control switch unit 11a and 11b and ending, the conducting of copped wave pulse
control switch unit 11c and 11d and ending.Said second chopper circuit 12 comprises four switch element 12a, 12b, 12c and 12d; The conducting of copped wave pulse
control switch unit 12a and 21b and ending, the conducting of copped wave pulse
control switch unit 12c and 12d and ending.Wherein, Copped wave pulse
and
are the square-wave signal that frequency is fc; Both phase phasic difference 180 degree, as shown in Figure 2.
Suppose that each switch element with said chopper circuit is set at conducting when high level, ends when low level.In conjunction with illustrated in figures 1 and 2; T1 constantly and t2 constantly between; Copped wave pulse
is a high level, and copped wave pulse
is a low level.Thereby, switch element 11a, 11b, 12a and 12b conducting.At this moment; The input 15 of first chopper circuit 11 links to each other with the positive input terminal of amplifier 1; The input 16 of first chopper circuit 11 links to each other with the negative input end of amplifier 1; The positive output end 30 of said amplifier 1 links to each other with the output 17 of second chopper circuit 12, and the negative output terminal 31 of said amplifier 1 links to each other with the output 18 of second chopper circuit 12.
T2 constantly and t3 constantly between; Copped wave pulse
is a low level, and copped wave pulse
is a high level.Thereby, switch element 11c, 11d, 12c and 12d conducting.At this moment; The input 15 of first chopper circuit 11 links to each other with the negative input end of amplifier 1; The input 16 of first chopper circuit 11 links to each other with the positive input terminal of amplifier 1; The positive output end 30 of said amplifier 1 links to each other with the output 18 of second chopper circuit 12, and the negative output terminal 31 of said amplifier 1 links to each other with the output 17 of second chopper circuit 12.
Noise and the frequecy characteristic of input signal at each part place of copped wave amplifying circuit shown in Figure 1 are described with reference to Fig. 3 A-3G below.The curve chart of Fig. 3 A-3F representes that respectively (longitudinal axis is an amplitude for the frequecy characteristic of each part; Trunnion axis is a frequency), Fig. 3 G is the sketch map of copped wave pulse
.In this case, said amplifier 1 has input noise described in Fig. 3 C and offset voltage Vn.
The input signal Vin of the frequency characteristic shown in Fig. 3 A is transfused to; At first chopper circuit, 11 places based on copped wave pulse
(because copped wave pulse
is the inversion signal of copped wave pulse
; Therefore two copped wave pulses can be regarded one in fact as) modulate, thus form modulation signal with the frequency characteristic shown in Fig. 3 B.Afterwards, in amplifier 1, input noise shown in Fig. 3 C and offset voltage Vn are added to and will from the modulation signal of said amplifier 1 output, obtain the amplifying signal shown in Fig. 3 D.Subsequently; Based on copped wave pulse
amplifying signal is carried out demodulation at second chopper circuit 12, obtain the output signal of the frequency characteristic shown in Fig. 3 E.At this moment, on the frequency of the odd of said chopper circuit 12 frequency that the input noise and the offset voltage Vn of amplifier 1 is modulated to said copped wave pulse
.Low pass filter 13 is used for the high fdrequency component of the signal of said second chopper circuit of filtering 12 outputs, thereby obtains to have the output signal of the frequecy characteristic shown in Fig. 3 F.
Can find out that typical copped wave amplifying circuit separates with useful signal noise through the modulation and demodulation process and adopts low pass filter will lack of proper care and noise filtering on frequency domain.Yet existing typical copped wave amplifying circuit still has the offset voltage about 10uV, this be since in the copped wave process switching signal signal path impacted formed spiking, this spiking has formed remaining imbalance after through low pass filter.In addition, the general gain of existing chopper amplifier is less, can not satisfy the needs that most of transducer small-signals amplify.
Therefore, be necessary to propose a kind of improved signal amplification scheme and overcome the problems referred to above.
[utility model content]
One of technical problem that the utility model will solve is to provide a kind of copped wave amplifying circuit, and it has less input offset voltage.
One of technical problem that the utility model will solve is to provide a kind of multistage amplification system, and it has the higher voltage gain.
In order to address the above problem, according to an aspect of the utility model, the utility model provides a kind of copped wave amplifying circuit, and it comprises: by pulse controlled first chopper amplifier of first copped wave; Parallelly connected with first chopper amplifier by pulse controlled second chopper amplifier of second copped wave; With the low pass filter that is connected on behind first chopper amplifier and second chopper amplifier.
Further, each chopper amplifier includes first chopper circuit, amplifier that is controlled by corresponding copped wave pulse and second chopper circuit that is controlled by corresponding copped wave pulse.
Further, the first copped wave pulse, phase phasic difference identical with the frequency of the second copped wave pulse, 30 degree are to 150 degree.Preferably, the first copped wave pulse is spent with the phasic difference mutually 90 of the second copped wave pulse.
In order to address the above problem; An aspect according to the utility model; The utility model proposes a kind of multistage amplifier circuit, and it comprises: by the first order amplifying circuit that the copped wave amplifying circuit forms, the second level amplifying circuit of connecting with first order amplifying circuit; Third level amplifying circuit of connecting and the feedforward amplifying circuit parallelly connected with first order amplifying circuit and second level amplifying circuit with second level amplifying circuit.Said copped wave amplifying circuit comprises: by pulse controlled first chopper amplifier of first copped wave; Parallelly connected with first chopper amplifier by pulse controlled second chopper amplifier of second copped wave; With the low pass filter that is connected on behind first chopper amplifier and second chopper amplifier.
Compared with prior art, the utility model adopts two chopper amplifiers, and another is operated in stable state in two chopper amplifiers when switch switches, can effectively reduce the spike that the switch switching causes like this.Like this, can reduce the representative value of the offset voltage of copped wave amplifying circuit.
In addition, through adopting Muller compensating circuit and feedforward compensation circuit, the high-gain that the multistage amplification system in the utility model had both realized has obtained more phase margin simultaneously again.
About other purposes of the utility model, characteristic and advantage will combine accompanying drawing in embodiment, to describe in detail below.
[description of drawings]
In conjunction with reference to accompanying drawing and ensuing detailed description, the utility model will be more readily understood, the structure member that wherein same Reference numeral is corresponding same, wherein:
Fig. 1 is the circuit diagram of a kind of typical copped wave amplifying circuit in the prior art;
Fig. 2 is the waveform sketch map of the copped wave pulse among Fig. 1;
Fig. 3 A to Fig. 3 G schematically shows noise and the frequecy characteristic of input signal at each part place of the copped wave amplifying circuit among Fig. 1;
Fig. 4 is the copped wave amplifying circuit structural representation in one embodiment in the utility model;
Fig. 5 is the waveform sketch map of two copped wave pulses of the copped wave amplifying circuit among Fig. 4;
Fig. 6 be in the utility model employing the structural representation of multistage amplification system of copped wave amplifying circuit shown in Figure 4;
Fig. 7 is the curve chart of the gain frequency response of existing single-stage and secondary amplification system and the curve chart of phase-frequency response; With
Fig. 8 is curve chart and the curve chart of phase-frequency response of the gain frequency response of the multistage amplification system in the utility model.
[embodiment]
For above-mentioned purpose, the feature and advantage that make the utility model can be more obviously understandable, the utility model is done further detailed explanation below in conjunction with accompanying drawing and embodiment.
Alleged here " embodiment " or " embodiment " are meant that special characteristic, structure or the characteristic relevant with said embodiment can be contained at least one implementation of the utility model at least.Different local in this manual " in one embodiment " that occur and nonessential all refer to same embodiment, must not be yet with other embodiment mutually exclusive separately or select embodiment.
The structural representation of a kind of improved copped wave amplifying circuit 400 that Fig. 4 provides for the utility model.As shown in Figure 4; Low pass filter 43 after said copped wave amplifying circuit 400 comprises first chopper amplifier 41 and second chopper amplifier 42 of parallel connection and is connected on said chopper amplifier 41 and 42; Wherein first chopper amplifier 41 carries out the copped wave amplification to input signal under the first copped wave pulse
control; Second chopper amplifier 42 carries out copped wave to input signal and amplifies under the second copped wave pulse
control; The second copped wave pulse
is identical with the frequency of the first copped wave pulse
; Phase phasic difference 30 degree are to 150 degree, and preferably both phase phasic differences 90 are spent.
Each chopper amplifier all includes first chopper circuit as shown in Figure 1, amplifier (or claiming operational amplifier) and second chopper circuit; First chopper circuit and second chopper circuit carry out switch control according to the copped wave pulse of place chopper amplifier, amplify to realize copped wave.LPF is carried out in the output of 43 pairs of two copped wave chopper amplifiers of low pass filter, with the input noise and the offset voltage of filtering high frequency.
In the utility model, adopt two chopper amplifiers, another is operated in stable state in two chopper amplifiers when switch switches, and can effectively reduce switch like this and switch the spike that causes.The existence of spike is because there is of short duration floating sky in the switch element input of operational amplifier in handoff procedure in the chopper circuit, and the floating sky of input can cause the uncertainty of the output of operational amplifier, thereby forms spike.In the utility model, use the copped wave pulse of two intersections to come input signal is carried out copped wave; And with two signal plus; Therefore the input end of the operational amplifier in any chopper amplifier is when floating dummy status; The input end of the operational amplifier in another chopper amplifier is in stable state, and nondeterministic statement appears in the internal node of the operational amplifier of therefore avoiding, greatly reduce the height of spike.Like this, the representative value of the offset voltage of the operational amplifier of copped wave amplifying circuit can be lowered to about 1uV, and equivalent input noise has only about 10nV, and improved like this copped wave amplifying circuit 400 can satisfy the needs that most of transducer small-signals amplify.
Yet the general gain of chopper amplifier is less separately, can not satisfy the needs that most of transducer small-signals amplify.For most of transducers, they need have the amplifying circuit of very high voltage gain, require more than the 120dB usually.Simple two-stage cmos operational amplifier is even adopt cascode (cascode amplifier) structure can only obtain 80 to 90dB voltage gain usually.Therefore, in one embodiment, can realize being approximately the voltage gain of 140dB through adopting the multi-stage cascade amplifying technique.The employing of multistage amplification makes and has introduced a plurality of limits in the amplification system, bring the deterioration of stability thus, so phase compensation is just extremely important.
First order pole amplification system phase shift maximum is 90 degree, does not have stability problem, referring to gain frequency response curve L1 shown in Figure 7 and phase-frequency response curve L2.And the secondary amplification system that does not add compensation possibly cause the instability of system near 180 degree easily in the phase shift of unit gain place, referring to gain frequency response curve L3 shown in Figure 7 and phase-frequency response curve L2.So separating two limits, the method that the secondary amplification system adopts Muller to make up the difference usually obtains the above phase margin of 60 degree.Yet; In order to obtain the voltage gain of 140dB; In the utility model, need to adopt the structure of three grades of amplifications, adopt this moment simple Muller compensation can't realize the above phase margin of 60 degree, therefore need to adopt Muller compensation and feedforward compensation to unite the scheme of use.
The utility model has further proposed a kind of multistage amplification system 600, and it can carry out multistage amplification to improve gain to input signal.As shown in Figure 6, said multistage amplification system 600 comprises successively first order amplifying circuit 61, second level amplifying circuit 62, third level amplifying circuit 63 and the feedforward amplifying circuit 64 parallelly connected with first order amplifying circuit 61 and second level amplifying circuit 62 of series connection.First order amplifying circuit 61 can adopt copped wave amplifying circuit 400 shown in Figure 4, can reduce the input noise and the offset voltage of multistage amplification system like this.First order amplifying circuit 61 has adopted the Muller compensating circuit with second level amplifying circuit 62.The gain frequency response curve of said multistage amplification system 600 and phase-frequency response curve can be found out it when obtaining high-gain referring to shown in Figure 8, also can obtain the above phase margin of 60 degree.
This shows that through adopting Muller compensating circuit and feedforward compensation circuit, the high-gain that said multistage amplification system had both realized has obtained the above phase margin of 60 degree simultaneously again.
Above-mentioned explanation has fully disclosed embodiment of the present invention.It is pointed out that any change that technical staff's specific embodiments of the invention of being familiar with this field is done does not all break away from the scope of claims of the present invention.Correspondingly, the scope of claim of the present invention also is not limited only to previous embodiment.
Claims (5)
1. copped wave amplifying circuit is characterized in that it comprises:
By pulse controlled first chopper amplifier of first copped wave;
Parallelly connected with first chopper amplifier by pulse controlled second chopper amplifier of second copped wave; With
Be connected on the low pass filter behind first chopper amplifier and second chopper amplifier.
2. copped wave amplifying circuit according to claim 1 is characterized in that, each chopper amplifier includes first chopper circuit, amplifier that is controlled by corresponding copped wave pulse and second chopper circuit that is controlled by corresponding copped wave pulse.
3. copped wave amplifying circuit according to claim 1 is characterized in that, the frequency of the first copped wave pulse and the second copped wave pulse is identical, phase phasic difference 30 degree are to 150 degree.
4. copped wave amplifying circuit according to claim 3 is characterized in that, the first copped wave pulse is spent with the phasic difference mutually 90 of the second copped wave pulse.
5. multistage amplifier circuit is characterized in that it comprises:
By the first order amplifying circuit that forms like the arbitrary described copped wave amplifying circuit of claim 1 to 4;
The second level amplifying circuit of connecting with first order amplifying circuit;
The third level amplifying circuit of connecting with second level amplifying circuit; With
The feedforward amplifying circuit parallelly connected with first order amplifying circuit and second level amplifying circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204766454U CN202334440U (en) | 2011-11-25 | 2011-11-25 | Chopped wave amplification circuit and multistage amplification system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204766454U CN202334440U (en) | 2011-11-25 | 2011-11-25 | Chopped wave amplification circuit and multistage amplification system |
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| Publication Number | Publication Date |
|---|---|
| CN202334440U true CN202334440U (en) | 2012-07-11 |
Family
ID=46446404
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011204766454U Expired - Lifetime CN202334440U (en) | 2011-11-25 | 2011-11-25 | Chopped wave amplification circuit and multistage amplification system |
Country Status (1)
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117713A (en) * | 2012-12-26 | 2013-05-22 | 清华大学深圳研究生院 | Chopping amplifier and method of lowering offset voltage of chopping amplifier |
| CN104601127A (en) * | 2013-10-31 | 2015-05-06 | 上海华虹集成电路有限责任公司 | Operational amplifier circuit and reference voltage generating circuit module |
| CN105099379A (en) * | 2014-05-09 | 2015-11-25 | 亚德诺半导体集团 | Amplifier input stage and amplifier |
| CN105680811A (en) * | 2016-01-05 | 2016-06-15 | 嘉兴禾润电子科技有限公司 | Amplifier with low power consumption, high gain and wide broadband |
| WO2017091998A1 (en) * | 2015-12-03 | 2017-06-08 | Abb Beijing Drive Systems Co., Ltd. | Chopper assembly and controlling method thereof |
| CN106940394A (en) * | 2017-04-24 | 2017-07-11 | 南京南瑞继保电气有限公司 | It is a kind of to realize the method that optical current mutual inductor is measured at a high speed |
| CN109212448A (en) * | 2018-08-22 | 2019-01-15 | 中国科学院地质与地球物理研究所 | Auto zeroing circuit |
-
2011
- 2011-11-25 CN CN2011204766454U patent/CN202334440U/en not_active Expired - Lifetime
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117713B (en) * | 2012-12-26 | 2015-08-19 | 清华大学深圳研究生院 | A kind of chopper amplifier and reduce the method for its offset voltage |
| CN103117713A (en) * | 2012-12-26 | 2013-05-22 | 清华大学深圳研究生院 | Chopping amplifier and method of lowering offset voltage of chopping amplifier |
| CN104601127A (en) * | 2013-10-31 | 2015-05-06 | 上海华虹集成电路有限责任公司 | Operational amplifier circuit and reference voltage generating circuit module |
| CN105099379A (en) * | 2014-05-09 | 2015-11-25 | 亚德诺半导体集团 | Amplifier input stage and amplifier |
| US10312794B2 (en) | 2015-12-03 | 2019-06-04 | Abb Beijing Drive Systems Co., Ltd. | Chopper assembly and controlling method thereof |
| WO2017091998A1 (en) * | 2015-12-03 | 2017-06-08 | Abb Beijing Drive Systems Co., Ltd. | Chopper assembly and controlling method thereof |
| CN108370217A (en) * | 2015-12-03 | 2018-08-03 | 北京Abb电气传动系统有限公司 | Copped wave device assembly and its control method |
| CN108370217B (en) * | 2015-12-03 | 2020-08-18 | 北京Abb电气传动系统有限公司 | Chopper assembly and control method thereof |
| CN105680811A (en) * | 2016-01-05 | 2016-06-15 | 嘉兴禾润电子科技有限公司 | Amplifier with low power consumption, high gain and wide broadband |
| CN105680811B (en) * | 2016-01-05 | 2018-05-25 | 嘉兴禾润电子科技有限公司 | A kind of high gain of low-power consumption and the amplifier architecture of wide bandwidth |
| CN106940394A (en) * | 2017-04-24 | 2017-07-11 | 南京南瑞继保电气有限公司 | It is a kind of to realize the method that optical current mutual inductor is measured at a high speed |
| CN109212448B (en) * | 2018-08-22 | 2020-06-16 | 中国科学院地质与地球物理研究所 | Self-stabilizing zero circuit |
| CN109212448A (en) * | 2018-08-22 | 2019-01-15 | 中国科学院地质与地球物理研究所 | Auto zeroing circuit |
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| CX01 | Expiry of patent term |
Granted publication date: 20120711 |
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| CX01 | Expiry of patent term |