CN203914910U - A kind of Acquisition Circuit of high s/n ratio small-signal - Google Patents

Abstract

The applicable small-signal of this utility model gathers field, a kind of Acquisition Circuit of high s/n ratio small-signal is provided, comprise fully differential amplification module, both-end turns single-ended amplification module, low-pass filtering module, rear class amplification module, right lower limb driver module and electrode signal acquisition, the outfan of electrode signal acquisition connects the input of fully differential amplification module, the outfan of fully differential amplification module connects the input that both-end turns single-ended amplification module, both-end turns the input of the outfan connection low-pass filtering module of single-ended amplification module, the outfan of low-pass filtering module connects the input of rear class amplification module, acquired signal after the outfan output of rear class amplification module is processed, the test side of right lower limb driver module detect fully differential amplification module input collection small-signal common-mode voltage and through the outfan of right lower limb driver module, feed back to human body.Adopt high integrated high accuracy chip to realize high-pass filtering, remove polarizing voltage restriction, improve signal to noise ratio, reduction power consumption that small-signal gathers.

Description

A kind of Acquisition Circuit of high s/n ratio small-signal

Technical field

This utility model belongs to small-signal and gathers field, relates in particular to a kind of Acquisition Circuit of high s/n ratio small-signal.

Background technology

Mobile healthy, portable personal monitoring medical treatment is one of important component part in health care system after China.Can guard for a long time continuously individual, can find in time children under guardianship's the burst state of an illness or undesired physiological situation, by one of important need of medical and health services development after being.The real-time of this application and universality requirement, need a set of novel monitor system, must possess high accuracy, and miniaturization is integrated, the feature of low-power consumption.

The collection of some small-signals of human body at present, human ecg signal for example, EEG signals, mainly still adopts traditional instrument structure for amplifying, by building board-level circuit, realize, due to the existence of input signal direct current polarization pressure reduction, the amplification of instrument amplifier structure is limited, causes whole Acquisition Circuit signal to noise ratio restricted, take larger area simultaneously, in the armarium of all main flows, all adopt in this way, as shown in Figure 1 in the market; Occur in recent years this instrument structure for amplifying to carry out integrated chip, improve the integrated of circuit, as the AD8232 chip of Ya De promise semiconductor company (ADI) release, but the limited problem of the amplification of instrument structure for amplifying still exists.

There is following defect in the collection to small-signal of prior art:

(1) traditional acquisition mode of main flow is all to adopt instrument structure for amplifying on first order structure for amplifying at present, restriction due to polarizing voltage, therefore the gain amplifier of this grade of structure for amplifying must be less, in traditional implementation, this gain amplifier is generally 4 times to the maximum, otherwise can cause circuit saturated over the output voltage swing of circuit; And the little meeting of first order gain amplifier causes whole Acquisition Circuit structure noise smaller; Traditional acquisition mode is to build signal acquiring system by discrete element device simultaneously, consumes larger area and power consumption;

(2) existing minority chip, as the AD8232 of the ADS1298 of TI, Ya De promise quasiconductor (ADI), by IC regime, realize small-signal collection, but because the restriction of polarizing voltage causes the problem that the gain amplifier of first order structure for amplifying must be very little still to exist, signal to noise ratio is lower.

Utility model content

The purpose of this utility model is to overcome the deficiency that above-mentioned prior art exists, provide a kind of fully-differential amplifier of integrated high pass filter function to replace the instrument structure for amplifying in traditional electrocardiogram acquisition circuit, be applicable to solve the limited problem of amplification that causes amplifying circuit while gathering low frequency small-signal due to polarization pressure reduction, effectively improve the signal to noise ratio of whole Acquisition Circuit.

This utility model is to realize like this, a kind of Acquisition Circuit of high s/n ratio small-signal, described Acquisition Circuit comprises fully differential amplification module, both-end turns single-ended amplification module, low-pass filtering module, rear class amplification module, right lower limb driver module and electrode signal acquisition, the outfan of described electrode signal acquisition connects the input of described fully differential amplification module, the outfan of described fully differential amplification module connects the input that described both-end turns single-ended amplification module, the outfan that described both-end turns single-ended amplification module connects the input of described low-pass filtering module, the outfan of described low-pass filtering module connects the input of described rear class amplification module, electrocardiogram acquisition signal after the outfan output of described rear class amplification module is processed, the test side of described right lower limb driver module detect described fully differential amplification module input collection electrocardiosignal common-mode voltage and through the outfan of described right lower limb driver module, feed back to human body.

Further technical scheme of the present utility model is: described fully differential amplification module comprises the first filtration module, the second filtration module, ratio amplification module, the outfan of described the first filtration module connects the input of described ratio amplification module, the outfan of described the second filtration module connects the input of described proportional amplifier, the structure of described the first filtration module, the second filtration module is identical, it comprises little current biasing circuit and filter circuit, and the outfan of described little current biasing circuit connects the input of described filter circuit.

Further technical scheme of the present utility model is: described little current biasing circuit comprises current source Ibg, metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, metal-oxide-semiconductor M3, metal-oxide-semiconductor M4, metal-oxide-semiconductor MC1, metal-oxide-semiconductor MC2, metal-oxide-semiconductor MC3 and metal-oxide-semiconductor MC4, described current source Ibg one end connects respectively the drain electrode of described metal-oxide-semiconductor M1, the grid of grid and metal-oxide-semiconductor M2, described metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, the source electrode of metal-oxide-semiconductor M3 and metal-oxide-semiconductor M4 is connected, the grid of described metal-oxide-semiconductor M3, the grid of drain electrode and metal-oxide-semiconductor M4 connects respectively the drain electrode of described metal-oxide-semiconductor MC4, the source electrode of described metal-oxide-semiconductor MC4 connects the drain electrode of described metal-oxide-semiconductor MC3, the grid of described metal-oxide-semiconductor MC4 connects respectively the grid of described metal-oxide-semiconductor MC3 and the grid of metal-oxide-semiconductor MC2, the grid of described metal-oxide-semiconductor MC2, drain electrode connects respectively the drain electrode of described metal-oxide-semiconductor M2, the grid of described metal-oxide-semiconductor MC1, drain electrode connects respectively the drain electrode of described metal-oxide-semiconductor M2, described metal-oxide-semiconductor MC1, the source ground of metal-oxide-semiconductor MC2 and metal-oxide-semiconductor MC3, the other end ground connection of described current source Ibg.

Further technical scheme of the present utility model is: described filter circuit comprises metal-oxide-semiconductor MA, metal-oxide-semiconductor MB and capacitor C 2, the grid of the grid of described metal-oxide-semiconductor MA and metal-oxide-semiconductor MB, drain electrode connect respectively the drain electrode of described metal-oxide-semiconductor M4, the source electrode of described metal-oxide-semiconductor MA is connected with the source electrode of metal-oxide-semiconductor MB, and described capacitor C 2 is in parallel to source electrode with draining of described metal-oxide-semiconductor MA.

Further technical scheme of the present utility model is: described metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, metal-oxide-semiconductor M3, metal-oxide-semiconductor M4, metal-oxide-semiconductor MC1, metal-oxide-semiconductor MC2, metal-oxide-semiconductor MC3, metal-oxide-semiconductor MC4, metal-oxide-semiconductor MA and metal-oxide-semiconductor MB all adopt P-MOS.

Further technical scheme of the present utility model is: described ratio amplification module comprises the fully-differential amplifier OTA of both-end input both-end output, two capacitor C 1, two capacitor C 2, the positive input terminal of described fully-differential amplifier OTA connects one end of capacitor C 1 described in one of them, described in one of them, capacitor C 2 is in parallel to negative output terminal with the positive input terminal of described fully-differential amplifier OTA, the negative input end of described fully-differential amplifier OTA connects wherein one end of another capacitor C 1, wherein described in another, capacitor C 2 is in parallel to positive output end with the negative input end of described fully-differential amplifier OTA, described fully-differential amplifier OTA and four electric capacity form the amplification that electric capacity ratio amplifying circuit is realized gain A v.

Further technical scheme of the present utility model is: described both-end turns the amplifier A1 that single-ended amplification module comprises resistance R 1, resistance R 2, resistance R 3, resistance R 4 and the output of dual input list, the A end of described amplifier A1 connects one end of described resistance R 2, one end of described resistance R 1 connects respectively the B end of described resistance R 3 and amplifier A1, and described resistance R 4 is held to C end in parallel with the A of described amplifier A1.

Further technical scheme of the present utility model is: described low-pass filtering module comprises trsanscondutance amplifier Gm1, trsanscondutance amplifier Gm2, trsanscondutance amplifier Gm3, capacitor C 1 and capacitor C 2, one end of described capacitor C 1 connects respectively the C end of described trsanscondutance amplifier Gm1, the C end of trsanscondutance amplifier Gm2, the A end of described trsanscondutance amplifier Gm3 connects respectively the A end of described trsanscondutance amplifier Gm2 and the C end of trsanscondutance amplifier Gm1, and the B end of described trsanscondutance amplifier Gm3 holds with C the one end that is connected respectively described capacitor C 2; Or described low-pass filtering module comprises resistance R 11, resistance R 12, resistance R 13, resistance R 14, capacitor C 4, capacitor C 5 and amplifier A8, one end of described resistance R 11 connects respectively one end of described resistance R 12 and one end of capacitor C 5, the other end of described resistance R 12 connects respectively one end of capacitor C 4 and the A of amplifier A8 end, the other end of described capacitor C 5 connects the C end of described amplifier A8, the B end of described amplifier A8 is contact resistance R13 and resistance R 14 respectively, and the other end of described resistance R 14 connects the C end of described amplifier A8.

Further technical scheme of the present utility model is: described rear class amplification module comprises amplifier A2, resistance R 5 and resistance R 6, and the A end of described amplifier A2 connects one end of described resistance R 5, and the A of described amplifier A2 holds to C end in parallel with described resistance R 6.

Further technical scheme of the present utility model is: described right lower limb driver module comprises amplifier A3, amplifier A4, amplifier A5, amplifier A6, prime amplifier A7, resistance R 7, resistance R 8, resistance R 9, resistance R 10 resistance R _ f and capacitor C 3, after described resistance R 10 is in parallel with described resistance R _ f after connecting with described capacitor C 3, hold to C end in parallel with the A of described amplifier A6, the A end of described amplifier A6 also connects one end of described resistance R 7, the other end of described resistance R 7 connects respectively C end and the B end of described amplifier A5, the A end of described amplifier A5 connects respectively one end of described resistance R 8 and resistance R 9, the A end of described prime amplifier A7 connects respectively the other end of described resistance R 8 and the B of amplifier A3 end and C end, the B end of described prime amplifier A7 connects respectively the other end of described resistance R 9 and the B of amplifier A4 end and C end.

The beneficial effects of the utility model are: adopt the integrated fully-differential amplifier chip of high accuracy to replace the structure that traditional instrument is built formation, signal acquisition circuit Highgrade integration, miniaturization are improved, dwindled the overall volume of instrument; Pre-amplification module adopts the electric capacity structure for amplifying of more accurate ratio, realizes higher common mode rejection ratio; Adopt high integrated high accuracy chip to realize high-pass filtering, remove the restriction of polarizing voltage, improve signal to noise ratio, lowering apparatus equipment power dissipation that small-signal gathers.

Accompanying drawing explanation

Fig. 1 is traditional electrocardiogram acquisition circuit principle structure figure;

Fig. 2 is the small-signal Acquisition Circuit principle assumption diagram of the high s/n ratio that provides of this utility model embodiment;

Fig. 3 is the fully differential amplification module principle assumption diagram of the integrated high pass filter function that provides of this utility model embodiment;

Fig. 4 is that the both-end output that this utility model embodiment provides turns single-end circuit theory diagram;

Fig. 5 is the low-pass filter circuit principle assumption diagram that this utility model embodiment provides;

Fig. 6 is the rear class amplification module principle assumption diagram that this utility model embodiment provides;

Fig. 7 is the right lower limb driver module principle assumption diagram that this utility model embodiment provides;

Fig. 8 is the amplitude-frequency response figure that this utility model embodiment provides;

Fig. 9 be this utility model embodiment provide be input as sine time transient response;

Figure 10 is the Butterworth structure second order active low-pass filter structure chart that this utility model embodiment provides;

Figure 11 is the little current circuit structure chart of biasing that this utility model embodiment provides.

The specific embodiment

Reference numeral: 10-fully differential amplification module 20-both-end turns the right lower limb driver module of single-ended amplification module 30-low-pass filtering module 40-rear class amplification module 50-60-electrode signal acquisition

Fig. 2 shows the Acquisition Circuit of the high s/n ratio small-signal that this utility model provides, described Acquisition Circuit comprises fully differential amplification module 10, both-end turns single-ended amplification module 20, low-pass filtering module 30, rear class amplification module 40, right lower limb driver module 50 and electrode signal acquisition 60, the outfan of described electrode signal acquisition 60 connects the input of described fully differential amplification module 10, the outfan of described fully differential amplification module 10 connects the input that described both-end turns single-ended amplification module 20, the outfan that described both-end turns single-ended amplification module 20 connects the input of described low-pass filtering module 30, the outfan of described low-pass filtering module 30 connects the input of described rear class amplification module 40, electrocardiogram acquisition signal after the outfan output of described rear class amplification module 40 is processed, the test side of described right lower limb driver module 50 detect described fully differential amplification module 10 input collection electrocardiosignal common-mode voltage and through the outfan of described right lower limb driver module 50, feed back to human body.Electrode signal acquisition 60 acquired signal transmission enter fully differential amplification module 10, and the high-pass filtering of carrying out ultralow cut-off frequency when 10 pairs of signals of fully differential amplification module amplify can; After the signal after fully differential amplification module 10 is processed turns single-ended amplification module by both-end, be converted to Single-end output signal and export to low-pass filtering module; Signal after low-pass filtering module 30 secondary filterings enters after 40 pairs of signals of rear class amplification module further amplify and exports; The signal that 10 two inputs of 50 pairs of fully differential amplification modules of right lower limb driver module collect detects common-mode voltage and feeds back to human body, reduces the common mode disturbances of integrated circuit.Adopt the integrated fully-differential amplifier chip of high accuracy to replace the structure that traditional instrument is built formation, signal acquisition circuit Highgrade integration, miniaturization are improved, dwindled the overall volume of instrument; Pre-amplification module adopts the electric capacity structure for amplifying of more accurate ratio, realizes higher common mode rejection ratio; Adopt high integrated high accuracy chip to realize high-pass filtering, remove the restriction of polarizing voltage, improve signal to noise ratio, lowering apparatus equipment power dissipation that small-signal gathers.

As shown in Figure 3, described fully differential amplification module 10 comprises the first filtration module, the second filtration module, ratio amplification module, the outfan of described the first filtration module connects the input of described ratio amplification module, the outfan of described the second filtration module connects the input of described proportional amplifier, the structure of described the first filtration module, the second filtration module is identical, it comprises little current biasing circuit and filter circuit, and the outfan of described little current biasing circuit connects the input of described filter circuit.

Fully differential amplification module is by high-gain, low-power consumption, the fully differential trsanscondutance amplifier (0TA:operational transconductanceamplifier) of low noise both-end input both-end output, electric capacity, little current biasing circuit forms, and whole circuit has symmetry structure.The transfer function of this amplifying circuit is suc as formula (1):

$\frac{(\mathrm{VO}+)-(\mathrm{VO}-)}{(\mathrm{VIN}+)(\mathrm{VIN}-)}=\frac{C1}{C2}\×\frac{1}{1+\frac{\mathrm{IB}}{\mathrm{\Δ}{V}_{C2}\×C2\×s}}---\left(1\right)$

OTA and four electric capacity form electric capacity ratio amplifying circuit, realize gain enlarging function, simultaneously jointly realize cut-off frequency with the virtual resistance being connected across on amplifier $f_{\mathrm{hp}}=\frac{\mathrm{IB}}{2\mathrm{\π}*{\mathrm{\ΔV}}_{C2}*C2}$ High-pass filtering characteristic.

The both-end that the signal of fully differential amplifying circuit both-end output forms via amplifier and large resistance again turns single-end circuit, and output single-ended signal is to filter circuit module, as shown in Figure 4.R ₁=R ₂; R ₃=R ₄, when changing into single-ended signal, play gain an amplification.

Through the first order signal after doubly amplifying enters filter circuit, second-order low-pass filter as shown in Figure 6, and the second-order low-pass filter that low-pass filtering module is comprised of trsanscondutance amplifier Gm and capacitor C, its transfer function is suc as formula (2):

$\frac{V_{\mathrm{out}}}{V_{\mathrm{in}}}=\frac{G_m^2}{(G_m+\mathrm{sC}1)*(G_m+\mathrm{sC}2)}---\left(2\right)$

Realize cut-off frequency (C ₁=C ₂) low-pass filtering, G wherein _mit is the equivalent transconductance of trsanscondutance amplifier.

Filtered signal enters rear class amplification module and does second level amplification, and as shown in Figure 7, rear class amplifying circuit consists of amplifier and proportion resistor, realizes doubly amplify.Finally, through output buffer, send the output signal after amplification.

Power frequency is the main common mode disturbances of electrocardiosignal, only depends on amplifier that common mode rejection ratio is high can not eliminate the common-mode noise of input completely, so ecg signal acquiring circuit often adopts driven-right-leg circuit to suppress power frequency to disturb.The signal detection common-mode voltage that driven-right-leg circuit module collects input buffer also feeds back to human body, reduces the common mode disturbances of integrated circuit.As shown in Figure 8, the human body common-mode voltage VCM detecting enters amplifier A4 after amplifier A3 buffering, and the current i d by human body flows into the earth, but flows to A4.Right lower limb drives last output suc as formula (3):

$V_{\mathrm{cm}}=\frac{\mathrm{VCM}}{1+R_f/R_1}---\left(3\right)$

From (3) formula, increase the gain R of A4 _f/ R ₁can reduce human body common-mode voltage Vcm.Amplifier A1 wherein, A2, A3, what A4 adopted is all unity gain amplifier.

As shown in figure 11, state little current biasing circuit and comprise current source Ibg, metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, metal-oxide-semiconductor M3, metal-oxide-semiconductor M4, metal-oxide-semiconductor MC1, metal-oxide-semiconductor MC2, metal-oxide-semiconductor MC3 and metal-oxide-semiconductor MC4, described current source Ibg one end connects respectively the drain electrode of described metal-oxide-semiconductor M1, the grid of grid and metal-oxide-semiconductor M2, described metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, the source electrode of metal-oxide-semiconductor M3 and metal-oxide-semiconductor M4 is connected, the grid of described metal-oxide-semiconductor M3, the grid of drain electrode and metal-oxide-semiconductor M4 connects respectively the drain electrode of described metal-oxide-semiconductor MC4, the source electrode of described metal-oxide-semiconductor MC4 connects the drain electrode of described metal-oxide-semiconductor MC3, the grid of described metal-oxide-semiconductor MC4 connects respectively the grid of described metal-oxide-semiconductor MC3 and the grid of metal-oxide-semiconductor MC2, the grid of described metal-oxide-semiconductor MC2, drain electrode connects respectively the drain electrode of described metal-oxide-semiconductor M2, the grid of described metal-oxide-semiconductor MC1, drain electrode connects respectively the drain electrode of described metal-oxide-semiconductor M2, described metal-oxide-semiconductor MC1, the source ground of metal-oxide-semiconductor MC2 and metal-oxide-semiconductor MC3, the other end ground connection of described current source Ibg.

Described filter circuit comprises metal-oxide-semiconductor MA, metal-oxide-semiconductor MB and capacitor C 2, the grid of the grid of described metal-oxide-semiconductor MA and metal-oxide-semiconductor MB, drain electrode connect respectively the drain electrode of described metal-oxide-semiconductor M4, the source electrode of described metal-oxide-semiconductor MA is connected with the source electrode of metal-oxide-semiconductor MB, and described capacitor C 2 is in parallel to source electrode with draining of described metal-oxide-semiconductor MA.

Described metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, metal-oxide-semiconductor M3, metal-oxide-semiconductor M4, metal-oxide-semiconductor MC1, metal-oxide-semiconductor MC2, metal-oxide-semiconductor MC3, metal-oxide-semiconductor MC4, metal-oxide-semiconductor MA and metal-oxide-semiconductor MB all adopt P-MOS.

Described ratio amplification module comprises the fully-differential amplifier OTA of both-end input both-end output, two capacitor C 1, two capacitor C 2, the positive input terminal of described fully-differential amplifier OTA connects one end of capacitor C 1 described in one of them, described in one of them, capacitor C 2 is in parallel to negative output terminal with the positive input terminal of described fully-differential amplifier OTA, the negative input end of described fully-differential amplifier OTA connects wherein one end of another capacitor C 1, wherein described in another, capacitor C 2 is in parallel to positive output end with the negative input end of described fully-differential amplifier OTA, described fully-differential amplifier OTA and four electric capacity form the amplification that electric capacity ratio amplifying circuit is realized gain A v.

As shown in Figure 4, described both-end turns the amplifier A1 that single-ended amplification module 20 comprises resistance R 1, resistance R 2, resistance R 3, resistance R 4 and the output of dual input list, the A end of described amplifier A1 connects one end of described resistance R 2, one end of described resistance R 1 connects respectively the B end of described resistance R 3 and amplifier A1, and described resistance R 4 is held to C end in parallel with the A of described amplifier A1.

As shown in Fig. 5,10, described low-pass filtering module 30 comprises trsanscondutance amplifier Gm1, trsanscondutance amplifier Gm2, trsanscondutance amplifier Gm3, capacitor C 1 and capacitor C 2, one end of described capacitor C 1 connects respectively the C end of described trsanscondutance amplifier Gm1, the C end of trsanscondutance amplifier Gm2, the A end of described trsanscondutance amplifier Gm3 connects respectively the A end of described trsanscondutance amplifier Gm2 and the C end of trsanscondutance amplifier Gm1, and the B end of described trsanscondutance amplifier Gm3 holds with C the one end that is connected respectively described capacitor C 2; Or described low-pass filtering module comprises resistance R 11, resistance R 12, resistance R 13, resistance R 14, capacitor C 4, capacitor C 5 and amplifier A8, one end of described resistance R 11 connects respectively one end of described resistance R 12 and one end of capacitor C 5, the other end of described resistance R 12 connects respectively one end of capacitor C 4 and the A of amplifier A8 end, the other end of described capacitor C 5 connects the C end of described amplifier A8, the B end of described amplifier A8 is contact resistance R13 and resistance R 14 respectively, and the other end of described resistance R 14 connects the C end of described amplifier A8.

As shown in Figure 6, described rear class amplification module 40 comprises amplifier A2, resistance R 5 and resistance R 6, and the A end of described amplifier A2 connects one end of described resistance R 5, and the A of described amplifier A2 holds to C end in parallel with described resistance R 6.

As shown in Figure 7, described right lower limb driver module 50 comprises amplifier A3, amplifier A4, amplifier A5, amplifier A6, prime amplifier A7, resistance R 7, resistance R 8, resistance R 9, resistance R 10 resistance R _ f and capacitor C 3, after described resistance R 10 is in parallel with described resistance R _ f after connecting with described capacitor C 3, hold to C end in parallel with the A of described amplifier A6, the A end of described amplifier A6 also connects one end of described resistance R 7, the other end of described resistance R 7 connects respectively C end and the B end of described amplifier A5, the A end of described amplifier A5 connects respectively one end of described resistance R 8 and resistance R 9, the A end of described prime amplifier A7 connects respectively the other end of described resistance R 8 and the B of amplifier A3 end and C end, the B end of described prime amplifier A7 connects respectively the other end of described resistance R 9 and the B of amplifier A4 end and C end.

By Cadence Spectre instrument, adopting SMIC0.18 μ m technique to carry out post-simulation, as shown in Figure 8, is the amplitude-frequency response curve of system, and the AC characteristic Simulation result from each key point signal of main signal, conforms to design.As shown in Figure 9, be the Transient Performance Simulation result of system, output signal when input range is 3mV sinusoidal signal, sees that from Transient Performance Simulation result chip can normally work well, has realized and signal having been amplified and the filtering to out-of-band noise.

The foregoing is only preferred embodiment of the present utility model; not in order to limit this utility model; all any modifications of doing within spirit of the present utility model and principle, be equal to and replace and improvement etc., within all should being included in protection domain of the present utility model.

Claims (10)

1. the Acquisition Circuit of a high s/n ratio small-signal, it is characterized in that, described Acquisition Circuit comprises fully differential amplification module, both-end turns single-ended amplification module, low-pass filtering module, rear class amplification module, right lower limb driver module and electrode signal acquisition, the outfan of described electrode signal acquisition connects the input of described fully differential amplification module, the outfan of described fully differential amplification module connects the input that described both-end turns single-ended amplification module, the outfan that described both-end turns single-ended amplification module connects the input of described low-pass filtering module, the outfan of described low-pass filtering module connects the input of described rear class amplification module, electrocardiogram acquisition signal after the outfan output of described rear class amplification module is processed, the test side of described right lower limb driver module detect described fully differential amplification module input collection electrocardiosignal common-mode voltage and through the outfan of described right lower limb driver module, feed back to human body.

2. Acquisition Circuit according to claim 1, it is characterized in that, described fully differential amplification module comprises the first filtration module, the second filtration module, ratio amplification module, the outfan of described the first filtration module connects the input of described ratio amplification module, the outfan of described the second filtration module connects the input of described proportional amplifier, described the first filtration module, the second filtering modular structure are identical, it comprises little current biasing circuit and filter circuit, and the outfan of described little current biasing circuit connects the input of described filter circuit.

3. Acquisition Circuit according to claim 2, is characterized in that, described little current biasing circuit comprises current source Ibg, metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, metal-oxide-semiconductor M3, metal-oxide-semiconductor M4, metal-oxide-semiconductor MC1, metal-oxide-semiconductor MC2, metal-oxide-semiconductor MC3 and metal-oxide-semiconductor MC4, described current source Ibg one end connects respectively the drain electrode of described metal-oxide-semiconductor M1, the grid of grid and metal-oxide-semiconductor M2, described metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, the source electrode of metal-oxide-semiconductor M3 and metal-oxide-semiconductor M4 is connected, the grid of described metal-oxide-semiconductor M3, the grid of drain electrode and metal-oxide-semiconductor M4 connects respectively the drain electrode of described metal-oxide-semiconductor MC4, the source electrode of described metal-oxide-semiconductor MC4 connects the drain electrode of described metal-oxide-semiconductor MC3, the grid of described metal-oxide-semiconductor MC4 connects respectively the grid of described metal-oxide-semiconductor MC3 and the grid of metal-oxide-semiconductor MC2, the grid of described metal-oxide-semiconductor MC2, drain electrode connects respectively the drain electrode of described metal-oxide-semiconductor M2, the grid of described metal-oxide-semiconductor MC1, drain electrode connects respectively the drain electrode of described metal-oxide-semiconductor M2, described metal-oxide-semiconductor MC1, the source ground of metal-oxide-semiconductor MC2 and metal-oxide-semiconductor MC3, the other end ground connection of described current source Ibg.

4. Acquisition Circuit according to claim 3, it is characterized in that, described filter circuit comprises metal-oxide-semiconductor MA, metal-oxide-semiconductor MB and capacitor C 2, the grid of the grid of described metal-oxide-semiconductor MA and metal-oxide-semiconductor MB, drain electrode connect respectively the drain electrode of described metal-oxide-semiconductor M4, the source electrode of described metal-oxide-semiconductor MA is connected with the source electrode of metal-oxide-semiconductor MB, and described capacitor C 2 is in parallel to source electrode with draining of described metal-oxide-semiconductor MA.

5. Acquisition Circuit according to claim 4, is characterized in that, described metal-oxide-semiconductor M1, metal-oxide-semiconductor M2, metal-oxide-semiconductor M3, metal-oxide-semiconductor M4, metal-oxide-semiconductor MC1, metal-oxide-semiconductor MC2, metal-oxide-semiconductor MC3, metal-oxide-semiconductor MC4, metal-oxide-semiconductor MA and metal-oxide-semiconductor MB all adopt P-MOS.

6. Acquisition Circuit according to claim 5, it is characterized in that, described ratio amplification module comprises the fully-differential amplifier OTA of both-end input both-end output, two capacitor C 1, two capacitor C 2, the positive input terminal of described fully-differential amplifier OTA connects one end of capacitor C 1 described in one of them, described in one of them, capacitor C 2 is in parallel to negative output terminal with the positive input terminal of described fully-differential amplifier OTA, the negative input end of described fully-differential amplifier OTA connects wherein one end of another capacitor C 1, wherein described in another, capacitor C 2 is in parallel to positive output end with the negative input end of described fully-differential amplifier OTA, described fully-differential amplifier OTA and four electric capacity form the amplification that electric capacity ratio amplifying circuit is realized gain A v.

7. according to the Acquisition Circuit described in claim 1-6 any one, it is characterized in that, described both-end turns the amplifier A1 that single-ended amplification module comprises resistance R 1, resistance R 2, resistance R 3, resistance R 4 and the output of dual input list, the A end of described amplifier A1 connects one end of described resistance R 2, one end of described resistance R 1 connects respectively the B end of described resistance R 3 and amplifier A1, and described resistance R 4 is held to C end in parallel with the A of described amplifier A1.

8. Acquisition Circuit according to claim 7, it is characterized in that, described low-pass filtering module comprises trsanscondutance amplifier Gm1, trsanscondutance amplifier Gm2, trsanscondutance amplifier Gm3, capacitor C 1 and capacitor C 2, one end of described capacitor C 1 connects respectively the C end of described trsanscondutance amplifier Gm1, the C end of trsanscondutance amplifier Gm2, the A end of described trsanscondutance amplifier Gm3 connects respectively the A end of described trsanscondutance amplifier Gm2 and the C end of trsanscondutance amplifier Gm1, and the B end of described trsanscondutance amplifier Gm3 holds with C the one end that is connected respectively described capacitor C 2; Or described low-pass filtering module comprises resistance R 11, resistance R 12, resistance R 13, resistance R 14, capacitor C 4, capacitor C 5 and amplifier A8, one end of described resistance R 11 connects respectively one end of described resistance R 12 and one end of capacitor C 5, the other end of described resistance R 12 connects respectively one end of capacitor C 4 and the A of amplifier A8 end, the other end of described capacitor C 5 connects the C end of described amplifier A8, the B end of described amplifier A8 is contact resistance R13 and resistance R 14 respectively, and the other end of described resistance R 14 connects the C end of described amplifier A8.

9. Acquisition Circuit according to claim 8, it is characterized in that, described rear class amplification module comprises amplifier A2, resistance R 5 and resistance R 6, and the A end of described amplifier A2 connects one end of described resistance R 5, and the A of described amplifier A2 holds to C end in parallel with described resistance R 6.

10. Acquisition Circuit according to claim 9, it is characterized in that, described right lower limb driver module comprises amplifier A3, amplifier A 4, amplifier A5, amplifier A6, prime amplifier A7, resistance R 7, resistance R 8, resistance R 9, resistance R 10 resistance R _ f and capacitor C 3, after described resistance R 10 is in parallel with described resistance R _ f after connecting with described capacitor C 3, hold to C end in parallel with the A of described amplifier A6, the A end of described amplifier A6 also connects one end of described resistance R 7, the other end of described resistance R 7 connects respectively C end and the B end of described amplifier A5, the A end of described amplifier A5 connects respectively one end of described resistance R 8 and resistance R 9, the A end of described prime amplifier A7 connects respectively the other end of described resistance R 8 and the B of amplifier A3 end and C end, the B end of described prime amplifier A7 connects respectively the other end of described resistance R 9 and the B of amplifier A4 end and C end.