CN107212877A - Variable gain mixer amplifier, biological signal collecting and process chip and system - Google Patents
Variable gain mixer amplifier, biological signal collecting and process chip and system Download PDFInfo
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- CN107212877A CN107212877A CN201710375510.0A CN201710375510A CN107212877A CN 107212877 A CN107212877 A CN 107212877A CN 201710375510 A CN201710375510 A CN 201710375510A CN 107212877 A CN107212877 A CN 107212877A
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/30—Input circuits therefor
Abstract
The present invention relates to a kind of variable gain mixer amplifier, biological signal collecting and process chip and system.The chip includes variable gain mixer amplifier 11, local oscillation signal generation circuit 12, energy harvesting unit 13, the first electric capacity C1 and first resistor R1；The bio signal input Vin of variable gain mixer amplifier 11 receives bio signal, its power input VDD electrical connection energy harvestings unit 13, its local oscillation signal input LO electrical connection local oscillation signals generation circuit 12, its earth terminal GND is used to obtain outside and supply earth signal, its output end vo ut electrically connect the first electric capacity C1 first end and the first electric capacity C1 the second end be used to exporting it is modulated after audio signal；Local oscillation signal generation circuit 12 is used to receive ac signal and provides local oscillation signal after processing for variable gain mixer amplifier 11；Energy harvesting unit 13 is used to receive ac signal and provides dc source after processing for variable gain mixer amplifier 11.
Description
Technical field
The invention belongs to IC design technical field, and in particular to a kind of variable gain mixer amplifier, biological letter
Number collection with process chip and system.
Background technology
As people are constantly lifted to the demand of health and medical treatment, with wireless body area network (Wireless Body Area
Network, abbreviation WBAN) based on wearable, implantable Medical Devices it is of great interest.These medical treatment
Equipment is easy to use, it is possible to achieve the real-time monitoring to human body signal, and is sent to intelligent terminal progress data processing, for disease
The provisional monitor important in inhibiting of disease.Common bio signal includes electrocardiosignal (ECG), EEG signals (EEG) and myoelectricity
Signal (EMG) etc., these signals are very faint, and representative value is in microvolt, millivolt magnitude, and frequency is relatively low, low to acquisition system
Noiseproof feature has strict requirements.Chopping modulation technology is the noise reduction technology commonly used in bio-signals amplifier, is realized biological
Signal is separated with the frequency spectrum of low-frequency noise, so as to filter out noise.Amplified signal is transmitted by tone frequency channel wire, completed using intelligent terminal
ADC (analog-digital converter) and Digital Signal Processing can simplify front stage circuits structure.But currently with chopping modulation technology
Voice modulation system is needed using the chip such as traditional low-noise preamplifier, and there is redundant circuit in the chip causes circuit
The problem of structural area is big, power consumption is high, and because employing the intrinsic chip structure of tradition, it is impossible to chip internal circuits are carried out
Change, therefore there is very big influence for circuit function extension.
Therefore, how to develop circuit structure simple, save area, the voice modulation system of small power consumption and chip structure into
For the hot issue studied at present.
The content of the invention
In order to solve the above-mentioned problems in the prior art, the invention provides a kind of variable gain mixer amplifier,
Biological signal collecting and process chip and system.
It is mixed An embodiment provides a kind of biological signal collecting and process chip 10, including variable gain
Amplifier 11, local oscillation signal generation circuit 12, energy harvesting unit 13, the first electric capacity C1 and first resistor R1；Wherein,
The bio signal input Vin of the variable gain mixer amplifier 11 receives bio signal, its power input
VDD electrical connection energy harvestings unit 13, its local oscillation signal input LO electrical connection local oscillation signals generation circuit 12, its earth terminal
GND is used to obtain outside earth signal altogether, and its output end vo ut electrically connects the first end of the first electric capacity C1 and first electricity
Hold C1 the second end be used for export it is modulated after audio signal；
The local oscillation signal generation circuit 12 is for receiving ac signal and being the variable gain mixing after processing
Amplifier 11 provides local oscillation signal；
The energy harvesting unit 13 is for receiving ac signal and being the variable gain mixing amplification after processing
Device 11 provides dc source；
The resistance R1 is serially connected with the earth terminal GND's and the first electric capacity C1 of the variable gain mixer amplifier 11
Between second end.
In one embodiment of the invention, the variable gain mixer amplifier 11 includes the preposition mixing amplification of low noise
Device 111, programmable gain amplifier 112, bandpass filter 113 and output buffer 114；Wherein,
The preposition mixer amplifier 111 of low noise, the programmable gain amplifier 112, the bandpass filter 113
And the output buffer 114 is sequentially connected in series between the bio signal input Vin and the first electric capacity C1, and it is described
The preposition mixer amplifier 111 of low noise electrically connects the local oscillation signal input LO.
In one embodiment of the invention, the preposition mixer amplifier 111 of the low noise includes AM modulation modules 1111
With pre-amplifier module 1112；Wherein, the AM modulation modules 1111 and the pre-amplifier module 1112 are sequentially connected in series
Between the bio signal input Vin and the programmable gain amplifier 112, and the AM modulation modules 1111 are electrically connected
Meet the local oscillation signal input LO.
In one embodiment of the invention, the local oscillation signal generation circuit 12 includes biasing circuit 121 and signal is whole
Shape circuit 122, the biasing circuit 121 and the signal transformation circuit 122, which are sequentially connected in series to the variable gain to be mixed, to be amplified
The local oscillation signal input LO of device 11, and the input of the biasing circuit 121 receives the ac signal.
In one embodiment of the invention, the signal transformation circuit 122 includes：5th transistor M5, the 6th crystal
Pipe M6, the 7th transistor M7, the first phase inverter INV1, the second phase inverter INV2, the 3rd phase inverter INV3, the 4th phase inverter
INV4, second resistance R2,3rd resistor R3；Wherein,
The second resistance R2, the 5th transistor M5 and the 7th transistor M7 be sequentially connected in series in dc source and
Between earth terminal, the control end input coupling signal VSIN of the 5th transistor M5, the control end of the 7th transistor M7
Input offset voltage VBIAS；
The 3rd resistor R3 and the 6th transistor M6 are sequentially connected in series in the dc source and the 5th transistor M5
And the 7th transistor M7 concatenates to be formed between node G, the control end input reference voltage VREF of the 6th transistor M6；
The first phase inverter INV1 and the second phase inverter INV2 is sequentially connected in series to the second resistance R2 and the 5th
Transistor M5 is concatenated at the node E to be formed, and the output end of the first phase inverter INV1 electrically connects the variable gain mixing
The local oscillation signal input LO of amplifier 11 is to export the first local oscillation signal；
The 4th phase inverter INV4 and the 3rd phase inverter INV3 is sequentially connected in series to the 3rd resistor R3 and the 6th
Transistor M6 is concatenated at the node F to be formed, and the 4th phase inverter INV4 electrically connects the variable gain mixer amplifier 11
Local oscillation signal input LO to export the second local oscillation signal.
In one embodiment of the invention, the energy harvesting unit 13 includes rectifier 131, overvoltage crowbar
132 and LDO133；Wherein, the rectifier 131, the overvoltage crowbar 132 and the LDO133 are sequentially connected in series to described
The power input VDD of variable gain mixer amplifier 11 is to provide dc source, and the rectifier 131 receives the exchange
Electric signal.
An alternative embodiment of the invention provides a kind of variable gain mixer amplifier 11, including the low noise being sequentially connected in series
The preposition mixer amplifier 111 of sound, programmable gain amplifier 112, bandpass filter 113, output buffer 114, and it is described low
The first input end of the preposition mixer amplifier 111 of noise receives bio signal and its second input receives local oscillation signal.
In one embodiment of the invention, the AM that the preposition mixer amplifier 111 of the low noise includes being sequentially connected in series is adjusted
Molding block 1111 and pre-amplifier module 1112；The signal input part of the AM modulation modules 1111 receives the bio signal
And its local oscillator input receives the local oscillation signal, the output end electrical connection of the pre-amplifier module 1112 is described programmable
Gain amplifier 112.
In one embodiment of the invention, the AM modulation modules 1111 include the first transistor M1, second transistor
M2, third transistor M3 and the 4th transistor M4；The signal input part of the AM modulation modules 1111 is inputted including the first signal
IN+ and secondary signal input IN- is held, the local oscillator input of the AM modulation modules 1111 includes the first local oscillator input LO+
With the second local oscillator input LO-, the output end of the AM modulation modules 1111 includes in-phase output end OUT+ and reversed-phase output
OUT-；Wherein,
The first transistor M1 is serially connected between the first signal input part IN+ and the in-phase output end OUT+,
And its control end is electrically connected to the first local oscillator input LO+；
The second transistor M2 is serially connected between the first signal input part IN+ and the reversed-phase output OUT-,
And its control end is electrically connected to the second local oscillator input LO-；
The third transistor M3 is serially connected between the secondary signal input IN- and the in-phase output end OUT+,
And its control end is electrically connected to the second local oscillator input LO-；
The 4th transistor M4 is serially connected between the secondary signal input IN- and the reversed-phase output OUT-,
And its control end is electrically connected to the first local oscillator input LO+.
Another embodiment of the present invention provides a kind of biological signal collecting and processing system 1, including bio signal is adopted
Collection and process chip 10, earphone interface 20, bioelectrode 30 and terminal 40, the biological signal collecting are electrically connected with process chip 10
Connect the bioelectrode 30 and the bio signal after gathering and modulating is sent to the terminal 40 by the earphone interface 20；Its
In, described biological signal collecting and processing that the biological signal collecting and process chip 10 provide for any of the above-described embodiment
Chip 10.
By above-mentioned embodiment, biological signal collecting of the invention and process chip are by whole Signal acquiring and processing collection
Among Cheng Yi IC chip, the modulation, amplification and transmission of bio signal can be completed.In addition, the chip modulates audio A M
Combined with wave chopping technology, the modulation of redundancy twice, only passes through primary modulation after eliminating during modulation-demodulation-re-modulation, can
To modulate the signal to audio, while modulation realizes signal and separated with the frequency spectrum of noise, reduced and made an uproar by rear class filtering device
Sound, serves the effect of chopping modulation.Due to the adjustable gain of variable gain mixer amplifier, the chip can be to variety classes
Bio signal (electrocardiosignal, EEG signals, electromyographic signal etc.) be acquired and handle.In addition, the biological signal collecting with
Processing system makes full use of two sound channels of 3.5mm earphone cords, and supply voltage and stable local oscillation signal are provided for system.
Brief description of the drawings
Fig. 1 is a kind of biological signal collecting provided in an embodiment of the present invention and the electrical block diagram of processing system；
Fig. 2 is a kind of biological signal collecting provided in an embodiment of the present invention and the electrical block diagram of process chip；
Fig. 3 is a kind of electrical block diagram of variable gain mixer amplifier provided in an embodiment of the present invention；
Fig. 4 is a kind of electrical block diagram of the preposition mixer amplifier of low noise provided in an embodiment of the present invention；
Fig. 5 is a kind of circuit structure contrast schematic diagram of variable gain mixer amplifier provided in an embodiment of the present invention；
A kind of Fig. 6 circuit diagrams of AM modulation modules provided in an embodiment of the present invention；
Fig. 7 is a kind of electrical block diagram of local oscillation signal generation circuit provided in an embodiment of the present invention；
Fig. 8 is a kind of circuit diagram of signal transformation circuit provided in an embodiment of the present invention；
Fig. 9 is a kind of electrical block diagram of energy harvesting unit provided in an embodiment of the present invention；
Figure 10 is a kind of electrical block diagram of rectifier provided in an embodiment of the present invention；
Figure 11 is a kind of circuit diagram of excess voltage protection provided in an embodiment of the present invention.
Embodiment
Further detailed description is done to the present invention with reference to specific embodiment, but embodiments of the present invention are not limited to
This.
Embodiment one
Fig. 1 is referred to, Fig. 1 is a kind of biological signal collecting provided in an embodiment of the present invention and the circuit structure of processing system
Schematic diagram.The biological signal collecting and processing system 1 can include biological signal collecting and process chip 10, earphone interface 20,
Bioelectrode 30 and terminal 40.Wherein, the biological signal collecting electrically connects the bioelectrode 30 with process chip 10 and logical
Cross the earphone interface 20 and the bio signal after gathering and modulating is sent to the terminal 40.The system 1 can be to variety classes
Bio signal (such as electrocardiosignal, EEG signals, electromyographic signal etc.) be acquired and handle.
Specifically, adopted with gathering bio signal at the position to be collected that bioelectrode 30 is attached at organism (such as human body)
The bio signal collected is modulated and enhanced processing by biological signal collecting and process chip 10, i.e., be modulated into bio signal
Audio signal simultaneously realizes that signal separates with the frequency spectrum of noise and reduces noise, afterwards will with process chip 10 by biological signal collecting
The bio signal for forming audio is transmitted to terminal 40 (such as smart mobile phone) by earphone interface 20, and the APP in terminal 40 enters
Row data reprocess to show user for user referring to the bio signal situation collected.
Wherein, the earphone interface 20 is, for example, 3.5mm earphone interfaces, and it includes left channel data interface, right data
Interface, altogether interface and MIC interfaces.
Fig. 2 is referred to, Fig. 2 is a kind of biological signal collecting provided in an embodiment of the present invention and the circuit structure of process chip
Schematic diagram.The chip 10 can include variable gain mixer amplifier 11, local oscillation signal generation circuit 12, energy harvesting unit
13rd, the first electric capacity C1 and first resistor R1.Wherein, the bio signal input Vin of the variable gain mixer amplifier 11 connects
Receive bio signal, its power input VDD electrical connection energy harvestings unit 13, its local oscillation signal input LO electrical connection local oscillator letters
Number generation circuit 12, its earth terminal GND is used to obtain outside earth signal altogether, and its output end vo ut electrically connects the first electric capacity C1
First end and the first electric capacity C1 the second end be used for export it is modulated after audio signal；The local oscillation signal produces electricity
Road 12 is for receiving ac signal and being that the variable gain mixer amplifier 11 provides local oscillation signal after processing；The energy
Amount acquiring unit 13 is for receiving ac signal and being that the variable gain mixer amplifier 11 provides direct current after processing
Source；The resistance R1 is serially connected with the second of the earth terminal GND and the first electric capacity C1 of the variable gain mixer amplifier 11
Between end.
Wherein, the bio signal is provided by bioelectrode 30；The ac signal that energy harvesting unit 13 is received can lead to
The left channel interface for crossing earphone interface 20 is obtained from terminal 40；The ac signal of local oscillation signal generation circuit can pass through ear
The right channel interface of machine interface 20 is obtained from terminal 40；It can be connect by the first electric capacity C1 audio signals exported by earphone
The MIC interfaces of mouth 20 are transmitted to terminal 40；Earth terminal GND common earth signal can by the common ground interface of earphone interface 20 from
Obtained at terminal 40.
Specifically, the bio signal that bioelectrode is collected first is modulated to audio (such as by variable gain mixer amplifier 11
5kHz), amplify further according to different types of bio signal according to suitable gain, for rear class processing.Wherein, variable gain is mixed
Audio amplifier 11 local oscillation signal input LO (Local Oscillator) electrical connection local oscillation signal generation circuit 12 with by
The local oscillation signal generation circuit 12 produces stable local oscillator oscillator signal, for AM modulation；Variable gain mixer amplifier 11
Power input VDD electrically connects energy harvesting unit 13 to provide DC voltage by the energy harvesting unit 13, is that chip 10 is supplied
Electricity；First electric capacity C1 of the output end vo ut electrical connections of variable gain mixer amplifier 11 first end is with by first electric capacity C1
Couples high frequency modulated signal；The first resistor R1 of first electric capacity C1 the second end connection is with by first resistor R1 detections MIC
Low-resistance input so that modulation after audio signal pass through MIC interfaces access terminal 40.
The present embodiment, the input of local oscillation signal generation circuit 12 and the input of energy harvesting unit 13 respectively with it is external
R channel and the L channel connection of 3.5mm earphone cords, the energy harvesting unit are exported L channel by internal rectifier
Fixed frequency sinusoidal signal is converted to DC voltage to provide power supply for chip, and the local oscillation signal generation circuit is defeated by R channel
The sinusoidal signal gone out is shaped as square-wave signal to provide local oscillation signal, the biology of 11 pairs of inputs of variable gain mixer amplifier
Signal is modulated and amplified, and couples a signal to output end (the MIC inputs of 3.5mm earphone cords by coupled capacitor C1
End).
Embodiment two
Please also refer to Fig. 3 to Fig. 6, Fig. 3 is a kind of electricity of variable gain mixer amplifier provided in an embodiment of the present invention
Line structure schematic diagram；Fig. 4 is a kind of electrical block diagram of the preposition mixing amplification of low noise provided in an embodiment of the present invention；Figure
5 be a kind of circuit structure contrast schematic diagram of variable gain mixer amplifier provided in an embodiment of the present invention；Fig. 6 present invention are real
A kind of circuit diagram of AM modulation modules of example offer is provided.The present embodiment is on the basis of above-described embodiment, to variable gain
The circuit of mixer amplifier is described in detail.
Refer to Fig. 3, the variable gain mixer amplifier 11 can include the preposition mixer amplifier 111 of low noise, can
Program gain amplifier 112, bandpass filter 113 and output buffer 114；Wherein, the preposition mixer amplifier of the low noise
111st, the programmable gain amplifier 112, the bandpass filter 113 and the output buffer 114 are sequentially connected in series in institute
State between bio signal input Vin and the first electric capacity C1, and the preposition electrical connection of mixer amplifier 111 institute of the low noise
State local oscillation signal input LO.
It should be noted that the common earth signal and electricity of the earth terminal GND accesses due to the variable gain mixer amplifier 11
The dc source of source input VDD accesses is for the preposition mixer amplifier of low noise 111, programmable gain amplifier 112, band logical
Wave filter 113 and output buffer 114 are both needed to use, and in order to illustrate simplicity, do not mark.
Specifically, the preposition mixer amplifier 111 of the low noise first will under conditions of ensureing that itself introduces very little noise
The bio signal of the bioelectrode collection is modulated to audio, then carries out first order amplification, the programmable gain amplifier 112
Adjustable gain, suitable gain can be selected according to the power of the bio signal amplified, to avoid output signal from making greatly very much to put
Big device saturation or output signal is too small is difficult to detect.Because the bio signal modulated by AM is located at audio (such as 5kHz), simultaneously
Modulation can produce high-frequency harmonic, and the 1/f noise of amplifier and lack of proper care it is non-modulated, positioned at low frequency, therefore the bandpass filtering
Device 113 is used to filter out high-frequency harmonic and the imbalance positioned at low frequency and noise, obtains more pure modulated signal.It is anti-in order to improve
Interference performance, the preposition mixer amplifier 111 of low noise, programmable gain amplifier 112, bandpass filter 113 are used
Differential Input and difference output.The output buffer 114 is used to differential signal being converted into single-end output signal, and drives negative
Carry.
Fig. 4 is referred to, the preposition mixer amplifier 111 of the low noise can include AM modulation modules 1111 and preamplifier
Module 1112；Wherein, the AM modulation modules 1111 and the pre-amplifier module 1112 are sequentially connected in series in the biological letter
Number between input Vin and the programmable gain amplifier 112, and the AM modulation modules 1111 electrically connect the local oscillator letter
Number input LO.
Refer to Fig. 5, prior art, because bio signal is very faint, before generally being reduced using chopping modulation technology
Put the noise of amplifier.Traditional structure modulated afterwards of first amplifying needs to use three modulation modules (chopping modulation, copped wave solution
Adjust, AM is modulated) and two low pass filters, wherein, chopping modulation realizes that signal is separated with the frequency spectrum of noise with copped wave demodulation, the
One low pass filter is used to filter out the 1/f noise for being modulated onto high frequency and imbalance；AM is modulated for by the signal modulation of amplification
To audio, second low pass filter is used to filter out high-frequency harmonic.Signal experienced the process of modulation-demodulation-re-modulation, and defeated
The signal gone out is high frequency, and redundancy is modulated twice after institute.Structure of the present invention only needs to carry out before preamplifier after simplification
Primary modulation, can either modulate the signal to audio (such as 5kHz), can realize that signal is separated with the frequency spectrum of noise, is played and is cut again
The effect of ripple modulation, non-modulated low-frequency noise and imbalance, and the high-frequency harmonic that modulation is produced are filtered by a band logical of rear class
Ripple device is filtered out.That is, the output of AM modulation modules 1111 is connected with the input of preamplifier 1112, AM modulation modules 1111 are used
Audio is modulated in the bio signal for gathering bioelectrode, meanwhile, similar to the thought of chopping modulation, due to imbalance and 1/f
Noise is not modulated, and is realized signal and is separated with the frequency spectrum of noise, and filtering out low frequency by the bandpass filter of rear class lacks of proper care, and makes an uproar
Sound and high-frequency harmonic, to reduce the noise of the preposition mixer amplifier 111 of whole low noise.Preamplifier 1112 is used for biology
Signal carries out first order amplification.
Specifically, Fig. 6 is referred to, the AM modulation modules 1111 can include the first transistor M1, second transistor M2, the
Three transistor M3 and the 4th transistor M4；The signal input part of the AM modulation modules 1111 includes the first signal input part IN+
With secondary signal input IN-, the local oscillator input of the AM modulation modules 1111 includes the first local oscillator input LO+ and second
Local oscillator input LO-, the output end of the AM modulation modules 1111 includes in-phase output end OUT+ and reversed-phase output OUT-；Its
In, the first transistor M1 is serially connected between the first signal input part IN+ and the in-phase output end OUT+, and it is controlled
End processed is electrically connected to the first local oscillator input LO+；The second transistor M2 is serially connected with the first signal input part IN+
Between the reversed-phase output OUT-, and its control end is electrically connected to the second local oscillator input LO-；3rd crystal
Pipe M3 is serially connected between the secondary signal input IN- and the in-phase output end OUT+, and its control end is electrically connected to institute
State the second local oscillator input LO-；The 4th transistor M4 is serially connected with the secondary signal input IN- and the anti-phase output
Between the OUT- of end, and its control end is electrically connected to the first local oscillator input LO+.Wherein, in order to simplify diagram, not by crystalline substance
Earth signal is shown in figure altogether for the substrate terminal connection of body pipe.
Wherein, LO+ and LO- is the square-wave signal for two opposite in phase that local oscillation signal is produced, IN+ and IN- and biological electricity
The difference output connection of pole, when LO+ is high level and LO- is low level, the conducting of switching transistor M1, M4, M2, M3 shut-off,
Now IN+ input signals pass to OUT+ by M1, and IN- input signals pass to OUT- by M4, when local oscillation signal is overturn, LO+
Jump to low level and LO- jumps to high level, now switching transistor M2, the M3 conducting, M1, M4 shut-off, IN+ input letters
Number OUT- is now passed to by M2, IN- signals pass to OUT+ by M3.Carry out switchback due to being input to outgoing route with local oscillation signal
Change, realize the mixing of low frequency bio signal and high-frequency local oscillation signal, i.e. AM modulation.
Bio signal is modulated to audio by the present embodiment, the variable gain mixer amplifier, while being dropped using copped wave principle
Low noise, eliminates the modulation module of latter two redundancy in modulation-demodulation-re-modulation, through ovennodulation and the signal after amplification
Audio can be modulated to very low loss and distortion transmission by the chip by being inputted by earphone interface to intelligent terminal
Bio signal.
Embodiment three
It is a kind of circuit structure of local oscillation signal generation circuit provided in an embodiment of the present invention to refer to Fig. 7 and Fig. 8, Fig. 7
Schematic diagram；Fig. 8 is a kind of circuit diagram of signal transformation circuit provided in an embodiment of the present invention.The present embodiment is in above-mentioned implementation
On the basis of example, local oscillation signal generation circuit is described in detail.
Fig. 7 is referred to, the local oscillation signal generation circuit 12 can include biasing circuit 121 and signal transformation circuit 122,
The biasing circuit 121 and the signal transformation circuit 122 are sequentially connected in series to the local oscillator of the variable gain mixer amplifier 11
Signal input part LO, and the input of the biasing circuit 121 receives the ac signal.Wherein, the biasing circuit 121
Input be connected with right channel input signal, output is connected with the input of the signal transformation circuit 122, and the signal shaping is electric
The output on road is connected with the local oscillation signal input LO of the variable gain mixer amplifier 11.The sine exported due to R channel
Signal common mode electrical level not can determine that biasing circuit 121 is used to couple right channel output signal, and determines signal transformation circuit 122
Input common mode electrical level (close to VDD/2), signal transformation circuit 122 be used for sinusoidal signal is shaped as square-wave signal.
Specifically, Fig. 8 is referred to, the signal transformation circuit 122 includes：5th transistor M5, the 6th transistor M6,
Seven transistor M7, the first phase inverter INV1, the second phase inverter INV2, the 3rd phase inverter INV3, the 4th phase inverter INV4, the second electricity
Hinder R2,3rd resistor R3；Wherein, the second resistance R2, the 5th transistor M5 and the 7th transistor M7 go here and there successively
It is connected between dc source and earth terminal, the control end input coupling signal VSIN of the 5th transistor M5, the described 7th is brilliant
Body pipe M7 control end input offset voltage VBIAS；The 3rd resistor R3 and the 6th transistor M6 are sequentially connected in series in described straight
Stream power supply is concatenated and formed between node G with the 5th transistor M5 and the 7th transistor M7, the 6th transistor M6
Control end input reference voltage VREF；The first phase inverter INV1 is sequentially connected in series to described with the second phase inverter INV2
Second resistance R2 and the 5th transistor M5 are concatenated at the node E to be formed, and the output end electrical connection of the first phase inverter INV1
The local oscillation signal input LO of the variable gain mixer amplifier 11 is to export the first local oscillation signal；4th phase inverter
INV4 is sequentially connected in series to the 3rd resistor R3 and the 6th transistor M6 with the 3rd phase inverter INV3 and concatenates the node F to be formed
Locate, and the 4th phase inverter INV4 electrically connects the local oscillation signal input LO of the variable gain mixer amplifier 11 to export
Second local oscillation signal.That is, the 7th transistor M7 grid is connected with bias voltage VBIAS, source ground, drain electrode is brilliant with the 5th
Body pipe M5, the 6th transistor M6 source electrode connection, the grid of the 5th transistor M5 are connected with R channel coupled signal VSIN,
Drain electrode is connected with the negative terminal of the load resistance R2, and is connected by described phase inverter INV2, INV1 and the first local oscillation signal LO-
Connect, the grid of the 6th transistor M6 is connected with reference voltage VREF, drain electrode is connected with the negative terminal of the load resistance R3, and
It is connected by described phase inverter INV3, INV4 with the second local oscillation signal LO+, described load resistance R2, R3 anode and VDD connect
Connect.
The way of realization of the signal transformation circuit 122 is similar to a comparator, and amplifier open-loop is used, Differential Input
R channel coupled signal VSIN is accessed in one end, and another termination reference voltage VREF (close to VDD/2) passes through the shaping of amplifier
Effect, sinusoidal signal edge becomes precipitous, in the square-wave signal (LO+ and LO-) of difference output end two opposite in phase of formation, figure
As can be seen that LO+ and the input same phase of sinusoidal signal, LO- and input sinusoidal signal are anti-phase, the second resistance R2,3rd resistor
R3 is used for setting the gain of amplifier, and gain is bigger, and output signal edge is more precipitous, and obtained square wave is more preferable, described anti-phase
Device is used for further shaping square-wave signal.
Example IV
Fig. 9 is referred to Figure 11；Fig. 9 illustrates for a kind of circuit structure of energy harvesting unit provided in an embodiment of the present invention
Figure；Figure 10 is a kind of electrical block diagram of rectifier provided in an embodiment of the present invention；Figure 11 provides for the embodiment of the present invention
A kind of excess voltage protection circuit diagram.This implementation is entered on the basis of above-described embodiment to energy harvesting unit
Row is described in detail.
The energy harvesting unit 13 can include rectifier 131, overvoltage crowbar 132 and LDO (low pressure difference linearities
Voltage-stablizer) 133, the rectifier 131, the overvoltage crowbar 132 and the LDO133 are sequentially connected in series to the variable increasing
The power input VDD of beneficial mixer amplifier 11 is to provide dc source, and the rectifier 131 receives the exchange telecommunications
Number.Wherein, the rectifier 131 and overvoltage crowbar 132 realize AC-DC converter function, the sine that L channel is exported
Signal carries out rectification, and exports galvanic current pressure by LDO 133 and powered to rear class.
Figure 10 is referred to, the rectifier 131 includes the second electric capacity C2, the 3rd electric capacity C3, the 4th electric capacity C4, the 5th electric capacity
C5, the 8th transistor M8, the 9th transistor M9, the tenth transistor M10, the 11st transistor M11, first comparator COMP1,
Two comparator COMP2, the 3rd comparator COMP3 and the 4th comparator COMP4；Wherein, the source electrode of the 8th transistor M8 with
First comparator COMP1 in-phase input end electrical connection, drain electrode is electrically connected with first comparator COMP1 inverting input, grid
Pole is electrically connected with first comparator COMP1 output end；The source electrode of the 9th transistor M9 is same with the second comparator COMP2's
Phase input is electrically connected, and drain electrode is electrically connected with the second comparator COMP2 inverting input, grid and the second comparator COMP2
Output end electrical connection；The source electrode of the tenth transistor M10 is electrically connected with the 3rd comparator COMP3 in-phase input end, leakage
Pole is electrically connected with the 3rd comparator COMP3 inverting input, and grid is electrically connected with the 3rd comparator COMP3 output end；Institute
The source electrode for stating the 11st transistor M11 is electrically connected with the 4th comparator COMP4 in-phase input end, drain electrode and the 4th comparator
COMP4 inverting input electrical connection, grid is electrically connected with the 4th comparator COMP4 output end；Input VIN` with it is described
Second electric capacity C2, the 3rd electric capacity C3 anode electrical connection, the drain electrode electricity of the second electric capacity C2 negative terminal and the 8th transistor M8
Connection, and electrically connected with the 9th transistor M9 source electrode, the 9th transistor M9 drain electrode and the anode electricity of the 4th electric capacity C4
Connection, and electrically connected with the source electrode of the tenth transistor M10, the tenth transistor M10 drain electrode and the 3rd electric capacity C3 negative terminal
Electrical connection, and electrically connected with the 11st transistor M11 source electrode, the 11st transistor M11 drain electrode and the 5th electric capacity C5 are just
End electrical connection, and it is electrically connected to output end VOUT`, the 4th electric capacity C4, the 5th electric capacity C5 negativing ending grounding.
The rectifier of the present embodiment, using the topological structure of the charge pump rectifier based on active diode, wherein integrated
Active diode can realize tens millivolts of conduction voltage drop, compared with conventional diode rectifier, substantially increase rectification
Efficiency, reduces rectifier series.Supply voltage according to needed for different input signal amplitude scopes and system is whole to adjust
The series of device is flowed to meet needs.For example, earphone sound channel output voltage peak-to-peak value is more than 0.7V smart mobile phone as input
Source, when voice modulation biological signal collecting and process chip supply voltage as little as 1.2V when, two-stage rectifier is just in theory
Requirement can be met (assuming that LDO minimum comes off, voltage is 200mV).
Figure 11 is referred to, overvoltage crowbar 132 can include the 6th electric capacity C6, the first diode D1, the second diode
D2, the 3rd diode D3；Wherein, signal input part VIN`` is electrically connected with the anode of the 6th electric capacity C6, and with described first
Diode D1 positive pole electrical connection, the 6th electric capacity C6 negativing ending grounding, the first diode D1 negative pole and the second diode D2's
Positive pole is electrically connected, and the second diode D2 negative pole is electrically connected with the 3rd diode D3 positive pole, and the 3rd diode D3 negative pole connects
Ground, output end VOUT`` electrically connects the first diode D1 positive pole.
The overvoltage crowbar of the present embodiment, for preventing overtension breakdown transistors, due to different intelligent mobile phone ear
The peak-peak voltage of machine sound channel output is different (hundreds of millivolts are arrived several volts), and the possible amplitude of signal after rectifier boost is very
Greatly, different process is allowed ceiling voltage is different, by storage capacitor (C6) anode connect some diodes to, can be by
Ceiling voltage is restricted to the conduction voltage drop sum (being the N of three times, about 1.8V in Figure 11) of these diodes,
When the voltage on storage capacitor is higher than this maximum, diode is both turned on, by the tension discharge on storage capacitor to limit
Value processed.
To sum up, specific case used herein is set forth to the principle and embodiment of the present invention, and the above is implemented
The explanation of example is only intended to the method and its core concept for helping to understand the present invention；Simultaneously for the general technology people of this area
Member, according to the thought of the present invention, will change, to sum up, in this specification in specific embodiments and applications
Appearance be should not be construed as limiting the invention, and protection scope of the present invention should be defined by appended claim.
Claims (10)
1. a kind of biological signal collecting and process chip (10), it is characterised in that including variable gain mixer amplifier (11), originally
Shake signal generating circuit (12), energy harvesting unit (13), the first electric capacity (C1) and first resistor (R1)；Wherein,
The bio signal input (Vin) of the variable gain mixer amplifier (11) receives bio signal, its power input
(VDD) electrical connection energy harvesting unit (13), its local oscillation signal input (LO) electrical connection local oscillation signal generation circuit (12), its
Earth terminal (GND) is used to obtain outside earth signal altogether, and its output end (Vout) electrically connects the first end of first electric capacity (C1)
And the second end of first electric capacity (C1) be used for export it is modulated after audio signal；
The local oscillation signal generation circuit (12) is for receiving ac signal and being that the variable gain mixing is put after processing
Big device (11) provides local oscillation signal；
The energy harvesting unit (13) is for receiving ac signal and being the variable gain mixer amplifier after processing
(11) dc source is provided；
The resistance R1 is serially connected with the earth terminal (GND) of the variable gain mixer amplifier (11) and first electric capacity (C1)
The second end between.
2. chip (10) according to claim 1, it is characterised in that the variable gain mixer amplifier (11) includes low
The preposition mixer amplifier of noise (111), programmable gain amplifier (112), bandpass filter (113) and output buffer
(114)；Wherein,
The preposition mixer amplifier of low noise (111), the programmable gain amplifier (112), the bandpass filter
And the output buffer (114) is sequentially connected in series in the bio signal input (Vin) and first electric capacity (C1) (113)
Between, and the preposition mixer amplifier of the low noise (111) electrically connects the local oscillation signal input (LO).
3. chip (10) according to claim 2, it is characterised in that the preposition mixer amplifier of low noise (111) bag
Include AM modulation modules (1111) and pre-amplifier module (1112)；Wherein, AM modulation modules (1111) and described preposition
Amplifier module (1112) is sequentially connected in series in the bio signal input (Vin) and the programmable gain amplifier (112)
Between, and the AM modulation modules (1111) electrically connect the local oscillation signal input (LO).
4. chip (10) according to claim 1, it is characterised in that the local oscillation signal generation circuit (12) includes biasing
Circuit (121) and signal transformation circuit (122), the biasing circuit (121) and the signal transformation circuit (122) are sequentially connected in series
The extremely local oscillation signal input (LO) of the variable gain mixer amplifier (11), and the input of the biasing circuit (121)
Receive the ac signal.
5. chip (10) according to claim 4, it is characterised in that the signal transformation circuit (122) includes：5th is brilliant
Body pipe (M5), the 6th transistor (M6), the 7th transistor (M7), the first phase inverter (INV1), the second phase inverter (INV2), the 3rd
Phase inverter (INV3), the 4th phase inverter (INV4), second resistance (R2), 3rd resistor (R3)；Wherein,
The second resistance (R2), the 5th transistor (M5) and the 7th transistor (M7) are sequentially connected in series in dc source
Between earth terminal, the control end input coupling signal (VSIN) of the 5th transistor (M5), the 7th transistor (M7)
Control end input offset voltage (VBIAS)；
The 3rd resistor (R3) and the 6th transistor (M6) are sequentially connected in series in the dc source and the 5th transistor
(M5) formed with the 7th transistor (M7) concatenation between node (G), the control end input ginseng of the 6th transistor (M6)
Examine voltage (VREF)；
First phase inverter (INV1) and second phase inverter (INV2) are sequentially connected in series to the second resistance (R2) and the
Node (E) place that five transistors (M5) concatenation is formed, and the output end electrical connection of first phase inverter (INV1) is described variable
The local oscillation signal input (LO) of gain mixer amplifier (11) is to export the first local oscillation signal；
4th phase inverter (INV4) and the 3rd phase inverter (INV3) are sequentially connected in series to the 3rd resistor (R3) and the
Node (F) place that six transistors (M6) concatenation is formed, and the 4th phase inverter (INV4) electrically connects the variable gain mixing
The local oscillation signal input (LO) of amplifier (11) is to export the second local oscillation signal.
6. chip (10) according to claim 1, it is characterised in that the energy harvesting unit (13) includes rectifier
(131), overvoltage crowbar (132) and LDO (133)；Wherein, the rectifier (131), the overvoltage crowbar (132)
And the LDO (133) is sequentially connected in series to the power input (VDD) of the variable gain mixer amplifier (11) to provide direct current
Power supply, and the rectifier (131) receives the ac signal.
7. a kind of variable gain mixer amplifier (11), it is characterised in that the preposition mixing amplification of the low noise including being sequentially connected in series
Device (111), programmable gain amplifier (112), bandpass filter (113), output buffer (114), and before the low noise
The first input end for putting mixer amplifier (111) receives bio signal and its second input reception local oscillation signal.
8. variable gain mixer amplifier (11) according to claim 7, it is characterised in that the preposition mixing of the low noise
Amplifier (111) includes the AM modulation modules (1111) and pre-amplifier module (1112) being sequentially connected in series；The AM modulates mould
The signal input part of block (1111) receives the bio signal and its local oscillator input receives the local oscillation signal, the preceding storing
The output end of big device module (1112) electrically connects the programmable gain amplifier (112).
9. variable gain mixer amplifier (11) according to claim 8, it is characterised in that the AM modulation modules
(1111) the first transistor (M1), second transistor (M2), third transistor (M3) and the 4th transistor (M4) are included；The AM
The signal input part of modulation module (1111) includes the first signal input part (IN+) and secondary signal input (IN-), the AM
The local oscillator input of modulation module (1111) includes the first local oscillator input (LO+) and the second local oscillator input (LO-), the AM
The output end of modulation module (1111) includes in-phase output end (OUT+) and reversed-phase output (OUT-)；Wherein,
The first transistor (M1) be serially connected with first signal input part (IN+) and the in-phase output end (OUT+) it
Between, and its control end is electrically connected to the first local oscillator input (LO+)；
The second transistor (M2) be serially connected with first signal input part (IN+) and the reversed-phase output (OUT-) it
Between, and its control end is electrically connected to the second local oscillator input (LO-)；
The third transistor (M3) be serially connected with the secondary signal input (IN-) and the in-phase output end (OUT+) it
Between, and its control end is electrically connected to the second local oscillator input (LO-)；
4th transistor (M4) be serially connected with the secondary signal input (IN-) and the reversed-phase output (OUT-) it
Between, and its control end is electrically connected to the first local oscillator input (LO+).
10. a kind of biological signal collecting and processing system (1), it is characterised in that including biological signal collecting and process chip
(10), earphone interface (20), bioelectrode (30) and terminal (40), the biological signal collecting are electrically connected with process chip (10)
The bioelectrode (30) and being sent by the earphone interface (20) to the terminal (40) gathers and biological after modulating is believed
Number；Wherein, the biological signal collecting and process chip (10) are the biological signal collecting described in any one of claim 1~6
With process chip (10).
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Cited By (1)
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| CN110638443A (en) * | 2019-11-07 | 2020-01-03 | 福州大学 | Electrocardiosignal reading circuit |
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