CN215773056U - Weak signal amplification shaping circuit applied to blood analyzer - Google Patents
Weak signal amplification shaping circuit applied to blood analyzer Download PDFInfo
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- CN215773056U CN215773056U CN202121765196.5U CN202121765196U CN215773056U CN 215773056 U CN215773056 U CN 215773056U CN 202121765196 U CN202121765196 U CN 202121765196U CN 215773056 U CN215773056 U CN 215773056U
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Abstract
The utility model relates to the technical field of pulses, and discloses a weak signal amplification and shaping circuit applied to a blood analyzer. The high pass filter filters out low frequency noise interference. The second infinite gain multipath feedback low pass filter amplifies the preceding stage signal and filters out unwanted high frequency interference signals. The negative feedback amplification rectification module is used for amplifying signals and shaping waveforms. Meanwhile, the channels are switched to carry out different amplification gains, the voltage follower ensures that signals are output to the next stage as lossless as possible in transmission, and the output end of the protection circuit adjusts the threshold voltage, so that the band-pass filter has the function of a band-pass filter, reduces noise, can extract and amplify weak pulse signals, and is high in anti-interference capacity.
Description
Technical Field
The utility model relates to the technical field of pulses, in particular to a weak signal amplification shaping circuit applied to a blood analyzer.
Background
The blood analyzer can provide blood count classification in clinical examination, etc. And providing data support for the diagnosis of doctors. The five-classification of blood cells refers to the five-classification examination of white blood cells, namely, when the blood test is routine, the white blood cells are classified into five classes, and the number of the five classes of white blood cells is respectively counted, wherein the five classes of white blood cells comprise neutrophils, eosinophils, basophils, monocytes and lymphocytes, and because the sizes and the cell complexity of the 5 types of white blood cells are different, based on the flow cytometry, a sheath flow wraps a cell suspension liquid to pass through an illumination area at a constant speed, and the cells are irradiated by laser in the illumination area, and because the sizes, the shapes and the complexity of the cells are different, the scattered light intensity is different at different angles. The characteristics of the cells are obtained by collecting light intensity signals scattered by the cells in the laser irradiation sheath flow at various angles. But the pulse signal is weak. For various weak signals to be measured, the signals are generally converted into low voltage by corresponding sensors, and then amplified by an amplifier.
Because the measured signal is weak, the background noise of the sensor, the inherent noise of the amplifying circuit and the measuring instrument and the external interference noise are usually much larger than the amplitude of the useful signal, the noise is amplified in the process of amplifying the measured signal, and extra noise such as the internal inherent noise and the external interference noise of the amplifier is added, so that the weak signal cannot be detected only by amplification. The useful signal can be extracted only by increasing the amplitude of the weak signal under the condition of effectively suppressing the noise. The blood analyzer can classify the white blood cells and test the reticulocytes and related parameters. Since reticulocyte signals are weaker than leukocyte signals, they are more difficult to test. The common method is that the front stage sets a set of amplification factor and is compatible with the amplification of reticulocyte signals and leukocyte classification signals, but the method has insufficient adjustable margin, if the light path system changes slightly in the later stage, the signal amplification factor is too large for classifying leukocytes, but the amplification factor is not enough for reticulocyte signals.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a weak signal amplification and shaping circuit applied to a blood analyzer, aiming at extracting and amplifying weak pulse signals and improving the anti-interference capability.
In order to achieve the above object, the present invention provides a weak signal amplifying and shaping circuit applied in a blood analyzer, which includes a photoelectric signal input end, an IV conversion circuit connected to the photoelectric signal input end, a first infinite gain multi-path feedback low-pass filter connected to the IV conversion circuit, a high-pass filtering module connected to the first infinite gain multi-path feedback low-pass filter, a second infinite gain multi-path feedback low-pass filter connected to the high-pass filtering module, a negative feedback amplifying and rectifying module connected to the second infinite gain multi-path feedback low-pass filter, a voltage follower connected to the negative feedback amplifying and rectifying module, and a protection circuit output end connected to the voltage follower.
The IV conversion circuit comprises a first amplifier, a first resistor and a first capacitor, wherein the photoelectric signal input end is connected with the inverting input end of the first amplifier, the forward input end of the first amplifier is grounded, the first resistor is connected with the inverting input end and the output end of the first amplifier in parallel, and the first capacitor is connected with the inverting input end and the output end of the first amplifier in parallel.
The first infinite gain multi-channel feedback low-pass filter comprises a second amplifier, a second resistor, a third resistor, a fourth capacitor and a fifth capacitor, the second resistor is connected with the output end of the first amplifier, one end of the third resistor is connected with the second resistor, the other end of the third resistor is connected with the reverse input end of the second amplifier, the fourth capacitor is connected with the forward input end of the second amplifier and one end, close to the third resistor, of the second resistor, the fourth resistor is connected with the output end of the second amplifier and one end, close to the third resistor, of the second resistor, and the fifth capacitor is connected with the reverse input end of the second amplifier and the output end of the second amplifier.
The high-pass filtering module comprises an eighth capacitor and a fifth resistor, one end of the eighth capacitor is connected with the output end of the second amplifier, and the other end of the eighth capacitor is connected with the fifth resistor.
The second infinite gain multi-path feedback low-pass filter comprises a third amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth capacitor and a tenth capacitor, one end of the sixth resistor is connected with the eighth capacitor, the other end of the sixth resistor is connected with the eighth resistor, the inverting input end of the third amplifier is connected with the eighth resistor, one end of the ninth capacitor is connected with one end of the sixth resistor close to the eighth resistor, the other end of the ninth capacitor is grounded, one end of the seventh resistor is connected with one end of the sixth resistor close to the eighth resistor, the other end of the seventh resistor is connected with the output end of the third amplifier, and the tenth capacitor is connected in parallel with the inverting input end and the output end of the third amplifier.
Wherein the negative feedback amplification rectification module comprises a fourth amplifier, an alternative analog switch, a ninth resistor, a tenth resistor, an eleventh resistor, a second diode and a third diode, the ninth resistor is connected with the output end of the third amplifier, the inverting input end of the fourth amplifier is connected with the ninth resistor, the anode of the second diode is connected with the reverse input end of the fourth amplifier, the cathode of the second diode is connected with the output end of the fourth amplifier, the anode of the third diode is connected with the output end of the fourth amplifier, the tenth resistor is connected with the cathode of the third diode, the eleventh resistor is connected with the cathode of the third diode, and the one-of-two analog switch is connected with the reverse input end of the fourth amplifier and is arranged on one side of the tenth resistor and one side of the eleventh resistor.
The voltage follower comprises a seventh amplifier, a twelfth resistor and an eleventh capacitor, wherein the twelfth resistor is connected with the cathode of the third diode, the forward input end of the seventh amplifier is connected with the twelfth resistor, and the reverse input end of the seventh amplifier is connected with the output end of the seventh amplifier.
Wherein, the output end of the protection circuit comprises a voltage stabilizing source, an eighth amplifier, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a first triode, a second triode and a fourteenth capacitor, the nineteenth resistor is connected with the output end of the seventh amplifier, the emitter of the second triode is connected with the nineteenth resistor, the collector of the second triode is grounded, the base of the second triode is connected with the eighteenth resistor, the output end of the eighth amplifier is connected with the eighteenth resistor, the emitter of the first triode is connected with the reverse input end of the eighth amplifier, the collector of the first triode is grounded, one end of the seventeenth resistor is connected with the base of the first triode, the other end of the seventeenth resistor is connected with the output end of the eighth amplifier, one end of the sixteenth resistor is connected with the reverse input end of the eighth amplifier, the other end of the sixteenth resistor is connected with the power supply end of the eighth amplifier, one end of the thirteenth resistor is connected with the power supply end of the eighth amplifier, the other end of the thirteenth resistor is connected with the forward input end of the eighth amplifier, the fourteenth resistor is connected with the thirteenth resistor, one end of the fifteenth resistor is connected with the fourteenth resistor, the other end of the fifteenth resistor is grounded, one end of the fourteenth capacitor is connected with the forward input end of the eighth amplifier, the other end of the fourteenth capacitor is grounded, and the voltage stabilizing source is arranged at two ends of the fourteenth resistor and the fifteenth resistor.
The utility model relates to a weak signal amplification shaping circuit applied to a blood analyzer, in the blood analyzer, an optical channel needs to amplify and acquire three angle signals of sheath flow (S1, S2 and S3), and because three signals belong to different angles, the respective amplification factor is adjusted according to actual needs, and only one channel is described here. Specifically, we need to process the signal with a center frequency of 120Khz and a bandwidth of 100 Khz. The photosensor inputs a signal at the level of current nA. A photoelectric sensor in the blood analyzer generates current after being irradiated by light, and the current I is input from a photoelectric signal input ends_inThe first infinite gain multi-path feedback low-pass filter is used for amplifying the front-stage signal and filtering out the unwanted high-frequency interference signal. The high-pass filter functions to filter out low-frequency noise interference. The second infinite gain multi-path feedback low-pass filter is used for amplifying the front-stage signal and filtering out the unnecessary high-frequency interference signal. The negative feedback amplification rectification module can amplify signals and can also shape waveforms. Meanwhile, the channel can be switched to be suitable for different amplification gains, the voltage follower can prevent waveform overshoot or self-oscillation of the amplification circuit in actual use, the output end of the protection circuit can adjust threshold voltage, and therefore the protection circuit has the functions of a band-pass filter and noise reduction, meanwhile, the protection output circuit is provided, protection voltage is set, weak pulse signals can be extracted and amplified, and the anti-interference capability is strong.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a block diagram of a weak signal amplifying and shaping circuit used in a blood analyzer according to the present invention;
FIG. 2 is a detailed circuit diagram of a weak signal amplifying and shaping circuit for use in a blood analyzer according to the present invention;
FIG. 3 is a block diagram of the IV conversion circuit of the present invention;
FIG. 4 is a block diagram of a first infinite gain multi-feedback low pass filter;
FIG. 5 is a block diagram of a high pass filtering module;
FIG. 6 is a block diagram of a second infinite gain multi-feedback low pass filter;
FIG. 7 is a block diagram of a negative feedback amplification rectification module;
FIG. 8 is a block diagram of a voltage follower;
FIG. 9 is a block diagram of the output of the protection circuit;
FIG. 10 is a schematic diagram of waveform shaping;
fig. 11 is a pulse diagram of the present invention.
1-photoelectric signal input end, 2-IV conversion circuit, 3-first infinite gain multi-way feedback low-pass filter, 4-high-pass filter module, 5-second infinite gain multi-way feedback low-pass filter, 6-negative feedback amplification rectification module, 7-voltage follower, 8-protection circuit output end, U1-A-first amplifier, R1-first resistor, C1-first capacitor, U2-A-second amplifier, R2-second resistor, R3-third resistor, R4-fourth resistor, C4-fourth capacitor, C5-fifth capacitor, U2-B-third amplifier, R6-sixth resistor, R7-seventh resistor, R8-eighth resistor, C9-ninth capacitor, C10-tenth capacitor, U4-B-fourth amplifier, U3-B-alternative analog switch, R9-ninth resistor, R10-tenth resistor, R11 eleventh resistor, D2 second diode, D3-third diode, U4-A-seventh amplifier, R12-twelfth resistor, U5-voltage regulator, U6-A-eighth amplifier, R13-thirteenth resistor, R14-fourteenth resistor, R15-fifteenth resistor, R16-sixteenth resistor, R17-seventeenth resistor, R18-eighteenth resistor, R19-nineteenth resistor, Q1-first triode, Q2-second triode, C8-eighth capacitor and R5-fifth resistor.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the utility model and are not to be construed as limiting the utility model.
Referring to fig. 1 to 9, the present invention provides a weak signal amplifying and shaping circuit for use in a blood analyzer:
the device comprises a photoelectric signal input end 1, an IV conversion circuit 2 connected with the photoelectric signal input end 1, a first infinite gain multi-path feedback low-pass filter 3 connected with the IV conversion circuit 2, a high-pass filtering module 4 connected with the first infinite gain multi-path feedback low-pass filter 3, a second infinite gain multi-path feedback low-pass filter 5 connected with the high-pass filtering module 4, a negative feedback amplification rectifying module 6 connected with the second infinite gain multi-path feedback low-pass filter 5, a voltage follower 7 connected with the negative feedback amplification rectifying module 6, and a protection circuit output end 8 connected with the voltage follower 7.
In this embodiment, in the blood analyzer, the optical channel needs to amplify and acquire three angle signals of the sheath flow (S1, S2, S3), and since the three signals belong to different angles, the respective amplification factors are adjusted according to actual needs, and only one of the channels is described here. Specifically, we need to process the signal with a center frequency of 120Khz and a bandwidth of 100 Khz. The photosensor inputs a signal at the level of current nA.
A photoelectric sensor in the blood analyzer can generate current after being irradiated by light, and the current I is input from a photoelectric signal input end 1s_inThe first agc multipass low pass filter 3 is used to amplify the preceding stage signal and filter out unwanted high frequency interference signals. The high-pass filter functions to filter out low-frequency noise interference. The second infinite gain multi-path feedback low-pass filter 5 is used for amplifying the front-stage signal and filtering out the unwanted high-frequency interference signal. The negative feedback amplification rectification module 6 canFor signal amplification and also for shaping the waveform. Meanwhile, channels can be switched to be suitable for different amplification gains, the voltage follower 7 can prevent waveform overshoot or self-oscillation of an amplification circuit in actual use, the output end 8 of the protection circuit can adjust threshold voltage, and therefore the protection circuit has the functions of a band-pass filter and noise reduction, meanwhile, the protection output circuit is provided, protection voltage is set, weak pulse signals can be extracted and amplified, and the anti-interference capability is high.
Further, the IV conversion circuit 2 includes a first amplifier U1-a, a first resistor R1, and a first capacitor C1, the optical signal input terminal 1 is connected to the inverting input terminal of the first amplifier U1-a, the forward input terminal of the first amplifier U1-a is grounded, the first resistor R1 is connected in parallel to the inverting input terminal and the output terminal of the first amplifier U1-a, and the first capacitor C1 is connected in parallel to the inverting input terminal and the output terminal of the first amplifier U1-a.
In the present embodiment, the output voltage U ═ Is_inR1. The capacitor C1 has a phase advancing function, and in the basic circuit of I-V conversion, since the phase is delayed by the input parasitic capacitance, the circuit is likely to oscillate, and therefore phase compensation is required.
Further, the first infinite gain multi-feedback low-pass filter 3 includes a second amplifier U2-a, a second resistor R2, a third resistor R3, a fourth resistor R4, a fourth capacitor C4, and a fifth capacitor C5, the second resistor R2 is connected to the output terminal of the first amplifier U1-a, one end of the third resistor R3 is connected to the second resistor R2, the other end of the third resistor R3 is connected to the inverting input terminal of the second amplifier U2-a, the fourth capacitor C4 is connected to the forward input terminal of the second amplifier U2-a and one end of the second resistor R2 near the third resistor R3, the fourth resistor R4 is connected to the output terminal of the second amplifier U2-a and one end of the second resistor R2 near the third resistor R3, and the fifth capacitor C5 is connected to the inverting input terminal of the second amplifier U2-a and the inverting input terminal of the second amplifier U2-a.
In this embodiment, the module is used to forward the preceding stage signalThe line is amplified and unwanted high frequency interference signals are filtered out, and the gain G1 is-R4/R2. Natural angular frequency
Low pass filter cut-off frequency
Further, the high-pass filtering module 4 includes an eighth capacitor C8 and a fifth resistor R5, one end of the eighth capacitor C8 is connected to the output end of the second amplifier U2-a, and the other end of the eighth capacitor C8 is connected to the fifth resistor R5.
In the present embodiment, the cut-off frequency
The module functions to filter out low frequency noise interference.
Further, the second infinite gain multi-feedback low pass filter 5 comprises a third amplifier U2-B, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth capacitor C9 and a tenth capacitor C10, one end of the sixth resistor R6 is connected to the eighth capacitor C8, the other end of the sixth resistor R6 is connected to the eighth resistor R8, the inverting input terminal of the third amplifier U2-B is connected to the eighth resistor R8, one end of the ninth capacitor C9 is connected to one end of the sixth resistor R6 near the eighth resistor R8, the other end of the ninth capacitor C9 is grounded, one end of the seventh resistor R7 is connected to one end of the sixth resistor R6 close to the eighth resistor R8, the other end of the seventh resistor R7 is connected with the output end of the third amplifier U2-B, the tenth capacitor C10 is connected in parallel to the inverting input and output of the third amplifier U2-B.
In the present embodiment, the second infinite gain multi-feedback low-pass filter 5 is used to amplify a previous-stage signal and filter out an unnecessary high-frequency interference signal. Gain G2 ═ R7/R6. Natural angular frequency
Low pass filter cut-off frequency
The module and the high-pass filtering of the previous module are combined to form a band-pass filter circuit, and the band-pass filter circuit plays a role in inhibiting signals except for the frequencies from f1 to f 2.
Further, the negative feedback amplification rectification module 6 comprises a fourth amplifier U4-B, an alternative analog switch U3-B, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a second diode D2 and a third diode D3, the ninth resistor R9 is connected with the output end of the third amplifier U2-B, the reverse input end of the fourth amplifier U4-B is connected with the ninth resistor R9, the anode of the second diode D2 is connected with the reverse input end of the fourth amplifier U4-B, the cathode of the second diode D2 is connected with the output end of the fourth amplifier U4-B, the anode of the third diode D3 is connected with the output end of the fourth amplifier U4-B, the tenth resistor R10 is connected with the cathode of the third diode D3, the eleventh resistor R11 is connected with the cathode of the third diode D3, the one-out-of-two analog switch U3-B is connected with the inverting input terminal of the fourth amplifier U4-B and is arranged at one side of the tenth resistor R10 and the eleventh resistor R11.
In this embodiment, since in a blood cell analyzer, the white blood cells and the reticulocytes are often shared by the same channel for cost saving, but the optical signal received by measuring the reticulocytes is much weaker than that of the white blood cells, which makes it difficult to find a midpoint, for example, by amplifying the collected signal by a transamplifier so that the system can recognize that the reticulocyte signal is weakly adjusted to an appropriate magnitude, but the signal amplification is too large for the white blood cells, and too small for the reticulocyte signal if the white blood cell signal is adjusted to an appropriate magnitude. So here an alternative analogue switch U3-B is used, switching according to the need of the measurement signal. The gain G3 ═ R10/R9 or G3 ═ R11/R9. The combination of diodes D2 and D3 achieves waveform rectification, so this module needs to shape the waveform in addition to amplifying the signal. However, the module does not perform filtering processing any more, because the feedback resistance is inconsistent, when the filtering frequency is adjusted, another channel is switched to cause the filtering parameter to change. As shown in fig. 10, in the positive half cycle (time 0 to t 1) of the input signal, D2 is turned on, D3 is turned off, and the circuit is equivalent to a voltage follower 7: before the D2 and the D3 are conducted, the circuit is in an open loop state with a maximum voltage amplification factor, at the moment (in the positive half-wave input period of the input signal), even if the input end of the amplifier becomes negative due to a tiny input signal, the diode D2 is conducted in a forward bias mode (equivalent to short circuit), the D3 is cut off in a reverse bias mode (equivalent to open circuit), a voltage follower 7 mode is formed, and the output end can still keep zero potential because the in-phase end is grounded and the circuit becomes a voltage follower 7 following the ground level. In the negative half cycle of the input signal (time t 1-t 2), D2 is turned off, D3 is turned on, and the circuit is equivalent to an inverter. During the negative half-wave of the input signal, even if the output terminal of the minute input signal becomes positive (before the conduction of D2 and D3), the diode D2 is reversely biased to be turned off, and the D3 is positively biased to be turned on, so that the circuit mode of the inverter (amplifier) is formed, and the negative half-wave signal is subjected to inverted output.
Further, the voltage follower 7 comprises a seventh amplifier U4-A and a twelfth resistor R12, the twelfth resistor R12 is connected with the cathode of the third diode D3, the forward input end of the seventh amplifier U4-A is connected with the twelfth resistor R12, and the reverse input end of the seventh amplifier U4-A is connected with the output end of the seventh amplifier U4-A.
In this embodiment, the output impedance of the voltage amplifier is generally high, usually from several kilohms to several tens of kilohms, and if the input impedance of the subsequent stage is relatively low, a considerable portion of the signal is lost in the output resistor of the previous stage. At this time, the voltage follower 7 is required to buffer therefrom. Play the role of starting and stopping. The twelfth resistor R12 and the eleventh capacitor C11 reserve functions. The waveform overshoot or the self-oscillation of the amplifying circuit in actual use is prevented, and a corresponding value or a blank patch can be set according to the actual use condition.
Further, the output end 8 of the protection circuit includes a voltage regulator U5, an eighth amplifier U6-a, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a first triode Q1, a second triode Q2, and a fourteenth capacitor C14, the nineteenth resistor R19 is connected to the output end of the seventh amplifier U4-a, the emitter of the second triode Q2 is connected to the nineteenth resistor R19, the collector of the second triode Q2 is grounded, the base of the second triode Q2 is connected to the eighteenth resistor R18, the output end of the eighth amplifier U6-a is connected to the eighteenth resistor R18, the emitter of the first triode Q1 is connected to the input end of the eighth U6-a, the collector of the first triode Q1 is grounded, one end of the seventeenth resistor R17 is connected to the base of the first triode Q1, the other end of the seventeenth resistor R17 is connected to the output terminal of the eighth amplifier U6-a, one end of the sixteenth resistor R16 is connected to the inverting input terminal of the eighth amplifier U6-a, the other end of the sixteenth resistor R16 is connected to the power supply terminal of the eighth amplifier U6-a, one end of the thirteenth resistor R13 is connected to the power supply terminal of the eighth amplifier U6-a, the other end of the thirteenth resistor R13 is connected to the positive input terminal of the eighth amplifier U6-a, the fourteenth resistor R14 is connected to the thirteenth resistor R13, one end of the fifteenth resistor R15 is connected to the fourteenth resistor R14, the other end of the fifteenth resistor R15 is grounded, and one end of the fourteenth capacitor is connected to the positive input terminal of the eighth amplifier U6-a, the other end of the fourteenth capacitor is grounded, and the voltage regulator U5 is disposed across the fourteenth resistor R14 and the fifteenth resistor R15.
In this embodiment, the desired threshold voltage V can be obtained by the proportional relationship between the regulator U5 and the fourteenth resistor R14 and the fifteenth resistor R15 according to different valueslinit. The calculation formula is as follows: vlimit＝Vref(1+R14/R15)+IrefR14, wherein VrefAnd IrefCan be obtained by consulting the chip data manual. The specific principle is that the positive end input voltage of the eighth amplifier U6-A is VlimitThen under the feedback action, the input angular voltage at the negative terminal will also reach VlimitAt this time, the output of the operational amplifier is also VlimitOtherwise, current flows through the seventeenth resistor R17, and the whole circuit is not balanced. Suppose the output voltage is Vs_out. When V iss_out>VlimitWhen the voltage of the second triode Q2 is reduced to zero, the second triode Q2 is turned off again, the voltage rises, and finally, the voltage reaches V when the balance is reacheds_out＝VlimitThus, the protection of the circuit at the later stage is achieved, such as the three pulse signals of FIG. 11, when the signal is greater than VlimitWill be clamped at Vlimit。
As shown in FIG. 11, the amplitude of the 4 pulses at time T, i.e., the pulse signals at times T3-T4 and T5-T6, exceeds Vlimit，So as to be limited at VlimitThe back-end circuit is protected.
While the utility model has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the utility model.
Claims (8)
1. A weak signal amplifying and shaping circuit applied to a blood analyzer, which is characterized in that,
the high-pass filter circuit comprises a photoelectric signal input end, an IV conversion circuit connected with the photoelectric signal input end, a first infinite gain multi-path feedback low-pass filter connected with the IV conversion circuit, a high-pass filter module connected with the first infinite gain multi-path feedback low-pass filter, a second infinite gain multi-path feedback low-pass filter connected with the high-pass filter module, a negative feedback amplification rectification module connected with the second infinite gain multi-path feedback low-pass filter, a voltage follower connected with the negative feedback amplification rectification module, and a protection circuit output end connected with the voltage follower.
2. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 1,
the IV conversion circuit comprises a first amplifier, a first resistor and a first capacitor, wherein the photoelectric signal input end is connected with the reverse input end of the first amplifier, the forward input end of the first amplifier is grounded, the first resistor is connected with the reverse input end and the output end of the first amplifier in parallel, and the first capacitor is connected with the reverse input end and the output end of the first amplifier in parallel.
3. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 2,
the first infinite gain multi-channel feedback low-pass filter comprises a second amplifier, a second resistor, a third resistor, a fourth capacitor and a fifth capacitor, the second resistor is connected with the output end of the first amplifier, one end of the third resistor is connected with the second resistor, the other end of the third resistor is connected with the reverse input end of the second amplifier, the fourth capacitor is connected with the forward input end of the second amplifier and one end, close to the third resistor, of the second resistor, the fourth resistor is connected with the output end of the second amplifier and one end, close to the third resistor, of the second resistor, and the fifth capacitor is connected with the reverse input end of the second amplifier and the output end of the second amplifier.
4. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 3,
the high-pass filtering module comprises an eighth capacitor and a fifth resistor, one end of the eighth capacitor is connected with the output end of the second amplifier, and the other end of the eighth capacitor is connected with the fifth resistor.
5. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 4,
the second infinite gain multi-path feedback low-pass filter comprises a third amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth capacitor and a tenth capacitor, one end of the sixth resistor is connected with the eighth capacitor, the other end of the sixth resistor is connected with the eighth resistor, the reverse input end of the third amplifier is connected with the eighth resistor, one end of the ninth capacitor is connected with one end, close to the eighth resistor, of the sixth resistor, the other end of the ninth capacitor is grounded, one end of the seventh resistor is connected with one end, close to the eighth resistor, of the sixth resistor, the other end of the seventh resistor is connected with the output end of the third amplifier, and the tenth capacitor is connected in parallel with the reverse input end and the output end of the third amplifier.
6. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 5,
the negative feedback amplification rectification module comprises a fourth amplifier, an alternative analog switch, a ninth resistor, a tenth resistor, an eleventh resistor, a second diode and a third diode, the ninth resistor is connected with the output end of the third amplifier, the inverting input end of the fourth amplifier is connected with the ninth resistor, the anode of the second diode is connected with the reverse input end of the fourth amplifier, the cathode of the second diode is connected with the output end of the fourth amplifier, the anode of the third diode is connected with the output end of the fourth amplifier, the tenth resistor is connected with the cathode of the third diode, the eleventh resistor is connected with the cathode of the third diode, and the one-of-two analog switch is connected with the reverse input end of the fourth amplifier and is arranged on one side of the tenth resistor and one side of the eleventh resistor.
7. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 6,
the voltage follower comprises a seventh amplifier, a twelfth resistor and an eleventh capacitor, wherein the twelfth resistor is connected with the cathode of the third diode, the forward input end of the seventh amplifier is connected with the twelfth resistor, and the reverse input end of the seventh amplifier is connected with the output end of the seventh amplifier.
8. The weak signal amplifying and shaping circuit for use in a blood analyzer according to claim 7,
the output end of the protection circuit comprises a voltage stabilizing source, an eighth amplifier, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a first triode, a second triode and a fourteenth capacitor, the nineteenth resistor is connected with the output end of the seventh amplifier, the emitter of the second triode is connected with the nineteenth resistor, the collector of the second triode is grounded, the base of the second triode is connected with the eighteenth resistor, the output end of the eighth amplifier is connected with the eighteenth resistor, the emitter of the first triode is connected with the reverse input end of the eighth amplifier, the collector of the first triode is grounded, one end of the seventeenth resistor is connected with the base of the first triode, and the other end of the seventeenth resistor is connected with the output end of the eighth amplifier, one end of the sixteenth resistor is connected with the reverse input end of the eighth amplifier, the other end of the sixteenth resistor is connected with the power supply end of the eighth amplifier, one end of the thirteenth resistor is connected with the power supply end of the eighth amplifier, the other end of the thirteenth resistor is connected with the forward input end of the eighth amplifier, the fourteenth resistor is connected with the thirteenth resistor, one end of the fifteenth resistor is connected with the fourteenth resistor, the other end of the fifteenth resistor is grounded, one end of the fourteenth capacitor is connected with the forward input end of the eighth amplifier, the other end of the fourteenth capacitor is grounded, and the voltage stabilizing source is arranged at two ends of the fourteenth resistor and the fifteenth resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121765196.5U CN215773056U (en) | 2021-07-30 | 2021-07-30 | Weak signal amplification shaping circuit applied to blood analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202121765196.5U CN215773056U (en) | 2021-07-30 | 2021-07-30 | Weak signal amplification shaping circuit applied to blood analyzer |
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