CN212013138U

CN212013138U - Low-noise high-dynamic-range photoelectric conversion device

Info

Publication number: CN212013138U
Application number: CN202020103362.4U
Authority: CN
Inventors: 董峰; 赵大隆
Original assignee: Zhongsheng Suzhou Medical Technology Co ltd
Current assignee: Zhongsheng Suzhou Medical Technology Co ltd
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2020-11-24
Anticipated expiration: 2030-01-17

Abstract

The utility model discloses a high dynamic range photoelectric conversion device of low noise sets up transimpedance amplifier circuit, difference amplifier circuit and output biasing regulating circuit, through adjustment output biasing circuit, enlarges the scope of useful signal, and the differential circuit of back level just will compress like this. The amplitude value output to the AD sampling circuit is ensured to be unchanged, so that the noise signal is attenuated, the dynamic range of the adjusted circuit signal is larger, and the signal-to-noise ratio is higher. The amplification ratio of the signal is improved, and if the direct current level of the original 4V output signal is translated to 2.5V, the range of the signal becomes 6.5V. The small signal can be identified, the large signal can not be saturated, and the dynamic range is improved.

Description

Low-noise high-dynamic-range photoelectric conversion device

Technical Field

The utility model belongs to the technical field of STREAMING photoelectric conversion electronic circuit, concretely relates to high dynamic range photoelectric conversion device of low noise.

Background

A Flow cytometer (Flow cytometer) is a device that automatically analyzes and sorts cells. It can quickly measure, store and display a series of important biophysical and biochemical characteristic parameters of dispersed cells suspended in liquid, and can select specified cell subsets according to the preselected parameter range. Most flow cytometers are zero resolution instruments that can only measure an index such as total nucleic acid, total protein, etc. of a cell, but cannot identify and measure the amount of nucleic acid or protein at a particular location. That is, its detail resolution is zero.

Flow cytometry consists essentially of four parts. They are: a flow chamber and a fluid flow system; a laser source and an optical system; a photoelectric tube and a detection system; a computer and an analysis system.

Photoelectric tube and detection system

The fluorescence generated by the fluorescence-stained cells after excitation with suitable light is measured by conversion into an electrical signal by a photoelectric converter. Photomultiplier tubes (PMTs) are most commonly used. The PMT has short response time which is only ns magnitude; the spectral response characteristic is good, and the light quantum yield is high in a spectral region of 200-900 nm. The gain of the photomultiplier tube is continuously adjustable from 10 to 10, and is therefore advantageous for low light measurements. During the operation of the photoelectric tube, the stability problem needs to be particularly noticed, the working voltage needs to be very stable, and the working current and the working power cannot be too large. The general power consumption is lower than 0.5W; the maximum anode current is at a few milliamps. In addition, attention is paid to dark adaptation processing of the photoelectric tube, and good magnetic shielding. In use, the PMTs are installed at different positions, which are not compatible with each other because of different spectral response characteristics. Also useful are silicon photodiodes, which are more stable than PMTs in high light.

The electrical signal output from the PMT is still weak and needs to be amplified before it can be input to the analytical instrument. Two types of amplifiers are typically provided in flow cytometry. One is that the output signal amplitude is linear with the input signal, called linear amplifier. Linear amplifiers are suitable for signals which vary over a relatively small range and also for signals which represent biological linear processes, such as DNA measurements, etc. The other is a logarithmic amplifier, with a common logarithmic relationship between the output signal and the input signal. Logarithmic amplifiers are often used in immunological measurements. Because three subgroups of negative, positive and strong positive are displayed simultaneously in immunoassay, the fluorescence intensity of the subgroups differs by 1-2 orders of magnitude; and in multicolor immunofluorescence measurement, the data collected by a logarithmic amplifier is easy to interpret. In addition, the method has the advantages of convenient adjustment, difficult influence of external working conditions on the distribution shape of cell populations and the like.

In the traditional flow type photoelectric conversion circuit, the voltage is not sufficiently utilized, the dynamic range of a circuit signal is smaller, and the signal-to-noise ratio is low.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome among the prior art STREAMING photoelectric conversion circuit voltage utilization not enough, circuit signal dynamic range is littleer, and the low not enough of SNR provides a high dynamic range photoelectric conversion device of low noise, and voltage utilization is rateed highly, and circuit signal dynamic range is bigger, and the SNR is higher.

In order to solve the problems in the prior art, the utility model discloses a low-noise high-dynamic range photoelectric conversion device, which comprises a transimpedance amplifier circuit, a differential amplifier circuit, an output bias regulator circuit and a sensor PD1, wherein the sensor PD1 is connected with the transimpedance amplifier circuit, the output bias regulator circuit is connected with the transimpedance amplifier circuit, the transimpedance amplifier circuit is connected with the differential amplifier circuit, the transimpedance amplifier circuit comprises a transimpedance amplifier U1, the differential amplifier circuit comprises a differential amplifier U2, the output bias regulator circuit comprises a resistor R10 and a resistor R11, the reverse input end of the transimpedance amplifier U1 is connected with the sensor PD1, one end of the resistor R10 is connected with a voltage input end, the other end of the resistor R10 is connected with the forward input end of the transimpedance amplifier U1, one end of the resistor R11 is connected with a resistor R10, the other end of the resistor is grounded, the output end of the transimpedance amplifier U1 is connected with the reverse input end of the differential amplifier U2, the positive input end of the differential amplifier U2 is grounded, and the output end of the differential amplifier U2 is connected with a voltage output end.

Further, the transimpedance amplifier circuit further includes a capacitor C1 and a resistor R1, one end of the resistor R1 is connected to the inverting input terminal of the transimpedance amplifier U1, the other end of the resistor R1 is connected to the output terminal of the transimpedance amplifier U1, and the capacitor C1 is connected to the resistor R1.

The differential amplifier circuit further includes a resistor R2, a resistor R3, a resistor R6, a resistor R7, a capacitor C2, and a capacitor C3, one end of the resistor R2 is connected to the output end of the transimpedance amplifier U1, the other end of the resistor R2 is connected to the inverting input end of the differential amplifier U2, one end of the resistor R3 is connected to the resistor R2, the other end of the resistor R3 is connected to the output end of the differential amplifier U2, one end of the resistor R7 is connected to the resistor R2 through the capacitor C2 and the capacitor C3, the other end of the resistor R7 is grounded, the capacitor C2 is grounded, the capacitor C3 is connected to the positive input end of the differential amplifier U2, one end of the resistor R6 is connected to the resistor R7, and the.

Further, the differential amplifier U2 includes two output terminals.

Further, the voltage regulator further comprises a resistor R8 and a resistor R9, and two output ends of the differential amplifier U2 are connected with a voltage output end through the resistor R8 and the resistor R9 respectively.

Furthermore, the capacitor comprises a capacitor C6 and a capacitor C7, wherein one end of the capacitor C6 is connected with the resistor R8, the other end of the capacitor C6 is grounded, one end of the capacitor C7 is connected with the resistor R9, and the other end of the capacitor C7 is grounded.

The utility model discloses beneficial effect who has:

the trans-impedance amplifying circuit, the differential amplifying circuit and the output bias adjusting circuit are arranged, the range of useful signals is expanded by adjusting the output bias circuit, and therefore the differential circuit at the later stage needs to be compressed. The amplitude value output to the AD sampling circuit is ensured to be unchanged, so that the noise signal is attenuated, the dynamic range of the adjusted circuit signal is larger, and the signal-to-noise ratio is higher.

Drawings

Fig. 1 is a schematic structural diagram of the present invention;

fig. 2 is a comparison graph of signal amplitude ranges before and after bias adjustment.

Reference numerals: the sensor PD1, the transimpedance amplifier U1, the differential amplifier U2, the resistor R1, the resistor R2, the resistor R3, the resistor R6, the resistor R7, the resistor R8, the resistor R9, the resistor R10, the resistor R11, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C6 and the capacitor C7.

Detailed Description

The present invention will be further described with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1, the low-noise high-dynamic-range photoelectric conversion device of the present invention includes a transimpedance amplifier circuit, a differential amplifier circuit, an output bias regulator circuit, and a sensor PD1, wherein the sensor PD1 is connected to the transimpedance amplifier circuit, the output bias regulator circuit is connected to the transimpedance amplifier circuit, the transimpedance amplifier circuit is connected to the differential amplifier circuit, the transimpedance amplifier circuit includes a transimpedance amplifier U1, the differential amplifier circuit includes a differential amplifier U2, the output bias regulator circuit includes a resistor R10 and a resistor R11, a reverse input terminal of the transimpedance amplifier U1 is connected to the sensor PD1, one end of the resistor R10 is connected to a voltage input terminal, the other end of the resistor R11 is connected to a forward input terminal of the transimpedance amplifier U1, one end of the resistor R11 is connected to a resistor R10, the other end of the resistor R1 is connected to a reverse input terminal of the differential amplifier U2, the positive input end of the differential amplifier U2 is grounded, and the output end of the differential amplifier U2 is connected with a voltage output end. The transimpedance amplifier circuit further comprises a capacitor C1 and a resistor R1, one end of the resistor R1 is connected with the reverse input end of the transimpedance amplifier U1, the other end of the resistor R1 is connected with the output end of the transimpedance amplifier U1, and the capacitor C1 is connected with the resistor R1. The differential amplification circuit further comprises a resistor R2, a resistor R3, a resistor R6, a resistor R7, a capacitor C2 and a capacitor C3, one end of the resistor R2 is connected with the output end of the transimpedance amplifier U1, the other end of the resistor R2 is connected with the reverse input end of the differential amplifier U2, one end of the resistor R3 is connected with a resistor R2, the other end of the resistor R3 is connected with the output end of the differential amplifier U2, one end of the resistor R7 is connected with the resistor R2 through the capacitor C2 and the capacitor C3, the other end of the resistor R7 is grounded, the capacitor C2 is grounded, the capacitor C3 is connected with the forward input end of the differential amplifier U2, one end of the resistor R6 is connected with the resistor R7. The differential amplifier U2 includes two outputs.

The utility model discloses a high dynamic range photoelectric conversion device of low noise still includes resistance R8 and resistance R9, two outputs of differential amplifier U2 pass through respectively resistance R8 with resistance R9 connects the voltage output end, still includes electric capacity C6 and electric capacity C7, electric capacity C6 one end is connected resistance R8, other end ground connection, electric capacity C7 one end is connected resistance R9, other end ground connection.

And the TIA trans-impedance amplifier U1 is adopted to convert the optical signal into an electrical signal, and the electrical signal is output to the AD through a single-ended to differential circuit. After light irradiates a PD1 sensor, current can be generated to flow through a resistor R1, the level of one end of the resistor R1 connected with an operational amplifier is 0 according to the principle of virtual short of the operational amplifier, so that the current flows through the resistor R1 and then outputs a voltage from 0 volt to a negative power supply rail at the output end of a transimpedance amplifier U1, if positive and negative 5 volts are adopted to supply power to the transimpedance amplifier U1, the output can generate a voltage signal from 0 to nearly 5 volts, and thus the other half of the positive voltage rail is not beneficial. Based on the above problem of outputting signals by using only one half of the power supply rails, in order to use the other half of the partial voltage, by adjusting the bias voltage of the non-inverting terminal of the transimpedance amplifier U1, as shown in fig. 1, the non-inverting terminal of the transimpedance amplifier U1 divides VCC by the resistor R10 and the resistor R11, and if VCC is 5V, the voltage division point level is 2.5V, which is extended by 2.5V compared with a circuit without bias. By adjusting the bias circuit, the range of the useful signal is expanded, as shown in fig. 2, so that the differential circuit of the subsequent stage is compressed. The amplitude value output to the AD sampling circuit is ensured to be unchanged, so that the noise signal is attenuated, the dynamic range of the adjusted circuit signal is larger, and the signal-to-noise ratio is higher. This is also an advantage and an object of the present invention. The amplification ratio of the signal is improved, and if the direct current level of the original 4V output signal is translated to 2.5V, the range of the signal becomes 6.5V. The small signal can be identified, the large signal can not be saturated, and the dynamic range is improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be considered as the protection scope of the present invention.

Claims

1. A low-noise high-dynamic-range photoelectric conversion device comprises a transimpedance amplification circuit, a differential amplification circuit, an output bias adjustment circuit and a sensor (PD 1), wherein the sensor (PD 1) is connected with the transimpedance amplification circuit, the output bias adjustment circuit is connected with the transimpedance amplification circuit, the transimpedance amplification circuit is connected with the differential amplification circuit, the transimpedance amplification circuit comprises a transimpedance amplifier (U1), the differential amplification circuit comprises a differential amplifier (U2), the output bias adjustment circuit comprises a resistor (R10) and a resistor (R11), the inverting input end of the transimpedance amplifier (U1) is connected with the sensor (PD 1), one end of the resistor (R10) is connected with a voltage input end, the other end of the resistor is connected with the forward input end of the transimpedance amplifier (U1), one end of the resistor (R11) is connected with a resistor (R10), the other end of the transimpedance amplifier (U1) is grounded, the output end of the transimpedance amplifier (U1) is connected with the inverting input end of the differential amplifier (U2), the positive input end of the differential amplifier (U2) is grounded, and the output end of the differential amplifier (U2) is connected with the voltage output end.

2. A low noise high dynamic range photoelectric conversion device according to claim 1, wherein said transimpedance amplification circuit further comprises a capacitor (C1) and a resistor (R1), said resistor (R1) is connected to the inverting input terminal of the transimpedance amplifier (U1) at one end, and is connected to the output terminal of the transimpedance amplifier (U1) at the other end, and said capacitor (C1) is connected to said resistor (R1).

3. A low noise high dynamic range photoelectric conversion apparatus according to claim 1, wherein the differential amplifier circuit further comprises a resistor (R2), a resistor (R3), a resistor (R6), a resistor (R7), a capacitor (C2) and a capacitor (C3), the resistor (R2) is connected to an output terminal of a transimpedance amplifier (U1) at one end and is connected to an inverting input terminal of the differential amplifier (U2) at the other end, the resistor (R3) is connected to the resistor (R2) at one end and is connected to an output terminal of the differential amplifier (U2) at the other end, the resistor (R7) is connected to the resistor (R2) through the capacitor (C2) and the capacitor (C3) at one end and is grounded at the other end, the capacitor (C2) is grounded, the capacitor (C3) is connected to an inverting input terminal of the differential amplifier (U2), the resistor (R6) is connected to the resistor (R7) at one end, the other end is connected with the output end of the differential amplifier (U2).

4. A low noise high dynamic range photoelectric conversion device according to claim 1, wherein said differential amplifier (U2) comprises two output terminals.

5. A low noise high dynamic range photoelectric conversion device according to claim 4, further comprising a resistor (R8) and a resistor (R9), wherein two output terminals of the differential amplifier (U2) are connected to the voltage output terminal through the resistor (R8) and the resistor (R9), respectively.

6. A low noise high dynamic range photoelectric conversion device according to claim 5, further comprising a capacitor (C6) and a capacitor (C7), wherein one end of the capacitor (C6) is connected to the resistor (R8), the other end is grounded, one end of the capacitor (C7) is connected to the resistor (R9), and the other end is grounded.