High-precision constant current source for biochip detection

Abstract

The invention discloses a high-precision constant current source for biochip detection, and belongs to the technical field of bioelectronics and precision measurement. The constant current source can provide stable and accurate 1muA-level current output in a complex biochip environment. The circuit has the main technical characteristics of high-precision output, high stability, easiness in integration and intelligent control, and adopts an advanced current control technology to ensure that the current output precision of 1 mu A is realized, so that the requirement of accurate source supply for weak current signals in biochip detection is met. The unique temperature compensation and noise suppression technology ensures that the constant current source can still maintain the stability of the output current in a complex environment.

Description

Technical Field

[0001] The invention relates to a high-precision constant current source for biochip detection, in particular to a solution for 1μA current detection of biomolecules. Background Art

[0002] In the biochip electrochemical embedded detection system, the current intensity to be detected is generally 10e -9 To 10e -3 A, which belongs to the range of weak current signals. Since the current signals generated by the interactions and reactions between biomolecules are often very weak, it is necessary to use detection technology that can accurately measure these weak current signals.

[0003] At present, the various micro-current power supply devices on the market still have obvious shortcomings in meeting the high-precision and high-stability requirements of biochip technology. The accuracy of current output of these devices is often difficult to reach the 1μA level, which cannot meet the precise supply requirements of weak current signals in biomolecule detection. In complex environments, such as temperature fluctuations and electromagnetic interference, the stability of these devices is poor, which may cause current output fluctuations, thereby affecting the accuracy of biochip detection. In addition, the technical limitations that may exist in the design and manufacturing of these devices also limit their widespread application in biochip technology.

[0004] Compared with the existing micro-current power supply devices on the market, high-precision constant current sources show significant advantages in biochip technology. High-precision constant current sources can achieve current output accuracy of up to 1μA, meeting the precise supply requirements for weak current signals in biochip detection. Through unique temperature compensation and noise suppression technology, high-precision constant current sources can maintain the stability of output current in complex environments and ensure the accuracy of biochip detection. In addition, high-precision constant current sources also have the characteristics of easy integration and intelligent control, which can achieve seamless docking with biochip technology and improve detection efficiency. Therefore, the development of a high-precision constant current source for biochip detection has become an urgent need for current technological development. Summary of the invention

[0005] The purpose of the present invention is to provide a high-precision constant current source for biochip detection.

[0006] The object of the present invention is achieved in that:

[0007] The high-precision constant current source for biochip detection can make the current signal generated on the biochip stable and measurable by precisely controlling the output of the current;

[0008] In the field of biochip detection, the current signal is a key indicator of the interaction between biomolecules. Its precision and stability are crucial to the accuracy of the results, especially when it comes to weak current detection at the 1μA level. Any slight current fluctuation may lead to deviations in the detection results.

[0009] During the biochip detection process, the constant current source not only needs to accurately adjust the output current according to the preset current value, but also needs to maintain a stable output throughout the detection process to cope with changes in various environmental factors and operating conditions;

[0010] The power conversion module provides two output channels, positive and negative. The output voltage of each channel is not regulated, that is, the output voltage may fluctuate with factors such as input voltage and load changes;

[0011] The input voltage is first converted into high-frequency AC, then converted into voltage through a transformer, and finally converted into the required DC voltage output through a rectifier circuit;

[0012] The module contains complex control circuits to monitor and adjust the output voltage;

[0013] Although the A1205S-1WR3 has an unregulated output, the control circuit still monitors the output voltage to a certain extent to ensure that it fluctuates within an acceptable range.

[0014] In order to protect the module from abnormal conditions such as overload and short circuit, the A1205S-1WR3 usually integrates multiple protection mechanisms (overcurrent protection, overvoltage protection and short circuit protection). When an abnormal condition is detected, the protection mechanism quickly cuts off the output to prevent damage to the module;

[0015] The module is mainly composed of transformer, rectifier diode, filter capacitor, control chip and other components;

[0016] The transformer is responsible for voltage conversion; the rectifier diode converts AC into DC; the filter capacitor is used to smooth the output voltage; the control chip is responsible for monitoring and adjusting the output voltage, as well as implementing the protection mechanism.

[0017] Since the current signal generated on the biochip is very weak, a special current amplifier is needed to amplify the signal, and precision resistors are used to convert the current signal into a voltage signal for subsequent processing and analysis.

[0018] The operational amplifier in the high-precision constant current source for biochip detection adopts OPA602AP, an integrated circuit containing a multi-stage amplification circuit, mainly including an input stage, an intermediate stage, an output stage and a bias circuit. These four circuits work together to achieve a high amplification factor, low noise and high-precision signal amplification function;

[0019] The input stage uses a differential amplifier circuit, using dielectric isolation FET Technology significantly reduces input bias current. The differential amplifier circuit has a strong zero drift suppression capability, which can effectively reduce output drift caused by factors such as temperature changes. The input bias current is extremely low, only 2pA, which helps to improve the accuracy and stability of the overall circuit.

[0020] The intermediate stage uses a common-emitter amplifier circuit to further amplify the input signal. The intermediate stage is designed to provide sufficient gain while maintaining low noise and distortion;

[0021] The output stage uses a power amplifier circuit with strong load capacity to ensure that the output signal can drive various loads. The output impedance of the bias circuit is close to zero, making the output signal insensitive to load changes, improving the stability and reliability of the circuit, and providing the necessary operating voltage for each level of amplifier circuits to ensure that the circuit can work normally.

[0022] The current REF200AU, a high-precision constant current source used for biochip detection, integrates two independent 100μA high-precision current sources. The initial accuracy of each current source is as high as ±0.5% and the temperature drift is extremely small, only ±25ppm / ℃;

[0023] A 100μA current source is copied to a new branch through current mirroring technology, and one or more attenuation resistors are connected in series to the branch, so that the current passing through the branch is reduced to 1μA.

[0024] In the high-precision constant current source circuit for biochip detection, temperature changes can affect the performance of electronic components, and the high-precision constant current source uses temperature compensation technology to eliminate the influence of temperature on current output.

[0025] In the biochip detection, environmental noise and circuit noise may interfere with tiny current signals. The high-precision constant current source adopts low-noise circuit design and electromagnetic shielding, and reduces the impact of noise on detection results by optimizing circuit layout, selecting low-noise components and using filtering technology.

[0026] The high-precision constant current source for biochip detection introduces a negative feedback mechanism to monitor the output current in real time and compare it with a preset reference current;

[0027] When the output current deviates from the preset value due to changes in load impedance or other external interference, the negative feedback circuit will automatically adjust the circuit parameters (such as the output voltage of the operational amplifier or the driving voltage of the current source) to reduce the deviation between the output current and the reference current, thereby keeping the output current constant.

[0028] The high-precision constant current source for biochip detection optimizes the design of the load matching network and reduces the impact of load impedance changes on the output current.

[0029] Working principle: Based on precise control of power supply voltage and resistance value to ensure constant current output. In a constant current source, the power supply provides a stable voltage, while the resistor is used to limit the flow of current. By designing and adjusting the relationship between the power supply voltage and the resistance value, an accurate 1μA current output can be achieved. A precise current control circuit is adopted. By introducing a high-precision feedback circuit and a stable reference voltage source, the current output can be monitored and adjusted in real time to ensure that it remains stable near the set value.

[0030] The beneficial effects produced by the present invention are:

[0031] 1. A high-precision constant current source for biochip detection greatly improves the application performance of biochips in biomedicine, drug development, gene sequencing and other fields by providing stable, accurate and reliable 1μA current output.

[0032] 2. Its high-precision current output ensures the accuracy and reliability of the experimental results, while its good stability and reliability ensure long-term, continuous and stable current supply.

[0033] 3. The low-power design extends the use time of the biochip and reduces energy consumption, while functions such as overvoltage, overcurrent and short-circuit protection effectively protect the safety of circuits and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0035] Figure 1 It is a system flow chart of the present invention.

[0036] Figure 2 It is a power conversion design circuit diagram of the present invention.

[0037] Figure 3 It is the current source design circuit diagram of the present invention. DETAILED DESCRIPTION

[0038] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0039] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual drawings, and should not be understood as limitations of this patent.

[0040] The power module model is A1205S-1WR3, which is used for voltage conversion;

[0041] The current source module model is REF200AU, which is used to stably output 100μA current;

[0042] The precision operational amplifier module model is OPA602P, which is used for precise current control;

[0043] like Figure 1 As shown, in the high-precision constant current source for biochip detection, the power conversion converts the 12V DC power supply into a ±5V voltage;

[0044] The current source design uses an operational amplifier as a core component to stably output 1μA current;

[0045] After the current source design, the circuit obtains a stable 1μA current output, which is supplied to the biochip for detection;

[0046] To ensure the constancy and accuracy of the output current, the high-precision constant current source monitors the output current in real time through current sampling and compares it with the preset current value;

[0047] like Figure 2 As shown, the power conversion circuit in the high-precision constant current source for biochip detection converts the input 12V power supply into a stable voltage of ±5V;

[0048] The power conversion circuit is added with a filter circuit to reduce noise interference and ensure the stability and accuracy of the output voltage;

[0049] The power conversion circuit includes: a capacitor C1, a tantalum capacitor C2, a tantalum capacitor C3, a resistor R1, a resistor R2, a resistor R3, an inductor L1, an inductor L2, an inductor L3, a light emitting diode LED1 and a power module A1205S-1WR3;

[0050] The power conversion circuit connects the positive electrode of the 12V DC power supply to the positive input terminal (VIN) of the A1205S-1WR3, and connects the negative electrode of the 12V DC power supply to the negative input terminal (GND) of the A1205S-1WR3;

[0051] The nominal input voltage of the power module is 12V, and the range is between 10.8 and 13.2V;

[0052] The power module A1205S-1WR3 has positive and negative dual-channel output capability and can output a ±5V DC voltage;

[0053] The resistor R1 in the power conversion circuit serves as a current limiting resistor of the light emitting diode LED1, and the capacitor C1 and the inductor L1 form a filter;

[0054] The power conversion circuit is connected to a capacitor filter network at the input and output ends to reduce input and output ripples;

[0055] In the power conversion circuit, in order to avoid the output load being used without load, when the actual power consumption of the load is less than 10% of the rated output power of the module or there is a no-load phenomenon, a dummy load is connected to the output end, and the dummy load (resistance) is calculated according to 5-10% of the rated power of the module;

[0056] Resistance value = U out / (1WR3*10%);

[0057] like Figure 3 As shown, the high-precision constant current source circuit in the high-precision constant current source for biochip detection stably outputs 100μA current to the current feedback control circuit based on the precision operational amplifier;

[0058] The high-precision constant current source circuit comprises: a current source REF200AU, a capacitor C5 and a Schottky diode D1;

[0059] The capacitor C5 in the high-precision constant current source circuit performs circuit filtering, and the Schottky diode D1 is responsible for circuit protection;

[0060] The current feedback control circuit based on a precision operational amplifier in a high-precision constant current source for biochip detection comprises: a precision operational amplifier OPA602P, a resistor R4, a resistor R5 and a capacitor C4;

[0061] After receiving the 100 μA current output by the high-precision constant current source circuit, the current feedback control circuit based on the precision operational amplifier adds resistors R4 and R5 of specific resistance values ​​for calculation and outputs a 1 μA current;

[0062] The process equation of the current feedback control circuit based on the precision operational amplifier converting the 100μA current output by the current source into a 1μA current is:

[0063] I out =100×(R4 / R5).

Claims

1. A high-precision constant current source for biochip detection, characterized in that: It consists of a power conversion circuit, a current source circuit and a current output circuit. In the circuit: 1) the electrical isolation between the input and the output is achieved by an isolation DC / DC converter to prevent the current from flowing directly between the input and the output; 2) the current source design uses an operational amplifier as a core component for stable output of 1μA current; 3) after the circuit is designed with the above current source, a stable 1μA current output is obtained, which is used to supply the biochip for detection; 4) the high-precision constant current source monitors the output current in real time through current sampling to ensure the constancy and accuracy of the output current, which is used for comparison with the preset current value.

2. A high-precision constant current source for biochip detection according to claim 1, characterized in that: The current source design adopts advanced current control technology to reduce the fluctuation and noise of the output current and achieve a current output accuracy of 1μA level.

3. The high-precision constant current source for a biochip according to claim 1, characterized in that: The constant current source also includes an integrated and modular design, which is easy to integrate with the biochip system.

4. A high-precision constant current source for a biochip according to claim 2, characterized in that: The high-precision constant current source has a low power consumption design and is suitable for long-term operation and battery-powered application scenarios.

5. A high-precision constant current source for biochip detection according to any one of the above claims, characterized in that: The high-precision constant current source meets the requirement for accurate measurement of weak current signals in biochip detection.

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