Potentiostat-based electrochemical sensor detection device and system including same

Abstract

Provided is a potentiostat-based electrochemical sensor detection device. The device comprises: a digital-to-analog converter (DAC) configured to receive a digital signal from a waveform generator and digital logic and output an analog signal corresponding to a reference voltage; a control amplifier (CA) configured to receive the analog signal corresponding to the reference voltage and apply the reference voltage to a reference electrode (RE); a gain-boosting current mirror configured to copy a sensor current of an electrochemical sensor and output a copied sensor current; a transimpedance amplifier configured to convert the copied sensor current into a voltage signal; a low-pass filter configured to block a high-frequency band signal component of the voltage signal; and an analog-to-digital converter (ADC) configured to perform digital signal processing on a signal having passed through the low-pass filter, wherein at least one of the gain-boosting current mirror and the transimpedance amplifier employs a dynamic element matching (DEM) technique using a plurality of choppers and a plurality of DEM clock signals.

Description

Potentiostat-based electrochemical sensor detection device and system including the same

[0001] The present invention relates to an electrochemical sensor detection device based on a potentiometer and a system including the same.

[0002] Since the COVID-19 pandemic, demand has grown significantly for diagnostic devices capable of rapid and accurate virus detection. Potentiostats, with their cost-effectiveness and portability, are widely used in clinical and research settings. Electrochemical biosensors, combined with potentiostats, can display the characteristics of a sample's redox reactions in the form of potential or current, and can be commonly applied to DNA identification, protein classification, and glucose measurement.

[0003] The measurement module for electrochemical sensors mainly uses a structure that combines a potentiostat and a three-electrode electrochemical sensor, and the three electrodes are composed of a working electrode (WE), a counter electrode (CE), and a reference electrode (RE). The potentiostat maintains a constant voltage at the reference electrode of the electrochemical sensor and uses a transimpedance amplifier (TIA) that receives the current signal generated between the working electrode and the counter electrode as input and converts it into a voltage.

[0004] The background technology of the invention has been prepared to facilitate a better understanding of the present invention. It should not be construed as an admission that the matters described in the background technology of the invention constitute prior art.

[0005] The conventional potentiostat circuit consists of a constant voltage circuit that maintains the voltage between RE and WE of a three-electrode electrochemical sensor, and a current-voltage conversion circuit that can detect the current generated by the electrochemical reaction between WE and CE.

[0006] The inventors of the present invention recognized that the conventional potentiostat circuit has a complex configuration and has the disadvantage that its characteristics may be degraded due to mismatch caused by process dispersion of passive components including resistors and / or capacitors.

[0007] The inventors of the present invention recognized that the flicker noise characteristics of the sensor readout circuit are important because the current generated from the electrochemical sensor is a very slow signal of less than kHz and has a size of μA, and developed an electrochemical sensor detection device that improves performance degradation due to mismatch in the process by using a dynamic element matching technique in a current mirror, a transimpedance amplifier, and / or a digital-to-analog converter.

[0008] Accordingly, the problem to be solved by the present invention is to provide an electrochemical sensor detection device based on a potentiostat, which has low noise and high precision characteristics.

[0009] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] In order to solve the aforementioned problem, an electrochemical sensor detection device based on a potentiostat according to one embodiment of the present invention is provided. The device comprises a digital-to-analog converter (DAC) configured to receive a digital signal from a waveform generator and digital logic and output an analog signal corresponding to a reference voltage, a control amplifier (CA) configured to receive the analog signal corresponding to the reference voltage and apply the reference voltage to a reference electrode (RE), a gain-boosting current mirror configured to copy a sensor current of an electrochemical sensor and output the sensor copy current, a transimpedance amplifier configured to convert the sensor copy current into a voltage signal, a low-pass filter configured to block a high-frequency band signal component of the voltage signal, and an analog-to-digital converter (ADC) configured to perform digital signal processing on a signal passing through the low-pass filter, wherein at least one of the gain-boosting current mirror or the transimpedance amplifier applies a dynamic element matching technique (DEM) using a plurality of choppers and a plurality of DEM clock signals.

[0011] According to a feature of the present invention, the gain-boosting current mirror includes a gain-boosting amplifier, a plurality of choppers, and a plurality of transistors, and the plurality of choppers can change a connection structure between each terminal of the plurality of transistors and an input terminal or an output terminal of the gain-boosting amplifier using the plurality of DEM clock signals.

[0012] According to another feature of the present invention, the plurality of choppers may include a first chopper, a second chopper, and a third chopper, and the plurality of transistors may include a first transistor, a second transistor, a third transistor, and a fourth transistor, and the first chopper may be positioned between gate terminals of the third transistor and the fourth transistor and an output terminal of the gain-boosting amplifier, the second chopper may be positioned between drain terminals of the first transistor and the second transistor and an input terminal of the gain-boosting amplifier, and the third chopper may be positioned between drain terminals of the first transistor and the second transistor and source terminals of the third transistor and the fourth transistor.

[0013] According to another feature of the present invention, the plurality of DEM clock signals include a first DEM clock signal applied to the first chopper, a second DEM clock signal applied to the second chopper, and a third DEM clock signal applied to the third chopper, and the gain-boosting current mirror can be changed into one of a first state, a second state, a third state, or a fourth state based on the first to third choppers operating using the first to third DEM clock signals, respectively.

[0014] According to another feature of the present invention, the first state of the gain-boosting current mirror is such that the source terminal of the third transistor is connected to the drain terminal of the second transistor, and the gate terminal of the third transistor is connected to the negative output terminal of the gain-boosting amplifier, the second state of the gain-boosting current mirror is such that the drain terminal of the first transistor is connected to the source terminal of the fourth transistor, and the gate terminal of the third transistor is connected to the passive output terminal of the gain-boosting amplifier, the third state of the gain-boosting current mirror is such that the drain terminal of the first transistor is connected to the source terminal of the third transistor, and the gate terminal of the third transistor is connected to the passive output terminal of the gain-boosting amplifier, and the fourth state of the gain-boosting current mirror is such that the drain terminal of the first transistor is connected to the source terminal of the third transistor, and the gate terminal of the third transistor is connected to the passive output terminal of the gain-boosting amplifier. The terminal can be connected to the negative output terminal of the gain-boosting amplifier.

[0015] According to another feature of the present invention, the transimpedance amplifier includes two feedback loops, each having a feedback resistor and a feedback capacitor positioned in parallel, a fourth chopper positioned at one end of the feedback resistor and the feedback capacitor, and a fifth chopper positioned at the other end of the feedback resistor and the feedback capacitor, wherein the fourth chopper and the fifth chopper can change a feedback loop connection structure between an input terminal or an output terminal of the transimpedance amplifier using the plurality of DEM clock signals.

[0016] According to another feature of the present invention, the digital-to-analog converter includes a resistor and switch array, a digital buffer, a thermometer decoder, and a DEM circuit, wherein the DEM circuit may include a pseudo-random number generator and a plurality of multiplexers. In addition, the digital-to-analog converter may be characterized by applying a dynamic element matching technique (DEM) using the thermometer decoder and the DEM circuit.

[0017] According to another feature of the present invention, the thermometer decoder is configured to convert the most significant bit (MSB) into a thermometer code, and the DEM circuit can be configured to change the thermometer code into an output code using selection signals of a plurality of the multiplexers input according to a predetermined switching sequence.

[0018] According to another feature of the present invention, the digital-to-analog converter,

[0019] It may include a first digital-to-analog converter (DAC) configured to provide the analog signal corresponding to the reference voltage to the transimpedance amplifier, and a first digital-to-analog converter (DAC) configured to provide the analog signal corresponding to the reference voltage to the control amplifier.

[0020] In order to solve the aforementioned problem, an electrochemical sensor detection system based on a potentiostat for detecting a multi-channel signal according to one embodiment of the present invention is provided. The system comprises an electrochemical sensor array including a plurality of electrochemical sensors, a shift register selecting one of the plurality of electrochemical sensors using a clock signal, and an electrochemical sensor detection device connected to the electrochemical sensor array by at least one electrode, wherein the electrochemical sensor detection device comprises a digital-to-analog converter (DAC) configured to receive a digital signal from a waveform generator and a digital logic and output an analog signal corresponding to a reference voltage, a gain-boosting current mirror configured to copy a sensor current of each of the plurality of electrochemical sensors and output the sensor copy current, and a transimpedance amplifier configured to convert the sensor copy current into a voltage signal, wherein at least one of the gain-boosting current mirror or the transimpedance amplifier applies a dynamic element matching technique (DEM) using a plurality of choppers and a plurality of DEM clock signals, and the digital-to-analog converter (DAC) applies a dynamic element matching technique (DEM) using a thermometer decoder and a DEM circuit. It is characterized by.

[0021] Specific details of other embodiments are included in the detailed description and drawings.

[0022] According to the present invention, by applying a dynamic matching technique to a gain-boosting current mirror, performance degradation due to mismatch occurring during the manufacturing process of an electrochemical sensor detection circuit can be improved. Furthermore, by applying a chopper stabilization technique to the input and cascode stages of the gain-boosting amplifier included in the gain-boosting current mirror, flicker noise characteristics can be improved, enabling accurate detection of sensor current, which is a low-frequency band signal.

[0023] In addition, the present invention can improve the error of the output signal, which is a performance degradation caused by mismatch occurring during the process of the electrochemical sensor detection circuit, by applying a dynamic matching technique to the input and output terminals of a transimpedance amplifier that converts current into voltage in an electrochemical sensor detection circuit.

[0024] The present invention can improve performance degradation due to mismatch occurring during the process of an electrochemical sensor detection circuit by applying a dynamic matching technique to a digital-to-analog converter included in an electrochemical sensor detection device, and can eliminate resistance value errors due to random errors, gradient errors, etc. occurring due to mismatch of a resistor array.

[0025] The effects according to the present invention are not limited to those exemplified above, and more diverse effects are included within the present invention.

[0026] FIG. 1 is a block diagram showing the configuration of an electrochemical sensor detection system based on a potentiostat according to an embodiment of the present invention.

[0027] FIG. 2 is a circuit diagram showing the configuration of an electrochemical sensor detection system based on a potentiostat that applies a dynamic matching technique according to an embodiment of the present invention.

[0028] FIG. 3 is a timing diagram of a clock signal (f_DEM) applied to apply a dynamic element matching technique to the first to third choppers according to an embodiment of the present invention.

[0029] FIG. 4 is an exemplary diagram of a gain-boosting current mirror using a dynamic element matching technique according to an embodiment of the present invention.

[0030] FIG. 5 is a block diagram of a digital-to-analog converter using a dynamic element matching technique according to an embodiment of the present invention.

[0031] FIG. 6 is a block diagram showing the configuration of a 4-to-15 thermometer decoder and DEM circuit included in a digital-to-analog converter applying a dynamic element matching technique according to an embodiment of the present invention.

[0032] Fig. 7 is a timing diagram of a selection signal and a switching sequence applied to a multiplexer included in the DEM circuit of Fig. 6.

[0033] FIG. 8 is a block diagram showing the configuration of an electrochemical sensor detection system based on a potentiostat according to an embodiment of the present invention and detecting a multi-channel signal.

[0034] FIG. 9 is a graph comparing Monte-Carlo simulation results for the output voltage of a transimpedance amplifier before and after application of a dynamic element matching technique according to an embodiment of the present invention to a gain-boosting current mirror and a transimpedance amplifier.

[0035] FIG. 10 is a graph comparing Monte-Carlo simulation results for offset errors when a dynamic element matching technique according to an embodiment of the present invention is applied to a thermometer decoder of a digital-to-analog converter.

[0036] Figure 11 is a graph showing the results of an experiment using cyclic voltammetry (CV) on an electrochemical sensor detection device that detects a single channel signal according to an embodiment of the present invention.

[0037] Figure 12 is a graph showing part of the experimental results of Figure 11 as a voltage-current curve.

[0038] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. In connection with the description of the drawings, similar reference numerals may be used for similar components.

[0039] In this document, the expressions "has," "may have," "includes," or "may include" indicate the presence of a feature (e.g., a number, function, operation, or component such as a part), but do not exclude the presence of additional features.

[0040] In this document, the expressions "A or B," "at least one of A and / or B," or "one or more of A or / and B" can include all possible combinations of the listed items. For example, "A or B," "at least one of A and B," or "at least one of A or B" can all refer to cases where (1) at least one A is included, (2) at least one B is included, or (3) at least one A and at least one B are included.

[0041] The terms "first," "second," "first," or "second," as used herein, may describe various components, regardless of order and / or importance, and are only used to distinguish one component from another, without limiting the components. For example, a first user device and a second user device may represent different user devices, regardless of order or importance. For example, without departing from the scope of the rights set forth in this document, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0042] When it is said that a component (e.g., a first component) is "(operatively or communicatively) coupled with / to" or "connected to" another component (e.g., a second component), it should be understood that the component is directly coupled to the other component, or can be connected via another component (e.g., a third component). Conversely, when it is said that a component (e.g., a first component) is "directly coupled to" or "directly connected to" another component (e.g., a second component), it should be understood that no other component (e.g., a third component) exists between the first component and the other component.

[0043] The expression "configured to" as used herein can be used interchangeably with, for example, "suitable for," "having the capacity to," "designed to," "adapted to," "made to," or "capable of." The term "configured to" does not necessarily mean something is "specifically designed to" in hardware. Instead, in some contexts, the expression "a device configured to" can mean that the device, together with other devices or components, is "capable of." For example, the phrase "a processor configured (or set) to perform A, B, and C" may mean a dedicated processor (e.g., an embedded processor) for performing those operations, or a general-purpose processor (e.g., a CPU or application processor) that can perform those operations by executing one or more software programs stored in a memory device.

[0044] The terms used in this document are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this document. Terms defined in general dictionaries among the terms used in this document may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this document. In some cases, even if a term is defined in this document, it cannot be interpreted to exclude the embodiments of this document.

[0045] The individual features of the various embodiments of the present invention can be partially or wholly combined or combined with each other, and as can be fully understood by those skilled in the art, various technical connections and operations are possible, and each embodiment can be implemented independently of each other or can be implemented together in a related relationship.

[0046] For clarity in the interpretation of this specification, the terms used in this specification are defined below.

[0047] 'Potentiostat' means a potentiostat, a potentiostat, a potentiostat, or an electrochemical instrument. A potentiostat can be used to investigate reaction mechanisms related to redox chemistry and other chemical phenomena. A potentiostat can control and / or measure potential or current. A potentiostat can be composed of an electrical circuit that senses the resistance of a cell containing electrode(s) to control the potential across the cell (e.g., the voltage difference between a reference electrode and a working electrode) and to vary the current supplied to the system (e.g., the current between the working electrode and a counter electrode).

[0048] The "three electrodes" of an electrochemical sensor or potentiostat consist of a reference electrode (RE), a working electrode (WE), and a counter electrode (CE). The electrodes of an electrochemical sensor can be mounted in various electrochemical cells depending on the experimental purpose.

[0049] A "reference electrode" can be defined as an electrode that serves as a reference point for measuring or controlling the potential of the working electrode. The potential relative to the reference electrode appears at the working electrode. Because the amount of current flowing through the reference electrode is negligibly small, the electrochemical potential of the reference electrode can be considered nearly constant.

[0050] The "working electrode" can be defined as the electrode where the potential is controlled and the current measured, and where the reaction that is the objective of the experiment occurs. The "counter electrode" refers to the electrode that electrically completes the circuit, allowing charge to flow in the electrochemical cell.

[0051] "Chopper" is a term for a circuit that performs a switching operation. It refers to a power control circuit that can supply arbitrary voltage and current by turning the power on and off at regular intervals. Chopping is the process of modulating the frequency to higher levels to separate low-frequency noise from the signal, and the chopper conserves energy at the chopped frequency, thereby maintaining low noise levels at low frequencies. A chopper can also be referred to as a switching converter.

[0052] The "Dynamic Element Matching (DEM) technique" is a technique used to compensate for mismatches between signal paths. It refers to a method of dynamically selecting different elements so that different signal paths have the same average circuit characteristics. The dynamic matching technique according to an embodiment of the present disclosure operates by compensating for process mismatches by having switches within the chopper alternately connect left and right.

[0053] FIG. 1 is a block diagram showing the configuration of an electrochemical sensor detection system based on a potentiostat according to an embodiment of the present invention.

[0054] Referring to FIG. 1, the electrochemical sensor detection system may include an electrochemical sensor (100) and an electrochemical sensor detection device (1000).

[0055] An electrochemical sensor (100) according to an embodiment of the present invention may be a three-electrode electrochemical sensor including a working electrode (WE), a counter electrode (CE), and a reference electrode (RE).

[0056] An electrochemical sensor detection device (1000) according to an embodiment of the present invention may include an electrochemical sensor detection circuit based on a potentiostat. The electrochemical sensor detection device (1000) may be an electrochemical sensor detection device that detects a single-channel signal of the electrochemical sensor (100). As another example, the electrochemical sensor detection device (1000) may be an electrochemical sensor detection device that detects a multi-channel signal of the electrochemical sensor (100).

[0057] The electrochemical sensor detection device (1000) can maintain the voltage of the reference electrode (RE) constant and receive a current signal generated between the working electrode (WE) and the counter electrode (CE) as input and convert it into voltage.

[0058] The electrochemical sensor detection device (1000) may include a gain-boosting current mirror (IAMP) (200) that copies the sensor current, a transimpedance amplifier (TIA) (300) that converts the current into voltage, a low pass filter (LPF) (400) that passes a low frequency band signal, and / or an analog-to-digital converter (ADC) (500) that converts an analog signal into a digital signal. In addition, the electrochemical sensor detection device (1000) may include a control amplifier (CA) (600) that applies a reference voltage (e.g., SCAN voltage) to a reference electrode (RE) of the electrochemical sensor, first and second digital-to-analog converters (DACs) (700, 800) that convert a digital signal into an analog signal, and / or a signal processor (900) that adjusts an output voltage of the digital-to-analog converter and generates a clock signal. The signal processor (900) may include digital logic.

[0059] The electrochemical sensor detection device (1000) can generate a specific signal suitable for the experimental purpose that the user wants to conduct using a signal processor (900), and transmit the specific signal to a second digital-to-analog converter (800). The specific signal can be sent to a control amplifier (600) via the second digital-to-analog converter (800), and the control amplifier (600) can adjust a reference voltage so that it can be applied in an electrochemical cell, and can, for example, make it into a SCAN voltage and apply it to a reference electrode (RE).

[0060] FIG. 2 is a circuit diagram showing the configuration of an electrochemical sensor detection system based on a potentiostat that applies a dynamic matching technique according to an embodiment of the present invention.

[0061] An electrochemical sensor detection system based on a potentiostat applying a dynamic matching technique according to an embodiment of the present invention may include an electrochemical sensor (100) and an electrochemical sensor detection device (1000) using a dynamic element matching (DEM) technique. More specifically, the dynamic element matching (DEM) technique may be applied to a gain-boosting current mirror (200), a transimpedance amplifier (300), and / or first and second digital-to-analog converters (DACs) (700, 800).

[0062] Referring to Fig. 2, VDD is a supply voltage and GND means ground. I_SEN is a sensor current generated by the oxidation-reduction reaction of the electrochemical sensor (100), V_SCAN is a SCAN voltage which is a digital signal controlling a digital-to-analog converter, f_DEM1, f_DEM2, and f_DEM3 are clock signals for applying a dynamic element matching (DEM) technique, and f_ADC is a clock signal including a sampling clock and a master clock for operating an analog-to-digital converter.

[0063] The operation sequence of an electrochemical sensor detection system based on a potentiostat applying a dynamic matching technique according to an embodiment of the present invention is described.

[0064] The signal processor (900) can generate a SCAN voltage (V_SCAN) corresponding to a specific signal suitable for the experimental purpose that the user wishes to conduct, and transmit the SCAN voltage (V_SCAN) to the second digital-to-analog converter (800). The SCAN voltage (V_SCAN) in the form of a digital signal can be converted into an analog signal through the second digital-to-analog converter (800).

[0065] The first digital-to-analog converter (700) can receive a digital code from the signal processor (900) and generate and output an analog voltage signal corresponding to the SCAN voltage (V_SCAN) of the transimpedance amplifier (300). The second digital-to-analog converter (800) can receive a digital code from the signal processor (900) and supply an analog signal corresponding to the SCAN voltage (V_SCAN) to the control amplifier (600). Details regarding the specific operation methods of the first digital-to-analog converter (700) and the second digital-to-analog converter (800) will be described later with reference to FIGS. 4 and 5.

[0066] When an analog signal corresponding to the SCAN voltage (V_SCAN) is supplied from the first digital-to-analog converter (700) to the inverting input terminal ((-) terminal) of the control amplifier (600), the control amplifier (600) forms a negative feedback loop and can apply an analog signal corresponding to the SCAN voltage (V_SCAN) as a reference voltage between the reference electrode (RE) and the counter electrode (CE) of the electrochemical sensor (100).

[0067] Due to the virtual ground of the input terminal of the control amplifier (600) or the transimpedance amplifier (300), an analog signal corresponding to the SCAN voltage (V_SCAN) output from the first or second digital-to-analog converters (700, 800) can be applied to the reference electrode (RE) of the electrochemical sensor as a common mode voltage.

[0068] When a SCAN voltage (V_SCAN) is applied between the reference electrode (RE) and the counter electrode (CE) of the electrochemical sensor (100), a current can be generated between the working electrode (WE) and the counter electrode (CE) of the electrochemical sensor (100) due to the impedance inside the electrochemical sensor (100). The current generated between the working electrode (WE) and the counter electrode (CE) of the electrochemical sensor (100) corresponds to the sensor current (I_SEN) generated by the oxidation-reduction reaction of the electrochemical sensor (100).

[0069] The sensor current (I_SEN) generated from the electrochemical sensor (100) can be copied to the input terminal of a transimpedance amplifier (TIA) (300) through a gain-boosting current mirror (200) to be converted and amplified into a voltage signal.

[0070] A gain-boosting current mirror (200) can increase the output impedance compared to a conventional current mirror structure by using a gain-boosting amplifier (20). The gain-boosting current mirror (200) can include four NMOS transistors. The gain-boosting current mirror (200) can be a cascode current mirror in which a fourth NMOS transistor (MN_4) is connected in series to a second NMOS transistor (MN_2).

[0071] The four NMOS transistors may be referred to as a first NMOS transistor (MN_1), a second NMOS transistor (MN_2), a third NMOS transistor (MN_3), and a fourth NMOS transistor (MN_4), respectively. In addition, the current (I_(SEN_IN)) input to the gain-boosting current mirror (200) can generate a gate voltage of the first NMOS transistor (MN_1) by using a diode connected structure that directly connects the drain terminal of the third NMOS transistor (MN_3) to the gate terminal of the first NMOS transistor (MN_1).

[0072] The transconductance of the second NMOS transistor (MN_2) can convert the gate voltage of the first NMOS transistor (MN_1) into a sensor copy current (I_(SEN_OUT)) copied from the gain-boosting current mirror (200).

[0073] Here, the current ratio of the current (I_(SEN_IN)) input to the gain-boosting current mirror (200) and the current (I_(SEN_OUT)) output from the gain-boosting current mirror (200) can be determined by the ratio (W / L) of the width (Width) and the length (Length) of the channel regions of each of the third NMOS transistor (MN_3) and the fourth NMOS transistor (MN_4). The gain-boosting current mirror (200) may have poor accuracy due to mismatch caused by process dispersion of the third NMOS transistor (MN_3) and the fourth NMOS transistor (MN_4) driving the current mirror and the influence of low-frequency noise of the gain-boosting amplifier (20).

[0074] According to an embodiment of the present disclosure, the gain-boosting current mirror (200) may include three choppers. Specifically, the gain-boosting current mirror (200) may include a first chopper (21) positioned between the gate terminals of the third NMOS transistor (MN_3) and the fourth NMOS transistor (MN_4) and the output terminal of the gain-boosting amplifier (20), a second chopper (22) positioned between the drain terminals of the first NMOS transistor (MN_1) and the second NMOS transistor (MN_2) and the input terminal of the gain-boosting amplifier (20), and / or a third chopper (23) positioned between the four NMOS transistors (MN_1, MN_2, MN_3, MN_4). Specifically, the third chopper (23) can be located between the drain terminals of the first NMOS transistor (MN_1) and the second NMOS transistor (MN_2) and the source terminals of the third NMOS transistor (MN_3) and the fourth NMOS transistor (MN_4).

[0075] According to an embodiment of the present disclosure, by applying a dynamic matching technique and a chopper stabilization technique to three choppers of a gain-boosting current mirror (200), mismatch and flicker noise due to process dispersion of transistors can be simultaneously reduced. Accordingly, the reliability of the gain-boosting current mirror (200) can be secured. Here, flicker noise refers to noise that mainly occurs in a low-frequency range and can be generated by various factors such as the movement of atoms and changes in electric circuits. Details on a specific operating method of the gain-boosting current mirror (200) will be described later with reference to FIG. 3.

[0076] The sensor radiation current (I_(SEN_OUT)) radiated from the gain-boosting current mirror (200) can be converted into a voltage signal by the feedback impedance of the transimpedance amplifier (300). Assuming that the open-loop gain of the transimpedance amplifier (300) is ideally infinite, the output signal of the transimpedance amplifier (300) can be determined by the resistance value of the feedback loop. However, since the poly-silicon resistor used in the CMOS (Complementary Metal-Oxide-Semiconductor) integrated circuit is vulnerable to process mismatch, an error may occur in the resistance value, and accordingly, an error may occur in the differential output signal of the transimpedance amplifier (300).

[0077] The feedback loop (30) of the transimpedance amplifier (300) may be composed of two negative feedback loops. A feedback resistor (R__F) and a feedback capacitor (C_F) may be positioned in parallel in the two negative feedback loops, respectively. A fourth chopper (31) and a fifth chopper (32) may be positioned at both ends of the feedback resistor (R__F) and the feedback capacitor (C_F) positioned in parallel in the transimpedance amplifier (300). Specifically, a fourth chopper (31) may be positioned at one end of the feedback resistor (R__F) and the feedback capacitor (C_F) in the first negative feedback loop and at one end of the feedback resistor (R__F) and the feedback capacitor (C_F) in the second negative feedback loop, and a fifth chopper (32) may be positioned at the other end of the feedback resistor (R__F) and the feedback capacitor (C_F) in the first negative feedback loop and at the other end of the feedback resistor (R__F) and the feedback capacitor (C_F) in the second negative feedback loop.

[0078] Therefore, according to the embodiment of the present disclosure, by positioning the fourth chopper (31) and the fifth chopper (32) in the feedback loop (30) of the transimpedance amplifier (300), the input currents are crossed by applying a dynamic element matching technique to the input terminal and the output terminal of the transimpedance amplifier (300), that is, by changing the feedback loop connection structure between the input terminal and the output terminal of the transimpedance amplifier (300), the error of the output signal can be improved.

[0079] The output signal of the transimpedance amplifier (300) can be input to a low-pass filter (LPF) (400). The low-pass filter (LPF) (400) can block and output signals in the high-frequency band from the output signal of the transimpedance amplifier (300).

[0080] The output signal of the low-pass filter (LPF) (400) can be input to an analog-to-digital converter (ADC) (500). The analog-to-digital converter (ADC) (500) can convert the output signal of the low-pass filter (LPF) (400) into a digital signal and output it to a signal processor (900).

[0081] FIG. 3 is a timing diagram of a clock signal (f_DEM) applied to apply a dynamic element matching technique to the first to third choppers according to an embodiment of the present invention, and FIG. 4 is an exemplary diagram of a gain-boosting current mirror applying a dynamic element matching technique according to an embodiment of the present invention. Hereinafter, this will be described with reference to FIG. 2.

[0082] Referring to FIGS. 2 and 3, examples of clock signals (f_DEM1, f_DEM2, f_DEM3, FIG. 2) applied to a first chopper (21, FIG. 2), a second chopper (22, FIG. 2), and a third chopper (23, FIG. 2), respectively, are illustrated in a timing diagram (24). The first DEM clock signal (f_DEM1) may be applied to the first chopper (21, FIG. 2) to implement a dynamic element matching technique of the gain-boosting current mirror (200, FIG. 2). The second DEM clock signal (f_DEM2) may be applied to the second chopper (22, FIG. 2) to implement a dynamic element matching technique of the gain-boosting current mirror (200, FIG. 2). The third DEM clock signal (f_DEM3) can be applied to the third chopper (23, FIG. 2) to implement the dynamic element matching technique of the gain-boosting current mirror (200, FIG. 2). In addition to the above-described clock signals (f_DEM1, f_DEM2, f_DEM3), various clock signals can be applied to the first chopper (21, FIG. 2), the second chopper (22, FIG. 2), and the third chopper (23, FIG. 2), and the order or timing of the clock signals does not limit the scope of the present invention. By applying clock signals according to the embodiments of the invention to the first chopper (21, FIG. 2), the second chopper (22, FIG. 2), and the third chopper (23, FIG. 2), the asymmetry of the gain-boosting current mirror (200, FIG. 2) can be utilized to reduce mismatch due to process dispersion of the transistor.

[0083] Referring to FIG. 4, the average value of errors due to process mismatch of the transistors can be eliminated by changing the connection structure between the four NMOS transistors included in the gain-boosting current mirror (200, FIG. 2) and the gain-boosting amplifier (20, FIG. 2) (or the operation of the first chopper (21, FIG. 2) to the third chopper (23, FIG. 2)) according to four states.

[0084] According to the circuit structure of the gain-boosting current mirror (201) in the first state (S1), the source terminal of the third NMOS transistor (MN_3) can be connected to the drain terminal of the second NMOS transistor (MN_2), the source terminal of the fourth NMOS transistor (MN_4) can be connected to the drain terminal of the first NMOS transistor (MN_1), the gate terminal of the third NMOS transistor (MN_3) can be connected to the negative (-) output terminal of the gain-boosting amplifier (20_1), and the gate terminal of the fourth NMOS transistor (MN_4) can be connected to the passive (+) output terminal of the gain-boosting amplifier (20_1).

[0085] According to the circuit structure of the gain-boosting current mirror (202) of the second state (S2), the source terminal of the third NMOS transistor (MN_3) can be connected to the drain terminal of the second NMOS transistor (MN_2), the drain terminal of the first NMOS transistor (MN_1) can be connected to the source terminal of the fourth NMOS transistor (MN_4), the gate terminal of the third NMOS transistor (MN_3) can be connected to the passive (+) output terminal of the gain-boosting amplifier (20_2), and the gate terminal of the fourth NMOS transistor (MN_4) can be connected to the negative (-) output terminal of the gain-boosting amplifier (20_1).

[0086] According to the circuit structure of the gain-boosting current mirror (203) of the third state (S3), the source terminal of the third NMOS transistor (MN_3) can be connected to the drain terminal of the first NMOS transistor (MN_1), the source terminal of the fourth NMOS transistor (MN_4) can be connected to the drain terminal of the second NMOS transistor (MN_2), the gate terminal of the third NMOS transistor (MN_3) can be connected to the passive (+) output terminal of the gain-boosting amplifier (20_3), and the gate terminal of the fourth NMOS transistor (MN_4) can be connected to the negative (-) output terminal of the gain-boosting amplifier (20_1).

[0087] According to the circuit structure of the gain-boosting current mirror (204) of the fourth state (S4), the source terminal of the third NMOS transistor (MN_3) can be connected to the drain terminal of the first NMOS transistor (MN_1), the source terminal of the fourth NMOS transistor (MN_4) can be connected to the drain terminal of the second NMOS transistor (MN_2), the gate terminal of the third NMOS transistor (MN_3) can be connected to the negative (-) output terminal of the gain-boosting amplifier (20_4), and the gate terminal of the fourth NMOS transistor (MN_4) can be connected to the passive (+) output terminal of the gain-boosting amplifier (20_1).

[0088] A gain-boosting current mirror applying a dynamic element matching technique according to an embodiment of the present invention can be implemented as a current mirror with increased precision by combining three choppers and four stages applying a dynamic matching technique to eliminate errors due to flicker noise and transistor mismatch as an average value.

[0089] Fig. 5 is a block diagram of a digital-to-analog converter using a dynamic element matching technique according to an embodiment of the present invention. Fig. 6 is a block diagram showing the configuration of a 4-to-15 thermometer decoder and a DEM circuit included in a digital-to-analog converter using a dynamic element matching technique according to an embodiment of the present invention. Fig. 7 is a timing diagram of a selection signal and a switching sequence applied to a multiplexer included in the DEM circuit of Fig. 6.

[0090] The digital-to-analog converter (DAC) (50) according to the embodiment of FIG. 5 can be applied to the first digital-to-analog converter (DAC) (700) to the second digital-to-analog converter (800) illustrated in FIGS. 1 and 2.

[0091] In one embodiment, the digital-to-analog converter (DAC) (50) may be an R-2R digital-to-analog converter with a 12-bit resolution and high accuracy, capable of sampling at a frequency band of up to Mega Hertz (MHz).

[0092] A digital-to-analog converter (DAC) (50) may include a 4-bit Most-Significant Bit (MSB) (51) and an 8-bit Least-Significant Bit (LSB) (52), a 4-to-15 thermometer decoder (53), a DEM circuit (Dynamic Element Matching Circuit) (54), an 8-bit digital buffer (55), and / or a resistor and switch array (56). A digital input code in the form of a digital signal may be input to the digital-to-analog converter (DAC) (50), and an analog output signal in the form of an analog signal may be output.

[0093] The R-2R digital-to-analog converter has a disadvantage in that the matching between the resistor with the R value and the resistor with the 2R value is weak due to process errors. Therefore, the 4-bit MSB (51) can utilize a DAC structure using a thermometer code method, and the 8-bit LSB (52) can utilize an R-2R DAC structure.

[0094] A digital-to-analog converter (DAC) (50) may experience performance degradation due to random errors and / or gradient errors. Random errors may be caused by various factors such as PVT variation and / or noise within the system. Gradient errors may cause linearity to decrease due to consistent deviations in resistance values, which may in turn affect integral non-linearity (INL) and differential non-linearity (DNL) errors. Therefore, according to an embodiment of the present invention, a dynamic element matching (DEM) technique may be applied to a thermometer code type DAC structure (or a 4-to-15 thermometer decoder (53)) included in a digital-to-analog converter (DAC) (50).

[0095] According to an embodiment of the present invention, the DEM circuit (54) may be composed of a pseudo-random number generator having a constant period and a two-stage multiplexer.

[0096] A 4-bit digital signal corresponding to MSB can be input to a 4-to-15 thermometer decoder (53), and the 4-bit digital signal corresponding to MSB can be converted into a 15-bit thermometer code. The 15-bit thermometer code can be randomly changed according to a switching sequence (“00” - “01” - “10” - “11”). The DEM circuit (54) can operate based on a combination of four switching modes (“00”, “01”, “10”, “11”) randomly generated according to a pseudo-random number generator signal. The pseudo-random number generator generates a 1-bit selection signal (SEL1, SEL0) and can randomly mix the 15-bit thermometer code according to the switching mode.

[0097] Referring to FIG. 6, the DEM circuit (64) may include a plurality of multiplexers (MUXs) including a first MUX (1) and a second MUX (2) and a plurality of switches (3). According to one embodiment, the DEM circuit (64) may include 30 MUXs and 15 switches.

[0098] Referring to FIGS. 6 and 7, a 1-bit selection signal (SEL1, SEL0) is an example of a control signal applied to a multiplexer (MUX) included in a DEM circuit (64), and a switching sequence (SEL<1:0>) means the order of a combination of selection signals (e.g., 01) of at least one multiplexer (MUX) (e.g., two MUX) that can 1:1 change, match, or map a 15-bit thermometer code (T<15:1>) to an output code (D<15:1>). For example, according to an embodiment of the present invention, T <15> Wow T <1> By this first MUX(1) and SEL0 selection signal, T <1> This is selected and D by the second MUX(2) and SEL1 selection signal <9> This can be selected and output (T1⇒D9). Therefore, when one of the 15-bit thermometer codes is changed to one of the output codes, the selection signal combination can be set as SEL0 and SEL1 as the selection signals of the first MUX (1) and the second MUX (2), respectively, and can be expressed as “01”. The selection signal combination can be optimized and applied according to the determined switching operation and switching order.

[0099] For example, the switching sequence can be set in the order of “00” - “01” - “10” - “11” according to a given clock signal, as illustrated in FIG. 7.

[0100] Referring to FIGS. 5 to 7, when the selection signal combination during the switching sequence is “00” as an example, for the 4-to-15 thermometer code (T<15:1>) output by the thermometer decoder (53, 63) and input to the DEM circuit (54, 64), the output code (D<15:1>) selected by the DEM circuit (54, 64) is as follows. Hereinafter, the thermometer codes may be expressed as T1 to T15, and the output codes of the DEM circuit (54) may be expressed as D1 to D15.

[0101] T1 ⇒ D9

[0102] T2 ⇒ D6

[0103] T3 ⇒ D11

[0104] T4 ⇒ D4

[0105] T5 ⇒ D13

[0106] T6 ⇒ D2

[0107] T7 ⇒ D15

[0108] T8 ⇒ D1

[0109] T9 ⇒ D14

[0110] T10 ⇒ D3

[0111] T11 ⇒ D12

[0112] T12 ⇒ D5

[0113] T13 ⇒ D10

[0114] T14 ⇒ D7

[0115] T15 ⇒ D8

[0116] A digital-to-analog converter applying a dynamic element matching technique according to an embodiment of the present invention can reduce the complexity of design, reduce the area and power consumption of a circuit, and eliminate errors in resistance values ​​due to random errors and / or gradient errors randomly occurring due to an external environment by averaging them through a switching sequence.

[0117] FIG. 8 is a block diagram showing the configuration of an electrochemical sensor detection system based on a potentiostat according to an embodiment of the present invention and detecting a multi-channel signal.

[0118] Referring to FIG. 8, the electrochemical sensor detection system may include an electrochemical sensor array (100_1, 100_2, 100_3) for detecting multi-channel signals, an electrochemical sensor detection device (1000), and a shift register (1100). The electrochemical sensor detection device (Readout IC, 1000) of FIG. 8 may be applied to the electrochemical sensor detection device (1000) of FIGS. 1 and 2.

[0119] According to an embodiment of the present invention, the electrochemical sensor array (100_1, 100_2, 100_3) may include three electrochemical sensors that detect a triple-channel signal.

[0120] The first electrochemical sensor (100_1), the second electrochemical sensor (100_2), or the third electrochemical sensor (100_3) may each be configured with three electrodes including a reference electrode (RE), a working electrode (WE), and a counter electrode (CE). I_SEN1 is a sensor current generated by the oxidation-reduction reaction of the first electrochemical sensor (100_1), I_SEN2 is a sensor current generated by the oxidation-reduction reaction of the second electrochemical sensor (100_2), and I_SEN3 is a sensor current generated by the oxidation-reduction reaction of the third electrochemical sensor (100_3).

[0121] The shift register (1100) can select the first electrochemical sensor (100_1), the second electrochemical sensor (100_2), or the third electrochemical sensor (100_3) according to the clock signal (CLK).

[0122] An electrochemical sensor detection system that detects a multi-channel signal using an electrochemical sensor array (100_1, 100_2, 100_3) according to an embodiment of the present invention can process a lot of data in the same amount of time compared to an electrochemical sensor detection system that detects a single-channel signal by monitoring multiple samples at once, such as in clinical diagnostics. In addition, the electrochemical sensor detection system that detects a multi-channel signal can adjust and apply the characteristics of the first electrochemical sensor (100_1), the second electrochemical sensor (100_2), and / or the third electrochemical sensor (100_3) so as to have sensitivity and / or specificity for a specific analysis target by using the electrochemical sensor array (100_1, 100_2, 100_3).

[0123] FIG. 9 is a graph comparing Monte-Carlo simulation results for the output voltage of a transimpedance amplifier before and after application of a dynamic element matching technique according to an embodiment of the present invention to a gain-boosting current mirror and a transimpedance amplifier.

[0124] Referring to FIG. 9, in the embodiment of the present invention, when the dynamic element matching technique is not applied to the feedback resistor and feedback capacitor located in the feedback loop between the gain-boosting current mirror and the transimpedance amplifier, the Monte-Carlo simulation results for 1000 samples of the output voltage (TIA output voltage) of the transimpedance amplifier are indicated as 'DEM Disable'.

[0125] On the other hand, referring to FIG. 9, when the dynamic element matching technique is applied by placing choppers on the feedback resistor and feedback capacitor located in the feedback loop between the gain-boosting current mirror and the transimpedance amplifier described above in the embodiment of the present invention, the Monte-Carlo simulation result (101) for 1000 samples of the output voltage of the transimpedance amplifier (TIA output voltage) is indicated as 'DEM Enable'.

[0126] The graph on the right side of Figure 9 is an enlarged version of the graph marked "DEM Enable" on the left side of Figure 9. It can be seen that all 1,000 samples are distributed between 799.8 and 799.975 mV.

[0127] According to an electrochemical sensor detection device according to an embodiment of the present invention, a current of 1 μA is copied to a current mirror through an electrochemical sensor, and the input current can be converted into a voltage corresponding to a value multiplied by a feedback resistance of a transimpedance amplifier.

[0128] When the dynamic element matching technique was not applied, the Monte-Carlo simulation results showed that the standard deviation of 1,000 samples of the output voltage of the transimpedance amplifier was 2.3 mV. On the other hand, when the dynamic element matching technique was applied, the Monte-Carlo simulation results showed that the standard deviation of 1,000 samples of the output voltage of the transimpedance amplifier was 20 μV. Therefore, it can be confirmed that when the dynamic element matching technique according to the embodiment of the present invention is applied to the gain-boosting current mirror and the transimpedance amplifier, the standard deviation of the output voltage of the transimpedance amplifier is significantly reduced, and the performance in terms of the precision of the electrochemical sensor detection device is improved.

[0129] FIG. 10 is a graph comparing Monte-Carlo simulation results for offset errors when a dynamic element matching technique according to an embodiment of the present invention is applied to a thermometer decoder of a digital-to-analog converter. This is described below with reference to FIG. 5.

[0130] The Monte-Carlo simulation results of Fig. 10 are the results of comparing 200 samples of offset errors depending on whether or not a dynamic element matching technique was applied to the thermometer decoder of the digital-to-analog converter (DAC) (50) according to the embodiment of Fig. 5 when 2048 digital input codes were input. In this embodiment, the offset error refers to the offset error of the LSB.

[0131] According to the Monte-Carlo simulation result graph (110) in the case where the dynamic element matching technique is not applied to the thermometer decoder of the digital-to-analog converter, the average value of the offset error was calculated to be -1.4 LSB.

[0132] According to the Monte-Carlo simulation result graph (111) when the dynamic element matching technique is applied to the thermometer decoder of the digital-to-analog converter, the average value of the offset error was calculated to be -0.5 LSB. Therefore, when the dynamic element matching technique according to the embodiment of the present invention is applied to the thermometer decoder of the digital-to-analog converter, the offset error is reduced by an average of 0.9 LSB, and it can be confirmed that the performance is improved in terms of the precision of the electrochemical sensor detection device.

[0133] Figure 11 is a graph showing the results of an experiment using cyclic voltammetry (CV) on an electrochemical sensor detection device that detects a single channel signal according to an embodiment of the present invention.

[0134] Cyclic voltammetry (CV) is an electrochemical technique used to determine the redox reactions of electrically active chemical species and to characterize these reactions through measurements of voltage and / or current. CV can be performed by applying a triangular voltage to a working electrode (WE) and measuring the resulting current change.

[0135] Referring to Fig. 11, the x-axis of the graph may represent time, and the y-axis may represent voltage (V). CH1 represents an output signal (Potentiostat Output) of an electrochemical sensor detection device that detects a single channel signal according to an embodiment of the present invention. CH2 represents a voltage signal of a digital-to-analog converter applied to a counter electrode (CE), and CH3 represents a voltage signal of a digital-to-analog converter applied to a working electrode (WE). CH1 to CH3 may be set to output periodic linear graphs to implement the CV technique.

[0136] When the voltage signal of the digital-to-analog converter applied to the counter electrode (CE) of CH2 increases linearly, the smaller the potential difference between the counter electrode (CE) and the working electrode (WE), the more the current may change due to the oxidation reaction inside the electrochemical sensor.

[0137] Conversely, when the voltage signal of the digital-to-analog converter applied to the counter electrode (CE) of CH2 decreases linearly, the smaller the potential difference between the counter electrode (CE) and the working electrode (WE), the more the current may change due to the reduction reaction inside the electrochemical sensor.

[0138] Figure 12 is a graph showing part of the experimental results of Figure 11 as a voltage-current curve.

[0139] A voltammogram is a graph that shows current versus voltage.

[0140] In the graph of Figure 12, the x-axis represents the voltage (V) corresponding to the potential difference between the working electrode (WE) and the reference electrode (RE). WE-RE )), the y-axis can be current (Input sensor current (μA)).

[0141] The voltage-current curve graph of Fig. 12 shows the results of converting the output voltage of the electrochemical sensor detection device into the sensor current of the electrochemical sensor, based on the case where the potential difference between the counter electrode (CE) of CH2 and the working electrode (WE) of CH3 is ±0.6 V or less when conducting an experiment using the cyclic voltammetry (CV) method of Fig. 11 for each molar concentration of the analysis target (e.g., 1 mM, 2 mM, 5 mM, 10 mM). Therefore, it can be confirmed that the electrochemical sensor detection device according to the embodiment of the present invention is a device capable of precise electrochemical sensing.

[0142] Although the embodiments of the present invention have been described in more detail with reference to the attached drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be implemented without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain it, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all aspects and not restrictive. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

[0143]

[0144] [National Research and Development Project Supporting This Invention]

[0145] [Project ID] 1711197698

[0146] [Project Number] PCP24007M

[0147] [Ministry Name] Ministry of Science and ICT

[0148] [Name of Project Management (Specialist) Institution] Nano Comprehensive Technology Institute

[0149] [Research Project Name] Semiconductor Process-Based Nanomedical Device Development Project

[0150] [Research Project Title] Development of an i-Lab-on-Human-based In-Vital Signal Monitoring System

[0151] [Name of Project Performing Organization] Nano Comprehensive Technology Institute

[0152] Research Period: January 1, 2024 - December 31, 2024

[0153] [National Research and Development Project Supporting This Invention]

[0154] [Project ID] 1415184122

[0155] [Assignment Number] PIC24001M

[0156] Ministry of Trade, Industry and Energy

[0157] [Name of Project Management (Specialist) Institution] Korea Institute of Industrial Technology Planning and Evaluation

[0158] [Research Project Name] Korea-led K-Sensor Technology Development (R&D) for Market Leadership

[0159] [Research Project Name] Development of High-Sensitivity Nano-Optical Biosensor Technology for Rapid On-Site Virus Diagnosis

[0160] [Name of the project performing organization] Electronics and Telecommunications Research Institute

[0161] Research Period: January 1, 2024 - December 31, 2024

[0162] [National Research and Development Project Supporting This Invention]

[0163] [Project ID] 1415184132

[0164] [Assignment Number] PIC24002M

[0165] Ministry of Trade, Industry and Energy

[0166] [Name of Project Management (Specialist) Institution] Korea Institute of Industrial Technology Planning and Evaluation

[0167] [Research Project Name] Korea-led K-Sensor Technology Development (R&D) for Market Leadership

[0168] [Research Project Name] Nano-optical-based Rapid and High-Sensitivity Biosensor Process Platform

[0169] [Name of the project performing organization] Electronics and Telecommunications Research Institute

[0170] Research Period: January 1, 2024 - December 31, 2024

[0171] [National Research and Development Project Supporting This Invention]

[0172] [Project ID] 1711197700

[0173] [Project Number] PCP24005M

[0174] [Ministry Name] Ministry of Science and ICT

[0175] [Name of Project Management (Specialist) Institution] Nano Comprehensive Technology Institute

[0176] [Research Project Name] Semiconductor Process-Based Nanomedical Device Development Project

[0177] [Research Project Name] Nano Medical Sensors (NMS) Platform (Phase 2, Phase 2)

[0178] [Name of Project Performing Organization] Nano Comprehensive Technology Institute

[0179] Research Period: January 1, 2024 - December 31, 2024

Claims

1. A digital-to-analog converter (DAC) configured to receive a digital signal from a waveform generator and digital logic and output an analog signal corresponding to a reference voltage; A control amplifier (CA) configured to receive the analog signal corresponding to the reference voltage and apply the reference voltage to a reference electrode (RE); A gain-boosting current mirror configured to copy a sensor current of an electrochemical sensor and output the sensor copy current; A transimpedance amplifier configured to convert the above sensor radiation current into a voltage signal; A low-pass filter configured to block high-frequency band signal components of the voltage signal; and An analog-to-digital converter (ADC) configured to perform digital signal processing on a signal passing through the low-pass filter; At least one of the above gain-boosting current mirror or the above transimpedance amplifier applies a dynamic element matching technique (DEM) using a plurality of choppers and a plurality of DEM clock signals. Electrochemical sensor detection device based on potentiostat.

2. In paragraph 1, The above gain-boosting current mirror includes a gain-boosting amplifier, the plurality of choppers, and a plurality of transistors, The above plurality of choppers change the connection structure between each terminal of the plurality of transistors and the input terminal or output terminal of the gain-boosting amplifier using the plurality of DEM clock signals. Electrochemical sensor detection device based on potentiostat.

3. In paragraph 2, The above plurality of choppers include a first chopper, a second chopper, and a third chopper, The above plurality of transistors include a first transistor, a second transistor, a third transistor, and a fourth transistor, The first chopper is located between the gate terminals of the third transistor and the fourth transistor and the output terminal of the gain-boosting amplifier, The second chopper is located between the drain terminals of the first transistor and the second transistor and the input terminal of the gain-boosting amplifier, The third chopper is located between the drain terminals of the first transistor and the second transistor and the source terminals of the third transistor and the fourth transistor. Electrochemical sensor detection device based on potentiostat.

4. In paragraph 3, The plurality of DEM clock signals include a first DEM clock signal applied to the first chopper, a second DEM clock signal applied to the second chopper, and a third DEM clock signal applied to the third chopper, The gain-boosting current mirror is changed into one of a first state, a second state, a third state, or a fourth state based on the first to third choppers operating using a first to third DEM clock signal, respectively. Electrochemical sensor detection device based on potentiostat.

5. In paragraph 4, The first state of the gain-boosting current mirror is such that the source terminal of the third transistor is connected to the drain terminal of the second transistor, and the gate terminal of the third transistor is connected to the negative output terminal of the gain-boosting amplifier. The second state of the gain-boosting current mirror is such that the drain terminal of the first transistor is connected to the source terminal of the fourth transistor, and the gate terminal of the third transistor is connected to the passive output terminal of the gain-boosting amplifier. The third state of the gain-boosting current mirror is such that the drain terminal of the first transistor is connected to the source terminal of the third transistor, and the gate terminal of the third transistor is connected to the passive output terminal of the gain-boosting amplifier. The fourth state of the gain-boosting current mirror is such that the drain terminal of the first transistor is connected to the source terminal of the third transistor, and the gate terminal of the third transistor is connected to the negative output terminal of the gain-boosting amplifier. Electrochemical sensor detection device based on potentiostat.

6. In paragraph 1, The transimpedance amplifier includes two feedback loops, each having a feedback resistor and a feedback capacitor positioned in parallel, a fourth chopper positioned at one end of the feedback resistor and the feedback capacitor, and a fifth chopper positioned at the other end of the feedback resistor and the feedback capacitor. The fourth and fifth choppers change the feedback loop connection structure between the input or output terminals of the transimpedance amplifier by using the plurality of DEM clock signals. Electrochemical sensor detection device based on potentiostat.

7. In paragraph 1, The digital-to-analog converter includes a resistor and switch array, a digital buffer, a thermometer decoder, and a DEM circuit, and the DEM circuit includes a pseudo-random number generator and a plurality of multiplexers. The above digital-to-analog converter applies a dynamic element matching technique (DEM) using the thermometer decoder and the DEM circuit. Electrochemical sensor detection device based on potentiostat.

8. In paragraph 7, The above thermometer decoder is configured to convert the most significant bit (MSB) into a thermometer code, The above DEM circuit is configured to change the thermometer code into an output code by using selection signals of a plurality of multiplexers input according to a predetermined switching sequence. Electrochemical sensor detection device based on potentiostat.

9. In paragraph 1, The above digital-to-analog converter, A first digital-to-analog converter (DAC) configured to provide the analog signal corresponding to the reference voltage to the transimpedance amplifier; and a first digital-to-analog converter (DAC) configured to provide the analog signal corresponding to the reference voltage to the control amplifier; Electrochemical sensor detection device based on potentiostat.

10. An electrochemical sensor array comprising a plurality of electrochemical sensors; A shift register for selecting one of the plurality of electrochemical sensors using a clock signal; and An electrochemical sensor detection device comprising an electrochemical sensor array and at least one electrode connected thereto, The above electrochemical sensor detection device, A digital-to-analog converter (DAC) configured to receive a digital signal from a waveform generator and digital logic and output an analog signal corresponding to a reference voltage; A gain-boosting current mirror configured to copy the sensor current of each of the plurality of electrochemical sensors and output the sensor copy current; and A transimpedance amplifier configured to convert the above sensor radiation current into a voltage signal; At least one of the above gain-boosting current mirror or the above transimpedance amplifier applies a dynamic element matching technique (DEM) using a plurality of choppers and a plurality of DEM clock signals, The above digital-to-analog converter (DAC) applies the dynamic element matching technique (DEM) using a thermometer decoder and a DEM circuit. A potentiostat-based electrochemical sensor detection system for detecting multi-channel signals.

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