Adaptive readout circuit system and monitoring device for transistor sensors

Abstract

The present disclosure provides an adaptive readout circuit system, including: a signal amplifier, the signal amplifier includes a gain controller, the signal amplifier receives a current output signal of a transistor sensor provided with a bias voltage and a gate voltage, and the signal amplifier generates an amplified voltage signal based on a gain control resistor of the gain controller; a signal processing device, the signal processing device obtains the resistance value of the transistor sensor based on the amplified voltage signal, the bias voltage, the gate voltage and the resistance value of the gain control resistor of the gain controller; the signal processing device determines the size of the amplified voltage signal, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier. The present disclosure also provides a monitoring device.

Description

Technical Field

[0001] The present disclosure relates to the technical field of weak signal readout circuits of controllable gate voltage sensors, and in particular to an adaptive readout circuit system and a monitoring device for field effect transistor sensors. Background Art

[0002] With the development of field-effect transistor sensors based on various materials, the readout circuit system has become increasingly important. It needs to have high reliability, wide range, low power consumption, portability, and real-time detection capabilities. It can be applied to environmental monitoring devices, biomaterial monitoring devices, and medical devices, etc.

[0003] However, due to the diversity of materials and processes, the output resistance range of field effect transistor (FET) sensors is different, and the threshold voltage of transistors of different materials is different, and their resistance values ​​at different gate voltage operating points (linear region, subthreshold region, it is generally believed that sensors in the subthreshold region have higher sensitivity) are also different. Therefore, using sensors made of different materials to detect variables in the same environment requires different readout circuit systems, which greatly reduces the reuse rate of the circuit system. For example, in the environment of detecting hydrogen leaks, researchers use a variety of materials (such as molybdenum disulfide, carbon nanotubes, graphene, etc.) and different processes (PD thickness, sheet shape, channel aspect ratio, etc.) to prepare hydrogen sensors. Their characteristics are different, mainly reflected in the output resistance of the sensor. The output resistance of different materials has several orders of magnitude difference. Therefore, in order to improve the reuse rate of the readout circuit, a wide input current range should be supported.

[0004] In the prior art, gate voltage regulation uses dedicated instruments and equipment, which are bulky and complex in structure and cannot be applied to the preparation of portable / handheld systems.

[0005] For the conventional scheme of weak current (μA level) readout system, a transimpedance amplifier (TIA) is used in the front-end stage, and the voltage output of the TIA is converted into a digital signal by an analog-to-digital converter (ADC), such as Figure 1 Although this solution can be implemented with a simple circuit, the signal collected by the back-end ADC will be inaccurate due to the noise introduced by the power supply and the low-frequency noise introduced by the sensor.

[0006] If a commercial digital potentiometer is used to achieve a wide range, its disadvantage is that the change step length of each multiplication factor is the same. This means that to achieve a wider range of measurements, more resistors are needed, resulting in resource waste and area loss, etc., and commercial digital potentiometers do not have a large range (the maximum is basically 1M-2M, which cannot meet the needs of multi-order magnitude change sensors).

[0007] Since the readout circuit systems designed by researchers are mostly for sensors in their own research direction, the sensor materials and the gain of the amplifier circuit are limited. Because the output resistance of sensors of different materials is different, there will be several orders of magnitude difference. Therefore, the existing circuit systems are only applicable to the sensors specified by the researchers. This makes the scope of use of the circuit system very limited and cannot be supplied to other sensor systems.

[0008] The transistor sensor in the prior art has fixed sensor materials, fixed amplification gain of the amplifier circuit, and has no gate voltage regulation function, which limits the output range of the sensor. In addition, the traditional readout circuit is simple in design and has weak signal noise processing capabilities. The existing readout circuit does not have multiple display terminals, but only has one data display terminal or no display terminal. Summary of the invention

[0009] In order to solve at least one of the above technical problems, the present disclosure provides an adaptive readout circuit system and a monitoring device for a transistor sensor.

[0010] The adaptive readout circuit system and monitoring device for transistor sensors disclosed in the present invention are implemented through the following technical solutions.

[0011] According to one aspect of the present disclosure, there is provided an adaptive readout circuit system, comprising:

[0012] a signal amplifier, the signal amplifier comprising a gain controller, the signal amplifier receiving a current output signal of a transistor sensor provided with a bias voltage and a gate voltage, the signal amplifier generating an amplified voltage signal based on a gain control resistor of the gain controller;

[0013] A signal processing device, wherein the signal processing device obtains a resistance value of the transistor sensor based on the amplified voltage signal, the bias voltage, the gate voltage, and a resistance value of a gain control resistor of the gain controller;

[0014] The signal processing device determines the magnitude of the amplified voltage signal, and based on the determination result, generates or does not generate a control signal for controlling the resistance value of the gain control resistor, so as to adjust or not adjust the signal gain of the signal amplifier.

[0015] According to at least one embodiment of the present disclosure, the adaptive readout circuit system further includes a DAC device, which includes a bias voltage providing module and a gate voltage control module. The bias voltage providing module is used to provide a bias voltage to the transistor sensor, and the gate voltage control module is used to provide a gate voltage to the transistor sensor so that the transistor sensor is in a working area.

[0016] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device includes a DAC module for providing a bias voltage and a gate voltage to the transistor sensor, and based on the gate voltage, the transistor sensor is in an operating region.

[0017] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the gain controller includes:

[0018] A plurality of gain control resistors, each of which has a different resistance value;

[0019] Switchgear;

[0020] A decoder is used to decode a received control signal for controlling the resistance value of the gain control resistor, and generate a switch control signal to control the switch device to connect one of the gain control resistors to the signal amplifier.

[0021] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device determines the magnitude of the amplified voltage signal, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, including:

[0022] When the magnitude of the amplified voltage signal is within a preset voltage value range, the signal processing device generates a control signal for controlling the resistance value of the gain control resistor;

[0023] When the magnitude of the amplified voltage signal is outside the preset voltage value range, the signal processing device does not generate a control signal for controlling the resistance value of the gain control resistor.

[0024] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the switch device includes a plurality of switches, each gain control resistor corresponds to a switch, and each gain control resistor is connected to the signal amplifier or disconnected from the signal amplifier through a corresponding switch.

[0025] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the resistance values ​​of at least two gain control resistors have an order of magnitude difference.

[0026] According to at least one embodiment of the present disclosure, the adaptive readout circuit system further includes a filter, which performs filtering processing on the amplified voltage signal output by the signal amplifier and outputs the filtered amplified voltage signal.

[0027] According to at least one embodiment of the present disclosure, the adaptive readout circuit system further includes an ADC device, which samples the filtered amplified voltage signal to obtain an output voltage value.

[0028] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device determines the size of the output voltage value, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier.

[0029] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, after the signal processing device generates a control signal for controlling the resistance value of the gain control resistor to adjust the signal gain of the signal amplifier, the signal amplifier outputs an amplified voltage signal based on the adjusted signal gain, and the signal processing device obtains the resistance value of the sensor based on the amplified voltage signal, the bias voltage and the resistance value of the gain control resistor of the gain controller.

[0030] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, when the resistance value of the sensor acquired by the signal processing device is equal to or greater than the resistance value of the gain control resistor connected to the signal amplifier, the signal processing device generates a control signal for controlling the resistance value of the gain control resistor.

[0031] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device includes a memory and a processor, the memory stores a program algorithm (first calculation module), and the processor obtains the resistance value of the sensor by executing the program algorithm on the amplified voltage signal (output voltage value), the bias voltage and the resistance value of the gain control resistor of the gain controller.

[0032] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device determines the size of the amplified voltage signal by executing a program algorithm (second calculation module), and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the judgment result, so as to adjust or not adjust the signal gain of the signal amplifier.

[0033] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device includes a memory and a processor, the memory stores a program algorithm (a third computing module), and the processor judges the acquired resistance value of the sensor by executing the program algorithm. When the acquired resistance value of the sensor is equal to or greater than the resistance value of the gain control resistor connected to the signal amplifier, the processor generates a control signal for controlling the resistance value of the gain control resistor.

[0034] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device determines the magnitude of the output voltage value and / or the magnitude of the acquired resistance value of the sensor based on the conversion value of the ADC device.

[0035] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, within a sampling period of the ADC device, the gain controller can controllably connect one of the gain control resistors to the signal amplifier in a manner of increasing resistance value or decreasing resistance value.

[0036] According to at least one embodiment of the present disclosure, the adaptive readout circuit system further includes a display device, which is communicatively connected to the signal processing device to display at least the output voltage value of the ADC device and the acquired resistance value of the sensor.

[0037] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal processing device also includes an encoding module, which converts the control signal generated by the signal processing device for controlling the resistance value of the gain control resistor into a binary control signal to provide to the decoder of the gain controller.

[0038] According to the adaptive readout circuit system of at least one embodiment of the present disclosure, the signal amplifier is a two-stage signal amplifier, and the filter is a two-stage low-pass filter.

[0039] According to another aspect of the present disclosure, there is provided a monitoring device, comprising: a transistor sensor, which monitors a target monitoring signal based on a change in its own resistance value; and an adaptive readout circuit system of any one embodiment of the present disclosure, wherein the adaptive readout circuit system is at least used to obtain a change in the resistance value of the transistor sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0041] Figure 1 It is a schematic diagram of the circuit structure of a transimpedance amplifier in the prior art.

[0042] Figure 2 is a schematic block diagram of the structure of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0043] Figure 3 is a schematic block diagram of the structure of an adaptive readout circuit system according to yet another embodiment of the present disclosure.

[0044] Figure 4 FIG. 4 is a schematic diagram of a circuit structure of a signal amplifier of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0045] Figure 5 FIG. 4 is a schematic diagram of a circuit structure of a signal amplifier of an adaptive readout circuit system according to another embodiment of the present disclosure.

[0046] Figure 6 Schematic diagram of the circuit structure of a gain controller of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0047] Figure 7 FIG. 4 is a schematic diagram of a circuit structure of a filter of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0048] Figure 8 FIG. 4 is a schematic diagram of a circuit structure of a filter of an adaptive readout circuit system according to another embodiment of the present disclosure.

[0049] Fig. 9 Schematic diagram of the circuit structure of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0050] Fig.10 It is the program processing logic of the program algorithm (Algorithms) stored in the signal processing device (MCU) of one embodiment of the present disclosure.

[0051] Fig.11 and Fig.12 The figure shows the process of the sensor's resistance changing as the hydrogen concentration increases.

[0052] Fig.13 The left part of FIG. 1 is the output voltage value and the continuously changing output resistance value of the sensor obtained by continuous sampling for 500 seconds using the readout circuit system of the present disclosure at a hydrogen concentration of 10000 PPM.

[0053] Fig.13 The right part of the graph shows the output voltage value and the continuously changing output resistance value of the sensor obtained by continuous sampling for 500s using a traditional transimpedance amplifier circuit at a hydrogen concentration of 10000PPM. DETAILED DESCRIPTION

[0054] The present disclosure is further described in detail below in conjunction with the accompanying drawings and implementations. It is understood that the specific implementations described herein are only used to explain the relevant content, rather than to limit the present disclosure. It should also be noted that, for ease of description, only the parts related to the present disclosure are shown in the accompanying drawings.

[0055] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure can be combined with each other. The technical solution of the present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0056] Unless otherwise specified, the exemplary embodiments / embodiments shown will be understood as providing exemplary features of various details of some ways in which the technical concept of the present disclosure can be implemented in practice. Therefore, unless otherwise specified, the features of the various embodiments / embodiments can be combined, separated, interchanged and / or rearranged without departing from the technical concept of the present disclosure.

[0057] The use of cross-hatching and / or shading in the accompanying drawings is generally used to make the boundaries between adjacent components clear. As such, unless otherwise specified, the presence or absence of cross-hatching or shading does not convey or indicate any preference or requirement for the specific materials, material properties, dimensions, proportions, commonalities between the components shown, and / or any other characteristics, attributes, properties, etc. of the components. In addition, in the accompanying drawings, the sizes and relative sizes of the components may be exaggerated for clarity and / or descriptive purposes. When the exemplary embodiments can be implemented differently, the specific process sequence can be performed in a different order than described. For example, two successively described processes can be performed substantially simultaneously or in an order opposite to the described order. In addition, the same figure numbers represent the same components.

[0058] When a component is referred to as being "on" or "over," "connected to," or "coupled to" another component, the component may be directly on, directly connected to, or directly coupled to the other component, or intervening components may be present. However, when a component is referred to as being "directly on," "directly connected to," or "directly coupled to" another component, there are no intervening components. For this purpose, the term "connected" may refer to a physical connection, an electrical connection, etc., with or without intervening components.

[0059] For descriptive purposes, the present disclosure may use spatially relative terms such as "under," "beneath," "under," "down," "over," "upper," "above," "higher," and "side (e.g., in a "sidewall")," to describe the relationship of one component to another (other) component as shown in the accompanying drawings. The spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, components described as "under" or "beneath" other components or features would subsequently be positioned "over" the other components or features. Thus, the exemplary term "under" can encompass both the "above" and "below" orientations. Furthermore, the device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0060] The terms used here are for the purpose of describing specific embodiments, and are not intended to be restrictive. As used here, unless the context clearly indicates otherwise, the singular forms "one (kind, person)" and "said (the)" are also intended to include plural forms. In addition, when the terms "comprise" and / or "include" and their variations are used in this specification, it is explained that there are stated features, integral bodies, steps, operations, parts, assemblies and / or their groups, but it is not excluded that there are or add one or more other features, integral bodies, steps, operations, parts, assemblies and / or their groups. It should also be noted that, as used here, the terms "substantially", "approximately" and other similar terms are used as approximate terms and not as degree terms, so that they are used to explain the inherent deviations of the measured values, calculated values ​​and / or the values ​​provided that will be recognized by those of ordinary skill in the art.

[0061] Combined with the following Figures 2 to 13 The adaptive readout circuit system of the present disclosure is described in detail.

[0062] Figure 2 is a schematic block diagram of the structure of an adaptive readout circuit system according to an embodiment of the present disclosure, Figure 3 is a schematic block diagram of the structure of an adaptive readout circuit system according to yet another embodiment of the present disclosure.

[0063] First reference Figure 2 and Figure 3 , the adaptive readout circuit system of the present disclosure comprises:

[0064] The signal amplifier 100 includes a gain controller 110. The signal amplifier 100 receives a bias voltage (V DAC) of the sensor, the signal amplifier 100 generates an amplified voltage signal based on the gain control resistor of the gain controller 110;

[0065] A signal processing device (Microcontroller Unit; MCU) 400, the signal processing device 400 obtains the resistance value of the sensor based on the amplified voltage signal, the bias voltage and the resistance value of the gain control resistor of the gain controller 110;

[0066] The signal processing device 400 determines the magnitude of the amplified voltage signal, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier 100 .

[0067] Among them, the signal processing device 400 of the present disclosure can be an MCU, i.e., a microcontroller unit device. Informed by the technical solution of the present disclosure, those skilled in the art can select or adjust the model of the MCU, etc., which all fall within the protection scope of the present disclosure.

[0068] Compared with the signal amplifier in the prior art (such as Figure 1 As shown), the present disclosure configures the gain controller 110 so that the signal gain (i.e., the signal amplification factor, or the amplification factor) of the signal amplifier 100 can be dynamically adjusted, i.e., adaptively adjusted, based on the output voltage value of the adaptive readout circuit system and the acquired resistance value of the sensor.

[0069] The bias voltage described above is preferably provided by a signal processing device (MCU).

[0070] The signal processing device 400 of the present disclosure may include a bias voltage providing module, preferably capable of providing an adjustable bias voltage.

[0071] The sensor described above in the present disclosure may be a resistive sensor, in particular a field effect transistor type sensor.

[0072] Among them, the field effect transistor sensor can be used as a target gas concentration sensor, such as a hydrogen sensor for detecting hydrogen concentration, such as a CNT-TFT sensor (field effect transistor sensor based on carbon nanotubes), or a molybdenum disulfide sensor, a graphene sensor, etc.

[0073] Those skilled in the art can use the adaptive readout circuit system of the present disclosure to read out signals from various suitable types of sensors, all of which fall within the protection scope of the present disclosure.

[0074] like Figure 2 and Figure 3As shown, the bias voltage and gate voltage of the transistor sensor may be provided by a separate DAC device 500, or a DAC module may be provided in the signal processing device (MCU) 400 to provide the bias voltage and gate voltage to the sensor.

[0075] Taking a three-terminal FET type sensor (having a source, a drain and a gate) as an example, a bias voltage is provided to the drain and the leakage current is detected. The gate voltage can be set to 0V-3.3V, or to a specific voltage according to the sensor performance parameters.

[0076] Transistor sensors with different threshold voltages have different resistance characteristics under different gate voltage regulation.

[0077] The present disclosure can also adjust the gate voltage of the transistor sensor based on the DAC module or DAC device described above to adjust its operating point position, thereby achieving adjustment of the sensitivity of the transistor sensor.

[0078] Different material properties of transistor sensors will result in different output resistance ranges of the sensors. The adaptive readout circuit system disclosed in the present invention can adaptively adjust the resistance value of the gain control resistor of the gain controller 110 based on the acquired resistance value of the sensor and / or the output voltage value of the readout circuit system to achieve continuity detection of the sensor.

[0079] Figure 4 is a schematic diagram of a circuit structure of a signal amplifier 100 of an adaptive readout circuit system according to an embodiment of the present disclosure, Figure 5 FIG. 4 is a schematic diagram of a circuit structure of a signal amplifier 100 of an adaptive readout circuit system according to another embodiment of the present disclosure.

[0080] The present disclosure realizes adaptive adjustment of the signal gain of the signal amplifier 100 by using the gain control resistor of the gain controller 110 as the feedback resistor of the signal amplifier 100 and adjusting the resistance value of the gain control resistor connected to the signal amplifier 100 based on the readout signal of the adaptive readout circuit system (the acquired resistance value and output voltage value of the sensor).

[0081] like Figure 4 and Figure 5 As shown, the sensor resistance R sensor It changes with the concentration of the gas to be detected. If the resistance value of the gain control resistor used as the feedback resistor is not adaptively adjusted, the amplified voltage signal Vout1 / Vout2 may gradually approach 0, and the obtained resistance value may approach infinity, causing the readout circuit system to fail to work properly.

[0082] However, if the resistance value of the gain control resistor used as the feedback resistor is completely linearly controlled based on the resistance change of the sensor, it will increase the difficulty of circuit design and may cause errors in the control logic.

[0083] Figure 4 and Figure 5 In the figure, C1, C2, C3, C4, C5, C6, C7, and C8 are all filter capacitors, and R1 and R3 are both pull-up resistors.

[0084] Figure 5 In the embodiment, R2 and R4 are both set to fixed resistance values, so that the second stage signal amplifier has a stable signal gain.

[0085] It should be noted that Figure 4 The signal amplifier shown in Figure 5 The circuit structures of the signal amplifiers shown in the figure are all circuit structures of the signal amplifiers of the preferred embodiments of the present disclosure. Under the guidance of the technical solutions of the present disclosure, those skilled in the art can Figure 4 and Figure 5 The selection / adjustment of the individual devices in the circuit, or the adjustment of the circuit structure without changing the basic function of the circuit, all fall within the protection scope of the present disclosure.

[0086] The adaptive readout circuit system disclosed in the present invention refers to Figure 2 and Figure 3 , and also includes an ADC device 300, which samples the amplified voltage signal (which may be Vout1 or Vout2) to obtain an output voltage value, namely, the output voltage value of the adaptive readout circuit system.

[0087] According to the preferred embodiment of the present disclosure, still referring to Figure 2 and Figure 3 The adaptive readout circuit system of the present invention further includes a filter 200, which performs filtering processing on the amplified voltage signal (Vout1 / Vout2) output by the signal amplifier 100, and outputs the amplified voltage signal (Vout3 / Vout4) after filtering processing, and the ADC device 300 samples the amplified voltage signal after filtering processing to obtain an output voltage value.

[0088] Figure 7 is a circuit structure diagram of a filter 200 of an adaptive readout circuit system according to an embodiment of the present disclosure, Figure 8 is a circuit structure diagram of a filter 200 of an adaptive readout circuit system according to another embodiment of the present disclosure. Figure 8 The filter 200 in FIG. 2 is a two-stage filter.

[0089] Figure 7 and Figure 8R5, R6, R7, and R8 all have fixed resistance values, and C9 to C20 are filter capacitors. Figure 7 The filter circuit shown in Figure 8 The circuit structures of the filter circuits shown in the figure are all circuit structures of the preferred embodiments of the present disclosure. Under the guidance of the technical solution of the present disclosure, those skilled in the art can Figure 7 and Figure 8 The selection / adjustment of the individual devices in the circuit, or the adjustment of the circuit structure without changing the basic function of the circuit, all fall within the protection scope of the present disclosure.

[0090] The filter 200 of the present disclosure can filter out high-frequency noise in the low-frequency sensor signal to output a stable electrical signal.

[0091] For the adaptive readout circuit system of each of the above embodiments, preferably, the gain controller 110 of the present disclosure includes:

[0092] A plurality of gain control resistors, each gain control resistor having a resistance value different from another;

[0093] Switchgear;

[0094] The decoder (decoding circuit) decodes the received control signal for controlling the resistance value of the gain control resistor, and generates a switch control signal to control the switch device to connect one of the gain control resistors to the signal amplifier 100 .

[0095] The adaptive readout circuit system of this embodiment decodes the received resistance control signal through the decoder of the gain controller 110 to generate a switch control signal. The switch device connects the corresponding gain control resistor to the signal amplifier 100 based on the switch control signal to achieve adaptive control of the signal gain of the signal amplifier 100 based on the size of the amplified voltage signal.

[0096] Figure 6 FIG. 1 is a schematic diagram of a circuit structure of a gain controller 110 of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0097] refer to Figure 6 The gain controller 110 of the present disclosure includes a plurality of gain control resistors ( Figure 6 Six gain control resistors are exemplarily shown in the figure), and these resistors have different resistance values. Based on the switching control signal of the switching device, different gain control resistors can be connected to the signal amplifier 100, thereby realizing the control / adjustment of the resistance value of the gain control resistor in the signal amplifier 100.

[0098] refer to Figure 6The switch device of the gain controller 110 includes a plurality of switches, each gain control resistor corresponds to a switch, and each gain control resistor is connected to the signal amplifier 100 or disconnected from the signal amplifier 100 through a corresponding switch.

[0099] Figure 6 Eight switches (S1-S8) are shown in the figure. Switches S7 and S8 are used for error correction / error detection functions. The remaining six channels (S1-S6) cannot be turned on at the same time. Only one channel is turned on. Different channels can make the signal amplifier 100 have different signal gains (amplification factors).

[0100] According to a preferred embodiment of the present disclosure, in the gain controller 110, resistance values ​​of at least two gain control resistors differ by an order of magnitude.

[0101] Figure 6 In the embodiment, the resistance values ​​of the gain control resistors are 500kΩ, 1MΩ, 3MΩ, 5MΩ, 10MΩ, and 100MΩ, respectively, which can meet the measurement of the sensor resistance changing from 2kΩ to 100MΩ (a change of 5 orders of magnitude). The adaptive readout circuit system disclosed in the present invention can amplify and filter the weak signals of the sensor.

[0102] Inspired by the technical solution of the present disclosure, those skilled in the art can adjust the number and resistance of the gain control resistors, all of which fall within the protection scope of the present disclosure.

[0103] According to an adaptive readout circuit system of an embodiment of the present disclosure, preferably, the signal processing device 400 determines the magnitude of the amplified voltage signal, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, including:

[0104] When the magnitude of the amplified voltage signal is within a preset voltage value range, the signal processing device 400 (MCU) generates a control signal for controlling the resistance value of the gain control resistor;

[0105] When the magnitude of the amplified voltage signal is outside the preset voltage value range, the signal processing device 400 does not generate a control signal for controlling the resistance value of the gain control resistor.

[0106] Preferably, the signal processing device 400 determines the magnitude of the output voltage value of the ADC device 300 , and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier 100 .

[0107] In the adaptive readout circuit system disclosed in the present invention, after the signal processing device 400 generates a control signal for controlling the resistance value of the gain control resistor and adjusts the signal gain of the signal amplifier 100, the signal amplifier 100 outputs an amplified voltage signal based on the adjusted signal gain, and the signal processing device 400 obtains the resistance value of the sensor based on the amplified voltage signal, the bias voltage and the resistance value of the gain control resistor of the gain controller 110.

[0108] The following is a workflow of an adaptive readout circuit system according to one embodiment of the present disclosure.

[0109] Step 1, providing bias voltage and gate voltage to the sensor;

[0110] Step 2: The signal amplifier 100 converts the weak current signal output by the sensor into an amplified voltage signal, and the filter 200 performs filtering on the amplified voltage signal and outputs the filtered amplified voltage signal;

[0111] Step 3, the ADC device 300 collects the voltage signal (amplifies the voltage signal) and generates an output voltage value, and the signal processing device 400 determines whether the output voltage value exceeds a preset voltage value range. The signal acquisition time of the ADC device 300 is set to 500s;

[0112] Step 4: If the voltage exceeds the preset voltage value range, the signal processing device 400 generates a control signal, and the gain controller 110 generates a switch control signal based on the control signal to connect the corresponding gain control resistor to the signal amplifier 100 and continue to detect the current signal of the sensor;

[0113] If the voltage does not exceed the preset voltage value range, the signal processing device 400 does not generate a control signal and continues to detect the current signal of the sensor;

[0114] Step 5, the signal processing device 400 obtains the output resistance value of the sensor by using a program algorithm based on proportional operation to obtain the output voltage value obtained by the ADC device 300;

[0115] Step 6: Display the output resistance value of the sensor and the output voltage value obtained by the ADC device 300 through a display device.

[0116] The required bias voltage can be determined based on the performance parameters of the resistive sensor and provided by a separate DAC device or a DAC module in the signal processing device (MCU) 400 (the bias voltage can be 0 to 3.3 V, for example, the bias voltage required for CNT-FET is 0.1 V).

[0117] The output resistance range of the resistive sensor may be determined according to the output characteristic curve and the transfer curve of the resistive sensor, so that corresponding control logic is configured in the signal processing device 400 to generate a control signal for controlling the resistance value of the gain control resistor.

[0118] If the gain control resistor currently connected to the signal amplifier 100 cannot make the signal gain of the signal amplifier 100 satisfy the resistance value measurement of the resistive sensor, the signal processing device 400 generates a control signal for controlling the resistance value of the gain control resistor.

[0119] According to another preferred embodiment of the adaptive readout circuit system of the present disclosure, when the resistance value of the sensor obtained by the signal processing device 400 is equal to or greater than the resistance value of the gain control resistor connected to the signal amplifier 100, the signal processing device 400 generates a control signal for controlling the resistance value of the gain control resistor.

[0120] For the adaptive readout circuit system of each of the above-mentioned embodiments, preferably, the signal processing device 400 includes a memory and a processor, the memory stores a program algorithm (first calculation module), and the processor obtains the resistance value of the sensor by executing the program algorithm on the amplified voltage signal (output voltage value), the bias voltage and the resistance value of the gain control resistor of the gain controller 110.

[0121] Preferably, the signal processing device 400 determines the size of the amplified voltage signal by executing a program algorithm (second calculation module), and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier 100.

[0122] Preferably, the processor of the signal processing device 400 determines the acquired resistance value of the sensor by executing a program algorithm (the third calculation module). When the acquired resistance value of the sensor is equal to or greater than the resistance value of the gain control resistor connected to the signal amplifier 100, the processor generates a control signal for controlling the resistance value of the gain control resistor to connect a gain control resistor with a larger resistance value to the signal amplifier 100.

[0123] For the adaptive readout circuit system of each of the above embodiments, preferably, the signal processing device 400 determines the magnitude of the output voltage value and / or the magnitude of the acquired resistance value of the sensor based on the conversion value of the ADC device.

[0124] According to a preferred embodiment of the present disclosure, within a sampling period (500s) of the ADC device 300, the gain controller 110 can controllably connect one of the gain control resistors to the signal amplifier 100 in a manner of increasing or decreasing resistance value.

[0125] The “controlled ground” is controlled by the switch control signal.

[0126] Fig. 9 Schematic diagram of the circuit structure of an adaptive readout circuit system according to an embodiment of the present disclosure.

[0127] like Fig. 9 As shown, the signal processing device of the adaptive readout circuit system of the present invention uses an MCU, which includes an encoding module (encoder). The encoding module converts the control signal generated by the signal processing device 400 for controlling the resistance value of the gain control resistor into a binary control signal to provide to the decoder of the gain controller 110.

[0128] Exemplarily, six binary control signals (A2A1A0) are set, which are:

[0129] A2A1A0=000 (set the gain control resistor to 500kΩ);

[0130] A2A1A0=001 (set the gain control resistor to 1MΩ);

[0131] A2A1A0=010 (set the gain control resistor to 3MΩ);

[0132] A2A1A0=011 (set the gain control resistor to 5MΩ);

[0133] A2A1A0=100 (set the gain control resistor to 10MΩ);

[0134] A2A1A0=101 (the resistance value of the gain control resistor is set to 100MΩ).

[0135] The encoder sends a generated binary control signal to the decoder of the gain controller 110, such as Fig. 9 As shown, the decoder has three signal receiving ports (A2, A1, A0). Based on the received binary control signal, the decoder generates a corresponding control signal to control one of switches S1 to S6 to close, thereby connecting a gain control resistor with a corresponding resistance value to the signal amplifier 100.

[0136] According to one embodiment of the present disclosure, the program algorithms stored in the MCU can be executed as follows: Fig.10 The program processing logic shown.

[0137] in, Fig. 9The decoder (decoding circuit) in the embodiment adopts 3-wire to 8-wire decoding. Preferably, in order to meet the current and voltage changes of the driving power supply and avoid the coupling interference between the driving power supply and the driven load, a decoupling capacitor is set at each driving port to prevent the signal noise caused by the driving power supply.

[0138] The present invention tests an adaptive readout circuit system. Taking a hydrogen sensor as an example, the hydrogen sensor is placed in a chamber, a circular outlet is set at the bottom of the chamber, and an airflow control device (MFC, Mass Flow Control) introduces a set hydrogen concentration into the chamber. When the hydrogen sensor contacts the hydrogen filled in the chamber, the hydrogen sensor responds. A communication interface can be set at the top of the cavity, and the readout circuit system of the present invention is connected to the hydrogen sensor through the communication interface.

[0139] Fig.11 and Fig.12 It shows that as the hydrogen concentration increases, the resistance value of the sensor changes continuously, and during the change process, as the resistance gradually increases, the gear of the amplifying resistance is also constantly switched.

[0140] Depend on Fig.11 and Fig.12 It can be clearly seen that the higher the hydrogen concentration, the greater the change in sensor resistance value and the more times the gear is changed.

[0141] For example, at a hydrogen concentration of 200PPM, the default gear (500kΩ) can collect all data; at a hydrogen concentration of 400-1000PPM, the gear was changed twice, and the gear change time was advanced due to the increase in gas concentration; at a high hydrogen concentration of 10000PPM (30000PPM is the hydrogen explosion concentration), the system changed gears four times, and the resistance value changed significantly faster.

[0142] Based on the adaptive readout circuit system disclosed in the present invention, the effect of multi-concentration continuous detection is achieved, and the sensor output resistance changes from the initial 480KΩ (initial value in air) to 9MΩ, completing two orders of magnitude changes. If the hydrogen concentration continues to increase, the readout circuit system can continue to measure a larger output resistance value (upper limit is 100MΩ).

[0143] Fig.13 The left part of FIG. 1 is the output voltage value and the continuously changing output resistance value of the sensor obtained by continuous sampling for 500 seconds using the readout circuit system of the present disclosure at a hydrogen concentration of 10000 PPM.

[0144] Fig.13The right part of the graph shows the output voltage value and the continuously changing output resistance value of the sensor obtained by continuous sampling for 500s using a traditional transimpedance amplifier circuit at a hydrogen concentration of 10000PPM.

[0145] By comparison, it can be seen that when the sensor is continuously sampled using a traditional transimpedance amplifier circuit, if the output resistance of the sensor changes more than the feedback resistance of the transimpedance amplifier circuit, the output voltage collected by the circuit will gradually approach 0, and the sensor resistance calculated by the algorithm will gradually approach infinity, which is obviously not in line with reality. The traditional transimpedance amplifier circuit does not have the function of multi-speed switching, and the amplification factor is fixed. When the signal to be measured is too large to be amplified by the amplification factor, the signal will be output in the form of line negative feedback.

[0146] When the sensor is continuously sampled using the readout circuit system disclosed in the present invention, 500s of sampling can be successfully completed, and the characteristic change curve of the sensor resistance can be observed, which is in line with the actual situation. The readout circuit system disclosed in the present invention can adapt to the change of the sensor output resistance across orders of magnitude, for example, in the example disclosed in the present invention: the sensor output resistance changes from 2KΩ to 100MΩ, achieving a wide dynamic range of 5 orders of magnitude.

[0147] Moreover, if Fig. 9 As shown, the adaptive readout circuit system of the present disclosure can realize real-time monitoring of the output signal by setting a display device (LCD).

[0148] More preferably, the MCU of the adaptive readout circuit system of the present disclosure may also be configured with a wireless communication module so as to at least be able to send the output signal to a portable device such as a mobile phone or a tablet computer.

[0149] According to another aspect of the present disclosure, a monitoring device is provided, comprising: a transistor sensor, which monitors a monitoring target signal (e.g., hydrogen concentration) based on changes in its own resistance value; and an adaptive readout circuit system of any embodiment of the present disclosure, which is at least used to obtain the resistance value of the transistor sensor.

[0150] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0151] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0152] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present disclosure, and are not intended to limit the scope of the present disclosure. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. An adaptive readout circuit system, characterized in that: include: a signal amplifier, the signal amplifier comprising a gain controller, the signal amplifier receiving a current output signal of a transistor sensor provided with a bias voltage and a gate voltage, the signal amplifier generating an amplified voltage signal based on a gain control resistor of the gain controller; as well as A signal processing device, wherein the signal processing device obtains a resistance value of the transistor sensor based on the amplified voltage signal, the bias voltage, the gate voltage, and a resistance value of a gain control resistor of the gain controller; The signal processing device determines the magnitude of the amplified voltage signal, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier; Among them, the signal processing device includes a DAC module, which is used to provide a bias voltage and a gate voltage to the transistor sensor. Based on the gate voltage, the transistor sensor is in a working area, or the adaptive readout circuit system includes a DAC device, and the DAC device includes a bias voltage providing module and a gate voltage control module. The bias voltage providing module is used to provide a bias voltage to the transistor sensor, and the gate voltage control module is used to provide a gate voltage to the transistor sensor so that the transistor sensor is in a working area.

2. The adaptive readout circuit system according to claim 1, characterized in that: The gain controller comprises: A plurality of gain control resistors, each of which has a different resistance value; switchgear; and A decoder is used to decode a received control signal for controlling the resistance value of the gain control resistor, and generate a switch control signal to control the switch device to connect one of the gain control resistors to the signal amplifier.

3. The adaptive readout circuit system according to claim 2, characterized in that: The signal processing device determines the magnitude of the amplified voltage signal, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, including: When the magnitude of the amplified voltage signal is within a preset voltage value range, the signal processing device generates a control signal for controlling the resistance value of the gain control resistor; When the magnitude of the amplified voltage signal is outside the preset voltage value range, the signal processing device does not generate a control signal for controlling the resistance value of the gain control resistor.

4. The adaptive readout circuit system according to claim 2, characterized in that: The switch device includes a plurality of switches, each gain control resistor corresponds to a switch, and each gain control resistor is connected to the signal amplifier or disconnected from the signal amplifier through a corresponding switch.

5. The adaptive readout circuit system according to claim 2, characterized in that: The resistance values ​​of at least two gain control resistors differ by an order of magnitude.

6. The adaptive readout circuit system according to claim 1 or 2, characterized in that: It also includes a filter, which performs filtering processing on the amplified voltage signal output by the signal amplifier and outputs the amplified voltage signal after filtering processing.

7. The adaptive readout circuit system according to claim 6, characterized in that: It also includes an ADC device, which samples the amplified voltage signal after the filtering process to obtain an output voltage value.

8. The adaptive readout circuit system according to claim 7, characterized in that: The signal processing device determines the magnitude of the output voltage value, and based on the determination result, generates or does not generate a control signal for controlling the resistance value of the gain control resistor, so as to adjust or not adjust the signal gain of the signal amplifier.

9. The adaptive readout circuit system according to claim 8, characterized in that: After the signal processing device generates a control signal for controlling the resistance value of the gain control resistor to adjust the signal gain of the signal amplifier, the signal amplifier outputs an amplified voltage signal based on the adjusted signal gain, and the signal processing device obtains the resistance value of the sensor based on the amplified voltage signal, the bias voltage and the resistance value of the gain control resistor of the gain controller.

10. The adaptive readout circuit system according to claim 1, characterized in that: When the resistance value of the sensor acquired by the signal processing device is equal to or greater than the resistance value of the gain control resistor connected to the signal amplifier, the signal processing device generates a control signal for controlling the resistance value of the gain control resistor.

11. The adaptive readout circuit system according to claim 2, characterized in that: The signal processing device includes a memory and a processor, wherein the memory stores a program algorithm, and the processor obtains the resistance value of the sensor by executing the program algorithm on the amplified voltage signal, the bias voltage and the resistance value of the gain control resistor of the gain controller.

12. The adaptive readout circuit system according to claim 11, characterized in that: The signal processing device determines the magnitude of the amplified voltage signal by executing a program algorithm, and generates or does not generate a control signal for controlling the resistance value of the gain control resistor based on the determination result, so as to adjust or not adjust the signal gain of the signal amplifier.

13. The adaptive readout circuit system according to claim 10, characterized in that: The signal processing device includes a memory and a processor, the memory stores a program algorithm, and the processor judges the acquired resistance value of the sensor by executing the program algorithm. When the acquired resistance value of the sensor is equal to or greater than the resistance value of the gain control resistor connected to the signal amplifier, the processor generates a control signal for controlling the resistance value of the gain control resistor.

14. The adaptive readout circuit system according to claim 7, characterized in that: The signal processing device determines the magnitude of the output voltage value and / or the magnitude of the acquired resistance value of the sensor based on the conversion value of the ADC device.

15. The adaptive readout circuit system according to claim 8, characterized in that: In a sampling cycle of the ADC device, the gain controller can be controlled to connect one of the gain control resistors to the signal amplifier in a manner of increasing resistance value or decreasing resistance value.

16. The adaptive readout circuit system according to claim 1, characterized in that: It also includes a display device, which is communicatively connected to the signal processing device to display at least the output voltage value of the ADC device and the acquired resistance value of the sensor.

17. The adaptive readout circuit system according to claim 2, characterized in that: The signal processing device further comprises an encoding module, which converts a control signal generated by the signal processing device and used for controlling the resistance value of the gain control resistor into a binary control signal to provide the binary control signal to a decoder of the gain controller.

18. The adaptive readout circuit system according to claim 6, characterized in that: The signal amplifier is a two-stage signal amplifier, and the filter is a two-stage low-pass filter.

19. A monitoring device, characterized in that: include: A transistor sensor, wherein the transistor sensor monitors a target monitoring signal based on a change in its own resistance value; as well as The adaptive readout circuit system according to any one of claims 1 to 18, wherein the adaptive readout circuit system is used at least to obtain a change in resistance value of a transistor sensor.

Images