An analog front-end integrated circuit applicable to multiple meteorological sensors

Abstract

The present invention relates to the technical fields of meteorological sensors and integrated circuits, and particularly relates to an analog front-end integrated circuit applicable to multiple meteorological sensors, including an external input interface of the chip, peripheral components of the chip, an internal circuit of the chip, a piezoresistive pressure sensor, a capacitive humidity sensor, and a resistive temperature sensor; the present invention can simultaneously collect and condition three meteorological parameters of air pressure, humidity, and temperature, and perform standardized output, and sensors of different models measuring the same meteorological parameter can all perform 0V-5V standardized output, which can meet the requirements of meteorological detection in different scenarios. This integrated circuit adopts a low-power structure, reducing power consumption, simplifying the complexity of circuit design, improving versatility, meeting the modern energy-saving requirements, making the board-level circuit into an integrated circuit, greatly reducing the volume, and facilitating use in various environments.

Description

Technical Field

[0001] The present invention relates to the technical fields of meteorological sensors and integrated circuits, and particularly relates to an analog front-end integrated circuit applicable to multiple meteorological sensors. Background Art

[0002] In recent years, meteorological intelligent sensors have accounted for an increasingly large proportion in people's lives, and multi-sensor microsystems have received extensive attention in meteorological detection. For a sensor application system, sensors and analog front-end circuits are an indispensable part. A variety of sensors are used in meteorological detection. As a measuring device, a meteorological sensor can convert an information that cannot be directly obtained into an electrical signal or other measurable and quantifiable indicators according to a certain sensing mechanism. The vast majority of analog front-end circuits are designed only for a single type of target sensor and have unique functions and uses. Developing an interface circuit for a specific sensor will consume a large amount of time and cost, and its system flexibility and expandability are also greatly limited. The interface circuit for a specific target sensor is only applicable to large-scale and high-cost industrial production. In order to meet the market demand, a comprehensive analog front-end circuit applicable to multiple meteorological sensor platforms should be designed. Therefore, the analog front-end integrated circuit of a composite meteorological sensor has received increasing attention. In 2020, the integrated circuit discipline was separated and became a first-level discipline, and the integrated circuit industry was vigorously supported and developed. The analog front-end integrated circuit of a composite meteorological sensor is a circuit that can simultaneously convert the output signals of multiple meteorological sensors and output them in a standardized manner of 0V - 5V, and output them to the analog-to-digital converter ADC connected to the next stage, which is of great significance for meteorological detection.

[0003] In summary, developing an analog front-end integrated circuit applicable to multiple meteorological sensors is still a key problem that urgently needs to be solved in the technical fields of meteorological sensors and integrated circuits. Summary of the Invention

[0004] To solve the above problems, the present invention provides an analog front-end integrated circuit applicable to multiple meteorological sensors, which can convert the output signals of multiple meteorological sensors and output them in a standardized manner of 0V - 5V. That is, in the pressure conditioning circuit, when the air pressure is 0, the output is 0V, and when the full-scale air pressure is reached, the output is 5V, and the output is given to the ADC connected to the next stage to be converted into a digital signal and then sent to the single-chip microcomputer. In the temperature conditioning circuit, when the temperature is 0, the output is 0V, and when the full-scale temperature is reached, the output is 5V, and the output is given to the ADC connected to the next stage to be converted into a digital signal and then sent to the single-chip microcomputer. The output of the humidity conditioning circuit is a 0V - 5V full-swing square wave signal, which is directly sent to the single-chip microcomputer, and for sensors of different models measuring the same meteorological parameter, 0V - 5V standardized output can be performed, which can meet the requirements of meteorological detection in different scenarios.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides an analog front-end integrated circuit applicable to multiple meteorological sensors, including an external input interface of the chip, peripheral components of the chip, an internal circuit of the chip, a piezoresistive pressure sensor, a capacitive humidity sensor, and a resistive temperature sensor, wherein:

[0007] The external input interface of the chip includes a piezoresistive pressure sensor interface, a capacitive humidity sensor interface, a resistive temperature sensor interface, and an interface for providing an external clock to the analog-to-digital converter in the internal circuit of the chip;

[0008] The peripheral components of the chip include a zero-adjustment resistor and a full-scale adjustment resistor of the pressure sensor conditioning circuit, a duty-cycle control resistor of the humidity sensor conditioning circuit, and a zero-adjustment resistor and a full-scale adjustment resistor of the resistor bridge in the temperature sensor conditioning circuit;

[0009] The internal circuit of the chip includes a low-dropout linear regulator, a pressure sensor conditioning circuit, a humidity sensor conditioning circuit, a temperature sensor conditioning circuit, and an analog-to-digital converter. The input of the low-dropout linear regulator is connected to an external input power supply, and the output is connected to the power input of each module inside the chip. The input of the pressure sensor conditioning circuit is connected to the output of the piezoresistive pressure sensor, and the output is connected to the input of the analog-to-digital converter. The input of the humidity sensor conditioning circuit is connected to the output of the capacitive humidity sensor, and the output is connected to an external single-chip microcomputer. The input of the temperature sensor conditioning circuit is connected to the output of the resistive temperature sensor, the zero-adjustment resistor, and the full-scale adjustment resistor that form a resistor bridge, and the output is connected to the input of the analog-to-digital converter. The inputs of the analog-to-digital converter are respectively connected to the outputs of the pressure sensor conditioning circuit and the temperature sensor conditioning circuit, the clock input is respectively connected to the output of the external clock, the reference voltage input is connected to the reference voltage output of the low-dropout linear regulator, and the output is connected to the external single-chip microcomputer;

[0010] The output of the piezoresistive pressure sensor is connected to the input of the pressure sensor conditioning circuit;

[0011] The output of the capacitive humidity sensor is connected to the input of the humidity sensor conditioning circuit;

[0012] The output of the resistor bridge formed by the resistive temperature sensor, the zero-adjustment resistor, and the full-scale adjustment resistor is connected to the input of the temperature sensor conditioning circuit;

[0013] The clock input port of the analog-to-digital converter is connected to the output of the external clock, and the reference voltage input of the analog-to-digital converter is connected to the reference voltage output of the low-dropout linear regulator.

[0014] A further setting of the present invention is that the piezoresistive pressure sensor converts the air pressure signal into a voltage signal.

[0015] A further setting of the present invention is that the capacitive humidity sensor converts the humidity signal into a capacitance value signal.

[0016] A further setting of the present invention is that the resistive temperature sensor converts the temperature signal into a resistance value signal.

[0017] A further setting of the present invention is that the low-dropout linear regulator stabilizes the external input power supply and outputs it to supply power to all modules inside the chip, and the reference voltage outputs to provide a reference voltage for the analog-to-digital converter.

[0018] A further setting of the present invention is that the pressure sensor conditioning circuit amplifies the output signal of the piezoresistive pressure sensor.

[0019] A further setting of the present invention is that the humidity sensor conditioning circuit converts the capacitance value of the capacitive humidity sensor into a square wave signal with a frequency change and outputs it.

[0020] A further setting of the present invention is that the temperature sensor conditioning circuit amplifies the output signal of the resistance bridge formed by the resistive temperature sensor, the zero-adjusting resistor, and the full-scale adjusting resistor.

[0021] A further setting of the present invention is that the analog-to-digital converter converts the analog signal output by the conditioning circuit into a digital signal and outputs it to the external single-chip microcomputer.

[0022] Beneficial effects

[0023] Adopting the technical solution provided by the present invention, compared with the known public technology, it has the following beneficial effects:

[0024] (1) The present invention can simultaneously collect and condition three meteorological parameters of air pressure, humidity, and temperature, and perform standardized output;

[0025] (2) For the sensors of the same meteorological parameter and different models of the present invention, they can all perform 0V - 5V standardized output, which can meet the requirements of meteorological detection in different scenarios;

[0026] (3) The present invention adopts a low-power consumption structure, reducing the power consumption, simplifying the complexity of the circuit design, improving the versatility, and meeting the modern energy-saving requirements;

[0027] (4) The present invention makes the board-level circuit into an integrated circuit, greatly reducing the volume, having a low cost, and being convenient to use in various environments. Description of the drawings

[0028] Figure 1Schematic diagram of an analog front-end integrated circuit suitable for multiple meteorological sensors according to the present invention;

[0029] Figure 2 Schematic diagram of the low dropout linear regulator (LDO) structure of an analog front-end integrated circuit suitable for multiple meteorological sensors according to the present invention;

[0030] Figure 3 Schematic diagram of the pressure conditioning circuit structure of an analog front-end integrated circuit suitable for multiple meteorological sensors according to the present invention;

[0031] Figure 4 Schematic diagram of the humidity conditioning circuit structure of an analog front-end integrated circuit suitable for multiple meteorological sensors according to the present invention;

[0032] Figure 5 Schematic diagram of the temperature conditioning circuit structure of an analog front-end integrated circuit suitable for multiple meteorological sensors according to the present invention;

[0033] Figure 6 Schematic diagram of the analog-to-digital converter structure of an analog front-end integrated circuit suitable for multiple meteorological sensors according to the present invention. Detailed implementation manners

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "top / bottom end", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "sheathed / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the internal communication of two elements; for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] Embodiment:

[0038] As Figures 1-6 shown, the present invention provides an analog front-end integrated circuit applicable to multiple meteorological sensors, which has a total of 18 ports, namely, a port (VDD) connected to an external power supply, a port (GND) connected to an external ground, ports (V+, V-) connected to the positive and negative ends of a piezoresistive pressure sensor; ports (Z1, Z2) connected to both ends of a zero-adjusting resistor (Rz1); ports (F1, F2) connected to both ends of a full-scale adjusting resistor (Rf1); ports (T1, T2) connected to form a resistor bridge with a resistive temperature sensor and zero-adjusting resistors (Rz2), full-scale adjusting resistors (Rf2, Rf3); a port (H1) connected to the output end of a capacitive humidity sensor; a port (DIS) connected to the middle of duty cycle control resistors (Rh1, Rh2); a port (CO) connected to a filter capacitor (C1); ports (CLK1, CLK2) connected to an external clock; and three output ports (VO1, VO2, VO3).

[0039] The provided analog front-end integrated circuit includes an external input interface of the chip, peripheral components of the chip, an internal circuit of the chip, a piezoresistive pressure sensor, a capacitive humidity sensor, and a resistive temperature sensor, wherein:

[0040] The external input interface of the chip includes a piezoresistive pressure sensor interface (V+, V-), a capacitive humidity sensor interface (H1), a resistive temperature sensor interface (T1, T2), and an interface (CLK1, CLK2) for providing an external clock to analog-to-digital converters (SADC1, SADC2) in the internal circuit of the chip;

[0041] The peripheral components of the chip include a zero-adjusting resistor (Rz1) and a full-scale adjusting resistor (Rf1) of a pressure sensor conditioning circuit, duty cycle control resistors (Rh1, Rh2) of a humidity sensor conditioning circuit, and a zero-adjusting resistor (Rz2) and full-scale adjusting resistors (Rf2, Rf3) of a resistor bridge in a temperature sensor conditioning circuit;

[0042] The internal circuit of the chip includes a low-dropout linear regulator (LDO), a pressure sensor conditioning circuit, a humidity sensor conditioning circuit, a temperature sensor conditioning circuit, and analog-to-digital converters (SADC1, SADC2). The input of the low-dropout linear regulator (LDO) is connected to an external input power supply (VDD), where the voltage of VDD is greater than 5V, such as 6V, and the output is connected to the power input of each module inside the chip (Vldo). The input (V+, V-) of the pressure sensor conditioning circuit is connected to the output (+, -) of the piezoresistive pressure sensor, and the output is connected to the input of the analog-to-digital converter (SADC1) (vo1). It conditions the output signal of the piezoresistive pressure sensor so that the output is 0V at 0 air pressure and 5V at full-scale air pressure, and outputs it to the analog-to-digital converter (SADC1). The output of the capacitive humidity sensor is connected to the input of the humidity sensor conditioning circuit (H1). When the humidity of the external environment changes, the capacitance value of the humidity-sensitive capacitor changes and is output to its conditioning circuit. The input of the humidity sensor conditioning circuit is connected to the output of the capacitive humidity sensor, and the output is connected to an external microcontroller (VO3). It converts the capacitance value of the capacitive humidity sensor into a 0V - 5V full-swing square wave signal with different frequencies and outputs it to the external microcontroller. The input of the temperature sensor conditioning circuit is connected to the output of the resistive temperature sensor and the zero-adjusting resistor and the full-scale adjusting resistor that form a resistance bridge (T1, T2), and the output is connected to the input of the analog-to-digital converter (SADC2) (vo2). It conditions the output signal of the resistance bridge formed by the resistive temperature sensor, the zero-adjusting resistor (Rz2), and the full-scale adjusting resistors (Rf2, Rf3) so that the output is 0V at 0 temperature and 5V at full-scale temperature, and outputs it to the analog-to-digital converter (SADC2). The inputs of the analog-to-digital converters (SADC1, SADC2) are respectively connected to the outputs of the pressure sensor conditioning circuit and the temperature sensor conditioning circuit (vo1, vo2), the clock inputs are respectively connected to the outputs of the external clock, and the reference voltage input is connected to the reference voltage output of the low-dropout linear regulator (Vref). The output is connected to an external microcontroller. It stabilizes the external input power supply, reduces power supply ripple noise, improves the stability of the power supply voltage, and outputs power to all modules inside the chip and provides a reference voltage for the analog-to-digital converters (SADC1, SADC2);

[0043] The output of the piezoresistive pressure sensor is connected to the input of the pressure sensor conditioning circuit;

[0044] The output of the capacitive humidity sensor is connected to the input of the humidity sensor conditioning circuit;

[0045] The output of the resistance bridge formed by the resistive temperature sensor, zero-adjusting resistor (Rz2), and full-scale adjusting resistors (Rf2, Rf3) is connected to the input of the temperature sensor conditioning circuit (T1, T2). When the ambient temperature changes, the resistance value of the thermistor changes, causing the resistance bridge formed by the resistive temperature sensor, zero-adjusting resistor (Rz2), and full-scale adjusting resistors (Rf2, Rf3) to lose balance and generate a voltage difference signal, which is output to its conditioning circuit.

[0046] The clock input ports of the analog-to-digital converters (SADC1, SADC2) are connected to the outputs of the external clocks (CLK1, CLK2), and the reference voltage inputs of the analog-to-digital converters are connected to the reference voltage outputs of the low-dropout linear regulators. The external clocks (CLK1, CLK2) provide accurate clocks for the analog-to-digital converters (SADC1, SADC2) to control the sampling frequency.

[0047] Furthermore, the piezoresistive pressure sensor converts the air pressure signal into a voltage signal.

[0048] Furthermore, the capacitive humidity sensor converts the humidity signal into a capacitance value signal.

[0049] Furthermore, the resistive temperature sensor converts the temperature signal into a resistance value signal.

[0050] Furthermore, the low-dropout linear regulator LDO stabilizes the external input power supply and outputs it to supply power to all modules inside the chip, and the reference voltage outputs the reference voltage to the analog-to-digital converter.

[0051] Furthermore, the pressure sensor conditioning circuit amplifies the output signal of the piezoresistive pressure sensor.

[0052] Furthermore, the humidity sensor conditioning circuit converts the capacitance value of the capacitive humidity sensor into a square wave signal with a frequency change and outputs it.

[0053] Furthermore, the temperature sensor conditioning circuit amplifies the output signal of the resistance bridge formed by the resistive temperature sensor, zero-adjusting resistor, and full-scale adjusting resistors.

[0054] Furthermore, the analog-to-digital converter converts the analog signal output by the conditioning circuit into a digital signal and outputs it to the external microcontroller.

[0055] The present invention can simultaneously collect and condition three meteorological parameters, namely air pressure, humidity, and temperature, and perform standardized output. Moreover, sensors of different models measuring the same meteorological parameter can all perform 0V-5V standardized output, which can meet the requirements of meteorological detection in different scenarios. This integrated circuit adopts a low-power structure, reducing power consumption and the complexity of circuit design, improving versatility, meeting the modern energy-saving requirements. By fabricating the board-level circuit into an integrated circuit, the volume is greatly reduced, facilitating use in various environments.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An analog front-end integrated circuit applicable to multiple meteorological sensors, characterized in that, It includes an external input interface of the chip, peripheral components of the chip, internal circuits of the chip, a piezoresistive pressure sensor, a capacitive humidity sensor, and a resistive temperature sensor, where: The external input interface of the chip includes a piezoresistive pressure sensor interface, a capacitive humidity sensor interface, a resistive temperature sensor interface, and an interface for providing an external clock to the analog-to-digital converter in the internal circuit of the chip; The peripheral components of the chip include a zero-adjustment resistor and a full-scale adjustment resistor of the pressure sensor conditioning circuit, a duty-cycle control resistor of the humidity sensor conditioning circuit, and a zero-adjustment resistor and a full-scale adjustment resistor of the resistor bridge in the temperature sensor conditioning circuit; The internal circuits of the chip include a low-dropout linear regulator, a pressure sensor conditioning circuit, a humidity sensor conditioning circuit, a temperature sensor conditioning circuit, and an analog-to-digital converter. Among them, the analog-to-digital converter includes an analog-to-digital converter SADC1 and an analog-to-digital converter SADC2. The input of the low-dropout linear regulator is connected to an external input power supply, and the output is connected to the power inputs of each module inside the chip. The input of the pressure sensor conditioning circuit is connected to the output of the piezoresistive pressure sensor, and the output is connected to the input of the analog-to-digital converter SADC1. The input of the humidity sensor conditioning circuit is connected to the output of the capacitive humidity sensor, and the output is connected to an external single-chip microcomputer. The input of the temperature sensor conditioning circuit is connected to the output of the resistive temperature sensor and the zero-adjustment resistor and the full-scale adjustment resistor that form a resistor bridge, and the output is connected to the input of the analog-to-digital converter SADC2. The inputs of the analog-to-digital converter are respectively connected to the outputs of the pressure sensor conditioning circuit and the temperature sensor conditioning circuit, the clock input is respectively connected to the output of the external clock, the reference voltage input is connected to the reference voltage output of the low-dropout linear regulator, and the output is connected to the external single-chip microcomputer; The output of the piezoresistive pressure sensor is connected to the input of the pressure sensor conditioning circuit; The output of the capacitive humidity sensor is connected to the input of the humidity sensor conditioning circuit; The output of the resistor bridge formed by the resistive temperature sensor, the zero-adjustment resistor, and the full-scale adjustment resistor is connected to the input of the temperature sensor conditioning circuit; The clock input port of the analog-to-digital converter is connected to the output of the external clock, and the reference voltage input of the analog-to-digital converter is connected to the reference voltage output of the low-dropout linear regulator.

2. The analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, wherein The piezoresistive pressure sensor converts an air pressure signal into a voltage signal.

3. An analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, characterized in that, The capacitive humidity sensor converts a humidity signal into a capacitance value signal.

4. An analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, characterized in that The resistive temperature sensor converts a temperature signal into a resistance value signal.

5. An analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, characterized in that, The low-dropout linear regulator stabilizes the external input power supply and outputs it to supply power to all modules inside the chip, and the reference voltage output provides a reference voltage to the analog-to-digital converter.

6. The analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, wherein The pressure sensor conditioning circuit amplifies the output signal of the piezoresistive pressure sensor.

7. An analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, characterized in that, The humidity sensor conditioning circuit converts the capacitance value of the capacitive humidity sensor into a square wave signal with a frequency change and outputs it.

8. An analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, characterized in that, The temperature sensor conditioning circuit amplifies the output signal of the resistor bridge formed by the resistive temperature sensor and the zero-adjustment resistor and the full-scale adjustment resistor.

9. An analog front-end integrated circuit applicable to multiple meteorological sensors according to claim 1, characterized in that, The analog-to-digital converter converts the analog signal output by the conditioning circuit into a digital signal and outputs it to an external single-chip microcomputer.

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