Sensor circuit applied to range hood and range hood thereof

Abstract

The present invention discloses a sensor circuit applied to a smoke machine, which includes a zeroing infrared receiving module, a detection infrared receiving module, a differential amplification module, an A / D acquisition module, a processor and a temperature acquisition module; the zeroing infrared receiving module and the detection infrared receiving module are connected to the processor through the differential amplification module and the A / D acquisition module in turn, and the processor is also connected to the temperature acquisition module; the temperature acquisition module is arranged near the detection infrared receiving module, and is used to collect the ambient temperature of the detection infrared receiving module; the performance of the zeroing infrared receiving module and the detection infrared receiving module are similar or the same; the differential amplification module includes a differential amplification circuit, which is used to offset the changes in the electrical signals received by the zeroing infrared receiving module and the detection infrared receiving module generated by the environment. The present invention can realize the automatic zero adjustment of the circuit itself when the ambient light or temperature changes, reduce the deviation of the circuit output signal, and accurately reflect the detection concentration.

Description

Technical Field

[0001] The invention belongs to the technical field of range hood control circuits, and in particular relates to a sensor circuit applied to a range hood and the range hood thereof. Background Art

[0002] Traditional zeroing circuits usually use fixed zeroing, which is not enough for infrared receiving tubes that are affected by ambient light and ambient temperature. Different ambient light and ambient temperature will affect the infrared receiving tube's output of different currents, making the fixed zeroing method meaningless. When the infrared receiving tube is affected by ambient light and ambient temperature, the infrared receiving tube's detection range for oil smoke concentration will be reduced, making it unable to reach the proper detection range, thus affecting the detection effect. Summary of the invention

[0003] In view of this, the main purpose of the present invention is to provide a sensor circuit applied to a range hood.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] The embodiment of the present invention provides a sensor circuit applied to a smoke machine, which includes a zeroing infrared receiving module, a detection infrared receiving module, a differential amplification module, an A / D acquisition module, a temperature acquisition module and a processor;

[0006] The zeroing infrared receiving module is connected to the differential amplifier module, and is used to collect the ambient light and ambient temperature of the current environment and output a first electrical signal to the differential amplifier module;

[0007] The detection infrared receiving module is connected to the differential amplifier module, and is used to collect the ambient light and ambient temperature of the current environment and output a second electrical signal to the differential amplifier module;

[0008] The input end of the differential amplifier module is respectively connected to the zeroing infrared receiving module and the detection infrared receiving module to play an automatic zeroing role, and the output end is connected to the A / D acquisition module to respectively receive the first electrical signal and the second electrical signal sent by the zeroing infrared receiving module and the detection infrared receiving module, and generate a target signal according to the first electrical signal and the second electrical signal, and output the target signal to the A / D acquisition module;

[0009] The input end of the A / D acquisition module is connected to the differential amplifier module, and the output end is connected to the A / D acquisition module, and is used to convert the target signal and output it to the processor;

[0010] The temperature acquisition module is connected to the processor and is used to collect and detect the ambient temperature of the infrared receiving module and output it to the processor;

[0011] The processor is connected to the A / D acquisition module and the temperature acquisition module respectively, and is used to generate a control signal according to the converted target signal and the ambient temperature, and automatically zero the zeroing infrared receiving module and the detection infrared receiving module;

[0012] In the above scheme, the zeroing infrared receiving module includes a zeroing infrared receiving tube J2, a fourth resistor R4, and a fifteenth resistor R15. One end of the zeroing infrared receiving tube J2 is connected to the power supply, one end of the other end is connected to the differential amplifier module through the fourth resistor R4, and the other end is grounded through the fifteenth resistor R15.

[0013] In the above scheme, the detection infrared receiving module includes a detection infrared receiving tube J1, a second resistor R2, and a first resistor R1. One end of the detection infrared receiving tube J1 is connected to the power supply, one end of the other end is connected to the differential amplifier module through the second resistor R2, and the other end is grounded through the first resistor R1.

[0014] In the above solution, the differential amplifier module includes a secondary differential amplifier circuit, a third resistor R3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9;

[0015] The first negative input terminal of the secondary differential amplifier circuit is connected to the zeroing infrared receiving module, the first positive input terminal is connected to the detection infrared receiving module, the first output terminal is connected to the second positive input terminal through the sixth resistor R6, a fifth resistor R5 is further connected between the first negative input terminal and the first output terminal, and the first positive input terminal is further grounded through the third resistor R3;

[0016] One of the second negative input terminals of the secondary differential amplifier circuit is connected to the second output terminal through the seventh resistor R7, and the other is grounded through the ninth resistor R9. The second output terminal and the seventh resistor R7 are connected to the processor through the eighth resistor R8.

[0017] In the above scheme, the differential amplifier module also includes a voltage follower U3A connected between the zero-adjusting infrared receiving module and the secondary differential amplifier circuit, and a voltage follower U3B connected between the detection infrared receiving module and the secondary differential amplifier circuit; the voltage follower U3A is connected to the differential amplifier module through a fourth resistor R4, and the voltage follower U3B is connected to the differential amplifier module through a second resistor R2.

[0018] In the above solution, the differential amplifier module includes a secondary conventional amplifier circuit, a differential amplifier circuit, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and an eighth resistor R8;

[0019] The first negative input terminal of the secondary conventional amplifier circuit is connected to the second negative input terminal through the resistor RG, the first positive input terminal is connected to the detection infrared receiving module, the first output terminal is connected to the positive input terminal of the differential amplifier circuit through the fourth resistor R4, and the third resistor R3 is also connected between the first output terminal and the first negative input terminal;

[0020] The second positive input terminal of the secondary conventional amplifier circuit is connected to the zero-adjusting infrared receiving module, the second output terminal is connected to the negative input terminal of the differential amplifier circuit through the sixth resistor R6, and the second negative input terminal and the second output terminal are connected to the fifth resistor R5;

[0021] The positive input terminal of the differential amplifier circuit is grounded via an eighth resistor R8, the negative input terminal is connected to the processor via a seventh resistor R7, and the output terminal is connected to the processor.

[0022] In the above solution, the temperature acquisition module includes a thermistor RZ and a tenth resistor R10;

[0023] One end of the thermistor RZ is connected to a power source, and the other end is grounded via a tenth resistor R10 . A processor is connected between the thermistor RZ and the tenth resistor R10 .

[0024] In the above scheme, the processor includes a chip U1, a burning module, and a serial communication module. The burning module and the serial communication module are both connected to the chip U1. The 9th terminal of the chip U1 is connected to the power supply, the 10th terminal is grounded, the 2nd terminal is connected to the temperature acquisition module, and the 20th terminal is connected to the differential amplifier module.

[0025] In the above solution, the serial communication module includes a serial communication module CN2, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, and a second capacitor C2;

[0026] The first terminal of the serial communication module CN2 is connected to a power supply, the second terminal outputs an RX signal through a thirteenth resistor R13, the third terminal outputs a TX signal through a fourteenth resistor R14, the fourth terminal is grounded, a first capacitor C1 is connected in parallel between the second terminal and the fourth terminal, and a second capacitor C2 is connected in parallel between the third terminal and the fourth terminal.

[0027] A range hood, characterized in that it comprises a range hood body, a range hood turbine and a sensor circuit applied to the range hood as in the above scheme, wherein the range hood turbine is arranged on the range hood body, and a detection infrared receiving module in the sensor circuit is arranged at an air inlet at an edge of the range hood turbine.

[0028] Compared with the prior art, the sensor circuit provided by the present invention and applied to the range hood can realize automatic zero adjustment of the circuit itself when the ambient light or temperature changes, thereby reducing the deviation of the circuit output signal and accurately reflecting the detection concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A connection block diagram of a sensor circuit applied to a range hood provided by an embodiment of the present invention;

[0030] Figure 2 A circuit diagram of a sensor circuit applied to a range hood provided in Embodiment 1 of the present invention;

[0031] Figure 3 A circuit diagram of a sensor circuit applied to a range hood provided in Embodiment 2 of the present invention;

[0032] Figure 4 A circuit diagram of a sensor circuit applied to a range hood provided in Embodiment 3 of the present invention;

[0033] Figure 5 A schematic diagram of the structure of detecting the position of an infrared receiving module on a range hood in a sensor circuit applied to a range hood provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] The embodiment of the present invention provides a sensor circuit applied to a range hood, such as Figure 1 As shown, it includes a zeroing infrared receiving module 1, a detection infrared receiving module 2, a differential amplification module 3, an A / D acquisition module 4, a temperature acquisition module 5 and a processor 6;

[0036] The zeroing infrared receiving module 1 is connected to the differential amplifier module 3, and is used to collect the ambient light and ambient temperature of the current environment and output a first electrical signal to the differential amplifier module 3;

[0037] The detection infrared receiving module 2 is connected to the differential amplifier module 3, and is used to collect the ambient light and ambient temperature of the current environment and output a second electrical signal to the differential amplifier module 3;

[0038] The input end of the differential amplifier module 3 is connected to the zeroing infrared receiving module 1 and the detection infrared receiving module 2 respectively, and the output end is connected to the A / D acquisition module 4, for receiving the first electrical signal and the second electrical signal sent by the zeroing infrared receiving module 1 and the detection infrared receiving module 2 respectively, generating a target signal according to the first electrical signal and the second electrical signal, and outputting the target signal to the A / D acquisition module 4;

[0039] The input end of the A / D acquisition module 4 is connected to the differential amplifier module 3, and the output end is connected to the A / D acquisition module 4, and is used to convert the target signal and output it to the processor 6;

[0040] The temperature acquisition module 5 is connected to the processor 6 and is used to collect and detect the ambient temperature of the infrared receiving module 2 and output it to the processor 6;

[0041] The processor 6 is connected to the A / D acquisition module 4 and the temperature acquisition module 5 respectively, and is used to generate a control signal according to the converted target signal and the ambient temperature, and automatically zero the zeroing infrared receiving module 1 and the detection infrared receiving module 2.

[0042] In the above scheme, the zeroing infrared receiving module 1 includes a zeroing infrared receiving tube J2, a fourth resistor R4, and a fifteenth resistor R15. One end of the zeroing infrared receiving tube J2 is connected to the power supply, one end of the other end is connected to the differential amplifier module 3 through the fourth resistor R4, and the other end is grounded through the fifteenth resistor R15.

[0043] In the above scheme, the detection infrared receiving module 2 includes a detection infrared receiving tube J1, a second resistor R2, and a first resistor R1. One end of the detection infrared receiving tube J1 is connected to the power supply, one end of the other end is connected to the differential amplifier module 3 through the second resistor R2, and the other end is grounded through the first resistor R1.

[0044] In the above solution, the differential amplifier module 3 includes a secondary differential amplifier circuit, a sixth resistor R6, a fifth resistor R5, a third resistor R3, a seventh resistor R7, a ninth resistor R9, and an eighth resistor R8;

[0045] The first negative input terminal of the secondary differential amplifier circuit is connected to the zeroing infrared receiving module 1, the first positive input terminal is connected to the detection infrared receiving module 2, the first output terminal is connected to the second positive input terminal through the sixth resistor R6, a fifth resistor R5 is further connected between the first negative input terminal and the first output terminal, and the first positive input terminal is further grounded through the third resistor R3;

[0046] One of the second negative input terminals of the secondary differential amplifier circuit is connected to the second output terminal through the seventh resistor R7, and the other is grounded through the ninth resistor R9. The second output terminal and the seventh resistor R7 are connected to the processor 6 through the eighth resistor R8.

[0047] In the above scheme, the differential amplifier module 3 also includes a voltage follower U3A connected between the zero-adjusting infrared receiving module 1 and the secondary differential amplifier circuit, and a voltage follower U3B connected between the detection infrared receiving module 2 and the secondary differential amplifier circuit; the voltage follower U3A is connected to the differential amplifier module 3 through the fourth resistor R4, and the voltage follower U3B is connected to the differential amplifier module 3 through the second resistor R2.

[0048] In the above scheme, the differential amplifier module 3 includes a secondary conventional amplifier circuit, a differential amplifier circuit, a fourth resistor R4, a third resistor R3, a sixth resistor R6, a fifth resistor R5, and an eighth resistor R8;

[0049] The first negative input terminal of the secondary conventional amplifier circuit is connected to the second negative input terminal through the resistor RG, the first positive input terminal is connected to the detection infrared receiving module 2, the first output terminal is connected to the positive input terminal of the differential amplifier circuit through the fourth resistor R4, and the third resistor R3 is also connected between the first output terminal and the first negative input terminal;

[0050] The second positive input terminal of the secondary conventional amplifier circuit is connected to the zeroing infrared receiving module 1, the second output terminal is connected to the negative input terminal of the differential amplifier circuit through the sixth resistor R6, and the second negative input terminal and the second output terminal are connected to the fifth resistor R5;

[0051] The positive input terminal of the differential amplifier circuit is grounded via an eighth resistor R8 , the negative input terminal is connected to the processor 6 via a seventh resistor R7 , and the output terminal is connected to the processor 6 .

[0052] In the above solution, the temperature acquisition module 5 includes a thermistor RZ and a tenth resistor R10;

[0053] One end of the thermistor RZ is connected to a power source, and the other end is grounded via a tenth resistor R10 . A processor 6 is connected between the thermistor RZ and the tenth resistor R10 .

[0054] In the above scheme, the processor 6 includes a chip U1, a burning module, and a serial communication module. The burning module and the serial communication module are both connected to the chip U1. The 9th terminal of the chip U1 is connected to the power supply, the 10th terminal is grounded, the 2nd terminal is connected to the temperature acquisition module 5, and the 20th terminal is connected to the differential amplifier module 3.

[0055] In the above solution, the serial communication module includes a serial communication module CN2, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, and a second capacitor C2;

[0056] The first terminal of the serial communication module CN2 is connected to a power supply, the second terminal outputs an RX signal through a thirteenth resistor R13, the third terminal outputs a TX signal through a fourteenth resistor R14, the fourth terminal is grounded, a first capacitor C1 is connected in parallel between the second terminal and the fourth terminal, and a second capacitor C2 is connected in parallel between the third terminal and the fourth terminal.

[0057] A range hood, comprising a range hood body 7, a range hood turbine 8 and a sensor circuit used in the range hood in the above solution, wherein the range hood body 7 is provided with the range hood turbine 8, and the edge of the range hood turbine 8 is provided with the detection infrared receiving module 2 in the sensor circuit. Figure 5 shown.

[0058] The differential amplifier circuit module 3 adopts operational differential amplifier or differential amplifier chip to realize signal amplification and zero adjustment.

[0059] The A / D acquisition module 4 is an A / D acquisition chip or an A / D acquisition pin integrated in the processor itself; the A / D acquisition chip acquires voltage and transmits it to the processor 6 through a communication protocol.

[0060] The processor 6 is a single chip microcomputer, and the brand of the single chip microcomputer is Renesas, STM32, PIC, AVR or Freescale.

[0061] The automatic zeroing function utilizes infrared receiving tubes with similar or identical performance. The two infrared receiving tubes are simultaneously connected to the differential amplifier module 3. When the ambient light or temperature changes, since the two infrared receiving tubes have the same impact on the environment, the changes in the electrical signals generated by the environment on the two tubes can offset each other in the differential amplifier module 3, so that the circuit output signal is restored to the target value to achieve the purpose of zeroing.

[0062] Under different ambient temperatures, the sensitivity curve of the infrared receiving tube will also be different; the temperature near the infrared receiving tube is collected by the temperature sensor next to the infrared receiving tube, and then the processor uses the infrared receiving sensitivity curve under different temperature conditions to identify the oil smoke concentration corresponding to the signal at this time.

[0063] The double infrared tube zeroing circuit is a temperature drift zeroing circuit. The zeroing infrared receiving module is wrapped by a material with infrared shielding function or the zeroing infrared tube is placed in a compartment with infrared shielding function.

[0064] Example 1

[0065] This embodiment 1 provides a sensor circuit applied to a range hood, such as Figure 3As shown, it includes a zeroing infrared receiving tube J2, a fourth resistor R4, a fifteenth resistor R15, a detection infrared receiving tube J1, a second resistor R2, a first resistor R1, a secondary differential amplifier circuit, a sixth resistor R6, a fifth resistor R5, a third resistor R3, a seventh resistor R7, a ninth resistor R9, an eighth resistor R8, a thermistor RZ, a tenth resistor R10, a chip U1, a burning module, a serial communication module CN2, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, and a second capacitor C2;

[0066] One end of the zero-adjusting infrared receiving tube J2 is connected to the power supply, one end of the other end is connected to the secondary differential amplifier circuit through the fourth resistor R4, and the other end is grounded through the fifteenth resistor R15;

[0067] One end of the detection infrared receiving tube J1 is connected to the power supply, one end of the other end is connected to the secondary differential amplifier circuit through the second resistor R2, and the other end is grounded through the first resistor R1;

[0068] The first negative input terminal of the secondary differential amplifier circuit is connected to the zeroing infrared receiving tube J2, the first positive input terminal is connected to the detection infrared receiving tube J1, the first output terminal is connected to the second positive input terminal through the sixth resistor R6, a fifth resistor R5 is further connected between the first negative input terminal and the first output terminal, and the first positive input terminal is further grounded through the third resistor R3;

[0069] One of the second negative input terminals of the secondary differential amplifier circuit is connected to the second output terminal through the seventh resistor R7, and the other is grounded through the ninth resistor R9. The second output terminal and the seventh resistor R7 are connected to the 20th terminal of the chip U1 through the eighth resistor R8.

[0070] One end of the thermistor RZ is connected to the power supply, and the other end is grounded via the tenth resistor R10, and the second end of the chip U1 is connected between the thermistor RZ and the tenth resistor R10;

[0071] The burning module and the serial communication module CN2 are both connected to the chip U1. The 9th terminal of the chip U1 is connected to the power supply, the 10th terminal is grounded, the 2nd terminal is connected to the thermistor RZ, the 20th terminal is connected to the second output terminal of the secondary differential amplifier circuit, and the 11th and 12th terminals are connected to the serial communication module CN2;

[0072] The first terminal of the serial communication module CN2 is connected to a power supply, the second terminal outputs an RX signal through a thirteenth resistor R13, the third terminal outputs a TX signal through a fourteenth resistor R14, the fourth terminal is grounded, a first capacitor C1 is connected in parallel between the second terminal and the fourth terminal, and a second capacitor C2 is connected in parallel between the third terminal and the fourth terminal.

[0073] The automatic zero adjustment function is realized based on the differential amplifier circuit. The differential amplifier circuit formula is:

[0074] No reserved resistor R3

[0075] There is a reserved resistor R3

[0076] Among them, R4=R2, R5=R3, R15=R1;

[0077] U0 is the output voltage, U1 is the detection infrared tube signal voltage, and U2 is the zero adjustment voltage of the zero adjustment infrared tube; the formula without reserved resistance is applicable to the current where the reserved resistance cannot be ignored, and the formula with reserved resistance is applicable to the current where the reserved resistance can be ignored.

[0078] When the ambient light and ambient temperature change, the U1 and U2 of the infrared tube will increase or decrease at the same time. The initial value is near 0, which eventually makes the initial value of U0 have little deviation, so as to achieve the purpose of automatic zeroing.

[0079] Example 2

[0080] This embodiment 2 provides a sensor circuit applied to a range hood, such as Figure 4 As shown, it includes a zeroing infrared receiving tube J2, a fourth resistor R4, a fifteenth resistor R15, a detection infrared receiving tube J1, a second resistor R2, a first resistor R1, a secondary differential amplifier circuit, a sixth resistor R6, a fifth resistor R5, a third resistor R3, a seventh resistor R7, a ninth resistor R9, an eighth resistor R8, a voltage follower U3A, a voltage follower U3B, a thermistor RZ, a tenth resistor R10, a chip U1, a burning module, a serial communication module CN2, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, and a second capacitor C2;

[0081] One end of the zero-adjusting infrared receiving tube J2 is connected to the power supply, one end of the other end is connected to the secondary differential amplifier circuit through the voltage follower U3A and the fourth resistor R4 in sequence, and the other end is grounded through the fifteenth resistor R15;

[0082] One end of the detection infrared receiving tube J1 is connected to the power supply, one end of the other end is connected to the secondary differential amplifier circuit through the voltage follower U3B and the second resistor R2 in sequence, and the other end is grounded through the first resistor R1;

[0083] The first negative input terminal of the secondary differential amplifier circuit is connected to the zeroing infrared receiving tube J2, the first positive input terminal is connected to the detection infrared receiving tube J1, the first output terminal is connected to the second positive input terminal through the sixth resistor R6, a fifth resistor R5 is further connected between the first negative input terminal and the first output terminal, and the first positive input terminal is further grounded through the third resistor R3;

[0084] One of the second negative input terminals of the secondary differential amplifier circuit is connected to the second output terminal through the seventh resistor R7, and the other is grounded through the ninth resistor R9. The second output terminal and the seventh resistor R7 are connected to the 20th terminal of the chip U1 through the eighth resistor R8.

[0085] One end of the thermistor RZ is connected to the power supply, and the other end is grounded via the tenth resistor R10, and the second end of the chip U1 is connected between the thermistor RZ and the tenth resistor R10;

[0086] The burning module and the serial communication module CN2 are both connected to the chip U1. The 9th terminal of the chip U1 is connected to the power supply, the 10th terminal is grounded, the 2nd terminal is connected to the thermistor RZ, the 20th terminal is connected to the second output terminal of the secondary differential amplifier circuit, and the 11th and 12th terminals are connected to the serial communication module CN2;

[0087] The first terminal of the serial communication module CN2 is connected to a power supply, the second terminal outputs an RX signal through a thirteenth resistor R13, the third terminal outputs a TX signal through a fourteenth resistor R14, the fourth terminal is grounded, a first capacitor C1 is connected in parallel between the second terminal and the fourth terminal, and a second capacitor C2 is connected in parallel between the third terminal and the fourth terminal.

[0088] The measured signal is introduced into a two-stage amplifier circuit through a voltage follower, the first stage is differential amplification, and the second stage is conventional voltage amplification.

[0089] The automatic zero adjustment function is realized based on the differential amplifier circuit. The differential amplifier circuit formula is:

[0090]

[0091] Among them, R4=R2, R5=R3, R15=R1;

[0092] U0 is the output voltage, U1 is the detection infrared tube signal voltage, and U2 is the zeroing voltage of the zeroing infrared tube;

[0093] When the ambient light and ambient temperature change, the U1 and U2 of the infrared tube will increase or decrease at the same time. The initial value is near 0, which eventually makes the initial value of U0 have little deviation, so as to achieve the purpose of automatic zeroing.

[0094] Example 3

[0095] This embodiment 1 provides a sensor circuit applied to a range hood, such as Figure 5As shown, it includes a zeroing infrared receiving tube J2, a fourth resistor R4, a fifteenth resistor R15, a detection infrared receiving tube J1, a second resistor R2, a first resistor R1, a secondary conventional amplifier circuit, a differential amplifier circuit, a fourth resistor R4, a third resistor R3, a sixth resistor R6, a fifth resistor R5, an eighth resistor R8, a thermistor RZ, a tenth resistor R10, a chip U1, a burning module, a serial communication module CN2, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, and a second capacitor C2;

[0096] One end of the zero-adjusting infrared receiving tube J2 is connected to the power supply, one end of the other end is connected to the secondary differential amplifier circuit through the fourth resistor R4, and the other end is grounded through the fifteenth resistor R15;

[0097] One end of the detection infrared receiving tube J1 is connected to the power supply, one end of the other end is connected to the secondary differential amplifier circuit through the second resistor R2, and the other end is grounded through the first resistor R1;

[0098] The first negative input terminal of the secondary conventional amplifier circuit is connected to the second negative input terminal through the resistor RG, the first positive input terminal is connected to the detection infrared receiving tube J1, the first output terminal is connected to the positive input terminal of the differential amplifier circuit through the fourth resistor R4, and the third resistor R3 is also connected between the first output terminal and the first negative input terminal;

[0099] The second positive input terminal of the secondary conventional amplifier circuit is connected to the zero-adjusting infrared receiving tube J2, the second output terminal is connected to the negative input terminal of the differential amplifier circuit through the sixth resistor R6, and the second negative input terminal and the second output terminal are connected to the fifth resistor R5;

[0100] The positive input terminal of the differential amplifier circuit is grounded through an eighth resistor R8, the negative input terminal is connected to the 20th terminal of the chip U1 through a seventh resistor R7, and the output terminal is connected to the 20th terminal of the chip U1;

[0101] One end of the thermistor RZ is connected to the power supply, and the other end is grounded via the tenth resistor R10, and the second end of the chip U1 is connected between the thermistor RZ and the tenth resistor R10;

[0102] The burning module and the serial communication module CN2 are both connected to the chip U1. The 9th terminal of the chip U1 is connected to the power supply, the 10th terminal is grounded, the 2nd terminal is connected to the thermistor RZ, the 20th terminal is connected to the output terminal of the differential amplifier circuit, and the 11th and 12th terminals are connected to the serial communication module CN2;

[0103] The first end of the serial communication module CN2 is connected to a power supply, the second end outputs an RX signal through a thirteenth resistor R13, the third end outputs a TX signal through a fourteenth resistor R14 and is connected to the corresponding end of the chip U1, the fourth end is grounded, a first capacitor C1 is connected in parallel between the second end and the fourth end, and a second capacitor C2 is connected in parallel between the third end and the fourth end.

[0104] That is, the amplifier circuit of this embodiment 3 adopts a three-op-amp instrument amplifier circuit. One end of the differential amplifier circuit is connected to the power supply, and the other end is grounded;

[0105] The automatic zeroing function is realized based on the three-op-amp instrument circuit. The formula of the three-op-amp instrument amplifier circuit is:

[0106]

[0107] Among them, R3=R5, R4=R6, R8=R7, R15=R1;

[0108] U0 is the output voltage, U1 is the infrared tube detection signal voltage, and U2 is the zeroing voltage of the infrared tube. When the ambient light and ambient temperature change, U1 and U2 of the infrared tube will increase or decrease at the same time, making the initial value of (U1-U2) close to 0, and finally making the initial value of U0 close to 0, so as to achieve the purpose of automatic zeroing.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A sensor circuit used in a range hood, characterized in that: It comprises a zeroing infrared receiving module (1), a detecting infrared receiving module (2), a differential amplification module (3), an A / D acquisition module (4), a temperature acquisition module (5) and a processor (6); The zeroing infrared receiving module (1) is connected to the differential amplification module (3) and is used to collect ambient light and ambient temperature of the current environment and output a first electrical signal to the differential amplification module (3); The detection infrared receiving module (2) is connected to the differential amplification module (3) and is used to collect ambient light and ambient temperature of the current environment and output a second electrical signal to the differential amplification module (3); The input end of the differential amplifier module (3) is respectively connected to the zeroing infrared receiving module (1) and the detection infrared receiving module (2) to achieve automatic zeroing, and the output end is connected to the A / D acquisition module (4) to respectively receive the first electrical signal and the second electrical signal sent by the zeroing infrared receiving module (1) and the detection infrared receiving module (2), and to generate a target signal according to the first electrical signal and the second electrical signal, and output the target signal to the A / D acquisition module (4); The input end of the A / D acquisition module (4) is connected to the differential amplifier module (3), and the output end is connected to the A / D acquisition module (4), and is used to convert the target signal and output it to the processor (6); The temperature acquisition module (5) is connected to the processor (6) and is used to collect and detect the ambient temperature of the infrared receiving module (2) and output it to the processor (6); The processor (6) is connected to the A / D acquisition module (4) and the temperature acquisition module (5) respectively, and is used to generate a control signal according to the converted target signal and the ambient temperature, and automatically zero the zeroing infrared receiving module 1 and the detection infrared receiving module 2; the zeroing infrared receiving module (1) comprises a zeroing infrared receiving tube J2, a fourth resistor R4, and a fifteenth resistor R15; one end of the zeroing infrared receiving tube J2 is connected to a power supply, one end of the other end is connected to the differential amplifier module (3) through the fourth resistor R4, and the other end is grounded through the fifteenth resistor R15; the zeroing infrared receiving module (1) is wrapped by a material having infrared shielding properties, or the zeroing infrared tube is placed in a compartment that shields infrared properties.

2. The sensor circuit used in a range hood according to claim 1, characterized in that: The detection infrared receiving module (2) comprises a detection infrared receiving tube J1, a second resistor R2, and a first resistor R1; one end of the detection infrared receiving tube J1 is connected to a power supply, one end of the other end is connected to a differential amplifier module (3) through the second resistor R2, and the other end is grounded through the first resistor R1.

3. The sensor circuit used in a range hood according to claim 1, characterized in that: The differential amplifier module (3) comprises a secondary differential amplifier circuit, a third resistor R3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9; The first negative input terminal of the secondary differential amplifier circuit is connected to the zeroing infrared receiving module (1), the first positive input terminal is connected to the detecting infrared receiving module (2), the first output terminal is connected to the second positive input terminal via a sixth resistor R6, a fifth resistor R5 is further connected between the first negative input terminal and the first output terminal, and the first positive input terminal is further grounded via a third resistor R3; One of the second negative input terminals of the secondary differential amplifier circuit is connected to the second output terminal through a seventh resistor R7, and the other is connected to the ground through a ninth resistor R9. The second output terminal and the seventh resistor R7 are connected to a processor (6) through an eighth resistor R8.

4. The sensor circuit used in a range hood according to claim 3, characterized in that: The differential amplifier module (3) further comprises a voltage follower U3A connected between the zero-adjusting infrared receiving module (1) and the secondary differential amplifier circuit, and a voltage follower U3B connected between the detecting infrared receiving module (2) and the secondary differential amplifier circuit; the voltage follower U3A is connected to the differential amplifier module (3) via a fourth resistor R4, and the voltage follower U3B is connected to the differential amplifier module (3) via a second resistor R2.

5. The sensor circuit used in a range hood according to claim 1, characterized in that: The differential amplifier module (3) comprises a secondary conventional amplifier circuit, a differential amplifier circuit, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and an eighth resistor R8; The first negative input terminal of the secondary conventional amplifier circuit is connected to the second negative input terminal via a resistor RG, the first positive input terminal is connected to the detection infrared receiving module (2) via a second resistor R2, the first output terminal is connected to the positive input terminal of the differential amplifier circuit via a fourth resistor R4, and a third resistor R3 is further connected between the first output terminal and the first negative input terminal; The second positive input terminal of the secondary conventional amplifier circuit is connected to the zero-adjusting infrared receiving module (1) via a fourth resistor R4, the second output terminal is connected to the negative input terminal of the differential amplifier circuit via a sixth resistor R6, and the second negative input terminal and the second output terminal are connected to a fifth resistor R5; The positive input terminal of the differential amplifier circuit is grounded via an eighth resistor R8, the negative input terminal is connected to the processor (6) via a seventh resistor R7, and the output terminal is connected to the processor (6).

6. The sensor circuit used in a range hood according to claim 1, characterized in that: The temperature acquisition module (5) comprises a thermistor RZ and a tenth resistor R10; One end of the thermistor RZ is connected to a power source, and the other end is grounded via a tenth resistor R10. A processor (6) is connected between the thermistor RZ and the tenth resistor R10.

7. The sensor circuit used in a range hood according to claim 1, characterized in that: The processor (6) comprises a chip U1, a burning module and a serial communication module. The burning module and the serial communication module are both connected to the chip U1. The ninth terminal of the chip U1 is connected to a power supply, the tenth terminal is grounded, the second terminal is connected to a temperature acquisition module (5), and the 20th terminal is connected to a differential amplifier module (3).

8. The sensor circuit used in a range hood according to claim 7, characterized in that: The serial communication module includes a serial communication module CN2, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, and a second capacitor C2; The first terminal of the serial communication module CN2 is connected to a power supply, the second terminal outputs an RX signal through a thirteenth resistor R13, the third terminal outputs a TX signal through a fourteenth resistor R14, the fourth terminal is grounded, a first capacitor C1 is connected in parallel between the second terminal and the fourth terminal, and a second capacitor C2 is connected in parallel between the third terminal and the fourth terminal.

9. A range hood, characterized in that: The invention comprises a range hood body (7), a range hood turbine (8) and a sensor circuit applied to the range hood as described in claims 1 to 8, wherein the range hood turbine (8) is arranged on the range hood body (7), and a detection infrared receiving module (2) in the sensor circuit is arranged at the air inlet at the edge of the range hood turbine (8).

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