Resistance value switching circuit

Abstract

The utility model discloses a resistance value switching circuit, which comprises a resistance switching unit comprising a plurality of parallel resistance channels and a chip U4, and the chip U4 is respectively connected with a controller in an optical fiber temperature measurement circuit and the plurality of parallel resistance channels and is used for outputting different resistance values; the power supply unit is connected with the resistance switching unit and used for supplying power to the resistance switching unit, the effect of outputting different resistance values according to instructions can be achieved, and therefore compatibility between optical fiber temperature measurement and a thermistor interface is achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to temperature measurement technical field, concretely relates to a resistance value switching circuit. BACKGROUND

[0002] The thermistor is also a thermistor temperature sensor, or called NTC temperature sensor (Negative Temperature Coefficient Sensor), and the resistance value thereof decreases with the temperature rise, and is widely used in various temperature measuring equipment, but the thermistor temperature sensor is susceptible to electromagnetic interference and temperature drift and other factors when transmitting in a high-temperature and high-voltage environment, and the optical fiber temperature measurement in the prior art is not susceptible to interference, but it cannot be directly read by the equipment with a thermistor interface, and the current optical fiber temperature measurement scheme needs to replace the entire equipment, causing unnecessary resource waste.

[0003] Therefore, how to output different resistance values in optical fiber temperature measurement to represent different temperatures, so as to realize the compatibility between optical fiber temperature measurement and thermistor interface, and at the same time avoid the interference of temperature data in a high-temperature and high-voltage environment, is a technical problem to be solved by the person skilled in the art. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at solving the technical problem that different resistance values cannot be output in the prior art optical fiber temperature measurement, and provides a resistance value switching circuit, which comprises:

[0005] The resistance switching unit comprises a plurality of parallel resistance channels and a chip U4, the chip U4 is connected with the controller in the optical fiber temperature measurement circuit and the plurality of parallel resistance channels respectively, and is used for outputting different resistance values;

[0006] The power supply unit is connected with the resistance switching unit and is used for supplying power for the resistance switching unit.

[0007] Further, the parallel resistance channels comprise at least S1 channel to S8 channel, and specifically comprise:

[0008] The S1 channel includes resistors R2, R3, R4 and R5, the S2 channel includes resistors R6, R7, R8 and R9, the S3 channel includes resistors R11, R12, R13 and R14, the S4 channel includes resistors R15, R16, R17 and R18, the S5 channel includes resistors R19, R20, R21 and R23, the S6 channel includes resistors R24, R25, R27 and R28, the S7 channel includes resistors R29, R30, R31 and R32, the S8 channel includes resistors R35, R36, R37 and R38, one end of the resistor R2, one end of the resistor R4, one end of the resistor R6, one end of the resistor R8, one end of the resistor R11, one end of the resistor R13, one end of the resistor R15, one end of the resistor R17, one end of the resistor R19, one end of the resistor R22, one end of the resistor R24, one end of the resistor R27, one end of the resistor R29, one end of the resistor R31, one end of the resistor R35 and one end of the resistor R37 are connected with the D-pin in the controller, the other end of the resistor R3, the other end of the resistor R5, the other end of the resistor R7, the other end of the resistor R9, the other end of the resistor R12, the other end of the resistor R14, the other end of the resistor R16, the other end of the resistor R18, the other end of the resistor R20, the other end of the resistor R23, the other end of the resistor R25, the other end of the resistor R28, the other end of the resistor R30, the other end of the resistor R32, the other end of the resistor R36 and the other end of the resistor R38 are connected with the chip U4, the other end of the resistor R2 is connected with the other end of the resistor R4, one end of the resistor R3 and one end of the resistor R5 at the same time, the other end of the resistor R6 is connected with one end of the resistor R7, the other end of the resistor R8 and one end of the resistor R9 at the same time, the other end of the resistor R11 is connected with one end of the resistor R12, the other end of the resistor R13 and one end of the resistor R14 at the same time, the other end of the resistor R15 is connected with one end of the resistor R16, the other end of the resistor R17 and one end of the resistor R18 at the same time, the other end of the resistor R19 is connected with one end of the resistor R20, the other end of the resistor R22 and one end of the resistor R23 at the same time, the other end of the resistor R24 is connected with one end of the resistor R25, the other end of the resistor R27 and one end of the resistor R28 at the same time, the other end of the resistor R29 is connected with one end of the resistor R30, the other end of the resistor R31 and one end of the resistor R32 at the same time, the other end of the resistor R35 is connected with one end of the resistor R36, the other end of the resistor R37 and one end of the resistor R38 at the same time.

[0009] Further, the pin 4 of the chip U4 is connected with the other end of the resistor R3 and the other end of the resistor R5 respectively, the pin 5 of the chip U4 is connected with the other end of the resistor R7 and the other end of the resistor R9 respectively, the pin 6 of the chip U4 is connected with the other end of the resistor R12 and the other end of the resistor R14 respectively, the pin 7 of the chip U4 is connected with the other end of the resistor R16 and the other end of the resistor R18 respectively, the pin 12 of the chip U4 is connected with the other end of the resistor R20 and the other end of the resistor R23 respectively, the pin 11 of the chip U4 is connected with the other end of the resistor R25 and the other end of the resistor R28 respectively, the pin 10 of the chip U4 is connected with the other end of the resistor R30 and the other end of the resistor R32 respectively, the pin 9 of the chip U4 is connected with the other end of the resistor R36 and the other end of the resistor R38 respectively, the pin 3 of the chip U4 is grounded, the pin 13 of the chip U4 is connected with the other end of the capacitor C26 and the 3.3V power supply respectively, the pin 14 of the chip U4 is grounded and is also connected with one end of the capacitor C26, the pin 1, the pin 2, the pin 15 and the pin 16 of the chip U4 are connected with the controller in the fiber temperature measurement circuit.

[0010] Further, the resistance values of the channels S1 to S8 are not the same.

[0011] Further, the power supply unit specifically comprises a 24V to 5V power supply circuit and a 5V to 3.3V power supply circuit, wherein the 24V to 5V power supply circuit specifically comprises:

[0012] The anode of the diode D1 and one end of the bidirectional voltage stabilizing diode D2 are connected with the 24V power supply, the other end of the bidirectional voltage stabilizing diode D2 is grounded, the cathode of the diode D1 is connected with the 24V power supply, one end of the capacitor C9, one end of the capacitor C10, one end of the capacitor C11, one end of the capacitor C12, one end of the capacitor C13 and one end of the capacitor C14 respectively, the cathode of the diode D1 is also connected with the pin 2 of the chip U1, the pin 1 of the chip U1 is grounded, the pin 6 of the chip U1 outputs 5V electricity, the pin 6 of the chip U1 is also connected with one end of the capacitor C1, one end of the capacitor C2, one end of the capacitor C3, one end of the capacitor C4 and one end of the bidirectional voltage stabilizing diode D3 respectively, the pin 7 of the chip U1, the other end of the capacitor C1, the other end of the capacitor C2, the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the bidirectional voltage stabilizing diode D3 are all grounded.

[0013] Further, the 5V to 3.3V power supply circuit specifically comprises:

[0014] The pin 1 of the chip U2, the pin 3 of the chip U2, one end of the capacitor C5 and one end of the capacitor C6 are electrically connected with 5V, the pin 2 of the chip U2 is grounded, the other end of the capacitor C5 and the other end of the capacitor C6 are grounded, the pin 5 of the chip U2 outputs 3.3V electricity, the pin 5 of the chip U2 is connected with one end of the capacitor C7 and one end of the capacitor C8 respectively, and the other end of the capacitor C7 and the other end of the capacitor C8 are grounded.

[0015] Compared with the prior art, the utility model has the advantages that:

[0016] The resistance value switching circuit provided by the utility model has the advantages that compared with the prior art, the circuit comprises a resistance switching unit, a plurality of parallel resistance channels and a chip U4, the chip U4 is connected with a controller in an optical fiber temperature measuring circuit and the plurality of parallel resistance channels respectively and is used for outputting different resistance values, a power supply unit is connected with the resistance switching unit and is used for supplying power for the resistance switching unit, the effect of outputting different resistance values according to instructions can be realized, and the compatibility between the optical fiber temperature measurement and the thermistor interface can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, and the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor on the premise of the drawings.

[0018] Figure 1 Fig. 1 shows the overall structure schematic diagram of the resistance value switching circuit provided by the embodiments of the present application;

[0019] Figure 2 Fig. 2 shows the structure schematic diagram of the parallel resistance channel provided by the embodiments of the present application;

[0020] Figure 3 Fig. 3 shows the connection structure schematic diagram of the chip U4 in the embodiments of the present application;

[0021] Figure 4 Fig. 4 shows the structure schematic diagram of the 24V to 5V power supply circuit in the embodiments of the present application;

[0022] Figure 5 Fig. 5 shows the structure schematic diagram of the 5V to 3.3V power supply circuit in the embodiments of the present application. DETAILED DESCRIPTION

[0023] In order for those skilled in the technical field to better understand the technical solutions in the specification, the technical solutions in the specification will be clearly and completely described in the specification combined with the drawings in the specification. Obviously, the described embodiments are only part of the embodiments of the specification, not all. Based on the embodiments in the specification, all other embodiments obtained by those of ordinary skill in the art without creative labor should be within the scope of protection of the specification.

[0024] As shown in Figure 1 The overall structure of the resistance value switching circuit provided by the embodiment of the specification is shown in the figure. Although the specification provides the structure shown in the following embodiments or figures, more or less structures can be included in the structure based on convention or without creative labor, and these structures are not limited to the structures shown in the embodiments or figures of the specification. The structure described in the actual device or terminal product application can be sequentially executed or executed in parallel according to the embodiment or module structure.

[0025] The resistance value switching circuit provided in the embodiment of the specification can be applied in the optical fiber temperature measurement circuit in high temperature and high voltage places, and the circuit includes:

[0026] The resistance switching unit includes a plurality of parallel resistance channels and a chip U4, the chip U4 is connected with the controller in the optical fiber temperature measurement circuit and the plurality of parallel resistance channels respectively, and is used for outputting different resistance values;

[0027] The power supply unit is connected with the resistance switching unit, and is used for supplying power for the resistance switching unit.

[0028] In the embodiment of the present application, the parallel resistance channel includes at least S1 channel to S8 channel, as shown in Figure 2 The structure of the parallel resistance channel is shown in the figure, specifically:

[0029] The S1 channel includes resistors R2, R3, R4 and R5, the S2 channel includes resistors R6, R7, R8 and R9, the S3 channel includes resistors R11, R12, R13 and R14, the S4 channel includes resistors R15, R16, R17 and R18, the S5 channel includes resistors R19, R20, R21 and R23, the S6 channel includes resistors R24, R25, R27 and R28, the S7 channel includes resistors R29, R30, R31 and R32, the S8 channel includes resistors R35, R36, R37 and R38, one end of the resistor R2, one end of the resistor R4, one end of the resistor R6, one end of the resistor R8, one end of the resistor R11, one end of the resistor R13, one end of the resistor R15, one end of the resistor R17, one end of the resistor R19, one end of the resistor R22, one end of the resistor R24, one end of the resistor R27, one end of the resistor R29, one end of the resistor R31, one end of the resistor R35 and one end of the resistor R37 are connected to the D-pin in the controller, the other end of the resistor R3, the other end of the resistor R5, the other end of the resistor R7, the other end of the resistor R9, the other end of the resistor R12, the other end of the resistor R14, the other end of the resistor R16, the other end of the resistor R18, the other end of the resistor R20, the other end of the resistor R23, the other end of the resistor R25, the other end of the resistor R28, the other end of the resistor R30, the other end of the resistor R32, the other end of the resistor R36 and the other end of the resistor R38 are connected to the chip U4, the other end of the resistor R2 is connected to the other end of the resistor R4, one end of the resistor R3 and one end of the resistor R5, the other end of the resistor R6 is connected to one end of the resistor R7, the other end of the resistor R8 and one end of the resistor R9, the other end of the resistor R11 is connected to one end of the resistor R12, the other end of the resistor R13 and one end of the resistor R14, the other end of the resistor R15 is connected to one end of the resistor R16, the other end of the resistor R17 and one end of the resistor R18, the other end of the resistor R19 is connected to one end of the resistor R20, the other end of the resistor R22 and one end of the resistor R23, the other end of the resistor R24 is connected to one end of the resistor R25, the other end of the resistor R27 and one end of the resistor R28, the other end of the resistor R29 is connected to one end of the resistor R30, the other end of the resistor R31 and one end of the resistor R32, the other end of the resistor R35 is connected to one end of the resistor R36, the other end of the resistor R37 and one end of the resistor R38, the resistance values of the resistors in each of the S1 to S8 channels are not the same.

[0030] Specifically, it needs to be explained that the resistance switching unit is connected with the controller in the optical fiber temperature measurement circuit or other host computer, which is used to receive the channel opening instruction, the D-pin in the controller is grounded, and because the resistance values of each channel in the S1 channel to the S8 channel are not the same, the specific value can be set by the workers in the field according to the actual situation, after receiving the instruction issued by the host computer, different resistance channels can be opened, different resistance values can be output, different temperatures can be represented, and the compatibility between the optical fiber temperature measurement and the thermistor interface is indirectly realized.

[0031] In the embodiment of the application, the pin 4 of the chip U4 is connected with the other end of the resistor R3 and the other end of the resistor R5 respectively, the pin 5 of the chip U4 is connected with the other end of the resistor R7 and the other end of the resistor R9 respectively, the pin 6 of the chip U4 is connected with the other end of the resistor R12 and the other end of the resistor R14 respectively, the pin 7 of the chip U4 is connected with the other end of the resistor R16 and the other end of the resistor R18 respectively, the pin 12 of the chip U4 is connected with the other end of the resistor R20 and the other end of the resistor R23 respectively, the pin 11 of the chip U4 is connected with the other end of the resistor R25 and the other end of the resistor R28 respectively, the pin 10 of the chip U4 is connected with the other end of the resistor R30 and the other end of the resistor R32 respectively, the pin 9 of the chip U4 is connected with the other end of the resistor R36 and the other end of the resistor R38 respectively, the pin 3 of the chip U4 is grounded, the pin 13 of the chip U4 is connected with the other end of the capacitor C26 and the 3.3V power supply respectively, the pin 14 of the chip U4 is grounded and also connected with one end of the capacitor C26, and the pin 1, the pin 2, the pin 15 and the pin 16 of the chip U4 are connected with the controller in the optical fiber temperature measurement circuit.

[0032] Specifically, the chip U4, that is, controls the opening of a plurality of parallel resistance channels, opens the specified parallel resistance channel after receiving the instruction of the host computer.

[0033] In the embodiment of the application, the power supply unit specifically includes a 24V to 5V power supply circuit and a 5V to 3.3V power supply circuit, wherein the 24V to 5V power supply circuit specifically includes:

[0034] The positive pole of diode D1 and one end of bidirectional voltage stabilizing diode D2 are connected with 24V power supply, the other end of bidirectional voltage stabilizing diode D2 is grounded, the negative pole of diode D1 is connected with 24V power supply, one end of capacitor C9, one end of capacitor C10, one end of capacitor C11, one end of capacitor C12, one end of capacitor C13 and one end of capacitor C14 respectively, the negative pole of diode D1 is also connected with pin 2 of chip U1, pin 1 of chip U1 is grounded, pin 6 of chip U1 outputs 5V electricity, pin 6 of chip U1 is also connected with one end of capacitor C1, one end of capacitor C2, one end of capacitor C3, one end of capacitor C4 and one end of bidirectional voltage stabilizing diode D3 respectively, pin 7 of chip U1, the other end of capacitor C1, the other end of capacitor C2, the other end of capacitor C3, the other end of capacitor C4 and the other end of bidirectional voltage stabilizing diode D3 are all grounded.

[0035] The 5V-to-3.3V power supply circuit specifically comprises:

[0036] Pin 1 of chip U2, pin 3 of chip U2, one end of capacitor C5 and one end of capacitor C6 are all connected with 5V electricity, pin 2 of chip U2 is grounded, the other end of capacitor C5 and the other end of capacitor C6 are both grounded, pin 5 of chip U2 outputs 3.3V electricity, pin 5 of chip U2 is also connected with one end of capacitor C7 and one end of capacitor C8 respectively, the other end of capacitor C7 and the other end of capacitor C8 are both grounded.

[0037] It should be understood that when an element is referred to as being "fixed on" or "set on" another element, it can be directly on the other element or can have an intervening element therebetween; when an element is referred to as being "connected" to another element, it can be directly connected to the other element or can have an intervening element therebetween, and in addition, "connected" as used herein can include wireless connection; the phrase "and / or" as used herein includes any one or more of the associated listed items and all combinations thereof.

[0038] It should be understood that parts of the present application can be realized in hardware, software, firmware or a combination thereof. In the above-described embodiments, a plurality of steps or methods can be realized with software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if realized in hardware, as in another embodiment, it can be realized with any one or a combination of the following technologies known in the art: discrete logic circuit with logic gate circuit for implementing logic functions on data signals, application specific integrated circuit with suitable combination logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA), etc.

[0039] Those skilled in the art of the present technology can understand that all or part of the steps carried out by the above-mentioned embodiment method can be completed by a program instructing the relevant hardware, and the program can be stored in a computer readable storage medium. When the program is executed, it includes one of the steps of the method embodiment or a combination thereof.

[0040] In addition, each functional unit in each embodiment of the present application can be integrated into one processing module, or each unit can exist physically independently, or two or more units can be integrated into one module. The integrated module can be realized in the form of hardware or in the form of a software functional module. When the integrated module is realized in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0041] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0042] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0043] Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present application.

[0044] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For those skilled in the art of the present application, without departing from the concept of the present application, a number of simple deductions or replacements can be made, which should be considered as falling within the protection scope of the present application.

Claims

1. A resistance value switching circuit, characterized by comprising: The resistance value switching circuit comprises: The resistance switching unit comprises a plurality of parallel resistance channels and a chip U4, the chip U4 is connected with a controller in the optical fiber temperature measurement circuit and the plurality of parallel resistance channels respectively, and is used for outputting different resistance values; The power supply unit is connected with the resistance switching unit and is used for supplying power for the resistance switching unit.

2. The resistance value switching circuit according to claim 1, wherein The parallel resistance channels at least comprise S1 channel to S8 channel, and specifically comprise: The S1 channel includes resistors R2, R3, R4 and R5, the S2 channel includes resistors R6, R7, R8 and R9, the S3 channel includes resistors R11, R12, R13 and R14, the S4 channel includes resistors R15, R16, R17 and R18, the S5 channel includes resistors R19, R20, R21 and R23, the S6 channel includes resistors R24, R25, R27 and R28, the S7 channel includes resistors R29, R30, R31 and R32, the S8 channel includes resistors R35, R36, R37 and R38, one end of the resistor R2, one end of the resistor R4, one end of the resistor R6, one end of the resistor R8, one end of the resistor R11, one end of the resistor R13, one end of the resistor R15, one end of the resistor R17, one end of the resistor R19, one end of the resistor R22, one end of the resistor R24, one end of the resistor R27, one end of the resistor R29, one end of the resistor R31, one end of the resistor R35 and one end of the resistor R37 are connected with the D-pin in the controller, the other end of the resistor R3, the other end of the resistor R5, the other end of the resistor R7, the other end of the resistor R9, the other end of the resistor R12, the other end of the resistor R14, the other end of the resistor R16, the other end of the resistor R18, the other end of the resistor R20, the other end of the resistor R23, the other end of the resistor R25, the other end of the resistor R28, the other end of the resistor R30, the other end of the resistor R32, the other end of the resistor R36 and the other end of the resistor R38 are connected with the chip U4, the other end of the resistor R2 is connected with the other end of the resistor R4, one end of the resistor R3 and one end of the resistor R5 at the same time, the other end of the resistor R6 is connected with one end of the resistor R7, the other end of the resistor R8 and one end of the resistor R9 at the same time, the other end of the resistor R11 is connected with one end of the resistor R12, the other end of the resistor R13 and one end of the resistor R14 at the same time, the other end of the resistor R15 is connected with one end of the resistor R16, the other end of the resistor R17 and one end of the resistor R18 at the same time, the other end of the resistor R19 is connected with one end of the resistor R20, the other end of the resistor R22 and one end of the resistor R23 at the same time, the other end of the resistor R24 is connected with one end of the resistor R25, the other end of the resistor R27 and one end of the resistor R28 at the same time, the other end of the resistor R29 is connected with one end of the resistor R30, the other end of the resistor R31 and one end of the resistor R32 at the same time, the other end of the resistor R35 is connected with one end of the resistor R36, the other end of the resistor R37 and one end of the resistor R38 at the same time.

3. The resistance value switching circuit according to claim 1, wherein The pin 4 of the chip U4 is connected with the other end of the resistor R3 and the other end of the resistor R5 respectively, the pin 5 of the chip U4 is connected with the other end of the resistor R7 and the other end of the resistor R9 respectively, the pin 6 of the chip U4 is connected with the other end of the resistor R12 and the other end of the resistor R14 respectively, the pin 7 of the chip U4 is connected with the other end of the resistor R16 and the other end of the resistor R18 respectively, the pin 12 of the chip U4 is connected with the other end of the resistor R20 and the other end of the resistor R23 respectively, the pin 11 of the chip U4 is connected with the other end of the resistor R25 and the other end of the resistor R28 respectively, the pin 10 of the chip U4 is connected with the other end of the resistor R30 and the other end of the resistor R32 respectively, the pin 9 of the chip U4 is connected with the other end of the resistor R36 and the other end of the resistor R38 respectively, the pin 3 of the chip U4 is grounded, the pin 13 of the chip U4 is connected with the other end of the capacitor C26 and the 3.3V power supply respectively, the pin 14 of the chip U4 is grounded and is also connected with one end of the capacitor C26, the pin 1, the pin 2, the pin 15 and the pin 16 of the chip U4 are connected with the controller in the fiber temperature measuring circuit.

4. The resistance value switching circuit according to claim 2, wherein The resistance values of the channels in the S1 channel to the S8 channel are not the same.

5. The resistance value switching circuit of claim 1, wherein, The power supply unit specifically comprises a 24V-to-5V power supply circuit and a 5V-to-3.3V power supply circuit, wherein the 24V-to-5V power supply circuit specifically comprises: The anode of the diode D1 and one end of the bidirectional voltage stabilizing diode D2 are connected with the 24V power supply, the other end of the bidirectional voltage stabilizing diode D2 is grounded, the cathode of the diode D1 is connected with the 24V power supply, one end of the capacitor C9, one end of the capacitor C10, one end of the capacitor C11, one end of the capacitor C12, one end of the capacitor C13 and one end of the capacitor C14 respectively, the cathode of the diode D1 is also connected with the pin 2 of the chip U1, the pin 1 of the chip U1 is grounded, the pin 6 of the chip U1 outputs 5V electricity, the pin 6 of the chip U1 is also connected with one end of the capacitor C1, one end of the capacitor C2, one end of the capacitor C3, one end of the capacitor C4 and one end of the bidirectional voltage stabilizing diode D3 respectively, the pin 7 of the chip U1, the other end of the capacitor C1, the other end of the capacitor C2, the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the bidirectional voltage stabilizing diode D3 are all grounded.

6. The resistance value switching circuit of claim 5, wherein, The 5V-to-3.3V power supply circuit specifically comprises: The pin 1 of the chip U2, the pin 3 of the chip U2, one end of the capacitor C5 and one end of the capacitor C6 are all connected with 5V electricity, the pin 2 of the chip U2 is grounded, the other end of the capacitor C5 and the other end of the capacitor C6 are both grounded, the pin 5 of the chip U2 outputs 3.3V electricity, the pin 5 of the chip U2 is also connected with one end of the capacitor C7 and one end of the capacitor C8 respectively, the other end of the capacitor C7 and the other end of the capacitor C8 are both grounded.

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