Water level detection circuit and water level detection device

Abstract

The utility model discloses a water level detection circuit, and disclose having water level detection equipment of water level detection circuit, wherein water level detection circuit includes: control chip, water level equivalent branch, first input, second input, power connection end, first triode, amplifier and first output, the collector of first triode is connected with power connection end second input the first end of amplifier and the first end of water level equivalent branch respectively, control chip passes through first output and the third end of amplifier is connected, first input is connected with the base of first triode, the emitter of first triode is grounded, the second end of water level equivalent branch is grounded, wherein, water level equivalent branch includes first capacitor and first resistance that parallel each other. The utility model can be compatible with ac detection and dc detection, and effectively improve detection accuracy.

Description

Technical Field

[0001] This utility model relates to the field of water level detection technology, and in particular to a water level detection circuit and a water level detection device. Background Technology

[0002] Many instruments and equipment require frequent water replenishment, such as humidity chambers and salt spray chambers. However, users are often unaware of the water level in these instruments, necessitating frequent monitoring. Current technologies primarily employ either a single DC or single AC method for detection. Single DC methods suffer from probe corrosion, while single AC methods exhibit weak interference resistance, are unsuitable for certain applications, and are prone to false alarms. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a water level detection circuit that is compatible with both AC and DC detection, effectively improving detection accuracy.

[0004] This utility model also proposes a water level detection device having the above-mentioned water level detection circuit.

[0005] A water level detection circuit according to a first aspect of the present invention includes: a control chip, a water level equivalent branch, a first input terminal, a second input terminal, a power supply connection terminal, a first transistor, an amplifier, and a first output terminal. The collector of the first transistor is connected to the power supply connection terminal, the second input terminal, the first terminal of the amplifier, and the first terminal of the water level equivalent branch. The control chip is connected to the third terminal of the amplifier through the first output terminal. The first input terminal is connected to the base of the first transistor. The emitter of the first transistor is grounded. The second terminal of the water level equivalent branch is grounded. The water level equivalent branch includes a first capacitor and a first resistor connected in parallel.

[0006] The water level detection circuit according to this utility model embodiment has at least the following beneficial effects: In AC detection mode, when the first input terminal outputs a square wave signal, the first output terminal will follow the voltage value of the water level equivalent branch and eliminate the negative voltage, leaving only the positive voltage. The control chip can effectively identify states such as touching the liquid surface, leaving the liquid surface, grounding, and a person touching the water tank casing by obtaining the voltage change of the sampling water level equivalent branch through the first output port. In DC detection mode, the second input terminal outputs a high level, and the control chip can effectively identify states such as touching the liquid surface, leaving the liquid surface, grounding, and a person touching the water tank casing by obtaining the voltage change of the sampling water level equivalent branch through the first output port. Through AC / DC compatibility, it can be used in different application scenarios. At the same time, the use of an operational amplifier to improve the input impedance of the sampling circuit enhances the anti-interference capability.

[0007] According to some embodiments of the present invention, the water level detection circuit further includes a second resistor, and the first input terminal is connected to the base of the first transistor through the second resistor.

[0008] According to some embodiments of the present invention, the water level detection circuit further includes a third resistor, the first end of which is connected between the second resistor and the base of the first transistor, and the second end of which is grounded.

[0009] According to some embodiments of the present invention, the water level detection circuit further includes a fourth resistor, and the power supply connection terminal is connected to the collector of the first transistor through the fourth resistor.

[0010] According to some embodiments of the present invention, the water level detection circuit further includes a second capacitor and a fifth resistor. The first end of the second capacitor is connected between the collector of the first transistor and the fourth resistor, and the second end of the second capacitor is connected to the first end of the amplifier.

[0011] According to some embodiments of the present invention, the water level detection circuit further includes a sixth resistor, the first end of which is connected to the second input terminal, and the second end of which is connected to the second end of the fifth resistor, the first end of the water level equivalent branch, and the first end of the amplifier.

[0012] According to some embodiments of the present invention, the water level detection circuit further includes a seventh resistor, the first end of which is connected to the second end of the sixth resistor, the second end of the fifth resistor and the first end of the water level equivalent branch, and the second end of the seventh resistor is connected to the first end of the amplifier.

[0013] According to some embodiments of the present invention, the water level detection circuit further includes an eighth resistor, the third terminal of the amplifier is connected to the first output terminal through the eighth resistor, and the second terminal of the amplifier is connected between the third terminal of the amplifier and the eighth resistor.

[0014] According to some embodiments of the present invention, the water level detection circuit further includes a third capacitor, the first end of which is connected between the eighth resistor and the first output terminal, and the second end of which is grounded.

[0015] The water level detection device according to a second aspect embodiment of the present invention includes the water level detection circuit described in the above embodiment. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the water level detection circuit provided in an embodiment of the present invention. Detailed Implementation

[0017] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0018] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" and "second" are mentioned, they are only used to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0020] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0021] Reference Figure 1 , Figure 1 This is a schematic diagram of the water level detection circuit provided in an embodiment of the present invention.

[0022] It is understood that the water level detection circuit includes: a control chip, a water level equivalent branch 100, a first input terminal Water_PWM, a second input terminal Water_10, a power supply connection terminal 5V, a first transistor Q1, an amplifier U2B, a first output terminal Water_AD, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a second capacitor C2, and a third capacitor C3. The first input terminal Water_PWM is connected to the base of the first transistor Q1 through the second resistor R2. The first end of the third resistor R3 is connected between the second resistor R2 and the base of the first transistor Q1, and the second end of the third resistor R3 is grounded. The emitter of the first transistor Q1 is grounded. The power supply connection terminal 5V is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is connected to the collector of the first transistor Q1 and the first end of the second capacitor C2. The second terminal of capacitor C2 is connected to the first terminal of resistor R5. The second terminal of resistor R5 is connected to the second terminal of resistor R6, the first terminal of resistor R7, and the first terminal of water level equivalent branch 100. The second terminal of resistor R7 is connected to the first terminal of amplifier U2B. The first terminal of resistor R6 is connected to the second input terminal Water_10. The first terminal of resistor R8 is connected to the second and third terminals of amplifier U2B. The second terminal of resistor R8 is connected to the first output terminal Water_AD. The first terminal of capacitor C3 is connected between resistor R8 and the first output terminal Water_AD. The second terminal of capacitor C3 is grounded. The control chip is connected to resistor R8 through the first output terminal Water_AD. The second terminal of water level equivalent branch 100 is grounded. Water level equivalent branch 100 includes capacitor C1 and resistor R1 connected in parallel.

[0023] It should be noted that in AC detection mode, when the first input terminal Water_PWM outputs a square wave signal, the first output terminal Water_AD will follow the voltage value of the water level equivalent branch 100, eliminating negative voltage and leaving only positive voltage. The control chip can effectively identify states such as touching the liquid surface, leaving the liquid surface, grounding, and touching the water tank casing by hand by obtaining the voltage change of the water level equivalent branch 100 through the first output terminal Water_AD. In DC detection mode, the second input terminal Water_10 outputs a high level, and the sixth resistor R6 forms a voltage divider circuit with the water level equivalent branch 100. The control chip can effectively identify states such as touching the liquid surface, leaving the liquid surface, grounding, and touching the water tank casing by hand by obtaining the voltage change of the water level equivalent branch 100 through the first output terminal Water_AD. Through AC / DC compatibility, it can be used in different application scenarios. At the same time, the use of operational amplifier U2B improves the input impedance of the sampling circuit and enhances the anti-interference capability.

[0024] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A water level detection circuit, characterized in that, include: The system comprises a control chip, a water level equivalent branch, a first input terminal, a second input terminal, a power supply connection terminal, a first transistor, an amplifier, and a first output terminal. The collector of the first transistor is connected to the power supply connection terminal, the second input terminal, the first terminal of the amplifier, and the first terminal of the water level equivalent branch. The control chip is connected to the third terminal of the amplifier through the first output terminal. The first input terminal is connected to the base of the first transistor. The emitter of the first transistor is grounded. The second terminal of the water level equivalent branch is grounded. The water level equivalent branch includes a first capacitor and a first resistor connected in parallel.

2. The water level detection circuit according to claim 1, characterized in that, The water level detection circuit also includes a second resistor, and the first input terminal is connected to the base of the first transistor through the second resistor.

3. The water level detection circuit according to claim 2, characterized in that, The water level detection circuit also includes a third resistor, the first end of which is connected between the second resistor and the base of the first transistor, and the second end of which is grounded.

4. The water level detection circuit according to claim 1, characterized in that, The water level detection circuit also includes a fourth resistor, and the power supply connection terminal is connected to the collector of the first transistor through the fourth resistor.

5. The water level detection circuit according to claim 4, characterized in that, The water level detection circuit further includes a second capacitor and a fifth resistor. The first end of the second capacitor is connected between the collector of the first transistor and the fourth resistor, and the second end of the second capacitor is connected to the first end of the amplifier.

6. The water level detection circuit according to claim 5, characterized in that, The water level detection circuit further includes a sixth resistor, the first end of which is connected to the second input terminal, and the second end of which is connected to the second end of the fifth resistor, the first end of the water level equivalent branch, and the first end of the amplifier.

7. The water level detection circuit according to claim 6, characterized in that, The water level detection circuit further includes a seventh resistor, the first end of which is connected to the second end of the sixth resistor, the second end of the fifth resistor, and the first end of the water level equivalent branch, and the second end of the seventh resistor is connected to the first end of the amplifier.

8. The water level detection circuit according to claim 1, characterized in that, The water level detection circuit further includes an eighth resistor. The third terminal of the amplifier is connected to the first output terminal through the eighth resistor, and the second terminal of the amplifier is connected between the third terminal of the amplifier and the eighth resistor.

9. The water level detection circuit according to claim 8, characterized in that, The water level detection circuit also includes a third capacitor, the first end of which is connected between the eighth resistor and the first output terminal, and the second end of which is grounded.

10. A water level detection device, characterized in that, Includes the water level detection circuit as described in any one of claims 1 to 9.

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