High-low voltage protection circuit of ultrasonic liquid level sensor

Abstract

The utility model discloses a high-low voltage protection circuit of an ultrasonic liquid level sensor, which comprises a main control chip electrically connected with a power supply, a voltage comparison unit, a high-low voltage protection circuit and a voltage output unit. The main control chip comprises a chip U5, the high and low voltage protection circuit comprises a diode D3, a negative electrode of the diode D3 is electrically connected with a pin 1 of a fuse F1, and a pin 2 of the fuse F1 is electrically connected with a negative electrode of a suppression diode TVS3, one end of a capacitor C19 and one end of a resistor R18. According to the ultrasonic liquid level sensor, input voltage is compared, when the voltage is high or low, voltage regulation operation is carried out in time through the high-low voltage protection circuit, the purpose of voltage stabilization is achieved, the circuit in the ultrasonic liquid level sensor can rapidly return to a normal working state, and therefore the ultrasonic liquid level sensor can work normally and stably, and the service life of the ultrasonic liquid level sensor is prolonged. And use requirements are met.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrasonic liquid level sensors, in particular to a high and low voltage protection circuit for an ultrasonic liquid level sensor. Background Technique

[0002] The ultrasonic liquid level sensor can be directly installed outside the liquid container, such as at the bottom, and there is no need to drill holes or perform other operations at the installation position of the liquid container. Therefore, it is more and more widely used. When the ultrasonic liquid level sensor works, it requires a safe and stable power supply voltage. However, due to the instant power-on or other situations, sometimes the power supply voltage will suddenly increase or decrease. If the corresponding large voltage directly acts on some circuits and chips of the ultrasonic liquid level sensor, it will cause damage to these circuits and chips. A smaller voltage will affect the normal operation of the ultrasonic liquid level sensor and cannot meet the usage requirements. Therefore, we propose a high and low voltage protection circuit for an ultrasonic liquid level sensor. Content of the Utility Model

[0003] The purpose of the utility model is to solve the shortcomings existing in the prior art, and to propose a high and low voltage protection circuit for an ultrasonic liquid level sensor.

[0004] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0005] A high and low voltage protection circuit for an ultrasonic liquid level sensor, including a main control chip, the main control chip is electrically connected to a power supply, a voltage comparison unit, a high and low voltage protection circuit and a voltage output unit;

[0006] The main control chip includes chip U5. The high and low voltage protection circuit includes diode D3. The negative electrode of diode D3 is electrically connected to pin 1 of fuse F1. Pin 2 of fuse F1 is electrically connected to the negative electrode of suppression diode TVS3, one end of capacitor C19, and one end of resistor R18. Pin 2 of fuse F1 is also electrically connected to pin 7 of chip U5. The positive electrode of suppression diode TVS3 and the other end of capacitor C19 are both grounded. Pin 6 and pin 5 of chip U5 are electrically connected to the same resistor R17. Pin 8 of chip U5 is electrically connected to one end of capacitor C21. The other end of capacitor C21 is electrically connected to pin 1 of chip U5. Pin 1 of chip U5 is also electrically connected to the negative electrode of diode D4 and one end of coil L2. The other end of coil L2 is electrically connected to one end of capacitor C22. The positive electrode of diode D4 and the other end of capacitor C22 are both grounded. Pin 4 of chip U5 is electrically connected to one end of resistor R21 and one end of resistor R22. The other end of resistor R22 is electrically connected to one end of capacitor C22. The other end of resistor R21 is electrically connected to one end of resistor R19. The other end of resistor R19 is electrically connected to one end of capacitor C20. Pin 2 of chip U5 is electrically connected to one end of resistor R20. The other end of resistor R20 is grounded.

[0007] Preferably, the voltage comparison unit includes comparator U1. Pin 1 of comparator U1 is electrically connected to one end of resistor R3. The other end of resistor R3 is electrically connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R2 is grounded. Pin 2 of comparator U1 is electrically connected to one end of resistor R4. The other end of resistor R4 is electrically connected to pin 3 of chip U5. Pin 4 of comparator U1 is grounded. Pin 3 of comparator U1 is electrically connected to one end of resistor R5. The other end of resistor R5 and pin 5 of comparator U1 are both electrically connected to high frequency VCC. Pin 3 of comparator U1 is also electrically connected to the other end of capacitor C20.

[0008] Preferably, the model of chip U5 is MP4560DN.

[0009] Preferably, the parameter of diode D4 is SS24, and the parameter of diode D3 is SS2 / 34.

[0010] Preferably, one end of diode D3 is the power input terminal, and the input is direct current DC.

[0011] Preferably, the fuse F1 is used to protect the circuit and prevent the circuit from being burned out due to excessive current. The model of fuse F1 can be 72XF020.

[0012] Preferably, the suppression diode TVS3 is a transient voltage suppression diode. The transient suppression diode has the characteristics of fast response speed, large transient power, low leakage current, and small breakdown voltage deviation.

[0013] Compared with the existing technology, the beneficial effects of the present utility model are as follows:

[0014] By comparing the input voltage and adjusting the voltage in a timely manner through the high and low voltage protection circuit when the voltage is too high or too low, the present utility model achieves the purpose of voltage stabilization, enabling the circuit in the ultrasonic liquid level sensor to quickly return to the normal working state, so that the ultrasonic liquid level sensor can work normally and stably, meeting the usage requirements. Description of the Drawings

[0015] Figure 1 It is a connection block diagram of the high and low voltage protection circuit of an ultrasonic liquid level sensor proposed by the present utility model;

[0016] Figure 2 It is a connection circuit diagram of the high and low voltage protection circuit and chip U5 of the high and low voltage protection circuit of an ultrasonic liquid level sensor proposed by the present utility model;

[0017] Figure 3 It is a circuit diagram of the voltage comparison unit of the high and low voltage protection circuit of an ultrasonic liquid level sensor proposed by the present utility model. Specific Embodiments

[0018] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments.

[0019] Referring to Figures 1 - 3 , a high and low voltage protection circuit of an ultrasonic liquid level sensor includes a main control chip, and the main control chip is electrically connected to a power supply, a voltage comparison unit, a high and low voltage protection circuit, and a voltage output unit;

[0020] The main control chip includes chip U5, and the model of chip U5 is MP4560DN;

[0021] The high and low voltage protection circuit includes diode D3, and the parameter of diode D3 is SS2 / 34. One end of diode D3 is the power input terminal, and the input is direct current DC. The negative electrode of diode D3 is electrically connected to pin 1 of fuse F1, and fuse F1 is used to protect the circuit and prevent the circuit from burning due to excessive current. The model of fuse F1 can be 72XF020;

[0022] Pin 2 of fuse F1 is electrically connected to the negative electrode of transient voltage suppression diode TVS3, one end of capacitor C19, and one end of resistor R18. Pin 2 of fuse F1 is also electrically connected to pin 7 of chip U5. The positive electrode of transient voltage suppression diode TVS3 and the other end of capacitor C19 are both grounded. Among them, transient voltage suppression diode TVS3 is a transient voltage suppression diode, which has the characteristics of fast response speed, large transient power, low leakage current, and small breakdown voltage deviation. Pin 6 and pin 5 of chip U5 are electrically connected to the same resistor R17. Pin 8 of chip U5 is electrically connected to one end of capacitor C21. The other end of capacitor C21 is electrically connected to pin 1 of chip U5. Pin 1 of chip U5 is also electrically connected to the negative electrode of diode D4 and one end of coil L2. Among them, the parameter of diode D4 is SS24. The other end of coil L2 is electrically connected to one end of capacitor C22. The positive electrode of diode D4 and the other end of capacitor C22 are both grounded. Pin 4 of chip U5 is electrically connected to one end of resistor R21 and one end of resistor R22. The other end of resistor R22 is electrically connected to one end of capacitor C22. The other end of resistor R21 is electrically connected to one end of resistor R19. The other end of resistor R19 is electrically connected to one end of capacitor C20. Pin 2 of chip U5 is electrically connected to one end of resistor R20. The other end of resistor R20 is grounded;

[0023] The voltage comparison unit includes comparator U1. Pin 1 of comparator U1 is electrically connected to one end of resistor R3. The other end of resistor R3 is electrically connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R2 is grounded. Pin 2 of comparator U1 is electrically connected to one end of resistor R4. The other end of resistor R4 is electrically connected to pin 3 of chip U5. Pin 4 of comparator U1 is grounded. Pin 3 of comparator U1 is electrically connected to one end of resistor R5. The other end of resistor R5 and pin 5 of comparator U1 are both electrically connected to high-level VCC. Pin 3 of comparator U1 is also electrically connected to the other end of capacitor C20;

[0024] The utility model compares the input voltage, and when the voltage is too high or too low, the voltage regulation operation is carried out in time through the high and low voltage protection circuit to achieve the purpose of voltage stabilization, so that the circuit in the ultrasonic liquid level sensor can quickly return to the normal working state, so that the ultrasonic liquid level sensor can work normally and stably, meeting the use requirements.

[0025] Working principle: When in use, the power supply is input into the main control chip and then given to the voltage comparison unit. The voltage comparison unit uses the comparator U1 and multiple resistors to cooperate to compare and detect the input voltage. If it detects that the voltage is too high or too low, then through the cooperation of multiple diodes and capacitors in the high and low voltage protection circuit, the voltage is adjusted so that the voltage input to the main control chip again is a stable voltage. The stable voltage is output through the voltage output unit, enabling the entire circuit to output voltage normally and work properly.

[0026] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A high and low voltage protection circuit for an ultrasonic liquid level sensor, including a main control chip, characterized in that, The main control chip is electrically connected to a power supply, a voltage comparison unit, a high and low voltage protection circuit, and a voltage output unit; The main control chip includes chip U5. The high and low voltage protection circuit includes diode D3. The negative electrode of diode D3 is electrically connected to pin 1 of fuse F1. Pin 2 of fuse F1 is electrically connected to the negative electrode of suppression diode TVS3, one end of capacitor C19, and one end of resistor R18. Pin 2 of fuse F1 is also electrically connected to pin 7 of chip U5. The positive electrode of suppression diode TVS3 and the other end of capacitor C19 are both grounded. The same resistor R17 is electrically connected between pin 6 and pin 5 of chip U5. One end of capacitor C21 is electrically connected to pin 8 of chip U5, and the other end of capacitor C21 is electrically connected to pin 1 of chip U5. Pin 1 of chip U5 is also electrically connected to the negative electrode of diode D4 and one end of coil L2. The other end of coil L2 is electrically connected to one end of capacitor C22. The positive electrode of diode D4 and the other end of capacitor C22 are both grounded. Pin 4 of chip U5 is electrically connected to one end of resistor R21 and one end of resistor R22. The other end of resistor R22 is electrically connected to one end of capacitor C22. The other end of resistor R21 is electrically connected to one end of resistor R19. The other end of resistor R19 is electrically connected to one end of capacitor C20. Pin 2 of chip U5 is electrically connected to one end of resistor R20, and the other end of resistor R20 is grounded.

2. The high and low voltage protection circuit of an ultrasonic liquid level sensor according to claim 1, wherein The voltage comparison unit includes comparator U1. One end of resistor R3 is electrically connected to pin 1 of comparator U1. The other end of resistor R3 is electrically connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R2 is grounded. One end of resistor R4 is electrically connected to pin 2 of comparator U1. The other end of resistor R4 is electrically connected to pin 3 of chip U5. Pin 4 of comparator U1 is grounded. One end of resistor R5 is electrically connected to pin 3 of comparator U1. The other end of resistor R5 and pin 5 of comparator U1 are both electrically connected to high frequency VCC. Pin 3 of comparator U1 is also electrically connected to the other end of capacitor C20.

3. The high and low voltage protection circuit of an ultrasonic liquid level sensor according to claim 1, characterized in that, The model of chip U5 is MP4560DN.

4. The high and low voltage protection circuit of an ultrasonic liquid level sensor according to claim 1, characterized in that, The parameter of diode D4 is SS24, and the parameter of diode D3 is SS2 / 34.

5. The high and low voltage protection circuit of an ultrasonic liquid level sensor according to claim 1, characterized in that, One end of diode D3 is the power input terminal, and the input is direct current DC.

6. The high and low voltage protection circuit of an ultrasonic liquid level sensor according to claim 1, characterized in that, The fuse F1 is used to protect the circuit and prevent the circuit from burning out due to excessive current. The model of fuse F1 can be 72XF020.

7. The high and low voltage protection circuit of an ultrasonic liquid level sensor according to claim 1, characterized in that The suppression diode TVS3 is a transient voltage suppression diode.

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