Two-stage sectional type over-temperature protection circuit

Abstract

The utility model discloses a two-stage sectional type over-temperature protection circuit which comprises a thermistor RT2 used for detecting temperature and 12V + used for providing electric energy for the thermistor RT2, a main control loop used in cooperation with the thermistor RT2 is arranged on the left side of the thermistor RT2, and a voltage feedback circuit is arranged between the main control loop and the thermistor RT2. A signal receiving end of the master control loop is electrically connected with a signal output end of the voltage feedback circuit, a signal output end of the thermistor RT2 is electrically connected with a signal input end of the voltage feedback circuit, and a power supply end of the master control loop, a power supply end of the thermistor RT2 and a power supply end of the voltage feedback circuit are respectively connected with 12V +. The electric lifting table solves the problem that in the prior art, a traditional electric lifting table is not provided with an overheating protection mechanism. The device has the advantages of simple structure, convenience in use, high safety and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of circuit protection devices in electric lifting table, more specifically, it relates to a two-stage sectional over-temperature protection circuit. BACKGROUND

[0002] With the popularity of existing electric lifting table, more and more are applied in our life and work, the function of electric lifting table is more and more developed, among which the mobile phone charging function is the most widely used;Existing driving power supply is working system, with over-temperature protection function, when electric lifting table works for a long time and triggers over-temperature protection, driving power supply stops working, at this time, mobile phone charging function also disappears, mobile phone cannot be charged, which brings inconvenience to life.

[0003] At present, a kind of electric lifting table hand controller and electric lifting table are disclosed on China patent network, publication number CN218215032U, solve the technical problem that the number of keys in prior art is more, resulting in larger overall size, the electric lifting table hand controller of the utility model, including shell and main control board arranged in the shell, the shell is equipped with roller for controlling the lifting of electric lifting table, the main control board is connected with the encoder that the rotation angle of the roller is converted into electrical signal, the main control board controls the lifting of the electric lifting table according to the electrical signal.In addition, the utility model also discloses a kind of electric lifting table, including desktop panel and above-mentioned electric lifting table hand controller, the electric lifting table hand controller is installed on the bottom surface of the desktop panel.

[0004] Although the above-mentioned patent points to a kind of electric lifting table hand controller and electric lifting table, which has the function of controlling electric lifting table by hand controller, but the protection mechanism for taking necessary measures when electric lifting table overheats is not provided in the patent, which leads to the problem that the electric lifting table is easy to be damaged after long-term use. UTILITY MODEL CONTENTS

[0005] The utility model provides a two-stage sectional over-temperature protection circuit with over-temperature protection function to overcome the problem of lack of over-temperature protection mechanism on traditional electric lifting table in prior art.

[0006] The utility model discloses a two-stage sectional type overtemperature protection circuit, including the thermistor RT2 for detecting temperature and the 12V+ for thermistor RT2 provides electric energy, the thermistor RT2 left side is equipped with with the main control loop of thermistor RT2 cooperation, the main control loop with thermistor RT2 interval is equipped with voltage feedback circuit, the signal receiving end of main control loop with voltage feedback circuit's signal output end electric connection, thermistor RT2's signal output end with voltage feedback circuit's signal input end electric connection, the power end of main control loop, thermistor RT2's power end and voltage feedback circuit's power end are connected 12V+ respectively.

[0007] As preferred, the main control loop includes a transformer auxiliary winding L1, a diode D1, a diode D2, a thermistor RT1, a resistor R1, a capacitor C1 and a main control chip U1, the 1 pin of the main control chip U1 is connected to a protection ground, the 3 pin of the main control chip U1 is electrically connected with the voltage feedback circuit, the 4 pin of the main control chip U1 is electrically connected with one end of the resistor R1, the other end of the resistor R1 is electrically connected with one end of the thermistor RT1, the other end of the thermistor RT1 is electrically connected with the negative electrode of the diode D2, the positive electrode of the diode D2 is electrically connected with the positive electrode of the diode D1 and one end of the transformer auxiliary winding L1 respectively, the other end of the transformer auxiliary winding L1 is connected to the protection ground, the negative electrode of the diode D1 is electrically connected with one end of the capacitor C1 and the 5 pin of the main control chip U1 respectively.

[0008] The model of the main control chip U1 is OB2368.

[0009] As preferred, the voltage feedback circuit comprises voltage stabilizer U3, voltage stabilizer U4, resistor R2, resistor R3, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, optocoupler U2 and MOS tube Q1, the 1 pin of the optocoupler U2 is electrically connected with the 3 pin of the main control chip U1, the 2 pin of the optocoupler U2 is connected with the protection ground, the 3 pin of the optocoupler U2 is electrically connected with one end of the resistor R2 and one end of the resistor R3 respectively, the other end of the resistor R2 is electrically connected with one end of the resistor R5, the other end of the resistor R2 outputs Vout, the 4 pin of the optocoupler U2 is electrically connected with the other end of the resistor R3 and the 1 pin of the voltage stabilizer U3 respectively, the 2 pin of the voltage stabilizer U3 is electrically connected with the other end of the resistor R5, one end of the resistor R7 and one end of the resistor R6 respectively, the 3 pin of the voltage stabilizer U3 is electrically connected with the other end of the resistor R6, the 3 pin of the voltage stabilizer U3 is connected with the signal ground, the other end of the resistor R7 is electrically connected with the 1 pin of the MOS tube Q1, the 3 pin of the MOS tube Q1 is electrically connected with one end of the resistor R8 and one end of the resistor R9 respectively, the 2 pin of the MOS tube Q1 is electrically connected with the other end of the resistor R8, the 3 pin of the voltage stabilizer U4, one end of the resistor R12 and one end of the resistor R13 respectively, the 3 pin of the voltage stabilizer U4 is connected with the signal ground, the other end of the resistor R9 is electrically connected with one end of the resistor R10 and the 1 pin of the voltage stabilizer U4 respectively, the other end of the resistor R10 is electrically connected with one end of the resistor R11, the other end of the resistor R10 is connected with 12V+, the other end of the resistor R11 is electrically connected with one end of the thermistor RT2, the other end of the thermistor RT2 is electrically connected with the 2 pin of the voltage stabilizer U4, the other end of the resistor R12 and the other end of the resistor R13 respectively.

[0010] Working principle:

[0011] When the electric lifting table continuously works, the thermistor RT2 detects that the temperature of the power device arranged in the electric lifting table rises, at this time, the resistance of the thermistor RT2 decreases, the voltage of the REF pin of the voltage stabilizer U4 slowly rises, when the voltage reaches 2.5V, the cathode voltage of the voltage stabilizer U4 decreases, the gate voltage of the MOS tube Q1 decreases, the MOS tube Q1 is in the cut-off state, at this time, the original parallel state of the resistor R6 and the resistor R7 is released, the pull-down resistance of the REF pin of the voltage stabilizer U3 becomes larger, the output voltage Vout voltage decreases, at this time, the electric lifting table triggers the first level over-temperature protection, because the output voltage decreases at this time, the voltage obtained by the motor on the electric lifting table is smaller, the motor revolution decreases, at this time, the rising or falling speed slows down, at this time, the output voltage still has voltage, the charging function of the mobile phone still exists, and the mobile phone can continue to be normally charged.

[0012] When the uncontrollable situation (such as forced lifting and lowering) occurs, if the first level over-temperature protection is triggered, the temperature of the power device in the electric lifting table continues to rise, when the temperature is high, the resistance of the thermistor RT1 decreases, at this time, the voltage of the PIN4 pin of the main control chip U1 rises, when the voltage triggers the protection threshold value of the PIN4, the main control chip U1 stops working, the auxiliary winding L1 of the transformer no longer provides power for the devices in the electric lifting table, at this time, the second level over-temperature protection is triggered, the entire power supply has no output, at this time, the motor and mobile phone charging function set in the electric lifting table stop working, and the purpose of protecting the driving power supply from being damaged is achieved.

[0013] The utility model discloses a circuit is carried around two thermistors, realizes that the lifting table can realize mobile phone charging after triggering over-temperature protection, and can also achieve the purpose of protecting the driving power supply from being damaged.

[0014] The utility model has the advantages of simple structure, convenient use and high safety. DRAWINGS

[0015] ATTACH Figure 1 It is the circuit schematic diagram of the utility model.

[0016] ATTACH Figure 2 It is the principle drawing of the main control loop of the utility model.

[0017] ATTACH Figure 3 It is the principle drawing of the voltage feedback circuit of the utility model. CONCRETE IMPLEMENTING METHOD

[0018] The technical scheme of the utility model will be further concretely explained below by examples and in combination with the drawings.

[0019] Example: according to the attached Figure 1 , the attached Figure 2 and the attached Figure 3 , the utility model is further explained, and the two-stage segmented over-temperature protection circuit of the example comprises a thermistor RT2 for detecting temperature and a 12V+ for providing power for the thermistor RT2, the left side of the thermistor RT2 is provided with a main control loop used in cooperation with the thermistor RT2, the main control loop and the thermistor RT2 are provided with a voltage feedback circuit, the signal receiving end of the main control loop and the signal output end of the voltage feedback circuit are electrically connected, the signal output end of the thermistor RT2 and the signal input end of the voltage feedback circuit are electrically connected, and the power supply end of the main control loop, the power supply end of the thermistor RT2 and the power supply end of the voltage feedback circuit are connected to the 12V+ respectively.

[0020] The main control circuit includes transformer auxiliary winding L1, diode D1, diode D2, thermistor RT1, resistor R1, capacitor C1 and main control chip U1, the 1 pin of the main control chip U1 is connected with the protection ground, the 3 pin of the main control chip U1 is electrically connected with the voltage feedback circuit, the 4 pin of the main control chip U1 is electrically connected with one end of the resistor R1, the other end of the resistor R1 is electrically connected with one end of the thermistor RT1, the other end of the thermistor RT1 is electrically connected with the negative electrode of the diode D2, the positive electrode of the diode D2 is electrically connected with the positive electrode of the diode D1 and one end of the transformer auxiliary winding L1 respectively, the other end of the transformer auxiliary winding L1 is connected with the protection ground, the negative electrode of the diode D1 is electrically connected with one end of the capacitor C1 and the 5 pin of the main control chip U1 respectively.

[0021] The voltage feedback circuit includes voltage stabilizer U3, voltage stabilizer U4, resistor R2, resistor R3, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, optocoupler U2 and MOS tube Q1, the 1 pin of the optocoupler U2 is electrically connected with the 3 pin of the main control chip U1, the 2 pin of the optocoupler U2 is connected with the protection ground, the 3 pin of the optocoupler U2 is electrically connected with one end of the resistor R2 and one end of the resistor R3 respectively, the other end of the resistor R2 is electrically connected with one end of the resistor R5, the other end of the resistor R2 outputs Vout, the 4 pin of the optocoupler U2 is electrically connected with the other end of the resistor R3 and the 1 pin of the voltage stabilizer U3 respectively, the 2 pin of the voltage stabilizer U3 is electrically connected with the other end of the resistor R5, one end of the resistor R7 and one end of the resistor R6 respectively, the 3 pin of the voltage stabilizer U3 is electrically connected with the other end of the resistor R6, the 3 pin of the voltage stabilizer U3 is connected with the signal ground, the other end of the resistor R7 is electrically connected with the 1 pin of the MOS tube Q1, the 3 pin of the MOS tube Q1 is electrically connected with one end of the resistor R8 and one end of the resistor R9 respectively, the 2 pin of the MOS tube Q1 is electrically connected with the other end of the resistor R8, the 3 pin of the voltage stabilizer U4, one end of the resistor R12 and one end of the resistor R13 respectively, the 3 pin of the voltage stabilizer U4 is connected with the signal ground, the other end of the resistor R9 is electrically connected with one end of the resistor R10 and the 1 pin of the voltage stabilizer U4 respectively, the other end of the resistor R10 is electrically connected with one end of the resistor R11, the other end of the resistor R10 is connected with 12V+, the other end of the resistor R11 is electrically connected with one end of the thermistor RT2, the other end of the thermistor RT2 is electrically connected with the 2 pin of the voltage stabilizer U4, the other end of the resistor R12 and the other end of the resistor R13 respectively.

[0022] The above merely describes specific embodiments of the present application, but the structural features of the present application are not limited thereto, and any person skilled in the art can make changes or modifications in the field of the present application, and the changes or modifications are all covered in the patent range of the present application.

Claims

1. A two-stage segmented over-temperature protection circuit, comprising a thermistor RT2 for detecting temperature and a 12V+ supplying power to the thermistor RT2, characterized in that, The thermistor RT2 has a main control circuit on its left side for use with the thermistor RT2. A voltage feedback circuit is provided between the main control circuit and the thermistor RT2. The signal receiving end of the main control circuit is electrically connected to the signal output end of the voltage feedback circuit, and the signal output end of the thermistor RT2 is electrically connected to the signal input end of the voltage feedback circuit. The power supply terminals of the main control circuit, the thermistor RT2, and the voltage feedback circuit are all connected to 12V+. The main control circuit includes a transformer auxiliary winding L1, diodes D1 and D2, thermistor RT1, resistor R1, capacitor C1, and main control chip U1. The voltage feedback circuit includes voltage regulators U3 and U4, resistors R2, R3, R5, R6, and R...

7. Resistors R8, R9, R10, R11, R12, R13, optocoupler U2, and MOSFET Q1; pin 1 of the main control chip U1 is connected to protective ground; pin 3 of the main control chip U1 is electrically connected to the voltage feedback circuit; pin 4 of the main control chip U1 is electrically connected to one end of resistor R1; the other end of resistor R1 is electrically connected to one end of thermistor RT1; the other end of thermistor RT1 is electrically connected to the negative terminal of diode D2; the positive terminal of diode D2 is electrically connected to the positive terminal of diode D1 and one end of transformer auxiliary winding L1; the other end of transformer auxiliary winding L1 is connected to protective ground; the negative terminal of diode D1 is electrically connected to one end of capacitor C1 and pin 5 of the main control chip U1.Pin 1 of the optocoupler U2 is electrically connected to pin 3 of the main control chip U1. Pin 2 of the optocoupler U2 is connected to protective ground. Pin 3 of the optocoupler U2 is electrically connected to one end of resistor R2 and one end of resistor R3. The other end of resistor R2 is electrically connected to one end of resistor R5. The other end of resistor R2 outputs Vout. Pin 4 of the optocoupler U2 is electrically connected to the other end of resistor R3 and pin 1 of voltage regulator U3. Pin 2 of voltage regulator U3 is electrically connected to the other end of resistor R5, one end of resistor R7, and one end of resistor R6. Pin 3 of voltage regulator U3 is electrically connected to the other end of resistor R6. Pin 3 of voltage regulator U3 is connected to signal ground. The other end of resistor R7 is electrically connected to pin 1 of MOSFET Q1. The MOSFET Q1 has its pin 3 electrically connected to one end of resistor R8 and one end of resistor R9. Its pin 2 is electrically connected to the other end of resistor R8, pin 3 of voltage regulator U4, one end of resistor R12, and one end of resistor R13. Pin 3 of voltage regulator U4 is connected to signal ground. The other end of resistor R9 is electrically connected to one end of resistor R10 and pin 1 of voltage regulator U4. The other end of resistor R10 is electrically connected to one end of resistor R11, which is connected to 12V+. The other end of resistor R11 is electrically connected to one end of thermistor RT2. The other end of thermistor RT2 is electrically connected to pin 2 of voltage regulator U4, the other end of resistor R12, and the other end of resistor R13.

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