Overheat protection circuit of control panel

Abstract

The utility model discloses an overheating protection circuit of a control panel, which comprises a temperature detection comparison circuit, a voltage reduction circuit, a heat dissipation device and a power-off protection switch which are electrically connected with an MCU (Microprogrammed Control Unit) main control chip, the MCU main control chip comprises a temperature judgment control module, and the power-off protection switch is electrically connected with a load. According to the utility model, through cooperation of the temperature detection comparison circuit, the temperature determination control module, the heat dissipation device and the step-down circuit, temperature adjustment control can be carried out on the control panel in a step-down and auxiliary heat dissipation mode when the temperature of the control panel is in a controllable range, and a power supply does not need to be directly cut off, so that normal work of the control panel is not influenced.

Description

Technical Field

[0001] This utility model relates to the field of overheat protection circuit technology, and in particular to an overheat protection circuit for a control board. Background Technology

[0002] The control board generates heat during operation due to the internal components and circuitry. Excessive heat accelerates the aging of the controller components and shortens the lifespan of the equipment. Therefore, control boards are generally equipped with overheat protection circuits. Existing overheat protection circuits typically disconnect the power supply to the control board when they detect that the temperature is too high, failing to provide timely cooling within a controllable temperature range. Directly cutting off the power and stopping operation within a controllable temperature range affects the efficiency of the control board. Therefore, this application proposes an overheat protection circuit for the control board. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing an overheat protection circuit for a control board.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] An overheat protection circuit for a control board includes a temperature detection and comparison circuit, a step-down circuit, a heat dissipation device, and a power-off protection switch electrically connected to an MCU main control chip. The MCU main control chip includes a temperature judgment and control module, and the power-off protection switch is electrically connected to a load.

[0006] The temperature detection comparison circuit includes a comparator U. Pin 1 of comparator U is electrically connected to one end of resistor R4. The other end of resistor R4 is electrically connected to the cathode of diode D3. The anode of diode D3 is electrically connected to one end of resistor R1. The other end of resistor R1 is electrically connected to one end of resistor R2, pin 1 of operational amplifier A, and the cathode of diode D4. The other end of resistor R2 is electrically connected to the cathode of diode D2 and one end of resistor R3. The other end of resistor R3 is electrically connected to pin 2 of comparator U. The anode of diode D2 is electrically connected to the cathode of diode D1. The anode of diode D1 is electrically connected to the input pin of the MCU main control chip. The cathode of diode D2 is also... The collector of transistor Q1 is electrically connected. The base of transistor Q1 is electrically connected to pin 3 of operational amplifier A. Pin 2 of operational amplifier A is electrically connected to one end of resistor R7. The other end of resistor R7 is electrically connected to the emitter of transistor Q1. The emitter of transistor Q1 is electrically connected to one end of resistor R8. The other end of resistor R8 is electrically connected to the anode of diode D4. Pins 1 and 3 of comparator U are connected in parallel with resistor R6. Pin 3 of comparator U is electrically connected to one end of capacitor C1. The other end of capacitor C1 is electrically connected to the signal receiving pin of the MCU main control chip. Pin 2 of comparator U is also electrically connected to one end of resistor R5. The other end of resistor R5 is grounded.

[0007] Preferably, the step-down circuit includes a resistor-capacitor step-down circuit, a rectifier-filter circuit, and a voltage regulator circuit;

[0008] The RC step-down circuit includes capacitors C2 and C3. One end of capacitor C2 and one end of capacitor C3 are connected in series. The other end of capacitor C2 and the other end of capacitor C3 are connected in parallel with resistor R10. The other end of capacitor C2 is also electrically connected to one end of resistor R9 and the collector of transistor Q2. The base of transistor Q2 is electrically connected to the voltage input pin of the MCU main control chip. The emitter of transistor Q2 is electrically connected to the other end of resistor R9.

[0009] Preferably, the rectifier filter circuit includes a rectifier D6 and a capacitor C4. Pin 1 of the rectifier D6 is electrically connected to the other end of the capacitor C3 and one end of the resistor R10. Pin 3 of the rectifier D6 is electrically connected to the other end of the resistor R9 and the emitter of the transistor Q2. Pins 2 and 4 of the rectifier D6 are connected in parallel with the capacitor C4.

[0010] Preferably, the voltage regulator circuit includes a Zener diode D5 and a Zener diode D7, which are connected in parallel. Zener diode D5 is connected in parallel with capacitor C4. The positive terminals of both Zener diode D5 and Zener diode D7 are electrically connected to pin 2 of rectifier D6. The negative terminals of both Zener diode D5 and Zener diode D7 are electrically connected to pin 4 of rectifier D6. The positive terminals of both Zener diode D5 and Zener diode D7 are grounded. The positive and negative terminals of Zener diode D7 are electrically connected to the load.

[0011] Preferably, the heat dissipation device is a heat sink, and a control switch is electrically connected between the heat sink and the MCU main control chip, which is used to dissipate heat and cool the control board.

[0012] Preferably, diodes D1 and D2 constitute a temperature sampler for acquiring the temperature of the MCU main control chip. Operational amplifier A is used to amplify the temperature signals acquired by diodes D1 and D2. Transistor Q1 is used to stabilize the current of diodes D1 and D2. Comparator U is used to compare the acquired temperature with the set overheat protection threshold. If the temperature exceeds the threshold, a high level is output to the MCU main control chip.

[0013] Preferably, the rectifier D6 and capacitor C4 are used to rectify and filter the input voltage. The rectifier D6 is a full-wave rectifier, which consists of four diodes connected in series.

[0014] Preferably, the control logic of the temperature judgment and control module is as follows: when the temperature is within the controllable threshold range, the heat dissipation device and the step-down circuit are controlled to work to perform cooling treatment; when the temperature exceeds the controllable threshold range, the power-off protection switch is activated to directly disconnect the power supply.

[0015] Compared with existing technologies, the beneficial effects of this utility model are:

[0016] This invention combines a temperature detection and comparison circuit, a temperature judgment and control module, a heat dissipation device, and a step-down circuit to regulate the temperature of the control board by stepping down the voltage and providing auxiliary heat dissipation when the temperature of the control board is within a controllable range. This does not require directly cutting off the power supply and thus does not affect the normal operation of the control board. Attached Figure Description

[0017] Figure 1 This is a connection block diagram of an overheat protection circuit for a control board proposed in this utility model.

[0018] Figure 2 The circuit diagram of the temperature detection and comparison circuit of the overheat protection circuit of the control board proposed in this utility model;

[0019] Figure 3The circuit diagram shows the connection between the step-down circuit of the overheat protection circuit of the control board and the MCU main control chip proposed in this utility model. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Reference Figure 1-3 An overheat protection circuit for a control board includes a temperature detection and comparison circuit, a step-down circuit, a heat dissipation device, and a power-off protection switch, all electrically connected to an MCU main control chip. The heat dissipation device is a heat sink, and a control switch is electrically connected between the heat sink and the MCU main control chip for cooling the control board. The MCU main control chip includes a temperature judgment and control module. The control logic of the temperature judgment and control module is as follows: when the temperature is within a controllable threshold range, the heat dissipation device and the step-down circuit are controlled to work to perform cooling; when the temperature exceeds the controllable threshold range, the power-off protection switch is controlled to open and directly disconnect the power supply. The power-off protection switch is electrically connected to a load.

[0022] The temperature detection comparison circuit includes comparator U. Pin 1 of comparator U is electrically connected to one end of resistor R4. The other end of resistor R4 is electrically connected to the cathode of diode D3. The anode of diode D3 is electrically connected to one end of resistor R1. The other end of resistor R1 is electrically connected to one end of resistor R2, pin 1 of operational amplifier A, and the cathode of diode D4. The other end of resistor R2 is electrically connected to the cathode of diode D2 and one end of resistor R3. The other end of resistor R3 is electrically connected to pin 2 of comparator U. The anode of diode D2 is electrically connected to the cathode of diode D1. The anode of diode D1 is electrically connected to the input pin of the MCU main control chip. The cathode of diode D2 is also electrically connected to... The collector of transistor Q1 is connected to the base of transistor Q1, which is electrically connected to pin 3 of operational amplifier A. Pin 2 of operational amplifier A is electrically connected to one end of resistor R7, and the other end of resistor R7 is electrically connected to the emitter of transistor Q1. The emitter of transistor Q1 is electrically connected to one end of resistor R8, and the other end of resistor R8 is electrically connected to the anode of diode D4. Pins 1 and 3 of comparator U are connected in parallel with resistor R6. Pin 3 of comparator U is electrically connected to one end of capacitor C1, and the other end of capacitor C1 is electrically connected to the signal receiving pin of the MCU main control chip. Pin 2 of comparator U is also electrically connected to one end of resistor R5, and the other end of resistor R5 is grounded.

[0023] Diodes D1 and D2 form a temperature sampler to collect the temperature of the MCU main control chip. Operational amplifier A is used to amplify the temperature signal collected by diodes D1 and D2. Transistor Q1 is used to stabilize the current of diodes D1 and D2. Comparator U is used to compare the collected temperature with the set overheat protection threshold. If the temperature exceeds the threshold, a high level is output to the MCU main control chip.

[0024] A step-down circuit includes an RC step-down circuit, a rectifier and filter circuit, and a voltage regulator circuit.

[0025] The RC step-down circuit includes capacitors C2 and C3. One end of capacitor C2 and one end of capacitor C3 are connected in series. The other end of capacitor C2 and the other end of capacitor C3 are connected in parallel with resistor R10. The other end of capacitor C2 is also electrically connected to one end of resistor R9 and the collector of transistor Q2. The base of transistor Q2 is electrically connected to the voltage input pin of the MCU main control chip. The emitter of transistor Q2 is electrically connected to the other end of resistor R9.

[0026] The rectifier and filter circuit includes rectifier D6 and capacitor C4. Pin 1 of rectifier D6 is electrically connected to the other end of capacitor C3 and one end of resistor R10. Pin 3 of rectifier D6 is electrically connected to the other end of resistor R9 and the emitter of transistor Q2. Pins 2 and 4 of rectifier D6 are connected in parallel with capacitor C4. Rectifier D6 and capacitor C4 are used to rectify and filter the input voltage. Rectifier D6 is a full-wave rectifier, which is composed of four diodes connected in series.

[0027] The voltage regulator circuit includes Zener diodes D5 and D7, which are connected in parallel. Zener diode D5 is also connected in parallel with capacitor C4. The anodes of both Zener diodes D5 and D7 are electrically connected to pin 2 of rectifier D6, and the cathodes of both are electrically connected to pin 4 of rectifier D6. The anodes of both Zener diodes D5 and D7 are grounded, and both the anode and cathode of Zener diode D7 are electrically connected to the load. This invention, through the cooperation of a temperature detection and comparison circuit, a temperature judgment and control module, a heat dissipation device, and a step-down circuit, can regulate the temperature of the control board by stepping down the voltage and providing auxiliary heat dissipation when the temperature of the control board is within a controllable range, without directly cutting off the power supply, thus not affecting the normal operation of the control board.

[0028] Working principle: During the operation of the control board, the temperature of the MCU main control chip is collected by diodes D1 and D2 in the temperature detection and comparison circuit. Operational amplifier A amplifies the collected temperature signal, and comparator U compares the amplified temperature signal with the set overheat protection threshold. If the threshold is exceeded, a high level is output to the MCU main control chip. The temperature judgment and control module of the MCU main control chip judges the temperature value according to the control logic. When the temperature exceeds the threshold of the controllable range, the power-off protection switch is activated to directly disconnect the power supply, thereby achieving direct power-off overheat protection.

[0029] When the temperature is within a controllable threshold, the MCU main control chip controls the heat dissipation device to turn on for cooling via a control switch. Simultaneously, the MCU main control chip controls transistor Q2 to conduct, and the input voltage of the MCU main control chip enters the RC step-down circuit. The RC step-down circuit reduces the input voltage, and the reduced voltage is then rectified and filtered by a rectifier and filter circuit. The rectified and filtered voltage is then regulated by a voltage regulator circuit, and the regulated output voltage is a stable stepped-down voltage to power the load. By reducing the voltage, the heat generated by the control board can be effectively reduced. Combined with the cooling treatment of the heat dissipation device, the temperature of the control board can be effectively regulated, achieving the purpose of temperature regulation protection of the control board in case of overheating. This temperature regulation protection method does not require direct power cut-off, thus not affecting the normal operation of the control board.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An overheat protection circuit for a control board, characterized in that, It includes a temperature detection and comparison circuit, a step-down circuit, a heat dissipation device, and a power failure protection switch that are electrically connected to the MCU main control chip. The MCU main control chip includes a temperature judgment and control module, and the power failure protection switch is electrically connected to a load. The temperature detection comparison circuit includes a comparator U. Pin 1 of comparator U is electrically connected to one end of resistor R4. The other end of resistor R4 is electrically connected to the cathode of diode D3. The anode of diode D3 is electrically connected to one end of resistor R1. The other end of resistor R1 is electrically connected to one end of resistor R2, pin 1 of operational amplifier A, and the cathode of diode D4. The other end of resistor R2 is electrically connected to the cathode of diode D2 and one end of resistor R3. The other end of resistor R3 is electrically connected to pin 2 of comparator U. The anode of diode D2 is electrically connected to the cathode of diode D1. The anode of diode D1 is electrically connected to the input pin of the MCU main control chip. The cathode of diode D2 is also... The collector of transistor Q1 is electrically connected. The base of transistor Q1 is electrically connected to pin 3 of operational amplifier A. Pin 2 of operational amplifier A is electrically connected to one end of resistor R7. The other end of resistor R7 is electrically connected to the emitter of transistor Q1. The emitter of transistor Q1 is electrically connected to one end of resistor R8. The other end of resistor R8 is electrically connected to the anode of diode D4. Pins 1 and 3 of comparator U are connected in parallel with resistor R6. Pin 3 of comparator U is electrically connected to one end of capacitor C1. The other end of capacitor C1 is electrically connected to the signal receiving pin of the MCU main control chip. Pin 2 of comparator U is also electrically connected to one end of resistor R5. The other end of resistor R5 is grounded.

2. The overheat protection circuit for a control board according to claim 1, characterized in that, The step-down circuit includes a resistor-capacitor step-down circuit, a rectifier-filter circuit, and a voltage regulator circuit; The RC step-down circuit includes capacitors C2 and C3. One end of capacitor C2 and one end of capacitor C3 are connected in series. The other end of capacitor C2 and the other end of capacitor C3 are connected in parallel with resistor R10. The other end of capacitor C2 is also electrically connected to one end of resistor R9 and the collector of transistor Q2. The base of transistor Q2 is electrically connected to the voltage input pin of the MCU main control chip. The emitter of transistor Q2 is electrically connected to the other end of resistor R9.

3. The overheat protection circuit for a control board according to claim 2, characterized in that, The rectifier and filter circuit includes a rectifier D6 and a capacitor C4. Pin 1 of the rectifier D6 is electrically connected to the other end of the capacitor C3 and one end of the resistor R10. Pin 3 of the rectifier D6 is electrically connected to the other end of the resistor R9 and the emitter of the transistor Q2. Pins 2 and 4 of the rectifier D6 are connected in parallel with the capacitor C4.

4. The overheat protection circuit for a control board according to claim 3, characterized in that, The voltage regulator circuit includes Zener diodes D5 and D7, which are connected in parallel. Zener diode D5 is also connected in parallel with capacitor C4. The anodes of both Zener diodes D5 and D7 are electrically connected to pin 2 of rectifier D6, and the cathodes of both Zener diodes D5 and D7 are electrically connected to pin 4 of rectifier D6. The anodes of both Zener diodes D5 and D7 are grounded, and both the anode and cathode of Zener diode D7 are electrically connected to the load.

5. The overheat protection circuit for a control board according to claim 1, characterized in that, The heat dissipation device is a heat sink, and a control switch is electrically connected between the heat sink and the MCU main control chip, which is used to dissipate heat and cool the control board.

6. The overheat protection circuit for a control board according to claim 1, characterized in that, Diodes D1 and D2 form a temperature sampler for acquiring the temperature of the MCU main control chip. Operational amplifier A amplifies the temperature signals acquired by diodes D1 and D2. Transistor Q1 stabilizes the current of diodes D1 and D2. Comparator U compares the acquired temperature with the set overheat protection threshold. If the temperature exceeds the threshold, a high level is output to the MCU main control chip.

7. The overheat protection circuit for a control board according to claim 3, characterized in that, The rectifier D6 and capacitor C4 are used to rectify and filter the input voltage. The rectifier D6 is a full-wave rectifier, which consists of four diodes connected in series.

8. The overheat protection circuit for a control board according to claim 1, characterized in that, The control logic of the temperature judgment and control module is as follows: when the temperature is within the controllable threshold range, the heat dissipation equipment and the step-down circuit are controlled to work to perform cooling treatment; when the temperature exceeds the controllable threshold range, the power-off protection switch is activated to directly disconnect the power supply.

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