Temperature sensor detection circuit with risk control function and control method thereof

Abstract

The invention discloses a temperature sensor detection circuit with a risk control function and a control method thereof, which are used for carrying out dynamic safety detection on various temperature sensors, an input end of an operational amplifier proportion circuit is connected with a third connecting end of a first operational amplifier, and a second connecting end of the first operational amplifier is grounded; a first connecting end of the first operational amplifier serves as an output end of the operational amplifier proportion circuit and is connected with an input end of the comparator circuit; the input end of the comparator circuit is connected with the sixth connecting end of the second comparator, the fifth connecting end of the second comparator serves as the input end of the comparator circuit, and the seventh connecting end of the second comparator is externally connected with a power supply and is connected with the output end of the comparator circuit; the input end of the fan driving circuit is connected with the output end of the comparator circuit, the input end of the comparator circuit is connected with the base electrode of the third triode, the problems caused by non-uniform temperature sensor types and electrified device detection are solved, and the safety and reliability of equipment are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent electrical technology, and in particular to a temperature sensor detection circuit with a risk control function and a control method thereof. Background Art

[0002] Existing technologies often face numerous challenges in the cooling systems used in electrical equipment control circuits. Different devices require multiple types of temperature sensors, such as KTY84 and PT100, but existing technologies lack effective multi-sensor compatibility solutions, resulting in complex and inflexible systems. Traditional mechanical sensor switching methods suffer from low reliability and slow response, impacting system performance. Furthermore, failure of the cooling fan can cause equipment overheating or even fire, yet existing technologies lack effective fan operation monitoring and fault response mechanisms. Furthermore, temperature sensor disconnections and short circuits cannot be detected and addressed promptly, further increasing equipment operational risks. Summary of the Invention

[0003] The embodiments of the present invention provide a temperature sensor detection circuit with risk control function and a control method thereof, aiming to solve the problem of poor fan drive stability caused by the circuit temperature detection process in the prior art methods.

[0004] In a first aspect, an embodiment of the present invention discloses a temperature sensor detection circuit with a risk control function. The temperature sensor detection circuit with a risk control function is used to perform dynamic safety detection on multiple temperature sensors. The detection circuit includes an operational amplifier proportional circuit, a comparator circuit, and a fan drive circuit; the input end of the operational amplifier proportional circuit is connected to the third connection end of the first operational amplifier, the second connection end of the first operational amplifier is grounded, and the first connection end of the first operational amplifier is connected to the input end of the comparator circuit as the output end of the operational amplifier proportional circuit; the input end of the comparator circuit is connected to the sixth connection end of the second comparator, the fifth connection end of the second comparator serves as the input end of the comparator circuit, and the seventh connection end of the second comparator is connected to an external power supply and connected to the output end of the comparator circuit; the input end of the fan drive circuit is connected to the output end of the comparator circuit, the input end of the comparator circuit is connected to the base of the third transistor, the collector of the third transistor is connected to the base of the fourth transistor, the emitter of the third transistor is connected to the emitter of the fourth transistor and is grounded; the emitter of the fourth transistor is connected to the first connection end of the pin header, and the second connection end of the pin header is connected to the collector of the fourth transistor.

[0005] Furthermore, the operational amplifier proportional circuit includes a sixth transistor and a fifty-first capacitor, the base of the sixth transistor is connected to the input power supply, the emitter of the sixth transistor is grounded, the collector of the sixth transistor is connected to the second connection terminal of the first operational amplifier, the fifty-first capacitor is connected to the first operational amplifier in parallel, one end of the fifty-first capacitor is connected to the collector of the sixth transistor, and the other end is connected to the first connection terminal of the first operational amplifier.

[0006] Furthermore, the detection circuit also includes a reference circuit, which includes a fourth voltage-stabilizing diode, a sixty-second capacitor and a sixty-fourth capacitor. The positive pole of the fourth voltage-stabilizing diode is grounded, the negative pole of the fourth voltage-stabilizing diode is connected to the comparator circuit through the power supply connection end, and the sixty-second capacitor and the sixty-fourth capacitor are connected in parallel with the fourth voltage-stabilizing diode.

[0007] Furthermore, the detection circuit also includes an optocoupler circuit, which includes an optocoupler, a sixty-fifth resistor and a sixty-sixth resistor. The first connection end of the optocoupler is connected to the power supply connection end through the sixty-fifth resistor, the second connection end of the optocoupler is connected to the first connection end of the operational amplifier, the sixty-sixth resistor is connected in parallel with the sixty-fifth resistor, one end of the sixty-sixth resistor is connected to the first end of the operational amplifier, the third connection end of the optocoupler is grounded, and the fourth connection end of the optocoupler is grounded.

[0008] Furthermore, the fan drive circuit includes a fan drive module, the base of the third transistor is connected to the output end of the comparator circuit, the collector of the third transistor is connected to the base of the fourth transistor, the emitter of the third transistor is connected to the pin header and grounded, the collector of the fourth transistor is connected to the fan drive module, and the emitter of the fourth transistor is connected to the pin header and grounded.

[0009] Furthermore, a voltage threshold of the power supply connection terminal to which the reference circuit is connected is set to 15V.

[0010] Furthermore, the comparator circuit also includes a first comparator and a second operational amplifier, the positive pole of the first comparator is grounded, the negative pole of the first comparator is connected to the power supply connection terminal, the second connection terminal of the first comparator is connected to the output terminal of the operational amplifier proportional circuit, the third connection terminal of the first comparator is connected to the external power supply, the seventh connection terminal of the second operational amplifier is connected to the base of the seventh transistor, the collector of the seventh transistor is connected to the second connection terminal of the optocoupler, and the fifth connection terminal of the second operational amplifier circuit is connected to the power supply connection terminal.

[0011] Furthermore, the fan drive circuit also includes an 82nd diode, the anode of the 82nd diode is connected to the collector of the fourth transistor, and the cathode of the 82nd diode is connected to the fan drive module.

[0012] Furthermore, the comparator circuit also includes a fifty-third capacitor, one end of the fifty-third capacitor is connected to the fifth connection terminal of the second comparator, and the other end of the fifty-third capacitor is grounded.

[0013] In the second aspect, an embodiment of the present invention discloses a control method for a temperature sensor detection circuit with a risk control function, characterized in that the control method is applied to the temperature sensor detection circuit with a risk control function of any one of claims 1 to 9 above, and the control method includes using an operational amplifier proportional circuit to generate a control electrical signal through the first operational amplifier included therein, and outputting the control electrical signal to the fan drive circuit through a comparator circuit to perform fan drive control; the comparator circuit performs electrical signal comparison control processing and electrical signal output according to the control electrical signal; the fan drive circuit performs fan drive control according to the control electrical signal after comparison control processing by the comparator circuit.

[0014] The circuit and its control method achieve compatibility with both KTY84 and PT100 sensors through circuit design, simplifying the circuit structure and reducing costs and failure risks. Fault detection and emergency response can detect sensor short circuits, open circuits, and overtemperature faults. When a fault occurs, the fan continues to operate and reports the fault, effectively preventing the risk of equipment overheating or fire caused by sensor failure. The circuit's isolation function ensures safe detection of sensors installed in live devices, enabling hysteresis-controlled automatic fan control, preventing frequent fan starts and stops at critical temperature points and extending fan life. The design of pin header J21 allows manual fan operation in the event of an operational amplifier or comparator circuit anomaly, ensuring continued device operation during control board replacement. Overall, this technical solution effectively addresses issues arising from inconsistent temperature sensor types, sensor failures, and live device detection, enabling accurate detection and effective control of device temperature, and improving equipment safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic diagram of the overall structure of a temperature sensor detection circuit with risk control function provided by an embodiment of the present invention; Figure 2 A schematic diagram of a partial structure of a temperature sensor detection circuit with a risk control function provided by an embodiment of the present invention; Figure Number: 1. Operational amplifier proportional circuit; 11. First operational amplifier; 12. Sixth transistor; 13. Fifty-first capacitor; 2. Comparator circuit; 21. First comparator; 22. Second comparator; 23. Second operational amplifier; 24. Seventh transistor; 25. Fifty-third capacitor; 3. Fan drive circuit; 31. Third transistor; 32. Fourth transistor; 36. Fan drive module; 37. Eighty-second diode; 4. Pin header; 5. Reference circuit; 51. Fourth voltage regulator diode; 52. Sixty-second capacitor; 53. Sixty-fourth capacitor; 54. Power supply connection terminal; 6. Optocoupler circuit; 61. Optocoupler; 62. Sixty-fifth resistor; 63. Sixty-sixth resistor. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0019] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should be further understood that the term "and / or" used in the present description and appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0021] like Figure 1 and Figure 2As shown, in the first aspect, the temperature sensor detection circuit with risk control function provided by the present embodiment is used to perform dynamic safety detection on multiple temperature sensors. The detection circuit includes an operational amplifier proportional circuit 1, a comparator circuit 2 and a fan drive circuit 64; the input end of the operational amplifier proportional circuit 1 is connected to the third connection end of the first operational amplifier 11, the second connection end of the first operational amplifier 11 is grounded, and the first connection end of the first operational amplifier 11 is connected to the input end of the comparator circuit 2 as the output end of the operational amplifier proportional circuit 1; the input end of the comparator circuit 2 is connected to the sixth end of the second comparator 22. The fifth connection terminal of the second comparator 22 serves as the input terminal of the comparator circuit 2, and the seventh connection terminal of the second comparator 22 is connected to the external power supply and is connected to the output terminal of the comparator circuit 2; the input terminal of the fan drive circuit 64 is connected to the output terminal of the comparator circuit 2, the input terminal of the comparator circuit 2 is connected to the base of the third transistor 31, the collector of the third transistor 31 is connected to the base of the fourth transistor 32, the emitter of the third transistor 31 is connected to the emitter of the fourth transistor 32 and is grounded; the emitter of the fourth transistor 32 is connected to the first connection terminal of the pin header 4, and the second connection terminal of the pin header 4 is connected to the collector of the fourth transistor 32.

[0022] In practical scenarios, this solution, through the design of op amp proportional circuit 1, can accommodate different types of temperature sensors (such as KTY84 and PT100), addressing multi-sensor compatibility issues. It implements dynamic safety detection for multiple temperature sensors, ensuring real-time monitoring of temperature changes and preventing overheating. The combination of op amp proportional circuit 1 and comparator circuit 2 enables precise temperature detection and control. The design of comparator circuit 2 enables rapid response and triggering of fan drive circuit 64 to maintain fan operation and prevent equipment overheating in the event of a sensor short or open circuit. The circuit design incorporates isolation, ensuring safe detection of sensors installed in live devices. Pin header 4 and transistors provide a manual emergency response, ensuring continued fan operation in the event of a circuit anomaly. Electronic switching and an isolated circuit design simplify the circuit structure, reduce on-board components and failure points, and improve the reliability and stability of the entire detection circuit. This enables unified management of multiple temperature sensors and enhances detection efficiency. The dynamic detection function ensures real-time monitoring of temperature changes, effectively preventing overheating risks. The cooperation of the operational amplifier proportional circuit 1 and the comparator circuit 2 realizes the precise control of temperature and avoids equipment failure caused by temperature fluctuations. In the event of a sensor failure, the circuit can respond quickly and start the fan, ensuring the safe operation of the equipment. The isolation design improves the safety performance of the circuit and prevents the spread of electrical faults. The simplified circuit design reduces the number of failure points and improves the overall reliability of the system. Manual emergency measures provide additional safety guarantees and ensure the continuous operation of the equipment when the circuit is abnormal. The intelligent design of the circuit realizes automatic temperature detection and control, reducing the need for manual intervention. Hysteresis control avoids frequent starting and stopping of the fan and extends the service life of the fan. In summary, the temperature sensor detection circuit with risk control function provided in this embodiment effectively solves technical problems in multi-sensor compatibility, dynamic detection, precise control, fault response and safety through careful circuit design and function implementation, and achieves efficient, accurate, safe and reliable temperature detection and control effects.

[0023] In summary, the above-described embodiments effectively address the compatibility issues of different temperature sensors (such as KTY84 and PT100), enabling unified management and dynamic safety monitoring of multiple sensors. Through the collaboration of op amp proportional circuit 1 and comparator circuit 2, precise temperature detection and control are achieved, ensuring that the device operates within a safe temperature range. A rapid response mechanism is designed to immediately trigger fan drive circuit 64 in the event of a sensor short circuit or open circuit, ensuring fan operation and preventing device overheating and potential safety risks. Circuit isolation is implemented, enhancing the safety detection capabilities of sensors installed in live devices. Simultaneously, the circuit structure is simplified, reducing on-board components and failure points, and improving the reliability and stability of the entire detection circuit. A manual emergency response is provided to ensure continued fan operation in the event of an operational amplifier circuit or comparator circuit 2 malfunction, ensuring safe use of the device during control board replacement. Addressing these core technical issues enables this temperature sensor detection circuit to excel in multi-sensor compatibility, precise control, fault response, safety protection, and system reliability, effectively improving the safety and stability of the device.

[0024] Furthermore, the operational amplifier proportional circuit 1 includes a sixth transistor 12 and a fifty-first capacitor 13, the base of the sixth transistor 12 is connected to the input power supply, the emitter of the sixth transistor 12 is grounded, the collector of the sixth transistor 12 is connected to the second connection terminal of the first operational amplifier 11, the fifty-first capacitor 13 is connected in parallel with the first operational amplifier 11, one end of the fifty-first capacitor 13 is connected to the collector of the sixth transistor 12, and the other end is connected to the first connection terminal of the first operational amplifier 11.

[0025] Furthermore, the detection circuit also includes a reference circuit 5, which includes a fourth voltage-stabilizing diode 51, a sixty-second capacitor 52 and a sixty-fourth capacitor 53. The positive pole of the fourth voltage-stabilizing diode 51 is grounded, and the negative pole of the fourth voltage-stabilizing diode 51 is connected to the comparator circuit 2 through the power supply connection terminal 54. The sixty-second capacitor 52 and the sixty-fourth capacitor 53 are connected in parallel with the fourth voltage-stabilizing diode 51.

[0026] Specifically, the base of the sixth transistor 12 is connected to the input power supply, the emitter is grounded, and the collector is connected to the second connection terminal of the first operational amplifier 11, forming a stable bias circuit, providing a stable reference voltage for the operational amplifier. The fifty-first capacitor 13 is connected in parallel with the first operational amplifier 11, playing a role of filtering and decoupling, further improving the stability and anti-interference ability of the operational amplifier circuit, and ensuring the accuracy of temperature detection. The positive pole of the fourth voltage-stabilizing diode 51 is grounded, and the negative pole is connected to the comparator circuit 2 through the power supply connection terminal 54, providing a stable reference voltage for the comparator circuit 2. The sixty-second capacitor 52 and the sixty-fourth capacitor 53 are connected in parallel with the fourth voltage-stabilizing diode 51, playing a role of filtering and energy storage, further improving the stability and reliability of the reference voltage, and ensuring the accurate judgment of the comparator circuit 2. By adding the sixth transistor 12 and the fifty-first capacitor 13, the stability and anti-interference ability of the operational amplifier proportional circuit 1 are improved, ensuring the accuracy of temperature detection in a complex electromagnetic environment. By designing an independent reference circuit 5 and employing a combination of a voltage-stabilizing diode and capacitor, the stability and reliability of the reference voltage are ensured, providing an accurate reference baseline for comparator circuit 2 and improving the accuracy of fault detection. By optimizing the design of op amp proportional circuit 1 and reference circuit 5, the performance of the entire detection circuit is improved, ensuring accurate and stable temperature detection and control under various operating conditions. In summary, this solution, based on further refinement of the circuit design, addresses core technical issues such as circuit stability, anti-interference capability, reference voltage stability, and overall performance optimization, providing the device with safer, more reliable, and more efficient temperature detection and control capabilities.

[0027] Furthermore, the detection circuit also includes an optocoupler circuit 6, which includes an optocoupler 61, a sixty-fifth resistor 62 and a sixty-sixth resistor 63. The first connection end of the optocoupler 61 is connected to the power supply connection end 54 through the sixty-fifth resistor 62, the second connection end of the optocoupler 61 is connected to the first connection end of the operational amplifier, the sixty-sixth resistor 63 is connected in parallel with the sixty-fifth resistor 62, one end of the sixty-sixth resistor 63 is connected to the first end of the operational amplifier, the third connection end of the optocoupler 61 is grounded, and the fourth connection end of the optocoupler 61 is grounded.

[0028] Furthermore, the fan drive circuit 64 includes a third transistor 31, a fourth transistor 32 and a fan drive module 36, the base of the third transistor 31 is connected to the output end of the comparator circuit 2, the collector of the third transistor 31 is connected to the base of the fourth transistor 32, the emitter of the third transistor 31 is connected to the pin 4 and grounded, the collector of the fourth transistor 32 is connected to the fan drive module 36, and the emitter of the fourth transistor 32 is connected to the pin 4 and grounded.

[0029] Specifically, the introduction of the optocoupler circuit 6 achieves electrical isolation, effectively preventing high voltage from interfering with the low-voltage control circuit and improving the safety of the circuit. The sixty-fifth resistor 62 and the sixty-sixth resistor 63 cooperate with the optocoupler 61 to achieve stable signal transmission and isolation. The sixty-fifth resistor 62 connects the reference voltage to the first connection terminal of the optocoupler 61, ensuring the stability of the input signal of the optocoupler 61; the sixty-sixth resistor 63 is connected in parallel with the optocoupler 61, playing the role of voltage division and current limiting, further protecting the optocoupler 61 and the operational amplifier. The cascade design of the third transistor 31 and the fourth transistor 32 achieves reliable control of the fan drive module 36. The output end of the comparator circuit 2 controls the base of the third transistor 31, and the base of the fourth transistor 32 is controlled by the conduction and cutoff of the third transistor 31, thereby controlling the working state of the fan drive module 36. The design of the pin header 4 not only realizes the connection of the circuit, but also provides a manual emergency measure when the circuit is abnormal. By short-circuiting pin header 4, the fan can be forced into operation, ensuring safe operation during control board replacement or circuit anomalies. The design of optocoupler circuit 6 isolates high and low voltage circuits, effectively preventing high-voltage interference and potential safety risks. The combination of optocoupler 61 and resistors ensures signal stability and reliability during isolated transmission, avoiding signal distortion or interference. Through cascade control of transistors, precise and reliable control of fan driver module 36 is achieved, ensuring the fan can be started and operated promptly when needed. Pin header 4 provides a manual emergency response, enhancing the system's emergency response capabilities in abnormal situations and ensuring the continued safe operation of the equipment. By utilizing optocoupler 61 for isolation, stable signal transmission, optimized fan drive control logic, and enhanced emergency response capabilities, the entire temperature sensor detection circuit significantly improves safety and reliability. The circuit automatically detects temperature changes and activates the fan when a set threshold is reached. It also provides fault detection and emergency response capabilities, achieving highly intelligent and automated temperature control. Circuit design and maintenance are simplified, with a clear circuit structure and modular functions, facilitating subsequent maintenance and upgrades. Based on further refinement of the circuit design, this solution solves core technical issues such as circuit isolation, signal transmission, fan drive control, and emergency handling, providing the equipment with safer, more reliable, intelligent, and efficient temperature detection and control functions.

[0030] Furthermore, the voltage threshold of the power supply connection terminal 54 to which the reference circuit 5 is connected is set to 15V.

[0031] Furthermore, the comparator circuit 2 also includes a first comparator 21 and a second operational amplifier 23, the positive electrode of the first comparator 21 is grounded, the negative electrode of the first comparator 21 is connected to the power supply connection terminal 54, the second connection terminal of the first comparator 21 is connected to the output terminal of the operational amplifier proportional circuit 1, the third connection terminal of the first comparator 21 is connected to the external power supply, the seventh connection terminal of the second operational amplifier 23 is connected to the base of the seventh transistor 24, the collector of the seventh transistor 24 is connected to the second connection terminal of the optocoupler 61, and the fifth connection terminal of the second operational amplifier circuit is connected to the power supply connection terminal 54.

[0032] Furthermore, the fan drive circuit 64 also includes an eighty-second diode 37 , the anode of the eighty-second diode 37 is connected to the collector of the fourth transistor 32 , and the cathode of the eighty-second diode 37 is connected to the fan drive module 36 .

[0033] Specifically, the voltage threshold of the power supply connection terminal 54 of the reference circuit 5 is set to 15V, providing a stable, high-precision reference voltage for the entire detection circuit and ensuring the accuracy of the comparator circuit 2 in determining the temperature threshold. The positive terminal of the first comparator 21 is grounded, and the negative terminal is connected to the reference voltage, enabling comparison of the voltage at the output of the operational amplifier proportional circuit 1. The second terminal of the first comparator 21 is connected to the output of the operational amplifier proportional circuit 1, ensuring the accuracy of the comparison. The second operational amplifier 23 and the seventh transistor 24 cooperate to further process and amplify the signal, providing a suitable drive current for the optocoupler 61 and ensuring effective signal transmission. The positive terminal of the eighty-second diode 37 is connected to the collector of the fourth transistor 32, and the negative terminal is connected to the fan drive module 36. This provides freewheeling and reverse voltage protection, preventing reverse voltage generated by the fan drive module 36 when it is turned off from damaging the circuit and enhancing the stability and reliability of the fan drive circuit 64. By setting a specific voltage threshold (15V), the stability and accuracy of the reference voltage are ensured, providing a foundation for accurate detection and control of the entire circuit. The combined use of the first comparator 21 and the second operational amplifier 23 enables accurate signal processing and comparison, improving the circuit's response speed and accuracy to temperature changes. The addition of the eighty-second diode 37 provides additional protection for the fan drive circuit 64, preventing damage to the circuit due to reverse voltage, and extending the service life of the circuit and the fan. The precise setting of the reference voltage and the optimized design of the comparator circuit 2 make temperature detection and control more accurate, effectively avoiding false operations and missed detections. By adding protective elements such as diodes, the circuit's ability to withstand abnormal voltages and currents is enhanced, improving the circuit's stability and reliability. The combined use of the comparator circuit 2 and the operational amplifier enables complex signal processing and logical judgment, providing support for intelligent temperature control. In summary, this solution, based on further refinement of the circuit design, solves core technical problems such as reference voltage stability, signal processing accuracy, comparison logic optimization, and fan drive protection, providing the equipment with more accurate, stable, reliable, and intelligent temperature detection and control functions.

[0034] Furthermore, the voltage threshold of the power supply connection terminal 54 to which the reference circuit 5 is connected is set to 15V.

[0035] Furthermore, the comparator circuit 2 also includes a first comparator 21 and a second operational amplifier 23, the positive electrode of the first comparator 21 is grounded, the negative electrode of the first comparator 21 is connected to the power supply connection terminal 54, the second connection terminal of the first comparator 21 is connected to the output terminal of the operational amplifier proportional circuit 1, the third connection terminal of the first comparator 21 is connected to the external power supply, the seventh connection terminal of the second operational amplifier 23 is connected to the base of the seventh transistor 24, the collector of the seventh transistor 24 is connected to the second connection terminal of the optocoupler 61, and the fifth connection terminal of the second operational amplifier circuit is connected to the power supply connection terminal 54.

[0036] Furthermore, the fan drive circuit 64 also includes an eighty-second diode 37 , the anode of the eighty-second diode 37 is connected to the collector of the fourth transistor 32 , and the cathode of the eighty-second diode 37 is connected to the fan drive module 36 .

[0037] Furthermore, the comparator circuit 2 further includes a fifty-third capacitor 25 , one end of the fifty-third capacitor 25 is connected to the fifth connection end of the second comparator 22 , and the other end of the fifty-third capacitor 25 is grounded.

[0038] Specifically, the voltage threshold of the power supply connection terminal 54 of the reference circuit 5 is stabilized at 15V, providing a precise reference point for the entire detection circuit and ensuring the accuracy of subsequent comparison and amplification circuits. The design of the first comparator 21 has its positive terminal grounded and its negative terminal connected to the reference voltage, enabling precise comparison of the output of the op-amp proportional circuit 1. The connection between the second operational amplifier 23 and the seventh transistor 24 provides stable drive for the optocoupler 61, ensuring effective signal transmission. The capacitor is connected to the fifth connection terminal of the second comparator 22, with its other end grounded, providing decoupling and filtering, further stabilizing the output of the comparator circuit 2 and reducing noise and interference. The diode provides freewheeling and reverse voltage protection in the fan drive circuit 64, preventing reverse voltage generated when the fan is turned off from damaging the circuit. The precise voltage threshold setting and stable reference circuit 5 design ensure a stable reference voltage for the entire detection circuit, providing a foundation for precise detection and control. Through the coordination of the first comparator 21, the second operational amplifier 23, and the fifty-third capacitor 25, precise comparison, amplification, and stable output of the signal are achieved, improving the circuit's response speed and accuracy. The introduction of the eighty-second diode 37 provides additional protection for the fan drive circuit 64 and enhances the reliability and stability of the circuit. The precise reference voltage and optimized comparator circuit 2 design make temperature detection and control more accurate, effectively avoiding false operations and missed detections. The addition of the fifty-third capacitor 25 effectively filters out the noise and interference of the comparator circuit 2, improving the stability and reliability of the circuit. The addition of the eighty-second diode 37 provides comprehensive protection for the fan, extends the service life of the fan, and improves the reliability of the entire system. In summary, this solution, based on further refinement of the circuit design, solves core technical problems such as reference voltage stability, comparator circuit 2 performance optimization, and fan drive protection, providing the equipment with more accurate, stable, reliable and intelligent temperature detection and control functions.

[0039] In a second aspect, embodiments of the present invention disclose a control method for a temperature sensor detection circuit with a risk control function. This control method is applicable to the aforementioned temperature sensor detection circuit with a risk control function. The control method includes generating a control electrical signal using an operational amplifier proportional circuit 1 via its first operational amplifier 11, and outputting the control electrical signal to a fan drive circuit 64 via a comparator circuit 2 for fan drive control. The comparator circuit 2 performs comparison control processing based on the control electrical signal and outputs the signal. The fan drive circuit 64 controls the fan drive based on the control electrical signal after the comparison control processing by the comparator circuit 2. The aforementioned circuit and control method are compatible with both KTY84 and PT100 temperature sensors and achieve isolated detection through electronic switching. The circuit primarily comprises the operational amplifier proportional circuit 1, the comparator circuit 2, the optocoupler circuit 6, the reference voltage circuit, and the fan drive circuit 64. Because temperature sensors used by clients or suppliers vary, this design achieves compatibility with both KTY84 and PT100 sensors through specialized circuit processing. This avoids the need for complex multi-processing circuits due to different sensor types, reducing on-board components and failure points. If the sensor shorts or opens, the circuit detects it and keeps the fan running while reporting the fault, ensuring equipment safety. Because the temperature sensor is installed in a live device, this circuit provides isolation, ensuring safe and accurate detection.

[0040] In the specific implementation process, as shown in the schematic diagram, the 70th resistor R70, the voltage regulator diode Z4, the 62nd capacitor C62, and the 64th capacitor C64 form a power supply D15V, which is a reference power supply generated by the voltage regulator tube. The power supply D2.5V_vRef is a reference power supply. Temp_SR is the input port of the sensor KTY84 or PT100. After the power supply D15V and the 50th resistor R50 and the 51st resistor R51 are divided, the voltage is filtered by the 54th resistor R54 and the 50th capacitor C50, and then enters the non-inverting input terminal of the first op amp. The sum of the values ​​of the 50th resistor R50 and the 51st resistor R51 is 4.7K, which is controlled by the temperature sensor connected in series. The current is within 4mA. This is to take into account the self-heating of the sensor caused by excessive current. If KTY84 is used at this time, KTY84 is about 800Ω at 60℃ and the divided voltage output is 2.18V. At 100℃, KTY84 is about 1KΩ and the divided voltage is about 2.63V. At this time, the fifth transistor Q5 is not conducting, the first operational amplifier U28A acts as a follower, the fifty-sixth resistor R56 and the fifty-first capacitor C51 act as a filter, and the second comparator U27B, 1.36V enters the reverse end of the second comparator U27B. As long as the 6th pin of the second comparator U27B is lower than the 5th pin, the second comparator U27B outputs high, which makes the next stage When the third transistor Q3 is turned on, the base of the fourth transistor Q4 will be pulled low and cannot be turned on, then the relay coil RE3 cannot be energized, the contacts will not be attracted, and the fan will not run without power. The 60th resistor R60 is designed to be 20K, and the 78th resistor R78 is designed to be 100K. Because when the voltage of pin 6 of the second comparator U27B is lower than that of pin 5, the output of pin 7 is high, but because pin 7 is directly connected to the third transistor Q3, the direct voltage of pin 7 will be the basic voltage of the transistor 0.6V. The voltage of pin 5 can be calculated to be (2.5-0.6)*resistor R78 / (resistor R78+60th resistor R60)+0.6=2.18V. At this time, the second comparator U27B The output of comparator U27B is reversed and low, the third transistor Q3 is not conducting, and the fourth transistor Q4 is driven to conduct through the sixty-first resistor R61, then the RE3 coil is energized, the contacts are attracted, and the fan is powered to start after the object under test reaches 60℃. At this time, the voltage at pin 5 of the second comparator U27B becomes 2.08V again because pin 7 outputs 0V, which means that when the KTY84 resistance is below 756Ω, the fan stops again. At this time, the temperature corresponding to 756Ω is 50℃, which realizes the hysteresis loop automatic control of turning on at 60℃ and turning off at 50℃, avoiding the fan stopping back and forth at 60℃ when there is no hysteresis loop, affecting the fan life; The second operational amplifier U28B uses the power supply D15V to divide the voltage, and the 5-pin of the second operational amplifier U28B is 1V as the comparison voltage. The second operational amplifier U28B is used as a comparator by connecting the feedback resistor to the non-inverting terminal of the operational amplifier to achieve positive feedback. When KTY84 is short-circuited or below -40℃, the resistance is below 300Ω, that is, when the Temp_S resistor R voltage is less than 0.9V, the follower when the fifth transistor Q5 is not conducting will make the second operational amplifier U28B output high, so that the seventh transistor Q7 is turned on, and then the optocoupler U10 is turned on, and OH outputs a low signal as a fault signal; it is realized that the fault is triggered when the temperature sensor is short-circuited or below -40℃.

[0041] The first comparator U27A is the first comparator, using 2.5V as the comparison voltage, so when the temperature sensor is above 100℃ or the temperature sensor is disconnected, the voltage is between 2.65V and 15V. At this time, it is already greater than 2.5V in the first comparator U27A. The comparator outputs low, making the optocoupler U10 conduct and the OH output low, realizing the alarm when the KTY84 measured temperature is greater than 100℃ or the line is broken. At the same time, the second comparator U27B will also output low, the third transistor Q3 will not conduct, and the fourth transistor Q4 will conduct to close the relay, ensuring that even if the alarm stops due to overtemperature, the fan will continue to run to protect the equipment.

[0042] When the Temp_SR port is used to access PT100, the fifth transistor Q5 will be enabled and turned on. At this time, the first operational amplifier U28A is no longer a follower. When the PT100 temperature is 60℃, the resistance is 125Ω, and the voltage division is 0.388V. The resistor R76=11K, the fifty-sixth resistor R56=51K, and the gain of the first operational amplifier U28A is 5.61. When the PT100 is greater than 60℃, the output of the first operational amplifier U28A will be greater than 2.18V, causing the relay to attract the fan to run. When the temperature drops to 50℃, the corresponding resistance is 118Ω. At this time, the first operational amplifier U28A The output will be less than 2.08V, causing the fan to stop. At this point, the second op amp, U28B, has a comparison voltage of 1V. Therefore, the calculated PT100 resistance must be ≤56Ω for the second op amp, U28B, to output a high value. This is already extremely low temperature, so the comparator circuit here can only detect a short-circuited PT100 fault, which is 0V. The first comparator, U27A, uses 2.5V as the comparison voltage, which calculates the PT100 resistance to be 144Ω, corresponding to 110°C. Therefore, a disconnection or a PT100 temperature ≥110°C will cause the first comparator, U27A, to output a low voltage, turning on the optocoupler and triggering a low OH output. This will also cause the fan drive circuit to operate. Pin header J21 is designed so that if both the op amp and comparator circuits are abnormal, the shorting cap can be shorted to pin 12. This will keep the relay coil energized, allowing the relay contacts to continuously output power and the fan to continue operating, ensuring the device's usability while the control board is replaced.

[0043] The circuit design of the above embodiment achieves compatibility with both KTY84 and PT100 sensors, simplifying the circuit structure and reducing costs and failure risks. Fault detection and emergency response can detect sensor short circuits, open circuits, and overtemperature faults. When a fault occurs, the fan continues to operate and reports the fault, effectively preventing the risk of equipment overheating or fire caused by sensor failure. The above circuit features isolation, ensuring safe detection of sensors installed in live devices. It implements hysteresis-controlled automatic fan control, preventing frequent fan starts and stops at critical temperature points and extending the fan's lifespan. The design of pin header 4 (J21) allows the fan to continue operating manually in the event of an operational amplifier circuit or comparator circuit 2 malfunction, ensuring the device's usability during control board replacement. Overall, this technical solution effectively addresses issues arising from inconsistent temperature sensor types, sensor failures, and live device detection, enabling accurate detection and effective control of device temperature, and improving equipment safety and reliability.

[0044] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A temperature sensor detection circuit with risk control function is used to perform dynamic safety detection on a variety of temperature sensors, characterized in that: The detection circuit comprises: Operational amplifier proportional circuit, comparator circuit and fan drive circuit; The input terminal of the operational amplifier proportional circuit is connected to the third connection terminal of the first operational amplifier, the second connection terminal of the first operational amplifier is grounded, and the first connection terminal of the first operational amplifier is connected to the input terminal of the comparator circuit as the output terminal of the operational amplifier proportional circuit; The input terminal of the comparator circuit is connected to the sixth connection terminal of the second comparator, the fifth connection terminal of the second comparator serves as the input terminal of the comparator circuit, and the seventh connection terminal of the second comparator is connected to an external power supply and to the output terminal of the comparator circuit; The input end of the fan drive circuit is connected to the output end of the comparator circuit, the input end of the comparator circuit is connected to the base of the third transistor, the collector of the third transistor is connected to the base of the fourth transistor, and the emitter of the third transistor is connected to the emitter of the fourth transistor and is grounded; The emitter of the fourth transistor is connected to the first connection end of the pin row, and the second connection end of the pin row is connected to the collector of the fourth transistor.

2. The temperature sensor detection circuit with risk control function according to claim 1, characterized in that: The operational amplifier proportional circuit includes a sixth transistor and a fifty-first capacitor, the base of the sixth transistor is connected to the input power supply, the emitter of the sixth transistor is grounded, the collector of the sixth transistor is connected to the second connection terminal of the first operational amplifier, the fifty-first capacitor is connected to the first operational amplifier in parallel, one end of the fifty-first capacitor is connected to the collector of the sixth transistor, and the other end is connected to the first connection terminal of the first operational amplifier.

3. The temperature sensor detection circuit with risk control function according to claim 2, characterized in that: The detection circuit also includes a reference circuit, which includes a fourth voltage-stabilizing diode, a sixty-second capacitor and a sixty-fourth capacitor. The positive electrode of the fourth voltage-stabilizing diode is grounded, and the negative electrode of the fourth voltage-stabilizing diode is connected to the comparator circuit through the power supply connection terminal. The sixty-second capacitor and the sixty-fourth capacitor are connected in parallel with the fourth voltage-stabilizing diode.

4. The temperature sensor detection circuit with risk control function according to claim 3, characterized in that: The detection circuit also includes an optocoupler circuit, which includes an optocoupler, a sixty-fifth resistor and a sixty-sixth resistor. The first connection end of the optocoupler is connected to the power supply connection end through the sixty-fifth resistor, the second connection end of the optocoupler is connected to the first connection end of the operational amplifier, the sixty-sixth resistor is connected in parallel with the sixty-fifth resistor, one end of the sixty-sixth resistor is connected to the first end of the operational amplifier, the third connection end of the optocoupler is grounded, and the fourth connection end of the optocoupler is grounded.

5. The temperature sensor detection circuit with risk control function according to claim 4, characterized in that: The fan drive circuit includes a fan drive module, the base of the third transistor is connected to the output end of the comparator circuit, the collector of the third transistor is connected to the base of the fourth transistor, the emitter of the third transistor is connected to the pin header and grounded, the collector of the fourth transistor is connected to the fan drive module, and the emitter of the fourth transistor is connected to the pin header and grounded.

6. The temperature sensor detection circuit with risk control function according to claim 3, characterized in that: The voltage threshold of the power supply connection terminal to which the reference circuit is connected is set to 15V.

7. The temperature sensor detection circuit with risk control function according to claim 5, characterized in that: The comparator circuit also includes a first comparator and a second operational amplifier, the positive electrode of the first comparator is grounded, the negative electrode of the first comparator is connected to the power supply connection terminal, the second connection terminal of the first comparator is connected to the output terminal of the operational amplifier proportional circuit, the third connection terminal of the first comparator is connected to an external power supply, the seventh connection terminal of the second operational amplifier is connected to the base of the seventh transistor, the collector of the seventh transistor is connected to the second connection terminal of the optocoupler, and the fifth connection terminal of the second operational amplifier is connected to the power supply connection terminal.

8. The temperature sensor detection circuit with risk control function according to claim 7, characterized in that: The fan drive circuit further includes an eighty-second diode, the anode of the eighty-second diode is connected to the collector of the fourth transistor, and the cathode of the eighty-second diode is connected to the fan drive module.

9. The temperature sensor detection circuit with risk control function according to claim 1, characterized in that: The comparator circuit further includes a fifty-third capacitor, one end of the fifty-third capacitor is connected to the fifth connection end of the second comparator, and the other end of the fifty-third capacitor is grounded.

10. A method for controlling a temperature sensor detection circuit with a risk control function, characterized in that: The control method is applied to the temperature sensor detection circuit with risk control function according to any one of claims 1 to 9, and the control method includes: The operational amplifier proportional circuit generates a control electrical signal through the first operational amplifier included therein, and outputs the control electrical signal to the fan drive circuit through the comparator circuit to perform fan drive control; The comparator circuit performs electrical signal comparison control processing and electrical signal output according to the control electrical signal; The fan driving circuit performs fan driving control according to the control electrical signal after comparison and control processing by the comparator circuit.

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