A detection circuit, a PCB board and a contact type cable temperature measuring device

Abstract

The utility model discloses a kind of detection circuit, PCB board and contact type cable temperature measuring device, detection circuit includes control unit, charging unit, voltage stabilizing filter unit and temperature measuring unit, the input end of charging unit is used to connect external power supply device, the output end of charging unit is connected with the input end of voltage stabilizing filter unit, the output end of voltage stabilizing filter unit is connected with the power supply end of control unit and the power supply end of temperature measuring unit respectively, temperature measuring unit is used to obtain real-time temperature information, the output end of temperature measuring unit is connected with the input end of control unit;The detection circuit disclosed in the application, by configuring voltage stabilizing filter unit, realize multistage noise filtering and voltage stabilization treatment to input power supply, can effectively inhibit the common mode or differential mode interference generated under high electromagnetic environment, avoid the sensor signal drift caused by power fluctuation, ensure the power supply stability of control unit and temperature measuring unit;Meanwhile, power ripple can reduce the work interference of temperature measuring unit, improve measurement accuracy.

Description

Technical Field

[0001] This utility model relates to the field of power equipment condition monitoring technology, and in particular to a detection circuit, PCB board and contact cable temperature measuring device. Background Technology

[0002] As a core component for power transmission, the operating temperature of cables directly reflects the health status of the equipment. During long-term operation, cables are prone to abnormal temperature rise due to factors such as excessive load, poor joint contact, and insulation aging. If not monitored in time, this may lead to serious accidents such as short circuits and fires.

[0003] Current cable temperature measurement technologies include two categories: non-contact and contact technologies. Contact technologies, represented by thermocouples, resistance temperature detectors (RTDs), and semiconductor temperature sensors, acquire temperature signals through direct contact with the object being measured, offering advantages such as high measurement accuracy and good stability. However, existing contact temperature measurement solutions have some limitations in practical applications. Specifically, existing contact temperature measurement solutions lack effective anti-interference design. When the cable is in an environment with high electromagnetic interference, the sensor signal may be affected, leading to drift in the measurement results. Furthermore, in environments with drastic temperature and humidity changes, the material properties of the sensor may be affected, thus impacting measurement accuracy and potentially causing system failure.

[0004] It is evident that existing technologies still need improvement and enhancement. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a detection circuit.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A detection circuit includes a control unit, a charging unit, a voltage stabilizing and filtering unit, and a temperature measuring unit. The input terminal of the charging unit is used to connect to an external power supply device, and the output terminal of the charging unit is connected to the input terminal of the voltage stabilizing and filtering unit. The output terminal of the voltage stabilizing and filtering unit is connected to the power supply terminals of the control unit and the temperature measuring unit, respectively. The temperature measuring unit is used to acquire real-time temperature information, and the output terminal of the temperature measuring unit is connected to the input terminal of the control unit.

[0008] In the detection circuit, the charging unit includes a battery interface J3, the voltage regulation and filtering unit includes a step-down section, a voltage regulator section, and a filter section. The input terminal of the step-down section is connected to the battery interface J3, the output terminal of the step-down section is connected to the input terminals of the filter section, the voltage regulator section, and the power supply terminal of the control unit, respectively, and the output terminal of the voltage regulator section is connected to the power supply terminal of the temperature measuring unit.

[0009] In the detection circuit, the control unit includes a first control chip U1, a crystal oscillator, and a reset unit. The output terminal of the voltage regulation and filtering unit is connected to the VDD pin of the first control chip U1, the crystal oscillator is connected to the OSC pin of the first control chip U1, and the reset unit is connected to the NRST pin of the first control chip U1.

[0010] In the detection circuit, the control unit further includes a display interface and a programming interface. The power supply terminals of the display interface and the programming interface are respectively connected to the output terminal of the voltage regulation and filtering unit. The display interface is connected to pins SCL and SCA of the first control chip U1, and the programming interface is connected to pins PA13 and PA14 of the first control chip U1.

[0011] In the detection circuit, the charging unit further includes a charging interface section and a charging management section. The input end of the charging interface section is used to connect to an external power supply device. The output end of the charging interface section is connected to the input end of the charging management section. The output end of the charging management section is connected to the battery interface J3. The battery interface J3 is used to connect to a lithium battery.

[0012] In the detection circuit, the charging unit further includes a power detection unit. The input terminal of the power detection unit is connected to the battery interface J3, and the output terminal of the power detection unit is connected to pin PB0 of the first control chip U1.

[0013] In the detection circuit, the charging unit further includes an indicator, the power supply terminal of which is connected to the output terminal of the voltage stabilizing and filtering unit, and the input terminal of which is connected to pin PA6 and pin PA7 of the first control chip U1, respectively.

[0014] In the detection circuit, the temperature measurement unit includes a temperature monitoring unit and an alarm unit. The power supply terminals of the temperature monitoring unit and the alarm unit are respectively connected to the output terminal of the voltage regulation and filtering unit. The output terminal of the temperature monitoring unit is connected to pin PB1 of the first control chip U1, and the input terminal of the alarm unit is connected to pin PA8 of the first control chip U1.

[0015] This utility model also provides a PCB board, on which the detection circuits described above are printed.

[0016] This utility model also provides a contact cable temperature measuring device, including a housing, in which a PCB board as described above is disposed, and a temperature measuring resistor, a display screen, an alarm device, an indicator device and a charging interface are disposed on the housing and electrically connected to the PCB board respectively.

[0017] Beneficial effects:

[0018] This invention provides a detection circuit that, by configuring a voltage regulator and filter unit, achieves multi-stage noise filtering and voltage stabilization of the input power supply. This effectively suppresses common-mode or differential-mode interference generated under high electromagnetic environments, avoids sensor signal drift caused by power fluctuations, and ensures the power supply stability of the control unit and temperature measurement unit. At the same time, it can reduce the interference of power supply ripple on the operation of the temperature measurement unit and improve the measurement accuracy of the temperature measurement unit. Attached Figure Description

[0019] Figure 1 A circuit block diagram of the detection circuit provided by this utility model;

[0020] Figure 2 A circuit diagram of the control unit provided by this utility model;

[0021] Figure 3 A circuit diagram of the charging unit provided by this utility model;

[0022] Figure 4 Circuit structure diagram of the voltage stabilizing filter unit provided by this utility model;

[0023] Figure 5 The circuit structure diagram of the temperature measuring unit provided by this utility model.

[0024] Explanation of main component symbols: 1-Control unit, 11-Crystal oscillator, 12-Reset unit, 13-Display interface unit, 14-Programming interface unit, 2-Charging unit, 21-Charging interface unit, 22-Charging management unit, 23-Power detection unit, 24-Indicator unit, 3-Voltage stabilization and filtering unit, 31-Step-down unit, 32-Voltage stabilization unit, 33-Filtering unit, 4-Temperature measurement unit, 41-Temperature monitoring unit, 42-Alarm unit. Detailed Implementation

[0025] This utility model provides a detection circuit, PCB board, and contact cable temperature measuring device. To make the purpose, technical solution, and effects of this utility model clearer and more explicit, the following describes this utility model in further detail with reference to the accompanying drawings and embodiments.

[0026] In the description of this utility model, it should be understood that the terms "installation" and "connection" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] Please see Figures 1 to 5This utility model provides a detection circuit, including a control unit 1, a charging unit 2, a voltage stabilizing and filtering unit 3, and a temperature measuring unit 4. The input terminal of the charging unit 2 is used to connect to an external power supply device, and the output terminal of the charging unit 2 is connected to the input terminal of the voltage stabilizing and filtering unit 3. The output terminal of the voltage stabilizing and filtering unit 3 is connected to the power supply terminals of the control unit 1 and the temperature measuring unit 4, respectively. The temperature measuring unit 4 is used to acquire real-time temperature information, and the output terminal of the temperature measuring unit 4 is connected to the input terminal of the control unit 1.

[0028] This invention provides a detection circuit that, by configuring a voltage stabilizing filter unit 3, achieves multi-stage noise filtering and voltage stabilization of the input power supply. This effectively suppresses common-mode or differential-mode interference generated under high electromagnetic environments, avoids sensor signal drift caused by power supply fluctuations, and ensures the power supply stability of the control unit 1 and the temperature measuring unit 4. At the same time, it can reduce the interference of power supply ripple on the operation of the temperature measuring unit 4 and improve the measurement accuracy of the temperature measuring unit 4.

[0029] Further, please refer to Figure 1 , Figure 3 and Figure 4 The charging unit 2 includes a battery interface J3, and the voltage regulation and filtering unit 3 includes a step-down section 31, a voltage regulator section 32, and a filter section 33. The input terminal of the step-down section 31 is connected to the battery interface J3, and the output terminal of the step-down section 31 is connected to the input terminals of the filter section 33, the voltage regulator section 32, and the power supply terminal of the control unit 1, respectively. The output terminal of the voltage regulator section 32 is connected to the power supply terminal of the temperature measuring unit 4.

[0030] In this embodiment, please refer to Figure 4 The step-down circuit includes a first trigger button SW1 and a second control chip U2, the second control chip U2 being model SSP7603P33MR. The first trigger button SW1 is a power button located on the housing. The voltage regulator 32 includes a seventh control chip U7, the seventh control chip U7 being model REF3030AIDBZR. The filter 33 is a parallel capacitor bank, the parallel capacitor bank including a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6 connected in parallel. Pin 5 of the first trigger button SW1 is connected to pin 1 of the battery interface J3. Pin 6 of the first trigger button SW1 is connected to pin VIN of the second control chip U2. Pin VOUT of the second control chip U2 is connected to one end of the filter 33 and pin IN of the seventh control chip U7. The other end of the filter 33 is grounded. Pin OUT of the seventh control chip U7 is connected to the power supply terminal of the temperature measuring unit 4.

[0031] In this embodiment, the lithium battery voltage is stepped down to 3.3V by the second control chip U2 to power the first control chip U1 and peripherals of the temperature measuring device, such as the display screen. Under voltage fluctuations, the second control chip U2 can output a fixed 3.3V to ensure power supply stability. It also features low quiescent current, making it suitable for battery-powered scenarios and extending the battery life of the temperature measuring device. The seventh control chip U7 provides a high-precision reference voltage, specifically powering the temperature monitoring unit 41, ensuring the stability of the voltage divider circuit. Furthermore, the seventh control chip U7 has low drift characteristics, effectively avoiding temperature measurement errors caused by power fluctuations, especially during long-term monitoring. The parallel capacitor bank employs a multi-stage filtering method to effectively suppress electromagnetic interference in the power environment, such as high-frequency noise near cables, ensuring the purity of the analog signal. The analog information includes temperature and voltage, thus improving temperature detection accuracy.

[0032] Further, please refer to Figure 1 and Figure 2 The control unit 1 includes a first control chip U1, a crystal oscillator 11, and a reset unit 12. The output terminal of the voltage regulation and filtering unit 3 is connected to the VDD pin of the first control chip U1, the crystal oscillator 11 is connected to the OSC pin of the first control chip U1, and the reset unit 12 is connected to the NRST pin of the first control chip U1.

[0033] In this embodiment, please refer to Figure 2 The first control chip U1 is an STM32L051C8T6. The crystal oscillator section 11 includes a crystal oscillator X1, and the reset section 12 includes a reset switch RST1. The two ends of the crystal oscillator X1 are respectively connected to the OSC pin of the first control chip U1. One end of the reset switch RST1 is connected to the NRST pin of the first control chip U1, and the other end of the first control chip U1 is grounded.

[0034] In this embodiment, the first control chip U1, model STM32L051C8T6, has a current as low as 1.6μA in standby mode, making it suitable for long-term offline monitoring. It also has a built-in ADC and communication interface, which can effectively reduce the number of external chips, shrink the PCB size, and greatly reduce the production cost of the temperature measuring device. The control unit 1 is equipped with a 16MHz crystal oscillator 11 and a hardware reset circuit to ensure that the ADC sampling clock accuracy reaches ±0.5%, thus ensuring the accuracy of temperature data from the hardware level.

[0035] Further, please refer to Figure 1 and Figure 2The control unit 1 further includes a display interface section 13 and a programming interface section 14. The power supply terminals of the display interface section 13 and the programming interface section 14 are respectively connected to the output terminal of the voltage regulation and filtering unit 3. The display interface section 13 is connected to pins SCL and SCA of the first control chip U1, and the programming interface section 14 is connected to pins PA13 and PA14 of the first control chip U1.

[0036] In this embodiment, please refer to Figure 2 The programming interface section 14 includes a first connector J1, and pins 3 and 2 of the first connector J1 are respectively connected to pins PA13 and PA14 of the first control chip U1; the display interface section 13 includes a second connector J2, and pins 3 and 4 of the second connector J2 are respectively connected to pins SCL and SCA of the first control chip U1.

[0037] In this embodiment, the display interface 13 is used to connect to the I2C display screen to display data such as temperature and power in real time. The programming interface 14 supports the SWD debugging protocol, which facilitates program download and firmware upgrade. The display interface 13 and the programming interface 14 adopt independent power supply paths and are connected to the first control chip U1 through dedicated pins such as SCL / SCA and PA13 / PA14 to form physical isolation of signal transmission and reduce crosstalk of digital circuits to analog temperature measurement signals.

[0038] Further, please refer to Figure 1 and Figure 3 The charging unit 2 further includes a charging interface section 21 and a charging management section 22. The input end of the charging interface section 21 is used to connect to an external power supply device. The output end of the charging interface section 21 is connected to the input end of the charging management section 22. The output end of the charging management section 22 is connected to the battery interface J3. The battery interface J3 is used to connect to a lithium battery.

[0039] In this embodiment, please refer to Figure 3 The charging interface unit 21 includes an interface chip USB1, the model of which is TYPE-C 6P; the charging management unit 22 includes a third control chip U3, the model of which is TP4056_C725790; pin A9 of the interface chip USB1 is used to connect to an external power supply device, which can be a 5V USB adapter; pin B9 of the interface chip USB1 is connected to pin VCC of the third control chip U3, and pin BAT+ of the third control chip U3 is connected to pin 1 of the battery interface J3.

[0040] In this embodiment, the third control chip U3 is used as the charging management core. The TP4056 has built-in overcharge, overcurrent and overheat protection mechanisms to prevent the battery from exploding or having its lifespan reduced due to abnormal charging. The external power supply is connected through the USB1 interface. The charging unit 2 is compatible with the mainstream USB-C interface and supports 5V power input. It has the advantage of strong adaptability and is convenient for on-site charging of portable temperature measuring devices.

[0041] Further, please refer to Figure 1 and Figure 3 The charging unit 2 further includes a power detection unit 23, the input terminal of which is connected to the battery interface J3, and the output terminal of which is connected to the pin PB0 of the first control chip U1.

[0042] In this embodiment, the power detection unit 23 includes a first resistor R1 and a third resistor R3. One end of the first resistor R1 is connected to pin 1 of the battery interface J3, and the other end of the first resistor R1 and one end of the third resistor R3 are respectively connected to pin PB0 of the first control chip U1. The other end of the third resistor R3 is grounded.

[0043] In this embodiment, pin 1 of battery interface J3 is connected to a lithium battery. The lithium battery voltage is divided by the first resistor R1 and the third resistor R3 and then input to the first control chip U1. The first control chip U1 can map the voltage value to the power percentage to realize low power warning. When the power is lower than the preset voltage threshold, the first control chip U1 can control the power supply of non-core modules to be cut off, thereby extending the service life of the lithium battery.

[0044] Further, please refer to Figure 1 and Figure 3 The charging unit 2 further includes an indicator 24, the power supply terminal of which is connected to the output terminal of the voltage regulation and filtering unit 3, and the input terminal of which is connected to pin PA6 and pin PA7 of the first control chip U1, respectively.

[0045] In this embodiment, the indicator 24 can be used to provide feedback on the working status of the temperature measuring device, the charging progress, or to provide a low battery warning, which can effectively improve the user experience.

[0046] In this embodiment, please refer to Figure 3 The indicator unit 24 includes a tenth resistor R10 and an indicator light U9. One end of the tenth resistor R10 is connected to the output terminal of the step-down unit 31, and the other end of the tenth resistor R10, as well as pins PA6 and PA7 of the first control chip U1, are respectively connected to the indicator light U9.

[0047] Further, please refer to Figure 1 and Figure 5 The temperature measuring unit 4 includes a temperature monitoring unit 41 and an alarm unit 42. The power supply terminals of the temperature monitoring unit 41 and the alarm unit 42 are respectively connected to the output terminal of the voltage stabilizing and filtering unit 3. The output terminal of the temperature monitoring unit 41 is connected to pin PB1 of the first control chip U1, and the input terminal of the alarm unit 42 is connected to pin PA8 of the first control chip U1.

[0048] In this embodiment, please refer to Figure 5 The temperature monitoring unit 41 includes a seventh resistor R7, a temperature sensing resistor R8, and a fourteenth capacitor C14. The alarm unit 42 includes an eleventh resistor R11, a first transistor Q1, and a buzzer B1. One end of the seventh resistor R7 is connected to the output terminal of the voltage regulator unit 32. The other end of the seventh resistor R7 is connected to one end of the fourteenth capacitor C14, one end of the temperature sensing resistor R8, and pin PB1 of the first control chip U1. The other ends of the fourteenth capacitor C14 and the temperature sensing resistor R8 are grounded. One end of the eleventh resistor R11 is connected to pin PA8 of the first control chip U1. The other end of the eleventh resistor R11 is connected to the base of the first transistor Q1. The collector of the first transistor Q1 is connected to pin 2 of the buzzer B1. Pin 1 of the buzzer B1 is connected to the output terminal of the step-down unit 31. The emitter of the first transistor Q1 is grounded.

[0049] In this embodiment, the temperature sensing resistor R8 is an MF52 negative temperature coefficient thermistor. The temperature sensing resistor R8 and the seventh resistor R7 form a voltage divider circuit, which inputs the real-time temperature signal to pin PB1 of the first control chip U1. Pin PB1 of the first control chip U1 is an ADC channel. The nonlinear characteristics of the thermistor are compensated by a lookup table through the built-in algorithm of the first control chip U1, thereby improving the accuracy of measurement across the entire temperature range. The fourteenth capacitor C14 is connected in parallel at the voltage divider output terminal to filter out high-frequency noise and ensure the stability of the temperature and voltage signals.

[0050] In this embodiment, the first transistor Q1 acts as a switch, controlled by pin PA8 of the first control chip U1, driving the buzzer B1 to sound. The eleventh resistor R11 is the base current limiting resistor, ensuring that the first transistor Q1 is reliably turned on or off. When the measured temperature exceeds the preset temperature threshold, the buzzer B1 is triggered within 100ms, allowing on-site personnel to quickly locate the overheated area and provide timely warning and intervention. When the measured temperature is less than the preset temperature threshold, the buzzer B1 does not work, and the temperature measuring device is in a low-power standby state, which does not affect the battery life.

[0051] This utility model also provides a PCB board, on which the detection circuits described above are printed.

[0052] This utility model also provides a contact cable temperature measuring device, including a housing, in which a PCB board as described above is disposed, and a temperature measuring resistor, a display screen, an alarm device, an indicator device and a charging interface are disposed on the housing and electrically connected to the PCB board respectively.

[0053] In this embodiment, the housing includes a main body and a rear cover. The PCB board is disposed within the main body, and the display screen is disposed in the middle of the rear cover and electrically connected to the PCB board. The charging interface and the indicator device are respectively disposed on the top of the main body, and the indicator device is an indicator light. The temperature measuring resistor is disposed on the front side of the main body, and the alarm device is disposed on the bottom of the main body, and the alarm device is a buzzer. A power button electrically connected to the PCB board is also disposed on the side of the housing.

[0054] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this utility model, and all such substitutions or changes should fall within the protection scope of this utility model.

Claims

1. A detection circuit, characterized in that, The device includes a control unit, a charging unit, a voltage stabilizing and filtering unit, and a temperature measuring unit. The input terminal of the charging unit is used to connect to an external power supply device, and the output terminal of the charging unit is connected to the input terminal of the voltage stabilizing and filtering unit. The output terminal of the voltage stabilizing and filtering unit is connected to the power supply terminals of the control unit and the temperature measuring unit, respectively. The temperature measuring unit is used to acquire real-time temperature information, and the output terminal of the temperature measuring unit is connected to the input terminal of the control unit.

2. The detection circuit according to claim 1, characterized in that, The charging unit includes a battery interface J3, and the voltage regulation and filtering unit includes a step-down section, a voltage regulator section, and a filter section. The input terminal of the step-down section is connected to the battery interface J3, and the output terminal of the step-down section is connected to the input terminals of the filter section, the voltage regulator section, and the power supply terminal of the control unit. The output terminal of the voltage regulator section is connected to the power supply terminal of the temperature measuring unit.

3. The detection circuit according to claim 2, characterized in that, The control unit includes a first control chip U1, a crystal oscillator, and a reset unit. The output terminal of the voltage regulation and filtering unit is connected to the VDD pin of the first control chip U1, the crystal oscillator is connected to the OSC pin of the first control chip U1, and the reset unit is connected to the NRST pin of the first control chip U1.

4. The detection circuit according to claim 3, characterized in that, The control unit further includes a display interface and a programming interface. The power supply terminals of the display interface and the programming interface are respectively connected to the output terminal of the voltage regulation and filtering unit. The display interface is connected to pins SCL and SCA of the first control chip U1, and the programming interface is connected to pins PA13 and PA14 of the first control chip U1.

5. A detection circuit according to claim 4, characterized in that, The charging unit further includes a charging interface section and a charging management section. The input end of the charging interface section is used to connect to an external power supply device. The output end of the charging interface section is connected to the input end of the charging management section. The output end of the charging management section is connected to the battery interface J3. The battery interface J3 is used to connect to a lithium battery.

6. A detection circuit according to claim 5, characterized in that, The charging unit also includes a power detection unit, the input end of which is connected to the battery interface J3, and the output end of which is connected to pin PB0 of the first control chip U1.

7. A detection circuit according to claim 6, characterized in that, The charging unit also includes an indicator, the power supply terminal of which is connected to the output terminal of the voltage regulator and filter unit, and the input terminal of which is connected to pin PA6 and pin PA7 of the first control chip U1, respectively.

8. A detection circuit according to claim 4, characterized in that, The temperature measurement unit includes a temperature monitoring unit and an alarm unit. The power supply terminals of the temperature monitoring unit and the alarm unit are respectively connected to the output terminal of the voltage regulation and filtering unit. The output terminal of the temperature monitoring unit is connected to pin PB1 of the first control chip U1, and the input terminal of the alarm unit is connected to pin PA8 of the first control chip U1.

9. A PCB board, characterized in that, The PCB board is printed with the detection circuit as described in any one of claims 1-8.

10. A contact-type cable temperature measuring device, comprising a housing, characterized in that, The housing contains a PCB board as described in claim 9, and the housing is provided with a temperature measuring resistor, a display screen, an alarm device, an indicator device, and a charging interface, which are respectively electrically connected to the PCB board.

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