Protection circuit

Abstract

The utility model discloses a protection circuit. The protection circuit comprises a sampling module, a threshold comparison module and an alarm module which are connected. The sampling module is used for sampling the current of the loop to be monitored to obtain a real-time sampling signal; the threshold comparison module is used for comparing the sampling signal acquired by the sampling module with a preset threshold and outputting a high-level signal to the alarm module when the sampling signal exceeds the preset threshold; the alarm module is used for sending an alarm signal according to the high-level signal. According to the utility model, accurate sampling and timely protection of current can be realized.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit protection technology, and in particular to a protection circuit. Background Technology

[0002] In modern electronic devices, existing current protection circuits mainly suffer from the following problems: Traditional current protection circuits use a single sampling method, which is easily affected by external interference, resulting in insufficient sampling accuracy. Furthermore, due to the signal transmission delay between the sampling circuit and the detection circuit, the protection mechanism cannot be triggered in a timely manner when an overcurrent fault occurs, increasing the risk of equipment damage.

[0003] Furthermore, in existing technologies, sampling, monitoring, and alarm circuits are typically designed separately, resulting in poor coordination between modules. This not only increases circuit complexity but also reduces the reliability of the overall protection system. This decentralized design leads to large circuit layout area, high cost, and hinders the development of product integration.

[0004] Therefore, it is urgent to propose a protection circuit to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to propose a protection circuit that can achieve accurate current sampling and timely protection.

[0006] To solve the above-mentioned technical problems, this utility model provides a protection circuit, including a sampling module, a threshold comparison module and an alarm module connected in series;

[0007] The sampling module is used to sample the current of the circuit to be monitored and obtain the real-time sampling signal.

[0008] The threshold comparison module is used to compare the sampled signal acquired by the sampling module with a preset threshold, and output a high-level signal to the alarm module when the sampled signal exceeds the preset threshold;

[0009] The alarm module is used to issue an alarm signal based on the high-level signal.

[0010] Furthermore, the sampling module includes a sensor, a first inductor with a magnetic core, a second inductor with a magnetic core, a capacitor assembly, and a first resistor;

[0011] The sensor's input terminal is used to connect to the current of the circuit to be monitored, and its output terminal is used to output a sampling signal to the threshold comparison module. The sensor is connected to one end of the capacitor assembly; the sensor's output terminal is grounded through the first resistor.

[0012] The other end of each capacitor assembly is grounded, and a portion of the capacitors in the capacitor assembly are connected to one end of the first inductor with a magnetic core, while the other portion of the capacitors are connected to one end of the second inductor with a magnetic core.

[0013] The other ends of the first magnetic core inductor and the second magnetic core inductor are respectively connected to the positive and negative terminals of the power supply voltage.

[0014] Furthermore, the capacitor assembly includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor;

[0015] One end of the first capacitor, the second capacitor, and the third capacitor is connected to one end of the second inductor with a magnetic core; one end of the fourth capacitor, the fifth capacitor, and the sixth capacitor is connected to one end of the first inductor with a magnetic core; the other ends of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor are all grounded.

[0016] Furthermore, the sensor includes a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin, an eighth pin, and a ninth pin;

[0017] The first pin is connected to the first capacitor, the second capacitor, and the third capacitor;

[0018] The second pin is connected to the fourth capacitor, the fifth capacitor, and the sixth capacitor;

[0019] The third pin is the input terminal of the sensor;

[0020] The sensor's input terminals include a first input terminal and a second input terminal;

[0021] The fourth pin, the fifth pin, and the sixth pin are the first input terminals;

[0022] The seventh pin, the eighth pin, and the ninth pin are the second input terminals.

[0023] Furthermore, the threshold comparison module includes a comparator, a trigger, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a second resistor, a fourth resistor, a fifth resistor, a seventh resistor, an eighth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first Zener diode, and a second Zener diode.

[0024] The comparator is connected to the trigger, the seventh capacitor, the eighth capacitor, the ninth capacitor, the tenth capacitor, the fifth resistor, the seventh resistor, the eighth resistor, the tenth resistor, the eleventh resistor, the thirteenth resistor, the fourteenth resistor, and the first Zener diode;

[0025] The trigger is connected to the eleventh capacitor, the second resistor, the fourth resistor, the twelfth resistor, and the second Zener diode.

[0026] Furthermore, the first pin of the comparator is connected to the negative terminal of the first Zener diode, one end of the ninth capacitor, and one end of the seventh resistor; the second pin is connected to one end of the eighth capacitor, the tenth resistor, and the fifth resistor; the third, fourth, and fifth pins, the other ends of the eighth capacitor and the tenth resistor are grounded; the fifth pin is connected to one end of the seventh capacitor; the seventh pin is connected to the CLK pin of the flip-flop; and the eighth pin is connected to the other end of the seventh capacitor, the power supply voltage, and the other end of the fifth resistor.

[0027] The other end of the seventh resistor is connected to one end of the tenth capacitor and one end of the eighth resistor, and the other end of the seventh resistor is used to receive the sampling signal from the sampling module;

[0028] The other end of the seventh resistor, the eleventh resistor, the thirteenth resistor, and the fourteenth resistor are connected in series.

[0029] The end of the fourteenth resistor furthest from the thirteenth resistor is grounded;

[0030] The positive terminal of the first Zener diode, the other end of the ninth capacitor, and the other end of the tenth capacitor are all grounded.

[0031] Furthermore, the second pin of the trigger is grounded, the third and fifth pins are both connected to the power supply voltage, and the fourth pin is connected to one end of the fourth resistor and the alarm module; the other end of the fourth resistor is connected to the positive terminal of the second Zener diode; the negative terminal of the second Zener diode is connected to the control pin of the driver chip; the driver chip control signal sent by the MCU is first grounded through the second resistor, and then connected to the control pin of the driver chip.

[0032] The sixth pin of the comparator is connected to one end of the twelfth resistor, one end of the eleventh capacitor, and the reset signal; the other end of the twelfth resistor is connected to the power supply voltage; and the other end of the eleventh capacitor is grounded.

[0033] Furthermore, the comparator model includes TLV3502AIDR; ​​the trigger includes SN74LVC1G175DCKR single Schmitt trigger.

[0034] Furthermore, the alarm module includes a logic chip, a light-emitting diode, a third resistor, a sixth resistor, and a ninth resistor;

[0035] The second pin of the logic chip is connected to the threshold comparison module and one end of the third resistor, and the fourth pin is connected to one end of the sixth resistor; the third pin of the logic chip is grounded; the fifth pin of the logic chip is connected to the power supply voltage.

[0036] The positive terminal of the light-emitting diode is connected to the other end of the third resistor, and the negative terminal is grounded;

[0037] The other end of the sixth resistor is grounded through the ninth resistor; the logic chip outputs an alarm signal between the sixth resistor and the ninth resistor.

[0038] Furthermore, the logic chip model includes the SN74AHC1G04DCKR single-gate NOT gate logic chip.

[0039] Through the above technical solution, this utility model has the following beneficial effects:

[0040] By combining the sampling module, threshold comparison module, and alarm module, accurate current sampling, rapid comparison, and timely alarm functions are achieved, thereby improving the circuit's response speed and protection effect.

[0041] In addition, the sampling module uses a sensor combined with a magnetic core inductor and capacitor design, which effectively improves the sampling accuracy and anti-interference capability.

[0042] In addition, the threshold comparison module adopts a combination design of comparator and flip-flop, and improves the accuracy and reliability of comparison through multi-level resistor voltage division and Zener diode protection; and the alarm module is controlled by logic chip and displayed with light-emitting diode, realizing the output of multiple alarm modes, enhancing the practicality and ease of operation of the circuit. Attached Figure Description

[0043] Figure 1 This is a block diagram of the protection circuit in one embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the sampling module in the protection circuit of one embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the threshold comparison module and alarm module in the protection circuit of one embodiment of the present invention.

[0046] U1, sensor; R1, first resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; C5, fifth capacitor; C6, sixth capacitor; L1, first inductor with magnetic core; L2, second inductor with magnetic core;

[0047] U2, Comparator; U3, Flip-flop; C7, Seventh capacitor; C8, Eighth capacitor; C9, Ninth capacitor; C10, Tenth capacitor; C11, Eleventh capacitor; R2, Second resistor; R4, Fourth resistor; R5, Fifth resistor; R7, Seventh resistor; R8, Eighth resistor; R10, Tenth resistor; R11, Eleventh resistor; R12, Twelfth resistor; R13, Thirteenth resistor; R14, Fourteenth resistor; D1, First Zener diode; D2, Second Zener diode;

[0048] U4, logic chip; D3, light-emitting diode; R3, third resistor; R6, sixth resistor; R9, ninth resistor. Detailed Implementation

[0049] The following description, in conjunction with the accompanying drawings, provides a more detailed view of a protection circuit according to the present invention, illustrating preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the scope of the invention.

[0050] The present invention will be described in more detail below by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0051] like Figure 1 As shown in the figure, this utility model embodiment proposes a protection circuit, including a sampling module, a threshold comparison module and an alarm module connected together.

[0052] Specifically, the sampling module is used to sample the current of the circuit to be monitored and obtain a real-time sampling signal; the threshold comparison module is used to compare the sampling signal obtained by the sampling module with a preset threshold, and when the sampling signal exceeds the preset threshold, outputs a high-level signal to the alarm module; the alarm module is used to issue an alarm signal based on the high-level signal. This embodiment, through the cooperation of the sampling module, threshold comparison module, and alarm module, can improve the overall response speed of the circuit and enhance the timeliness of protection.

[0053] In a specific example, such as Figure 2 As shown, the sampling module includes a sensor U1, a first magnetic core inductor L1, a second magnetic core inductor L2, a capacitor assembly, and a first resistor R1. The sensor U1 can be an LAX100-NP sensor; as those skilled in the art will know, the sensor U1 model can be set according to actual needs.

[0054] Specifically, the input terminal of the sensor U1 is used to connect the current of the circuit to be monitored (i.e., as shown in the image). Figure 2 The current (from J1 or J2) is used to output a sampling signal to the threshold comparison module. The sensor U1 is connected to one end of the capacitor assembly; the output of the sensor U1 is grounded through the first resistor R1; the other end of the capacitor assembly is grounded, and a portion of the capacitors in the capacitor assembly are connected to one end of the first magnetic core inductor L1, and another portion of the capacitors are connected to one end of the second magnetic core inductor L2; the other ends of the first magnetic core inductor L1 and the second magnetic core inductor L2 are respectively connected to the positive and negative terminals of the power supply voltage. This embodiment, through the combination of the above structures, can enhance the stability and anti-interference capability of the sampling signal.

[0055] The sampling signal includes a current value, which is converted into a measurable voltage or current signal by sensor U1. This signal is then compared by a threshold comparison module, which outputs the result. When the current value exceeds a preset threshold, the comparison module outputs a high-level signal and automatically locks the drive signal. The alarm module issues an alarm signal when the threshold comparison module outputs a high-level signal, prompting the user to take protective measures.

[0056] In this embodiment, the capacitor assembly includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6.

[0057] Specifically, one end of the first capacitor C1, the second capacitor C2, and the third capacitor C3 is connected to one end of the second inductor L2 with a magnetic core; one end of the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 is connected to one end of the first inductor L1 with a magnetic core; the other ends of the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are all grounded. Those skilled in the art will know that the capacitance values ​​can be set according to actual needs.

[0058] In this embodiment, the sensor U1 includes a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin, an eighth pin, and a ninth pin.

[0059] Specifically, the first pin is connected to the first capacitor C1, the second capacitor C2, and the third capacitor C3; the second pin is connected to the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6; the third pin is the input terminal of the sensor U1; the input terminals of the sensor U1 include a first input terminal and a second input terminal; the fourth, fifth, and sixth pins are the first input terminals; and the seventh, eighth, and ninth pins are the second input terminals. This embodiment can enhance the accuracy of signal acquisition.

[0060] In a specific example, such as Figure 3 As shown, the threshold comparison module includes a comparator U2, a trigger U3, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a second resistor R2, a fourth resistor R4, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a first Zener diode D1, and a second Zener diode D2.

[0061] Specifically, the comparator U2 is connected to the trigger U3, the seventh capacitor C7, the eighth capacitor C8, the ninth capacitor C9, the tenth capacitor C10, the fifth resistor R5, the seventh resistor R7, the eighth resistor R8, the tenth resistor R10, the eleventh resistor R11, the thirteenth resistor R13, the fourteenth resistor R14, and the first Zener diode D1; the trigger U3 is connected to the eleventh capacitor C11, the second resistor R2, the fourth resistor R4, the twelfth resistor R12, and the second Zener diode D2.

[0062] Furthermore, the first pin of the comparator U2 is connected to the negative terminal of the first Zener diode D1, one end of the ninth capacitor C9, and one end of the seventh resistor R7; the second pin is connected to one end of the eighth capacitor C8, the tenth resistor R10, and the fifth resistor R5; the third, fourth, and fifth pins, the other end of the eighth capacitor C8, and the tenth resistor R10 are grounded; the fifth pin is connected to one end of the seventh capacitor C7; the seventh pin is connected to the CLK pin of the flip-flop U3; and the eighth pin is connected to the other end of the seventh capacitor C7, the power supply voltage, and the... The other end of the fifth resistor R5; the other end of the seventh resistor R7 is connected to one end of the tenth capacitor C10 and the eighth resistor R8, and the other end of the seventh resistor R7 is used to receive the sampling signal from the sampling module; the other end of the seventh resistor R7, the eleventh resistor R11, the thirteenth resistor R13 and the fourteenth resistor R14 are connected in series; the end of the fourteenth resistor R14 away from the thirteenth resistor R13 is grounded; the positive terminal of the first Zener diode D1, the other end of the ninth capacitor C9 and the other end of the tenth capacitor C10 are all grounded.

[0063] Furthermore, the second pin of the trigger U3 is grounded, the third and fifth pins are both connected to the power supply voltage, and the fourth pin is connected to one end of the fourth resistor R4 and the alarm module; the other end of the fourth resistor R4 is connected to the positive terminal of the second Zener diode D2; the negative terminal of the second Zener diode D2 is connected to the control pin of the driver chip; the driver chip control signal issued by the MCU is first grounded through the second resistor R2, and then connected to the control pin of the driver chip; the sixth pin of the comparator U2 is connected to one end of the twelfth resistor R12, one end of the eleventh capacitor C11, and the reset signal; the other end of the twelfth resistor R12 is connected to the power supply voltage; the other end of the eleventh capacitor C11 is grounded.

[0064] Preferably, the comparator U2 is a TLV3502AIDR; ​​the trigger U3 is a SN74LVC1G175DCKR single Schmitt trigger. Those skilled in the art will know that other chip models can be selected according to actual needs.

[0065] In one embodiment, the connection of the first to eighth pins of the comparator U2 to each component improves the accuracy and stability of signal comparison. When the input signal exceeds a preset threshold, the comparator U2 outputs a high-level trigger signal, which is processed by the trigger U3 and then output to the alarm module, achieving fast and accurate threshold judgment.

[0066] In a specific example, continue to refer to Figure 3As shown, the alarm module includes a logic chip U4, a light-emitting diode D3, a third resistor R3, a sixth resistor R6, and a ninth resistor R9.

[0067] Specifically, the second pin (i.e., the input terminal) of the logic chip U4 is connected to the threshold comparison module and one end of the third resistor R3, and the fourth pin (i.e., the output terminal) is connected to one end of the sixth resistor R6; the third pin of the logic chip U4 is grounded; the fifth pin of the logic chip U4 is connected to the power supply voltage; the positive terminal of the light-emitting diode D3 is connected to the other end of the third resistor R3, and the negative terminal is grounded; the other end of the sixth resistor R6 is grounded through the ninth resistor R9; the logic chip U4 outputs an alarm signal through the connection between the sixth resistor R6 and the ninth resistor R9. This embodiment, through the combination of the above structures, can enhance the reliability of the alarm signal.

[0068] Furthermore, the logic chip U4 includes the SN74AHC1G04DCKR single-gate NOT gate logic chip. Those skilled in the art will understand that other chip models can be selected based on actual needs.

[0069] In one specific embodiment, the result of the comparison between the current sampling module and the threshold comparison module serves as a control signal for trigger U3. The reset signal for trigger U3 can be provided by an external control signal, and the output signal of trigger U3 serves as the alarm light status and the input signal for logic chip U4. Logic chip U4 issues an alarm signal based on the output signal of trigger U3 for users to perform customized alarm processing.

[0070] Pulling the pin of LED D3 and the resistor in series high will trigger an alarm; normally, it will be at a low level. This pin (i.e., pin A) will then trigger an alarm. Figure 3 The logic chip U4 operates normally when pin A is low. Therefore, when pin A is low, the Q pin output of flip-flop U3 is low. The truth table of flip-flop U3 is shown in Table 1 below:

[0071] Table 1

[0072]

[0073] In Table 1, H represents high level, L represents low level, ↑ represents rising edge, X represents any level (does not affect output), and Q0 represents maintaining the original state.

[0074] like Figure 3 The middle D pin (i.e. Figure 3 The third pin of the flip-flop U3 and the reset pin (i.e. Figure 3 The sixth pin of the trigger U3 or CLRWhen all pins (i.e., Q, Q, Q) are connected to a high level, the CLK pin is used to compare the set current value (i.e., the preset threshold) with the sampled current value (i.e., the sampling signal). If the sampled current value exceeds the set current value, a high-level signal is output. Figure 3 The fourth pin of the trigger U3 outputs a high level, and through the fourth resistor R4 and the second Zener diode D2, it pulls the control pin of the driver chip high to achieve a latching drive signal for rapid shutdown. Pin A is high for alarm. Fault reset only requires... CLR A positive pulse is sufficient to power the pin (i.e., the reset pin).

[0075] In practical applications, parameters need to be adjusted according to the specific requirements of the circuit, such as the size of the sampling resistor and the threshold voltage of comparator U2. Furthermore, the circuit needs to be tested and verified to ensure reliable operation under various conditions. Through the above design, this protection circuit can effectively monitor the circuit status and respond promptly when abnormal signals are detected, thereby protecting electronic equipment from damage.

[0076] In this embodiment, the current of the circuit to be monitored is first sampled through the input terminal of sensor U1. Sensor U1 converts the detected current signal into a voltage signal, which is then output after being divided by the first resistor R1. During this process, the first magnetic core inductor L1 and the second magnetic core inductor L2 are connected to the positive and negative terminals of the power supply, respectively, and together with the capacitor assembly, they form an LC filter circuit, effectively filtering out high-frequency interference components in the sampled signal. The six capacitors in the capacitor assembly are divided into two groups, each connected to one of the two magnetic core inductors, forming a dual-path filter network, further improving the signal quality.

[0077] Secondly, the processed sampled signal is input to comparator U2 in the threshold comparison module. Comparator U2 compares the sampled signal with a preset threshold level in real time. When the sampled signal exceeds the preset threshold, comparator U2 outputs a high-level signal. After being conditioned by a voltage divider network consisting of resistors R7 to R14, the sampled signal is input to flip-flop U3 (e.g., an SN74LVC1G175DCKR single Schmitt trigger). The Schmitt characteristic of flip-flop U3 effectively eliminates jitter during signal transitions, improving signal stability. Simultaneously, the first Zener diode D1 and the second Zener diode D2 provide protection, preventing abnormal voltage from damaging subsequent circuits.

[0078] Finally, the stable signal output by trigger U3 is sent to the logic chip U4 of the alarm module. Logic chip U4 drives LED D3 through the third resistor R3 to achieve visual alarm; simultaneously, it outputs an alarm signal through a voltage divider network of the sixth and ninth resistors R6 and R9, which can be used to drive other alarm devices or control circuits. This dual alarm method improves the reliability of the system.

[0079] Throughout the entire operation, the modules are isolated and coupled through a reasonable resistor-capacitor network, ensuring effective signal transmission while avoiding mutual interference. The design of multi-stage filtering and protection circuits enables the circuit to maintain a stable and reliable operating state even in complex electromagnetic environments.

[0080] In summary, the protection circuit proposed in this utility model has the following advantages:

[0081] By combining the sampling module, threshold comparison module, and alarm module, accurate current sampling, rapid comparison, and timely alarm functions are achieved, thereby improving the circuit's response speed and protection effect.

[0082] In addition, the sampling module uses a sensor combined with a magnetic core inductor and capacitor design, which effectively improves the sampling accuracy and anti-interference capability.

[0083] In addition, the threshold comparison module adopts a combination design of comparator and flip-flop, and improves the accuracy and reliability of comparison through multi-level resistor voltage division and Zener diode protection; and the alarm module is controlled by logic chip and displayed with light-emitting diode, realizing the output of multiple alarm modes, enhancing the practicality and ease of operation of the circuit.

[0084] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A protection circuit, characterized by, This includes a connected sampling module, a threshold comparison module, and an alarm module; The sampling module is used to sample the current of the circuit to be monitored and obtain the real-time sampling signal. The threshold comparison module is used to compare the sampled signal acquired by the sampling module with a preset threshold, and output a high-level signal to the alarm module when the sampled signal exceeds the preset threshold; The alarm module is used to send an alarm signal based on the high-level signal; The sampling module includes a sensor, a first inductor with a magnetic core, a second inductor with a magnetic core, a capacitor assembly, and a first resistor; The sensor's input terminal is used to connect to the current of the circuit to be monitored, and its output terminal is used to output a sampling signal to the threshold comparison module. The sensor is connected to one end of the capacitor assembly; the sensor's output terminal is grounded through the first resistor. The other end of each capacitor assembly is grounded, and a portion of the capacitors in the capacitor assembly are connected to one end of the first inductor with a magnetic core, while the other portion of the capacitors are connected to one end of the second inductor with a magnetic core. The other ends of the first magnetic core inductor and the second magnetic core inductor are respectively connected to the positive and negative terminals of the power supply voltage.

2. The protection circuit of claim 1, wherein, The capacitor assembly includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor; One end of the first capacitor, the second capacitor, and the third capacitor is connected to one end of the second inductor with a magnetic core; one end of the fourth capacitor, the fifth capacitor, and the sixth capacitor is connected to one end of the first inductor with a magnetic core; the other ends of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor are all grounded.

3. The protection circuit of claim 2, wherein, The sensor includes a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin, an eighth pin, and a ninth pin; The first pin is connected to the first capacitor, the second capacitor, and the third capacitor; The second pin is connected to the fourth capacitor, the fifth capacitor, and the sixth capacitor; The third pin is the input terminal of the sensor; The sensor's input terminals include a first input terminal and a second input terminal; The fourth pin, the fifth pin, and the sixth pin are the first input terminals; The seventh pin, the eighth pin, and the ninth pin are the second input terminals.

4. The protection circuit of claim 1, wherein, The threshold comparison module includes a comparator, a trigger, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a second resistor, a fourth resistor, a fifth resistor, a seventh resistor, an eighth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first Zener diode, and a second Zener diode. The comparator is connected to the trigger, the seventh capacitor, the eighth capacitor, the ninth capacitor, the tenth capacitor, the fifth resistor, the seventh resistor, the eighth resistor, the tenth resistor, the eleventh resistor, the thirteenth resistor, the fourteenth resistor, and the first Zener diode; The trigger is connected to the eleventh capacitor, the second resistor, the fourth resistor, the twelfth resistor, and the second Zener diode.

5. The protection circuit of claim 4, wherein, The first pin of the comparator is connected to the negative terminal of the first Zener diode, one end of the ninth capacitor, and one end of the seventh resistor. The second pin is connected to one end of the eighth capacitor, the tenth resistor, and the fifth resistor. The third, fourth, and fifth pins, the other end of the eighth capacitor and the tenth resistor are grounded. The fifth pin is connected to one end of the seventh capacitor. The seventh pin is connected to the CLK pin of the flip-flop. The eighth pin is connected to the other end of the seventh capacitor, the power supply voltage, and the other end of the fifth resistor. The other end of the seventh resistor is connected to one end of the tenth capacitor and one end of the eighth resistor, and the other end of the seventh resistor is used to receive the sampling signal from the sampling module; The other end of the seventh resistor, the eleventh resistor, the thirteenth resistor, and the fourteenth resistor are connected in series. The end of the fourteenth resistor furthest from the thirteenth resistor is grounded; The positive terminal of the first Zener diode, the other end of the ninth capacitor, and the other end of the tenth capacitor are all grounded.

6. The protection circuit of claim 5, wherein, The second pin of the trigger is grounded, the third and fifth pins are both connected to the power supply voltage, and the fourth pin is connected to one end of the fourth resistor and the alarm module; the other end of the fourth resistor is connected to the positive terminal of the second Zener diode; the negative terminal of the second Zener diode is connected to the control pin of the driver chip; the driver chip control signal sent by the MCU is first grounded through the second resistor and then connected to the control pin of the driver chip. The sixth pin of the comparator is connected to one end of the twelfth resistor, one end of the eleventh capacitor, and the reset signal; the other end of the twelfth resistor is connected to the power supply voltage; and the other end of the eleventh capacitor is grounded.

7. The protection circuit of claim 4, wherein, The comparator model includes TLV3502AIDR; ​​the trigger includes SN74LVC1G175DCKR single Schmitt trigger.

8. The protection circuit of claim 1, wherein, The alarm module includes a logic chip, a light-emitting diode, a third resistor, a sixth resistor, and a ninth resistor; The second pin of the logic chip is connected to the threshold comparison module and one end of the third resistor, and the fourth pin is connected to one end of the sixth resistor; the third pin of the logic chip is grounded; the fifth pin of the logic chip is connected to the power supply voltage. The positive terminal of the light-emitting diode is connected to the other end of the third resistor, and the negative terminal is grounded; The other end of the sixth resistor is grounded through the ninth resistor; the logic chip outputs an alarm signal between the sixth resistor and the ninth resistor.

9. The protection circuit of claim 8, wherein, The logic chip model includes the SN74AHC1G04DCKR single-gate NOT gate logic chip.

Images