Overcurrent detection protection circuit
The current overcurrent detection protection circuit addresses the issue of high-voltage package arcing by using a monostable circuit with integrated comparators to detect and respond to overcurrent, ensuring timely shutdown and protecting the system from damage.
Patent Information
- Application Number
- CN202411130513.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-16
- Publication Date
- 2024-12-13
AI Technical Summary
High-voltage packages in sterilizers can arc or short-circuit, causing large currents that affect the normal operation of other components on the motherboard.
A current overcurrent detection protection circuit comprising a load circuit, filter circuit, first and second comparison circuits, and a control circuit, which includes a monostable circuit with integrated comparators to detect load current changes and trigger shutdown when a preset current is reached.
The circuit effectively protects the system by automatically shutting down the load output in microseconds when overcurrent is detected, preventing damage to other components.
Smart Images
Figure CN119134204A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of electronic technology, and in particular relates to a current overcurrent detection protection circuit. Background Art
[0002] The high-voltage package in the sterilizer will kill bacteria or viruses through high-voltage discharge breakdown to achieve disinfection. However, when the high-voltage package arcs or short-circuits, the current is relatively large, which can easily affect the normal operation of other components on the motherboard. Summary of the invention
[0003] In order to solve at least one of the above problems existing in the prior art, the present invention provides a current overcurrent detection protection circuit.
[0004] The purpose of the present invention can be achieved through the following technical solutions:
[0005] A current overcurrent detection protection circuit comprises a load circuit, a filter circuit, a first comparison circuit, a second comparison circuit and a control circuit; the load circuit is grounded through a grounding resistor, the input end of the filter circuit is connected to the load circuit and connected between the load circuit and the grounding resistor, the output end of the filter circuit is connected to the input end of the first comparison circuit, the filter circuit is used to receive an electrical signal from the load circuit and transmit the electrical signal to the first comparison circuit after filtering, the first comparison circuit is used to compare the filtered electrical signal with a standard signal and output a potential signal to the second comparison circuit, the output end of the first comparison circuit is connected to the input end of the second comparison circuit, the output end of the second comparison circuit is connected to the control circuit, the second comparison circuit is used to compare the potential signal output by the first comparison circuit with a standard signal and output a control signal to the control circuit, and the control circuit controls the connection or disconnection of the load circuit according to the control signal output by the second comparison circuit.
[0006] The beneficial effects of the present invention are as follows: a monostable circuit constructed with an integrated comparator circuit detects load current changes in real time, triggers the circuit to work when the system preset current is reached, and then shuts down the load output in time.
[0007] Preferably, the filtering circuit includes a first resistor and a first capacitor, one end of the first resistor is connected to the load circuit, the other end of the first resistor is connected to the input end of the first comparison circuit, one end of the first capacitor is connected between the first resistor and the input end of the first comparison circuit, and the other end of the first capacitor is grounded.
[0008] Preferably, the filtering circuit further includes a Zener diode, and two ends of the Zener diode are connected in parallel with two ends of the first capacitor.
[0009] Preferably, the first comparison circuit includes a first comparator, which is respectively connected to a second resistor, a fourth resistor, a fifth resistor and a twelfth resistor, the reverse input terminal of the first comparator is connected to the output terminal of the filter circuit, the forward input terminal of the first comparator is connected to the second resistor, the fourth resistor and one end of the twelfth resistor, the other end of the second resistor is grounded, the other end of the fourth resistor is connected to a power supply, the other end of the twelfth resistor is connected to the output terminal of the first comparator, the output terminal of the first comparator is respectively connected to the input terminal of the second comparison circuit and one end of the fifth resistor, and the other end of the fifth resistor is connected to the power supply.
[0010] Preferably, the first comparator compares the voltage at its positive input terminal with the voltage at its negative input terminal.
[0011] When vin1<Vref1:
[0012]
[0013] in:
[0014] RF1>>R2+R4+R5,
[0015] At this time, the first comparator outputs a high level;
[0016] When vin1>Vref1:
[0017]
[0018] in:
[0019] RE1>>R2+R4 At this time, the first comparator outputs a low level,
[0020] Among them, vin1 is the voltage of the reverse input terminal of the first comparator; Vref1 is the reference voltage of the positive input terminal of the first comparator, vref1 and vref1′ are the actual voltages of the positive input terminal of the first comparator, 1Vol is the voltage of the output terminal of the first comparator, vcc is the power supply voltage, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, R4 is the resistance value of the fourth resistor, R5 is the resistance value of the fifth resistor, and RF1 is the resistance value of the twelfth resistor.
[0021] Preferably, the second comparison circuit includes a second comparator, a second capacitor, a third capacitor, a sixth resistor, a seventh resistor, an eighth resistor, an eleventh resistor, a thirteenth resistor and a fourteenth resistor, the inverting input terminal of the second comparator is respectively connected to one end of the second capacitor and the sixth resistor, the other end of the second capacitor is connected to the output terminal of the first comparator, the other end of the sixth resistor is connected to a power supply, the positive input terminal of the second comparator is respectively connected to one end of the seventh resistor, the eighth resistor and the thirteenth resistor, the other end of the seventh resistor is connected to the power supply, the other end of the eighth resistor is grounded, the other end of the thirteenth resistor is connected to the output terminal of the second comparator, the output terminal of the second comparator is also respectively connected to one end of the eleventh resistor and the fourteenth resistor, the other end of the eleventh resistor is connected to the power supply, the other end of the fourteenth resistor is connected to the inverting input terminal of the first comparator, one end of the third capacitor is connected to the power supply, one end of the third capacitor is connected to the power supply, and the other end of the third capacitor is grounded.
[0022] Preferably, the control circuit includes a first transistor, a ninth resistor and a tenth resistor, one end of the tenth resistor is connected to the output end of the second comparator, the other end of the tenth resistor is respectively connected to the base of the first transistor and one end of the ninth resistor, the other end of the ninth resistor is grounded, the collector of the first transistor is connected to the load circuit, and the emitter of the first transistor is grounded.
[0023] Preferably, when the second comparator outputs a low level, the first transistor is in a cut-off state, the load circuit maintains a normal working state, and the second capacitor is charged through the sixth resistor, and the time required for the second capacitor to discharge is:
[0024]
[0025] When the second comparator outputs a high level, the first transistor is in a conducting state, disconnecting the load circuit to protect the circuit. At this time:
[0026] win1=0
[0027] The first comparator outputs a high level, and the second capacitor discharges through the fifth resistor and the sixth resistor. The time required for the second capacitor to discharge is:
[0028]
[0029] Among them, t is the time required for the second capacitor to charge to vref2, t2 is the time required for the second capacitor to discharge, Vin2 is the voltage on the second capacitor, vref2 is the voltage at the positive input terminal of the second comparator, vcc is the power supply voltage, 1vol is the output terminal voltage of the first comparator, R5 is the resistance value of the fifth resistor, R6 is the resistance value of the sixth resistor, and C2 is the capacitance of the second capacitor.
[0030] Preferably, the second comparator compares the voltage at its positive input terminal with the voltage at its negative input terminal.
[0031] When vin2>Vref2:
[0032]
[0033] in
[0034] RF2>>R7+R8,
[0035] At this time, the second comparator outputs a low level;
[0036] When vin2<Vref2:
[0037]
[0038] in
[0039] RF2>>R7+R8+R11,
[0040] At this time, the second comparator outputs a high level;
[0041] Among them, vin2 is the voltage of the reverse input terminal of the second comparator, Vref2 is the reference voltage of the positive input terminal of the second comparator, verf2′ and verf2 are the actual voltages of the positive input terminal of the second comparator, vcc is the power supply voltage, 7Vol is the output terminal voltage of the second comparator, R7 is the resistance value of the seventh resistor, R8 is the resistance value of the eighth resistor, R11 is the resistance value of the eleventh resistor, and RF2 is the resistance value of the thirteenth resistor.
[0042] Preferably, the collector of the first transistor is connected to the negative ion output circuit and the high voltage power supply output circuit respectively. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.
[0044] Figure 1 A circuit structure diagram provided in one embodiment of the present invention;
[0045] Figure 2 A schematic diagram of a filter circuit provided in one embodiment of the present invention;
[0046] Figure 3 A schematic diagram of a first comparison circuit provided in one embodiment of the present invention;
[0047] Figure 4 A schematic diagram of a second comparison circuit provided in one embodiment of the present invention;
[0048] Figure 5 A schematic diagram of a control circuit provided in one embodiment of the present invention;
[0049] Figure 6 A structural diagram of a negative ion output circuit provided in one embodiment of the present invention;
[0050] Figure 7 FIG. 1 is a structural diagram of a high-voltage power supply output circuit provided in one embodiment of the present invention.
[0051] Figure symbols: RL, load of power supply; R, current detection resistor; R1, first resistor; R2, second resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; R11, eleventh resistor; RF1, twelfth resistor; RF2, thirteenth resistor; RF3, fourteenth resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; ZD1, Zener diode; Q1, first transistor; IC1A, first comparator; IC1B, second comparator; VCC, power supply; VDD, load power supply; GND, power ground. DETAILED DESCRIPTION
[0052] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.
[0053] Please refer to Figure 1-5, a current overcurrent detection protection circuit provided in this embodiment includes a load circuit, a filter circuit, a first comparison circuit, a second comparison circuit and a control circuit; the load circuit is grounded through a grounding resistor, the input end of the filter circuit is connected to the load circuit and connected between the load circuit and the grounding resistor, the output end of the filter circuit is connected to the input end of the first comparison circuit, the filter circuit is used to receive an electrical signal from the load circuit and transmit the electrical signal to the first comparison circuit after filtering, the first comparison circuit is used to compare the filtered electrical signal with a standard signal and output a potential signal to the second comparison circuit, the output end of the first comparison circuit is connected to the input end of the second comparison circuit, the output end of the second comparison circuit is connected to the control circuit, the second comparison circuit is used to compare the potential signal output by the first comparison circuit with a standard signal and output a control signal to the control circuit, and the control circuit is used to control the connection and disconnection of the load circuit according to the control signal output by the second comparison circuit.
[0054] In this embodiment, a monostable circuit constructed with an integrated comparator circuit detects load current changes in real time and triggers the circuit to work when the system preset current is reached. The triggering time is in microseconds, allowing the system to automatically shut down the load output.
[0055] Please refer to Figure 1-2 In a further embodiment of the present invention, the filtering circuit includes a first resistor R1 and a first capacitor C1, one end of the first resistor R1 is connected to the load circuit, the other end of the first resistor R1 is connected to the input end of the first comparison circuit, one end of the first capacitor C1 is connected between the first resistor R1 and the input end of the first comparison circuit, the other end of the first capacitor C1 is grounded, and the filtering circuit also includes a Zener diode ZD1, and both ends of the Zener diode ZD1 are connected in parallel with both ends of the first capacitor C1.
[0056] Among them, the load circuit is the main part to be detected and protected, and it also generates current that needs to be monitored; the first resistor R1 divides the current in the load circuit and converts the current signal into a voltage signal. The first capacitor C1 cooperates with the first resistor R1 to form an RC filter circuit to remove high-frequency noise in the current signal; the Zener diode ZD1 is connected in parallel at both ends of the first capacitor C1 to limit the voltage at both ends of the first capacitor C1 to prevent damage to subsequent circuits due to excessive capacitor charging voltage. The Zener diode ZD1 is a limiting Zener diode, and its Vz must be ≤2 / 3Vcc.
[0057] In this embodiment, a current detection resistor R is further provided on the load circuit and connected in series with the load RL. One end of the load RL is connected to the load power supply VDD of the load circuit, and the other end is connected to the current detection resistor R. One end of the current detection resistor R is connected to the load RL, and the other end is grounded. The input end of the filter circuit is connected between the current detection resistor R and the load RL. When the load current flows through the current detection resistor R, the voltage drop is:
[0058]
[0059] Wherein, vin is the voltage when the load current flows through the current detection resistor R, R is the resistance value of the current detection resistor R, RL is the resistance value of the load RL of the power supply VCC, VDD is the voltage value of the load power supply, and after vin is filtered by the first resistor R1 and the first capacitor C1, its cut-off frequency is:
[0060]
[0061] Wherein, f is the cut-off frequency of vin, R1 is the resistance of the first resistor R1, and C1 is the capacitance of the first capacitor C1.
[0062] Please refer to Figure 3 In a further embodiment of the present invention, the first comparison circuit includes a first comparator IC1A, a second resistor R2, a fourth resistor R4, a fifth resistor R5 and a twelfth resistor RF1, the inverting input terminal of the first comparator IC1A is connected to the output terminal of the filter circuit, the forward input terminal of the first comparator IC1A is respectively connected to one end of the second resistor R2, the fourth resistor R4 and the twelfth resistor RF1, the other end of the second resistor R2 is grounded, the other end of the fourth resistor R4 is connected to the power supply VCC, the other end of the twelfth resistor RF1 is connected to the output terminal of the first comparator IC1A, the output terminal of the first comparator IC1A is respectively connected to the input terminal of the second comparison circuit and one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the power supply VCC.
[0063] Among them, the first comparator IC1A is used to compare the filtered voltage signal vin1 with the reference voltage Vref1, determine whether the current is too large, and output the corresponding level signal; the second resistor R2, the fourth resistor R4 and the twelfth resistor RF1 together constitute a reference voltage network, providing the reference voltage Vref1 for the positive input terminal of the first comparator IC1A; the fifth voltage R5 is a pull-up resistor at the output terminal of the first comparator IC1A, which is used to ensure the stability of the output signal.
[0064] The first comparator IC1A compares the voltage at its positive input with the voltage at its negative input. When vin1<Vref1:
[0065]
[0066] in:
[0067] RF1>>R2+R4+R5,
[0068] At this time, the first comparator IC1A outputs a high level;
[0069] When vin1>Vref1:
[0070]
[0071] in:
[0072] RF1>>R2+R4,
[0073] At this time, the first comparator IC1A outputs a low level.
[0074] Among them, vin1 is the voltage of the reverse input terminal of the first comparator IC1A; Vref1 is the reference voltage of the positive input terminal of the first comparator IC1A, vref1 and vref1′ are the actual voltages of the positive input terminal of the first comparator IC1A, 1Vol is the voltage of the output terminal of the first comparator IC1A, vcc is the voltage of the power supply VCC, R1 is the resistance value of the first resistor R1, R2 is the resistance value of the second resistor R2, R4 is the resistance value of the fourth resistor R4, R5 is the resistance value of the fifth resistor R5, and RF1 is the resistance value of the twelfth resistor RF1.
[0075] In this embodiment, the first comparator IC1A compares the filtered voltage signal (Vin1) with the reference voltage (Vref1) to determine whether the current of the load circuit exceeds the threshold value, and feeds back the corresponding electrical signal to the second comparison circuit. When the current of the load circuit does not exceed the threshold value, the first comparator IC1A outputs a high level to the second comparison circuit. When the current of the load circuit exceeds the threshold value, the first comparator IC1A outputs a low level to the second comparison circuit.
[0076] Please refer to Figure 4-5In a further embodiment of the present invention, the second comparison circuit includes a second comparator IC1B, a second capacitor C2, a third capacitor C3, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, an eleventh resistor R11, a thirteenth resistor RF2 and a fourteenth resistor RF3, the inverting input terminal of the second comparator IC1B is respectively connected to one end of the second capacitor C2 and the sixth resistor R6, the other end of the second capacitor C2 is connected to the output terminal of the first comparator IC1A, the other end of the sixth resistor R6 is connected to the power supply VCC, the positive input terminal of the second comparator IC1B is respectively connected to the seventh resistor R7, the eighth resistor R8 and the fourteenth resistor RF3 One end of the thirteenth resistor is connected, the other end of the seventh resistor R7 is connected to the power supply VCC, the other end of the eighth resistor R8 is grounded, the other end of the thirteenth resistor RF2 is connected to the output end of the second comparator IC1B, the output end of the second comparator IC1B is also connected to the eleventh resistor R11 and one end of the fourteenth resistor RF3 respectively, the other end of the eleventh resistor R11 is connected to the power supply VCC, the other end of the fourteenth resistor RF3 is connected to the reverse input end of the first comparator IC1A, one end of the third capacitor C3 is connected to the power supply VCC, one end of the third capacitor C3 is connected to the power supply VCC, and the other end of the third capacitor C3 is grounded.
[0077] The control circuit includes a first transistor Q1, a ninth resistor R9 and a tenth resistor R10, one end of the tenth resistor R10 is connected to the output end of the second comparator IC1B, the other end of the tenth resistor R10 is respectively connected to the base of the first transistor Q1 and one end of the ninth resistor R9, the other end of the ninth resistor R9 is grounded, the collector of the first transistor Q1 is connected to the load circuit, and the emitter of the first transistor Q1 is grounded. The base of the first transistor Q1 is controlled by the output of the second comparator IC1B through the tenth resistor R10, and the ninth resistor R9 is used to set the bias voltage of the transistor.
[0078] Among them, the second comparator IC1B is used to compare the voltage vin22 on the second capacitor C2 with the reference voltage Vref, and control the execution of the protection action according to the comparison result; the second current C2 and the sixth resistor R6 constitute a delay circuit, which is used to delay the execution of the protection action for a period of time after detecting the overcurrent. In order to prevent false triggering, a certain response time is given to the system. At the same time, the sixth resistor R6 also provides a charging path for the second capacitor C2; the seventh resistor R7, the eighth resistor R8 and the thirteenth resistor RF2 provide a reference voltage Vref2 for the positive input terminal of the second comparator IC1B. By adjusting the resistance values of these resistors, the size of the reference voltage can be changed to adjust the sensitivity of the overcurrent protection; the eleventh resistor R11 is a pull-up resistor at the output terminal of the second comparator IC1B, which ensures that the second comparator IC1B outputs when there is no output. The end is high level; the fourteenth resistor RF3 is connected between the output end of the second comparator IC1B and the reverse input end of the first comparator IC1A for feedback control; the third capacitor C3 is connected to the power supply VCC and the ground to improve the stability of the circuit; the first transistor Q1 is used as a switching element, and its base is controlled by the output signal of the second comparator IC1B. When the second comparator IC1B outputs a high level, the first transistor Q1 is turned on, thereby disconnecting the load circuit for protection; the ninth resistor R9 is a pull-down resistor of the base of the first transistor Q1, ensuring that the base of the first transistor Q1 is maintained at a low level when there is no high level signal input; the tenth resistor R10 transmits the output signal of the second comparator IC1B to the base of the first transistor Q1, and at the same time plays a certain current limiting role to protect the base of the first transistor Q1 from being damaged by excessive current,
[0079] When the second comparator IC1B outputs a low level, the first transistor Q1 is in the cut-off state, the load circuit maintains a normal working state, and the second capacitor C2 is charged through the sixth resistor R6. The time required for the second capacitor C2 to charge is:
[0080]
[0081] When the second comparator IC1B outputs a high level, the first transistor Q1 is in the on state, disconnecting the load circuit to protect the circuit. At this time:
[0082] vin 1=0,
[0083] The first comparator IC1A outputs a high level, and the second capacitor C2 is discharged through the fifth resistor R5 and the sixth resistor R6. The time required for the second capacitor C2 to discharge is:
[0084]
[0085] Among them, t is the time required for the second capacitor C2 to charge to vref2, t2 is the time required for the second capacitor C2 to discharge, Vin2 is the voltage on the second capacitor C2, vref2 is the voltage of the positive input terminal of the second comparator IC1B, vcc is the voltage of the power supply VCC, 1vol is the output terminal voltage of the first comparator IC1A, R5 is the resistance value of the fifth resistor R5, R6 is the resistance value of the sixth resistor R6, and C2 is the capacitance of the second capacitor C2.
[0086] The second comparator IC1B compares the voltage at its positive input with the voltage at its negative input.
[0087] When vin2>Vref2:
[0088]
[0089] in
[0090] RF2>>R7+R8,
[0091] At this time, the second comparator IC1B outputs a low level;
[0092] When vin2<Vref2:
[0093]
[0094] in
[0095] RF2>>R7+R8+R11
[0096] At this time, the second comparator IC1B outputs a high level;
[0097] Among them, vin2 is the voltage of the reverse input terminal of the second comparator IC1B, Vref2 is the reference voltage of the positive input terminal of the second comparator IC1B, verf2′ and verf2 are the actual voltages of the positive input terminal of the second comparator IC1B, vcc is the voltage of the power supply VCC, 7Vol is the output terminal voltage of the second comparator IC1B, R7 is the resistance value of the seventh resistor R7, R8 is the resistance value of the eighth resistor R8, R11 is the resistance value of the eleventh resistor R11, and RF2 is the resistance value of the thirteenth resistor RF2.
[0098] In this embodiment, the second comparator IC1B receives the output signal of the first comparator IC1A and performs delay processing through an RC circuit composed of a second capacitor C2 and a sixth resistor R6.
[0099] When the voltage (vin2) of the reverse input terminal of the second comparator IC1B is greater than the reference voltage (Vref2) of its forward input terminal, the second comparator IC1B outputs a low level. When the second comparator IC1B outputs a low level, it indicates that the current has dropped to a safe range or the delay has not ended.
[0100] If vin2 is less than Vref2, it means that the current is continuously too high and the delay ends, then the second comparator IC1B outputs a high level, and the load circuit is disconnected through the first transistor Q1 control circuit to protect the circuit from overcurrent damage.
[0101] By setting the second capacitor C2 for delay, when the load current exceeds the threshold, the greater the difference with the threshold, the shorter the trigger time of the circuit, and the load circuit current can be disconnected in a shorter time to protect the entire system.
[0102] Please refer to Figure 1 , Figure 6-7 In a further embodiment of the present invention, the collector of the first transistor Q1 is connected to the negative ion output circuit and the high voltage circuit output circuit respectively.
[0103] In this embodiment, the collector of the first transistor Q1 is respectively connected to the negative ion output circuit and the high-voltage circuit output circuit. When a high level is input to the base of the first transistor Q1, the negative ion output circuit and the high-voltage circuit output circuit can be connected to the emitter of the first transistor Q1 through the collector of the first transistor Q1 and then grounded.
[0104] The operation steps of the current overcurrent detection protection circuit are as follows: the filter circuit samples and filters the load circuit, and then the first comparator IC1A compares and determines whether the load circuit current exceeds the threshold value. If the load circuit current exceeds the threshold value, the first comparator IC1A outputs a low level through the second capacitor C2 to the second comparator IC1B. Since the voltage across the second capacitor C2 cannot change suddenly, the reverse input terminal of the second comparator IC1B is also a low level. At this time, the load maintains its original normal state. At the same time, the second capacitor C2 is charged through the sixth resistor R6. The time required for charging is the system protection time. When the second capacitor C2 is fully charged, the second comparator IC1B outputs a high level to the control circuit, and the control circuit disconnects the load to protect the entire system.
[0105] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.
Claims
1. A current overcurrent detection protection circuit, characterized in that: It includes a load circuit, a first comparison circuit, a second comparison circuit and a control circuit; the output end of the load circuit is connected to the input end of the first comparison circuit and outputs a voltage signal to the first comparison circuit, the first comparison circuit is used to compare the voltage signal output by the load circuit with a standard signal and output a potential signal to the second comparison circuit, the output end of the first comparison circuit is connected to the input end of the second comparison circuit, the output end of the second comparison circuit is connected to the control circuit, the second comparison circuit is used to compare the potential signal output by the first comparison circuit with a standard signal and output a control signal to the control circuit, and the control circuit controls the connection and disconnection of the load circuit according to the output control signal of the second comparison circuit.
2. The current overcurrent detection protection circuit according to claim 1, characterized in that: The load circuit is grounded through a grounding resistor, and a connection point between the load circuit and the grounding resistor is an output terminal of the load circuit for outputting a voltage signal to the first comparison circuit.
3. The current overcurrent detection protection circuit according to claim 1, characterized in that: A filter circuit is also arranged between the load circuit and the first comparison circuit, the input end of the filter circuit is connected to the output end of the load circuit and is used to filter the voltage signal output by the load circuit, and the output end of the filter circuit is connected to the input end of the first comparison circuit and outputs the filtered voltage signal to the input end of the first comparison circuit.
4. The current overcurrent detection protection circuit according to claim 3, characterized in that: The filter circuit comprises a first resistor (R1) and a first capacitor (C1), one end of the first resistor (R1) is connected to the load circuit, the other end of the first resistor (R1) is connected to the input end of the first comparison circuit, one end of the first capacitor (C1) is connected between the first resistor (R1) and the input end of the first comparison circuit, and the other end of the first capacitor (C1) is grounded.
5. The current overcurrent detection protection circuit according to claim 4, characterized in that: The filter circuit further comprises a Zener diode (ZD1), and two ends of the Zener diode (ZD1) are connected in parallel with two ends of the first capacitor (C1).
6. The current overcurrent detection protection circuit according to claim 3, characterized in that: The first comparison circuit comprises a first comparator (IC1A), a second resistor (R2), a fourth resistor (R4) and a twelfth resistor (RF1), the inverting input terminal of the first comparator (IC1A) is connected to the output terminal of the filter circuit, the positive input terminal of the first comparator (IC1A) is respectively connected to one end of the second resistor (R2), the fourth resistor (R4) and the twelfth resistor (RF1), the other end of the second resistor (R2) is grounded, the other end of the fourth resistor (R4) is connected to a power supply (VCC), the other end of the twelfth resistor (RF1) is connected to the output terminal of the first comparator (IC1A), and the output terminal of the first comparator (IC1A) is connected to the input terminal of the second comparison circuit; The first comparator (IC1A) compares the voltage at its positive input with the voltage at its negative input. When vin1<Vref1, the first comparator (IC1A) outputs a high level; When vin1>Vref1, the first comparator (IC1A) outputs a low level; Wherein, vin1 is the voltage of the reverse input terminal of the first comparator (IC1A); Vref1 is the reference voltage of the forward input terminal of the first comparator (IC1A); The output end of the first comparator (IC1A) is also connected to a delay circuit, the input end of the delay circuit is connected to the output end of the first comparator (IC1A), and the output end of the delay circuit is connected to the input end of the second comparator circuit; The delay circuit comprises a fifth resistor (R5), a sixth resistor (R6), a second capacitor (C2) and a power supply (VCC), one end of the fifth resistor (R5) is respectively connected to the output end of the first comparator (IC1A) and one end of the second capacitor (C2), the other end of the fifth resistor (R5) is connected to the power supply (VCC), the other end of the second capacitor (C2) is respectively connected to one end of the sixth resistor (R6) and an input end of the second comparison circuit, and the other end of the sixth resistor (R6) is connected to the power supply (VCC).
7. The current overcurrent detection protection circuit according to claim 6, characterized in that: The second comparison circuit comprises a second comparator (IC1B), a third capacitor (C3), a seventh resistor (R7), an eighth resistor (R8), an eleventh resistor (R11), a thirteenth resistor (RF2) and a fourteenth resistor (RF3), the inverting input terminal of the second comparator (IC1B) is connected to the output terminal of the delay circuit, the forward input terminal of the second comparator (IC1B) is respectively connected to one end of the seventh resistor (R7), the eighth resistor (R8) and the thirteenth resistor (RF2), the other end of the seventh resistor (R7) is connected to a power supply (VCC), and the other end of the eighth resistor (R8) is grounded, The other end of the thirteenth resistor (RF2) is connected to the output end of the second comparator (IC1B), and the output end of the second comparator (IC1B) is also connected to one end of the eleventh resistor (R11) and the fourteenth resistor (RF3), respectively. The other end of the eleventh resistor (R11) is connected to a power supply (VCC), and the other end of the fourteenth resistor (RF3) is connected to the reverse input end of the first comparator (IC1A). One end of the third capacitor (C3) is connected to the power supply (VCC), one end of the third capacitor (C3) is connected to the power supply (VCC), and the other end of the third capacitor (C3) is grounded.
8. The current overcurrent detection protection circuit according to claim 7, characterized in that: The control circuit comprises a first transistor (Q1), a ninth resistor (R9) and a tenth resistor (R10), one end of the tenth resistor (R10) is connected to the output end of the second comparator (IC1B), the other end of the tenth resistor (R10) is respectively connected to the base of the first transistor (Q1) and one end of the ninth resistor (R9), the other end of the ninth resistor (R9) is grounded, the collector of the first transistor (Q1) is connected to the load circuit, and the emitter of the first transistor (Q1) is grounded; When the second comparator (IC1B) outputs a low level, the first transistor (Q1) is in a cut-off state, the load circuit maintains a normal working state, and the second capacitor (C2) is charged through the sixth resistor (R6); When the second comparator (IC1B) outputs a high level, the first transistor (Q1) is in a conducting state, disconnecting the load circuit to protect the circuit, and at this time, the negative input terminal of the first comparator (IC1A) has no input; The first comparator (IC1A) outputs a high level, and the second capacitor (C2) is discharged through the fifth resistor (R5) and the sixth resistor (R6); When vin2>Vref2, the second comparator (IC1B) outputs a low level; When vin2<Vref2, the second comparator (IC1B) outputs a high level; in RF2R7+R8+R11, Wherein, vin2 is the voltage of the reverse input terminal of the second comparator (IC1B), Vref2 is the reference voltage of the forward input terminal of the second comparator (IC1B), R7 is the resistance value of the seventh resistor (R7), R8 is the resistance value of the eighth resistor (R8), R11 is the resistance value of the eleventh resistor (R11), and RF2 is the resistance value of the thirteenth resistor (RF2).
9. According to the current overcurrent detection protection circuit of claim 8, the collector of the first transistor (Q1) is connected to the negative ion output circuit and the high voltage power supply output circuit respectively.