CN109586242B - Circuit protection method, protection circuit and circuit protection device - Google Patents
Circuit protection method, protection circuit and circuit protection device Download PDFInfo
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- CN109586242B CN109586242B CN201710910818.0A CN201710910818A CN109586242B CN 109586242 B CN109586242 B CN 109586242B CN 201710910818 A CN201710910818 A CN 201710910818A CN 109586242 B CN109586242 B CN 109586242B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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Abstract
According to the circuit protection method, the protection circuit and the circuit protection device, the current change rate of the protected circuit is detected in real time, if the current change rate is larger than the first preset current change rate, sudden overcurrent possibly occurs in the protected circuit, the second current change rate is calculated in a time delay mode, and the protected circuit is protected according to the value of the second current change rate; if the first current change rate detected in real time is not greater than the first preset current change rate, whether protection action needs to be executed or not is determined by calculating the sampling power of a sampling circuit in the protected circuit so as to avoid that the protected current cannot normally work due to overcurrent, whether overcurrent exists or not is determined by two layers of discrimination mechanisms, and the accuracy of the overcurrent protection scheme is improved.
Description
Technical Field
The invention relates to the technical field of display, in particular to a circuit protection method, a protection circuit and a circuit protection device.
Background
When the power chip supplies power to the AMOLED (Active-matrix organic light emitting diode) panel, a short circuit with the ground may occur easily, and a large current may be generated during the short circuit, which may cause a problem in the power stability of the power chip itself and the whole circuit, and further affect the normal display function of the AMOLED panel.
In order to solve the above problems, overcurrent protection is generally applied to the circuit, and in the prior art, the most common method of overcurrent protection is: the sampling resistor is connected with the protected circuit in series, the protected circuit is further sampled to form sampling voltage, then the sampling voltage is compared with a set voltage threshold value, and when the sampling voltage exceeds the threshold value, protection action is executed through a protection element (an electromagnetic current release, a fuse and the like). However, in the above scheme, whether an overcurrent exists in the circuit is determined by comparing the sampled voltage with the voltage threshold value, and the influence of the change of the current is not considered, so that the comparison result is not accurate enough, and the problems of slow response to sudden overcurrent increase, easy misoperation of a protection element and the like are easily caused.
Disclosure of Invention
Therefore, the technical problems to be solved by the present invention are that the overcurrent protection scheme in the prior art has low accuracy and slow sudden overcurrent response. Thereby providing an overcurrent protection method, apparatus and circuit.
In view of this, a first aspect of an embodiment of the present invention provides a circuit protection method, including: acquiring a first current change rate of a protected circuit; judging whether the first current change rate exceeds a first preset current threshold value or not; when the first current change rate exceeds a first preset current threshold value, calculating a second current change rate according to the current signal and a delayed current signal obtained by delaying the current signal; judging whether the second current change rate exceeds a second preset current threshold value or not; and when the second current change rate exceeds a second preset current threshold value, executing a protection action.
Optionally, when the first current change rate does not exceed a first preset current threshold, calculating the current power of the protected circuit; judging whether the current power exceeds a preset power threshold value; and when the current power exceeds a preset power threshold value, executing a protection action.
Optionally, the step of calculating the second current change rate according to the current signal and the delayed current signal obtained by delaying the current signal includes: calculating a current difference value of the current signal and the delayed current signal; and differentiating the delayed time by the current difference value to obtain the second current change rate.
A second aspect of an embodiment of the present invention provides a protection circuit, including: the sampling unit is used for sampling a current signal of the protected circuit; the current signal output by the sampling unit is processed by the delay circuit and then outputs a delay current signal, the delay current signal and the current signal are input into the current change rate calculation unit to calculate a third current change rate, and the third current change rate is sent to the current trigger unit; when the third current variation is larger than a third preset current threshold, the current trigger unit triggers the protection switch; and the branch selecting unit is connected with the sampling unit and is used for communicating the sampling unit with the first branch when detecting that the fourth current change rate of the protected circuit is greater than a fourth preset current threshold.
Optionally, the protection circuit further comprises a second branch circuit, including a power calculating unit and a power triggering unit, where the power calculating unit is connected to the sampling unit and is used for calculating the current power of the protected circuit; the current power is input into the power trigger unit, and when the current power is greater than a preset power threshold, the power trigger unit triggers a protection switch; and when the change rate of the current signal detected by the branch selection unit is not greater than a first preset current threshold value, the sampling unit is communicated with the second branch.
Optionally, the current change rate calculation unit includes a subtraction circuit and a differentiation unit, the delayed current signal and the current signal are input to the subtraction circuit to output a current difference value, the current difference value is input to the differentiation unit, and the current difference value is calculated to differentiate the time of the delay circuit, so as to obtain the third current change rate.
A third aspect of the embodiments of the present invention further provides a circuit protection device, including: the acquisition module is used for acquiring a first current change rate of the protected circuit; the first judgment module is used for judging whether the first current change rate exceeds a first preset current threshold value or not; the time delay calculation module is used for calculating a second current change rate according to the current signal and a time delay current signal obtained by delaying the current signal when the first current change rate exceeds a first preset current threshold; the second judgment module is used for judging whether the second current change rate exceeds a second preset current threshold value or not; and the first protection module is used for executing protection action when the second current change rate exceeds a second preset current threshold value.
Optionally, the method further comprises: the power calculation module is used for calculating the current power of the protected circuit when the first current change rate does not exceed a first preset current threshold;
the third judging module is used for judging whether the current power exceeds a preset power threshold value;
and the second protection module is used for executing protection action when the current power exceeds a preset power threshold.
A third aspect of the embodiments of the present invention further provides a circuit protection device, including: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to perform the circuit protection method.
The fifth aspect of the embodiments of the present invention also provides a non-transitory computer readable medium, on which a computer program is stored, which when executed by a processor implements the circuit protection method.
The technical scheme of the invention has the following advantages:
1. according to the circuit protection method, the protection circuit and the circuit protection device provided by the embodiment of the invention, the current change rate of the protected circuit is detected in real time, if the current change rate is greater than the first preset current change rate, sudden overcurrent possibly occurs in the protected circuit, the second current change rate is calculated in a time delay mode, and the protected circuit is protected according to the value of the second current change rate, so that the defect that the overcurrent protection circuit in the prior art cannot accurately and quickly respond to the sudden overcurrent is overcome, and the damage of the sudden overcurrent to the protected circuit is avoided.
2. According to the circuit protection method, the protection circuit and the circuit protection device provided by the embodiment of the invention, if the first current change rate detected in real time is not larger than the first preset current change rate, the situation that sudden overcurrent does not occur in the protected circuit and large current with slow change rate possibly exists is judged, so that whether protection action needs to be executed or not is determined by calculating the sampling power of the sampling circuit in the protected circuit, if the sampling power exceeds the preset threshold value, the situation that the sudden overcurrent does not exist in the protected circuit but other types of overcurrent still exist in the protected circuit is judged, the protection action is executed on the protected circuit to avoid the situation that the protected current cannot normally work due to the overcurrent, and therefore, whether the overcurrent exists or not is determined through the two layers of judgment mechanisms, and the accuracy of the overcurrent protection scheme is improved.
3. According to the circuit protection method, the protection circuit and the circuit protection device provided by the embodiment of the invention, a dual-channel detection mechanism is established, wherein a power channel (a power detection circuit) detects overcurrent with a slow current change rate, a differential channel (a change rate detection circuit) is used for quickly responding to suddenly increased current, the protection range is covered comprehensively, and a screen body is not damaged in a high-current state.
4. According to the circuit protection method, the protection circuit and the circuit protection device provided by the embodiment of the invention, the sampling signal is divided into two branches, one branch is subjected to delay circuit to obtain the delay signal (as the sampling signal value at the last moment), the difference value between the delay signal and the current sampling signal is calculated, and the difference value differentiates the time of the delay circuit to obtain the change rate of the current; compared with the scheme that the current conversion rate is obtained by sampling the current value at two time points and then calculating the current difference value and the time difference value and dividing the current difference value and the time difference value, two sampling signal values can be obtained only by sampling at one time point, so that the sampling times are doubled within the same sampling time, the sampling error is reduced, and the accuracy of the sampling result is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a circuit protection method according to embodiment 1 of the present invention;
fig. 2 is a schematic diagram of the current variation with time in the protected circuit according to embodiment 1 of the present invention;
fig. 3 is a schematic diagram of a protection circuit according to embodiment 2 of the present invention;
fig. 4 is a schematic diagram of a circuit protection device according to embodiment 3 of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example 1
The present embodiment provides a circuit protection method, which is applicable to performing overcurrent protection on a related circuit of a power chip of an AMOLED screen, and as shown in fig. 1, the method may be implemented by software or a hardware circuit, in the present embodiment, the circuit protection method is implemented by software, a sampling resistor is arranged in an output loop of the power chip to collect a current in the loop, and the current value is input into a controller, and the controller executes the following method, and implements circuit protection by a software method, including the following steps:
s11: acquiring a first current change rate of a protected circuit, namely detecting the current change rate of the protected circuit in real time, specifically, different power sources and large currents (namely, overcurrent) generated by ground short circuit, wherein the change rates generated by the large currents are different due to differences of respective circuits; since the rate of change is fast for a sudden increase in current, the first rate of change of current in the protected circuit is first detected in real time in order to accurately detect whether an overcurrent is present. The first current change rate here may be obtained by obtaining current values at two time points, so as to calculate a current change amount, and calculating the current change rate according to a difference between the two time points.
S12: and judging whether the first current change rate exceeds a first preset current threshold value.
When the current change rate is large, the sudden large current in the loop is judged accurately through the current change rate, and when the current change rate is small, the sudden large current is difficult to judge through the current change rate and can be judged through the power. Therefore, the judgment is carried out according to different current change rates, and the judgment accuracy can be better improved.
The change rate of the allowed overcurrent is different for different protected circuits under the condition of ensuring the normal operation of the protected circuits, therefore, the preset change rate can be determined according to specific circuits, the aim is to ensure that the protected circuits can normally operate under the condition of being less than the preset change rate, if the first current change rate exceeds a first preset current threshold value, the steps S13-S15 are carried out, otherwise, the steps S16-S18 are carried out.
S13: and when the first current change rate exceeds a first preset current threshold value, calculating a second current change rate according to the current signal and a delayed current signal obtained by delaying the current signal.
The current signal is a current signal acquired in real time, the current signal delayed by the current signal is a delayed current signal, and the second current change rate can be calculated according to the difference value between the delayed current signal and the current signal at the moment.
In order to obtain the second current change rate at each time point in real time, the following method is adopted here:
calculating a current difference value of the current signal and the delayed current signal;
and differentiating the delayed time by the current difference value to obtain the second current change rate.
The variation rate of the large current (i.e. the over-current) generated by the short circuit between the power supply and the ground is different due to the difference of the circuitsFor example, for a large current which suddenly increases, the time differential value of the large current is far larger than that of the current under the normal condition, so that the change rate of the large current can be determined in a differentiation mode; as shown in FIG. 2, at the same time, Δ I2the/Delta T is obviously larger than Delta I1And/Δ T, which covers a detection range by differentiation as indicated by the range indicated by the arrow in fig. 2. The difference value of the delay signal and the current sampling signal is calculated, and the difference value differentiates the time of the delay circuit, so that the change rate of the current can be obtained, the calculation is simple, and the change rate of the current can be reflected more accurately.
S14, judging whether the second current change rate exceeds a second preset current threshold value, executing a step S15 when the second current change rate exceeds the second preset current threshold value, or not executing any action.
The second preset current threshold is set to be a current value larger than the first preset current threshold according to the requirement in the circuit, and if the first preset current threshold is 0.02mA-0.05 mA; the second preset threshold is 0.08mA-0.10 mA.
And S15, when the second current change rate exceeds a second preset current threshold, executing protection action on the protected circuit. If the second current change rate exceeds the second preset current threshold, which indicates that sudden overcurrent may occur in the protected circuit, the protected circuit is protected, so that the defect that the overcurrent protection circuit in the prior art cannot accurately and quickly respond to the sudden overcurrent is overcome, and the damage of the sudden overcurrent to the protected circuit is avoided.
And S16, when the first current change rate is smaller than a first preset current threshold, calculating the sampling power of a sampling circuit in the protected circuit.
And if the first current change rate detected in real time is less than a first preset current threshold, which indicates that sudden overcurrent does not occur in the protected circuit, but overcurrent with slow change rate possibly exists, determining whether to execute the protection action by calculating the sampling power of a sampling circuit in the protected circuit.
S17: and judging whether the current power exceeds a preset power threshold value, if so, executing the step S18, otherwise, not executing a protection action.
If the sampling power exceeds the preset threshold value, the protected circuit is not provided with sudden excess current, but other types of excess current still exist, the protected circuit is protected, so that the situation that the protected current cannot work normally due to the excess current is avoided, and therefore whether the excess current exists is determined through a two-layer judging mechanism, and the accuracy of the excess current protection scheme is improved.
S18: and when the current power exceeds a preset power threshold value, executing a protection action. And when the sampling power exceeds a preset threshold value, executing protection action on the protected circuit. The safety and reliability of the circuit are improved.
As a preferable scheme, the step S11 may specifically include: acquiring sampling current of a sampling circuit; inputting the sampling current into a delayer with preset delay time, and outputting to obtain delay current; and calculating the current change rate according to the sampling current and the delay current. The sampling current is delayed to obtain the delay current, the current change rate is calculated according to the sampling current and the delay current, the current change rate can be obtained only by one-step acquisition, the sampling operation is simplified, and due to the fact that the sampling times are reduced, errors caused by the sampling process are reduced, and the calculation result is more accurate.
Preferably, the calculating the current change rate according to the sampling current and the delay current includes: calculating a current difference value of the sampling current and the delay current; and differentiating the current difference value with time to obtain the current change rate. Specifically, the change rate of the large current (i.e. the overcurrent) generated by the short circuit between the power supply and the ground is different due to the difference of the respective circuits, for example, for the suddenly increased large current, the differential value of the suddenly increased large current with respect to time is much larger than the differential value of the current with respect to time under normal conditions, so the change rate can be determined by differentiating; as shown in FIG. 2, at the same time, Δ I2the/Delta T is obviously larger than Delta I1And/Δ T, which covers a detection range by differentiation as indicated by the range indicated by the arrow in fig. 2. The difference value is calculated by the time delay signal and the current sampling signal, and the difference value is used for the time delay circuitThe time of the current is differentiated to obtain the change rate of the current, so that the calculation is simple, and the change rate of the current can be reflected more accurately.
The overcurrent protection method provided by this embodiment detects the current change rate of the protected circuit in real time, if the first current change rate exceeds the first preset current threshold, it indicates that sudden overcurrent may occur in the protected circuit, further determines the current change rate, and performs a protection action on the protected circuit according to the determination result. If the current change rate detected in real time does not exceed the first preset current threshold, which indicates that sudden excess current does not occur in the protected circuit, whether a protection action is executed is determined by calculating the sampling power of the sampling circuit in the protected circuit, and if the sampling power exceeds the preset threshold, which indicates that the sudden excess current does not exist in the protected circuit, but other types of excess current still exist in the protected circuit, the protected circuit is executed with the protection action, so that the situation that the protected current cannot normally work due to the excess current is avoided, and thus, whether the excess current exists is determined through a two-layer judgment mechanism, and the accuracy of an excess current protection scheme is improved.
Example 2
In this embodiment, a protection circuit is provided, which implements protection of a power supply circuit by a hardware circuit, and the method is the same as the method in embodiment 1, but the method is implemented by a hardware circuit in this embodiment, and the protection circuit in this embodiment includes a sampling unit 21, a first branch 22, a second branch 23, and a branch selecting unit 24, as shown in fig. 3, specifically:
and the sampling unit 21 is used for sampling the current signal of the protected circuit.
The first branch circuit 22 comprises a delay circuit, a current change rate calculation unit and a current trigger unit, wherein a current signal output by the sampling unit is processed by the delay circuit and then outputs a delay current signal, the delay current signal and the current signal are input into the current change rate calculation unit to calculate a third current change rate, and the third current change rate is sent to the current trigger unit; and when the third current variation is larger than a third preset current threshold, the current trigger unit triggers the protection switch.
The current change rate calculation unit comprises a subtraction circuit and a differentiation unit, the delay current signal and the current signal are input into the subtraction circuit to output a current difference value, the current difference value is input into the differentiation unit, and the current difference value is calculated to differentiate the time of the delay circuit to obtain the third current change rate.
The first branch is a differential channel detection and mainly comprises a delay circuit and a current change rate calculation unit, a sampling signal is divided into two branches by a branch selection unit 24, one branch passes through the delay circuit to obtain a delay current signal (as a sampling signal value at the last moment), the delay current signal and the current signal sampled at present are subjected to difference calculation by a subtraction circuit, the difference is used for differentiating the time of the delay circuit to complete the current change rate calculation, and the change rate of the current can be obtained; if the current trigger unit judges that the change rate is larger than the preset change rate (at this time, the current comparison trigger unit outputs a low level to the level processing unit), the level processing unit judges that a large current with a fast change rate is generated.
The second branch 23 comprises a power calculating unit and a power triggering unit, wherein the power calculating unit is connected with the sampling unit and is used for calculating the current power of the protected circuit; the current power is input into the power trigger unit, and when the current power is greater than a preset power threshold, the power trigger unit triggers a protection switch;
the second branch circuit is a power detection channel, and the maximum power allowed by the sampling resistor can be obtained according to the maximum current value allowed to flow on the ELVDD and ELVSS loops; and (3) detecting large current with slow change rate by adopting power: calculating the real-time power of the sampling resistor R through the power calculating unit, for example, if the power values of two consecutive periods are both greater than the maximum power value (at this time, the power comparison triggering unit outputs a low level to the level processing unit), the level processing unit determines that a large current with a slow change rate is generated; after the results of the two detection channels are sent to the level processing unit, the level processing unit controls the execution circuit to act according to the results, for example, if the result is output low level, the switch is turned on, Ctrl is changed into low level, and the power supply chip is turned off; otherwise, the switch is turned off, and the Ctrl level state is kept unchanged.
The branch selecting unit 24 is connected with the sampling unit 21, and is used for connecting the sampling unit with the first branch 22 when detecting that the fourth current change rate of the protected circuit is greater than a fourth preset current threshold; and when the change rate of the current signal detected by the branch selection unit is not greater than a first preset current threshold, communicating the sampling unit 21 with the second branch 23.
According to the overcurrent protection circuit provided by the embodiment, a dual-channel detection mechanism is established, wherein a power channel in a second branch circuit detects overcurrent with a slow current change rate, a differential channel in a first branch circuit is used for quickly responding to suddenly increased current, and the protection range is covered comprehensively, so that a screen body is not damaged in a large-current state; the sampling signal is divided into two branches, one branch is subjected to delay sampling (as a sampling signal value at the last moment) through a delay circuit, the delay signal and the current sampling signal are subjected to difference calculation, and the difference is used for differentiating the time of the delay circuit to obtain the change rate of the current; compared with the scheme that the current conversion rate is obtained by sampling the current value at two time points and then calculating the current difference value and the time difference value and dividing the current difference value and the time difference value in the prior art, two sampling signal values can be obtained only by sampling at one time point, the operation is more convenient, the error is small, and the accuracy of the calculation result is improved.
Example 3
This embodiment provides a circuit protection device, which is a device corresponding to the circuit protection method in embodiment 1, as shown in fig. 4, and includes:
an obtaining module 31, configured to obtain a first current change rate of a protected circuit; see in particular the detailed description of step S11 in example 1.
A first determining module 32, configured to determine whether the first current change rate exceeds a first preset current threshold; see in particular the detailed description of step S12 in example 1.
The delay calculating module 33 is configured to calculate a second current change rate according to the current signal and a delayed current signal obtained by delaying the current signal when the first current change rate exceeds a first preset current threshold; see in particular the detailed description of step S13 in example 1.
A second determining module 34, configured to determine whether the second current change rate exceeds a second preset current threshold; see in particular the detailed description of step S14 in example 1.
And the first protection module 35 is used for executing a protection action when the second current change rate exceeds a second preset current threshold value. See in particular the detailed description of step S15 in example 1.
In addition, the method further comprises the following steps:
a power calculating module 36, configured to calculate a current power of the protected circuit when the first current change rate does not exceed a first preset current threshold; see in particular the detailed description of step S16 in example 1.
A third determining module 37, configured to determine whether the current power exceeds a preset power threshold; see in particular the detailed description of step S17 in example 1.
And a second protection module 38, configured to perform a protection action when the current power exceeds a preset power threshold. See in particular the detailed description of step S18 in example 1.
In addition, the present embodiment further provides a circuit protection device, which includes at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to perform the circuit protection method of embodiment 1.
Further, the present embodiment provides a non-transitory computer readable medium, on which a computer program is stored, wherein the computer program is executed by a processor to implement the circuit protection method described in embodiment 1.
The circuit protection device provided by this embodiment detects the current change rate of the protected circuit in real time, if the first current change rate exceeds the first preset current threshold, it indicates that an abrupt overcurrent may occur in the protected circuit, and performs a protection action on the protected circuit by further determining the current change rate, so that the defect that the overcurrent protection circuit in the prior art cannot accurately and quickly respond to the abrupt overcurrent is overcome, and the damage to the protected circuit caused by the abrupt overcurrent is avoided. If the first current change rate detected in real time does not exceed the first preset current threshold value, which indicates that sudden overcurrent does not occur in the protected circuit, whether protection action is executed is determined by calculating the sampling power of the sampling circuit in the protected circuit, and if the sampling power exceeds the preset threshold value, which indicates that the sudden overcurrent does not exist in the protected circuit, but other types of overcurrent still exist, the protected circuit is executed with protection action to avoid the situation that the protected current cannot normally work due to the overcurrent, so that whether the overcurrent exists is determined through a two-layer judgment mechanism, and the accuracy of the overcurrent protection scheme is improved.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (10)
1. A circuit protection method, comprising:
acquiring a first current change rate of a protected circuit;
judging whether the first current change rate exceeds a first preset current threshold value or not;
when the first current change rate exceeds a first preset current threshold value, calculating a second current change rate according to the current signal and a delayed current signal obtained by delaying the current signal;
judging whether the second current change rate exceeds a second preset current threshold value or not;
and when the second current change rate exceeds a second preset current threshold value, executing a protection action.
2. The method of claim 1, further comprising: when the first current change rate does not exceed a first preset current threshold value, calculating the current power of the protected circuit;
judging whether the current power exceeds a preset power threshold value;
and when the current power exceeds a preset power threshold value, executing a protection action.
3. The method of claim 1 or 2, wherein the step of calculating the second rate of change of current based on the present current signal and the delayed current signal delayed from the present current signal comprises:
calculating a current difference value of the current signal and the delayed current signal;
and differentiating the delayed time by the current difference value to obtain the second current change rate.
4. A protection circuit, comprising:
the sampling unit is used for sampling a current signal of the protected circuit;
the current signal output by the sampling unit is processed by the delay circuit and then outputs a delay current signal, the delay current signal and the current signal are input into the current change rate calculation unit to calculate a third current change rate, and the third current change rate is sent to the current trigger unit; when the third current variation is larger than a third preset current threshold, the current trigger unit triggers the protection switch;
and the branch selecting unit is connected with the sampling unit and is used for communicating the sampling unit with the first branch when detecting that the fourth current change rate of the protected circuit is greater than a fourth preset current threshold.
5. The protection circuit of claim 4, further comprising:
the second branch circuit comprises a power calculation unit and a power trigger unit, wherein the power calculation unit is connected with the sampling unit and is used for calculating the current power of the protected circuit; the current power is input into the power trigger unit, and when the current power is greater than a preset power threshold, the power trigger unit triggers a protection switch;
and when the change rate of the current signal detected by the branch selection unit is not greater than a first preset current threshold value, the sampling unit is communicated with the second branch.
6. The protection circuit according to claim 4 or 5, wherein the current change rate calculation unit includes a subtraction circuit and a differentiation unit, the delayed current signal and the present current signal are input to the subtraction circuit to output a current difference value, the current difference value is input to the differentiation unit, and the current difference value is calculated to differentiate the time of the delay circuit to obtain the third current change rate.
7. A circuit protection device, comprising:
the acquisition module is used for acquiring a first current change rate of the protected circuit;
the first judgment module is used for judging whether the first current change rate exceeds a first preset current threshold value or not;
the time delay calculation module is used for calculating a second current change rate according to the current signal and a time delay current signal obtained by delaying the current signal when the first current change rate exceeds a first preset current threshold;
the second judgment module is used for judging whether the second current change rate exceeds a second preset current threshold value or not;
and the first protection module is used for executing protection action when the second current change rate exceeds a second preset current threshold value.
8. The apparatus of claim 7, further comprising:
the power calculation module is used for calculating the current power of the protected circuit when the first current change rate does not exceed a first preset current threshold;
the third judging module is used for judging whether the current power exceeds a preset power threshold value;
and the second protection module is used for executing protection action when the current power exceeds a preset power threshold.
9. A circuit protection device, comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to perform the circuit protection method of any one of claims 1-3.
10. A non-transitory computer readable medium on which a computer program is stored, the program, when executed by a processor, implementing the circuit protection method of any one of claims 1-3.
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