Electronic fuse system and controller therefor

Abstract

The application discloses an electronic fuse system and a controller thereof, which comprises a current detection circuit, an effective value calculation circuit, an energy detection circuit and a switch control circuit. The current detection circuit is used to collect the instantaneous current value flowing through the switching element through a sampling resistor. The effective value calculation circuit is used to perform root mean square calculation on the instantaneous current values obtained at multiple sampling time points to obtain an effective current value. The energy detection circuit is used to obtain an energy curve in a cable according to the effective current value and output an overcurrent protection signal when the energy curve rises to a preset overload threshold. The switch control circuit is used to disconnect the switching element according to the overcurrent protection signal. The electronic fuse of the application performs power calculation and energy accumulation by using the effective current value, so that the energy evaluation is closer to the equivalent direct current thermal effect, the actual power and effective thermal accumulation during the circuit operation can be more accurately reflected, and the anti-interference performance is improved by using the digital processing mode.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and more specifically, to an electronic fuse system and its controller. Background Technology

[0002] In many electronic and electrical systems, fuses are indispensable basic protective components, primarily used to suppress current surges and prevent damage to the system due to overcurrent events. Especially in the automotive electronics field, fuses play a crucial role in ensuring the safe operation of the entire vehicle's electrical system. Traditional fusible fuses require physical replacement after blowing, which is not only inconvenient to maintain but also increases system downtime and maintenance costs. Therefore, electronic fuse (eFuse) technology is gradually being widely adopted. It uses electronic switches such as power MOSFETs to replace traditional fuses, automatically restoring conduction after a fault is cleared. By controlling the on / off state of this electronic switch, protection and deprotection of the circuit system can be achieved, significantly improving system reliability and maintainability.

[0003] However, existing electronic fuses and similar circuit protection devices (such as smart electronic fuses, hot-swap controllers, etc.) are typically equipped with overcurrent (OC) protection, which is mostly based on peak current detectors with a fixed deglitch time. Specifically, such protection circuits only control the corresponding electronic switch to turn off after detecting that the current amplitude is at or above the overcurrent limit, and this state continues for more than the deglitch time. In other words, within the deglitch time window, even if the current fluctuates frequently around the overcurrent limit, as long as its peak value does not continuously exceed the limit, the protection circuit will not trigger protection.

[0004] The aforementioned protection mechanism based on peak current detection has significant technical flaws: due to the de-scratching time, the current is allowed to fluctuate around the overcurrent limit, which allows the effective value of the load current (RMS current) to accumulate continuously without triggering peak protection, eventually exceeding the maximum permissible safety threshold. Compared to transient peak current, RMS current more accurately reflects the actual thermal effect and power loss generated by the current on the conductor. Excessively high RMS current will cause cumulative thermal damage to current-carrying cables (especially circuit harnesses in automotive systems), and may even lead to serious safety hazards. Therefore, how to effectively prevent the RMS current from exceeding the safety threshold to achieve refined and highly reliable protection of circuits and wiring harnesses has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] In view of the above problems, the purpose of this invention is to provide an electronic fuse system and its controller, which uses the effective value of current for power calculation and energy accumulation, so that the energy assessment is closer to the equivalent DC thermal effect, and can more accurately reflect the actual power and effective heat accumulation when the circuit is working. At the same time, the anti-interference performance is improved by using digital processing.

[0006] According to one aspect of the present invention, a controller for an electronic fuse system is provided, the electronic fuse system including a switching element electrically coupled between a power source and a load, wherein the controller includes: a current detection circuit for acquiring an instantaneous current value flowing through the switching element through a sampling resistor; an effective value calculation circuit for performing root mean square calculation on multiple instantaneous current values ​​obtained at multiple sampling time points to obtain an effective current value; an energy detection circuit for obtaining an energy curve in a cable based on the effective current value, and outputting an overcurrent protection signal when the energy curve rises to a preset overload threshold; and a switch control circuit for disconnecting the switching element according to the overcurrent protection signal.

[0007] Optionally, the effective value calculation circuit includes: a multiplication unit for receiving the instantaneous current value and outputting the square value of the instantaneous current; a low-pass filter unit for averaging the sequence of square values ​​of the instantaneous current obtained at multiple sampling time points to obtain the average value of the square of the current; and a square root calculation unit for taking the square root of the average value obtained by the low-pass filter unit to obtain the effective current value.

[0008] Optionally, the energy detection circuit includes: a threshold generation module, used to receive a nominal current and a coefficient sequence, and obtain a set of current thresholds sorted by numerical value by multiplying the nominal current by each coefficient in the coefficient sequence; a first comparator, used to compare the effective current value sequentially with the plurality of current thresholds, and output a comparison result with a multi-bit binary number, wherein each bit of the comparison result corresponds one-to-one with the corresponding coefficient; a counter, used to use the received binary comparison result as a counting step size, and perform a counting operation at the end of each comparison cycle to output a count value; and a second comparator, used to compare the count value output by the counter with a preset maximum count value, and output the overcurrent protection signal when the count value is greater than the maximum count value.

[0009] Optionally, the energy detection circuit further includes a timing control module, used to control the comparator to perform sequential comparisons of the effective current value with the plurality of current thresholds in descending order within a fixed time interval.

[0010] Optionally, the energy detection circuit further includes a counting direction control module, used to control the counting direction of the counter according to the comparison result, wherein the counting direction control module is used to control the counter to perform an operation of keeping the current count value unchanged or performing subtraction counting when the comparison result indicates that the effective current value is less than the minimum current threshold, and to control the counter to perform an addition counting operation when the comparison result indicates that the effective current value is greater than the minimum current threshold.

[0011] Optionally, the controller further includes: a temperature detection circuit for monitoring the temperature of the switching element and obtaining a temperature detection value; and an over-temperature comparator for comparing the temperature detection value with an over-temperature threshold, and outputting an over-temperature protection signal to the switch control circuit when the temperature detection value exceeds the preset over-temperature threshold, wherein the switch control circuit disconnects the switching element according to the over-temperature protection signal.

[0012] Optionally, the temperature detection circuit is further configured to continuously detect the temperature of the switching element when the switch control circuit turns off the switching element according to the overcurrent protection signal, and control the switch control circuit to turn the switching element back on when the temperature of the switching element drops to a safe temperature range.

[0013] Optionally, the low-pass filtering unit is implemented using a first-order IIR low-pass filter or a moving average filter.

[0014] Optionally, the square root calculation unit uses Newton's iteration method or the CORDIC algorithm hardware to perform the square root calculation.

[0015] According to another aspect of the present invention, an electronic fuse system is provided, comprising: a power supply; a load; a switching element electrically coupled between the power supply and the load; and the controller described above.

[0016] In summary, the controller of the electronic fuse system provided in this embodiment of the invention uses the effective value of the current for power calculation and energy accumulation, making the energy assessment closer to the equivalent DC thermal effect, and can more accurately reflect the actual power and effective heat accumulation when the circuit is working. At the same time, it improves the anti-interference performance by using digital processing.

[0017] In other embodiments, the electronic fuse system of the present invention uses a time-division multiplexed comparator to serially compare the effective current value with multiple current thresholds with a single comparator and generate a parallel step size control signal, which significantly reduces the circuit area and optimizes the hardware resource usage while maintaining the same comparison function.

[0018] Furthermore, the energy accumulation counter in this invention stops accumulating or performs a subtraction operation when the effective current value is lower than the threshold lower limit. It can dynamically take into account heat dissipation factors, avoid the energy accumulation value from deviating from the actual thermal state, and improve the accuracy of thermal protection judgment. In addition, the electronic fuse of this invention can continuously monitor the temperature of the power MOSFET after it is turned off and allow it to be restarted after the temperature drops to a safe range. It realizes self-recovery protection without manual intervention, and improves the reliability and maintenance convenience of automotive system protection while replacing physical fuses. Attached Figure Description

[0019] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic block diagram of an electronic fuse system according to an embodiment of the present invention is shown.

[0021] Figure 2 It shows Figure 1 A schematic block diagram of the effective value calculation circuit in the image.

[0022] Figure 3 It shows Figure 1 A schematic block diagram of the energy detection circuit in the image. Detailed Implementation

[0023] The invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, some well-known parts may not be shown.

[0024] In this paper, the term "gated signal" refers to a pair of complementary control signals used to control the conduction or cutoff of a transmission gate. The term "edge correspondence" means that the edge of a pulse signal or a gate signal is approximately aligned with the edge of another signal, allowing for a fixed phase deviation between the two signal edges. For example, due to factors such as device delays or line delays, the two signals can still be considered "edge-corresponding".

[0025] In the following descriptions, the transistor types are for illustrative purposes only and are not intended to limit the scope of the invention. It is understood that transistors that conduct under high-level signals are typically N-channel metal-oxide-semiconductor transistors (NMOS), while transistors that conduct under low-level signals are typically P-channel metal-oxide-semiconductor transistors (PMOS). For example, in a circuit using an NMOS transistor, a PMOS transistor can be used instead by toggling the level of the control signal, thereby achieving an equivalent circuit function. However, those skilled in the art should understand that specific circuit implementations are not limited to the transistor types described above, and other devices or combinations thereof with equivalent conduction characteristics can also be used, all of which fall within the scope of protection of this invention without departing from its spirit and essence.

[0026] Many specific details of the invention, such as the structure, materials, dimensions, processing methods, and techniques of the devices, are described below to provide a clearer understanding of the invention. However, as those skilled in the art will understand, the invention may be implemented without following these specific details.

[0027] This invention can be presented in various forms, some of which will be described below.

[0028] Figure 1 A schematic block diagram of an electronic fuse (eFuse) system 100 according to an embodiment of the present invention is shown. The system 100 can be configured in any device or circuit requiring overcurrent protection. For example, the system 100 can be used to monitor the electrical characteristics (e.g., current, voltage, etc.) between a power supply 101 and a load 103, and provide protection when an overcurrent condition that may damage the load 103 is detected.

[0029] In this embodiment, the power supply 101 can be any suitable power source. Preferably, the power supply 101 includes one or more batteries. The load 103 can be any electrical component or circuit part capable of receiving or consuming electrical energy provided by the power supply 101. Preferably, the power supply 101 can be a car battery, and the load 103 can be one or more circuits within the vehicle connected to the power supply 101 via a cable 102, which can be a wire harness or other conductive material. The output voltage of the power supply 101 can be configured according to actual needs, for example, greater than 10V, preferably greater than 20V, and more preferably greater than 40V. Specifically, the power supply 101 can be a 12V battery, a 24V battery, or a 48V battery.

[0030] Furthermore, the system 100 of this embodiment also includes a switching element 104 electrically coupled between the power supply 101 and the load 103, and a controller 105. Specifically, the switching element 104 can be electrically coupled to a cable 102, which connects the power supply 101 and the load 103. In some other embodiments, the switching element 104 can also be electrically coupled to a wire or other conductive element, one end of which is electrically connected to the power supply 101 and the other end is electrically connected to the cable 102. Preferably, the switching element 104 can be a transistor, such as a MOSFET transistor, which may also be referred to herein as an "external power MOSFET M1" (e.g., Figure 1 (As shown). It should be noted that although the switching element 104 is described herein as an external power MOSFET, this is only an illustrative example. Those skilled in the art will readily understand that other types of transistors (including but not limited to JFETs, BJTs, IGBTs, and transistors made of non-silicon materials such as silicon carbide and gallium nitride) can also be used as the switching element 104 and can be driven accordingly according to the requirements of the embodiment.

[0031] As further described below, the controller 105 of this embodiment is configured to detect and respond to overcurrent and overheating conditions of the system. For example, the controller 105 can limit the output current of the system to a safe range when an overload occurs; for instance, the safe range can be set by the user according to actual needs. If the overload persists, the controller 105 can control the switching element 104 to be in an open state, thereby disconnecting the current path between the load 103 and the power supply 101.

[0032] In some implementations, the controller 105 may be a single or integrated device, such as a single chip or electronic package. Specifically, as Figure 1 As shown, the controller 105 may be a single electronic package having multiple pins or leads configured to electrically couple the controller 105 to electrical components outside the package.

[0033] Specifically, the controller 105 may include a current detection circuit 110, an RMS value calculation circuit 120, an energy detection circuit 130, a temperature detection circuit 140, an over-temperature comparator 150, and a switch control circuit 160.

[0034] The current detection circuit 110 is configured to acquire the instantaneous current value Iwire flowing through the switching element 104 via the sampling resistor Rsht. For example, the current detection circuit 110 measures the amplitude of the load current flowing through the switching element 104 by measuring the voltage drop across the sampling resistor Rsht. In this embodiment, when the switching element 104 is in the ON state, the load current flowing through the sampling resistor Rsht generates a corresponding differential voltage across the sampling resistor Rsht, and the current detection circuit 110 obtains the instantaneous current value Iwire by detecting this differential voltage.

[0035] In one embodiment, the current detection circuit 110 may further include an analog-to-digital converter (ADC) and other circuit devices, which can be used to convert the differential voltage across the sampling resistor Rsht into a corresponding digital signal, which indicates the amplitude of the load current at each corresponding sampling time.

[0036] The RMS value calculation circuit 120 is used to perform root mean square calculation on multiple instantaneous current values ​​Iwire obtained by the current detection circuit 110 at multiple sampling time points to obtain the effective current value Irms. Specifically, the RMS value calculation circuit 120 can perform squaring, low-pass filtering, and square root operations on the multiple input instantaneous current values ​​Iwire to obtain the effective current value Irms.

[0037] The energy detection circuit 130 is used to simulate the current I in the cable 102 based on the effective current value Irms obtained by the effective value calculation circuit 120. 2 t-curve, where I 2 t is the product of the square of the current and time, which represents the energy generated by the current flowing through the load over a period of time. The energy detection circuit 130 outputs an overcurrent protection signal Latch1 to the switch control circuit 160 when the energy curve obtained based on the detected effective current value Irms rises to a preset overload threshold. The switch control circuit 160 disconnects the switching element 104 according to the overcurrent protection signal Latch1 to achieve overcurrent protection.

[0038] Specifically, the energy detection circuit 130 is used to compare the received effective current value Irms with multiple overcurrent thresholds, configure each bit of the binary comparison code according to the comparison result of each comparison, then accumulate the multiple comparison codes, and when the count value reaches the preset maximum count value, generate the overcurrent protection signal Latch1 to indicate that the energy in the system exceeds the set threshold, and then control the switch control circuit 160 to disconnect the switch element 104.

[0039] In one embodiment, the multiple overcurrent thresholds are of different values, and the energy detection circuit 130 compares the calculated effective current value Irms with the multiple overcurrent threshold sequences in sequence to obtain the comparison code.

[0040] In one embodiment, the system 100 further includes a thermistor Rntc disposed near the switching element 104 for real-time monitoring of the temperature of the switching element 104. The temperature detection circuit 140 obtains a temperature detection value Tres by detecting the thermistor Rntc. For example, the temperature detection circuit 140 also includes an analog-to-digital converter (ADC) for converting the voltage difference across the thermistor Rntc into digital data to obtain the temperature detection value Tres. An over-temperature comparator 150 compares the temperature detection value Tres with an over-temperature threshold Tlimt, and when the temperature detection value Tres exceeds the preset over-temperature threshold Tlimt, outputs an over-temperature protection signal Latch2 to the switch control circuit 160 to turn off the switching element 104.

[0041] In another embodiment, the temperature detection circuit 140 is further configured to continuously detect the temperature of the switching element 104 when the switch control circuit 160 turns off the switching element 104 according to the overcurrent protection signal Latch1 output by the energy detection circuit 130, and control the switch control circuit 160 to turn on the switching element 104 again when the temperature of the switching element 104 drops to a safe temperature range.

[0042] Furthermore, the controller 105 may also include several other subsystems, each including circuitry for monitoring or controlling specific aspects or characteristics associated with overload conditions between the power supply 101 and the load 103. Preferably, one or more of the subsystems may be implemented as circuitry in the form of integrated circuits, microprocessors, etc.

[0043] Figure 2 It shows Figure 1 A schematic block diagram of the RMS value calculation circuit 120 in the image. Figure 2 As shown, the effective value calculation circuit 120 of this embodiment includes a multiplication unit 121, a low-pass filter unit 122, and a square root calculation unit 123.

[0044] The multiplication unit 121 provides a squaring function, which receives the instantaneous current value Iwire and generates... The corresponding output value is 111.

[0045] The low-pass filter unit 122 is used to calculate the average value of the sequence of squared instantaneous current values ​​obtained at multiple sampling time points to obtain the average value 112 of the squared current values ​​at multiple sampling time points. Specifically, the low-pass filter unit 122 is used to first sum the m squared instantaneous current values ​​obtained in each sampling period, and then divide the summed value by m to obtain the average value 112.

[0046] It is understandable that the number of sampling time points m in each sampling period can vary depending on the specific implementation. For example, the number of sampling points in one sampling period could be 2. X There are , where X is a positive integer.

[0047] For example, the low-pass filter unit 122 can be implemented by a first-order IIR low-pass filter or a moving average filter.

[0048] The square root calculation unit 123 is used to calculate the square root of the average value 112 output by the low-pass filter unit 122 through Newton's iteration method or CORDIC algorithm hardware, thereby obtaining the real-time effective current value Irms.

[0049] Figure 3 It shows Figure 1 A schematic block diagram of the energy detection circuit 130 in the diagram. (See attached diagram.) Figure 3 As shown, the energy detection circuit 130 in this embodiment includes a threshold generation module 131, a comparator 132, a timing control module 133, a counter 134, a counting direction control module 135, and a comparator 136.

[0050] The threshold generation module 131 receives a nominal current Inom and a coefficient sequence [G1, G2, G3... Gn], where n represents the number of coefficients in the sequence and is a positive integer. A set of current thresholds ordered by numerical value is obtained by multiplying the nominal current Inom by each coefficient in the coefficient sequence. The positive input of the comparator 132 receives the effective current value Irms, the negative input is connected to the output of the threshold generation module 131, and the control terminal is connected to the timing control module 133. The output of the comparator 132 outputs a comparison result [W1, W2, W3... Wn] with n bits, where each bit of the comparison result [W1, W2, W3... Wn] corresponds one-to-one with each coefficient in the coefficient sequence [G1, G2, G3... Gn].

[0051] Within a fixed time interval, the timing control circuit 133 controls the comparator 132 to sequentially compare the effective current value Irms with each current threshold generated by the threshold generation module 131 in descending order. In each comparison operation, when the effective current value Irms is greater than the currently compared current threshold, the comparator 132 outputs a logic "1" at the bit position corresponding to that current threshold; otherwise, it outputs a logic "0" at that bit position. After the complete timing comparison operation, the comparator 132 outputs a binary number with the same number of bits as the coefficient sequence as the comparison result and transmits it to the counter 134.

[0052] The counter 134 uses the received binary comparison result as the counting step size and performs a counting operation at the end of each comparison cycle. Specifically, the counter 134 includes an accumulator 108 and a memory 109. The memory 109 is used to store the count value CNT output by the accumulator 108 and feeds this value back to the input of the accumulator 108, thereby realizing the cumulative addition function based on digital circuits. The accumulator 108 is used to accumulate the received comparison result with the result stored in the memory 109 when performing up counting to obtain a new count value CNT.

[0053] The counting direction control module 135 is used to control the counting direction of the counter 134 according to the comparison result output by the comparator 132. The counter 134 is configured to perform addition counting, subtraction counting, and no counting operations. When the comparison result output by the comparator 132 indicates that the effective current value Irms is less than the current threshold corresponding to the coefficient G1 (for example, the current threshold corresponding to the coefficient G1 can be the minimum current threshold generated by the threshold generation module 131), the counting direction control module 135 controls the counter 134 to perform one of two operations: keep the current count value unchanged, or subtract a preset binary number from the current count value to reduce its count value CNT, thereby indicating that the heat dissipation rate of the external cable is greater than its own heat generation rate. When the comparison result output by the comparator 132 indicates that the effective current value Irms is greater than the minimum current threshold, the counting direction control module 135 controls the counter 134 to perform addition counting.

[0054] Comparator 136 compares the count value CNT output by counter 134 with a preset maximum count value CNT_max, where the preset maximum count value CNT_max represents the maximum energy threshold that the external cable can withstand. When the count value CNT is greater than the maximum count value CNT_max, it is determined that the energy generated by the effective current value Irms exceeds the safe range. Then, comparator 136 sets the overcurrent protection signal Latch1 to a high level to instruct the switch control circuit 160 to turn off the switch element 104.

[0055] In summary, the controller of the electronic fuse system provided in this embodiment of the invention uses the effective value of the current for power calculation and energy accumulation, making the energy assessment closer to the equivalent DC thermal effect, and can more accurately reflect the actual power and effective heat accumulation when the circuit is working. At the same time, it improves the anti-interference performance by using digital processing.

[0056] In other embodiments, the electronic fuse system of the present invention uses a time-division multiplexed comparator to serially compare the effective current value with multiple current thresholds with a single comparator and generate a parallel step size control signal, which significantly reduces the circuit area and optimizes the hardware resource usage while maintaining the same comparison function.

[0057] Furthermore, the energy accumulation counter in this invention stops accumulating or performs a subtraction operation when the effective current value is lower than the threshold lower limit. It can dynamically take into account heat dissipation factors, avoid the energy accumulation value from deviating from the actual thermal state, and improve the accuracy of thermal protection judgment. In addition, the electronic fuse of this invention can continuously monitor the temperature of the power MOSFET after it is turned off and allow it to be restarted after the temperature drops to a safe range. It realizes self-recovery protection without manual intervention, and improves the reliability and maintenance convenience of automotive system protection while replacing physical fuses.

[0058] It should be noted that although devices are described herein as some kind of N-channel or P-channel device, or some kind of N-type or P-type doped region, those skilled in the art will understand that complementary devices are also possible according to the present invention. Those skilled in the art will understand that conductivity type refers to the mechanism by which conductivity occurs, such as conduction through holes or electrons; therefore, conductivity type relates to doping type, such as P-type or N-type, rather than doping concentration. Those skilled in the art will understand that the terms “during,” “when,” and “when…” used herein in relation to circuit operation are not strict terms indicating an action that occurs immediately at the start of a startup action, but rather that there may be one or more small but reasonable delays between the startup action and the reaction action initiated by it, such as various propagation delays. The terms “approximately” or “substantially” used herein mean that an element value has a parameter expected to be close to the declared value or location. However, as is well known in the art, there are always small deviations that make the value or location difficult to be strictly the declared value. It has been properly determined in the art that a deviation of at least 10 percent (10%) (or at least 20 percent (20%) for semiconductor doping concentration) is a reasonable deviation from the described accurate ideal target. When used in conjunction with signal states, the actual voltage value or logic state of the signal (e.g., "1" or "0") depends on whether positive or negative logic is used.

[0059] Furthermore, it should be noted that relational terms such as "first" and "second" used herein are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0060] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to these specific embodiments. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and make modifications based on it. The scope of protection of this invention should be determined by the scope defined in the claims of this invention.

Claims

1. A controller for an electronic fuse system, the electronic fuse system comprising a switching element electrically coupled between a power source and a load, wherein, The controller includes: A current detection circuit is used to acquire the instantaneous current value flowing through the switching element through a sampling resistor; The effective value calculation circuit is used to perform root mean square calculation on multiple instantaneous current values ​​obtained at multiple sampling time points to obtain the effective current value; An energy detection circuit is used to obtain the energy curve in the cable based on the effective current value, and to output an overcurrent protection signal when the energy curve rises to a preset overload threshold; and A switch control circuit is used to disconnect the switch element according to the overcurrent protection signal.

2. The controller according to claim 1, wherein, The effective value calculation circuit includes: A multiplication unit is used to receive the instantaneous current value and output the square of the instantaneous current. A low-pass filter unit is used to calculate the average value of the sequence of squared instantaneous current values ​​obtained at multiple sampling time points to obtain the average value of the current squares; and The square root calculation unit is used to calculate the square root of the average value obtained by the low-pass filter unit to obtain the effective current value.

3. The controller according to claim 1, wherein, The energy detection circuit includes: A threshold generation module is used to receive a nominal current and a coefficient sequence, and obtain a set of current thresholds sorted by numerical value by multiplying the nominal current by each coefficient in the coefficient sequence. The first comparator is used to compare the effective current value with the plurality of current thresholds in sequence and output a comparison result with a multi-bit binary number, wherein each bit of the comparison result corresponds one-to-one with the corresponding coefficient. A counter is used to take the received binary comparison result as the counting step size and perform a counting operation at the end of each comparison cycle to output the count value; and The second comparator is used to compare the count value output by the counter with a preset maximum count value, and output the overcurrent protection signal when the count value is greater than the maximum count value.

4. The controller according to claim 3, wherein, The energy detection circuit also includes: The timing control module is used to control the comparator to perform sequential comparisons of the effective current value with the plurality of current thresholds in descending order within a fixed time interval.

5. The controller according to claim 3, wherein, The energy detection circuit also includes: A counting direction control module is used to control the counting direction of the counter based on the comparison result. The counting direction control module is used to control the counter to perform either maintaining the current count value or subtracting when the comparison result indicates that the effective current value is less than the minimum current threshold, and to control the counter to perform addition when the comparison result indicates that the effective current value is greater than the minimum current threshold.

6. The controller according to claim 1, wherein, Also includes: A temperature detection circuit is used to monitor the temperature of the switching element and obtain a temperature detection value; as well as An over-temperature comparator is used to compare the detected temperature value with an over-temperature threshold, and output an over-temperature protection signal to the switch control circuit when the detected temperature value exceeds the preset over-temperature threshold. The switch control circuit then disconnects the switch element according to the over-temperature protection signal.

7. The controller according to claim 6, wherein, The temperature detection circuit is also used to continuously detect the temperature of the switching element when the switch control circuit turns off the switching element according to the overcurrent protection signal, and to control the switch control circuit to turn the switching element back on when the temperature of the switching element drops to a safe temperature range.

8. The controller according to claim 2, wherein, The low-pass filtering unit is implemented using a first-order IIR low-pass filter or a moving average filter.

9. The controller according to claim 2, wherein, The square root calculation unit uses Newton's iteration method or the CORDIC algorithm hardware to perform square root calculations.

10. An electronic fuse system, wherein, include: power supply; load; A switching element electrically coupled between the power source and the load; as well as The controller according to any one of claims 1-9.

Images