Electronic fuse circuit and chip thereof

Abstract

The invention relates to the technical field of electronic science, in particular to an electronic fuse circuit and a chip thereof, and a current-limiting protection module in the circuit can reduce output current through a current-limiting resistor and obtain first output voltage generated when the output current passes through the current-limiting resistor. And when the first output voltage is greater than the first conduction voltage of the current-limiting triode, the current-limiting triode is conducted to obtain a current-limiting protection current, so that the working state of the transistor is adjusted to a linear working state through the current-limiting triode and the current-limiting protection current to control the output current of the circuit not to exceed a current-limiting threshold value. Thus, by dynamically adjusting the protection current threshold and combining the conduction characteristic of the triode and the linear working state of the transistor, precise control over the output current and precise regulation and control over the protection current threshold are achieved, the safety and reliability of the circuit are remarkably improved, and the actual requirement of a modern vehicle-mounted electronic system for small current application is met.

Description

Technical Field

[0001] The present application relates to the field of electronic science and technology, and in particular to an electronic fuse circuit and a chip thereof. Background Art

[0002] With the upgrade of Electrical / Electronic Architecture (EEA) and the rapid development of autonomous driving technology, electronic fuses (E-fuse) have real-time data exchange capabilities, which can enhance the diagnosis and protection functions of vehicle systems and are gradually being widely used in the new generation of power distribution systems.

[0003] However, the E-fuse chip in the related technology is only suitable for large current and medium current application scenarios. In the small current application scenario, the current acquisition accuracy of the existing E-fuse chip circuit is poor, and it is impossible to accurately monitor the small current. This will cause the configurable protection current threshold of the chip circuit to be higher, reduce the accuracy of current protection, increase the risk of line burnout, and thus reduce the safety and reliability of the circuit. Summary of the invention

[0004] The invention provides an electronic fuse circuit and a chip thereof, which are used to improve the safety and reliability of the circuit.

[0005] In a first aspect, the present application provides an electronic fuse circuit, the circuit comprising:

[0006] A current limiting protection module, comprising a current limiting resistor and a current limiting transistor, for reducing the output current through the current limiting resistor and obtaining a first output voltage; the first output voltage is a voltage generated by the output current passing through the current limiting resistor;

[0007] When the first output voltage is greater than the first conduction voltage of the current limiting transistor, a current limiting protection current is obtained through the current limiting transistor;

[0008] The working state of the transistor is adjusted to a linear working state through the current limiting transistor and the current limiting protection current, so as to control the output current of the circuit not to exceed the current limiting threshold.

[0009] Optionally, the first on-state voltage is inversely proportional to the temperature, and the current limiting threshold is a ratio between the first on-state voltage and the current limiting resistor.

[0010] Optionally, the circuit further includes:

[0011] An overcurrent protection module, comprising an overcurrent resistor, an overcurrent transistor and a self-locking submodule, for reducing the output current through the current limiting resistor and the overcurrent resistor to obtain a second output voltage; the second output voltage is a voltage generated by the output current passing through the overcurrent resistor;

[0012] When the second output voltage is greater than the second on-voltage of the overcurrent transistor, an overcurrent protection current is obtained through the overcurrent transistor;

[0013] The self-locking submodule is controlled to enter a self-locking state through the overcurrent transistor and the overcurrent protection current to stop the circuit from outputting current.

[0014] Optionally, the self-locking submodule includes a latch, a self-locking diode and a switch transistor, and the self-locking submodule is controlled to enter a self-locking state through the overcurrent transistor and the overcurrent protection current to stop the circuit from outputting current, including:

[0015] When the overcurrent transistor is in the on state, the overcurrent protection current is transmitted to the latch through the self-locking diode;

[0016] When the overcurrent protection current exceeds the trigger current threshold of the latch, the switch transistor is controlled to be in an on state through the latch to cut off the output current of the transistor.

[0017] Optionally, the overcurrent protection module further includes a timing submodule.

[0018] The overcurrent protection module is also used to charge the timing capacitor in the timing submodule through the overcurrent protection current;

[0019] When the voltage of the timing capacitor reaches a preset voltage threshold, the overcurrent protection current is transmitted to the latch.

[0020] Optionally, the second on-state voltage is inversely proportional to the temperature, the overcurrent threshold is the ratio of the second on-state voltage to the total overcurrent resistance, and the total overcurrent resistance is the sum of the overcurrent resistance and the current limiting resistance.

[0021] Optionally, the circuit further includes:

[0022] The control module includes a shutdown pin and a clear pin of the controller, which are used to stop the circuit output current through the shutdown pin; and release the self-locking state of the self-locking submodule through the clear pin to restore the circuit output current.

[0023] Optionally, the control module is further used for:

[0024] By pulling up the level signal of the shutdown pin, the corresponding high level signal is transmitted to the switch transistor, and the switch transistor is controlled to be in the on state to stop the circuit from outputting current;

[0025] By pulling up the level signal of the clear pin, the self-locking state of the self-locking submodule is released, and the switch transistor is controlled to be in a closed state to restore the circuit output current.

[0026] Optionally, the circuit further includes:

[0027] The wake-up module is used to wake up the controller by pulling up the level signal of the wake-up pin when the self-locking submodule enters the self-locking state, so that the controller performs relevant processing operations.

[0028] Optionally, the wake-up module is further used for:

[0029] When the output current passes through the wake-up resistor, a third output voltage is obtained; the third output voltage is a voltage generated by the output current passing through the wake-up resistor;

[0030] When the third output voltage is greater than the third on-voltage of the wake-up transistor, a corresponding wake-up current is obtained through the wake-up transistor;

[0031] The wake-up current is used to pull up the level signal of the wake-up pin to wake up the controller, so that the controller performs relevant processing operations.

[0032] In a second aspect, the present application provides a chip, comprising the electronic fuse circuit in the above-mentioned first aspect.

[0033] The beneficial effects of the present invention are as follows:

[0034] The embodiment of the present application provides an electronic fuse circuit, in which the current limiting protection module can reduce the output current through the current limiting resistor, and obtain the first output voltage generated by the output current passing through the current limiting resistor. When the first output voltage is greater than the first conduction voltage of the current limiting transistor, the current limiting transistor is turned on, and the current limiting protection current is obtained through the turned-on current limiting transistor, so that the working state of the transistor is adjusted to a linear working state through the current limiting transistor and the current limiting protection current, so as to control the output current of the circuit not to exceed the current limiting threshold. In this way, the embodiment of the present application realizes precise control of the output current and precise regulation of the protection current threshold by dynamically adjusting the protection current threshold, combining the conduction characteristics of the transistor and the linear working state of the transistor, significantly improving the safety and reliability of the circuit, and meeting the actual needs of modern vehicle-mounted electronic systems for small current applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0036] Figure 1 This is a structural schematic diagram of an electronic fuse circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other. In addition, although the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in an order different from that here.

[0038] The terms "first" and "second" in the specification and claims of the present application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the term "comprising" and any of their variations are intended to cover non-exclusive protection. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices. "Multiple" in the present application can mean at least two, for example, can be two, three or more, and the embodiments of the present application are not limited.

[0039] The term "and / or" in the embodiments of the present application is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] The following is a brief introduction to the design concept of the embodiments of the present application.

[0041] In the power supply network of on-board electronic equipment, power is usually supplied by batteries and controlled by fuses and relays, which are responsible for protecting and distributing power. With the upgrade of electrical / electronic architecture (EEA) and the rapid development of autonomous driving technology, traditional mechanical fuses and relays are gradually unable to meet the needs of modern automotive power distribution networks. Electronic fuses (E-fuse) have real-time data exchange capabilities and can enhance the diagnosis and protection functions of on-board systems. They are gradually being widely used in the new generation of power distribution systems.

[0042] However, the E-fuse chip in the related technology is only suitable for large and medium current application scenarios, such as currents above 4A. In small current application scenarios, the on-resistance value of the built-in transistor in the existing E-fuse chip circuit is low, which will lead to poor current collection accuracy and inability to accurately monitor small currents. It also leads to higher configurable short-circuit thresholds and I2T protection current thresholds of the chip circuit, which further reduces the accuracy of current protection, increases the risk of line burnout, and reduces the safety and reliability of the vehicle system.

[0043] For example, E-fuse chips used for normal power distribution usually need to have functions such as low quiescent current (current <100uA), software-controllable on / off, fixed current wake-up microcontroller unit (MCU), short-circuit break (SCB) / short-circuit grounding (SCG) / overload (OL) triple diagnosis, short-circuit protection, overload protection and current-time integral (Current Squared Time, I2T) protection, capacitor charging capability, etc. However, the current E-fuse chip solutions suitable for normal power on the market are mainly discrete driver chip transistor solutions suitable for large current applications exceeding 30A, and intelligent high-side switch integrated solutions suitable for medium current applications of 4A-30A. As a result, when the relevant technology is powering small controllers or sensors, due to the lack of E-fuse chips for small current applications less than 1A, only chips for medium or large current applications can be used for power distribution. These chips often have a small on-voltage (Rdson) of the internal transistor Mosfet, and the current of the integrated solution is collected by the mirror current source. The smaller the on-voltage, the worse the current collection accuracy, and the larger the minimum configurable value of the circuit's short-circuit threshold and I2T protection current threshold, which not only reduces the accuracy of current protection and increases the risk of line burnout, but also the circuit cannot adapt to the power distribution needs of smaller and thinner wire diameters, resulting in the inability to select thinner wire diameters when selecting wiring harnesses, increasing the weight and cost of the vehicle wiring harness, limiting the freedom of vehicle design, and reducing the reliability of the system. On the other hand, due to the small on-voltage, the circuit's wake-up current threshold is too large, which may cause the main MCU to fail to wake up normally when small current applications.

[0044] In view of the above problems, an embodiment of the present application provides an electronic fuse circuit, which at least includes a current limiting protection module, which can reduce the output current through a current limiting resistor, and obtain a first output voltage generated by the output current passing through the current limiting resistor. When the first output voltage is greater than the first conduction voltage of the current limiting transistor, the current limiting transistor is turned on, and a current limiting protection current is obtained through the turned-on current limiting transistor, thereby adjusting the working state of the transistor to a linear working state through the current limiting transistor and the current limiting protection current to control the output current of the circuit not to exceed the current limiting threshold. In this way, the embodiment of the present application dynamically adjusts the current limiting protection current threshold, combines the conduction characteristics of the current limiting transistor and the linear region working state of the transistor, realizes precise control of the output current, and precise regulation of the short-circuit threshold, significantly improves the safety and reliability of the circuit, and meets the actual needs of modern vehicle-mounted electronic systems for small current applications.

[0045] The following briefly introduces the application scenarios to which the technical solutions of the embodiments of the present application can be applied. It should be noted that the application scenarios introduced below are only used to illustrate the embodiments of the present application and are not limited. In the specific implementation process, the technical solutions provided by the embodiments of the present application can be flexibly applied according to actual needs.

[0046] The solution provided in the embodiment of the present application can be applied to most small current power supply application scenarios, such as vehicle-mounted electronic systems, industrial control, communication equipment, etc., and is mainly used to improve the protection capability and system reliability of the power distribution system. For example, in a vehicle-mounted electronic system, the electronic fuse circuit provided in the embodiment of the present application can be used to control the power supply of various key small current loads (such as sensors, control units, entertainment equipment, etc.). By accurately controlling the current limiting protection current, overcurrent protection current and wake-up current, a higher current acquisition accuracy is provided to avoid the risk of circuit burning. In addition, since the short-circuit threshold and I2T protection threshold of the embodiment of the present application can be accurately adjusted, the circuit can select a smaller wire diameter, reduce the wiring harness cost and optimize the spatial layout, thereby improving the flexibility and safety of the vehicle-mounted electronic system.

[0047] Of course, the method provided in the embodiment of the present application is not limited to the above application scenarios, but can also be used in other possible application scenarios, which are not limited by the embodiment of the present application. The functions that can be realized by each device in the above application scenarios will be described in the subsequent method embodiments, and no further details will be given here.

[0048] Below, in combination with the application scenarios described above, the system and method provided by the exemplary embodiments of the present application are described with reference to the accompanying drawings. It should be noted that the above application scenarios are only shown to facilitate understanding of the spirit and principles of the present application, and the embodiments of the present application are not limited in this regard.

[0049] like Figure 1 FIG. 1 is a schematic diagram of a structure of an electronic fuse circuit provided in an embodiment of the present application, and the electronic fuse circuit includes:

[0050] (1) The current limiting protection module mainly includes a current limiting resistor R1 and a current limiting transistor Q1. It is mainly used to limit the passage of large current when the output current exceeds the current limiting threshold, prevent excessive current from damaging circuit components, and realize the current limiting protection function.

[0051] (2) An overcurrent protection module mainly includes an overcurrent resistor R14, an overcurrent transistor Q2 and a self-locking submodule, which is used to control the self-locking submodule to enter a self-locking state when the output current exceeds the overcurrent threshold, so as to stop the circuit output current and realize the overcurrent protection function.

[0052] (3) A control module, mainly including a shutdown pin MUC_OFF and a clear pin MUC_CLEAR of the controller MCU, which are mainly used to stop the circuit output current through the shutdown pin and release the self-locking state of the self-locking submodule through the clear pin to restore the circuit output current.

[0053] In a possible implementation, the current limiting protection module can reduce the output current through the current limiting resistor R1, and obtain the first output voltage generated by the output current on the current limiting resistor, and when the first output voltage is greater than the first conduction voltage of the current limiting transistor Q1, the current limiting transistor Q1 is turned on, and the current limiting protection current is obtained through the turned-on current limiting transistor Q1. Through the current limiting transistor Q1 and the current limiting protection current, the working state of the transistor can be adjusted to a linear working state to control the output current of the circuit not to exceed the current limiting threshold.

[0054] Specifically, as above Figure 1 As shown, the output current flowing to the load OUT will generate a first output voltage output voltage on the current limiting resistor R1. When the first output voltage output voltage is greater than the first conduction voltage Vbe of the current limiting transistor Q1, the current limiting transistor Q1 will be turned on. Among them, the current limiting transistor Q1 can be an NPN transistor, and the corresponding first conduction voltage can be the voltage Vbe (Q1) between its base and emitter, which is used to control its switching state. When the base voltage exceeds a certain threshold (usually 0.6V to 0.7V) relative to the voltage of the emitter, the current limiting transistor Q1 will be turned on, allowing current to flow from the collector to the emitter. The collector current of the turned-on current limiting transistor Q1 can adjust the gate voltage of the transistor M1, so that the transistor M1 enters a linear working state and limits the current passing through it, thereby ensuring that the output current will not increase indefinitely, but is limited to a safe range, that is, the output current of the control circuit does not exceed the current limiting threshold, avoiding excessive current passing through the load, thereby protecting the circuit components, especially the load and M1 itself from being damaged by overcurrent. In addition, the linear control of the transistor can make the circuit perform better in the scenario of high-current capacitor charging, enhance the charging capacity of the capacitor, effectively limit the current when the capacitor is charging, and prevent excessive current from causing false triggering of short-circuit protection. That is, the current limiting protection module can achieve stronger capacitance capacity of the circuit.

[0055] In a possible implementation manner, the first on-state voltage Vbe(Q1) of the current limiting transistor Q1 is inversely proportional to the temperature, and the current limiting threshold is a ratio between the first on-state voltage and the current limiting resistor.

[0056] Specifically, the calculation method of the current limiting threshold I_lim is as follows:

[0057]

[0058] Wherein, I_lim is the current limiting threshold. Under the control of the current limiting protection module, the current limiting protection current will be less than the current limiting threshold, thereby preventing excessive current from passing through the load and protecting the circuit components.

[0059] Vbe(Q1) is the first on-state voltage of the current limiting transistor Q1. Due to the Vbe-temperature characteristic of the transistor, Vbe(Q1) is inversely proportional to the temperature, that is, the on-state voltage value decreases with the increase of temperature, so that the current limiting threshold also decreases with the increase of temperature. That is, at high temperature, the transistor M1 will enter the linear working state in advance, further protecting the transistor M1 and the load from overheating, providing an additional temperature protection function for the circuit, and further protecting the circuit from damage by overcurrent.

[0060] R1 is the resistance value of the current limiting resistor. The embodiment of the present application can flexibly set the size of the short-circuit threshold by adjusting the resistance value of R1, so that the configurable value of the short-circuit threshold is smaller, which is convenient for selecting a thinner circuit harness and allows the circuit to provide a larger instantaneous current when the capacitor is charged without causing excessive current to damage the transistor.

[0061] In a possible implementation, the overcurrent protection module can reduce the output current through the current limiting resistor R1 and the overcurrent resistor R14 to obtain a second output voltage generated by the output current on the overcurrent resistor. When the second output voltage is greater than the second turn-on voltage of the overcurrent transistor Q2, the overcurrent transistor Q2 is turned on, and the overcurrent protection current is obtained through the turned-on overcurrent transistor Q2. Through the overcurrent transistor Q2 and the overcurrent protection current, the self-locking submodule is controlled to enter a self-locking state to stop the circuit output current.

[0062] Specifically, when the second output voltage generated by the output current flowing through the current limiting resistor R1 and the overcurrent resistor R14 exceeds the second on-voltage Vbe(Q2) of the overcurrent transistor Q2, the overcurrent transistor Q2 is turned on. The current limiting transistor Q2 can be an NPN transistor, and the corresponding second on-voltage can be the voltage Vbe(Q2) between its base and emitter, which is used to control its switching state. When the base voltage exceeds a certain threshold (usually 0.6V to 0.7V) relative to the emitter voltage, the overcurrent transistor Q2 will be turned on, allowing the overcurrent protection current to flow from the collector to the emitter, thereby controlling the self-locking submodule to enter the self-locking state to stop the circuit output current.

[0063] In a possible implementation, the second on-state voltage Vbe(Q2) of the overcurrent transistor Q2 may be inversely proportional to the temperature, and the overcurrent threshold is the ratio of the second on-state voltage to the total overcurrent resistance, which is the sum of the overcurrent resistance and the current limiting resistance.

[0064] Specifically, the calculation method of the overcurrent threshold I_limlock is as follows:

[0065]

[0066] Among them, I_limlock is the overcurrent threshold, that is, the short-circuit threshold of the circuit. Under the control of the overcurrent protection module, when the overcurrent protection current exceeds the overcurrent threshold, the circuit is closed in time to protect the load and circuit from high current damage. That is, the overcurrent threshold is the maximum current level allowed by the circuit. When it exceeds the overcurrent threshold, the transistor will be triggered to shut down to prevent circuit damage.

[0067] Vbe(Q2) is the second on-state voltage of the overcurrent transistor Q2. Due to the Vbe-temperature characteristic of the transistor, Vbe(Q2) is inversely proportional to the temperature, that is, the second on-state voltage value decreases with increasing temperature, so that the overcurrent threshold value also decreases with increasing temperature, providing an additional temperature protection function for the circuit, further protecting the transistor from being damaged by overcurrent.

[0068] R1+R14 is the total overcurrent resistance, that is, the sum of the overcurrent resistance and the current limiting resistance. The embodiment of the present application can flexibly set the size of the overcurrent threshold by adjusting the resistance value of R1 and / or R14, thereby providing more accurate overcurrent protection, being more suitable for small current scenarios, and facilitating the selection of thinner circuit wiring harnesses, thereby reducing overall costs.

[0069] In one possible implementation, the self-locking submodule may include a self-locking diode D1, a latch U1, and a switching transistor Q3. When the overcurrent transistor Q2 is in an on state, the overcurrent protection current is transmitted to the latch U1 through the self-locking diode D1. When the overcurrent protection current exceeds the trigger current threshold of the latch U1, the switching transistor Q3 is controlled to be in an on state through the latch U1 to cut off the output current of the transistor M1.

[0070] Specifically, as above Figure 1As shown, latch U1, self-locking diode D1 and resistor R12 constitute a self-locking submodule with ultra-low static current. When the overcurrent protection current flows from the collector to the emitter of the overcurrent transistor Q2, the voltage between the self-locking diode D1 and the resistor R12 begins to increase, causing the current to flow into the latch U1. The function of the self-locking diode D1 is to prevent reverse current and ensure that the current only flows toward the self-locking submodule. When the latch U1 receives the trigger signal of the overcurrent transistor Q2, the self-locking state will be started. The latch U1 is used to record whether the current exceeds the limit. Once the logic of the latch U1 is triggered, it will remain in the locked state and the output will remain closed until there is a clear reset signal (for example, reset by clearing the pin MCU_CLEAR). Q3 is a switching transistor. When the self-locking state is started, the base voltage of Q3 rises, causing Q3 to turn on. After Q3 is turned on, the gate voltage of the transistor M1 is pulled down, and M1 enters the cut-off state, thereby cutting off the load current and protecting the circuit from overcurrent damage. In this way, under the control of the self-locking submodule, even if the load current returns to normal value in a short time, due to the locking effect of latch U1, the circuit remains in the off state, Q3 remains on, transistor M1 is continuously turned off, and the output current is completely cut off. In order to restore the normal operation of the circuit, the self-locking state must be released by a reset signal. For example, the CLEAR signal sent by the MCU can re-control U1 to make it exit the locked state. At this time, Q3 is turned off, M1 is turned on again, and the circuit resumes normal output, ensuring reliable overcurrent protection.

[0071] In a possible implementation, the overcurrent protection module further includes a timing submodule, and the overcurrent protection module can charge the timing capacitor in the timing submodule through the overcurrent protection current. When the voltage of the timing capacitor reaches a preset voltage threshold, the overcurrent protection current is transmitted to the latch to cut off the output current of the transistor M1, thereby providing I2T protection for the circuit, that is, when the circuit current exceeds a certain threshold, if the current is too large for a long enough time, the I2T protection mechanism will be triggered and shut down the circuit, thereby allowing the circuit to operate normally when the current peak is large but the duration is short, but if the current exceeds the allowable range and the duration is long, the circuit will be shut down.

[0072] Specifically, as above Figure 1As shown, the timing capacitor C4 and the resistor R25 constitute the timing submodule of the embodiment of the present application, and its function is to prevent transient or sudden overcurrent from mis-triggering the overcurrent protection, and ensure that the output is triggered and shut down after a certain period of time. When the overcurrent transistor Q2 is turned on, the overcurrent protection current passes through the timing submodule composed of the timing capacitor C4 and the resistor R25 to form a charging loop. As the timing capacitor C4 is charged, the voltage gradually increases. When the voltage reaches the trigger threshold, the timing circuit outputs a signal, triggering the self-locking submodule to enter the self-locking state, and then shutting off the output of the transistor. Since the timing submodule introduces the charging time, the circuit will not be shut down immediately due to instantaneous overcurrent, avoiding the mis-triggering protection due to temporary current fluctuations. Only when the current continues to be too large for a period of time, the capacitor voltage rises to the set threshold, and the self-locking submodule will be triggered. The higher the battery voltage, the faster the charging speed of the timing capacitor C4, that is, in the high voltage state, the timing time will be shortened, and the protection response will be faster, thereby providing faster protection when the voltage is high, improving the stability and reliability of the system. By different configurations of R25 and C4, the timing time can be flexibly changed to improve the protection performance of the circuit.

[0073] In a possible implementation, the control module of the embodiment of the present application can transmit the corresponding high-level signal to the switch transistor by pulling up the level signal of the shutdown pin, and control the switch transistor to be in the on state to stop the circuit output current. And, by pulling up the level signal of the clear pin, the self-locking state of the self-locking submodule is released, and the switch transistor is controlled to be in the off state to restore the circuit output current.

[0074] Specifically, as above Figure 1 As shown, the MCU can pull up the MCU_OFF pin to transmit current to the base of the switch transistor Q3, so that the switch transistor Q3 is turned on, thereby cutting off the transistor M3, and further cutting off the transistor M1 to stop the circuit output current. The MCU can release the self-locking state of the self-locking submodule by pulling up the MCU_CLEAR pin, thereby cutting off the switch transistor Q3, restoring the conduction of transistors M3 and M1, and restoring the circuit output current. In this way, the flexible configuration of the MCU control module can enhance the control accuracy of the circuit, meet the needs of different customers, and improve the adaptability of the system.

[0075] In a possible implementation, the control module of the embodiment of the present application also includes optional resistors R26 and R27, and optional resistors with different circuit connection relationships can be selected according to different functional requirements, thereby effectively managing power output, reducing power consumption and improving system stability according to different work requirements.

[0076] Specifically, as above Figure 1As shown, the control module can optionally attach resistor R27 to realize the active output shutdown function of the MCU, but the output will remain on after the MCU goes into sleep mode. At this time, the MCU_OFF pin is connected to the base of Q3 through R27, and the MCU can actively pull up the MCU_OFF pin to transmit current to the base of Q3, so that Q3 is turned on, transistor M3 is cut off, and transistor M1 is cut off to turn off the circuit output. However, after the MCU enters the sleep state, the MCU_OFF pin cannot be actively controlled. The MCU_OFF pin is in a high impedance state or a low level state, and Q3 has no high level input, so that Q3 is cut off, thereby turning on transistor M1 and the circuit output is restored.

[0077] Specifically, as above Figure 1 As shown, when the control module selects resistor R26, the MCU_OFF pin is connected to the input end of the latch Q1 through R26, and the MCU can be actively shut down by combining the MCU_CLEAR pin, and the circuit output state at the previous moment is maintained after the MCU is dormant and reset. At this time, when the output needs to be shut down, the MCU sends a high-level signal to the input end A of the latch by pulling up the MCU_OFF pin, and the output end Y of the latch outputs the same high-level signal, which is transmitted to the switch transistor Q3 through the diode D4, thereby turning on Q3, so that the transistor M1 is cut off and the circuit stops outputting. At the same time, due to the self-locking function of the self-locking submodule, the output terminal Y of the latch U1 transmits the high-level signal from R12 and D1 back to the input terminal A to form a self-locking loop. Regardless of whether the MCU enters the sleep state or the reset state, the MCU_OFF pin is in a high-impedance state or a low-level state, and the output terminal of the latch U1 will continue to output a high-level signal to control the transistor M1 to remain in the cut-off state, keeping the circuit in the state of the previous moment until the MCU_CLEAR pin is pulled high, releasing the self-locking state of the self-locking submodule, turning off Q3, and restoring M1 to restore the circuit output current.

[0078] In a possible implementation, in order to further improve the safety of the circuit, the electronic fuse circuit of the embodiment of the present application may further include a wake-up module. The wake-up module can wake up the controller in time through the wake-up pin INT_WAKE of the MCU when a circuit fault occurs and the current changes, so that the controller performs relevant processing operations, thereby realizing the fault wake-up function and the current wake-up function.

[0079] In one possible implementation, the wake-up module can perform a fault wake-up when the self-locking submodule enters a self-locking state, that is, when the load overcurrent causes the output to be shut down, that is, by pulling up the level signal of the wake-up pin INT_WAKE, the controller MCU is woken up so that the controller performs relevant processing operations.

[0080] Specifically, the fault wake-up function can be used to wake up the MCU for fault processing when an overcurrent condition occurs in a load in an electronic device or power system and the output is turned off. For example, the car's headlights or audio system suddenly have excessive current, causing the current to exceed the safety threshold. If not responded and processed in time, the load may be damaged or a fire may occur. At this time, the wake-up module can wake up the controller MCU by pulling up the level signal of the wake-up pin INT_WAKE. After the controller MCU is awakened, it can perform related protection operations, such as recording fault information, cutting off the load power supply, notifying the driver, etc., to ensure the safety of the system and personnel.

[0081] In a possible implementation, the wake-up module further includes a wake-up transistor Q7 and a wake-up resistor R24, which can be used to implement current wake-up, that is, when the output current passes through the wake-up resistor R24, a third output voltage generated by the output current on the wake-up resistor is obtained, and when the third output voltage is greater than the third conduction voltage of the wake-up transistor Q7, the wake-up transistor Q7 is turned on, and the corresponding wake-up current is obtained through the turned-on wake-up transistor Q7. Through the wake-up current, the level signal of the wake-up pin is pulled high to wake up the controller so that the controller performs relevant processing operations.

[0082] Specifically, current wake-up can be used to detect changes when certain events occur in the circuit. For example, in an on-board electronic system, automatic response to specific operations can be achieved through current wake-up. When the vehicle is parked, if abnormal current changes are detected in certain subsystems (such as doors, windows, etc.), the current wake-up module will use the third output voltage formed by the current passing through the wake-up resistor R24 ​​to activate the Q7 transistor, thereby generating a wake-up current. This wake-up current will pull up the level signal of the wake-up pin and wake up the MCU for processing. The MCU can further perform operations, such as rechecking the status of the doors or windows, shutting down the circuit, or notifying the driver.

[0083] In a possible implementation, the third on-state voltage Vbe(Q7) of the wake-up transistor Q7 may be inversely proportional to the temperature, and the wake-up threshold is the ratio of the third on-state voltage Vbe(Q7) to the total wake-up resistance, and the total wake-up resistance is the sum of the wake-up resistance R24, the overcurrent resistance R14 and the current limiting resistance R1.

[0084] For the convenience of description, the above parts are divided into each unit module (or module) according to the function and described separately. Of course, when implementing the present application, the functions of each unit (or module) can be implemented in the same one or more software or hardware. It can be understood by those skilled in the art that various aspects of the present application can be implemented as a system, method or program product. Therefore, various aspects of the present application can be specifically implemented in the following forms, namely: a complete hardware implementation method, a complete software implementation method (including firmware, microcode, etc.), or an implementation method combining hardware and software, which can be collectively referred to as "circuit", "module" or "system" here.

[0085] Furthermore, an embodiment of the present application also provides a chip, which may include the electronic fuse circuit shown in each embodiment of the present application.

[0086] It should be noted that, although several units or subunits of the device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided into multiple units to be embodied.

Claims

1. An electronic fuse circuit, characterized in that: The circuit comprises: A current limiting protection module, comprising a current limiting resistor and a current limiting transistor, for reducing the output current through the current limiting resistor and obtaining a first output voltage; the first output voltage is a voltage generated by the output current passing through the current limiting resistor; When the first output voltage is greater than the first conduction voltage of the current limiting transistor, a current limiting protection current is obtained through the current limiting transistor; The working state of the transistor is adjusted to a linear working state through the current limiting transistor and the current limiting protection current, so as to control the output current of the circuit not to exceed the current limiting threshold.

2. The circuit according to claim 1, characterized in that The first on-state voltage is inversely proportional to the temperature, and the current limiting threshold is a ratio between the first on-state voltage and the current limiting resistor.

3. The circuit according to claim 1, characterized in that The circuit further comprises: An overcurrent protection module, comprising an overcurrent resistor, an overcurrent transistor and a self-locking submodule, for reducing the output current through the current limiting resistor and the overcurrent resistor to obtain a second output voltage; the second output voltage is a voltage generated by the output current passing through the overcurrent resistor; When the second output voltage is greater than the second on-voltage of the overcurrent transistor, an overcurrent protection current is obtained through the overcurrent transistor; The self-locking submodule is controlled to enter a self-locking state through the overcurrent transistor and the overcurrent protection current to stop the circuit from outputting current.

4. The circuit according to claim 3, characterized in that The self-locking submodule includes a latch, a self-locking diode and a switch transistor, and the self-locking submodule is controlled to enter a self-locking state through the overcurrent transistor and the overcurrent protection current to stop the circuit from outputting current, including: When the overcurrent transistor is in the on state, the overcurrent protection current is transmitted to the latch through the self-locking diode; When the overcurrent protection current exceeds the trigger current threshold of the latch, the switch transistor is controlled to be in an on state through the latch to cut off the output current of the transistor.

5. The circuit according to claim 4, characterized in that The overcurrent protection module also includes a timing submodule. The overcurrent protection module is also used to charge the timing capacitor in the timing submodule through the overcurrent protection current; When the voltage of the timing capacitor reaches a preset voltage threshold, the overcurrent protection current is transmitted to the latch.

6. The circuit according to claim 3, characterized in that The second on-state voltage is inversely proportional to the temperature, the overcurrent threshold is the ratio of the second on-state voltage to the total overcurrent resistance, and the total overcurrent resistance is the sum of the overcurrent resistance and the current limiting resistance.

7. The circuit according to claim 3, characterized in that The circuit further comprises: The control module includes a shutdown pin and a clear pin of the controller, which are used to stop the circuit output current through the shutdown pin; and release the self-locking state of the self-locking submodule through the clear pin to restore the circuit output current.

8. The circuit according to claim 7, characterized in that The control module is also used for: By pulling up the level signal of the shutdown pin, the corresponding high level signal is transmitted to the switch transistor, and the switch transistor is controlled to be in the on state to stop the circuit from outputting current; By pulling up the level signal of the clear pin, the self-locking state of the self-locking submodule is released, and the switch transistor is controlled to be in a closed state to restore the circuit output current.

9. The circuit according to claim 1, characterized in that The circuit further comprises: The wake-up module is used to wake up the controller by pulling up the level signal of the wake-up pin when the self-locking submodule enters the self-locking state, so that the controller performs relevant processing operations.

10. The circuit according to claim 9, characterized in that The wake-up module is also used for: When the output current passes through the wake-up resistor, a third output voltage is obtained; the third output voltage is a voltage generated by the output current passing through the wake-up resistor; When the third output voltage is greater than the third conduction voltage of the wake-up transistor, a corresponding wake-up current is obtained through the wake-up transistor; The wake-up current is used to pull up the level signal of the wake-up pin to wake up the controller, so that the controller performs relevant processing operations.

11. A chip, characterized in that: The chip comprises the circuit according to any one of claims 1 to 10.

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