Resettable large-current three-terminal direct-current rapid electronic fuse

Abstract

The utility model relates to the technical field of fuses, in particular to a resettable large-current three-terminal direct-current rapid electronic fuse, which comprises a current sampling module, a signal amplification module, an overcurrent judgment module, a threshold setting module, a state latching module, a state resetting module, a driving circuit module and an MOS (Metal Oxide Semiconductor) switch U5, the current sampling module detects the current during the operation of the electronic fuse, the signal amplification module isolates and amplifies the collected current signal, the overcurrent discrimination module compares the isolated and amplified current signal with a preset overcurrent threshold value, and if the current does not exceed the threshold value, the electronic fuse continues to work normally. And if the current exceeds the preset threshold, the overcurrent judgment module outputs an overcurrent state signal, and the signal enables the driving circuit module to control the MOS switch U5 to perform a turn-off action, so that the purpose of protection is achieved. With the adoption of the structure, the electronic fuse is adopted, so that compared with the traditional fuse, the electronic fuse is higher in response speed and does not need to be replaced.

Description

Technical Field

[0001] The utility model relates to the technical field of fuses, in particular to a resettable high-current three-terminal DC fast electronic fuse. Background Art

[0002] Fuses are very common in electrical appliances and are devices that protect circuits by opening them. When an overload or short circuit occurs in a circuit, the conductor inside a traditional fuse heats up due to the overload, eventually causing the conductor to melt, severing the circuit and protecting the circuit and equipment.

[0003] Fuse technology is already highly mature, but with the continuous advancement of electronic devices, new protective devices are constantly emerging, such as overspeed protectors and overvoltage protectors. These devices can more accurately protect circuits, improving equipment reliability and safety. Fuses can be categorized according to different standards. The following are some common classifications: by operating principle: thermal fuses, thermal cutout fuses, electronic fuses, and gas fuses; by appearance: glass tube fuses, ceramic fuses, and plastic fuses; by rated current: 1A, 2A, and 3A; by rated voltage: 125V, 250V, and 600V; by fast-break and slow-break fuses: fast-break and slow-break fuses; by application scenario: automotive fuses, household appliance fuses, and electronic product fuses; and by protection mechanism: fusible fuses, resettable fuses, and resettable fuses.

[0004] However, existing electronic fuses have complex circuits, require external circuits to set the working state, and have insufficient response speed. Utility Model Content

[0005] The purpose of the utility model is to provide a resettable high-current three-terminal DC fast electronic fuse to solve the problems of the electronic fuse in the prior art, such as complex circuits, the need for external circuits to set the working state, and insufficient response speed.

[0006] To achieve the above objectives, the present invention provides a resettable high-current three-terminal DC fast electronic fuse, which includes a current sampling module, a signal amplification module, an overcurrent determination module, a threshold setting module, a state latch module, a state reset module, a drive circuit module, and a MOS switch U5. The current sampling module is respectively connected to the signal amplification module and the MOS switch, the overcurrent determination module is respectively connected to the signal amplification module and the threshold setting module, the state latch module is respectively connected to the overcurrent determination module and the state reset module, and the drive circuit module is respectively connected to the state latch module and the MOS switch.

[0007] The current sampling module is used to monitor the current in the circuit in real time;

[0008] The signal amplification module is used to isolate and amplify the collected current signal;

[0009] The threshold setting module is used to set the overcurrent threshold value;

[0010] The overcurrent discrimination module is used to compare the isolated and amplified current signal with a preset overcurrent threshold value;

[0011] The state latch module is used to save the working state of the driving circuit module;

[0012] The state reset module is used to perform a reset operation to reinitialize the state latch module of the electronic fuse;

[0013] The driving circuit module is used to control and drive the MOS switch.

[0014] The resettable high-current three-terminal DC fast electronic fuse further includes a power supply module, which is used to supply power to the overcurrent determination module, the threshold setting module, the state latch module, the state reset module and the drive circuit module.

[0015] Among them, a current detection chip U1 is provided between the current acquisition module and the signal amplification module, a sampling resistor R1 is provided on the current acquisition module, pin 1 of the current detection chip U1 and pin 8 of the current detection chip U1 are both connected to the sampling resistor R1, a potentiometer RP1 is provided on the signal amplification module, pin 4 of the current detection chip U1 is grounded, and pin 5 of the current detection chip U1 is connected to the potentiometer RP1.

[0016] Among them, the threshold setting module includes a resistor R3 and a resistor R4, and the resistor R3 and the resistor R4 are both connected to the power supply module. The overcurrent judgment module is provided with a dual operational amplifier U2, and the negative end of the first-stage operational amplifier in the dual operational amplifier U2 is connected to the resistor R3 and the resistor R4, and the positive end of the first-stage operational amplifier in the dual operational amplifier U2 is connected to the potentiometer RP1.

[0017] Among them, the state latch module is provided with a D trigger U3, pin 1 of the D trigger U3 is connected to the capacitor C3, pin 3 of the D trigger U3 is connected to the output end of the second operational amplifier in the dual operational amplifier U2, and a resistor R5 is provided between pin 1 of the D trigger U3 and pin 4 of the D trigger U3. The state reset module is provided with a capacitor C4, and the capacitor C4 is connected to pin 6 of the D trigger U3 and pin 4 of the D trigger U3.

[0018] Among them, the drive circuit module is provided with an optocoupler U4, a resistor R7 and a resistor R9, and the power supply module is provided with an isolated DCDC module U7. Pin 1 of the optocoupler U4 is connected to pin 6 of the D trigger U3, and the resistor R7 is provided between pin 2 of the optocoupler U4 and the capacitor C4. Pin 3 of the optocoupler U4 is connected to the MOS switch U5 and pin 3 of the isolated DCDC module U7, and the resistor R9 is provided between pin 3 of the optocoupler U4 and pin 3 of the isolated DCDC module U7.

[0019] The power module is further connected to a light emitting diode D2 and a light emitting diode D3.

[0020] The utility model discloses a resettable high-current three-terminal DC fast electronic fuse. The current in the operation of the electronic fuse is detected by the current sampling module. The current signal collected by the signal amplification module is isolated and amplified. The overcurrent discrimination module is used to compare the isolated and amplified current signal with a preset overcurrent threshold value. If the current does not exceed the threshold, the normal operation continues. If it exceeds the preset threshold, the overcurrent discrimination module will output an overcurrent status signal. This signal will cause the drive circuit module to control the MOS switch U5 to perform a shutdown action. At this time, there will be no current supply to the load, thereby achieving protection. For protection purposes, the above structure is adopted. Since the fuse adopts electronic insurance, the response speed is faster than the response time of several seconds or hundreds of milliseconds of traditional fuses. When the MOS switch U5 is turned off, the overcurrent judgment module recognizes that the circuit is not overcurrent, but through the setting of the state latch module, this state will be maintained until the next reset, so the driving circuit module will not have any other action, and the MOS switch U5 will remain in the off state. When the device is powered off, the fault is resolved, and the power is turned on again, the state latch module is reset under the action of the state reset module, and the entire circuit starts working again. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 The utility model provides a circuit diagram of a resettable high-current three-terminal DC fast electronic fuse. DETAILED DESCRIPTION

[0023] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] See also Figure 1 The present invention provides a resettable high-current three-terminal DC fast electronic fuse, which includes a current sampling module, a signal amplification module, an overcurrent determination module, a threshold setting module, a state latch module, a state reset module, a drive circuit module, and a MOS switch U5. The current sampling module is respectively connected to the signal amplification module and the MOS switch, the overcurrent determination module is respectively connected to the signal amplification module and the threshold setting module, the state latch module is respectively connected to the overcurrent determination module and the state reset module, and the drive circuit module is respectively connected to the state latch module and the MOS switch.

[0025] The current sampling module is used to monitor the current in the circuit in real time;

[0026] The signal amplification module is used to isolate and amplify the collected current signal;

[0027] The threshold setting module is used to set the overcurrent threshold value;

[0028] The overcurrent discrimination module is used to compare the isolated and amplified current signal with a preset overcurrent threshold value;

[0029] The state latch module is used to store the driving circuit module;

[0030] The state reset module is used to perform a reset operation to reinitialize the state latch module of the electronic fuse;

[0031] The driving circuit module is used to control and drive the MOS switch.

[0032] In this embodiment, the current sampling module detects the current during operation of the electronic fuse. The current signal collected by the signal amplification module is isolated and amplified. The overcurrent determination module compares the isolated and amplified current signal with a preset overcurrent threshold. If the current does not exceed the threshold, normal operation continues. If the current exceeds the preset threshold, the overcurrent determination module outputs an overcurrent status signal. This signal causes the drive circuit module to control the MOS switch U5 to shut down. At this time, no current is supplied to the load, thereby achieving the purpose of protection. With the above structure, since this fuse is an electronic fuse, the response speed is faster than the response time of several seconds or hundreds of milliseconds of traditional fuses. When the MOS switch U5 is turned off, the overcurrent determination module recognizes that the circuit is not flowing current. However, the state latch module maintains this state until the next reset, so the drive circuit module will not take any further action. The MOS switch U5 remains in the off state. When the device is powered off, the fault is resolved, and the power is restored, the state latch module is reset by the state reset module, and the entire circuit resumes operation.

[0033] Furthermore, the resettable high-current three-terminal DC fast electronic fuse also includes a power supply module, which is used to supply power to the overcurrent judgment module, the threshold setting module, the state latch module, the state reset module and the driving module.

[0034] In this embodiment, the overcurrent determination module, the threshold setting module, the state latch module, and the state reset module are powered by the power supply module.

[0035] Furthermore, a current detection chip U1 is provided between the current acquisition module and the signal amplification module, and a sampling resistor R1 is provided on the current acquisition module. Pin 1 of the current detection chip U1 and pin 8 of the current detection chip U1 are both connected to the sampling resistor R1. A potentiometer RP1 is provided on the signal amplification module, pin 4 of the current detection chip U1 is grounded, and pin 5 of the current detection chip U1 is connected to the potentiometer RP1. The threshold setting module includes a resistor R3 and a resistor R4, and the resistor R3 and the resistor R4 are both connected to the power supply module. A dual operational amplifier U2 is provided on the overcurrent discrimination module, and the negative terminal of the first-stage operational amplifier in the dual operational amplifier U2 is connected to the resistor R3 and the resistor R4, and the positive terminal of the first-stage operational amplifier in the dual operational amplifier U2 is connected to the potentiometer RP1.

[0036] In this embodiment, during the current input process, power is supplied to the load via the sampling resistor R1 and the MOS switch U5. The current detection chip U1 is used to amplify the tiny voltage across the sampling resistor R1, thereby isolating and amplifying the collected current signal. The first-stage operational amplifier in the dual operational amplifier U2 functions as a voltage comparator. The reference voltage of the first-stage operational amplifier in the dual operational amplifier U2 is obtained by dividing the output voltage of the power module by the resistors R3 and R4, and is transmitted to the negative terminal of the first-stage operational amplifier in the dual operational amplifier U2. The positive terminal of the first-stage operational amplifier in the dual operational amplifier U2 obtains the isolated and amplified current detection voltage via the potentiometer RP1. By adjusting the potentiometer RP1, different overcurrent protection thresholds can be set. When the positive terminal voltage of the first-stage operational amplifier in the dual operational amplifier U2 exceeds the negative terminal voltage, a high level is output. Since the load capacity of the first-stage operational amplifier in the dual operational amplifier U2 is limited, the second-stage operational amplifier in the dual operational amplifier U2 functions as a voltage follower to increase the load capacity.

[0037] Furthermore, a D flip-flop U3 is provided on the state latch module, pin 1 of the D flip-flop U3 is connected to the capacitor C3, pin 3 of the D flip-flop U3 is connected to the output end of the second operational amplifier in the dual operational amplifier U2, a resistor R5 is provided between pin 1 of the D flip-flop U3 and pin 4 of the D flip-flop U3, and a capacitor C4 is provided on the state reset module, the capacitor C4 is connected to pin 6 of the D flip-flop U3 and pin 4 of the D flip-flop U3 and grounded.

[0038] In this embodiment, the D flip-flop U3 is used for state locking. The value table of the D flip-flop U3 is as follows:

[0039]

[0040] During circuit operation, when the second-stage operational amplifier in the dual operational amplifier U2 outputs a high level to pin 3 of the D-type flip-flop U3, a rising edge signal is provided to pin 1 of the D-type flip-flop U3 through the capacitor C3. As can be seen from the above table, pin 6 of the D-type flip-flop U3 will have a high level output. Due to the presence of the resistor R5, the voltage on the capacitor C3 will gradually discharge to a low level to wait for the next trigger. When the D-type flip-flop U3 is powered on, since the voltage across the capacitor C4 cannot change suddenly, pin 7 of the D-type flip-flop U3 is at a low level, the D-type flip-flop U3 is reset, and outputs a low level. As the capacitor C4 is charged, the voltage of pin 7 of the D-type flip-flop U3 gradually reaches a high level, so that the D-type flip-flop U3 can wait for triggering.

[0041] Furthermore, the drive circuit module is provided with an optocoupler U4, a resistor R7 and a resistor R9, and the power supply module is provided with an isolated DCDC module U7. Pin 1 of the optocoupler U4 is connected to pin 6 of the D trigger U3, and the resistor R7 is provided between pin 2 of the optocoupler U4 and the capacitor C4. Pin 3 of the optocoupler U4 is connected to the MOS switch U5 and pin 3 of the isolated DCDC module U7, and the resistor R9 is provided between pin 3 of the optocoupler U4 and pin 3 of the isolated DCDC module U7.

[0042] In this embodiment, since the MOS switch U5 is used as a high-side application, signal isolation is performed through the optocoupler U4, and power is provided through the isolated DCDC module U7. When the output of pin 6 of the D flip-flop U3 is low, the optocoupler U4 is disconnected, the voltages across the resistor R9 are the same, the voltage of the isolated DCDC module U7 is applied to the gate-source of the MOS switch U5, VGS>Vth, and the MOS switch U5 is turned on. When the output of pin 6 of the D flip-flop U3 is high, the optocoupler U4 is turned on, VGS approaches 0V, and the MOS switch U5 is turned off, cutting off the power supply circuit to the load.

[0043] Furthermore, the power module is also connected to a light emitting diode D2 and a light emitting diode D3.

[0044] In this embodiment, the light-emitting diode D2 and the light-emitting diode D3 respectively indicate the power status and the working status of the MOS switch U5. When the light-emitting diode D2 is on, it indicates that the isolated power supply is normal, which indirectly indicates that the front-stage +5V power supply is also normal. When the light-emitting diode D3 is on, it indicates that the MOS switch U5 is turned on and normally supplies power to the load. When the light-emitting diode D3 is off, it indicates that the MOS switch U5 is turned off, the circuit is in a protection state, and the load current is zero.

[0045] The beneficial effects of the present invention are as follows: the electronic fuse achieves overcurrent protection by shutting off the current path, which is different from the mechanism of traditional fuses that achieve protection by melting. There is no substantial damage to the device, and it can be restored to work through the reset process of powering off and then powering on again, without the need to replace any materials. It is also different from the principle of the PTC self-resettable fuse. The PTC self-resettable fuse takes time to recover, so that its temperature drops to a certain level before it can resume working, while the electronic fuse resets very quickly, and manual operation only takes a few seconds. In addition, due to the protection mechanism and volume limitations, the PTC self-resettable fuse cannot be made too large. The maximum current specification commonly used on the market is about 5A, which is not enough for use in many occasions. Electronic fuses obtain the current value through current sampling or current mirroring. Different sampling coefficients and switching tubes of different power levels can be configured according to different application scenarios. Therefore, they can be used in many high-current environments, such as radar, transmitter amplifiers, automotive electrical appliances, etc. At the same time, for ease of installation and use, this electronic fuse has a three-port structure, namely input, output, and grounding. Unlike traditional fuses that only have input and output terminals, electronic fuses require a certain amount of internal power to operate, so they need a grounding terminal. In addition, electronic fuses have a certain amount of power consumption, and a large grounding area is also beneficial to the product's own heat dissipation. Installing the grounding terminal on a radiator or chassis can also facilitate installation and use. In summary, since this electronic fuse is an electronic fuse with a full hardware architecture, its response speed is very fast, usually in the microsecond level. In special scenarios, it can even achieve a nanosecond response. Compared with the response time of traditional fuses of several seconds or hundreds of milliseconds, the speed is increased by several orders of magnitude, which can greatly improve the safety of sensitive and valuable devices and avoid major property losses.

[0046] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the utility model.

Claims

1. A resettable high current three-terminal DC fast electronic fuse, characterized in that: It includes a current sampling module, a signal amplification module, an overcurrent determination module, a threshold setting module, a state latch module, a state reset module, a drive circuit module and a MOS switch U5, wherein the current sampling module is connected to the signal amplification module and the MOS switch respectively, the overcurrent determination module is connected to the signal amplification module and the threshold setting module respectively, the state latch module is connected to the overcurrent determination module and the state reset module respectively, and the drive circuit module is connected to the state latch module and the MOS switch respectively; The current sampling module is used to monitor the current in the circuit in real time; The signal amplification module is used to isolate and amplify the collected current signal; The threshold setting module is used to set the overcurrent threshold value; The overcurrent discrimination module is used to compare the isolated and amplified current signal with a preset overcurrent threshold value; The state latch module is used to save the output state of the driving circuit module; The state reset module is used to perform a reset operation to reinitialize the state latch module of the electronic fuse; The driving circuit module is used to control and drive the MOS switch.

2. The resettable high current three-terminal DC fast electronic fuse according to claim 1, characterized in that: The resettable high-current three-terminal DC fast electronic fuse also includes a power supply module, which is used to supply power to the overcurrent judgment module, the threshold setting module, the state latch module, the state reset module and the MOS switch.

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