CN208284987U - Electronics self-recovery fuse circuit - Google Patents
Electronics self-recovery fuse circuit Download PDFInfo
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- CN208284987U CN208284987U CN201820517939.9U CN201820517939U CN208284987U CN 208284987 U CN208284987 U CN 208284987U CN 201820517939 U CN201820517939 U CN 201820517939U CN 208284987 U CN208284987 U CN 208284987U
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Abstract
The utility model discloses a kind of electronics self-recovery fuse circuits, including INA200 chip, current sampling circuit, logic control circuit, delay circuit, protection period control circuit and for control load power tube, the INA200 chip is equipped with amplifier and comparator, the current sampling circuit is for acquiring electric current, it converts the current into voltage and inputs INA200 chip, delay circuit is output to after the amplifier amplification that input voltage passes through INA200 chip interior, input voltage is compared by comparator with the reference voltage that inside generates, and comparison result is exported to logic control circuit, the logic control circuit controls opening or turning off for power tube, the protection period control circuit is used to control the size of protection period and realizes automatically reseting for circuit.The utility model can not only cut off output under the conditions of overcurrent, the restoring circuit after over current fault elimination, and can resist the influence of current spike in circuit.
Description
Technical field
The utility model relates to protect circuit, and in particular to self-recovery fuse circuit.
Background technique
In existing current foldback circuit, self-recovery fuse is generallyd use or based on the control circuit of comparator come real
Existing overcurrent protection.
Self-recovery fuse be by the polymer resin (Polymer) Jing Guo specially treated and be distributed in the inside conducting particles
(Carbon Black) composition.Its principle is a kind of homeostasis energy.Under normal circumstances, electric current is in the heat wherein generated
The heat far smaller than distributed, the resistance value very little of self-recovery fuse；When overcurrent or short circuit, generated in self-recovery fuse
Heat is far longer than the heat distributed, and temperature significantly rises, and resistance value becomes larger, so that electric current is reduced rapidly in circuit, thus right
Circuit is limited and is protected.When troubleshooting, electric current reduces, and temperature reduces, and self-recovery fuse reverts to low resistive state,
Without manually replacing.
But when short trouble occurs for self-recovery fuse output end, it can generate heat rapidly, and surface temperature is up to 110
DEG C~125 DEG C or so, and it is tightly attached to PCB, long-time high temperature can make PCB gradually burned, and most fatal is had an opportunity after failing
Open fire spontaneous combustion occurs.In addition, self-recovery fuse is affected by environment larger, response speed and temperature, fault current and device
Heat dissipating state is related, and temperature is higher, and fault current is bigger, then the response speed of self-recovery fuse is faster；It is better to radiate, then rings
Answer speed slower.The actuation time of self-recovery fuse, if overcurrent power is larger, is likely in millisecond between second grade
Device has just damaged before self-recovery fuse movement.
Control circuit based on comparator is led to as shown in Figure 1, the magnitude of current is converted to voltage by current sampling circuit
It crosses generating circuit from reference voltage generation reference voltage to compare with the voltage detected, when the voltage that sampling obtains is greater than with reference to electricity
When pressure, by delay output overcurrent control signal to logic control element, realizes the on-off of circuit, reach the mesh of protection circuit
's.
Since using two stage comparator and there is also delay circuit, integrated level is not high.In addition, when overcurrent occurs, function
The shutdown of rate pipe, overcurrent disappears after shutdown, then sampled voltage is less than comparison voltage, and power tube is again turned on；And over current fault at this time
There is no releasing, then continue to protect.In cycles, a constant electric current is had in circuit, and there are biggish power consumptions, need
The biggish power tube of power is selected, cost and volume are increased.
Utility model content
Technical problem to be solved in the utility model is just to provide a kind of electronics self-recovery fuse circuit, can be quick
It realizes overcurrent protection function, while resisting the influence of current spike in circuit.
In order to solve the above technical problems, the utility model adopts the following technical solution: electronics self-recovery fuse circuit, packet
Include INA200 chip, current sampling circuit, logic control circuit, delay circuit, protection period control circuit and for controlling
The power tube of load, the INA200 chip be equipped with amplifier and comparator, the current sampling circuit for acquire electric current,
It converts the current into voltage and inputs INA200 chip, exported after the amplifier amplification that input voltage passes through INA200 chip interior
To delay circuit, input voltage is compared by comparator with the reference voltage that inside generates, and comparison result is exported to patrolling
Control circuit is collected, the logic control circuit controls opening or turning off for power tube, the protection period control electricity
Road is used to control the size of protection period and realizes automatically reseting for circuit.
Preferably, the current sampling circuit includes sample resistance, and current signal is converted voltage signal by sample resistance,
Wherein, high voltage is input to 8 feet of INA200 chip, and low-voltage is input to 7 feet.
Preferably, the logic control circuit includes logic gate and level-one NOT gate, the logic gate and power tube and protection
Cycle control circuit connection, the level-one NOT gate are set between logic gate and 6 feet of INA200 chip.
Preferably, the delay circuit includes capacitor C1 and the resistance R1 and resistance R2 that connect with capacitor C1.
Preferably, resistance R3, resistance R4 that the protection period control circuit includes capacitor C2, connect with capacitor C2, with
And the diode D1 being connect with resistance R4.
The utility model can not only cut off output under the conditions of overcurrent, the restoring circuit after over current fault elimination, and
The influence of current spike in circuit can be resisted, in addition, protection circuit can the period when over current fault is not eliminated always in circuit
Movement, until Failure elimination.
Detailed description of the invention
Fig. 1 is the control circuit schematic diagram based on comparator；
Fig. 2 is the circuit diagram of the utility model.
Specific embodiment
It should be noted that in the absence of conflict, the features in the embodiments and the embodiments of the present application can phase
Mutually combination.The utility model will be described in detail below with reference to the accompanying drawings and embodiments.
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Be to the description only actually of at least one exemplary embodiment below it is illustrative, never as to this is practical
Novel and its application or any restrictions used.Based on the embodiments of the present invention, those of ordinary skill in the art are not having
Every other embodiment obtained under the premise of creative work is made, is fallen within the protection scope of the utility model.
As shown in Fig. 2, electronics self-recovery fuse circuit, including INA200 chip, current sampling circuit, logic control electricity
Road, delay circuit, protection period control circuit and the power tube for controlling load, the INA200 chip are equipped with amplifier
And comparator, the current sampling circuit are inputted for acquiring electric current, converting the current into voltage and inputting INA200 chip
Voltage is by being output to delay circuit after the amplification of the amplifier of INA200 chip interior, when load is there are when current spike, delay
Circuit control is input to the voltage delay of INA200 chip for a period of time and change rate can be less than the voltage that sampling obtains, comparator
Input voltage is compared with the reference voltage that inside generates, and comparison result is exported to logic control circuit, it is described to patrol
Volume control circuit opening or turn off for power tube is controlled (the utility model by power tube be for high level drives into
Row explanation), the protection period control circuit is used to control the size of protection period and realizes automatically reseting for circuit.
Wherein, the current sampling circuit includes sample resistance.The logic control circuit includes that logic gate and level-one are non-
Door.The delay circuit includes capacitor C1 and the resistance R1 and resistance R2 that connect with capacitor C1.The logic gate and power tube
And the connection of protection period control circuit, the level-one NOT gate are set between logic gate and 6 feet of INA200 chip；Wherein, logic
The presence of gate circuit is depending on the driving signal of power tube, if low level is open signal, logic gate is NOT gate, if high
Level is open signal, then does not need logic gate.
Operating mode when current spike is not present in load current:
Current signal is converted voltage signal by sample resistance, and high voltage is input to 8 feet of INA200 chip, and low-voltage is defeated
Enter to 7 feet, by being output to delay circuit by 2 feet after internal amplifier amplification, by delay circuit electric resistance partial pressure and electricity
Hold 3 feet that INA200 chip is sent to after absorbing spike.INA200 chip interior can generate reference voltage, the voltage and ginseng of input
It examines voltage to compare, if the voltage of input is less than reference voltage, 6 feet export low level, by the drive of the non-power tube behind the door of level-one
Dynamic signal is high level, and power is normally open-minded, and circuit works normally；If more than reference voltage, then 6 feet export high level, at this time
Driving signal by the non-power tube behind the door of level-one is low level, power tube shutdown.
There are operating modes when current spike for load current:
When load can be greater than normal work there are voltage when current spike, obtained at spike through over-sampling circuit
Voltage, if delay circuit is not added 6 feet of INA200 chip can output protection signal immediately, and there is no overcurrent occurs at this time
The case where, protection circuit is malfunctioned.In order to eliminate this phenomenon, it is added between 2 feet and 3 feet of INA200 chip
Level-one delay circuit, when the obtained voltage of sampling is greater than normal voltage, be input to 3 feet voltage can lag the one section time and
Change rate can be less than the voltage that sampling obtains.Its working principle is that: the characteristics of cannot being mutated according to capacitor both end voltage, work as electric current
Spike occurs, i.e., when sampled voltage increases suddenly, the voltage on capacitor C1 is remained unchanged at this time, while capacitor C1 passes through resistance R1
It charging, the voltage on 3 foot of INA200 chip rises but does not arrive protection thresholding, and after current spike disappears, sampled voltage reduces suddenly,
Capacitor C1 is discharged by resistance R2, reaches stable branch pressure voltage, eliminates the influence of current spike.By adjusting resistance R1, electricity
Hold the size of C1 to eliminate the influence of distinct pulse widths current spike.
Resistance R3, the resistance R4 that the protection period control circuit includes capacitor C2, connect with capacitor C2, and and resistance
The diode D1 of R4 connection；When reset pin is low level or is hanging, the output of 6 feet is low level, when reset pin is high electricity
Usually, comparator works normally, and carves at the beginning, and the voltage at the both ends capacitor C2 is 0, then reset pin is low level, 6 feet it is defeated
Out it is low level, is high level by the non-output behind the door of level-one, is then charged by diode D1, resistance R4 to capacitor C2, charging
Reset pin is high level after the completion, then comparator works normally, and when overcurrent not occurring, the output of 6 feet is low level, reset pin
High level is remained as, circuit works normally at this time；When overcurrent happens, comparator exports high level, by level-one NOT gate
Output is low level afterwards, and power tube shutdown, due to the effect of capacitor C2, reset signal remains as height at this time, comparator output
High level is latched, and capacitor C2 is discharged by resistance R3, and when discharging into the low threshold of reset pin, reset signal is effective, 6 feet
Output signal be pulled low, if in circuit over current fault eliminate, work normally and do not protect, if failure still has, 6
Foot can export high level switch-off power pipe again.The length of protection period is realized by adjusting the size of capacitor C2 and resistance R3
Degree.
The utility model by adopting the above technical scheme, has the following beneficial effects:
1. high sensitivity can complete protection act in Microsecond grade.
2. effectively inhibiting malfunction when peak current, the comparator when presence of delay circuit makes peak current arrive
Input terminal still keeps stable.
3. protection period is adjustable, the i.e. adjustable protection period of the resistance capacitance parameter by adjusting reset circuit.
4. integrated level small in size is high, the more integrated INA200 chip of use.
5. low in energy consumption, cut off the power rapidly when system overcurrent, only exist periodically very narrow voltage pulse, and need compared with
The long time realizes and automatically resets that protection period is far longer than the pulse period, and the energy consumed on circuit is considerably less.
6. at low cost, average current very little when overcurrent, it is only necessary to compared with the power tube of small rated power.
In addition to above preferred embodiment, for the utility model there are also other embodiments, those skilled in the art can root
It is made various changes and modifications according to the utility model, without departing from the spirit of the utility model, should belong to the utility model
Range defined in claims.
Claims (5)
1. electronics self-recovery fuse circuit, which is characterized in that including INA200 chip, current sampling circuit, logic control electricity
Road, delay circuit, protection period control circuit and the power tube for controlling load, the INA200 chip are equipped with amplifier
And comparator, the current sampling circuit are inputted for acquiring electric current, converting the current into voltage and inputting INA200 chip
It is output to delay circuit after the amplifier amplification that voltage passes through INA200 chip interior, comparator generates input voltage and inside
Reference voltage be compared, and comparison result is exported to logic control circuit, the logic control circuit is to power tube
Open or turn off and controlled, the protection period control circuit be used for control protection period size and realize circuit from
It is dynamic to reset.
2. electronics self-recovery fuse circuit according to claim 1, which is characterized in that the current sampling circuit includes
Current signal is converted voltage signal by sample resistance, sample resistance, wherein high voltage is input to 8 feet of INA200 chip, low
Voltage input is to 7 feet.
3. electronics self-recovery fuse circuit according to claim 1, which is characterized in that the logic control circuit includes
Logic gate and level-one NOT gate, the logic gate are connect with power tube and protection period control circuit, and the level-one NOT gate is set to and patrols
It collects between door and 6 feet of INA200 chip.
4. electronics self-recovery fuse circuit according to claim 1, which is characterized in that the delay circuit includes capacitor
The C1 and resistance R1 and resistance R2 being connect with capacitor C1.
5. electronics self-recovery fuse circuit according to claim 1, which is characterized in that the protection period control circuit
Including capacitor C2, the resistance R3 being connect with capacitor C2, resistance R4, and the diode D1 being connect with resistance R4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820517939.9U CN208284987U (en) | 2018-04-12 | 2018-04-12 | Electronics self-recovery fuse circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820517939.9U CN208284987U (en) | 2018-04-12 | 2018-04-12 | Electronics self-recovery fuse circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208284987U true CN208284987U (en) | 2018-12-25 |
Family
ID=64749534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820517939.9U Active CN208284987U (en) | 2018-04-12 | 2018-04-12 | Electronics self-recovery fuse circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111987689A (en) * | 2019-05-22 | 2020-11-24 | 上汽通用汽车有限公司 | Intelligent fuse box and method for monitoring load |
| CN112993933A (en) * | 2021-04-22 | 2021-06-18 | 宜宾听点科技有限公司 | Self-recovery protection circuit and device |
-
2018
- 2018-04-12 CN CN201820517939.9U patent/CN208284987U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111987689A (en) * | 2019-05-22 | 2020-11-24 | 上汽通用汽车有限公司 | Intelligent fuse box and method for monitoring load |
| CN112993933A (en) * | 2021-04-22 | 2021-06-18 | 宜宾听点科技有限公司 | Self-recovery protection circuit and device |
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