CN212969049U - Circuit protection device - Google Patents
Circuit protection device Download PDFInfo
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- CN212969049U CN212969049U CN202020508364.1U CN202020508364U CN212969049U CN 212969049 U CN212969049 U CN 212969049U CN 202020508364 U CN202020508364 U CN 202020508364U CN 212969049 U CN212969049 U CN 212969049U
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Abstract
The utility model discloses a circuit protection device, include: the first end of the first resistor is used for being electrically connected with an external first power supply; the second end of the first resistor is electrically connected with the emitting electrode of the first PNP type triode; the base electrode of the first PNP type triode is electrically connected with the collector electrode of the second PNP type triode, and the collector electrode of the first PNP type triode is used for being electrically connected with a load device for supplying power for an external load; the base electrode of the second PNP type triode is electrically connected with the second end of the first resistor; the emitter of the second PNP type triode is electrically connected with the first end of the first resistor; the first end of the second resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is used for grounding. Use the embodiment of the utility model provides a device accessible configuration different resistances's first resistance satisfies the different current-limiting requirements of external load, and then can provide controllable limiting current.
Description
Technical Field
The utility model relates to a power technical field especially relates to a circuit protection device.
Background
The reliability and the safety of the existing circuits are increasingly pursued, and many circuits need to be provided with an overvoltage and overcurrent detection circuit so as to protect the circuits.
At present, the overcurrent protection of a circuit generally adopts fuse current-limiting protection, and generally, for a self-recovery fuse tube which ensures the safe operation of the circuit, the working principle of the self-recovery fuse tube is as follows: when abnormal large current occurs in the line, the resistance value of the resistor of the line is very large, so that the line can generate high temperature to prevent current from passing through, and when the temperature returns to normal, the resistance value of the resistor of the line is smaller, so that the line conduction is restored. However, the conventional self-recovery fuse tube generally limits the current within a standard fixed range in a step-by-step increasing manner. If the current is limited within the range of 500MA, 1A, 1.5A, 3A and the like at intervals of 500MA, but for some devices which are stricter in current limitation and are not within the standard fixed range, such as devices which require current limitation at 450MA and 320MA, the existing self-recovery fuse cannot meet the requirement, and it can be seen that the current limitation output by the existing self-recovery fuse is not controllable.
SUMMERY OF THE UTILITY MODEL
An object of the embodiment of the utility model is to provide a circuit protection device to controllable limiting current is provided. The specific technical scheme is as follows:
in a first aspect, an embodiment of the present invention provides a circuit protection device, the device includes: the circuit comprises a first resistor, a second resistor, a first PNP type triode and a second PNP type triode;
the first end of the first resistor is used for being electrically connected with an external first power supply; the second end of the first resistor is electrically connected with the emitter of the first PNP type triode;
the base electrode of the first PNP type triode is electrically connected with the collector electrode of the second PNP type triode, and the collector electrode of the first PNP type triode is used for being electrically connected with a load device for supplying power for an external load;
the base electrode of the second PNP type triode is electrically connected with the second end of the first resistor; the emitting electrode of the second PNP type triode is electrically connected with the first end of the first resistor;
the first end of the second resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is used for being grounded.
In an embodiment of the present invention, the apparatus further comprises: a third resistor;
the first end of the third resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the third resistor is electrically connected with the collector electrode of the second PNP type triode.
In an embodiment of the present invention, the apparatus further comprises: a fourth resistor and a first MOSFET;
the first end of the fourth resistor is electrically connected with the collector electrode of the first PNP type triode; a second end of the fourth resistor is electrically connected with the grid electrode of the first MOSFET;
the source of the first MOSFET is used for being electrically connected with a load device for supplying power to an external load, and the drain of the first MOSFET is used for being electrically connected with a second power supply.
In one embodiment of the present invention, the device further comprises a fifth resistor,
the first end of the fifth resistor is electrically connected with the second end of the fourth resistor; and the second end of the fifth resistor is used for grounding.
In an embodiment of the present invention, the apparatus further comprises: a voltage stabilizing capacitor or/and a transient diode TVS;
the first end of the voltage stabilizing capacitor is electrically connected with the first end of the first resistor; the second end of the voltage stabilizing capacitor is used for grounding;
or/and the first end of the TVS is used for being electrically connected with the first power supply and also electrically connected with the first end of the voltage stabilizing capacitor, and the second end of the TVS is used for being grounded.
In an embodiment of the present invention, the apparatus further comprises: a first capacitor and a second capacitor;
the first end of the first capacitor is electrically connected with the second end of the first resistor; the second end of the first capacitor is used for grounding;
the first end of the second capacitor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second capacitor is used for grounding.
In an embodiment of the present invention, the apparatus further comprises: a potentiometer;
the second end of the first resistor is electrically connected with the first pin of the potentiometer, and the second pin of the potentiometer and the movable contact pin of the potentiometer are electrically connected with the base electrode of the second PNP type triode.
In an embodiment of the present invention, the apparatus further comprises: a Schottky diode;
the cathode of the Schottky diode is electrically connected with the first end of the fourth resistor, and the anode of the Schottky diode is electrically connected with the second end of the fourth resistor.
In an embodiment of the present invention, the apparatus further comprises: a first voltage output type sensor and a first analog/digital converter;
the input end of the first voltage output type sensor is electrically connected with the first power supply; the first output end of the first voltage output type sensor is used for grounding, and the second output end of the first voltage output type sensor is electrically connected with the first end of the first resistor;
the collector of the first PNP type triode is electrically connected with the input end of the first analog/digital converter;
and the output end of the first analog/digital converter is electrically connected with an external singlechip.
In a second aspect, an embodiment of the present invention provides a circuit protection device, the device includes: a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a third PNP triode, a first NPN triode, a second NPN triode and a second MOSFET;
the first end of the sixth resistor is used for being electrically connected with an external third power supply; a second end of the sixth resistor is electrically connected with a collector of the first NPN type triode;
a base electrode of the first NPN type triode is electrically connected with a collector electrode of the second NPN type triode and a first end of the seventh resistor respectively, and an emitting electrode of the first NPN type triode is electrically connected with a first end of the ninth resistor;
an emitter of the second NPN type triode is used for grounding, and a base of the second NPN type triode is electrically connected with the first end of the eighth resistor;
a second end of the seventh resistor is used for being electrically connected with the third power supply;
the second end of the eighth resistor is electrically connected with the collector of the third PNP type triode;
the base electrode of the third PNP type triode is electrically connected with the second end of the sixth resistor; an emitting electrode of the third PNP type triode is electrically connected with a first end of the sixth resistor;
a second end of the ninth resistor is electrically connected with a gate of the second MOSFET and a first end of the tenth resistor, respectively;
the source electrode of the second MOSFET is used for being electrically connected with a load device for supplying power to an external load; the drain electrode of the second MOSFET is electrically connected with an external fourth power supply;
the second end of the tenth resistor is used for grounding.
In an embodiment of the present invention, the apparatus further comprises: a second voltage output type sensor and a second analog/digital converter;
the input end of the second voltage output type sensor is used for being electrically connected with the third power supply, the second output end of the second voltage output type sensor is electrically connected with the first end of the sixth resistor, and the second output end of the second voltage output type sensor is used for being grounded;
an emitter of the second NPN type triode is electrically connected with the input end of the second analog/digital converter;
and the output end of the second analog/digital converter is electrically connected with the singlechip.
The embodiment of the utility model provides a circuit protection device, the first end of the first resistance of the device is used for being electrically connected with the first power supply of the outside; the second end of the first resistor is electrically connected with the emitting electrode of the first PNP type triode; the base electrode of the first PNP type triode is electrically connected with the collector electrode of the second PNP type triode, and the collector electrode of the first PNP type triode is used for being electrically connected with a load device for supplying power for an external load; the base electrode of the second PNP type triode is electrically connected with the second end of the first resistor; the emitter of the second PNP type triode is electrically connected with the first end of the first resistor; the first end of the second resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is used for grounding. Compared with the prior art, the embodiment of the utility model provides a device accessible disposes the first resistance of different resistances, satisfies the different current-limiting requirements of external load. Therefore, use the embodiment of the utility model provides a circuit protection device can provide controllable limiting current. Of course, it is not necessary for any product or method of the invention to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 2 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 3 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 4 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 5 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 6 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 7 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 8 is another schematic structural diagram of a circuit protection device according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of another circuit protection device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In order to export low current voltage, the embodiment of the utility model provides a circuit protection device.
As shown in fig. 1, an embodiment of the present invention provides a circuit protection device, which includes an electrical first resistor, a second resistor, a first PNP type triode, and a second PNP type triode;
the first end of the first resistor is used for being electrically connected with an external first power supply VCC (volt Current concentrator); the second end of the first resistor is electrically connected with the emitter of the first PNP type triode;
the base electrode of the first PNP type triode is electrically connected with the collector electrode of the second PNP type triode, and the collector electrode of the first PNP type triode is used for being electrically connected with a load device for supplying power for an external load;
the base electrode of the second PNP type triode is electrically connected with the second end of the first resistor; the emitting electrode of the second PNP type triode is electrically connected with the first end of the first resistor;
the first end of the second resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is used for being connected with GND (Ground).
In the embodiment of the present invention, the first resistor may be an adjustable rheostat, such as a position adjuster. The voltage difference at two ends of the first resistor can be changed by adjusting the resistance value of the first resistor, so that the purpose of limiting the current can be achieved.
The first PNP type transistor and the second PNP type transistor may be the same PNP type transistor or different PNP type transistors, which is not limited in this embodiment.
The PNP transistor is a transistor formed by 2P-type semiconductors and 1N-type semiconductor sandwiched therebetween, and is called a PNP transistor. The PNP type triode has the highest emitter potential and the lowest collector potential.
The base electrode of the first PNP type triode is electrically connected with the second resistor, so that the base electrode of the first PNP type triode is not suspended, and the first PNP type triode can be effectively grounded when the input current of the first PNP type triode is uncertain. That is, the second resistor can prevent the first PNP type triode from generating false operation due to the influence of the noise signal, so that the first PNP type triode is cut off more reliably.
The utility model discloses among the circuit protection device of embodiment, because the voltage threshold of first PNP type triode and second PNP type triode has all been predetermined, then the size of limiting current is by first resistance control, that is to say, first resistance is bigger, then the limiting current is smaller, first resistance is smaller, then the limiting current is bigger, when having strict equipment to the electric current to limit the electric current, can confirm the required current-limiting of this equipment according to formula I ═ U/R, in the above-mentioned formula, I is the current-limiting value, U is the voltage threshold of first PNP type triode and second PNP type triode, R is the resistance of first resistance.
The load device is used for supplying power to a load, one end of the load device is electrically connected with a collector electrode of the first PNP type triode, and the other end of the load device is grounded.
The first power supply may be a current power supply or a voltage power supply, which is not limited in this embodiment.
The working principle of the circuit protection device in the embodiment is as follows: when the current passes through the first resistor, a voltage difference is generated across the first resistor. And the larger the current, the higher the voltage across the first resistor, as determined by the first resistor. If the voltage threshold values of the base electrodes and the emitting electrodes of the first PNP type triode and the second PNP type triode are both 0.7V, when the voltage difference between two ends of the first resistor exceeds 0.7V, the second PNP type triode is conducted, at the moment, the collector current of the second PNP type triode can increase the level of the base electrode of the first PNP type triode, at the moment, the second PNP type triode is cut off, and then the circuit flowing to the external load is cut off. If the current output by the current power supply is within the safety range, when the voltage difference between two ends of the first resistor is not more than 0.7V, the current of the base electrode of the first PNP type triode can be shunted by the second resistor, at the moment, the first PNP type triode is conducted, and the shunted current normally flows to an external load circuit.
Based on the above analysis of the circuit protection device, if the current limiting requirements of the external load are different, the resistance values of the first resistors configured correspondingly are also different.
For example, if the current limiting requirement of the external load is 450MA, the current limiting requirement of 450MA for current limiting may be satisfied when the first resistor configured in the circuit protection device of this embodiment is 24 Ω, and if the current limiting requirement of the external load is 330MA, the current limiting requirement of 330MA for current limiting may be satisfied when the first resistor configured in the circuit protection device of this embodiment is 35 Ω.
Therefore, in the technical solution provided by the embodiment of the present invention, the first end of the first resistor is used for being electrically connected to the first power supply; the second end of the first resistor is electrically connected with the emitting electrode of the first PNP type triode; the base electrode of the first PNP type triode is electrically connected with the collector electrode of the second PNP type triode, and the collector electrode of the first PNP type triode is used for being electrically connected with a load device for supplying power for an external load; the base electrode of the second PNP type triode is electrically connected with the second end of the first resistor; the emitter of the second PNP type triode is electrically connected with the first end of the first resistor; the first end of the second resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is used for grounding. Compared with the prior art, the embodiment of the utility model provides a device accessible disposes the first resistance of different resistances, satisfies the different current-limiting requirements of external load. Therefore, use the embodiment of the utility model provides a circuit protection device can provide controllable limiting current.
In order to protect the low-current load and prevent the current input from the outside from being overlarge and the input source voltage from suddenly increasing, or the input source current generates pulse current to cause the load to burn. As shown in fig. 2, in an embodiment of the present invention, the above apparatus may further include: and a third resistor.
The first end of the third resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is electrically connected with the collector electrode of the second PNP type triode.
The third resistor can shunt the current of the base electrode of the first PNP type triode, namely, the base electrode of the first PNP type triode is pulled up.
The working principle of the embodiment is as follows: when the current passes through the first resistor, a voltage difference is generated across the first resistor. And the larger the current, the higher the voltage across the first resistor, as determined by the first resistor. If the voltage threshold values of the base electrodes and the emitting electrodes of the first PNP type triode and the second PNP type triode are both 0.7V, when the input current is smaller than or equal to the limited current, the voltage difference between the two ends of the first resistor is lower than 0.7V, the second PNP type triode is cut off, at the moment, the level of the base electrode of the first PNP type triode is changed into 0V under the action of the base electrode of the second resistor, the first PNP type triode is conducted, and the current supplies power for the external load through the first PNP type triode. When the input current is larger than the limited current, the voltage difference between two ends of the first resistor is higher than 0.7V, the second PNP type triode is conducted, at the moment, the base electrode of the first PNP type triode is under the action of the third resistor, the level of the base electrode of the first PNP type triode is increased, the first PNP type triode is cut off, and the first PNP type triode is cut off to supply power for the external load.
It can be seen that, in the technical solution provided in this embodiment, the first end of the third resistor is electrically connected to the base of the first PNP type triode, and the second end of the third resistor is electrically connected to the collector of the second PNP type triode, so that the level of the base of the second PNP type triode can be raised under the condition that the input current is greater than the limited current, thereby protecting the low-current load, and meanwhile, the first resistor having a resistance value corresponding to the current-limiting requirement can be configured according to the current-limiting requirement of the load, thereby providing the controllable limited current.
In an embodiment of the present invention, the above device may further include: a fourth resistor and a first MOSFET;
the first end of the fourth resistor is electrically connected with the collector electrode of the first PNP type triode; a second end of the fourth resistor is electrically connected with the grid electrode of the first MOSFET;
the source electrode of the first MOSFET is used for being electrically connected with a load device for supplying power to an external load, and the drain electrode of the first MOSFET is used for being electrically connected with a second power supply VDD (version Description Documen).
The fourth resistor can divide the voltage of the first MOSFET, normally, the gate voltage of the MOSFET is between 10 and 20V, but some low-voltage MOSFETs exist, and the MOSFET is completely turned on when the voltage is more than 2V. The grid voltage of the first MOSFET can be divided into the range of normal work of the first MOSFET through the fourth resistor, so that the circuit can be ensured to work stably, and the effect of voltage stabilization and power supply for the load can be further achieved.
The specific working principle of this embodiment is as follows:
when the voltage source VCC is located within the allowable voltage range, and the collector of the first PNP type triode outputs normal current, the level of the grid of the first MOSFET is raised, the first MOSFET is conducted, and at the moment, the VCC can supply power for an external load through the first MOSFET.
When VCC exceeds the allowable voltage range, at the moment, the current passing through the first resistor is too large, the first PNP type triode is cut off, and meanwhile, the first MOSFET is cut off, and at the moment, VCC stops supplying power for the external load.
Therefore, in the technical solution provided by the embodiment of the present invention, the first end of the fourth resistor is electrically connected to the collector electrode of the first PNP type triode; a second end of the fourth resistor is electrically connected with the grid electrode of the first MOSFET; the source of the first MOSFET is adapted to be electrically connected to a load device for supplying power to an external load, and the drain of the first MOSFET is adapted to be grounded. Therefore, the fourth resistor can divide voltage for the grid electrode of the first MOSFET, the first MOSFET can work within a normal range, and the first MOSFET can be used for stabilizing voltage for an external load.
In an embodiment of the present invention, as shown in fig. 3, the above apparatus may further include: a fifth resistance, which is a resistance of the second resistor,
the first end of the fifth resistor is electrically connected with the second end of the fourth resistor; and the second end of the fifth resistor is used for grounding.
Under the condition that the voltage in the circuit is too large, the fifth resistor can divide the voltage of the grid electrode of the first MOSFET so as to ensure that the circuit can work stably.
The specific working principle of this embodiment is as follows:
when the voltage source VCC is located within the allowable voltage range, and the collector of the first PNP type triode outputs normal current, the level of the grid of the first MOSFET is raised, the first MOSFET is conducted, and at the moment, the VCC can supply power for an external load through the first MOSFET.
When VCC exceeds the allowable voltage range, at the moment, the current passing through the first resistor is too large, the first PNP type triode is cut off, the grid electrode of the first MOSFET is under the action of the fifth resistor, the level is 0, the first MOSFET is cut off, and at the moment, VCC stops supplying power for the external load.
It can be seen that the first end of the fifth resistor of this embodiment is electrically connected to the second end of the fourth resistor, and the second end of the fifth resistor is used for grounding, so as to further divide the voltage for the gate of the first MOSFET, so that the circuit can operate in a voltage-stabilized state, thereby providing a stable voltage for an external load, and performing an overvoltage protection function.
In the case that the input power source may have instability and an electrostatic field, as shown in fig. 3 and 4, in an embodiment of the present invention, the apparatus may further include: a Voltage regulator capacitor, or/and, a TVS (Transient Voltage super);
the first end of the voltage stabilizing capacitor is electrically connected with the first end of the first resistor; the second end of the voltage stabilizing capacitor is used for grounding;
and/or the first and/or second light sources,
the first end of the TVS is used for being electrically connected with a first power supply and also electrically connected with the first end of the voltage stabilizing capacitor, and the second end of the TVS is used for being grounded.
Because some input power supplies with overlarge ripples and high pulse voltage exist, the TVS provided by the embodiment can play a role in discharging pulse current and protecting the following circuit devices from breakdown.
And the setting of voltage-stabilizing capacitor can play the effect of stored energy, and promptly, when the input power ripple is great, the energy of voltage-stabilizing capacitor storage just can compensate the power fluctuation, ensures the voltage stabilization on the first resistance.
It can be seen that, in the technical solution provided in this embodiment, the first end of the voltage stabilizing capacitor is electrically connected to the first end of the first resistor; the second end of the voltage stabilizing capacitor is used for grounding; or/and the first end of the TVS is used for being electrically connected with a first power supply and also electrically connected with the first end of the voltage-stabilizing capacitor, and the second end of the TVS is used for being grounded. The circuit device in the TVS back-end circuit can be protected from being damaged, the stability of the first resistance voltage can be ensured, and pulse high voltage and noise on a power supply can be prevented from appearing on the input power supply.
In an embodiment of the present invention, as shown in fig. 5, the above apparatus may further include: a first capacitor and a second capacitor;
the first end of the first capacitor is electrically connected with the second end of the first resistor; the second end of the first capacitor is used for grounding;
the first end of the second capacitor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second capacitor is used for grounding.
As can be seen from fig. 5, the first capacitor is electrically connected to the base of the second PNP transistor, so as to prevent the second PNP transistor from being continuously turned on or off when the current reaches the current threshold of the base of the second PNP transistor.
Similarly, the second capacitor is electrically connected to the base of the first PNP transistor, thereby preventing the first PNP transistor from being continuously turned on or off when the current reaches the current threshold of the base of the first PNP transistor.
Therefore, in an embodiment of the present invention, a first end of the first capacitor is electrically connected to a second end of the first resistor; the second end of the first capacitor is used for grounding; the first end of the second capacitor is electrically connected with the base electrode of the first PNP type triode, the second end of the second capacitor is used for being grounded, and the first capacitor and the second capacitor are arranged to protect the first PNP type triode and the second PNP type triode from being continuously switched on and off, so that the first PNP type triode and the second PNP type triode are protected.
In an embodiment of the present invention, as shown in fig. 6, the above apparatus may further include: a potentiometer;
the second end of the first resistor is electrically connected with the first pin of the potentiometer, and the second pin of the potentiometer and the movable contact pin of the potentiometer are electrically connected with the base electrode of the second PNP type triode.
In this embodiment, the first resistor can bear a maximum current value that can be limited by the circuit protection device of this embodiment, and the first resistor is used to prevent the first PNP type triode from being damaged due to too large current when the resistance value adjusted by the potentiometer is 0.
If the current-limiting requirements of different loads are to be met, the resistance value of the potentiometer can be adjusted, so that the output current can meet the current-limiting requirement of an external load.
It is thus clear that the embodiment of the utility model provides an among the technical scheme, the second end of above-mentioned first resistance is connected with the first pin electricity of potentiometre, and the second pin of above-mentioned potentiometre and the movable contact foot of above-mentioned potentiometre all are connected with the base electricity of above-mentioned second PNP type triode, and the potentiometre set up to make protection circuit device satisfy various external load's current-limiting requirement, and then reach and to provide controllable limiting current purpose.
In an embodiment of the present invention, as shown in fig. 7, the above apparatus may further include: a Schottky diode;
the cathode of the Schottky diode is electrically connected with the first end of the fourth resistor, and the anode of the Schottky diode is electrically connected with the second end of the fourth resistor.
Among them, the schottky diode has the advantages of high switching frequency and reduced forward voltage, but its reverse breakdown voltage is relatively low, mostly not higher than 60V, and only about 100V at most, so as to limit its application range.
In this embodiment, the combination of the schottky diode and the fourth resistor may form a bleeding circuit, so that when the front-end circuit before the schottky diode is in a protection state, the current of the back-end circuit after the schottky diode may be bled quickly, and the whole circuit protection device may have a function of opening and closing quickly.
It can be seen that the cathode of the schottky diode of this embodiment is electrically connected to the first end of the fourth resistor, and the anode of the schottky diode is electrically connected to the second end of the fourth resistor, so that the whole circuit protection device has a function of fast opening and closing, thereby achieving the purpose of fast protecting an external load and also improving the power supply efficiency of the external load.
In view of the wide output voltage range of the voltage type sensor, in an embodiment of the present invention, as shown in fig. 8, the apparatus may further include: a first voltage output type sensor and a first analog/digital converter;
the input end of the first voltage output type sensor is electrically connected with a first power supply; the first output end of the first voltage output type sensor is used for grounding, and the second output end of the first voltage output type sensor is electrically connected with the first end of the first resistor;
the collector of the first PNP type triode is electrically connected with the input end of the first analog/digital converter;
and the output end of the first analog/digital converter is electrically connected with an external singlechip.
In this embodiment, the first voltage output type sensor can filter out an excessively high voltage, so that the second end of the first voltage output type sensor outputs a relatively stable voltage.
Therefore, in the technical solution provided by the embodiment of the present invention, the input end of the first voltage output type sensor is used for being electrically connected with the first power supply; the first output end of the first voltage output type sensor is used for grounding, and the second output end of the first voltage output type sensor is electrically connected with the first end of the first resistor; the collector of the first PNP type triode is electrically connected with the input end of the first analog/digital converter; first analog/digital converter's output is used for being outside single chip microcomputer electricity to be connected, can filter the too high voltage, and then can protect this embodiment circuit protection device and external load, it is visible, use the embodiment of the utility model provides a technical scheme not only can provide controllable limiting circuit, can also provide stable voltage.
Referring to fig. 9, fig. 9 is a schematic structural diagram of a circuit protection device according to an embodiment of the present invention, where the circuit protection device includes: the first PNP triode is connected with the first resistor, the second resistor, the third resistor, the seventh resistor, the eighth resistor, the ninth resistor, the tenth resistor, the third NPN triode, the first NPN triode, the second NPN triode and the second MOSFET;
the first end of the sixth resistor is used for being electrically connected with an external third power supply; a second end of the sixth resistor is electrically connected with a collector of the first NPN type triode;
a base electrode of the first NPN type triode is electrically connected with a collector electrode of the second NPN type triode and a first end of the seventh resistor respectively, and an emitting electrode of the first NPN type triode is electrically connected with a first end of the ninth resistor;
an emitter of the second NPN type triode is used for grounding, and a base of the second NPN type triode is electrically connected with the first end of the eighth resistor;
a second end of the seventh resistor is used for being electrically connected with the third power supply;
the second end of the eighth resistor is electrically connected with the collector of the third PNP type triode;
the base electrode of the third PNP type triode is electrically connected with the second end of the sixth resistor; an emitting electrode of the third PNP type triode is electrically connected with a first end of the sixth resistor;
a second end of the ninth resistor is electrically connected with a gate of the second MOSFET and a first end of the tenth resistor, respectively;
the source electrode of the second MOSFET is used for being electrically connected with a load device for supplying power to an external load; the drain electrode of the second MOSFET is electrically connected with an external fourth power supply;
the second end of the tenth resistor is used for grounding.
In this embodiment, the sixth resistor may be an adjustable varistor, such as a position adjuster. The voltage difference between the two ends of the sixth resistor can be changed by adjusting the resistance value of the sixth resistor, so that the purpose of current limiting can be achieved.
The third power supply and the fourth power supply may be the same power supply or different power supplies, and meanwhile, the third power supply and the fourth power supply may be the same as the first power supply or different from the first power supply, and correspondingly, the third power supply and the fourth power supply may also be the same as the second power supply or different from the second power supply, which is not limited in this embodiment.
The utility model provides an among the circuit protection device, because the voltage threshold of first NPN type triode, second NPN type triode and third PNP type triode has all been predetermined, then the size of limiting current is by sixth resistance control, that is to say, sixth resistance is bigger, then the limiting current is less, sixth resistance is less, then the limiting current is bigger, when having strict equipment to the electric current to limit the current, can determine the required current-limiting of this equipment according to formula I ═ U/R, in the above-mentioned formula, I is the current-limiting value, U is the voltage threshold of first NPN type triode, second NPN type triode and third PNP type triode, R is the resistance of sixth resistance.
A first end of the ninth resistor is electrically connected with an emitting electrode of the first NPN type triode; a second end of the ninth resistor is electrically connected with the grid electrode of the second MOSFET; the ninth resistor can divide the voltage of the second MOSFET, normally, the gate voltage of the MOSFET is between 10 and 20V, but some low-voltage MOSFETs exist, and the second MOSFET is completely turned on when the voltage is more than 2V. The grid voltage of the second MOSFET can be divided into the range of normal work of the second MOSFET through the tenth resistor, so that the circuit can be ensured to work stably, and the effect of voltage stabilization and power supply for the load can be further achieved.
The working principle of the circuit protection device in the embodiment is as follows: when the current passes through the sixth resistor, a voltage difference is generated between the two ends of the sixth resistor. And when the sixth resistor is determined, the larger the current, the higher the voltage between both ends of the sixth resistor. The voltage threshold values of the base electrode and the emitting electrode of the third PNP type triode are both 0.7V, if the current output by the third power supply is in the normal range, and the voltage difference between the base electrode and the emitting electrode of the third PNP type triode is not more than 0.7V, the third PNP type triode is not conducted, the second NPN type triode is not conducted, meanwhile, the level of the base electrode of the first NPN type triode is increased under the action of the seventh resistor, the first NPN type triode is conducted, and the circuit protection device normally supplies power for the load. If the current output by the third power supply is too large, and the voltage difference between the base electrode and the emitting electrode of the third PNP type triode exceeds 0.7V, the third PNP type triode is conducted, the level of the base electrode of the second NPN type triode is increased, the second NPN type triode is conducted, meanwhile, the level of the base electrode of the first NPN type triode is reduced to 0, the first NPN type triode is different, and at the moment, the protection circuit is disconnected and cannot supply power to the load.
Based on the above analysis of the circuit protection device, if the current limiting requirements of the external load are different, the resistance values of the sixth resistors configured correspondingly are also different.
For example, if the current limiting requirement of the external load is 420MA, the current limiting requirement of 420MA for current limiting may be satisfied when the sixth resistor configured in the circuit protection device of this embodiment is 20 Ω, and if the current limiting requirement of the external load is 380MA, the current limiting requirement of 380MA for current limiting may be satisfied when the sixth resistor configured in the circuit protection device of this embodiment is 15 Ω.
Therefore, in the technical solution provided in the embodiment of the present invention, the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, the tenth resistor, the third PNP type triode, the first NPN type triode, the second NPN type triode, and the second MOSFET; the first end of the sixth resistor is used for being electrically connected with an external third power supply; a second end of the sixth resistor is electrically connected with a collector of the first NPN type triode; a base electrode of the first NPN type triode is electrically connected with a collector electrode of the second NPN type triode and a first end of the seventh resistor respectively, and an emitting electrode of the first NPN type triode is electrically connected with a first end of the ninth resistor; an emitter of the second NPN type triode is used for being grounded, and a base of the second NPN type triode is electrically connected with the first end of the eighth resistor; the second end of the seventh resistor is used for being electrically connected with a third power supply; the second end of the eighth resistor is electrically connected with the collector electrode of the third PNP type triode; the base electrode of the third PNP type triode is electrically connected with the second end of the sixth resistor; an emitting electrode of the third PNP type triode is electrically connected with the first end of the sixth resistor; a second end of the ninth resistor is electrically connected with a grid electrode of the second MOSFET and a first end of the tenth resistor respectively; the source electrode of the second MOSFET is used for being electrically connected with a load device for supplying power to an external load; the drain electrode of the second MOSFET is electrically connected with an external fourth power supply; the second end of the tenth resistor is used for grounding. Compared with the prior art, the embodiment of the utility model provides a device accessible disposes the sixth resistance of different resistances, satisfies the different current-limiting requirements of external load. Meanwhile, the level of the base electrode of the first NPN type triode can be quickly reduced to 0 by utilizing the second NPN type triode, and the purpose of timely protecting the overcurrent of the circuit is further achieved. Therefore, use the embodiment of the utility model provides a circuit protection device can provide controllable limiting current, and protection circuit's ageing is high.
In an embodiment of the present invention, the above device may further include: a second voltage output type sensor and a second analog/digital converter;
the input end of the second voltage output type sensor is used for being electrically connected with the third power supply, the second output end of the second voltage output type sensor is electrically connected with the first end of the sixth resistor, and the second output end of the second voltage output type sensor is used for being grounded;
an emitter of the second NPN type triode is electrically connected with the input end of the second analog/digital converter;
and the output end of the second analog/digital converter is electrically connected with the singlechip.
In this embodiment, the second voltage output type sensor can filter out the excessive voltage, so that the second end of the second voltage output type sensor outputs a relatively stable voltage.
It can be seen that in the technical solutions provided in the embodiments of the present invention, the second voltage output type sensor and the second analog/digital converter; the input end of the second voltage output type sensor is used for being electrically connected with the third power supply, the second output end of the second voltage output type sensor is electrically connected with the first end of the sixth resistor, and the second output end of the second voltage output type sensor is used for being grounded; the emitter of the second NPN type triode is electrically connected with the input end of the second analog/digital converter; the output of second analog/digital converter is used for being connected with the monolithic is electromechanical, can filter the too high voltage, and then can protect this embodiment circuit protection device and external load, it is visible, use the embodiment of the utility model provides a technical scheme not only can provide controllable limiting circuit, can also provide stable voltage.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a device that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such device. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of additional like elements in the device.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (11)
1. A circuit protection device, the device comprising: the circuit comprises a first resistor, a second resistor, a first PNP type triode and a second PNP type triode;
the first end of the first resistor is used for being electrically connected with an external first power supply; the second end of the first resistor is electrically connected with the emitter of the first PNP type triode;
the base electrode of the first PNP type triode is electrically connected with the collector electrode of the second PNP type triode, and the collector electrode of the first PNP type triode is used for being electrically connected with a load device for supplying power for an external load;
the base electrode of the second PNP type triode is electrically connected with the second end of the first resistor; the emitting electrode of the second PNP type triode is electrically connected with the first end of the first resistor;
the first end of the second resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second resistor is used for being grounded.
2. The apparatus of claim 1, further comprising: a third resistor;
the first end of the third resistor is electrically connected with the base electrode of the first PNP type triode, and the second end of the third resistor is electrically connected with the collector electrode of the second PNP type triode.
3. The apparatus of claim 2, further comprising: a fourth resistor and a first MOSFET;
the first end of the fourth resistor is electrically connected with the collector electrode of the first PNP type triode;
a second end of the fourth resistor is electrically connected with the grid electrode of the first MOSFET;
the source electrode of the first MOSFET is used for being electrically connected with a load device for supplying power to an external load, and the drain electrode of the first MOSFET is used for being electrically connected with an external second power supply.
4. The apparatus of claim 3, further comprising a fifth resistor,
the first end of the fifth resistor is electrically connected with the second end of the fourth resistor; and the second end of the fifth resistor is used for grounding.
5. The apparatus of any one of claims 1-4, further comprising: a voltage stabilizing capacitor or/and a transient diode TVS;
the first end of the voltage stabilizing capacitor is electrically connected with the first end of the first resistor; the second end of the voltage stabilizing capacitor is used for grounding;
or/and the first end of the TVS is used for being electrically connected with the first power supply and also electrically connected with the first end of the voltage stabilizing capacitor, and the second end of the TVS is used for being grounded.
6. The apparatus of any one of claims 2-4, further comprising: a first capacitor and a second capacitor;
the first end of the first capacitor is electrically connected with the second end of the first resistor; the second end of the first capacitor is used for grounding;
the first end of the second capacitor is electrically connected with the base electrode of the first PNP type triode, and the second end of the second capacitor is used for grounding.
7. The apparatus of claim 1 or 2, further comprising: a potentiometer;
the second end of the first resistor is electrically connected with the first pin of the potentiometer, and the second pin of the potentiometer and the movable contact pin of the potentiometer are electrically connected with the base electrode of the second PNP type triode.
8. The apparatus of claim 4, further comprising: a Schottky diode;
the cathode of the Schottky diode is electrically connected with the first end of the fourth resistor, and the anode of the Schottky diode is electrically connected with the second end of the fourth resistor.
9. The apparatus of claim 2, further comprising: a first voltage output type sensor and a first analog/digital converter;
the input end of the first voltage output type sensor is electrically connected with the first power supply; the first output end of the first voltage output type sensor is used for grounding, and the second output end of the first voltage output type sensor is electrically connected with the first end of the first resistor;
the collector of the first PNP type triode is electrically connected with the input end of the first analog/digital converter;
and the output end of the first analog/digital converter is electrically connected with an external singlechip.
10. A circuit protection device, the device comprising: a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a third PNP triode, a first NPN triode, a second NPN triode and a second MOSFET;
the first end of the sixth resistor is used for being electrically connected with an external third power supply; a second end of the sixth resistor is electrically connected with a collector of the first NPN type triode;
a base electrode of the first NPN type triode is electrically connected with a collector electrode of the second NPN type triode and a first end of the seventh resistor respectively, and an emitting electrode of the first NPN type triode is electrically connected with a first end of the ninth resistor;
an emitter of the second NPN type triode is used for grounding, and a base of the second NPN type triode is electrically connected with the first end of the eighth resistor;
a second end of the seventh resistor is used for being electrically connected with the third power supply;
the second end of the eighth resistor is electrically connected with the collector of the third PNP type triode;
the base electrode of the third PNP type triode is electrically connected with the second end of the sixth resistor; an emitting electrode of the third PNP type triode is electrically connected with a first end of the sixth resistor;
a second end of the ninth resistor is electrically connected with a gate of the second MOSFET and a first end of the tenth resistor, respectively;
the source electrode of the second MOSFET is used for being electrically connected with a load device for supplying power to an external load; the drain electrode of the second MOSFET is electrically connected with an external fourth power supply;
the second end of the tenth resistor is used for grounding.
11. The apparatus of claim 10, further comprising: a second voltage output type sensor and a second analog/digital converter;
the input end of the second voltage output type sensor is used for being electrically connected with the third power supply, the second output end of the second voltage output type sensor is electrically connected with the first end of the sixth resistor, and the second output end of the second voltage output type sensor is used for being grounded;
an emitter of the second NPN type triode is electrically connected with the input end of the second analog/digital converter;
and the output end of the second analog/digital converter is electrically connected with the singlechip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020508364.1U CN212969049U (en) | 2020-04-09 | 2020-04-09 | Circuit protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020508364.1U CN212969049U (en) | 2020-04-09 | 2020-04-09 | Circuit protection device |
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| Publication Number | Publication Date |
|---|---|
| CN212969049U true CN212969049U (en) | 2021-04-13 |
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| CN202020508364.1U Active CN212969049U (en) | 2020-04-09 | 2020-04-09 | Circuit protection device |
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| CN (1) | CN212969049U (en) |
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