CN212435341U - Overcurrent protection circuit - Google Patents
Overcurrent protection circuit Download PDFInfo
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- CN212435341U CN212435341U CN202020831990.4U CN202020831990U CN212435341U CN 212435341 U CN212435341 U CN 212435341U CN 202020831990 U CN202020831990 U CN 202020831990U CN 212435341 U CN212435341 U CN 212435341U
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Abstract
The application discloses overcurrent protection circuit, this overcurrent protection circuit includes first triode, the second triode, MOS pipe and first resistance, the control end as overcurrent protection circuit through the base of first triode is connected with drive power supply electricity, the collecting electrode of first triode is connected with the grid electricity of MOS pipe, the source electrode of MOS pipe is connected with the one end electricity of first resistance, the other end and the external power supply electricity of first resistance are connected, the drain electrode of MOS pipe is applicable to the electricity and connects external load as overcurrent protection circuit's output, the projecting pole of second triode is connected with the other end electricity of first resistance, the base of second triode is connected with the source electrode electricity of MOS pipe, the collecting electrode of second triode is connected with the grid electricity of MOS pipe. Thus, the overcurrent protection can be realized only by using common triode and other components. The circuit can be applied to a low-power circuit, and has the advantages of high reliability, low cost, automatic recovery and small occupied area of a PCB.
Description
Technical Field
The present disclosure relates to the field of circuit protection, and more particularly, to an overcurrent protection circuit.
Background
The circuit overcurrent and overvoltage protection (circuit overcurrent and overvoltage protection) is used for preventing the main circuit from being damaged by overlarge current caused by short circuit of the main circuit or ring fire of a direct current traction motor, and electric equipment such as a synchronous traction generator, a main rectifier cabinet and the like, and a locomotive protects the overcurrent and overvoltage of the main circuit under the working conditions of traction, resistance braking or self-load.
The traditional current limiting circuit at least needs to use an expensive operational amplifier or a comparator, a precision resistor and other electronic components to be matched with single chip microcomputer software for limiting.
Disclosure of Invention
In view of this, the present disclosure provides an overcurrent protection circuit, including a first transistor, a second transistor, a MOS transistor, and a first resistor;
the base electrode of the first triode is used as the control end of the overcurrent protection circuit and is electrically connected with a driving power supply;
the emitter of the first triode is electrically connected with a grounding end;
the collector electrode of the first triode is electrically connected with the grid electrode of the MOS tube;
the source electrode of the MOS tube is electrically connected with one end of the first resistor;
the other end of the first resistor is used as an input end of the overcurrent protection circuit and is suitable for being electrically connected with an external power supply;
the drain electrode of the MOS tube is used as the output end of the overcurrent protection circuit and is suitable for being electrically connected with an external load;
the emitter of the second triode is electrically connected with the other end of the first resistor;
the base electrode of the second triode is electrically connected with the source electrode of the MOS tube;
and the collector electrode of the second triode is electrically connected with the grid electrode of the MOS tube.
In a possible implementation manner, the device further comprises a voltage stabilizing diode;
the anode of the voltage stabilizing diode is electrically connected with the drain electrode of the MOS tube;
the cathode of the voltage stabilizing diode is used as the output end of the overcurrent protection circuit and is suitable for being electrically connected with an external load.
In a possible implementation manner, the device further comprises a second resistor and a third resistor;
the second resistor and the third resistor are connected between the cathode of the voltage stabilizing diode and the external load in parallel;
the model of the voltage stabilizing diode is 1N5819 HW-7-F.
In a possible implementation manner, the device further comprises a first diode and a second diode;
the first diode and the second diode are connected in parallel between the collector of the second triode and the grid of the MOS tube;
the anode of the first diode is electrically connected with the collector of the second triode;
and the anode of the second diode is electrically connected with the collector of the second triode.
In a possible implementation manner, the circuit further comprises a fourth resistor and a fifth resistor;
one end of the fourth resistor is electrically connected with the grid electrode of the MOS tube;
the other end of the fourth resistor is electrically connected with an emitting electrode of the second triode;
one end of the fifth resistor is electrically connected with the grid electrode of the MOS tube;
the other end of the fifth resistor is electrically connected with the collector of the first triode.
In a possible implementation manner, a sixth resistor is further included;
one end of the sixth resistor is used as a control end of the overcurrent protection circuit and is electrically connected with a driving power supply;
the other end of the sixth resistor is electrically connected with the base electrode of the first triode.
In a possible implementation manner, a seventh resistor is further included;
one end of the seventh resistor is electrically connected with the base electrode of the second triode;
the other end of the seventh resistor is electrically connected with the source electrode of the MOS tube.
In one possible implementation, the voltage of the driving power supply is 24V.
In one possible implementation, the first triode is model BC 847W;
the model of the second triode is BC 857W;
the MOS tube is FQB22P10 TM.
In one possible implementation, the first diode is of the type BAV70WT 1G;
the type of the second diode is the same as that of the first diode.
The base electrode of the first triode is electrically connected with a driving power supply as the control end of the overcurrent protection circuit, the emitting electrode of the first triode is electrically connected with the grounding end, the collecting electrode of the first triode is electrically connected with the grid electrode of the MOS tube, the source electrode of the MOS tube is electrically connected with one end of the first resistor, the other end of the first resistor is electrically connected with an external power supply as the input end of the overcurrent protection circuit, the drain electrode of the MOS tube is electrically connected with an external load as the output end of the overcurrent protection circuit, the emitting electrode of the second triode is electrically connected with the other end of the first resistor, the base electrode of the second triode is electrically connected with the source electrode of the MOS tube, and the collecting electrode of the second triode. Thus, the overcurrent protection can be realized only by using common triode and other components. The circuit can be applied to a low-power circuit, and has the advantages of high reliability, low cost, automatic recovery and small occupied area of a PCB.
Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.
Fig. 1 shows a circuit schematic of an overcurrent protection circuit of an embodiment of the disclosure.
Detailed Description
Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention or for simplicity in description, and do not indicate or imply that the device or element so indicated must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered as limiting the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.
The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present disclosure may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present disclosure.
Fig. 1 shows a circuit schematic of an overcurrent protection circuit 100 according to an embodiment of the disclosure. As shown in fig. 1, the overcurrent protection circuit 100 includes:
comprises a first triode Q5, a second triode Q1, the overcurrent protection circuit comprises a MOS tube Q2 and a first resistor R2, the base of a first triode Q5 is used as the control end of the overcurrent protection circuit 100 and is electrically connected with a driving power supply (24V _ Enable), the emitter of the first triode Q5 is electrically connected with the grounding end, the collector of the first triode Q5 is electrically connected with the gate of the MOS tube Q2, the source of the MOS tube Q2 is electrically connected with one end of a first resistor R2, the other end of the first resistor R2 is used as the input end of the overcurrent protection circuit 100 and is suitable for being electrically connected with an external power supply (+24V), the drain of the MOS tube Q2 is used as the output end of the overcurrent protection circuit 100 and is suitable for being electrically connected with an external load, the emitter of a second triode Q1 is electrically connected with the other end of the first resistor R2, the base of the second triode Q1 is electrically connected with the source of the MOS tube Q2, and the collector of the second.
The base of the first triode Q5 is used as the control terminal of the overcurrent protection circuit 100 and is electrically connected with the driving power supply (24V _ Enable), the emitter of the first triode Q5 is electrically connected with the ground terminal, the collector of the first triode Q5 is electrically connected with the gate of the MOS transistor Q2, the source of the MOS transistor Q2 is electrically connected with one end of the first resistor R2, the other end of the first resistor R2 is used as the input terminal of the overcurrent protection circuit 100 and is adapted to be electrically connected with the external power supply (+24V), the drain of the MOS transistor Q2 is used as the output terminal of the overcurrent protection circuit 100 and is adapted to be electrically connected with the external load, the emitter of the second triode Q1 is electrically connected with the other end of the first resistor R2, the base of the second triode Q1 is electrically connected with the source of the MOS transistor Q2, and the collector of the second triode Q1 is electrically connected with. Thus, the overcurrent protection can be realized only by using common triode and other components. The circuit can be applied to a low-power circuit, and has the advantages of high reliability, low cost, automatic recovery and small occupied area of a PCB.
Specifically, referring to fig. 1, in a possible implementation manner, the overcurrent protection circuit 100 of the present disclosure further includes a zener diode D4, an anode of the zener diode D4 is electrically connected to the drain of the MOS transistor Q2, and a cathode of the zener diode D4 is used as an output terminal of the overcurrent protection circuit 100 and is adapted to be electrically connected to an external load. Preferably, the model of the voltage stabilizing diode D4 can be 1N5819 HW-7-F.
Further, referring to fig. 1, in a possible implementation manner, the overcurrent protection circuit 100 of the present disclosure further includes a second resistor R15 and a third resistor R16, where the second resistor R15 and the third resistor R16 are connected in parallel between the negative electrode of the zener diode D4 and the external load, and preferably, the second resistor R15 has a resistance value of 10R, and the third resistor R16 also has a resistance value of 10R.
Further, referring to fig. 1, in a possible implementation manner, the overcurrent protection circuit 100 of the present disclosure further includes a first diode D3 and a second diode, the first diode D3 and the second diode are connected in parallel between the collector of the second transistor Q1 and the gate of the MOS transistor Q2, the anode of the first diode D3 is electrically connected to the collector of the second transistor Q1, and the anode of the second diode is electrically connected to the collector of the second transistor Q1. Preferably, the first diode D3 may be of the BAV70WT1G, and the second diode may be of the same type as the first diode D3.
Further, referring to fig. 1, in a possible implementation manner, the overcurrent protection circuit 100 of the present disclosure further includes a fourth resistor R5 and a fifth resistor R9, one end of the fourth resistor R5 is electrically connected to the gate of the MOS transistor Q2, the other end of the fourth resistor R5 is electrically connected to the emitter of the second transistor Q1, one end of the fifth resistor R9 is electrically connected to the gate of the MOS transistor Q2, and the other end of the fifth resistor R9 is electrically connected to the collector of the first transistor Q5. Preferably, the fourth resistor R5 may have a resistance of 4.99kR, and similarly, the fifth resistor R9 may have a resistance of 4.99 kR.
Further, referring to fig. 1, in a possible implementation manner, the overcurrent protection circuit 100 of the present disclosure further includes a sixth resistor R13, one end of the sixth resistor R13 is electrically connected to the driving power supply (24V _ Enable) as a control end of the overcurrent protection circuit 100, and the other end of the sixth resistor R13 is electrically connected to the base of the first transistor Q5. Preferably, the resistance of the sixth resistor R13 may be 4.99 kR.
Further, referring to fig. 1, in a possible implementation manner, the overcurrent protection circuit 100 of the present disclosure further includes a seventh resistor R12, one end of the seventh resistor R12 is electrically connected to the base of the second transistor Q1, and the other end of the seventh resistor R12 is electrically connected to the source of the MOS transistor Q2. Preferably, the resistance of the seventh resistor R12 may be 1 kR.
In addition, in the embodiment of the present disclosure, the voltage of the driving power supply (24V _ Enable) is 24V, and the voltage of the external power supply (+24V) is also 24V. Preferably, the first transistor Q5 may be of the type BC847W, the second transistor Q1 may be of the type BC857W, and the MOS transistor Q2 may be of the type FQB22P10 TM.
It is further noted that, referring to fig. 1, the operation principle of the overcurrent protection circuit 100 of the present disclosure is: when the driving power supply (24V _ Enable) signal arrives and the overcurrent protection circuit 100 of the present disclosure operates normally, the external power supply (+24V) generates a voltage drop across the first resistor R2 through the first resistor R2, but the voltage drop is not enough to reach the voltage drop of the second transistor Q1(PNP) Vbe, and the overcurrent protection circuit 100 of the present disclosure does not protect. When an external power supply (+24V) is gradually increased to generate a voltage drop on the first resistor R2 to reach a voltage drop of a second triode Q1(PNP) Vbe, the second triode Q1 is turned on, a voltage difference between a G (gate) terminal and an S (source) terminal of a MOSFET (i.e., a MOS transistor Q2) is about 0.3V +0.7V to 1V, which is lower than a rated minimum turn-on voltage of the MOSFET, the MOS transistor Q2 is turned off to achieve the purpose of overcurrent protection, and when a current drops to a normal range, the second triode Q1 is automatically turned off, and the MOS transistor Q2 is automatically turned on.
It should be noted that, although the overcurrent protection circuit 100 of the present disclosure has been described above by taking the above embodiments as examples, those skilled in the art will understand that the present disclosure should not be limited thereto. In fact, the user can flexibly set the overcurrent protection circuit 100 according to personal preference and/or practical application scenarios as long as the desired functions are achieved.
In this way, the base of the first transistor Q5 is electrically connected to the driving power supply (24V _ Enable) as the control terminal of the overcurrent protection circuit 100, the emitter of the first transistor Q5 is electrically connected to the ground terminal, the collector of the first transistor Q5 is electrically connected to the gate of the MOS transistor Q2, the source of the MOS transistor Q2 is electrically connected to one end of the first resistor R2, the other end of the first resistor R2 is electrically connected to the external power supply (+24V) as the input terminal of the overcurrent protection circuit 100, the drain of the MOS transistor Q2 is electrically connected to the external load as the output terminal of the overcurrent protection circuit 100, the emitter of the second transistor Q1 is electrically connected to the other end of the first resistor R2, the base of the second transistor Q1 is electrically connected to the source of the MOS transistor Q2, and the collector of the second transistor Q1 is electrically connected to the gate of the MOS transistor Q2. Thus, the overcurrent protection can be realized only by using common triode and other components. The circuit can be applied to a low-power circuit, and has the advantages of high reliability, low cost, automatic recovery and small occupied area of a PCB.
Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (10)
1. An overcurrent protection circuit is characterized by comprising a first triode, a second triode, an MOS tube and a first resistor;
the base electrode of the first triode is used as the control end of the overcurrent protection circuit and is electrically connected with a driving power supply;
the emitter of the first triode is electrically connected with a grounding end;
the collector electrode of the first triode is electrically connected with the grid electrode of the MOS tube;
the source electrode of the MOS tube is electrically connected with one end of the first resistor;
the other end of the first resistor is used as an input end of the overcurrent protection circuit and is suitable for being electrically connected with an external power supply;
the drain electrode of the MOS tube is used as the output end of the overcurrent protection circuit and is suitable for being electrically connected with an external load;
the emitter of the second triode is electrically connected with the other end of the first resistor;
the base electrode of the second triode is electrically connected with the source electrode of the MOS tube;
and the collector electrode of the second triode is electrically connected with the grid electrode of the MOS tube.
2. The overcurrent protection circuit of claim 1, further comprising a zener diode;
the anode of the voltage stabilizing diode is electrically connected with the drain electrode of the MOS tube;
the cathode of the voltage stabilizing diode is used as the output end of the overcurrent protection circuit and is suitable for being electrically connected with an external load.
3. The overcurrent protection circuit of claim 2, further comprising a second resistor and a third resistor;
the second resistor and the third resistor are connected between the cathode of the voltage stabilizing diode and the external load in parallel;
the model of the voltage stabilizing diode is 1N5819 HW-7-F.
4. The overcurrent protection circuit of claim 1, further comprising a first diode and a second diode;
the first diode and the second diode are connected in parallel between the collector of the second triode and the grid of the MOS tube;
the anode of the first diode is electrically connected with the collector of the second triode;
and the anode of the second diode is electrically connected with the collector of the second triode.
5. The overcurrent protection circuit of claim 1, further comprising a fourth resistor and a fifth resistor;
one end of the fourth resistor is electrically connected with the grid electrode of the MOS tube;
the other end of the fourth resistor is electrically connected with an emitting electrode of the second triode;
one end of the fifth resistor is electrically connected with the grid electrode of the MOS tube;
the other end of the fifth resistor is electrically connected with the collector of the first triode.
6. The overcurrent protection circuit of claim 1, further comprising a sixth resistor;
one end of the sixth resistor is used as a control end of the overcurrent protection circuit and is electrically connected with a driving power supply;
the other end of the sixth resistor is electrically connected with the base electrode of the first triode.
7. The overcurrent protection circuit of claim 1, further comprising a seventh resistor;
one end of the seventh resistor is electrically connected with the base electrode of the second triode;
the other end of the seventh resistor is electrically connected with the source electrode of the MOS tube.
8. The overcurrent protection circuit according to claim 1, wherein a voltage of the drive power supply is 24V.
9. The overcurrent protection circuit of claim 1, wherein the first transistor is of type BC 847W;
the model of the second triode is BC 857W;
the MOS tube is FQB22P10 TM.
10. The overcurrent protection circuit of claim 4,
the model of the first diode is BAV70WT 1G;
the type of the second diode is the same as that of the first diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020831990.4U CN212435341U (en) | 2020-05-18 | 2020-05-18 | Overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020831990.4U CN212435341U (en) | 2020-05-18 | 2020-05-18 | Overcurrent protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN212435341U true CN212435341U (en) | 2021-01-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020831990.4U Active CN212435341U (en) | 2020-05-18 | 2020-05-18 | Overcurrent protection circuit |
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|---|---|
| CN (1) | CN212435341U (en) |
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- 2020-05-18 CN CN202020831990.4U patent/CN212435341U/en active Active
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