CN214255696U - Overcurrent protection circuit and switching power supply - Google Patents
Overcurrent protection circuit and switching power supply Download PDFInfo
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- CN214255696U CN214255696U CN202022501055.4U CN202022501055U CN214255696U CN 214255696 U CN214255696 U CN 214255696U CN 202022501055 U CN202022501055 U CN 202022501055U CN 214255696 U CN214255696 U CN 214255696U
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Abstract
The utility model discloses an overcurrent protection circuit and switching power supply belongs to the circuit field. The overcurrent protection circuit comprises a current sampling module and an overcurrent protection module, wherein the current sampling module is used for collecting the current of the switching power supply; the overcurrent protection module comprises a Darlington tube and a control switch, wherein the base electrode of the Darlington tube is connected with the output end of the current sampling module, the collector electrode of the Darlington tube is connected with the voltage output end of the switching power supply, and the emitting electrode of the Darlington tube is grounded; the first end of the control switch is respectively connected with the collector of the Darlington tube, the voltage output end of the switching power supply and the control end of the switching power supply, and the second end of the control switch is connected with the emitter of the Darlington tube and the ground. The overcurrent protection circuit can quickly judge the overcurrent of the circuit and take corresponding protection measures, thereby ensuring the safety of the circuit in the working process.
Description
Technical Field
The utility model relates to a circuit field especially relates to an overcurrent protection circuit and switching power supply.
Background
In the current overcurrent protection technology, an MCU is usually adopted to acquire circuit current, and protective measures for the circuit are started after overcurrent exists in the circuit is determined, so that the reaction speed of starting the protective measures is low, and the safety of the circuit in the working process is influenced.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides an overcurrent protection circuit can overflow to the circuit and carry out quick judgement and take corresponding safeguard measure, has guaranteed the security of circuit in the course of the work.
The utility model discloses still provide a switching power supply who has above-mentioned overcurrent protection circuit.
According to utility model's first aspect embodiment overcurrent protection circuit, include:
the current sampling module is used for collecting the current of the switching power supply;
the overcurrent protection module is used for switching off the switching power supply according to the magnitude of the current collected by the current sampling module;
wherein, the overcurrent protection module includes:
a base electrode of the Darlington tube is connected with an output end of the current sampling module, a collector electrode of the Darlington tube is connected with a voltage output end of the switching power supply, and an emitting electrode of the Darlington tube is grounded;
and the first end of the control switch is respectively connected with the collector of the Darlington tube, the voltage output end of the switch power supply and the control end of the switch power supply, and the second end of the control switch is connected with the emitter and the ground of the Darlington tube.
According to the utility model discloses overcurrent protection circuit has following beneficial effect at least: the overcurrent protection circuit can sample the current of the switching power supply through the current sampling module, the overcurrent protection module further enables the Darlington tube to be switched on or switched off according to the current, and the action of the control switch is controlled through the switching on or switching off of the Darlington tube, so that the control switch can control the switching on or switching off of the switching power supply, the overcurrent of the circuit can be quickly judged, overcurrent protection is realized, and the safety of the circuit in the working process is ensured.
According to the utility model discloses a some embodiments, the current sampling module includes at least one sampling resistor, each the first end of sampling resistor with switching power supply's current output end the base of darlington pipe is connected, each the second end ground connection of sampling resistor.
According to some embodiments of the utility model, control switch is the thyristor, the positive pole of thyristor is connected respectively the collecting electrode of darlington pipe the voltage output end of switching power supply's control end, the negative pole of thyristor is connected respectively the projecting pole, the earthing terminal of darlington pipe, the gate pole of thyristor with the projecting pole of darlington pipe is connected.
According to some embodiments of the utility model, overcurrent protection circuit still includes:
and the input end of the current limiting module is connected with the overcurrent protection module, and the output end of the current limiting module is connected with the control end of the switching power supply.
According to some embodiments of the invention, the current limiting module comprises:
the first end of the first current-limiting resistor is connected with the voltage output end of the switching power supply and the collector of the Darlington tube, and the second end of the first current-limiting resistor is respectively connected with the control end of the switching power supply and the anode of the thyristor.
According to some embodiments of the invention, the current limiting module further comprises:
and the first end of the second current-limiting resistor is connected with the emitting electrode of the Darlington tube and the gate pole of the thyristor, and the second end of the second current-limiting resistor is connected with the cathode of the thyristor and the ground.
According to some embodiments of the utility model, overcurrent protection circuit still includes:
the input end of the comparison module is connected with the first end of the sampling resistor, the output end of the comparison module is connected with the base electrode of the Darlington tube, the comparison module is used for comparing the relation between the current and a preset threshold value and outputting a control signal according to the relation between the current and the threshold value, and the control signal is used for controlling the on-off of the Darlington tube.
According to the utility model discloses a some embodiments, the comparison module includes the comparator, the input of comparator with the first end of sampling resistance is connected, the output of comparator with the base of darlington pipe is connected.
According to some embodiments of the invention, the model of the darlington tube is 2N 6038.
According to the utility model discloses a switching power supply of second aspect embodiment, include according to the first aspect embodiment overcurrent protection circuit.
According to the utility model discloses switching power supply has following beneficial effect at least: the overcurrent protection circuit of the switch power supply adopting the embodiment can sample the current of the switch power supply through the current sampling module, the overcurrent protection module further enables the Darlington tube to be switched on or switched off according to the current, and the action of the control switch is controlled through the switching on or switching off of the Darlington tube, so that the control switch can control the switching on or switching off of the switch power supply, the rapid judgment and overcurrent protection of the circuit are realized, and the safety of the circuit in the working process is ensured.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The invention will be further described with reference to the following drawings and examples, in which:
fig. 1 is a block diagram of an overcurrent protection circuit according to an embodiment of the present invention;
fig. 2 is a block diagram of an overcurrent protection circuit according to another embodiment of the present invention;
fig. 3 is a circuit structure diagram of an overcurrent protection circuit according to another embodiment of the present invention.
Reference numerals: 110. a current sampling module; 120. an overcurrent protection module; 210. a current limiting module; 220. a comparison module; controlling the switch 310.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, a plurality of means is one or more, a plurality of means is two or more, and the terms greater than, less than, exceeding, etc. are understood as not including the number, and the terms greater than, less than, within, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.
In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In a first aspect, referring to fig. 1 and 3, an embodiment of the present invention provides an overcurrent protection circuit including: the current sampling module 110 and the overcurrent protection module 120 are used for collecting the current of the switching power supply; the overcurrent protection module 120 is configured to turn off the switching power supply according to the magnitude of the current collected by the current sampling module; wherein, the overcurrent protection module 120 includes: the device comprises a Darlington transistor Q1 and a control switch 310, wherein the base electrode of the Darlington transistor Q1 is connected with the output end of the current sampling module 110, the collector electrode of the Darlington transistor Q1 is connected with the voltage output end of a switching power supply, and the emitting electrode of the Darlington transistor Q1 is grounded; the first end of the control switch 310 is connected with the collector of the Darlington transistor Q1, the voltage output end of the switching power supply and the control end of the switching power supply respectively, and the end of the control switch 310 is connected with the emitter of the Darlington transistor Q1 and the ground.
Compared with a common triode, the Darlington tube has higher amplification factor and is more sensitive to signals in a detection circuit, and the Darlington tube Q1 serving as a main electronic component of the overcurrent protection module 120 can better detect the overcurrent of the circuit and take corresponding protection measures. In the working process of the circuit, the current sampling module 110 samples the current of the switching power supply, the current is input into the current sampling module 110 through the current output end of the switching power supply, the current sampling module 110 further converts the sampled current signal into a voltage signal and inputs the voltage signal into the overcurrent protection module 120, the overcurrent protection module 120 compares the received voltage signal with a preset threshold value, and the darlington tube Q1 is correspondingly turned off according to the comparison result, so that the on-off of the control switch 310 is controlled, and the purpose of overcurrent protection is achieved. For example, when the circuit is over-current, the current sampling module 110 samples a current, and accordingly, the received voltage signal is greater than a preset voltage threshold, the darlington tube Q1 is turned on, so that the control switch 310 is also turned on, and the switching power supply is turned off.
In some embodiments, in order to improve the rapid determination and protection of the overcurrent protection circuit for the overcurrent of the circuit, the darlington transistor Q1 in the overcurrent protection module 120 is a darlington transistor with a model number of 2N6038, and the amplification factor of the darlington transistor is large, which is beneficial to improving the sensitivity of the overcurrent protection circuit and the circuit breaking speed. It should be noted that in some other embodiments, other types of darlington tubes may be used, and are not limited thereto.
Referring to fig. 2 and 3, in some embodiments, the current sampling module 110 includes at least one sampling resistor R1, a first terminal of each sampling resistor R1 is connected to the current output terminal of the switching power supply and the base of the darlington transistor Q1, and a second terminal of each sampling resistor R1 is grounded. In some embodiments, the current sampling module 110 may be composed of one sampling resistor, or may be composed of a plurality of sampling resistors connected in series or a plurality of sampling resistors connected in parallel, which is not limited to this. For example, as shown in fig. 3, the current sampling module 110 includes a sampling resistor R1, a first terminal of the sampling resistor R1 is connected to the current output terminal of the switching power supply and the base of the darlington transistor Q1, and a second terminal of the sampling resistor R1 is grounded. The sampling resistor R1 selects a resistor with the precision of 0.01, when the circuit is overcurrent, the current sampling module 110 converts the sampled current into a voltage signal to be input into the overcurrent protection module for judgment, so that the on-off of the modulation circuit of the switching power supply is controlled, the purpose of overcurrent protection is achieved, the accurate detection of the overcurrent of the circuit by the overcurrent protection circuit can be ensured, and the speed and the precision of the overcurrent protection are improved.
Referring to fig. 3, in some embodiments, the control switch 310 is a thyristor, an anode of the thyristor 310 is connected to the collector of the darlington Q1, the voltage output terminal of the switching power supply, and the control terminal of the switching power supply, a cathode of the thyristor 310 is connected to the emitter of the darlington Q1 and the ground terminal, and a gate of the thyristor 310 is connected to the emitter of the darlington Q1. When the circuit is overcurrent, the current sampling module 110 samples current, a voltage signal converted from the sampled current signal is converted, if the received voltage signal is larger than a preset voltage threshold value, the darlington tube Q1 can be conducted, so that a control signal can be output to a gate pole of the thyristor 310, the thyristor 310 is conducted, at the moment, in the overcurrent protection circuit, the voltage at the input end of the modulation circuit of the switching power supply can be obviously reduced, normal power supply can not be carried out on the modulation circuit, namely, the power supply of the modulation circuit of the switching power supply is cut off, and the switching power supply stops working, so that the purposes of quickly judging the overcurrent of the circuit and overcurrent protection of the switching power supply are achieved, and the safety and reliability of the circuit in the working process are improved.
In some embodiments, in order to improve the applicability of the overcurrent protection circuit, the model of the thyristor can be 2N1595 or 2N 1596. In a high-power circuit, a thyristor with the model number of 2N1595 is selected as the control switch 310, and in a low-power circuit, a thyristor with the model number of 2N1596 is selected as the control switch 310, so that better overcurrent protection can be performed on circuits of various power sections, rapid judgment and turn-off protection can be performed on detected large current, and the applicability of an overcurrent protection circuit is ensured.
Referring to fig. 2 and 3, in some embodiments, the overcurrent protection circuit further includes a current limiting module 210, an input terminal of the current limiting module 210 is connected to the overcurrent protection module 120, and an output terminal of the current limiting module 210 is used for connecting a control terminal of the switching power supply. The current limiting module 210 is arranged in the overcurrent protection circuit, so that the current in the branches can be limited, when the overcurrent of the switching power supply is found, the current in each branch in the overcurrent protection circuit is effectively limited, the whole circuit is in a safe and stable state when the modulation circuit of the switching power supply is controlled to turn off the switching power supply, and the reliability of the circuit is improved.
In some embodiments, the current limiting module 210 includes a first current limiting resistor R3, a first end of the first current limiting resistor R2 is connected to the voltage output terminal of the switching power supply and the collector of the darlington transistor Q1, and a second end of the first current limiting resistor R2 is connected to the control terminal of the switching power supply and the anode of the thyristor 310, respectively. Therefore, the current of the branch where the thyristor 310 is located can be limited, circuit damage caused by overlarge current is avoided, the branch where the thyristor 310 is located is in a safe and stable state when the modulation circuit of the switching power supply is controlled to turn off the switching power supply, and the reliability of the circuit is improved.
In some embodiments, the current limiting module 210 further includes a second current limiting resistor R3, a first terminal of the second current limiting resistor R3 is connected to the emitter of the darlington Q1 and the gate of the thyristor 310, and a second terminal of the second current limiting resistor R3 is connected to the cathode of the thyristor 310 and ground. Can all restrict the electric current of darlington pipe Q1 place branch road like this, avoid the electric current too big circuit damage that causes, guarantee to be in the safety and stability state in darlington pipe Q1 branch road when controlling with turn-off switch power supply to the modulation circuit of assurance to switch power supply, improve the reliability of circuit.
It should be noted that, the resistance values of the first current limiting resistor and the second current limiting resistor may be set according to actual conditions, and the first current limiting resistor and the second current limiting resistor may be resistors having the same resistance value or resistors having different resistance values.
Referring to fig. 2, in some embodiments, the overcurrent protection circuit further includes a comparing module 220, an input terminal of the comparing module 220 is connected to the first terminal of the sampling resistor R1, an output terminal of the comparing module 220 is connected to a base of the darlington transistor, the comparing module 220 is configured to compare a relationship between a current and a preset threshold, and is configured to output a control signal according to the relationship between the current and the threshold, and the control signal is configured to control on/off of the darlington transistor Q1. After the current sampling module 110 samples the current of the switching power supply, the sampled current signal is converted into a voltage signal and is input into the comparison module 220, the voltage signal is compared with a preset voltage threshold value in the comparison module 220, if the voltage signal is greater than the preset voltage signal threshold value, the comparison module 220 controls the conduction of the darlington tube Q1 by the output control signal, so that the thyristor 310 is controlled to be conducted, the input voltage of the modulation circuit of the switching power supply is obviously reduced, the normal power supply of the modulation circuit cannot be realized, the modulation circuit stops working, and the turn-off protection of the switching power supply is realized.
Referring to fig. 3, in some embodiments, the comparing module 220 includes a comparator (not shown), an input of the comparator is connected to the first terminal of the sampling resistor, and an output of the comparator is connected to the base of the darlington Q1. Under the condition that the comparator judges that the current flowing through the sampling resistor R1 in the current sampling module 110 is larger than the preset threshold value, the comparator outputs a first control signal to enable the Darlington tube Q1 to be conducted, and the Darlington tube Q1 outputs a second control signal to the gate pole of the thyristor 310 to enable the thyristor 310 to be conducted.
In a second aspect, the embodiment of the present invention further provides a switching power supply, including the overcurrent protection circuit shown in the first aspect.
The overcurrent protection circuit of the switch power supply adopting the embodiment can sample the current of the switch power supply through the current sampling module, the overcurrent protection module further enables the Darlington tube to be switched on or switched off according to the current, and the action of the control switch is controlled through the switching on or switching off of the Darlington tube, so that the control switch can control the switching on or switching off of the switch power supply, the rapid judgment and overcurrent protection of the circuit are realized, and the safety of the circuit in the working process is ensured.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. Furthermore, the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.
Claims (10)
1. An overcurrent protection circuit, comprising:
the current sampling module is used for collecting the current of the switching power supply;
the overcurrent protection module is used for switching off the switching power supply according to the magnitude of the current collected by the current sampling module;
wherein, the overcurrent protection module includes:
a base electrode of the Darlington tube is connected with an output end of the current sampling module, a collector electrode of the Darlington tube is connected with a voltage output end of the switching power supply, and an emitting electrode of the Darlington tube is grounded;
and the first end of the control switch is respectively connected with the collector of the Darlington tube, the voltage output end of the switch power supply and the control end of the switch power supply, and the second end of the control switch is connected with the emitter and the ground of the Darlington tube.
2. The overcurrent protection circuit of claim 1, wherein the current sampling module comprises at least one sampling resistor, a first end of each sampling resistor is connected to the current output terminal of the switching power supply and the base of the darlington transistor, and a second end of each sampling resistor is grounded.
3. The overcurrent protection circuit of claim 2, wherein the control switch is a thyristor, an anode of the thyristor is connected to a collector of the darlington tube, a voltage output terminal of the switching power supply, and a control terminal of the switching power supply, a cathode of the thyristor is connected to an emitter and a ground terminal of the darlington tube, and a gate of the thyristor is connected to the emitter of the darlington tube.
4. The over-current protection circuit according to claim 3, further comprising:
and the input end of the current limiting module is connected with the overcurrent protection module, and the output end of the current limiting module is connected with the control end of the switching power supply.
5. The overcurrent protection circuit of claim 4, wherein the current limiting module comprises:
the first end of the first current-limiting resistor is connected with the voltage output end of the switching power supply and the collector of the Darlington tube, and the second end of the first current-limiting resistor is respectively connected with the control end of the switching power supply and the anode of the thyristor.
6. The overcurrent protection circuit of claim 4 or claim 5, wherein the current limiting module further comprises:
and the first end of the second current-limiting resistor is connected with the emitting electrode of the Darlington tube and the gate pole of the thyristor, and the second end of the second current-limiting resistor is connected with the cathode of the thyristor and the ground.
7. The over-current protection circuit according to claim 6, further comprising:
the input end of the comparison module is connected with the first end of the sampling resistor, the output end of the comparison module is connected with the base electrode of the Darlington tube, the comparison module is used for comparing the relation between the current and a preset threshold value and outputting a control signal according to the relation between the current and the threshold value, and the control signal is used for controlling the on-off of the Darlington tube.
8. The overcurrent protection circuit of claim 7, wherein the comparison module comprises a comparator, an input terminal of the comparator is connected to the first terminal of the sampling resistor, and an output terminal of the comparator is connected to the base of the Darlington transistor.
9. The overcurrent protection circuit of claim 8, wherein said darlington tube is 2N 6038.
10. Switching power supply, characterized in that it comprises an overcurrent protection circuit according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022501055.4U CN214255696U (en) | 2020-11-02 | 2020-11-02 | Overcurrent protection circuit and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202022501055.4U CN214255696U (en) | 2020-11-02 | 2020-11-02 | Overcurrent protection circuit and switching power supply |
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| CN214255696U true CN214255696U (en) | 2021-09-21 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109473957A (en) * | 2018-12-24 | 2019-03-15 | 南宁职业技术学院 | Current sink circuit |
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2020
- 2020-11-02 CN CN202022501055.4U patent/CN214255696U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109473957A (en) * | 2018-12-24 | 2019-03-15 | 南宁职业技术学院 | Current sink circuit |
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