CN217240599U - Protection circuit and switching power supply comprising same - Google Patents
Protection circuit and switching power supply comprising same Download PDFInfo
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- CN217240599U CN217240599U CN202122914612.XU CN202122914612U CN217240599U CN 217240599 U CN217240599 U CN 217240599U CN 202122914612 U CN202122914612 U CN 202122914612U CN 217240599 U CN217240599 U CN 217240599U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The utility model discloses a protection circuit and a switch power supply comprising the same, wherein a primary side circuit of the switch power supply comprises an input filter capacitor, a main power switch tube and a primary side winding of a transformer, the positive electrode of the input filter capacitor is connected with the positive input and the negative electrode of the switch power supply are connected with the negative input of the switch power supply, the drain electrode of the main power switch tube is connected with the positive input of the switch power supply, and the source electrode of the main power switch tube is connected with the negative input of the switch power supply after passing through the primary side winding; one embodiment of the protection circuit comprises a cut-off circuit, which is connected in a line between one end of the input filter capacitor and the drain electrode of the main power switch tube and is used for cutting off a main power loop of the switch power supply when the primary side of the switch power supply is in short circuit, wherein the main power loop is a loop formed by the cut-off circuit, the main power switch tube and the primary side winding. The utility model discloses a switching power supply can realize the unusual protection of main power return circuit short circuit, and the customer need not external high-voltage fuse, does not influence switching power supply authentication, and the device that the cut-off circuit can adopt low withstand voltage value, and is with low costs.
Description
Technical Field
The utility model relates to a switching power supply, in particular to switching power supply's main power abnormal protection.
Background
The switch power supply is a power supply which utilizes modern power electronic technology to control the on-off time ratio of a switch tube and maintain stable output voltage, and at present, the switch power supply is widely applied to almost all electronic equipment with the characteristics of small size, light weight and high efficiency, and is an indispensable power supply mode for the rapid development of the current electronic information industry.
As shown in fig. 1, the switching power supply is a schematic diagram, in order not to affect the understanding of the technical solution of the present invention, the switching power supply only draws components closely related to the present invention, as shown in fig. 1, the primary side circuit of the switching power supply at least includes an input filter capacitor C1, a main power switch tube Q1 and a primary side winding N1 of a transformer, the positive electrode of the input filter capacitor C1 is connected to the input positive electrode of the switching power supply, the negative electrode of the input filter capacitor C1 is connected to the input negative electrode of the switching power supply, the drain electrode of the main power switch tube Q1 is connected to the input positive electrode of the switching power supply, and the source electrode of the input negative electrode of the switching power supply is connected to the input negative electrode of the switching power supply after passing through the primary side winding N1.
In recent years, with rapid development of power industries such as photovoltaic power generation and ultra-high voltage transmission, the input voltage of the switching power supply in such application scenarios is required to have high-voltage characteristics, and switching power supplies with input voltages ranging from 200V to 1500V and even with input maximum voltages of 4500V and above have been introduced on the market.
For the high-voltage switching power supply, when a customer uses the high-voltage switching power supply, a fuse is required to be connected between the input end of the switching power supply and the equipment end of the customer, when the customer excessively uses the switching power supply to cause abnormal short circuit of the main power, the fuse can be disconnected to play a role in protection, however, because the fuse is related to authentication, and some high-voltage input switching power supplies and external fuses need to select high-voltage type fuses, the voltage resistance value of the fuse should be at least the highest value of the input voltage of the switching power supply, if the maximum input voltage of the switching power supply is 1500V, the withstand voltage of the fuse needs to be 1500V, the fuse has large volume and higher cost, if customers do not want to adopt the external fuse with high price, when the main power of the switching power supply is abnormally short-circuited due to excessive use, a main power loop of the switching power supply can continuously generate heat, and potential safety hazards are generated on equipment of a client.
SUMMERY OF THE UTILITY MODEL
Therefore, the to-be-solved problem of the present invention is to provide a protection circuit and a switching power supply including the same, which can prevent the customer from using the switching power supply without the need of external expensive high-voltage fuse, and the circuit is simple and low in cost.
In order to solve the above problem, according to a first aspect of the present invention, there is provided a protection circuit comprising:
as a first implementation manner, the present invention provides a protection circuit for a switching power supply, wherein a primary circuit of the switching power supply at least includes an input filter capacitor, a main power switch tube and a primary winding of a transformer, a positive electrode of the input filter capacitor is connected to a positive input terminal and a negative input terminal of the switching power supply is connected to a negative input terminal of the switching power supply, a drain electrode of the main power switch tube is connected to a positive input terminal of the switching power supply, and a source electrode of the main power switch tube is connected to a negative input terminal of the switching power supply through the primary winding; the protection circuit comprises a cut-off circuit, the cut-off circuit is connected in a line between the anode of the input filter capacitor and the drain electrode of the main power switch tube and used for cutting off a main power loop of the switch power supply when the primary side of the switch power supply is in short circuit, and the main power loop is a loop formed by the cut-off circuit, the main power switch tube and the primary side winding.
As a second implementation manner, the present invention provides a protection circuit for a switching power supply, wherein a primary circuit of the switching power supply at least includes an input filter capacitor, a main power switch tube and a primary winding of a transformer, a positive electrode of the input filter capacitor is connected to a positive input terminal and a negative input terminal of the switching power supply is connected to a negative input terminal of the switching power supply, a drain electrode of the main power switch tube is connected to a positive input terminal of the switching power supply, and a source electrode of the main power switch tube is connected to a negative input terminal of the switching power supply through the primary winding; the protection circuit comprises a fuse, and the fuse is connected in a line between the anode of the input filter capacitor and the drain of the main power switch tube.
As a third embodiment, the present invention provides a protection circuit for a switching power supply, wherein a primary circuit of the switching power supply at least includes an input filter capacitor, a main power switch tube and a primary winding of a transformer, a positive electrode of the input filter capacitor is connected to a positive input terminal and a negative input terminal of the switching power supply is connected to a negative input terminal of the switching power supply, a drain electrode of the main power switch tube is connected to a positive input terminal of the switching power supply, and a source electrode of the main power switch tube is connected to a negative input terminal of the switching power supply through the primary winding; the protection circuit comprises a cut-off circuit, the cut-off circuit is connected in a line between the negative electrode of the input filter capacitor and the primary winding and used for cutting off a main power loop of the switching power supply when the primary side of the switching power supply is short-circuited, and the main power loop is a loop formed by the cut-off circuit, the main power switch tube and the primary winding.
As a fourth implementation manner, the present invention provides a protection circuit for a switching power supply, wherein a primary circuit of the switching power supply at least includes an input filter capacitor, a main power switch tube and a primary winding of a transformer, a positive electrode of the input filter capacitor is connected to a positive input terminal of the switching power supply, a negative input terminal of the input filter capacitor is connected to a negative input terminal of the switching power supply, a drain electrode of the main power switch tube is connected to a positive input terminal of the switching power supply, and a source electrode of the main power switch tube is connected to a negative input terminal of the switching power supply through the primary winding; the protection circuit comprises a fuse, and the fuse is connected in a line between the negative electrode of the input filter capacitor and the primary winding.
In the first or fourth embodiment, the voltage resistance of the fuse is 200V to 300V.
As a second aspect of the present invention, there is provided a switching power supply, comprising:
a switching power supply employs the protection circuit described in any one of the above.
Further, the highest input voltage of the switching power supply is more than 300V.
The utility model discloses a theory of operation will combine specific embodiment to explain, and it is not repeated here, the beneficial effects of the utility model reside in that:
(1) by connecting a cut-off circuit or a fuse into a circuit between one end of an input filter capacitor of the switching power supply and a drain electrode of the main power switch tube, the abnormal protection of the short circuit of the main power loop of the switching power supply can be realized, so that a client does not need to be externally connected with a high-voltage fuse and does not influence the authentication of the client;
(2) because the cutting circuit is connected behind the input filter capacitor, the starting-up impact current does not need to be considered, and therefore the cutting circuit or the fuse can be selected from components with low voltage withstanding values, and the cost is low.
Drawings
FIG. 1 is a schematic diagram of a switching power supply;
fig. 2 is a schematic diagram of an embodiment of a first protection circuit according to the present invention applied to the switching power supply shown in fig. 1;
fig. 3 is a schematic diagram of a second protection circuit according to the present invention applied to the switching power supply shown in fig. 1;
fig. 4 is a schematic diagram of a third protection circuit according to the present invention applied to the switching power supply shown in fig. 1;
fig. 5 is a schematic diagram of a fourth protection circuit according to an embodiment of the present invention, applied to the switching power supply shown in fig. 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The utility model discloses a protection circuit, the application is shown in FIG. 1 in switching power supply, switching power supply's primary circuit includes input filter capacitor C1 at least, the primary winding N1 of main power switch tube Q1 and transformer, input filter capacitor C1's anodal switch power's input is positive, negative pole switch power's input is negative, main power switch tube Q1's drain electrode switch power's input is positive, the source electrode is negative through primary winding N1 back switch power's input.
Fig. 2 is the schematic diagram of the embodiment of the first protection circuit applied in the switching power supply shown in fig. 1, see fig. 2, as the utility model discloses a first specific embodiment of protection circuit, including the cut-off circuit, the cut-off circuit is connected in the circuit between the positive pole of input filter capacitor C1 and main power switch tube Q1's drain electrode for the main power return circuit of disconnection switching power supply when the switching power supply primary side takes place the short circuit, and the main power return circuit is the return circuit that cut-off circuit, main power switch tube Q1 and primary winding N1 constitute.
After the switching power supply shown in fig. 1 comprises the cut-off circuit, when the primary side of the switching power supply is short-circuited, the main power loop of the switching power supply is cut off, so that potential safety hazards to customer equipment caused by continuous heating of the primary winding N1 of the transformer are avoided, the cut-off circuit is connected behind the input filter capacitor C1, starting-up impact current does not need to be considered, the cut-off circuit does not have special requirements on voltage resistance, cognition of the switching power supply is not influenced, and the cost of raw materials is favorably reduced.
Fig. 3 is a schematic diagram of an embodiment of the second protection circuit of the present invention applied to the switching power supply shown in fig. 1, referring to fig. 3, as a second specific embodiment of the protection circuit of the present invention, a fuse F1 is connected in a line between the positive electrode of the input filter capacitor C1 and the drain electrode of the main power switch Q1.
The working principle analysis of the protection circuit of the embodiment after being applied to the switching power supply shown in fig. 1 is as follows:
when the drain-source electrode of the main power switch tube Q1 is damaged due to excessive use of a switching power supply and the like, a main power loop formed by the fuse F1, the main power switch tube Q1 and the primary winding N1 of the transformer is equivalent to a short circuit, so that a large current flows through the primary winding N1, and at the moment, due to the existence of the fuse F1, the fuse F1 is fused by the large current, so that the main power loop is disconnected, and the potential safety hazard of the primary winding N1 of the transformer to equipment of a client due to continuous heating is avoided.
Because the fuse F1 is connected behind the input filter capacitor C1, the starting-up impact current does not need to be considered, and the fuse F1 is not connected with the input end of the switching power supply, so that a high-voltage fuse does not need to be selected, a fuse with a lower voltage withstanding value is generally adopted, for example, the voltage withstanding value of the fuse is 200V to 300V, so that the design requirement can be met, the fuse does not influence the product authentication, and the cost of raw materials of the fuse is favorably reduced.
Fig. 4 is the schematic diagram of the application of the embodiment of the third protection circuit in the switching power supply shown in fig. 1, see fig. 4, as the utility model discloses a protection circuit's third concrete embodiment, including the cut-off circuit, the cut-off circuit is connected in the circuit between the negative pole of input filter capacitor C1 and primary winding N1 for the main power return circuit of disconnection switching power supply when the switching power supply primary side takes place the short circuit, and the main power return circuit is the return circuit that cut-off circuit, main power switch pipe Q1 and primary winding N1 constitute.
The schematic diagram of fig. 4 is an equivalent of the schematic diagram of fig. 2, and the circuit of fig. 4 can also achieve the object of the invention of the present application.
Fig. 5 is a schematic diagram of an embodiment of the fourth protection circuit according to the present invention, which is applied to the switching power supply shown in fig. 1, and referring to fig. 5, as a fourth specific implementation manner of the protection circuit according to the present invention, a fuse F1 is connected in a line between a negative electrode of the input filter capacitor C1 and the primary winding N1.
The schematic diagram of fig. 5 is an equivalent of the schematic diagram of fig. 3, and the circuit of fig. 5 can also achieve the object of the invention of the present application.
It should be noted that, the protection circuit of the present invention can be implemented in a switching power supply with an input voltage within a conventional range, except for the switching power supply with a high input voltage described in the background art, but has the advantage of being general compared with the switching power supply with the same input voltage range in the market. The utility model discloses a protection circuit has solved the pain point of electric power industries such as photovoltaic power generation, super high voltage transmission, and it is very obvious to use the advantage in the higher switching power supply of input voltage, for example uses in the switching power supply that the highest input voltage is more than 300V the utility model discloses a behind the protection circuit, its advantage just can embody betterly.
The above is only the preferred embodiment of the present invention, and the embodiments of the present invention are not limited thereto, and according to the above-mentioned contents of the present invention, the common technical knowledge and the conventional means in the field are utilized, without departing from the above basic technical idea of the present invention, the present invention can also make other modifications, replacements or changes in various forms, and all fall within the protection scope of the present invention.
Claims (7)
1. A protection circuit is applied to a switching power supply, a primary side circuit of the switching power supply at least comprises an input filter capacitor, a main power switch tube and a primary side winding of a transformer, the positive pole of the input filter capacitor is connected with the input positive pole and the negative pole of the switching power supply and is connected with the input negative pole of the switching power supply, the drain electrode of the main power switch tube is connected with the input positive pole of the switching power supply, and the source electrode of the main power switch tube is connected with the input negative pole of the switching power supply after passing through the primary side winding; the method is characterized in that: the protection circuit comprises a cut-off circuit, the cut-off circuit is connected in a line between the anode of the input filter capacitor and the drain electrode of the main power switch tube and used for cutting off a main power loop of the switch power supply when the primary side of the switch power supply is in short circuit, and the main power loop is a loop formed by the cut-off circuit, the main power switch tube and the primary side winding.
2. A protection circuit is applied to a switching power supply, a primary side circuit of the switching power supply at least comprises an input filter capacitor, a main power switch tube and a primary side winding of a transformer, the positive pole of the input filter capacitor is connected with the input positive pole and the negative pole of the switching power supply and is connected with the input negative pole of the switching power supply, the drain electrode of the main power switch tube is connected with the input positive pole of the switching power supply, and the source electrode of the main power switch tube is connected with the input negative pole of the switching power supply after passing through the primary side winding; the method is characterized in that: the protection circuit comprises a fuse, and the fuse is connected in a line between the anode of the input filter capacitor and the drain of the main power switch tube.
3. A protection circuit is applied to a switching power supply, a primary side circuit of the switching power supply at least comprises an input filter capacitor, a main power switch tube and a primary side winding of a transformer, the positive pole of the input filter capacitor is connected with the input positive pole and the negative pole of the switching power supply and is connected with the input negative pole of the switching power supply, the drain electrode of the main power switch tube is connected with the input positive pole of the switching power supply, and the source electrode of the main power switch tube is connected with the input negative pole of the switching power supply after passing through the primary side winding; the method is characterized in that: the protection circuit comprises a cut-off circuit, the cut-off circuit is connected in a line between the negative electrode of the input filter capacitor and the primary winding and is used for cutting off a main power loop of the switching power supply when the primary side of the switching power supply is short-circuited, and the main power loop is a loop consisting of the cut-off circuit, the main power switch tube and the primary winding.
4. A protection circuit is applied to a switching power supply, a primary side circuit of the switching power supply at least comprises an input filter capacitor, a main power switch tube and a primary side winding of a transformer, the positive pole of the input filter capacitor is connected with the input positive pole and the negative pole of the switching power supply and is connected with the input negative pole of the switching power supply, the drain electrode of the main power switch tube is connected with the input positive pole of the switching power supply, and the source electrode of the main power switch tube is connected with the input negative pole of the switching power supply after passing through the primary side winding; the method is characterized in that: the protection circuit comprises a fuse, and the fuse is connected in a line between the negative electrode of the input filter capacitor and the primary winding.
5. The protection circuit of claim 4, wherein: the voltage withstanding value of the fuse is 200V to 300V.
6. A switching power supply, characterized by: use of a protection circuit according to any one of claims 1 to 5.
7. The switching power supply according to claim 6, wherein: the highest input voltage of the switching power supply is more than 300V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122914612.XU CN217240599U (en) | 2021-11-25 | 2021-11-25 | Protection circuit and switching power supply comprising same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122914612.XU CN217240599U (en) | 2021-11-25 | 2021-11-25 | Protection circuit and switching power supply comprising same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217240599U true CN217240599U (en) | 2022-08-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122914612.XU Active CN217240599U (en) | 2021-11-25 | 2021-11-25 | Protection circuit and switching power supply comprising same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217240599U (en) |
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2021
- 2021-11-25 CN CN202122914612.XU patent/CN217240599U/en active Active
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