CN217590599U - Protection circuit and switching power supply - Google Patents
Protection circuit and switching power supply Download PDFInfo
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- CN217590599U CN217590599U CN202123184353.6U CN202123184353U CN217590599U CN 217590599 U CN217590599 U CN 217590599U CN 202123184353 U CN202123184353 U CN 202123184353U CN 217590599 U CN217590599 U CN 217590599U
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Abstract
The utility model discloses a protection circuit is applied to switching power supply, and switching power supply is used for the load power supply, and protection circuit includes: the first one-way conduction circuit has one end connected to one output end of the switch power supply and the other end connected to one input end of the load, the polarity of one output end of the switch power supply is the same as that of one input end of the load, and the first one-way conduction circuit can only allow energy to flow from the switch power supply to the load; and one end of the absorption circuit is connected with one end of the first one-way conduction circuit, and the other end of the absorption circuit is connected with the other end of the first one-way conduction circuit and is used for absorbing the energy of the load flowing backwards to the switching power supply. The utility model discloses the circuit can absorb the backward flow energy that produces in the load working process, and the protection load is not damaged by the high pressure of backward flow energy production, has that circuit structure is simple and easy, with low costs, and the expansion of accessible circuit is extended simultaneously and is carried out the reutilization of backward flow energy, improves energy utilization's advantage.
Description
Technical Field
The present invention relates to a switching power supply, and more particularly, to a protection circuit for protecting a sensitive load connected to the switching power supply from being damaged.
Background
The switching power supply makes electronic switching devices (such as transistors, field effect transistors, thyristor and the like) continuously switched on and off through a control circuit, and makes the electronic switching devices perform pulse modulation on input voltage, so that the functions of DC/AC and DC/DC voltage conversion, adjustable output voltage, automatic voltage stabilization and the like are realized. At present, the switching power supply is widely applied to almost all electronic devices with the characteristics of small size, light weight and high efficiency, and is an indispensable power supply mode for the rapid development of the electronic information industry at present.
Because a switching device in the switching power supply has bidirectional conductive performance, as the application scenes of the switching power supply are continuously increased, aiming at load-end inductive loads (motors, motors and the like), at the moment of starting and stopping the switching power supply, the load end can generate larger backward flow energy, and after the backward flow energy is reversely input into the switching power supply, the internal components of the switching power supply can be damaged. When the reverse flow is prevented by simply using components such as a diode or an MOS (metal oxide semiconductor) and the like, the reverse flow energy cannot be absorbed, so that the reverse flow energy at the load end cannot be released, transient high voltage is generated, the load is damaged, and the device is not suitable for various occasions.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a protection circuit can not only prevent that the energy of load end from flowing backward to switching power supply, prevents to flow backward energy damage switching power supply, can also absorb the energy of flowing backward that produces among the switching power supply load operation process, prevents to flow backward the unable release of energy, produces the high pressure damage load of transient state.
As a first aspect of the present invention, the protection circuit provided has the following technical solutions:
as a specific implementation manner of the protection circuit, the protection circuit is applied to a switching power supply, where the switching power supply is used to supply power to a load, and the protection circuit includes:
a first unidirectional conducting circuit, one end of which is used for connecting with an output end of the switching power supply and the other end of which is used for connecting with an input end of the load, wherein the polarity of the output end of the switching power supply is the same as that of the input end of the load, and the first unidirectional conducting circuit can only allow energy to flow from the switching power supply to the load;
and one end of the absorption circuit is connected with one end of the first one-way conduction circuit, and the other end of the absorption circuit is connected with the other end of the first one-way conduction circuit and is used for absorbing the energy of the load flowing backwards to the switching power supply.
As a specific implementation manner of the first unidirectional conducting circuit, the first unidirectional conducting circuit is a diode D2, an anode of the diode D2 is one end of the first unidirectional conducting circuit, and a cathode of the diode D2 is the other end of the first unidirectional conducting circuit.
The absorption circuit comprises a resistor R1, a capacitor C1 and a second unidirectional conducting circuit; one end of the resistor R1 and one end of the capacitor C1 are simultaneously connected with one end of the first one-way conduction circuit, the other end of the first one-way conduction circuit is connected with one end of the second one-way conduction circuit, the other end of the second one-way conduction circuit is simultaneously connected with the other end of the resistor R1 and the other end of the capacitor C1, and the second one-way conduction circuit can only allow energy to flow from the other end of the first one-way conduction circuit to the capacitor C1.
As a specific embodiment of the second unidirectional conducting circuit, the second unidirectional conducting circuit is a diode D1, an anode of the diode D1 is one end of the second unidirectional conducting circuit, and a cathode of the diode D1 is the other end of the second unidirectional conducting circuit.
As another specific embodiment of the second unidirectional conducting circuit, the second unidirectional conducting circuit is a MOS transistor Q1, a drain of the MOS transistor Q1 is one end of the second unidirectional conducting circuit, and a source of the MOS transistor Q1 is the other end of the second unidirectional conducting circuit.
As another specific implementation of the protection circuit, the protection circuit is applied to a switching power supply, where the switching power supply is used to supply power to a load, and the protection circuit includes: diode D1, diode D2, resistance R1 and electric capacity C1, resistance R1's one end resistance C1's one end with diode D2's positive pole link together for connect switching power supply's an output, diode D2's negative pole with diode D1's negative pole link together for connect an input of load, switching power supply's an output with the polarity of an input of load the same, diode D1's negative pole connect resistance R1's the other end with electric capacity C1's the other end.
As another specific implementation of the protection circuit, the protection circuit is applied to a switching power supply, where the switching power supply is configured to supply power to a load, and the protection circuit includes: MOS pipe Q1, diode D2, resistance R1 and electric capacity C1, resistance R1's one end resistance C1's one end with diode D2's positive pole link together for connect switching power supply's an output, diode D2's negative pole with MOS pipe Q1's drain electrode link together for connect a load's an input, switching power supply's an output with the polarity of a load the same, MOS pipe Q1's source electrode connect resistance R1's the other end with electric capacity C1's the other end.
As a second aspect of the present invention, there is provided a switching power supply comprising:
a switching power supply comprising a protection circuit as claimed in any one of the preceding claims.
The utility model discloses a theory of operation will combine specific embodiment to carry out detailed analysis, and it is not repeated here, compares with prior art, the utility model discloses following beneficial effect has:
(1) the load to switching power supply is the situation of perceptual loads such as motors, the utility model discloses an among the protection circuit because including first one-way conduction circuit and absorption circuit, wherein first one-way conduction circuit can prevent that the energy from flowing backward to switching power supply by this type of load, avoid flowing backward energy damage switching power supply, absorption circuit wherein can absorb the energy that flows backward that this type of load produced, prevent the unable release of energy, produce the high pressure, arouse the load to damage, thereby the problem of the energy that flows backward that switching power supply's load produced in the operation process damage load and switching power supply itself has effectively been solved.
(2) The utility model discloses a concrete realization circuit of protection circuit is simple, only uses diode, resistance, electric capacity etc. to realize, consequently with low costs to go back the secondary utilization of flowing backward energy is realized to the components and parts selection of accessible concrete realization circuit, the utilization ratio of the high energy.
(3) The utility model discloses a specific embodiment that absorption circuit among the protection circuit relates to only can realize absorbing bigger energy of flowing backward through increase electric capacity C1's appearance value, and through the mode of putting electric capacity C1 one end and connecting at the positive output of switching power supply, greatly reduced the withstand voltage requirement to electric capacity C1.
(4) The utility model discloses owing to set up absorption circuit among the protection circuit, can effectively reduce the stress of first one-way conduction circuit for when selecting diode or MOS pipe as first one-way conduction circuit, can reduce lectotype pressure and cost.
Drawings
Fig. 1 is a diagram of a protection circuit structure according to an embodiment of the present invention;
fig. 2 is a diagram of a protection circuit according to another embodiment of the present invention;
fig. 3 is a diagram of a protection circuit according to still another embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present invention clearer, the following description is given to the embodiments of the present invention in combination with the accompanying drawings. It should be understood that the embodiments described are part of the present invention, and those skilled in the art can make various other changes, substitutions and alterations without any creative effort, and still fall within the protection scope of the present invention.
Fig. 1 is the protection circuit structure of an embodiment of the present invention, as the utility model discloses a protection circuit's a specific embodiment is applied to switching power supply, and switching power supply is used for supplying power for the load, and protection circuit includes:
the first one-way conduction circuit has one end connected to one output end of the switch power supply and the other end connected to one input end of the load, the polarity of one output end of the switch power supply is the same as that of one input end of the load, and the first one-way conduction circuit can only allow energy to flow from the switch power supply to the load;
and one end of the absorption circuit is connected with one end of the first one-way conduction circuit, and the other end of the absorption circuit is connected with the other end of the first one-way conduction circuit and is used for absorbing the energy of the load flowing backwards to the switching power supply.
The protection circuit of this embodiment can be regarded as a two-terminal assembly as a whole, and one end of the first unidirectional conduction circuit is one end of the two-terminal assembly, and the other end of the first unidirectional conduction circuit is the other end of the two-terminal assembly, and the application scenario includes the following two kinds of situations:
(1) The two-terminal assembly is designed in the switching power supply by a switching power supply manufacturer and is arranged in a circuit where a positive output end or a negative output end of the switching power supply is arranged;
(2) The two-terminal assembly is designed in a circuit board of a switching power supply user, when one end of the two-terminal assembly is selected to be connected with a positive output end of the switching power supply, the other end of the two-terminal assembly is connected with a positive input end of a load, and when one end of the two-terminal assembly is selected to be connected with a negative output end of the switching power supply, the other end of the two-terminal assembly is connected with a negative input end of the load.
After the protection circuit of the embodiment is added between the switching power supply and the load through the two modes, for inductive loads such as motors and the like, the energy can be prevented from flowing backwards from the loads to the switching power supply through the first one-way conduction circuit, the switching power supply is prevented from being damaged by the energy flowing backwards, the energy flowing backwards generated by the loads can be absorbed through the absorption circuit, the energy can be prevented from being released, transient high voltage is generated, the load is damaged, and the problem that the load and the switching power supply are damaged by the energy flowing backwards is effectively solved.
Fig. 2 is a protection circuit structure diagram of another embodiment of the present invention, applied to a switching power supply, the switching power supply is used for supplying power to a load, and the protection circuit includes: the circuit comprises a diode D1, a diode D2, a resistor R1 and a capacitor C1, wherein one end of the resistor R1 and one end of the capacitor C1 are connected with the anode of the diode D2 and are used for being connected with one output end of a switching power supply, the cathode of the diode D2 is connected with the cathode of the diode D1 and is used for being connected with one input end of a load, the polarity of one output end of the switching power supply is the same as that of one input end of the load, and the cathode of the diode D1 is connected with the other end of the resistor R1 and the other end of the capacitor C1; fig. 3 is a protection circuit structure diagram of another embodiment of the present invention, applied to a switching power supply, the switching power supply is used for supplying power to a load, and the protection circuit includes: MOS pipe Q1, diode D2, resistance R1 and electric capacity C1, resistance R1's one end, electric capacity C1's one end and diode D2's positive pole link together for connect switching power supply's an output, diode D2's negative pole and MOS pipe Q1's drain electrode link together, an input for connecting the load, switching power supply's an output is the same with the polarity of an input of load, MOS pipe Q1's source electrode connecting resistance R1's the other end and electric capacity C1's the other end.
Referring to fig. 2 and 3, a specific embodiment of the first unidirectional conducting circuit is a diode D2, an anode of the diode D2 is one end of the first unidirectional conducting circuit, and a cathode of the diode D2 is the other end of the first unidirectional conducting circuit.
The diode D2 can only allow energy to flow from the switching power supply to the load because the diode has the functions of forward conduction and reverse cutoff, and thus can be used as a specific implementation of the one-way conduction circuit in the embodiment.
Referring to fig. 2 and 3, as a specific embodiment of the absorption circuit, the absorption circuit includes a resistor R1, a capacitor C1, and a second unidirectional conducting circuit; one end of the resistor R1 and one end of the capacitor C1 are connected with one end of the first one-way conduction circuit at the same time, the other end of the first one-way conduction circuit is connected with one end of the second one-way conduction circuit, the other end of the second one-way conduction circuit is connected with the other end of the resistor R1 and the other end of the capacitor C1 at the same time, and the second one-way conduction circuit can only allow energy to flow to the capacitor C1 from the other end of the first one-way conduction circuit.
Because the second unidirectional circuit can only allow energy to flow to the capacitor C1 from the other end of the first unidirectional circuit, when backward flow energy is generated in the working process of the load, the backward flow energy is absorbed by the capacitor C1 through the second unidirectional circuit and the loop of the capacitor C1, the capacitance value of the capacitor C1 is related to the size of the backward flow energy required to be absorbed, when the backward flow energy to be absorbed is larger, the capacitance value of the capacitor C1 is also larger, and the voltage withstanding requirement on the capacitor C1 can be greatly reduced by placing one end of the capacitor C1 at the power output end Vo + in the graph 2 and the graph 3. The resistor R1 is used for discharging energy on the capacitor C1, so that the backward flow energy is prevented from being accumulated on the capacitor C1 and exceeding the upper withstand voltage limit bearable by the capacitor C1, and the absorption effect is influenced.
Referring to fig. 2, as a specific embodiment of the second unidirectional conducting circuit, the second unidirectional conducting circuit is a diode D1, an anode of the diode D1 is one end of the second unidirectional conducting circuit, and a cathode of the diode D1 is the other end of the second unidirectional conducting circuit.
The diode D1 can only allow energy to flow from the other end of the first unidirectional turn-on circuit to the capacitor C1 because the diode has the functions of forward turn-on and reverse turn-off, and thus can be used as a specific implementation of the second unidirectional turn-on circuit in this embodiment.
Referring to fig. 3, another specific embodiment of the second unidirectional conducting circuit is a MOS transistor Q1, a drain of the MOS transistor Q1 is one end of the second unidirectional conducting circuit, and a source of the MOS transistor Q1 is the other end of the second unidirectional conducting circuit.
A body diode is arranged in the MOS transistor Q1, which is equivalent to the diode D1 in fig. 2, the backward flow energy generated by the load end is absorbed by the capacitor C1 through the body diode of the MOS transistor Q1, and the gate of the MOS transistor Q1 is also externally connected with a control signal, when it is detected that a current flows through the MOS transistor Q1, the drain and the source of the MOS transistor Q1 are turned on, the backward flow energy generated by the load end can also be absorbed by the capacitor C1 after passing through the drain and the source of the MOS transistor Q1, because the MOS transistor Q1 has a bidirectional conduction function, after the backward flow energy is absorbed, the external control signal of the gate of the MOS transistor Q1 can be controlled again to be turned on through the external control signal, the energy absorbed by the capacitor C1 flows into the load end through the source and the drain of the MOS transistor Q1, and is recycled, when it is detected that the energy on the capacitor C1 is consumed to a certain value, the external control signal of the gate of the MOS transistor Q1 becomes low, and the drain and the source of the MOS transistor Q1 is turned off. In fig. 3, the resistor R1 functions to consume the energy remaining on the capacitor C1 before the end of each backward energy period, and to reset the initial value of the capacitor C1 to start from 0 in the next backward energy period; because a large amount of energy is fed back to the load end from the MOS transistor Q1, the energy to be consumed on the resistor R1 is small, the value of the resistor R1 can be large, and the rated power can be small.
The MOS tube adopted by the second unidirectional conduction circuit has the following advantages compared with a diode:
1. the backward flow energy can be recycled, so that the energy utilization rate is improved;
2. when the MOS tube is adopted, the resistor R1 does not need to consume all the backward flow energy in each backward flow energy period, and only needs to consume the residual energy on the capacitor C1, so that the resistor R1 can be a resistor with a larger resistance value and a smaller rated power, and the volume of a protection circuit is reduced.
It should be noted that the protection circuits of fig. 1 to 3 are all connected between the positive output terminal of the switching power supply and the positive input terminal of the load, which should not constitute a limitation of the present invention, and the protection circuit of the present invention may also be connected between the negative output terminal of the switching power supply and the negative input terminal of the load, which is an equivalent conversion scheme easily imaginable to those skilled in the art.
The technical solution of the present invention is described above only by way of illustration rather than limitation, and although the present invention is described in detail according to the embodiments, those skilled in the art can modify or replace the specific embodiments of the present invention, and any modification or replacement that does not depart from the spirit and scope of the present invention is within the protection scope of the claims of the present invention.
Claims (8)
1. A protection circuit applied to a switching power supply, the switching power supply being used for supplying power to a load, the protection circuit comprising:
a first unidirectional conducting circuit, one end of which is used for connecting with an output end of the switching power supply and the other end of which is used for connecting with an input end of the load, wherein the polarity of the output end of the switching power supply is the same as that of the input end of the load, and the first unidirectional conducting circuit can only allow energy to flow from the switching power supply to the load;
and one end of the absorption circuit is connected with one end of the first one-way conduction circuit, the other end of the absorption circuit is connected with the other end of the first one-way conduction circuit, and the absorption circuit is used for absorbing the energy of the load flowing backwards to the switching power supply.
2. The protection circuit of claim 1, wherein: the first unidirectional conduction circuit is a diode D2, the anode of the diode D2 is one end of the first unidirectional conduction circuit, and the cathode of the diode D2 is the other end of the first unidirectional conduction circuit.
3. The protection circuit of claim 1, wherein: the absorption circuit comprises a resistor R1, a capacitor C1 and a second one-way conduction circuit; one end of the resistor R1 and one end of the capacitor C1 are simultaneously connected with one end of the first one-way conduction circuit, the other end of the first one-way conduction circuit is connected with one end of the second one-way conduction circuit, the other end of the second one-way conduction circuit is simultaneously connected with the other end of the resistor R1 and the other end of the capacitor C1, and the second one-way conduction circuit can only allow energy to flow from the other end of the first one-way conduction circuit to the capacitor C1.
4. The protection circuit of claim 3, wherein: the second unidirectional conduction circuit is a diode D1, the anode of the diode D1 is one end of the second unidirectional conduction circuit, and the cathode of the diode D1 is the other end of the second unidirectional conduction circuit.
5. The protection circuit of claim 3, wherein: the second unidirectional conduction circuit is an MOS tube Q1, the drain electrode of the MOS tube Q1 is one end of the second unidirectional conduction circuit, and the source electrode of the MOS tube Q1 is the other end of the second unidirectional conduction circuit.
6. A protection circuit applied to a switching power supply, the switching power supply being used for supplying power to a load, the protection circuit comprising: diode D1, diode D2, resistance R1 and electric capacity C1, resistance R1's one end resistance C1's one end with diode D2's positive pole link together for connect switching power supply's an output, diode D2's negative pole with diode D1's negative pole link together for connect an input of load, switching power supply's an output with the polarity of an input of load the same, diode D1's negative pole connect resistance R1's the other end with electric capacity C1's the other end.
7. A protection circuit applied to a switching power supply, the switching power supply being used for supplying power to a load, the protection circuit comprising: MOS pipe Q1, diode D2, resistance R1 and electric capacity C1, resistance R1's one end resistance C1's one end with diode D2's positive pole link together for connect switching power supply's an output, diode D2's negative pole with MOS pipe Q1's drain electrode link together for connect a load's an input, switching power supply's an output with the polarity of a load the same, MOS pipe Q1's source electrode connect resistance R1's the other end with electric capacity C1's the other end.
8. A switching power supply, characterized by: comprising a protection circuit as claimed in any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123184353.6U CN217590599U (en) | 2021-12-17 | 2021-12-17 | Protection circuit and switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123184353.6U CN217590599U (en) | 2021-12-17 | 2021-12-17 | Protection circuit and switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217590599U true CN217590599U (en) | 2022-10-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123184353.6U Active CN217590599U (en) | 2021-12-17 | 2021-12-17 | Protection circuit and switching power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217590599U (en) |
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2021
- 2021-12-17 CN CN202123184353.6U patent/CN217590599U/en active Active
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