CN215681791U - Surge protection circuit and electrical equipment - Google Patents
Surge protection circuit and electrical equipment Download PDFInfo
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- CN215681791U CN215681791U CN202121879802.6U CN202121879802U CN215681791U CN 215681791 U CN215681791 U CN 215681791U CN 202121879802 U CN202121879802 U CN 202121879802U CN 215681791 U CN215681791 U CN 215681791U
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- 230000001419 dependent effect Effects 0.000 claims description 21
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- 101000645421 Homo sapiens Transmembrane protein 165 Proteins 0.000 description 20
- 102100025755 Transmembrane protein 165 Human genes 0.000 description 20
- 230000001965 increasing effect Effects 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 238000013021 overheating Methods 0.000 description 1
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Abstract
The utility model discloses a surge protection circuit and electrical equipment, wherein the surge protection circuit comprises a primary protection circuit and a secondary protection circuit which are sequentially connected between a power supply and a circuit to be protected, the primary protection circuit and the secondary protection circuit are arranged in parallel, the primary protection circuit comprises a protective tube and a first piezoresistor which are sequentially arranged, the protective tube is connected in series at the input end of the power supply, the first piezoresistor is connected in parallel at the input end of the power supply, and the secondary protection circuit is connected between the first piezoresistor and the circuit to be protected. According to the surge protection circuit and the electrical equipment, the super-strong surge protection effect is achieved by adopting the combination of the multi-stage protection circuit, and the residual voltage and the residual energy after the surge are effectively reduced, so that the circuit to be protected is effectively and reliably protected from being damaged by the surge.
Description
Technical Field
The utility model belongs to the technical field of surge protection, and particularly relates to a surge protection circuit and electrical equipment.
Background
In the circuit, it is often interfered by external transient overvoltage, and these interference sources mainly include: operating overvoltage due to on-off inductive load or on-off high-power load, line fault and the like; lightning surge caused by natural phenomena such as lightning is transient interference, and the surge voltage can seriously damage the safe operation of an electronic system. Eliminating surge noise interference and preventing surge damage are always the core problems related to safe and reliable operation of electronic equipment.
In the prior art, a voltage dependent resistor is usually selected as a protection device in a surge protection circuit. Because the voltage resistance of the piezoresistor is low, in order to meet the requirement of lightning surge protection, the piezoresistor is generally required to be taken down during safety test, however, the voltage resistance requirement of the current safety certification is high, a regular certification authority requires a complete unit to be certified, and the voltage resistance is not allowed to be taken down so as to meet the voltage resistance requirement. Therefore, in the surge protection circuit in the prior art, the requirements for protecting lightning surge and safety voltage resistance are difficult to meet at the same time.
In the conventional surge protection circuit, the residual voltage and residual energy on the piezoresistor are large after the surge, the anti-surge capacity is not strong enough, and the circuit to be protected is easily damaged.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problems mentioned in the background art, the utility model provides a surge protection circuit and electrical equipment, which are used for solving the technical problem that the residual voltage and residual energy of a piezoresistor are large and still cause the damage of a circuit to be protected after the surge of the conventional surge protection circuit.
In order to achieve the above purpose, the specific technical scheme of the surge protection circuit and the electrical equipment of the utility model is as follows:
the surge protection circuit provided by the embodiment of the utility model comprises a primary protection circuit and a secondary protection circuit which are sequentially connected between a power supply and a circuit to be protected, wherein the primary protection circuit and the secondary protection circuit are arranged in parallel, the primary protection circuit comprises a protective tube and a first piezoresistor which are sequentially arranged, the protective tube is connected in series at the input end of the power supply, the first piezoresistor is connected in parallel at the input end of the power supply, and the secondary protection circuit is connected between the first piezoresistor and the circuit to be protected.
Further, the secondary protection circuit comprises a discharge tube, and the discharge tube is connected with the circuit to be protected in parallel.
Further, the surge protection circuit further comprises a third protection circuit;
the third protection circuit comprises a first thermistor and a second thermistor which are sequentially arranged, the first thermistor is connected with the discharge tube and a connection point of the circuit to be protected, and the second thermistor is connected with the circuit to be protected in parallel.
Further, the third protection circuit further comprises a second thermistor, and the second thermistor is connected between the second voltage dependent resistor and the discharge tube.
Further, the first thermistor and the second thermistor are NTC resistors.
Further, the surge protection circuit further comprises a fourth protection circuit;
the fourth protection circuit comprises a TVS tube, the TVS tube is connected between the second voltage dependent resistor and the circuit to be protected, and the TVS tube is connected with the circuit to be protected in parallel.
Further, a primary circuit is connected between the first piezoresistor and the discharge tube.
Further, the primary circuit includes an EMI circuit or a rectifier bridge circuit.
The embodiment of the utility model also provides electric equipment which comprises the surge protection circuit.
According to the surge protection circuit and the electrical equipment, the super-strong surge protection effect is achieved by adopting the combination of the multi-stage protection circuit, and the residual voltage and the residual energy after the surge are effectively reduced, so that the circuit to be protected is effectively and reliably protected from being damaged by the surge.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
Fig. 1 is a schematic circuit diagram of a surge protection circuit according to an embodiment of the present invention;
fig. 2 is a graph of voltage versus time for a surge protection circuit provided by an embodiment of the utility model;
fig. 3 is a graph showing the relationship between the current of the surge protection circuit and the time variation.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Fig. 1 schematically shows a circuit schematic of a surge protection circuit. As shown in fig. 1, a surge protection circuit includes a primary protection circuit and a secondary protection circuit, the primary protection circuit and the secondary protection circuit are arranged in parallel, the primary protection circuit includes a FUSE1 and a first voltage dependent resistor R1 which are arranged in sequence, the FUSE1 is connected in series at a power input end, the first voltage dependent resistor R1 is connected in parallel at the power input end, and the secondary protection circuit is connected between the first voltage dependent resistor R1 and a circuit to be protected.
In the existing surge protection circuit, only including FUSE1 and first piezo-resistor R1, when entering power input end 1 by the unusual surge, first piezo-resistor R1 will be with ns rank speed (about 25 ns), make the resistance of first piezo-resistor R1 reduce rapidly, at this moment, after the electric current passes FUSE1 by power input end 1, most electric current is passing first piezo-resistor R1, flow back to input end 2 of power, thus do not pass the components and parts of the circuit to be protected, thus avoid waiting that the components and parts of the circuit to be protected cause the damage because of heavy current or large voltage.
The FUSE1 is used to open the FUSE1 when the current is abnormally large, so as to protect the circuit to be protected. Because the first voltage dependent resistor R1 belongs to a voltage limiting type protection device, when a large current flows through the first voltage dependent resistor R1, a residual voltage is generated on the first voltage dependent resistor R1, and the larger the current flowing through the first voltage dependent resistor R1 is, the higher the residual voltage is, and the residual voltage generally deviates from the nominal voltage of the first voltage dependent resistor more.
In this embodiment, the secondary protection circuit includes a discharge tube GDT1, one end of the discharge tube GDT1 is connected to the connection point of the first voltage dependent resistor R1 and the FUSE1, the other end is connected to the zero line of the power supply, and the discharge tube GDT1 is connected in parallel with the circuit to be protected.
Parallelly connected access a discharge tube GDT1 on the live wire of power, because discharge tube GDT1 belongs to switch mode protection device, if the voltage at discharge tube GDT1 both ends is greater than when the protection specification value of predetermineeing, the short circuit phenomenon can appear in discharge tube GDT1 inside to absorb the surge of input, turn into light energy and heat energy with unusual electric energy, so its residual voltage is very low, can reduce the residual voltage on the first piezo-resistor R1 to very low level.
The discharge tube GDT1 can only be put behind the first varistor R1, and the FUSE1 and the primary protection circuit formed by the first varistor R1 are indispensable. Because the residual voltage and residual energy of the abnormal surge after passing through the primary protection circuit are low, the residual voltage and residual energy of the first piezoresistor R1 are protected by the discharge tube GDT1, and the reliability and protection effect of the circuit can be improved. If the primary protection circuit is not provided and the power input is directly connected to the discharge tube GDT1, the voltage and energy required to be absorbed by the discharge tube GDT1 are large, and the discharge tube GDT1 may not be effectively protected, reliably protected for a long time, or even damaged due to overheating.
In this embodiment, the surge protection circuit further includes a third protection circuit; the third protection circuit comprises a first thermistor R2 and a second thermistor R4 which are sequentially arranged, the first thermistor R2 is connected with a discharge tube GDT1 and a connection point of a circuit to be protected, and the second thermistor R4 is arranged in parallel with the circuit to be protected.
In another embodiment, the third protection circuit further includes a second thermistor R3, and the second thermistor R3 is connected between the second varistor R4 and the discharge tube GDT 1.
Although the discharge tube GDT1 has a certain anti-surge effect, the gas discharge tube GDT1 has the disadvantages that the discharge time delay (i.e., response time) is large, the operation sensitivity is not ideal, the response time is generally 200 ns-300 ns, and the fastest time is about 100ns, and before the gas discharge tube is not turned on, a sharp pulse with a large amplitude leaks out, so that the protection effect cannot be achieved.
The circuit of the second voltage dependent resistor R4 is needed for further protection. When the sharp pulse leaked from the discharge tube GDT1 reaches the second piezoresistor R4, the resistance of the second piezoresistor R4 is rapidly reduced, and at this time, after the current passes through the first thermistor R2, most of the current passes through the loop of the second piezoresistor R4 and flows back to the second thermistor R3, and does not pass through the components of the circuit to be protected, so as to protect the circuit to be protected.
Specifically, the first thermistor R2 and the second thermistor R3 are NTC resistors, and the NTC resistors are used for increasing loop impedance and reducing the current magnitude of a surge spike pulse leaking from the discharge tube GDT1 to a circuit where the second varistor R4 is located, so that residual voltage during protection of the second varistor R4 is reduced, and the smaller the current flowing through the varistor, the lower the residual voltage. The NTC resistor is arranged at the series position of the second voltage dependent resistor R4 and is not arranged in the circuit where the first voltage dependent resistor R1 and the discharge tube GDT1 are arranged, and the better protection effect can be achieved by current limiting through the NTC resistor after the surge of the power input end is weakened through the circuit where the first voltage dependent resistor R1 and the discharge tube GDT1 are arranged.
In this embodiment, the surge protection circuit further includes a fourth protection circuit; the fourth protection circuit comprises a TVS tube which is connected between the second voltage dependent resistor R4 and the circuit to be protected. One end of the TVS tube is connected to the connection point of the first thermistor R2 and the second piezoresistor R4, the other end of the TVS tube is connected to the connection point of the second thermistor R3 and the second piezoresistor R4, and the TVS tube is connected in parallel with a circuit to be protected.
The residual voltage and energy of the surge at the power input end after being protected by the first voltage dependent resistor R1, the discharge tube GDT1 and the second voltage dependent resistor R4 are low. At the moment, the TVS tube is used for further protection, so that the super surge protection capability can be achieved.
The TVS tube belongs to a voltage limiting type protection device like a voltage dependent resistor, but the response speed of the TVS tube is very high (always in ps level), and the TVS tube is used as the last stage of protection, so that the surge which is not protected in the front and the residual voltage and the residual energy which are protected in the front can be effectively protected. Meanwhile, as the current carrying capacity of the TVS tube is weaker than that of the piezoresistor and the discharge tube, the surge is weakened by the piezoresistor and the discharge tube, and then the TVS tube is used for the last stage of protection, so that the TVS tube is more reliable and stable.
Furthermore, a primary circuit is connected between the first piezoresistor and the discharge tube, one end of the primary circuit is connected to a connection point of the first piezoresistor and the discharge tube, and the other end of the primary circuit is connected to the other connection point of the first piezoresistor and the discharge tube. Specifically, the primary circuit includes an EMI circuit or a rectifier bridge circuit.
The surge protection circuit provided by the utility model achieves a super-strong surge protection effect by adopting a multi-stage protection circuit combination, and effectively reduces the residual voltage and residual energy after surge, so that the circuit to be protected is effectively and reliably protected from being damaged by surge, the super-strong surge protection circuit is formed, has high reliability and strong stability, and can be widely applied to various circuits which need surge lightning protection and have low voltage resistance and low current resistance of components of the circuit to be protected.
As shown in fig. 2 and fig. 3, the collected data of the voltage and current in the circuit changing with time is respectively shown under the surge protection circuit provided by the embodiment and the conventional scheme, and it can be found from the figures that by using the improved surge protection circuit, the residual voltage and residual current after the surge can be greatly increased, and the circuit to be protected is effectively protected from being damaged by the surge.
The utility model also provides electrical equipment which comprises the surge protection circuit.
According to the surge protection circuit and the electrical equipment, the super-strong surge protection effect is achieved by adopting the combination of the multi-stage protection circuit, and the residual voltage and the residual energy after the surge are effectively reduced, so that the circuit to be protected is effectively and reliably protected from being damaged by the surge.
Those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than others, combinations of features of different embodiments are meant to be within the scope of the utility model and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (9)
1. The utility model provides a surge protection circuit, its characterized in that, is including connecting gradually the power and treating primary protection circuit and secondary protection circuit between the protection circuit, primary protection circuit and the parallelly connected setting of secondary protection circuit, primary protection circuit is including the protective tube and the first piezo-resistor that set gradually, the protective tube is established ties at power input end, first piezo-resistor connects in parallel at power input end, secondary protection circuit connects at first piezo-resistor and treats between the protection circuit.
2. The surge protection circuit of claim 1, wherein the secondary protection circuit comprises a discharge tube disposed in parallel with the circuit to be protected.
3. The surge protection circuit of claim 2, further comprising a third protection circuit;
the third protection circuit comprises a first thermistor and a second thermistor which are sequentially arranged, the first thermistor is connected with the discharge tube and a connection point of the circuit to be protected, and the second thermistor is connected with the circuit to be protected in parallel.
4. The surge protection circuit of claim 3, wherein the third protection circuit further comprises a second thermistor, the second thermistor being connected between the second varistor and the discharge tube.
5. The surge protection circuit of claim 4, wherein the first thermistor and the second thermistor are NTC resistors.
6. The surge protection circuit of claim 5, further comprising a fourth protection circuit;
the fourth protection circuit comprises a TVS tube, the TVS tube is connected between the second voltage dependent resistor and the circuit to be protected, and the TVS tube is connected with the circuit to be protected in parallel.
7. The surge protection circuit of claim 2, wherein a primary circuit is connected between the first varistor and the discharge tube.
8. The surge protection circuit of claim 7, wherein the primary circuit comprises an EMI circuit or a rectifier bridge circuit.
9. An electrical appliance comprising a surge protection circuit according to any of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121879802.6U CN215681791U (en) | 2021-08-11 | 2021-08-11 | Surge protection circuit and electrical equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121879802.6U CN215681791U (en) | 2021-08-11 | 2021-08-11 | Surge protection circuit and electrical equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215681791U true CN215681791U (en) | 2022-01-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121879802.6U Active CN215681791U (en) | 2021-08-11 | 2021-08-11 | Surge protection circuit and electrical equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215681791U (en) |
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2021
- 2021-08-11 CN CN202121879802.6U patent/CN215681791U/en active Active
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