CN216413923U - Overvoltage protection circuit - Google Patents
Overvoltage protection circuit Download PDFInfo
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- CN216413923U CN216413923U CN202123021387.3U CN202123021387U CN216413923U CN 216413923 U CN216413923 U CN 216413923U CN 202123021387 U CN202123021387 U CN 202123021387U CN 216413923 U CN216413923 U CN 216413923U
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- power supply
- output power
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- protection circuit
- overvoltage protection
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Abstract
The utility model discloses an overvoltage protection circuit, comprising: the power supply comprises a power supply anode, a power supply cathode, an output power anode, an output power cathode, a fuse, a current-limiting resistor, a filter capacitor and a unipolar transient suppression diode, wherein one end of the fuse is connected with the power supply anode, the other end of the fuse is connected with the output power anode, one end of the current-limiting resistor is connected with the power supply cathode, the other end of the current-limiting resistor is connected with the output power cathode, the cathode of the unipolar transient suppression diode is connected with the output power anode, the anode of the unipolar transient suppression diode is connected with the output power cathode, the corresponding end of the filter capacitor is connected with the output power anode, and the other end of the filter capacitor is connected with the output power cathode. The overvoltage protection circuit is mainly used as an output circuit of a direct-current stabilized power supply and is mainly used for protecting chips and some important electrical elements.
Description
Technical Field
The utility model relates to an overvoltage protection circuit, in particular to an overvoltage protection circuit of a power supply circuit.
Background
At present, the power supply supplies power directly to loads in the circuit. In the actual working process, once the power supply suddenly becomes large due to lightning strike, static electricity or other transient high voltage, the malfunction of a sensitive device, the damage of important parts or expensive devices in the circuit, even the damage of any active device related to the power supply can be caused, and finally the circuit can not be repaired to be scrapped.
SUMMERY OF THE UTILITY MODEL
The technical problem to be solved by the utility model is as follows: an overvoltage protection circuit is provided that prevents damage to a load and related devices due to overvoltage.
In order to solve the technical problems, the technical scheme adopted by the utility model is as follows: an overvoltage protection circuit comprising: the power supply comprises a power supply anode, a power supply cathode, an output power anode, an output power cathode, a fuse, a current-limiting resistor, a filter capacitor and a unipolar transient suppression diode, wherein one end of the fuse is connected with the power supply anode, the other end of the fuse is connected with the output power anode, one end of the current-limiting resistor is connected with the power supply cathode, the other end of the current-limiting resistor is connected with the output power cathode, the cathode of the unipolar transient suppression diode is connected with the output power anode, the anode of the unipolar transient suppression diode is connected with the output power cathode, the corresponding end of the filter capacitor is connected with the output power anode, and the other end of the filter capacitor is connected with the output power cathode.
Preferably, in the overvoltage protection circuit, the fuse is a self-recovery fuse.
As a preferable scheme, in the overvoltage protection circuit, it is provided that: the output voltage of the power supply is VCC, the reverse voltage value of the transient suppression diode is VD1, the maximum peak pulse current of the transient suppression diode is Ipp, and the maximum action current of the self-recovery fuse is IF 1;
then: the resistance value of the current limiting resistor is less than or equal to (VCC-VD1)/IF1, wherein (VCC-VD1)/Ipp is less than or equal to.
Preferably, in the overvoltage protection circuit, the filter capacitor is an electrolytic capacitor.
The utility model has the beneficial effects that: the overvoltage protection circuit is simple in structure and good in stability; in the practical use process, all devices in the circuit of the overvoltage protection circuit and all devices in the load, especially chips and some important electrical components can be effectively protected, so that the overvoltage protection circuit cannot be damaged due to overvoltage.
Drawings
Fig. 1 is an electrical schematic of the overvoltage protection circuit of the present invention.
Detailed Description
An embodiment of an overvoltage protection circuit according to the present invention is described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the overvoltage protection circuit according to the present invention includes: a power supply anode VCC, a power supply cathode GND, an output power anode P, an output power cathode M, a self-recovery fuse F1, a current-limiting resistor R1, an electrolytic capacitor C1 as a filter capacitor, and a unipolar transient suppression diode D1, wherein one end of the self-recovery fuse F1 is connected with the power supply anode VCC, the other end of the self-recovery fuse F1 is connected with the output power anode P, one end of the current-limiting resistor R1 is connected with the power supply cathode GND, the other end of the current-limiting resistor R1 is connected with the output power cathode M, the cathode of the unipolar transient suppression diode D1 is connected with the anode P of the output power supply, the anode of the unipolar transient suppression diode D is connected with the cathode M of the output power supply, the anode of the electrolytic capacitor C1 is connected with the anode P of the output power supply, and the other end of the electrolytic capacitor C1 is connected with the cathode M of the output power supply.
The working principle of the utility model is as follows: suppose that: the power supply VCC is 14V (the output voltage of the anode of the power supply is 14V), the electrolytic capacitor C1 is 100uF/25V, the self-recovery fuse F1 is BNM02007A000(0.2A/30V, maximum voltage) with the model of BETTEROperating current I18A, 20ms of action time), the type of the transient suppression diode D1 is selected as follows: SMAJ15A of LITTELFFUSE (reverse voltage Vr value of 15V, maximum peak pulse current Ipp value of 16.4A), and normal operating current I of output power supply2Is 0.2A; under normal conditions of the output power supply, the self-recovery fuse F1 presents low resistance, and the transient suppression diode D1 is also in an inactive state.
When the power supply VCC reaches 30V due to transient and the transient time is millisecond or even microsecond, the transient suppression diode D1 acts to clamp the output power supply to 15V, and because the transient suppression diode D1 acts for microsecond, the transient voltage cannot be reflected to the supplied circuit at the rear stage because the voltage of the electrolytic capacitor cannot be suddenly changed, thereby achieving the protection function.
When the power supply VCC reaches 30V due to a transient and the transient time is in the order of hundreds of milliseconds or even seconds, the transient suppression diode D1 acts to clamp the output power to 15V, with a voltage of 15V applied across the current limiting resistor R1, according to ((VCC-VD 1)/Ipp. ltoreq.R 1. ltoreq. VCC-VD1)/IF1), i.e., ((30V-15V)/16.4A. ltoreq. R1. ltoreq. 30V-15V)/8A, then: the value of the current limiting resistor R1 ranges from 0.914 to 1.875 Ω, because: first, since the maximum peak pulse current Ipp of the transient suppression diode D1 is 16.4A, if a resistance value below 0.914 Ω is selected: 15V across the current limiting resistor R1 will produce a pulse current in excess of 16.4A, potentially damaging the transient suppression diode D1; secondly, as the larger the current of the self-recovery fuse F1 is, the shorter the action time is, the maximum action current and time are 8A/20ms, the resistance value of the current-limiting resistor R1 is lower than 1.875 Ω, and 15V added to the current-limiting resistor R1 will generate pulse current higher than 8A, so that the protection can be faster) according to the volt-ampere characteristic, the current flowing through F1, D1 and R1 will be reduced and tend to zero, thereby stabilizing the output power supply at 15V and protecting the transient suppression diode D1 and the current-limiting resistor R1 from being damaged.
In summary, the present invention is only a preferred embodiment, and not intended to limit the scope of the utility model, and all equivalent changes and modifications made in the shape, structure, characteristics and spirit of the present invention described in the claims should be included in the scope of the present invention.
Claims (4)
1. An overvoltage protection circuit comprising: the power supply positive pole, power supply negative pole, output power positive pole and output power negative pole, its characterized in that: the overvoltage protection circuit further comprises: the current-limiting circuit comprises a fuse, a current-limiting resistor, a filter capacitor and a unipolar transient suppression diode, wherein one end of the fuse is connected with the positive electrode of a power supply, the other end of the fuse is connected with the positive electrode of an output power supply, one end of the current-limiting resistor is connected with the negative electrode of the power supply, the other end of the current-limiting resistor is connected with the negative electrode of the output power supply, the cathode of the unipolar transient suppression diode is connected with the positive electrode of the output power supply, the anode of the unipolar transient suppression diode is connected with the negative electrode of the output power supply, the corresponding end of the filter capacitor is connected with the positive electrode of the output power supply, and the other end of the filter capacitor is connected with the negative electrode of the output power supply.
2. The overvoltage protection circuit of claim 1, wherein said fuse is a self-healing fuse.
3. The overvoltage protection circuit of claim 2, wherein: the output voltage of the power supply is VCC, the reverse voltage value of the transient suppression diode is VD1, the maximum peak pulse current of the transient suppression diode is Ipp, and the maximum action current of the self-recovery fuse is IF 1;
then: the resistance value of the current limiting resistor is less than or equal to (VCC-VD1)/IF1, wherein (VCC-VD1)/Ipp is less than or equal to.
4. The overvoltage protection circuit of any one of claims 1 to 3, wherein said filter capacitor is an electrolytic capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123021387.3U CN216413923U (en) | 2021-12-03 | 2021-12-03 | Overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123021387.3U CN216413923U (en) | 2021-12-03 | 2021-12-03 | Overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216413923U true CN216413923U (en) | 2022-04-29 |
Family
ID=81304616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123021387.3U Active CN216413923U (en) | 2021-12-03 | 2021-12-03 | Overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216413923U (en) |
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2021
- 2021-12-03 CN CN202123021387.3U patent/CN216413923U/en active Active
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