CN219287144U - Power supply protection circuit - Google Patents
Power supply protection circuit Download PDFInfo
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- CN219287144U CN219287144U CN202320219914.1U CN202320219914U CN219287144U CN 219287144 U CN219287144 U CN 219287144U CN 202320219914 U CN202320219914 U CN 202320219914U CN 219287144 U CN219287144 U CN 219287144U
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Abstract
The utility model provides a power supply protection circuit which comprises a first triode, a second triode, a third triode, a fourth triode and a voltage stabilizer, wherein the collector electrode of the first triode is connected with an input power supply and the base electrode of the second triode, and the base electrode of the first triode is connected with the collector electrode of the second triode and one end of a charging capacitor; the base electrode of the second triode is also connected with the positive electrode of a diode, the negative electrode of the diode is connected with the output end of the voltage stabilizer, and the collector electrode of the second triode is also connected with an input power supply and the emitter electrode of the fourth triode; the base electrode of the third triode is connected between the collector electrode of the first triode and the base electrode of the second triode, and the collector electrode of the third triode is connected with the base electrode of the fourth triode; the collector of the fourth triode is connected with the input end of the voltage stabilizer. The circuit is arranged between the input power supply and the voltage stabilizer, and when short circuit occurs, the power supply current and voltage to the voltage stabilizer can be immediately stopped, so that the voltage stabilizer is prevented from being damaged.
Description
Technical Field
The utility model relates to the field of power supplies, in particular to a power supply protection circuit.
Background
In power circuits, it is often desirable to use voltage regulators, such as 78 series voltage regulators. The voltage regulator is easily damaged when the power supply circuit is short-circuited. When the voltage stabilizer is damaged, the power circuit is repaired, and only the damaged voltage stabilizer can be replaced, so that the replacement process is complex and cumbersome, and quite inconvenient. Therefore, it is necessary to provide a protection circuit for protecting the voltage regulator from damage when the circuit is short-circuited.
Disclosure of Invention
The utility model aims to provide a power supply protection circuit.
In order to achieve the above purpose, the following technical scheme is adopted:
the power supply protection circuit comprises a first triode, a second triode, a third triode, a fourth triode and a voltage stabilizer, wherein the collector electrode of the first triode is connected with an input power supply and the base electrode of the second triode, the base electrode of the first triode is connected with the collector electrode of the second triode and one end of a charging capacitor, and the emitter electrode of the first triode and the other end of the charging capacitor are grounded; the base electrode of the second triode is also connected with the positive electrode of a diode, the negative electrode of the diode is connected with the output end of the voltage stabilizer, the collector electrode of the second triode is also connected with an input power supply and the emitter electrode of the fourth triode, and the emitter electrode of the second triode is grounded; the base electrode of the third triode is connected between the collector electrode of the first triode and the base electrode of the second triode, the collector electrode of the third triode is connected with the base electrode of the fourth triode, and the emitter electrode of the third triode is grounded; the collector electrode of the fourth triode is connected with the input end of the voltage stabilizer; a first resistor is arranged between the collector electrode of the first triode and the input power supply, a second resistor is arranged between the base electrode of the first triode and the collector electrode of the second triode, and a third resistor is arranged between the collector electrode of the first triode and the base electrode of the second triode; a fifth resistor is arranged between the collector of the second triode and the fourth triode, a fourth resistor is arranged between the base of the third triode and the collector of the first triode and the base of the second triode, and a sixth resistor is arranged between the collector of the third triode and the fourth triode.
Further, the fourth triode is a darlington triode.
Further, the collector of the second triode is also connected with one end of a reset switch, and the other end of the reset switch is grounded.
By adopting the scheme, the utility model has the beneficial effects that:
when short circuit occurs, the circuit can immediately stop the supply current and voltage to the voltage stabilizer, thereby preventing the voltage stabilizer from being damaged. The whole circuit is simple and safe, a complex protection chip is not needed, and circuit protection is realized at low cost.
Drawings
Fig. 1 is a schematic diagram of a power protection circuit according to an embodiment of the utility model.
Detailed Description
Exemplary embodiments that embody features and advantages of the present utility model will be described in detail in the following description. It will be understood that the utility model is capable of various modifications in various embodiments, all without departing from the scope of the utility model, and that the description and illustrations herein are intended to be by way of illustration only and not to be construed as limiting the utility model.
As shown in fig. 1, a power protection circuit includes a first triode Q1, a second triode Q2, a third triode Q3, a fourth triode Q4, and a voltage regulator U1, wherein a collector of the first triode Q1 is connected to an input power supply and a base of the second triode Q2, a base of the first triode Q is connected to a collector of the second triode Q2 and one end of a charging capacitor C1, and an emitter of the first triode Q and the other end of the charging capacitor C1 are grounded; the base electrode of the second triode Q2 is also connected with the positive electrode of a diode D1, the negative electrode of the diode D1 is connected with the output end of a voltage stabilizer U1, the collector electrode of the second triode Q2 is also connected with an input power supply and the emitter electrode of a fourth triode Q4, and the emitter electrode is grounded; the base electrode of the third triode Q3 is connected between the collector electrode of the first triode Q1 and the base electrode of the second triode Q2, the collector electrode of the third triode Q3 is connected with the base electrode of the fourth triode Q4, and the emitter electrode of the third triode Q4 is grounded; the collector electrode of the fourth triode Q4 is connected to the input end of the voltage stabilizer U1; in the first triode Q1, a first resistor R1 is arranged between the collector and the input power supply, a second resistor R2 is arranged between the base and the collector of the second triode Q2, and a third resistor R3 is arranged between the collector and the base of the second triode Q2; a fifth resistor R5 is arranged between the collector of the second triode Q2 and the fourth triode Q4, a fourth resistor R4 is arranged between the base of the third triode Q3 and the collector of the first triode Q1 and the base of the second triode Q2, and a sixth resistor R6 is arranged between the collector of the third triode Q3 and the fourth triode Q4.
The fourth transistor Q4 is a darlington transistor.
The collector of the second triode Q2 is also connected with one end of a reset switch S1, and the other end of the reset switch S1 is grounded.
Wherein, when the power input voltage is input, the first triode Q1 and the second triode Q2 are both in the flip-flop circuit. Firstly, the second triode Q2 is operated, but the first triode Q1 is not operated, because of the charging capacitor C1, the charging capacitor C1 is charged when the first triode Q1 is turned on, so that the first triode Q1 is not triggered to be turned on, meanwhile, the collector of the first triode Q1 biases the base of the third triode Q3 through the fourth resistor R4, the third triode Q3 is operated, and then the fourth triode Q4 is also operated, the voltage stabilizer U1 is operated normally, and the output voltage supplies power to the load.
When a short circuit occurs, the diode D1 plays a role of grounding, so that the base voltage of the second triode Q2 is reduced, the second triode Q2 is not conducted, the first triode Q1 is conducted, the third triode Q3, the fourth triode Q4 and the voltage stabilizer U1 are not conducted, and the voltage stabilizer U1 does not work at the moment, so that damage is not caused.
After the short circuit problem is solved, the reset switch S1 is pressed, so that the reset circuit can be operated again.
The circuit is arranged between an input power supply and the voltage stabilizer, and when a short circuit occurs, the power supply current and voltage to the voltage stabilizer can be immediately stopped, so that the voltage stabilizer is prevented from being damaged. The whole circuit is simple and safe, does not need a complex protection chip, and realizes circuit protection at low cost
While the present disclosure has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration rather than of limitation. As the present disclosure may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.
Claims (3)
1. The power supply protection circuit is characterized by comprising a first triode, a second triode, a third triode, a fourth triode and a voltage stabilizer, wherein the collector electrode of the first triode is connected with an input power supply and the base electrode of the second triode, the base electrode of the first triode is connected with the collector electrode of the second triode and one end of a charging capacitor, and the emitter electrode of the first triode and the other end of the charging capacitor are grounded; the base electrode of the second triode is also connected with the positive electrode of a diode, the negative electrode of the diode is connected with the output end of the voltage stabilizer, the collector electrode of the second triode is also connected with an input power supply and the emitter electrode of the fourth triode, and the emitter electrode of the second triode is grounded; the base electrode of the third triode is connected between the collector electrode of the first triode and the base electrode of the second triode, the collector electrode of the third triode is connected with the base electrode of the fourth triode, and the emitter electrode of the third triode is grounded; the collector electrode of the fourth triode is connected with the input end of the voltage stabilizer; a first resistor is arranged between the collector electrode of the first triode and the input power supply, a second resistor is arranged between the base electrode of the first triode and the collector electrode of the second triode, and a third resistor is arranged between the collector electrode of the first triode and the base electrode of the second triode; a fifth resistor is arranged between the collector of the second triode and the fourth triode, a fourth resistor is arranged between the base of the third triode and the collector of the first triode and the base of the second triode, and a sixth resistor is arranged between the collector of the third triode and the fourth triode.
2. The power protection circuit of claim 1, wherein the fourth transistor is a darlington transistor.
3. The power protection circuit of claim 1, wherein the collector of the second transistor is further connected to one end of a reset switch, and the other end of the reset switch is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320219914.1U CN219287144U (en) | 2023-01-30 | 2023-01-30 | Power supply protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320219914.1U CN219287144U (en) | 2023-01-30 | 2023-01-30 | Power supply protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219287144U true CN219287144U (en) | 2023-06-30 |
Family
ID=86911755
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320219914.1U Active CN219287144U (en) | 2023-01-30 | 2023-01-30 | Power supply protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219287144U (en) |
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2023
- 2023-01-30 CN CN202320219914.1U patent/CN219287144U/en active Active
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