CN213817586U - Adjustable voltage stabilization protection circuit - Google Patents
Adjustable voltage stabilization protection circuit Download PDFInfo
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- CN213817586U CN213817586U CN202022796226.0U CN202022796226U CN213817586U CN 213817586 U CN213817586 U CN 213817586U CN 202022796226 U CN202022796226 U CN 202022796226U CN 213817586 U CN213817586 U CN 213817586U
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Abstract
The utility model discloses an adjustable steady voltage protection circuit belongs to the steady voltage protection field, include: the power supply comprises an input voltage end, an output voltage end, a first triode, a second triode, a voltage regulator tube and a current limiting branch, wherein the input voltage end is connected with an external power supply; the output voltage end provides output voltage for the integrated circuit; the collector of the first triode is connected with the input voltage end, the emitter of the first triode is connected with the output voltage end, and a second resistor is connected between the base of the first triode and the input voltage end; the collector of the second triode is connected with the base of the first triode; the base electrode of the second triode is connected with a feedback voltage led out from the output voltage end; the voltage regulator tube is controllably connected between the emitter electrode of the second triode and the grounding end. The technical scheme has the following advantages: when the input voltage is too high, the IC circuit can be protected, and the voltage stabilization protection circuit has the advantages of adjustable voltage stabilization value, high response speed, good stability and the like.
Description
Technical Field
The utility model relates to a steady voltage protection field especially relates to an adjustable steady voltage protection circuit.
Background
In the working process of the circuit, the interference signal is inevitably generated under the limitation of switching action, electrostatic action, power grid interference and the like. When high-voltage interference occurs, if the input end of the chip is not connected with a protection circuit, the chip is easy to break down, the chip can be burnt in serious conditions, and along with the increasing complexity of the design structure of the chip, the functions are more and more, the price is more and more expensive, so that the increase of the protection circuit at the input end of the chip is very important.
At present, IC chips (Integrated circuits) having a higher withstand voltage level are generally selected; or a voltage-stabilizing tube is directly connected in parallel with the input end of the IC chip, and when the input voltage is overhigh, the voltage-stabilizing tube breaks down, thereby playing a role in protecting the IC chip; the methods not only bring the problem of re-selection, even the voltage-regulator tube is burnt due to over-power, but also increase the circuit design cost, so that an adjustable voltage-stabilizing protection circuit is urgently needed to be provided, and the adjustable voltage-stabilizing protection circuit has the characteristics of simple circuit, low cost, adjustable output voltage-stabilizing value, stable performance and the like, and overcomes the problems in the prior art.
Disclosure of Invention
Aiming at the problems in the prior art, an adjustable voltage stabilization protection circuit is provided, and the specific technical scheme is as follows:
an adjustable regulated protection circuit comprising:
the input voltage end is connected with an external power supply;
an output voltage terminal for providing an output voltage to an integrated circuit;
the collector of the first triode is connected with the input voltage end, the emitter of the first triode is connected with the output voltage end, and a second resistor is connected between the base of the first triode and the input voltage end;
the collector of the second triode is connected with the base of the first triode; the base electrode of the second triode is connected with a feedback voltage led out from the output voltage end;
the voltage stabilizing tube is controllably connected between the emitting electrode of the second triode and the grounding end;
and the current-limiting branch is connected between the output voltage end and the voltage-stabilizing tube.
Preferably, a first resistor is connected between the collector of the first triode and the input voltage terminal.
Preferably, a first capacitor is connected between the base of the first triode and the ground terminal.
Preferably, the method further comprises the following steps:
one end of the second capacitor is connected with the emitting electrode of the first triode, and the other end of the second capacitor is connected with the base electrode of the second triode.
Preferably, the current limiting branch is composed of a third resistor.
Preferably, a fourth resistor and a fifth resistor are sequentially connected between the output voltage terminal and the ground terminal;
and the base electrode of the second triode is connected between the fourth resistor and the fifth resistor.
Preferably, the feedback voltage is adjusted by changing a resistance ratio of the fourth resistor and the fifth resistor.
Preferably, the second resistor is connected in parallel between the collector and the base of the first triode, and the first triode and the second resistor are equivalent to a voltage follower.
Preferably, in a first working state, the voltage regulator tube is broken down, the voltage regulator tube and the current limiting branch circuit form a reference voltage source, and a reference voltage value of the reference voltage source is equal to a voltage stabilizing value of the voltage regulator tube.
This technical scheme has following advantage or beneficial effect:
the technical scheme provides an adjustable voltage-stabilizing protection circuit which is connected in series between a power supply and an IC circuit, can play a role of protecting the IC circuit when the input voltage is too high, and has the advantages of adjustable voltage-stabilizing value, high response speed, simple and easy circuit realization, good stability, high cost performance and the like.
Drawings
Fig. 1 is a block diagram of an adjustable voltage-stabilizing protection circuit according to the present invention;
fig. 2 is a schematic circuit diagram of the adjustable voltage stabilizing protection circuit of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be further described with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.
To solve the above problems in the prior art, an adjustable voltage stabilization protection circuit is provided, which belongs to the field of voltage stabilization protection, and as shown in fig. 1 and fig. 2, the voltage stabilization protection circuit 2 includes:
the input voltage end is connected with an external power supply 1, and the input voltage of the input voltage end is less than 40V;
an output voltage terminal for providing an output voltage to an integrated circuit 3, the output voltage of the output voltage terminal is less than 30V, and the output current is less than 100 mA;
a first triode Q1, wherein the collector of the first triode Q1 is connected with the input voltage end, the emitter of the first triode Q1 is connected with the output voltage end, and a second resistor R2 is connected between the base of the first triode Q1 and the input voltage end;
a second triode Q2, wherein the collector of the second triode Q2 is connected with the base of the first triode Q1; the base electrode of the second triode Q2 is connected with a feedback voltage led out from the output voltage end;
a voltage regulator D1 controllably connected between the emitter and ground of the second transistor Q2;
and the current limiting branch is connected between the output voltage end and the voltage regulator tube D1.
Through the technical scheme, when the input voltage Vin (namely the power supply voltage) of the input voltage end is normal, the emitter of the second triode Q2 is disconnected, the second triode Q2 does not work, the voltage stabilizing diode D1 is not broken, a second resistor R2 is connected in parallel between the collector and the base of the first triode Q1, the second resistor R2 is equivalent to a voltage follower, the output voltage Vout of the output voltage end is equal to the input voltage Vin minus the tube voltage drop V of the first triode Q1ce1And a voltage division V of the first resistor R1r1。
In a preferred embodiment, a first resistor R1 is connected between the collector of the first transistor Q1 and the input voltage terminal.
In a preferred embodiment, a first capacitor C1 is connected between the base of the first transistor Q1 and ground.
In a preferred embodiment, the method further comprises:
one end of a second capacitor C2, one end of a second capacitor C2 is connected to the emitter of the first transistor Q1, and the other end of the second capacitor C2 is connected to the base of the second transistor Q2.
In a preferred embodiment, the current limiting branch is formed by a third resistor R3.
In a preferred embodiment, a fourth resistor R4 and a fifth resistor R5 are connected between the output voltage terminal and the ground terminal in sequence;
the base of the second transistor Q2 is connected between the fourth resistor R4 and the fifth resistor R5.
Further, in a preferred embodiment, the feedback voltage can be adjusted by the ratio of the resistances of the fourth resistor R4 and the fifth resistor R5, and the resistances of the fourth resistor R4 and the fifth resistor R5 can be increased or decreased respectively according to the requirements of the actual circuit design to set a suitable ratio of the resistances.
Further, the voltage stabilizing value of the voltage stabilizing tube D1 is [2.2V, 5.1V ].
Furthermore, a second resistor R2 is connected in parallel between the collector and the base of the first transistor Q1, and the first transistor Q1 and the second resistor R2 are equivalent to a voltage follower.
Further, in a preferred embodiment, the resistance range of the first resistor R1 is [10 Ω, 500 Ω ], and the package size of the first resistor R1 is 1210 or 1206; the resistance ranges of the second resistor R2, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 are [1000 Ω, 10000 Ω ], and the packaging specifications of the second resistor R2, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 are 0805 or 1206 respectively.
Further, in a preferred embodiment, the first capacitor C1 and the second capacitor C1 both have a capacitance of [10nF, 1uF ], and the first capacitor C1 and the second capacitor C2 have a package size of 0805 or 0603, respectively.
Further, in a preferred embodiment, the first transistor Q1 and the second transistor Q2 are both NPN transistors Q, and preferably, both the first transistor Q1 and the second transistor Q2 may be NPN transistors Q of type BC 817-40Q-7-F.
By adopting the technical scheme, when the input voltage Vin is overhigh (exceeds a normal value range), the second triode Q2 works normally, the voltage regulator tube D1 is broken down, and the voltage regulator tube D1 and the third resistor R3 form a reference voltage source Vd1Reference voltage value V of reference voltage sourced1Equal to the regulated voltage of the regulator tube D1, the fourth resistor R4 and the fifth resistor R5 divide the output voltage Vout, and then the divided voltage V of the fifth resistor R5r5Vout/(R4+ R5) is added to the base of the second transistor Q2 and the base voltage V of the second transistor Q2r5Reference voltage V to emitterd1Comparing;
when the output voltage Vout increases, the base voltage V of the second transistor Q2r5Reference voltage V to emitterd1The voltage difference of the second transistor Q2 is increased, the collector current of the second transistor Q2 is increased, the current flowing through the second resistor R2 is increased, and the divided voltage of the second resistor R2 is increased in combination with ohm's law, so that the voltage difference between the base and emitter of the first transistor Q1 is reduced, and the base current I of the first transistor Q1 is reducedb1The voltage difference between the collector and the emitter of the first triode Q1 is reduced, so that the output voltage is reduced and stabilizedAnd 4, the output voltage protection circuit.
In the above preferred embodiment, the feedback voltage can be adjusted by changing the ratio of the resistances of the fourth resistor R4 and the fifth resistor R5. When the input voltage Vin is not changed, the resistance ratio of the fourth resistor R4 and the fifth resistor R5 is adjusted by reducing the resistance of the fifth resistor R5, and the base voltage V of the second transistor Q2 is obtainedr5When the base-emitter voltage of the second transistor Q2 is reduced, the collector current of the second transistor Q2 is reduced, the current flowing through the second resistor R2 is reduced, the divided voltage of the second resistor R2 is reduced, the base-emitter voltage of the first transistor Q1 is increased, and the base current I of the first transistor Q1 is reducedb1The voltage drop Vce1 of the first triode Q1 is increased, the output voltage is increased due to the unchanged input voltage Vin, so that the output voltage stabilizing value is changed, wherein the second capacitor C2 is used as an accelerating capacitor in the circuit, when the output voltage Vout changes, the second capacitor C2 directly adds the fluctuating voltage to the base of the second triode Q2 due to the characteristic that the voltage at two ends of the capacitor cannot suddenly change, so that the second triode Q2 makes adjustment rapidly, and the response speed of the protection circuit is improved.
This technical scheme has following advantage or beneficial effect:
the technical scheme provides an adjustable voltage-stabilizing protection circuit which is connected in series between a power supply and an IC circuit, can play a role of protecting the IC circuit when the input voltage is too high, and has the advantages of adjustable voltage-stabilizing value, high response speed, simple and easy circuit realization, good stability, high cost performance and the like.
The above description is only an example of the preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and those skilled in the art should be able to realize the equivalent alternatives and obvious variations of the present invention.
Claims (9)
1. An adjustable regulated protection circuit, comprising:
the input voltage end is connected with an external power supply;
an output voltage terminal for providing an output voltage to an integrated circuit;
the collector of the first triode is connected with the input voltage end, the emitter of the first triode is connected with the output voltage end, and a second resistor is connected between the base of the first triode and the input voltage end;
the collector of the second triode is connected with the base of the first triode; the base electrode of the second triode is connected with a feedback voltage led out from the output voltage end;
the voltage stabilizing tube is controllably connected between the emitting electrode of the second triode and the grounding end;
and the current-limiting branch is connected between the output voltage end and the voltage-stabilizing tube.
2. The adjustable regulated protection circuit of claim 1 wherein a first resistor is coupled between the collector of said first transistor and said input voltage terminal.
3. The adjustable regulated protection circuit of claim 1 wherein a first capacitor is connected between the base of said first transistor and said ground terminal.
4. The adjustable regulated protection circuit of claim 1, further comprising:
one end of the second capacitor is connected with the emitting electrode of the first triode, and the other end of the second capacitor is connected with the base electrode of the second triode.
5. The adjustable regulated protection circuit of claim 1 wherein said current limiting branch is comprised of a third resistor.
6. The adjustable voltage-stabilizing protection circuit according to claim 1, wherein a fourth resistor and a fifth resistor are connected between the output voltage terminal and the ground terminal in sequence;
and the base electrode of the second triode is connected between the fourth resistor and the fifth resistor.
7. The adjustable regulated protection circuit of claim 6 wherein said feedback voltage is adjusted by changing the ratio of the resistances of said fourth resistor and said fifth resistor.
8. The adjustable regulated protection circuit of claim 1 wherein said second resistor is connected in parallel between the collector and the base of said first transistor, said first transistor and said second resistor acting as a voltage follower.
9. An adjustable voltage regulation protection circuit as claimed in claim 1 wherein in the first operating condition, the stabilivolt is broken down, the stabilivolt and the current limiting branch form a reference voltage source, the reference voltage value of the reference voltage source being equal to the voltage regulation value of the stabilivolt.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022796226.0U CN213817586U (en) | 2020-11-27 | 2020-11-27 | Adjustable voltage stabilization protection circuit |
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| CN202022796226.0U CN213817586U (en) | 2020-11-27 | 2020-11-27 | Adjustable voltage stabilization protection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118192739A (en) * | 2024-05-09 | 2024-06-14 | 深圳市华芯控股有限公司 | Method and device for realizing adjustable negative voltage stabilizing circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118192739A (en) * | 2024-05-09 | 2024-06-14 | 深圳市华芯控股有限公司 | Method and device for realizing adjustable negative voltage stabilizing circuit |
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