CN202797952U - Overvoltage protection circuit - Google Patents
Overvoltage protection circuit Download PDFInfo
- Publication number
- CN202797952U CN202797952U CN 201220488671 CN201220488671U CN202797952U CN 202797952 U CN202797952 U CN 202797952U CN 201220488671 CN201220488671 CN 201220488671 CN 201220488671 U CN201220488671 U CN 201220488671U CN 202797952 U CN202797952 U CN 202797952U
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- bipolar transistor
- resistance
- resistor
- circuit
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Abstract
The utility model discloses an overvoltage protection circuit. An input end of the circuit is connected with a source of a first bipolar transistor and a source of a second bipolar transistor, is connected with a base of the first bipolar transistor and a source of a third bipolar transistor through a sixth resistor and is connected with a base of the second bipolar transistor through a fourth resistor, an anode of a shunt regulator is grounded, a cathode of the shunt regulator is connected with the base of the second bipolar transistor through a fifth resistor and is connected with the input end through a second resistor, a reference voltage input end is grounded through a third resistor and is connected with the input end through a first resistor, an output end is connected with a collector of the first bipolar transistor, a collector of the third bipolar transistor is grounded through an eighth resistor, and a base of the third bipolar transistor and a collector of the second bipolar transistor are grounded through a seventh resistor. The circuit has the advantages that the circuit structure is simple, required elements and nodes are few, the cost and the power consumption can be reduced, and the defective pixel risk can be reduced.
Description
Technical field
The utility model relates to a kind of overvoltage crowbar that is applicable to the power supply input.
Background technology
The needed voltage of portable type electronic product is generally lower, is 1.5V, 2.5V, 3.3V or 5V voltage generally speaking.In circuit, since the factor such as circuit signal is interfered, short circuit or supply power voltage are unstable, the situation that may cause voltage to raise suddenly, and too high voltage can affect the performance of circuit, burns out in addition the risk of circuit.
Overvoltage crowbar is the necessary circuitry that solves the problem of overvoltage, the complicated structure of the circuit of prior art, and required device and node are more, and device causes cost and power consumption higher more, and node is more to cause having a big risk of bad point.
The utility model content
Goal of the invention of the present utility model is: for the problem of above-mentioned existence, provide a kind of overvoltage crowbar of power supply input.
The technical solution adopted in the utility model is such: a kind of overvoltage crowbar, comprise input and output, and this circuit also comprises the bipolar transistor of three positive-negative-positives, a shunt regulator and eight resistance.
Described input: be connected to the source electrode of the first bipolar transistor and the source electrode of the second bipolar transistor, be connected to the base stage of the first bipolar transistor and the source electrode of the 3rd bipolar transistor by the 6th resistance, be connected to the base stage of the second bipolar transistor by the 4th resistance; Described shunt regulator: plus earth, negative electrode is connected to the base stage of the second bipolar transistor and is connected to input by the second resistance by the 5th resistance, and reference voltage input terminal is connected to input by the 3rd grounding through resistance and by the first resistance; Described output is connected to the collector electrode of the first bipolar transistor; The collector electrode of described the 3rd bipolar transistor is by the 8th grounding through resistance, and the collector electrode of base stage and the second bipolar transistor is by the 7th grounding through resistance.
In above-mentioned circuit, described the second bipolar transistor is the identical bipolar transistor of parameter with the 3rd bipolar transistor.
In sum, owing to adopted technique scheme, the beneficial effects of the utility model are: circuit structure is simple, and required device and node are less, reduce cost and power consumption, and reduces the bad point risk.
Description of drawings
Fig. 1 is the circuit theory diagrams of the utility model overvoltage crowbar.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in detail.
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explaining the utility model, and be not used in restriction the utility model.
As shown in Figure 1, be the circuit theory diagrams of the utility model overvoltage crowbar.
A kind of overvoltage crowbar of the present utility model comprises input IN and output OUT, and this circuit also comprises the bipolar transistor Q1～Q3 of three positive-negative-positives, a shunt regulator A1 and eight resistance R 1～R8.
Do into a detailed description below in conjunction with the annexation between above-mentioned each electronic devices and components of 1 pair of the utility model of accompanying drawing: described input IN: be connected to the source electrode of the first bipolar transistor Q1 and the source electrode of the second bipolar transistor Q2, be connected to the base stage of the first bipolar transistor Q1 and the source electrode of the 3rd bipolar transistor Q3 by the 6th resistance R 6, be connected to the base stage of the second bipolar transistor Q2 by the 4th resistance R 4; Described shunt regulator A1: plus earth GND, negative electrode is connected to the base stage of the second bipolar transistor Q2 and is connected to input IN by the second resistance R 2 by the 5th resistance, and reference voltage input terminal is connected to input IN by the 3rd resistance R 3 ground connection GND and by the first resistance R 1; Described output OUT is connected to the collector electrode of the first bipolar transistor Q1; The collector electrode of described the 3rd bipolar transistor Q3 is by the 8th resistance R 8 ground connection GND, and the collector electrode of base stage and the second bipolar transistor Q2 is by the 7th resistance R 7 ground connection GND.
In the above-mentioned circuit of the utility model, described the second bipolar transistor Q2 is the identical bipolar transistor of parameter with the 3rd bipolar transistor Q3.
The above only is preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of within spirit of the present utility model and principle, doing, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.
Claims (2)
1. an overvoltage crowbar comprises input (IN) and output (OUT), it is characterized in that, also comprises the bipolar transistor (Q1, Q2, Q3), a shunt regulator (A1) of three positive-negative-positives and eight resistance (R1～R8);
Described input (IN): be connected to the source electrode of the first bipolar transistor (Q1) and the source electrode of the second bipolar transistor (Q2), be connected to the base stage of the first bipolar transistor (Q1) and the source electrode of the 3rd bipolar transistor (Q3) by the 6th resistance (R6), be connected to the base stage of the second bipolar transistor (Q2) by the 4th resistance (R4);
Described shunt regulator (A1): plus earth (GND), negative electrode is connected to the base stage of the second bipolar transistor (Q2) and is connected to input (IN) by the second resistance (R2) by the 5th resistance, and reference voltage input terminal is by the 3rd resistance (R3) ground connection (GND) and be connected to input (IN) by the first resistance (R1);
Output (OUT) is connected to the collector electrode of the first bipolar transistor (Q1);
The collector electrode of the 3rd bipolar transistor (Q3) is by the 8th resistance (R8) ground connection (GND), and the collector electrode of base stage and the second bipolar transistor (Q2) is by the 7th resistance (R7) ground connection (GND).
2. overvoltage crowbar according to claim 1 is characterized in that, described the second bipolar transistor (Q2) is the identical bipolar transistor of parameter with the 3rd bipolar transistor (Q3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220488671 CN202797952U (en) | 2012-09-24 | 2012-09-24 | Overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220488671 CN202797952U (en) | 2012-09-24 | 2012-09-24 | Overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202797952U true CN202797952U (en) | 2013-03-13 |
Family
ID=47825128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220488671 Expired - Fee Related CN202797952U (en) | 2012-09-24 | 2012-09-24 | Overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202797952U (en) |
-
2012
- 2012-09-24 CN CN 201220488671 patent/CN202797952U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130313 Termination date: 20130924 |