CN202586291U - Overload protection circuit - Google Patents
Overload protection circuit Download PDFInfo
- Publication number
- CN202586291U CN202586291U CN 201220201801 CN201220201801U CN202586291U CN 202586291 U CN202586291 U CN 202586291U CN 201220201801 CN201220201801 CN 201220201801 CN 201220201801 U CN201220201801 U CN 201220201801U CN 202586291 U CN202586291 U CN 202586291U
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- China
- Prior art keywords
- triode
- resistance
- collector electrode
- boost converter
- current mode
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- Expired - Lifetime
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Abstract
The utility model discloses an overload protection circuit. The overload protection circuit is characterized in that a base electrode of a first triode is also connected with a collector electrode of a second triode, an emitter electrode of the second triode is connected to a power supply, a base electrode of the second triode is connected with a collector electrode of the first triode through a second resistor, the base electrode of the second triode is connected with a source electrode of a field effect transistor, a drain electrode of the field effect transistor is connected with the power supply, a grid electrode of the field effect transistor is connected with an output terminal of a control circuit through a capacitor, an input terminal of the control circuit is connected with one end of a third resistor, the other end of the third resistor is connected with one end of a fifth resistor, the other end of the fifth resistor is connected to the ground, the other end of the third resistor is also connected with one end of a fourth resistor, and the other end of the fourth resistor is connected with the collector electrode of the first triode. The overload protection circuit has the advantages of simple circuit structure, reliable function and low circuit cost.
Description
Technical field
The utility model relates to circuit design field, specifically a kind of overload protecting circuit.
Background technology
The tradition booster circuit starts moment and causes overload easily, the long electronic chip that burns easily of overload time, and the design of traditional voltage protective circuit is more loaded down with trivial details, uses the device price comparison high.
Summary of the invention
The utility model purpose is to provide a kind of overload protecting circuit, and the protection device is not damaged.
In order to realize this purpose, the technical scheme of the utility model is following: a kind of overload protecting circuit comprises first triode; The emitter of this first triode connects power supply, and collector electrode connects load, and base stage is through first grounding through resistance; The base stage that it is characterized in that this first triode also is connected with the collector electrode of second triode, and the emitter of this second triode connects power supply, and the base stage of second triode is connected with the collector electrode of first triode through second resistance; The base stage of this second triode is connected with the source electrode of FET; The drain electrode of this FET connects power supply, and the grid of this FET is connected with the output of control circuit through electric capacity, and the input of control circuit is connected with an end of the 3rd resistance; The other end of the 3rd resistance is connected with an end of the 5th resistance; The other end ground connection of the 5th resistance, the other end of the 3rd resistance also are connected with an end of the 4th resistance, and the other end of the 4th resistance is connected with the collector electrode of first triode.
When first triode transships, the collector electrode step-down of first triode, the second triode conducting, then first triode ends, the current collection of first triode low level very at this moment, the control circuit input end signal also is a low level.And if the first triode operate as normal, the current collection of first triode is high level very, then the control circuit input end signal also is a high level.Again open first triode when needs, the control circuit output is exported a high level, then FET conducting, and second triode ends, and first triode is resumed work.Therefore adopt this overload protecting circuit, the first triode automatic cut-off when overload takes place, the protection device is not damaged, and after recovery is normal, can sends signal again and make the triode of winning recover operate as normal.The advantage of the utility model is that circuit structure is simple, reliable in function, and circuit cost is lower.
Description of drawings
Fig. 1 is the circuit diagram of the utility model.
Embodiment
A kind of overload protecting circuit comprises the first triode Q1, and the emitter of this first triode Q1 connects power supply; Collector electrode connects load, and base stage is characterized in that through first resistance R, 21 ground connection the base stage of this first triode Q1 also is connected with the collector electrode of the second triode Q2; The emitter of this second triode Q2 connects power supply; The base stage of the second triode Q2 is connected with the collector electrode of the first triode Q1 through second resistance R 22, and the base stage of this second triode Q2 is connected with the source electrode of FET Q3, and the drain electrode of this FET Q3 connects power supply; The grid of this FET Q3 is connected with the output of control circuit (not shown) through electric capacity; The input of control circuit is connected with an end of the 3rd resistance R 29, and the other end of the 3rd resistance R 29 is connected with an end of the 5th resistance R 20, the other end ground connection of the 5th resistance R 20; The other end of the 3rd resistance R 29 also is connected with an end of the 4th resistance R 19, and the other end of the 4th resistance R 19 is connected with the collector electrode of the first triode Q1.
According to the preferred embodiment of the utility model, wherein the first triode Q1 adopts B772, and the second triode Q2 adopts 9012, and FET Q3 adopts Si2302.Wherein control circuit is a single-chip microcomputer.Load comprises current mode boost converter U1 (MP1542); The input IN of this current mode boost converter U1 is connected with the collector electrode of first triode; Be provided with inductance L 1 between the output SW of this current mode boost converter U1 and the input IN; And the output SW of this current mode boost converter U1 is connected with the positive pole of first diode, and the negative pole of first diode connects power output end, and the soft start control end SS of this current mode boost converter U1 is connected with the positive pole of the second diode D2; The negative pole of this second diode D2 is connected with the collector electrode of the first triode Q1; Also through large bulk capacitance C10 ground connection, according to the specific embodiment of the utility model, the capacity of this large bulk capacitance is 1uF to the soft start control end SS of this current mode boost converter U1.Adopt this large bulk capacitance can delay pneumatic process, place the influence of moment impact, thereby play the purpose of protection chip U1, further improve and adopt precision the first triode Q1.
Claims (5)
1. an overload protecting circuit comprises first triode, and the emitter of this first triode connects power supply; Collector electrode connects load, and base stage is characterized in that through first grounding through resistance base stage of this first triode also is connected with the collector electrode of second triode; The emitter of this second triode connects power supply; The base stage of second triode is connected with the collector electrode of first triode through second resistance, and the base stage of this second triode is connected with the source electrode of FET, and the drain electrode of this FET connects power supply; The grid of this FET is connected with the output of control circuit through electric capacity; The input of control circuit is connected with an end of the 3rd resistance, and the other end of the 3rd resistance is connected with an end of the 5th resistance, the other end ground connection of the 5th resistance; The other end of the 3rd resistance also is connected with an end of the 4th resistance, and the other end of the 4th resistance is connected with the collector electrode of first triode.
2. overload protecting circuit according to claim 1 is characterized in that: the first triode Q1 adopts B772, and the second triode Q2 adopts 9012, and FET Q3 adopts Si2302.
3. overload protecting circuit according to claim 1 is characterized in that: control circuit is a single-chip microcomputer.
4. overload protecting circuit according to claim 1; It is characterized in that: load comprises current mode boost converter; The input of this current mode boost converter is connected with the collector electrode of first triode; Be provided with inductance between the output of this current mode boost converter and the input; And the output of this current mode boost converter is connected with the positive pole of first diode, and the negative pole of first diode connects power output end, and the soft start control end of this current mode boost converter is connected with the positive pole of second diode; The negative pole of this second diode is connected with the collector electrode of first triode, and the soft start control end of this current mode boost converter is also through large bulk capacitance ground connection.
5. overload protecting circuit according to claim 4 is characterized in that: the current mode boost converter model is MP1542.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220201801 CN202586291U (en) | 2012-05-08 | 2012-05-08 | Overload protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220201801 CN202586291U (en) | 2012-05-08 | 2012-05-08 | Overload protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202586291U true CN202586291U (en) | 2012-12-05 |
Family
ID=47255659
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220201801 Expired - Lifetime CN202586291U (en) | 2012-05-08 | 2012-05-08 | Overload protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202586291U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105552825A (en) * | 2014-11-01 | 2016-05-04 | 江苏绿扬电子仪器集团有限公司 | Overload protection circuit system |
-
2012
- 2012-05-08 CN CN 201220201801 patent/CN202586291U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105552825A (en) * | 2014-11-01 | 2016-05-04 | 江苏绿扬电子仪器集团有限公司 | Overload protection circuit system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20121205 |
|
| CX01 | Expiry of patent term |