CN202634850U - Light-emitting diode (LED) constant current driving system - Google Patents
Light-emitting diode (LED) constant current driving system Download PDFInfo
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- CN202634850U CN202634850U CN 201220316401 CN201220316401U CN202634850U CN 202634850 U CN202634850 U CN 202634850U CN 201220316401 CN201220316401 CN 201220316401 CN 201220316401 U CN201220316401 U CN 201220316401U CN 202634850 U CN202634850 U CN 202634850U
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- comparator
- led
- triode
- resistance
- current driving
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Abstract
The utility model discloses a light-emitting diode (LED) constant current driving system, which comprises a first comparator, a second comparator, a first resistor, a first triode and an LED, wherein one end of the first resistor is connected to an inverse phase input end of the first comparator, and the other end of the first resistor is connected with a circuit between an output end of the first comparator and an in-phase input end of the second comparator; an output end of the second comparator is connected with a base of the first triode; an inverse phase input end of the second comparator is connected with an emitter of the first triode; a direct current voltage input line and a trigger voltage input line are connected to the first comparator; an output end of the LED is connected with a collector of the first triode; and an input end of the LED is connected to the direct current voltage input line. The LED constant current driving system is simple in structure, small in size and low in cost, and fewer components are used; and moreover, when the LED constant current driving system is used, current acting on the LED is constant, the LED is difficult to damage, and the testing reliability is high.
Description
Technical field
The utility model relates to a kind of drive circuit, specifically is LED constant-current driving system.
Background technology
LED has little, the low cost and other advantages of volume, so people usually are used for LED the input of some systems, and when system testing, whether lights to judge through the LED lamp whether signal is connected in the system.As a semiconductor device that is operated in low-voltage, direct current, LED needs work under constant electric current environment.Mains-supplied commonly used during general system power supply if need LED luminous when detecting in system, then needs to carry out rectification control back through drive circuit to alternating voltage and supplies the LED use.Electrology characteristic by LED can be known; The mean forward current of LED is along with the increase of forward voltage presents significantly linear growth; The change of LED its forward voltage behind forward conduction will cause the LED very big variation of stream that powers on; And electric current is very big to the influence of LED junction temperature, and excessive electric current is easy to cause LED to damage because of junction temperature raises.Damage and the accuracy of influence test defective such as there is complex structure in existing LED constant-current drive circuit, components and parts are many, cost is high and reliability is low for fear of LED.
The utility model content
The purpose of the utility model is to overcome the deficiency of prior art, provide a kind of simple in structure, cost is low, when using, can avoid damaging, and then improve the LED constant-current driving system of system testing reliability because of variation in voltage causes light-emitting diode.
The purpose of the utility model mainly realizes through following technical scheme: LED constant-current driving system; Comprise first comparator, second comparator, first resistance, first triode and light-emitting diode; The output of said first comparator is connected with the in-phase input end of second comparator; Said first resistance, one end is connected on the inverting input of first comparator; Its other end is connected with circuit between first comparator output terminal and the second comparator in-phase input end, and the output of said second comparator is connected with the base stage of first triode, and the inverting input of second comparator is connected with first transistor emitter; Connect the direct voltage incoming line on first comparator; Be connected with the trigger voltage incoming line on the first comparator in-phase input end, the output of said light-emitting diode is connected with the collector electrode of first triode, and the light-emitting diode input is connected on the direct voltage incoming line.The direct voltage incoming line specifically is connected on the forward voltage input of first comparator, the utility model when using, direct voltage incoming line external direct current power supply, the system's supply power voltage after the external rectification conversion of trigger voltage incoming line.
LED constant-current driving system also comprises second resistance and the 3rd resistance, and said second resistance, one end is connected on the circuit between the first comparator inverting input and first resistance its other end ground connection; Said second resistance, one end connects on the circuit between the second comparator inverting input and first transistor emitter its other end ground connection.
Said first resistance is adjustable resistance.
Said first triode is a NPN type triode.
Compared with prior art, the utlity model has following beneficial effect: the utility model comprises first comparator, second comparator, first resistance, first triode and light-emitting diode, and overall structure is simple; Be convenient to realize that used components and parts are few, cost is low; Wherein, connect the direct voltage incoming line on first comparator, be connected with the trigger voltage incoming line on the first comparator in-phase input end; When the utility model is used for system testing; Voltage through treating examining system is as the trigger voltage of the utility model, and the direct voltage of importing on the direct voltage incoming line makes the supply power voltage of lumination of light emitting diode stable just as the supply power voltage of light-emitting diode; Thereby can not damage, improve the reliability when the utility model is used because of variation in voltage on the light-emitting diode causes light-emitting diode.
Description of drawings
Fig. 1 is the structural representation of the utility model embodiment.
The pairing name of Reference numeral is called in the accompanying drawing: A1-first comparator, A2-second comparator, R1-first resistance; R2-second resistance, R3-the 3rd resistance, Q1-first triode; LED1-light-emitting diode, 1-trigger voltage incoming line, 2-direct voltage incoming line.
Embodiment
Below in conjunction with embodiment and accompanying drawing the utility model is done further to specify, but the execution mode of the utility model is not limited thereto.
Embodiment:
As shown in Figure 1; LED constant-current driving system; Comprise shell and internal circuit in the enclosure be set that wherein, internal circuit comprises the first comparator A1, the second comparator A2, first resistance R 1, second resistance R 2, the 3rd resistance R 3, the first triode Q1 and LED 1; First resistance R 1 is an adjustable resistance, and the first triode Q1 is a NPN type triode.The output of the first comparator A1 is connected with the in-phase input end of the second comparator A2; First resistance R, 1 one ends are connected on the inverting input of the first comparator A1, and its other end is connected with circuit between the first comparator A1 output and the second comparator A2 in-phase input end.The output of the second comparator A2 is connected with the base stage of the first triode Q1; The inverting input of the second comparator A2 is connected with the first triode Q1 emitter; The first comparator A1 goes up and connects the direct voltage incoming line 2 that is used for external direct current power supply; Be connected with trigger voltage incoming line 1 on the first comparator A1 in-phase input end, trigger voltage incoming line 1 is used to receive the voltage input after the system to be tested rectification.The output of LED 1 is connected with the collector electrode of the first triode Q1, and LED 1 input is connected on the direct voltage incoming line 2.As preferably, the first comparator A1 and the second comparator A2 all adopt LM358 in the present embodiment.
Second resistance R, 2 one ends are connected on the circuit between the first comparator A1 inverting input and first resistance R 1, and it connects the other end ground connection of the line scan pickup coil side between the first comparator A1 inverting input and first resistance R 1 relatively.Second resistance R, 2 one ends connect on the circuit between the second comparator A2 inverting input and the first triode Q1 emitter, and it connects the other end ground connection of the line scan pickup coil side between the second comparator A2 inverting input and the first triode Q1 emitter relatively.
As stated, then can well realize the utility model.
Claims (4)
1.LED constant-current driving system; It is characterized in that: comprise first comparator (A1), second comparator (A2), first resistance (R1), first triode (Q1) and light-emitting diode (LED1); The output of said first comparator (A1) is connected with the in-phase input end of second comparator (A2); Said first resistance (R1) end is connected on the inverting input of first comparator (A1); Its other end is connected with circuit between first comparator (A1) output and second comparator (A2) in-phase input end; The output of said second comparator (A2) is connected with the base stage of first triode (Q1); The inverting input of second comparator (A2) is connected with first triode (Q1) emitter, and first comparator (A1) is gone up and connected direct voltage incoming line (2), is connected with trigger voltage incoming line (1) on first comparator (A1) in-phase input end; The output of said light-emitting diode (LED1) is connected with the collector electrode of first triode (Q1), and light-emitting diode (LED1) input is connected on the direct voltage incoming line (2).
2. LED constant-current driving according to claim 1 system; It is characterized in that: also comprise second resistance (R2) and the 3rd resistance (R3); Said second resistance (R2) end is connected on the circuit between first comparator (A1) inverting input and first resistance (R1), its other end ground connection; Said second resistance (R2) end connects on the circuit between second comparator (A2) inverting input and first triode (Q1) emitter, its other end ground connection.
3. LED constant-current driving according to claim 1 system, it is characterized in that: said first resistance (R1) is adjustable resistance.
4. according to described any LED constant-current driving system of claim 1～3, it is characterized in that: said first triode (Q1) is a NPN type triode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220316401 CN202634850U (en) | 2012-07-03 | 2012-07-03 | Light-emitting diode (LED) constant current driving system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220316401 CN202634850U (en) | 2012-07-03 | 2012-07-03 | Light-emitting diode (LED) constant current driving system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202634850U true CN202634850U (en) | 2012-12-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220316401 Expired - Fee Related CN202634850U (en) | 2012-07-03 | 2012-07-03 | Light-emitting diode (LED) constant current driving system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202634850U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103533695A (en) * | 2012-07-03 | 2014-01-22 | 成都市宏山科技有限公司 | LED constant-current driving system |
-
2012
- 2012-07-03 CN CN 201220316401 patent/CN202634850U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103533695A (en) * | 2012-07-03 | 2014-01-22 | 成都市宏山科技有限公司 | LED constant-current driving system |
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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: 20121226 Termination date: 20130703 |