CN204145839U - A kind of constant current driver circuit for LED - Google Patents
A kind of constant current driver circuit for LED Download PDFInfo
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- CN204145839U CN204145839U CN201420570009.1U CN201420570009U CN204145839U CN 204145839 U CN204145839 U CN 204145839U CN 201420570009 U CN201420570009 U CN 201420570009U CN 204145839 U CN204145839 U CN 204145839U
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Abstract
The utility model discloses a kind of constant current driver circuit for LED, it comprises: 220v alternating current; Rectification filtering unit; Voltage sampling unit, it samples rear output for the direct voltage exported rectification filtering unit; Constant current driving unit, it is electrically connected to voltage sampling unit and LED string to be driven respectively, and the positive terminal of described LED string is electrically connected to the cathode output end of rectification filtering unit; Wherein, described constant current driving unit comprises constant current driving switch pipe Q2, and it adopts field effect transistor, and the G pole, control pole of described switching tube is electrically connected to described voltage sampling unit, drain electrode is connected to the negative pole of described LED string, and source electrode is connected to the cathode output end of described rectification filtering unit; Wherein, described constant current driving unit adjusts the conducting resistance of described switching tube based on the change of the input voltage of described voltage sampling unit collection and then realizes driving the constant current of LED string.Drive circuit described in the utility model Reliable guarantee LED can obtain constant electric current all the time.
Description
Technical field
The utility model belongs to LED control field, particularly relates to a kind of constant current driver circuit for LED.
Background technology
At present; because electrical network has a lot of variable; line voltage is made often to there will be fluctuation; and utilize line voltage as the LED drive circuit of input voltage; the fluctuation of line voltage will have influence on LED and occur the situations such as flicker; if fluctuation is comparatively large, LED can be damaged time serious, be therefore badly in need of the reliable voltage in the face of fluctuation of a kind of energy but LED flicker or the constant-current drive circuit of life-span length can not be had influence on.Although many many again of the existing drive circuit for LED, how in actual applications the fluctuation of ingenious reply input voltage keeps LED all the time by certain electric current, and allowing to be extended the useful life of LED is technical problem urgently to be resolved hurrily at present.
Utility model content
The utility model provides a kind of novel constant current driver circuit for LED based on the above-mentioned problem that will solve, when fluctuation appears in line voltage, this drive circuit can also ensure that LED obtains constant electric current, avoid and occur that the situation that LED is glimmered occurs, also improve the useful life of LED simultaneously.
The technical scheme that the utility model provides is:
A kind of constant current driver circuit for LED, it comprises:
220v alternating current, it provides power supply for described constant-current drive circuit;
Rectification filtering unit, it is electrically connected to described alternating current and carries out rectifying and wave-filtering to it and exports direct current;
Voltage sampling unit, it is electrically connected to described rectification filtering unit, and samples rear output to the direct voltage that described rectification filtering unit exports;
Constant current driving unit, it is electrically connected to described voltage sampling unit and LED string to be driven respectively, and the positive terminal of described LED string is electrically connected to the cathode output end of described rectification filtering unit; Wherein, described constant current driving unit comprises constant current driving switch pipe Q2, and it adopts field effect transistor, and the G pole, control pole of described switching tube is electrically connected to described voltage sampling unit, drain electrode is connected to the negative pole of described LED string, and source electrode is connected to the cathode output end of described rectification filtering unit; Wherein,
Described constant current driving unit adjusts the conducting resistance of described switching tube based on the change of the input voltage of described voltage sampling unit collection and then realizes driving the constant current of LED string.
Preferably, described rectification filtering unit adopts full-bridge rectification filter circuit, and its alternating current input two ends are connected to live wire and the zero line of civil power respectively; Wherein, the first filter capacitor C1 is connected with at the cathode output end of described rectification filtering unit.
Preferably, described voltage sampling unit comprises: the first resistance R1, the second resistance R2, the first voltage-stabiliser tube DZ1, triode Q1 and the 3rd resistance R3; Wherein,
First resistance R1 and the second resistance R2 is serially connected in cathode output end and the cathode output end of described rectification filtering unit; Described first voltage-stabiliser tube DZ1 negative pole is connected to the serial connection point of the first resistance R1 and the second resistance R2, and positive pole is connected to the base stage of described triode Q1; Described triode Q1 emitter connects the cathode output end of described rectification filtering unit, and collector electrode is connected to the cathode output end of described rectification filtering unit by the 3rd resistance R3, outputs to constant current driving unit simultaneously.
Preferably, described constant current driving unit also comprises: the 4th resistance R4, and it is connected between the collector electrode of described triode Q1 and the G pole, control pole of described switching tube Q2.
Preferably, described constant current driving unit also comprises: the second voltage-stabiliser tube DZ2, and its negative pole is connected to the collector electrode of described triode Q1, and positive pole is connected to the cathode output end of described rectification filtering unit.
Preferably, the positive terminal of described LED string is electrically connected to the cathode output end of described rectification filtering unit by a first diode D1, negative pole end is connected to the drain electrode of described switching tube by the 5th resistance R5.
Preferably, described constant current driver circuit for LED also comprises:
Second filter capacitor C2 and the 3rd filter capacitor C3, it is connected to the positive pole of described first diode D1 and the signal output part of described 5th resistance R5 respectively.
Preferably, described second filter capacitor adopts electrochemical capacitor.
Preferably, described LED string is forward connected in series by least plural LED and forms.
Constant current driver circuit for LED described in the utility model is by devising voltage sampling unit to gather line voltage at voltage input end, and the current value of LED string in real-time adjustment constant current driving unit is carried out according to the change of line voltage, make LED string under the line voltage of variation, brightness also can be kept constant, and do not glimmer.And wherein have employed the fast field effect transistor of switching speed as constant current driving switch pipe, it can adjust conducting resistance based on the size receiving control voltage in real time and then make LED string obtain constant electric current.This circuit design is simple, but helps greatly for having in useful life of LED, and it effectively prevents the line voltage of fluctuation on the impact of its normal work.
Accompanying drawing explanation
Fig. 1 is the circuit theory diagrams of constant current driver circuit for LED described in the utility model.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail, can implements according to this with reference to specification word to make those skilled in the art.
As shown in Figure 1, the utility model provides a kind of constant current driver circuit for LED, and it comprises: 220v alternating current, and it provides power supply for described constant-current drive circuit; Rectification filtering unit 1, it is electrically connected to described alternating current and carries out rectifying and wave-filtering to it and exports direct current; Voltage sampling unit 2, it is electrically connected to described rectification filtering unit, and samples rear output to the direct voltage that described rectification filtering unit exports; Constant current driving unit 3, it is electrically connected to described voltage sampling unit and LED string to be driven respectively, and the positive terminal of described LED string is electrically connected to the cathode output end of described rectification filtering unit; Wherein, described constant current driving unit comprises constant current driving switch pipe Q2, and it adopts field effect transistor, and the G pole, control pole of described switching tube is electrically connected to described voltage sampling unit, drain electrode is connected to the negative pole of described LED string, and source electrode is connected to the cathode output end of described rectification filtering unit; Wherein, described constant current driving unit adjusts the conducting resistance of described switching tube based on the change of the input voltage of described voltage sampling unit collection and then realizes driving the constant current of LED string.From Fig. 1, annexation can be seen, in the utility model, after the conducting change in resistance of switching tube Q2, the resistance in the conducting loop connecting LED string will be made to change, and then make the electric current of LED string remain on stationary value.
Here, from figure, described field effect transistor is the metal-oxide-semiconductor of N raceway groove.General metal-oxide-semiconductor is different from diode and triode, diode can only pass through forward current, reverse cut-off, can not control, and popular the saying of triode is exactly that small area analysis zooms into controlled big current, metal-oxide-semiconductor is then the size being carried out control output end drain current by the voltage being added in input grid, belongs to voltage-controlled type device.The utility model is exactly that ingenious this characteristic of metal-oxide-semiconductor that utilizes drives to the constant current realizing LED.Usual metal-oxide-semiconductor includes two types, a kind of is the metal-oxide-semiconductor of N raceway groove, another kind of then be P raceway groove, the two all has difference in a lot of characteristic and parameter, and the difference on state characteristic is: the metal-oxide-semiconductor of N raceway groove is greater than certain value at Vgs will conducting, be suitable for situation during source S ground connection, generally drive, as long as grid voltage reaches 4v or 10v as low side; And the metal-oxide-semiconductor of P raceway groove is less than the just meeting conducting of certain value at Vgs, be suitable for the situation that source electrode meets VCC, generally as high-side driver, but price, and replacement kind is few.Therefore the metal-oxide-semiconductor of N raceway groove is preferably adopted in the present invention, can be as seen from Figure 1.
Wherein, above-mentioned said rectification filtering unit 1 adopts full-bridge rectification filter circuit, and its alternating current input two ends (a, b point) is connected to live wire and the zero line of civil power respectively; Wherein, the first filter capacitor C1 is connected with at the cathode output end c of described rectification filtering unit.See Fig. 1, this belongs to the rectifier system that this area is comparatively commonly used, and is not therefore described in detail here.
Preferably, described voltage sampling unit 2 comprises: the first resistance R1, the second resistance R2, the first voltage-stabiliser tube DZ1, triode Q1 and the 3rd resistance R3; Wherein,
First resistance R1 and the second resistance R2 is serially connected in cathode output end c and the cathode output end d of described rectification filtering unit; Described first voltage-stabiliser tube DZ1 negative pole is connected to the serial connection point of the first resistance R1 and the second resistance R2, and positive pole is connected to the base stage of described triode Q1; Described triode Q1 emitter connects the cathode output end of described rectification filtering unit, and collector electrode is connected to the cathode output end of described rectification filtering unit by the 3rd resistance R3, outputs to constant current driving unit simultaneously.Described 3rd resistance R3 is the pull-up biasing resistor as triode Q1.When line voltage has fluctuation, the voltage of the serial connection point between the first resistance R1 and the second resistance R2 will change, this change will send into the base stage of triode Q1 through the first voltage-stabiliser tube DZ1, then by triode in its collector output generation change in voltage, thus be reacted to the constant current driving unit of rear class.
For voltage-stabiliser tube, itself and general-purpose diode are different, generally when using general-purpose diode, are just connecing positive electricity, negatively connect negative, and voltage-stabiliser tube negatively just connects, and just connecing negative, because be inherently operated in reverse breakdown district.The characteristic that voltage-stabiliser tube utilizes it reverse, after two ends add certain reverse voltage, diode meeting reverse-conducting, thus reach the effect of voltage stabilizing.More particularly, voltage stabilizing didoe is the device that the voltage regulation performance utilizing PN junction reverse breakdown characteristics to show is made.It is after utilizing diode to be reversed to puncture, and within the scope of certain reverse current, reverse voltage does not change this feature with reverse current and carries out voltage stabilizing.Voltage stabilizing didoe adopts alloyage or diffusion method to make by silicon semiconductor material usually.It had both had the unilateal conduction characteristic of general-purpose diode, can work in reverse breakdown state again.In the utility model, this first voltage-stabiliser tube DZ1 is just operated in reverse breakdown district.And when reverse voltage is lower, voltage stabilizing didoe ends; When reverse voltage reaches certain numerical value, reverse current increases suddenly, and voltage stabilizing didoe enters breakdown region, even if when now reverse current in very large range changes, the reverse voltage at voltage stabilizing didoe two ends also can keep substantially constant.If but after reverse current increases to certain numerical value, voltage stabilizing didoe then can be damaged by thoroughly puncturing.
Above-mentioned said constant current driving unit also comprises: the 4th resistance R4, and it is connected between the collector electrode of described triode Q1 and the G pole, control pole of described switching tube Q2.Connected from circuit, the 3rd resistance R3 in voltage sampling unit also constitutes the upper offset resistance of the switching tube Q2 in this constant current driving unit, described 3rd resistance R3 is connected to the G pole, control pole of switching tube Q2 after being connected in series with the 4th resistance, when the voltage that triode Q1 collector electrode exports changes, the control pole tension of this switching tube Q2 also ensues change, and then according to the characteristic of this switching tube as voltage-controlled device, the size of adjustable drain current, and drain current is just in time the electric current circulated in the conducting loop of LED string.
Preferably, described constant current driving unit also comprises: the second voltage-stabiliser tube DZ2, and its negative pole is connected to the collector electrode (being also the signal input part of the 4th resistance R4) of described triode Q1, and positive pole is connected to the cathode output end of described rectification filtering unit.Can see from circuit diagram, second voltage-stabiliser tube DZ2 is connected in parallel between the collector and emitter of triode Q1, form bleeder circuit with the 3rd resistance R3 simultaneously, can make on the one hand the trigger end G pole tension of switching tube Q2 can not be too high, form dividing potential drop with R3 on the other hand, determine dividing potential drop and then the control Q2 of R4 signal input part.
See Fig. 1, the positive terminal of the string of LED described in the utility model is electrically connected to the cathode output end of described rectification filtering unit by a first diode D1, negative pole end is connected to the drain electrode of described switching tube by the 5th resistance R5.Can understand like this, the conducting loop of described LED string is mains voltage output dc voltage after rectifying and wave-filtering, and this direct voltage flows back to rectification filtering unit again through the first diode D1, LED string, the 5th resistance R5 and switching tube Q3.Wherein, the 5th resistance R5 can be regarded as current-limiting resistance.The change of the conducting resistance between switching tube Q3 drain-source then can allow the electric current of LED string also can change.
Described constant current driver circuit for LED also comprises: the second filter capacitor C2 and the 3rd filter capacitor C3, and it is connected to the positive pole of described first diode D1 and the signal output part of described 5th resistance R5 respectively.Wherein said second filter capacitor adopts electrochemical capacitor.
As shown in Figure 1, described LED string is connected in series successively by least plural LED and forms.Namely the negative pole of first LED connects the positive pole of second LED, and the negative pole of second LED is connected in series the positive pole of the 3rd LED again, and forward serial connection forms LED string so successively, see the LED1-LEDn in Fig. 1.
The operation principle of constant current driver circuit for LED provided by the utility model is:
During Network Voltage Stability, the control pole G pole tension stable (through R3 and R4 gained) of switching tube Q3, the conducting resistance now between drain-source is also stabilized in a constant value, is in steady state with regard to making the electric current in LED string conducting loop;
When there is fluctuation in line voltage, the voltage of the serial connection point between the first resistance R1 and the second resistance R2 will change, this change sends into triode Q1 through the first voltage-stabiliser tube DZ1, then triode is at collector output generation curent change and then have adjusted the voltage be connected in series between the 3rd resistance R3 and the 4th resistance R4 a little, and this voltage will make the control pole G pole tension of switching tube Q3 change, the conducting resistance between drain-source now will be made to change, and then reach the electric current effect in stable LED string conducting loop.In other words, also can understand like this: when control pole (grid G) voltage of switching tube Q3 changes, will change at the drain current of output, line voltage change just in time can be offset the curent change that LED string produces by the change of this drain current, and then makes LED string be in constant current state all the time.
Although embodiment of the present utility model is open as above, but it is not restricted to listed in specification and execution mode utilization, it can be applied to various applicable field of the present utility model completely, for those skilled in the art, can easily realize other amendment, therefore do not deviating under the universal that claim and equivalency range limit, the utility model is not limited to specific details and illustrates here and the legend described.
Claims (9)
1. a constant current driver circuit for LED, is characterized in that, comprising:
220v alternating current, it provides power supply for described constant-current drive circuit;
Rectification filtering unit, it is electrically connected to described alternating current and carries out rectifying and wave-filtering to it and exports direct current;
Voltage sampling unit, it is electrically connected to described rectification filtering unit, and samples rear output to the direct voltage that described rectification filtering unit exports;
Constant current driving unit, it is electrically connected to described voltage sampling unit and LED string to be driven respectively, and the positive terminal of described LED string is electrically connected to the cathode output end of described rectification filtering unit; Wherein, described constant current driving unit comprises constant current driving switch pipe Q2, and it adopts field effect transistor, and the G pole, control pole of described switching tube is electrically connected to described voltage sampling unit, drain electrode is connected to the negative pole of described LED string, and source electrode is connected to the cathode output end of described rectification filtering unit; Wherein,
Described constant current driving unit adjusts the conducting resistance of described switching tube based on the change of the input voltage of described voltage sampling unit collection and then realizes driving the constant current of LED string.
2. constant current driver circuit for LED as claimed in claim 1, is characterized in that, described rectification filtering unit adopts full-bridge rectification filter circuit, and its alternating current input two ends are connected to live wire and the zero line of civil power respectively; Wherein, the first filter capacitor C1 is connected with at the cathode output end of described rectification filtering unit.
3. constant current driver circuit for LED as claimed in claim 2, it is characterized in that, described voltage sampling unit comprises: the first resistance R1, the second resistance R2, the first voltage-stabiliser tube DZ1, triode Q1 and the 3rd resistance R3; Wherein,
First resistance R1 and the second resistance R2 is serially connected in cathode output end and the cathode output end of described rectification filtering unit; Described first voltage-stabiliser tube DZ1 negative pole is connected to the serial connection point of the first resistance R1 and the second resistance R2, and positive pole is connected to the base stage of described triode Q1; Described triode Q1 emitter connects the cathode output end of described rectification filtering unit, and collector electrode is connected to the cathode output end of described rectification filtering unit by the 3rd resistance R3, outputs to constant current driving unit simultaneously.
4. constant current driver circuit for LED as claimed in claim 3, it is characterized in that, described constant current driving unit also comprises: the 4th resistance R4, and it is connected between the collector electrode of described triode Q1 and the G pole, control pole of described switching tube Q2.
5. constant current driver circuit for LED as claimed in claim 3, it is characterized in that, described constant current driving unit also comprises: the second voltage-stabiliser tube DZ2, and its negative pole is connected to the collector electrode of described triode Q1, and positive pole is connected to the cathode output end of described rectification filtering unit.
6. constant current driver circuit for LED as claimed in claim 5, it is characterized in that, the positive terminal of described LED string is electrically connected to the cathode output end of described rectification filtering unit by a first diode D1, negative pole end is connected to the drain electrode of described switching tube by the 5th resistance R5.
7. constant current driver circuit for LED as claimed in claim 6, is characterized in that, also comprise:
Second filter capacitor C2 and the 3rd filter capacitor C3, it is connected to the positive pole of described first diode D1 and the signal output part of described 5th resistance R5 respectively.
8. constant current driver circuit for LED as claimed in claim 7, is characterized in that, described second filter capacitor adopts electrochemical capacitor.
9. constant current driver circuit for LED as claimed in claim 8, it is characterized in that, described LED string is forward connected in series by least plural LED and forms.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420570009.1U CN204145839U (en) | 2014-09-29 | 2014-09-29 | A kind of constant current driver circuit for LED |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420570009.1U CN204145839U (en) | 2014-09-29 | 2014-09-29 | A kind of constant current driver circuit for LED |
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| CN204145839U true CN204145839U (en) | 2015-02-04 |
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| CN201420570009.1U Expired - Fee Related CN204145839U (en) | 2014-09-29 | 2014-09-29 | A kind of constant current driver circuit for LED |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106992501A (en) * | 2017-04-19 | 2017-07-28 | 赛尔富电子有限公司 | The dc source and its LED lamp and control system of a kind of anti-output false power supply |
| CN107580390A (en) * | 2017-09-18 | 2018-01-12 | 佛山市国星光电股份有限公司 | A kind of LED lamp |
| CN107920406A (en) * | 2017-12-07 | 2018-04-17 | 厦门恩耐照明技术有限公司 | A kind of open loop protection circuit in self-maintained circuit |
| CN108063437A (en) * | 2017-12-28 | 2018-05-22 | 广州爱易学智能信息科技有限公司 | The short-circuit protection circuit of classroom blackboard LED light strip |
| CN108809127A (en) * | 2018-07-19 | 2018-11-13 | 帝森克罗德集团有限公司 | Wide input voltage regulator rectifier circuit |
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2014
- 2014-09-29 CN CN201420570009.1U patent/CN204145839U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106992501A (en) * | 2017-04-19 | 2017-07-28 | 赛尔富电子有限公司 | The dc source and its LED lamp and control system of a kind of anti-output false power supply |
| CN107580390A (en) * | 2017-09-18 | 2018-01-12 | 佛山市国星光电股份有限公司 | A kind of LED lamp |
| CN107580390B (en) * | 2017-09-18 | 2023-12-19 | 佛山市国星光电股份有限公司 | LED lamp |
| CN107920406A (en) * | 2017-12-07 | 2018-04-17 | 厦门恩耐照明技术有限公司 | A kind of open loop protection circuit in self-maintained circuit |
| CN108063437A (en) * | 2017-12-28 | 2018-05-22 | 广州爱易学智能信息科技有限公司 | The short-circuit protection circuit of classroom blackboard LED light strip |
| CN108809127A (en) * | 2018-07-19 | 2018-11-13 | 帝森克罗德集团有限公司 | Wide input voltage regulator rectifier circuit |
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