CN203554758U - Overvoltage-controlled LED constant current circuit - Google Patents
Overvoltage-controlled LED constant current circuit Download PDFInfo
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- CN203554758U CN203554758U CN201320674107.5U CN201320674107U CN203554758U CN 203554758 U CN203554758 U CN 203554758U CN 201320674107 U CN201320674107 U CN 201320674107U CN 203554758 U CN203554758 U CN 203554758U
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- 230000000087 stabilizing effect Effects 0.000 claims abstract description 11
- 239000003381 stabilizer Substances 0.000 claims description 25
- 239000004065 semiconductor Substances 0.000 claims description 21
- 239000003990 capacitor Substances 0.000 claims description 14
- 230000015572 biosynthetic process Effects 0.000 claims description 8
- 238000005755 formation reaction Methods 0.000 claims description 8
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
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Abstract
The utility model relates to an overvoltage-controlled LED constant current circuit. An RC filter circuit and a voltage stabilizing circuit are connected; a first current limiting branch and a second current limiting branch of a current limiting circuit are in serial connection; the first current limiting branch is connected with the voltage stabilizing circuit; the first current limiting branch and the second current limiting branch are respectively connected with a first LED serial connection branch and a second LED serial connection branch; an overvoltage circuit is connected with the RC filter circuit; the grid electrode of an MOS tube Q5 of the overvoltage circuit is connected onto the node of a resistor 22 and a resistor 23, and the source electrode is grounded; the base electrode of a triode Q1 of a constant current source driving circuit is connected with the drain electrode of the MOS tube Q5, the emitting electrode is grounded via a resistor R25, and the collector electrode is connected with the first LED serial connection branch; the base electrode of a triode Q2 is connected with the drain electrode of the MOS tube Q5, the emitting electrode is grounded via a resistor R27 and the collector electrode is connected with the second LED serial connection branch; and a voltage stabilizing tube D5 is connected between the base electrode of a triode Q1 and the resistor R25. According to the overvoltage-controlled LED constant current circuit, the circuit is simple, overvoltage protection can be carried out on an LED lamp group, and the luminescent efficiency and the service life of the LED lamp group are improved.
Description
Technical field
The utility model relates to the LED constant-current circuit that a kind of overvoltage is controlled, and belongs to car light technical field.
Background technology
LED is as light source, has that volume is little, lightweight, light source utilance is high, and power consumption is low, long service life, the exciter response time is short, and travel safety is good, and is conducive to the advantages such as vehicle appearance design, along with the fast development of automobile, the application of LED on car light is also more and more extensive.But LED, because the reasons such as its applied environment and supply power voltage electric current can cause damage, both may produce short circuit or breaking phenomena and damage, and can not meet light distribution requirements.In order to improve the stability of illumination, except updating the technique of LED, prevent outside its damage, the overvoltage of LED is controlled and protective circuit is also a focus of studying at present.
The arrangement mode of LED lamp for vehicles group adopts series parallel structure conventionally at present, and according to LED lamp group application scenario, conventionally adopts the mode of constant-current source to drive.When with triode driving LED circuit, when as long as the voltage in LED circuit surpasses certain value, the LED multi-path light source at its place can bear great voltage, can bring larger damage to multi-way LED lamp group like this, thereby affects luminous efficiency and the life cycle of LED lamp group.In the use procedure of car light, a paths of LEDs does not work or damages and tends to cause luminous intensity distribution not meet rules; And the overtension bearing as LED can cause the power of this paths of LEDs at its place excessive, thereby reduce the luminous efficiency of LED.Although at present a lot of LED car lights adopt overvoltage protection, circuit structure relative complex.
Summary of the invention
It is simple that the purpose of this utility model is to provide a kind of circuit, can play overvoltage protection effect to LED lamp group, improves the luminous efficiency of LED lamp group and the LED constant-current circuit that the overvoltage in useful life is controlled.
The utility model is that the technical scheme achieving the above object is: the LED constant-current circuit that a kind of overvoltage is controlled, it is characterized in that: comprise the RC filter circuit being connected with input power, voltage stabilizing circuit, current-limiting circuit and overvoltage crowbar and constant current source driving circuit, described voltage stabilizing circuit comprises resistance R 29, R24 and voltage-stabiliser tube D1, triode Q3 and capacitor C 5, the negative pole of voltage-stabiliser tube D1 connects RC filter circuit, anodal through resistance R 29 ground connection, the base stage of triode Q3 meets the positive pole of voltage-stabiliser tube D1 and the node place of resistance R 29, emitter is connected with the negative pole of voltage-stabiliser tube D1 through resistance R 24, collector electrode is through capacitor C 5 ground connection, described current-limiting circuit comprises the first current limliting branch road and the second current limliting branch road of serial connection, the first current limliting branch road is connected on the node place of voltage-stabiliser tube D1 and resistance R 24, the first current limliting branch road of at least three current-limiting resistance formations in parallel is connected with one end of a LED serial connection branch road, and the second branch of at least three current-limiting resistance formations in parallel presses road to be connected with one end of the 2nd LED serial connection branch road, described overvoltage circuit comprises resistance R 22, R23 and metal-oxide-semiconductor Q5, and resistance R 22 and R23 are connected between RC filter circuit and ground, the grid connecting resistance R22 of metal-oxide-semiconductor Q5 and node place, the source ground of R23, described constant current source driving circuit comprises voltage-stabiliser tube D5, triode Q1, Q2 and resistance R 25 and R27, drain electrode, emitter that the base stage of triode Q1 meets metal-oxide-semiconductor Q5 connect the other end of a LED serial connection branch road through resistance R 25 ground connection, collector electrode, drain electrode, emitter that the base stage of triode Q2 meets metal-oxide-semiconductor Q5 connect the other end of the 2nd LED serial connection branch road through resistance R 27 ground connection, collector electrode, voltage-stabiliser tube D5 is connected between the base stage and resistance R 25 ground of triode Q1.
The LED constant-current circuit that the utility model overvoltage is controlled adopts RC filter circuit, voltage stabilizing circuit, current-limiting circuit and overvoltage crowbar and constant current source driving circuit; by effective various interference and the noise in filtering LED constant-current circuit of RC filter circuit; make circuit overall performance keep stable; and play pressure stabilization function by voltage stabilizing circuit; the utility model reduces the power of LED lamp group by the current limliting branch road being connected on LED serial connection branch road, thereby has greatly improved luminous efficiency and the useful life of LED lamp group.Metal-oxide-semiconductor on the utility model overvoltage crowbar can be according to circuit input voltage; realize the adjusting of circuit voltage; when input voltage surpasses the starting resistor of metal-oxide-semiconductor, metal-oxide-semiconductor is opened and is lowered the voltage of LED constant-current circuit, can play overvoltage protection effect to LED lamp group.The utility model constant current source driving circuit adopts voltage-stabiliser tube D5 and triode Q1, Q2, make constant current source driving circuit not only there is the switching characteristic that triode is good, and be aided with the stabilized voltage characteristic that voltage-stabiliser tube is good, reduce in circuit because electric current is along with the variation of voltage there will be obvious variation.The utility model can be simplified circuit structure, and circuit is stable, can improve reliable operation, meets car light light distribution requirements.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further detail.
Fig. 1 is the electrical schematic diagram of the LED constant-current circuit of the utility model overvoltage control.
Fig. 2 is the block diagram of the LED constant-current circuit of the utility model overvoltage control.
Embodiment
See shown in Fig. 1,2, the LED constant-current circuit that overvoltage of the present utility model is controlled, comprises RC filter circuit, voltage stabilizing circuit, current-limiting circuit and the overvoltage crowbar and the constant current source driving circuit that are connected with input power,
RC filter circuit of the present utility model is π type RC filter circuit, RC filter circuit comprises capacitor C 1, C2, C3, C4 and resistance R 1 and diode D1, capacitor C 1, C2, resistance R 1 and capacitor C 3, C4 are successively and be connected between input power and ground, between diode D1 connecting resistance R1 and capacitor C 3, by RC filter circuit, can effectively filter various interference and the noise in LED constant current dividing circuit, make circuit overall performance keep stable.
As shown in Figure 1; voltage stabilizing circuit of the present utility model comprises resistance R 29, R24 and voltage-stabiliser tube D1, triode Q3 and capacitor C 5; the negative pole of voltage-stabiliser tube D1 connects RC filter circuit, anodal through resistance R 29 ground connection; the node place, emitter that the base stage of triode Q3 connects the positive pole of voltage-stabiliser tube D1 and resistance R 29 through resistance R 24 be connected with the negative pole of voltage-stabiliser tube D1, collector electrode is through capacitor C 5 ground connection; input voltage is after dividing potential drop; through triode Q3 and voltage-stabiliser tube D1, realize the automatic adjustment of output voltage, and maintain the stability of the utility model lamp group protective device output voltage.
As shown in Figure 1, current-limiting circuit of the present utility model comprises the first current limliting branch road and the second current limliting branch road of serial connection, the first current limliting branch road is connected on the node place of voltage-stabiliser tube D1 and resistance R 24, the first current limliting branch road of at least three current-limiting resistance formations in parallel is connected with one end of a LED serial connection branch road, the second branch of at least three current-limiting resistance formations in parallel presses road to be connected with one end of the 2nd LED serial connection branch road, the one LED serial connection branch road and the 2nd LED serial connection branch road bunchiness LED lighting circuit, the one LED serial connection branch road and the 2nd LED serial connection branch road form by a plurality of resistance and a plurality of light-emitting diode serial connection.As shown in Figure 1, a LED serial connection branch road of the present utility model comprises resistance R 19, diode (LED) 1, resistance R 13, diode (LED) 3 and the resistance R 15 of serial connection successively, the 2nd LED serial connection branch road comprises resistance R 14, diode (LED) 2, resistance R 20, diode (LED) 4 and the resistance R 21 of serial connection successively, makes a LED serial connection branch road be connected in series after branch road is connected and form connection in series-parallel lighting circuit with the 2nd LED.See showing of Fig. 1, the first current limliting of the present utility model is propped up route current-limiting resistance R2～R8 formation in parallel, same the second current limliting is propped up route current-limiting resistance R9～R12 and current-limiting resistance R16～R18 formation in parallel, by the first current limliting branch road and the second current limliting branch road, reduced the power of LED lamp group, thereby greatly improved LED lamp group luminous efficiency and useful life.
As shown in Figure 1, overvoltage circuit of the present utility model comprises resistance R 22, R23 and metal-oxide-semiconductor Q5, resistance R 22 and R23 are connected between RC filter circuit and ground, the grid connecting resistance R22 of metal-oxide-semiconductor Q5 and node place, the source ground of R23, the drain electrode of metal-oxide-semiconductor Q5 is connected with the base stage of triode Q and 1Q2, and to control the break-make of triode Q and 1Q2, the drain electrode of metal-oxide-semiconductor Q5 is also connected to resistance R 30,, and one end ground connection of resistance R 30.When input voltage does not reach overvoltage, can not make metal-oxide-semiconductor Q5 open, LED constant-current circuit of the present utility model is normally worked, and can realize constant current and drive, and makes each LED on LED serial connection branch road normally luminous; When input voltage is in overvoltage condition, as LED circuit voltage surpass 20V time be overvoltage, overvoltage value has reached the cut-in voltage of metal-oxide-semiconductor Q5, makes metal-oxide-semiconductor be opening, and the voltage of whole circuit is dragged down, thereby can reach the object of protection LED lamp group.
As shown in Figure 1, constant current source driving circuit of the present utility model comprises voltage-stabiliser tube D5, triode Q1, Q2 and resistance R 25 and R27, drain electrode, emitter that the base stage of triode Q1 meets metal-oxide-semiconductor Q5 connect the other end of a LED serial connection branch road through resistance R 25 ground connection, collector electrode, resistance R 26 is connected in parallel on the two ends of resistance R 25.The base stage of the utility model triode Q2 connects the drain electrode of metal-oxide-semiconductor Q5, emitter is through resistance R 27 ground connection, collector electrode connects the other end of the 2nd LED serial connection branch road, resistance R 28 is attempted by the two ends of resistance R 27, voltage-stabiliser tube D5 is connected between the base stage and resistance R 25 ground of triode Q1, by the good stabilized voltage characteristic of voltage-stabiliser tube D5, no matter how voltage changes to make electric current in whole circuit, there is good stability, the utility model drives respectively the break-make of a LED serial connection branch road and the 2nd LED serial connection branch road by triode Q1 and Q2, make LED normally light or not work, meet car light light distribution requirements.
Claims (5)
1. the LED constant-current circuit that an overvoltage is controlled, it is characterized in that: comprise RC filter circuit, voltage stabilizing circuit, current-limiting circuit and the overvoltage crowbar and the constant current source driving circuit that are connected with input power, described voltage stabilizing circuit comprises resistance R 29, R24 and voltage-stabiliser tube D1, triode Q3 and capacitor C 5, the negative pole of voltage-stabiliser tube D1 connects RC filter circuit, anodal through resistance R 29 ground connection, the node place, emitter that the base stage of triode Q3 connects the positive pole of voltage-stabiliser tube D1 and resistance R 29 through resistance R 24 be connected with the negative pole of voltage-stabiliser tube D1, collector electrode is through capacitor C 5 ground connection; Described current-limiting circuit comprises the first current limliting branch road and the second current limliting branch road of serial connection, the first current limliting branch road is connected on the node place of voltage-stabiliser tube D1 and resistance R 24, the first current limliting branch road of at least three current-limiting resistance formations in parallel is connected with one end of a LED serial connection branch road, and the second branch of at least three current-limiting resistance formations in parallel presses road to be connected with one end of the 2nd LED serial connection branch road; Described overvoltage circuit comprises resistance R 22, R23 and metal-oxide-semiconductor Q5, and resistance R 22 and R23 are connected between RC filter circuit and ground, the grid connecting resistance R22 of metal-oxide-semiconductor Q5 and node place, the source ground of R23; Described constant current source driving circuit comprises voltage-stabiliser tube D5, triode Q1, Q2 and resistance R 25 and R27, drain electrode, emitter that the base stage of triode Q1 meets metal-oxide-semiconductor Q5 connect the other end of a LED serial connection branch road through resistance R 25 ground connection, collector electrode, drain electrode, emitter that the base stage of triode Q2 meets metal-oxide-semiconductor Q5 connect the other end of the 2nd LED serial connection branch road through resistance R 27 ground connection, collector electrode, voltage-stabiliser tube D5 is connected between the base stage and resistance R 25 ground of triode Q1.
2. the LED constant-current circuit that overvoltage according to claim 1 is controlled, it is characterized in that: described RC filter circuit is π type RC filter circuit, described RC filter circuit comprises capacitor C 1, C2, C3, C4 and resistance R 1 and diode D1, capacitor C 1, C2, resistance R 1 and capacitor C 3, C4 successively and be connected between input power and ground, between diode D1 connecting resistance R1 and capacitor C 3.
3. the LED constant-current circuit that overvoltage according to claim 1 is controlled, is characterized in that: resistance R 26 is connected in parallel on the two ends of resistance R 25.
4. the LED constant-current circuit that overvoltage according to claim 1 is controlled, is characterized in that: resistance R 28 is connected in parallel on the two ends of resistance R 27.
5. the LED constant-current circuit that overvoltage according to claim 1 is controlled, is characterized in that: the drain electrode of described metal-oxide-semiconductor Q5 is also connected to resistance R 30 other end ground connection of resistance R 30.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320674107.5U CN203554758U (en) | 2013-10-29 | 2013-10-29 | Overvoltage-controlled LED constant current circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320674107.5U CN203554758U (en) | 2013-10-29 | 2013-10-29 | Overvoltage-controlled LED constant current circuit |
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| Publication Number | Publication Date |
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| CN203554758U true CN203554758U (en) | 2014-04-16 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201320674107.5U Expired - Lifetime CN203554758U (en) | 2013-10-29 | 2013-10-29 | Overvoltage-controlled LED constant current circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104582122A (en) * | 2013-10-29 | 2015-04-29 | 常州星宇车灯股份有限公司 | Overvoltage-controlled LED constant current circuit |
-
2013
- 2013-10-29 CN CN201320674107.5U patent/CN203554758U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104582122A (en) * | 2013-10-29 | 2015-04-29 | 常州星宇车灯股份有限公司 | Overvoltage-controlled LED constant current circuit |
| CN104582122B (en) * | 2013-10-29 | 2018-03-13 | 常州星宇车灯股份有限公司 | The LED constant current circuit of overvoltage control |
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| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140416 |