CN202334995U - Light-emitting diode (LED) constant-current control circuit controlled by transistors - Google Patents

Light-emitting diode (LED) constant-current control circuit controlled by transistors Download PDF

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Publication number
CN202334995U
CN202334995U CN2011203939761U CN201120393976U CN202334995U CN 202334995 U CN202334995 U CN 202334995U CN 2011203939761 U CN2011203939761 U CN 2011203939761U CN 201120393976 U CN201120393976 U CN 201120393976U CN 202334995 U CN202334995 U CN 202334995U
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China
Prior art keywords
circuit
triode
line
led
resistance
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Expired - Fee Related
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CN2011203939761U
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Chinese (zh)
Inventor
孟光毅
郑阮元
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孟光毅
郑阮元
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Priority to CN2011203939761U priority Critical patent/CN202334995U/en
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Anticipated expiration legal-status Critical
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Abstract

The utility model relates to a light-emitting diode (LED) constant-current control circuit transistors controlling controlled by transistors, which comprises a Buck circuit connected with a line, the Buck circuit is connected with a resistance R11 which is connected with emitters of a NPN shaped transistor Q2 and a PNP shaped transistor Q3 through the line respectively, a collector of the transistor Q2 is connected with a +12V power source through the line, a base of the transistor Q2 is connected with a collector of a NPN shaped transistor Q4 and a resistance R12, the collector of the transistor Q4 is connected with a base of transistor Q3 through the line, the base of transistor Q4 is connected with a diode D15 and a resistance R13 through the line, an output terminal of the resistance R13 is connected with an input terminal of transformer T1 through the line, and the output terminal of transformer T1 is connected with an output line of the Buck circuit. The light-emitting diode (LED) constant-current control circuit is constituted by transistors and has a stable power output, a current critical conduction mode can be excellently guaranteed by zero-current detecting control of the control circuit and the light-emitting diode (LED) constant-current control circuit has constant-current function.

Description

A kind of LED constant-current control circuit by triode control
Technical field
The utility model relates to a kind of LED constant-current control circuit by triode control.
Background technology
Electric consumption on lighting occupies the total electricity consumption in the whole world 21% at present, if can improve the efficient of illumination, can effectively alleviate energy shortage.How to improve the energy utilization rate of illuminator, prolong the life-span of illuminator, and be green non-pollution? Replace incandescent lamp, fluorescent lamp, electricity-saving lamp the 4th generation lighting what is? The answer that industry provides is exactly the illumination of LED lamp.LED every W that throws light on can reach 120lm, and far above incandescent lamp and fluorescent lamp, the LED lamp pearl life-span is 100,000 hours in addition, and green non-pollution.These advantages that the LED illumination possesses have determined that its application prospect is very wide.LED illumination application limit is that LED has fixing forward voltage drop, and electric current also has the upper limit (operating current is the principal element that influences the LED life-span).Forward voltage drop on the large power white light LED is generally 3V-4V, can not directly use civil power to drive.Therefore need one with efficient, the environmental protection of LED lamp pearl coupling, long-life power supply, LED illumination driving switch power supply project construction meaning that Here it is.
Development along with domestic LED industry; The national policy aspect day by day strengthens the concern of LED industry; Under the drive of country's " energy-saving and emission-reduction " policy, the capital construction project goes into operation in succession, and market is to the approval gradually of LED product; The illumination market share will be increasing at home to believe LED enterprise, and LED industrial market prospect is with boundless.
The LED illumination driving circuit should have functions such as constant current output, no-load protection, isolation output and EMC.System is applied to LED illumination switch driven power circuit.Adopt PWM to regulate automatically and realize constant current output, the voltage-stabiliser tube over-voltage locking is realized no-load protection, and electromagnetic isolation and light isolation realize isolating output, but present LED illumination driving circuit complex structure, the cost height, current loss is big.
The utility model content
For solving the problems of the technologies described above, the utility model provides a kind of LED constant-current control circuit simple in structure, easy to use, that controlled by triode efficiently.
The LED constant-current control circuit by triode control of the utility model; Comprise connection Buck circuit in the line; Connect resistance R 11 on the Buck circuit, resistance R 11 connects the emitter of NPN shape triode Q2 and PNP shape triode Q3 respectively through circuit, and the collector electrode of triode Q3 is through line-to-ground; The collector electrode of triode Q2 is through circuit connection+12V power supply; The base stage of triode Q2 connects collector electrode and the resistance R 12 of NPN shape triode Q4 respectively through circuit, and resistance R 12 is connected with the collector electrode of triode Q2 through circuit, and the collector electrode of triode Q4 passes through circuit and is connected with the base stage of triode Q3; The emitter of triode Q4 is through line-to-ground; The base stage of triode Q4 connects diode D15 and resistance R 13 respectively through circuit, and the other end of diode D15 is through line-to-ground, and the output of resistance R 13 connects the input of transformer T1 through circuit; Transformer T1 output is connected on the outlet line of Buck circuit, is provided with current sampling circuit between the left side output of transformer T1 and the Buck circuit.
The LED constant-current control circuit by triode control of the utility model, incoming line of said Buck circuit and another input of transformer T1 are all through line-to-ground.
The LED constant-current control circuit by triode control of the utility model, said current sampling circuit is connected with the base stage of triode Q4 through circuit.
Compared with prior art the beneficial effect of the utility model is: the LED driving power of the utility model adopts the control circuit of being made up of triode, and circuit is simple and power output is stable, has lower cost simultaneously.The zero current detection control of control circuit can be good at guaranteeing the electric current critical conduction mode, has the constant current function.
Description of drawings
Fig. 1 is the schematic block circuit diagram of the described LED constant-current control circuit by triode control of the utility model embodiment.
Among the figure:
1, Buck circuit; 2, current sampling circuit.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the embodiment of the utility model is described in further detail.Following examples are used to explain the utility model, but are not used for limiting the scope of the utility model.
As shown in Figure 1; A kind of LED constant-current control circuit by triode control comprises connection Buck circuit 1 in the line, connects resistance R 11 on the Buck circuit 1; Resistance R 11 connects the emitter of NPN shape triode Q2 and PNP shape triode Q3 respectively through circuit; The collector electrode of triode Q3 is through line-to-ground, and the collector electrode of triode Q2 is through circuit connection+12V power supply, and the base stage of triode Q2 connects collector electrode and the resistance R 12 of NPN shape triode Q4 respectively through circuit; Resistance R 12 is connected with the collector electrode of triode Q2 through circuit; The collector electrode of triode Q4 is connected with the base stage of triode Q3 through circuit, and the emitter of triode Q4 is through line-to-ground, and the base stage of triode Q4 connects diode D15 and resistance R 13 respectively through circuit; The other end of diode D15 is through line-to-ground; The output of resistance R 13 is through the input of circuit connection transformer T1, and transformer T1 output is connected on the outlet line of Buck circuit 1, is provided with current sampling circuit 2 between the left side output of transformer T1 and the Buck circuit 1.
The LED constant-current control circuit by triode control of the utility model, incoming line of said Buck circuit 1 and another input of transformer T1 are all through line-to-ground.
The LED constant-current control circuit by triode control of the utility model, said current sampling circuit 2 is connected with the base stage of triode Q4 through circuit.
The LED constant-current control circuit by triode control of the utility model, the left side output of said transformer T1 is connected with the base stage of triode Q4 through circuit, and it (is that base voltage is greater than 0.7V that driving triode Q4 utilizes its inherent characteristic; The collector and emitter conducting of triode; Base voltage is less than 0.7V, and collector and emitter breaks off), can be according to detected electric current and zero current signal; Turn on and off; When the current signal (current signal converts voltage signal to through inductive current sample circuit 2) that detects when reaching 0.7V, Q4 conducting, the drive signal of Buck circuit 1 is low; Inductive current in the Buck circuit 1 reduces, and the induced voltage that the secondary through transformer T1 (side that links with Q4) obtains is kept the Q4 conducting; When inductive current was reduced to 0, the induced voltage of the secondary of T1 also became 0, and this moment, Q4 turn-offed; The drive signal of Buck circuit 1 is high; Inductive current in the Buck circuit 1 begins to increase at this moment, and when the voltage signal of inductive current sample circuit 2 reached 0.7V, Q4 turn-offed; So move in circles, make Buck circuit 1 be operated in the critical flow Discontinuous Conduction mode.
The above only is the preferred implementation of the utility model; Should be understood that; For those skilled in the art; Under the prerequisite that does not break away from the utility model know-why, can also make some improvement and modification, these improvement and modification also should be regarded as the protection range of the utility model.

Claims (3)

1. LED constant-current control circuit by triode control; Comprise connection Buck circuit (1) in the line; It is characterized in that: said Buck circuit (1) go up to connect resistance R 11, and resistance R 11 connects the emitter of NPN shape triode Q2 and PNP shape triode Q3 respectively through circuit, and the collector electrode of triode Q3 is through line-to-ground; The collector electrode of triode Q2 is through circuit connection+12V power supply; The base stage of triode Q2 connects collector electrode and the resistance R 12 of NPN shape triode Q4 respectively through circuit, and resistance R 12 is connected with the collector electrode of triode Q2 through circuit, and the collector electrode of triode Q4 passes through circuit and is connected with the base stage of triode Q3; The emitter of triode Q4 is through line-to-ground; The base stage of triode Q4 connects diode D15 and resistance R 13 respectively through circuit, and the other end of diode D15 is through line-to-ground, and the output of resistance R 13 connects the input of transformer T1 through circuit; Transformer T1 output is connected on the outlet line of Buck circuit (1), is provided with current sampling circuit (2) between the left side output of transformer T1 and the Buck circuit (1).
2. the LED constant-current control circuit by triode control according to claim 1 is characterized in that: incoming line of said Buck circuit (1) and another input of transformer T1 are all through line-to-ground.
3. the LED constant-current control circuit by triode control according to claim 1 and 2 is characterized in that: said current sampling circuit (2) is connected with the base stage of triode Q4 through circuit.
CN2011203939761U 2011-10-11 2011-10-11 Light-emitting diode (LED) constant-current control circuit controlled by transistors Expired - Fee Related CN202334995U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2011203939761U CN202334995U (en) 2011-10-11 2011-10-11 Light-emitting diode (LED) constant-current control circuit controlled by transistors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN2011203939761U CN202334995U (en) 2011-10-11 2011-10-11 Light-emitting diode (LED) constant-current control circuit controlled by transistors

Publications (1)

Publication Number Publication Date
CN202334995U true CN202334995U (en) 2012-07-11

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Country Status (1)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103052204A (en) * 2011-10-11 2013-04-17 孟光毅 Light emitting diode (LED) constant-current control circuit controlled by triodes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103052204A (en) * 2011-10-11 2013-04-17 孟光毅 Light emitting diode (LED) constant-current control circuit controlled by triodes

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C14 Grant of patent or utility model
GR01 Patent grant
EXPY Termination of patent right or utility model
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20120711

Termination date: 20141011