CN205082029U - Weak current switch formula LED constant -current drive circuit - Google Patents
Weak current switch formula LED constant -current drive circuit Download PDFInfo
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- CN205082029U CN205082029U CN201520891962.0U CN201520891962U CN205082029U CN 205082029 U CN205082029 U CN 205082029U CN 201520891962 U CN201520891962 U CN 201520891962U CN 205082029 U CN205082029 U CN 205082029U
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Abstract
The utility model discloses a weak current switch formula LED constant -current drive circuit, it comprises current -limiting device, feedback device, constant current switch and controller. Wherein mains voltage passes through the current -limiting device insert LED, LED is connected again to the constant current switch, and passes through feedback device ground connection, the controller is connected the constant current switch and is failed entry control voltage with control the above -mentioned LED of constant current switch drive. The utility model discloses the circuit can conveniently adopt the weak current signal to come opening and closing of control circuit, uses the on -off control signal of constant current switching mode output than the weak current to control switching on and turn -offing of LED jointly with power supply.
Description
Technical field
The utility model relates to light-emitting diode (LED) Driving technique, particularly relates to a kind of constant current driver circuit for LED realizing weak-current switch control of low cost.
Background technology
Along with the development of LED technology, LED is more and more extensive in the application of lighting field.LED, as the light source of electric lighting, owing to needing constant current when LED works, therefore needs special drive circuit.The circuit design of non-constant current drive form is more simple, but drive current is difficult to be consistent, and need the metastable power supply of voltage to carry out driving LED and irradiate, brightness is also difficult to accomplish that brightness is consistent.And constant-current drive circuit is complicated, constant current can be realized and drive, but circuit cost is higher.If LED number is more in a light fixture, then need the drive circuit of multiple-channel output.At present, multiple-channel output LED drive circuit, usually adopt MCU to add current constant control chip solution, Multi-path LED load needs the current constant control chip of respective numbers, and cost compare is high.And current constant current driver circuit for LED is not undertaken opening and turning off by weak current signal.
Utility model content
The utility model adopts the very simple constant-current drive circuit of a kind of structure to drive: LED component, to ensure its brightness of illumination consistency, and, the utility model circuit can adopt weak current signal to carry out the opening and closing of control circuit easily, use constant current switch mode to export switch controlling signal compared with weak current, and with the turn-on and turn-off of power supply co-controlling LED.
For solving the problem, the utility model have employed following technical scheme:
Technical scheme 1: a kind of weak-current switch formula constant current driver circuit for LED, it is made up of current limiting device, feedback device, constant current switch and controller.Wherein supply voltage is by described current limiting device access LED, and described constant current switch connects LED again, and by described feedback device ground connection, described controller connects constant current switch and input control voltage drives above-mentioned LED to control described constant current switch.
As improvement, described constant current switch is NPN type triode Q, and the LED described in its base stage connection control device, collector electrode connect, emitter-base bandgap grading connect feedback device.
As another improvement, described current limiting device is current-limiting resistance R2, and one termination enters described supply voltage, and the other end accesses described LED; Described feedback device is feedback resistance R1, and one termination enters described NPN type triode Q, other end ground connection.In effect of the present utility model, use current-limiting resistance R2 can suppress the characteristic voltage V of NPN type triode Q
cE, thus reduce NPN type triode Q power consumption.
Technical scheme 2: a kind of weak-current switch formula constant current driver circuit for LED, it is made up of feedback device, constant current switch and controller, wherein supply voltage access LED, described constant current switch connects LED, and by described feedback device ground connection, described controller connects constant current switch and input control voltage drives above-mentioned LED to control described constant current switch.
As improvement, described constant current switch is NPN type triode Q, and the LED described in its base stage connection control device, collector electrode connect, emitter-base bandgap grading connect feedback device.
Constant current driver circuit for LED structure of the present utility model is simple, can stablize LED operating current in constant current switch mode, and uses the conducting compared with weak current signal control LED and closedown, simple and practical.
Accompanying drawing explanation
Fig. 1 schematically shows circuit of the present utility model local schematic diagram.
Embodiment
Embodiment 1: for illuminating device
LED component is widely used in lighting technology, and as display backlight, indicator light or other illumination components and parts etc. in electronic product, LED luminance is mainly decided by the size of current flow through wherein.The weak-current switch formula constant current driver circuit for LED of the present embodiment, it is made up of current limiting device, feedback device, constant current switch and controller 1, wherein supply voltage is by described current limiting device access LED, described constant current switch connects LED again, and by described feedback device ground connection GND, described controller connects constant current switch and input control voltage drives above-mentioned LED to control described constant current switch.
With reference to Fig. 1, described constant current switch is NPN type triode Q, and LED, emitter-base bandgap grading E described in its base stage B connection control device 1, collector electrode C connect connect feedback device.Described current limiting device is current-limiting resistance R2, and one termination enters supply voltage, and the other end accesses described LED; Described feedback device is feedback resistance R1, and one termination enters described NPN type triode Q, other end ground connection.
In the present embodiment, the electric current flowing through light-emitting diode (LED) approximates:
I
LED≈(V
OUT—V
BE)/R
1，
Consider the output voltage V of controller 1 control end
oUTwith triode forward voltage drop V
fall can be more stable, the electric current therefore flowing through this LED will be more stable.As shown in Figure 1, the control end of described controller 1 can be used as reference voltage source, and described constant current switch is connected in the current supply circuit of described LED.Due to reference voltage source V
oUTfor constant current switch provides stable reference voltage, and the electric current of constant current switch for stablizing in the current supply circuit of LED, when there is fluctuation in the DC DC power supply accessed in LED current supply circuit, the constant current switch electric current can stablized in LED current supply circuit makes the current stabilization by illustrating LED, avoids LED flicker, light and shade non-uniform phenomenon.
Constant current switch Q receives the control signal V of constant-current source
oUTcontrol opening and closing to control NPN triode Q and reference voltage source VCC conducting or disconnection, when the Q conducting of NPN triode, reference voltage source V
oUTfor the base stage B of NPN triode Q provides high level to input, form base current, emitter E forms emitter current and flows through ground connection after feedback resistance R1, and the power supply in the current supply circuit of LED is external dc power VCC (such as, cell voltage or direct current power source voltage).
Due to the positive termination VCC of LED, cause the electric current flowing through LED to occur fluctuation, occur flicker or light and shade non-uniform phenomenon.In the present embodiment, when external dc power VCC voltage raises, flow through LED, the electric current of feedback resistance R1 increases thereupon, therefore the dividing potential drop of resistance R1 increases, due to reference voltage source V
oUTconstant voltage, therefore the base stage B dividing potential drop of NPN triode Q reduces, its base current I
breduce, NPN triode Q is operated in magnifying state, its collector current I
cwith base current I
blinear, therefore collector current I
calso corresponding reduction.The collector current I of NPN triode Q
cbe the electric current flowing through described LED, the electric current flowing through LED can be suppressed to increase.Otherwise, when DC power supply VCC voltage reduces, flow through the electric current reduction of LED, feedback resistance R1, according to reference voltage source V
oUTthe feedback condition of constant voltage and NPN triode Q, the electric current flowing through LED can be suppressed to reduce, and make when DC power supply VCC voltage fluctuation, the electric current flowing through LED remains unchanged, for LED provides constant current operation electric current.
Meanwhile, the control end output voltage source V of described controller 1
oUTfor providing reference voltage, the electric current that described constant current switch, feedback resistance R1 and LED loop absorb is generally μ A level, therefore can provide compared with weak current signal to drive the function of described LED.Preferably, if need to power to multiple LED or LED array, the loop that the LED of respective numbers, feedback resistance R1, current-limiting resistance R2 and triode Q form can be selected.
Embodiment 2: for light-coupled isolation device
Optocoupler is used to realize input and output electrical isolation, generally arrange photodiode to be realized, photodiode purposes is very wide, can receiving infrared-ray (often supporting the use with infrared-emitting diode), be generally used for automatic optoelectronic switch, infrared touch panel, intelligent appliance etc., for reception environment light.The present embodiment weak-current switch formula constant current driver circuit for LED can be used as the photoelectric yield end of a light-coupled isolation device, it is made up of feedback device, constant current switch and controller, wherein supply voltage access LED, described constant current switch connects LED, and by described feedback device ground connection, described controller connects constant current switch and input control voltage drives above-mentioned LED to control described constant current switch.
As improvement, described constant current switch is NPN type triode Q, and the LED described in its base stage connection control device, collector electrode connect, emitter-base bandgap grading connect feedback device.In the present embodiment, current-limiting resistance R2 can not be used.Constant current switch Q receives the control signal V of constant-current source
oUTcontrol opening and closing to control NPN triode Q and reference voltage source VCC conducting or disconnection, when the Q conducting of NPN triode, reference voltage source V
oUTfor the base stage B of NPN triode Q provides high level to input, form base current, emitter E forms emitter current and flows through ground connection after feedback resistance R1, and the power supply in the current supply circuit of LED is external dc power VCC.
The control end output voltage source V of controller 1
oUTfor providing reference voltage, the electric current that described constant current switch, feedback resistance R1 and LED loop absorb is generally μ A level, therefore can provide compared with weak current signal to drive the function of described LED.
Claims (5)
1. a weak-current switch formula constant current driver circuit for LED, it is characterized in that, it is made up of current limiting device, feedback device, constant current switch and controller, wherein supply voltage is by described current limiting device access LED, described constant current switch connects LED again, and by described feedback device ground connection, described controller connects constant current switch and input control voltage drives above-mentioned LED to control described constant current switch.
2. weak-current switch formula constant current driver circuit for LED according to claim 1, it is characterized in that, described constant current switch is NPN type triode Q, and the LED described in its base stage connection control device, collector electrode connect, emitter-base bandgap grading connect feedback device.
3. weak-current switch formula constant current driver circuit for LED according to claim 2, is characterized in that, described current limiting device is current-limiting resistance R2, and one termination enters supply voltage, and the other end accesses described LED; Described feedback device is feedback resistance R1, and one termination enters described NPN type triode Q, other end ground connection.
4. a weak-current switch formula constant current driver circuit for LED, it is characterized in that, it is made up of feedback device, constant current switch and controller, wherein supply voltage access LED, described constant current switch connects LED, and by described feedback device ground connection, described controller connects constant current switch and input control voltage drives above-mentioned LED to control described constant current switch.
5. weak-current switch formula constant current driver circuit for LED according to claim 4, it is characterized in that, described constant current switch is NPN type triode Q, and the LED described in its base stage connection control device, collector electrode connect, emitter-base bandgap grading connect feedback device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520891962.0U CN205082029U (en) | 2015-11-10 | 2015-11-10 | Weak current switch formula LED constant -current drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520891962.0U CN205082029U (en) | 2015-11-10 | 2015-11-10 | Weak current switch formula LED constant -current drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205082029U true CN205082029U (en) | 2016-03-09 |
Family
ID=55434399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520891962.0U Active CN205082029U (en) | 2015-11-10 | 2015-11-10 | Weak current switch formula LED constant -current drive circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205082029U (en) |
-
2015
- 2015-11-10 CN CN201520891962.0U patent/CN205082029U/en active Active
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20170306 Address after: HOLLEY Technology Park No. 181 310023 Hangzhou city Zhejiang District of Yuhang province Wuchang Avenue Patentee after: HOLLEY METERING LIMITED Address before: Green Ting Road Yuhang District Cang Qian street of Hangzhou city Zhejiang province 310023 No. 1 Building 1 room 179 Patentee before: HANGZHOU YIJU ELECTRONIC TECHNOLOGY CO., LTD. |