CN104066244A - Universal LED simulation dimming circuit - Google Patents
Universal LED simulation dimming circuit Download PDFInfo
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- CN104066244A CN104066244A CN201410266115.5A CN201410266115A CN104066244A CN 104066244 A CN104066244 A CN 104066244A CN 201410266115 A CN201410266115 A CN 201410266115A CN 104066244 A CN104066244 A CN 104066244A
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Abstract
The invention relates to a universal LED simulation dimming circuit which comprises an active low-pass filter, an amplifier, a voltage regulator and a linear optical coupler circuit, wherein the active low-pass filter, the amplifier, the voltage regulator and the linear optical coupler circuit are connected in series sequentially. The universal LED simulation dimming circuit is suitable for simulation dimming of most LED constant current drive circuits and particularly suitable for the occasion that LED drive chips in the constant current drive circuits are not provided with dimming interfaces but lamps need dimming.
Description
Technical field
The invention belongs to LED lighting field.The present invention is directed in some high power LED constant-current driving circuits it and drive chip not possess the problem of dimming interface, proposed a kind of general LED analog light-adjusting circuit applied widely.
Background technology
(1) as shown in Figure 1, the LED that this scheme need to this circuit drives chip to have dimming interface to the major programme that at present LED drive circuit is realized light modulation:
This scheme be utilize LED drive chip itself with dimming interface realize dimming function, as shown in Figure 1, LED drives the PWM dimming interface of chip to receive the adjustable pwm signal of duty ratio by the size of current of LED drive circuit for adjusting after the processing of circuit of chip internal; Same LED drive chip utilization with simulation dimming interface receive the adjustable analog voltage signal of LINEAR CONTINUOUS and realize the adjusting for LED drive circuit electric current.
(2) in the practical application of LED drive circuit, have a lot of widely used LED to drive chips not there is dimming interface (no matter being PWM interface or simulation dimming interface), the LED drive scheme common structure driving based on this class LED as shown in Figure 2:
This drives main circuit generally comprises EMI filter circuit, input rectifying filter circuit, circuit of power factor correction, DC/DC translation circuit, output filter circuit etc., and feedback control circuit generally comprises output sampling comparison, LED drives chip etc.DC/DC translation circuit in main circuit can adopt the various topological structures such as flyback, normal shock, Boost, Buck.The implementation of drive circuit constant current output is generally: in feedback path, the sampled value of output current is compared by the comparator constant reference voltage corresponding with setting output current with, the Output rusults of comparator feeds back to LED and drives chip, drive chip to go to adjust in real time DC/DC translation circuit according to certain rule, thereby make outputting current steadily in set point.Because LED drives chip without dimming interface, so this drive scheme can be realized constant current output, but cannot realize the variation of output current, also just cannot realize the light modulation of LED.
In sum, drive the drive circuit that forms of chip for not possessing dimming interface LED, cannot realize the light modulation demand of LED, this is just that the brightness adjustment control of LED drive circuit has been brought inconvenience, has restricted the extensive use of this class LED drive scheme.
Summary of the invention
The problem existing in order to solve above-mentioned prior art, the present invention aims to provide a kind of general LED analog light-adjusting circuit, in the existing great power LED constant current drive scheme of not supporting dimming function, add the circuit of LED simulation light modulation, possess on the basis of primary circuit feature and realize dimming function, this LED analog light-adjusting circuit should have stronger versatility and good isolating power, thereby improves the range of application of great power LED drive scheme.
For achieving the above object, the present invention adopts following technical proposals: a kind of general LED analog light-adjusting circuit, it is characterized in that comprising active low-pass filter, amplifier, voltage regulator circuit and the linear optical coupling circuit of series connection successively, the unadjustable reference voltage of current feedback passage in LED drive circuit current regulator is converted into new adjustable reference voltage, thereby regulate the set point of constant current in LED constant current driving, realize simulation light modulation.
In above-mentioned a kind of general LED analog light-adjusting circuit, described active low-pass filter comprises a resistance R 1, a capacitor C 2 and an operational amplifier UB, wherein the constant reference voltage of resistance R 1 and input is connected, capacitor C 1 one end is connected with resistance R 1, other end ground connection, capacitor C 1 is connected with the positive input terminal of operational amplifier UB with the common port of resistance R 1, and negative input end and the output of operational amplifier UB connect and compose voltage follower; Described amplifier comprises four resistance R 2, R3, R4, R5, a capacitor C 2, and operational amplifier UA, wherein resistance R 2 is received the positive input terminal of operational amplifier UA after being connected with the output of active low-pass filter, ground connection after the negative input end of operational amplifier UA is connected with resistance R 3, the output of operational amplifier UA is connected with R4, and the negative input end of receiving operational amplifier UA of then connecting with R5 in parallel and C2 forms amplifier; Described voltage regulator circuit comprises a potentiometer R6, and potentiometer R6 one end is connected with resistance R 4, the other end with the anodic bonding of the light-emitting diode of linear optical coupling U1 inside; Described linear optical coupling circuit comprises a linear optical coupling U1 and a resistance R 7, wherein the collector electrode of the phototransistor of linear optical coupling inside and the output of active filter connect, the emitter of phototransistor connects with one end of resistance R 7, the other end ground connection of resistance R 7.The common port of the transmitter of photodiode and resistance R 7 is output, output adjustable reference voltage.
Owing to having adopted active low-pass filter in the present invention, not only can make the reference voltage of output more stable, and there is better load matched ability; The present invention has adopted proportional amplifier, and original less reference voltage is amplified, and has not only improved adjustable extent and light modulation precision, also has larger drive current; The present invention has adopted linear optical coupling circuit, can directly realize the reduction in proportion of ratio amplifying element, has saved follow-up ratio and has dwindled circuit, has simplified whole circuit design, has improved reliability; And can also play good buffer action.
The present invention compared with prior art, there is following apparent outstanding substantive distinguishing features and significantly technological progress: the invention solves LED and drive chip itself not possess the problem of the LED drive scheme light modulation of dimming interface, just can realize simulation dimming function by adopting said method as long as there is current settings comparison module in circuit feedback loop.Have good versatility, circuit structure is simple, and good reliability is easy to adjust, is with a wide range of applications.
Brief description of the drawings
Fig. 1 chip is with the Dimmable LED drive scheme figure of dimming interface
Fig. 2 chip can not dimming LED (Light Emitting Diode) drive scheme figure without dimming interface
Fig. 3 adds the LED drive scheme figure of analog light-adjusting circuit
Fig. 4 analog light-adjusting circuit structured flowchart of the present invention
Fig. 5 adds the LED drive circuit schematic diagram of analog light-adjusting circuit
Fig. 6 analog light-adjusting circuit schematic diagram of the present invention.
Embodiment
Embodiment mono-:
Referring to Fig. 4, this general LED analog light-adjusting circuit comprises active low-pass filter, amplifier, voltage regulator circuit and the linear optical coupling circuit of series connection successively, the unadjustable reference voltage of current feedback passage in LED drive circuit current regulator is converted into new adjustable reference voltage, thereby regulate the set point of constant current in LED constant current driving, realize simulation light modulation.
Embodiment bis-:
Referring to Fig. 6, the present embodiment and embodiment mono-are basic identical, special feature is: described active low-pass filter comprises a resistance R 1, a capacitor C 2 and an operational amplifier UB, wherein the constant reference voltage of resistance R 1 and input is connected, and capacitor C 1 one end is connected with resistance R 1, other end ground connection, capacitor C 1 is connected with the positive input terminal of operational amplifier UB with the common port of resistance R 1, and negative input end and the output of operational amplifier UB connect and compose voltage follower.Make reference voltage more stable, there is better load matched ability.
Described amplifier comprises four resistance R 2, R3, R4, R5, a capacitor C 2, and operational amplifier UA, wherein resistance R 2 is received the positive input terminal of operational amplifier UA after being connected with the output of active low-pass filter, ground connection after the negative input end of operational amplifier UA is connected with resistance R 3, the output of operational amplifier UA is connected with R4, then the negative input end of receiving operational amplifier UA of connecting with R5 in parallel and C2 forms amplifier, original low reference voltage is enlarged into higher voltage, multiplication factor is determined by resistance R 3 and R4, not only improve adjustable extent, also there is larger drive current.
Described linear optical coupling circuit comprises a linear optical coupling U1 and a resistance R 7, wherein the collector electrode of the phototransistor of linear optical coupling circuit (4) inside connects with the output of active low-pass filter (1), the emitter of this phototransistor connects with one end of resistance R 7, the other end ground connection of resistance R 7; The emitter of this phototransistor connects with the common port of resistance R 7 for output, output adjustable reference voltage.
Below, by reference to the accompanying drawings, to a preferred embodiment of the present invention will be described in detail.
Embodiment tri-:
As shown in Figure 4, in analog light-adjusting circuit module, comprise following components: active low-pass filter (1), reference voltage amplifier (2), voltage regulator (3), linear optical coupling circuit (4).
The specific works principle of LED analog light-adjusting circuit is as shown in Figure 6: described active low-pass filter is by a resistance R 1, a capacitor C 2 and an operational amplifier UB composition, the constant reference voltage of input is carried out filtering by this active low-pass filter, makes constant reference voltage more stablize and improve the matching capacity of its load;
Described amplifier is by four resistance R 2, R3, R4, R5, a capacitor C 2, and operational amplifier UA composition.Amplifier amplifies with the filtered constant reference voltage of process active low-pass filter, multiplication factor is determined by resistance R 3 and R4, constant reference voltage after amplification has better adjustment width, after potentiometer R6 regulates, carry out dwindling of corresponding proportion by linear optical coupling circuit, after this process, just can export adjustable reference voltage.
the specific works process of circuit of the present invention
Example of the present invention, according to accompanying drawing 5 incoming transport civil powers, is then adjusted to maximum position by the potentiometer R109 of simulation light modulation, and energising can normally be worked.Regulator potentiometer R109, the i.e. brightness of adjustable LED lamp.
Alternating current has passed through EMI filter circuit 1 after inputting into, and inductance L 2 is for eliminating common mode disturbances, and capacitor C 1, C2 have eliminated differential mode interference; Eliminated alternating current after disturbing is converted into pulsation direct current through rectification circuit 2, the direct current of pulsation, after capacitor C 3 filtering and voltage-stabiliser tube Z1, forms a level and smooth direct voltage;
LED drives chip 3 to obtain the voltage waveform of inputting after rectification, the current waveform that obtains input by AC IN pin by pin VFF and pin FB, carries out power factor correction through chip internal standard signal generator, low-frequency voltage regulating error amplifier, harmonic compensation and current shaping network to driving;
Voltage after rectification is input in the primary coil of transformer, carry out energy storage, the peak voltage that primary clamp circuit 4 produces for absorbing the reflected voltage of transformer secondary output coil and the leakage inductance of primary coil, prevents that power MOSFET from bearing too high peak voltage in the time turn-offing; In order to drive chip 3 to power to LED, introduce voltage by the auxiliary winding of transformer, process chip power supply circuit 5 is by the VCC pin of stable 14.5V voltage access chip;
Voltage is exported to load through transformer secondary output winding after output filter circuit 6, then reaches the object of drive circuit constant pressure and flow by output voltage detecting circuit 8, output current detection circuit 7, constant pressure and flow control circuit 9 and optocoupler feedback circuit 10: output voltage detecting circuit 8 is input to voltage ratio in constant pressure and flow control circuit 9 by electric resistance partial pressure by detectable voltage signals and holds with the reference voltage of 2.5V and compare; Output current detection circuit 7 is by carrying out being input to after dividing potential drop and filtering are processed current ratio in constant pressure and flow control circuit 9 and hold with adjustable reference voltage and compare detecting the voltage at resistance R 26 two ends.Comparative result accesses LED by optocoupler feedback circuit 10 and drives chip 4 to form the closed-loop control of voltage, electric current, by output voltage, outputting current steadily in the set point corresponding with benchmark voltage separately.
The 2.5V fixed reference voltage that described analog light-adjusting circuit 11 is held voltage ratio in constant pressure and flow control circuit 9 carries out filtering by active low-pass filter circuit, then amplify through amplifier, the voltage signal of 10V will be become after the reference voltage quadruplication of original 2.5V, then the voltage regulator circuit consisting of potentiometer R109 carries out dividing potential drop adjusting to 10V voltage, to export the adjustable voltage of 1V ~ 10V.Changing this voltage can change by the size of the electric current of light-emitting diode in linear optical coupling circuit, thereby regulate the luminosity of light-emitting diode, flow through the also linear change with the brightness variation of light-emitting diode of electric current of phototransistor, because the feeder ear of phototransistor is also directly taken from active low-pass filter circuit output, for stable 2.5V, so the voltage at resistance R 110 two ends also changes between 2.5V at 0.25V, in this voltage access constant-current and constant-voltage control circuit 9 electric current another relatively hold as reference voltage, thereby can pass through regulator potentiometer R109, regulation output current setting value in real time, just can realize in this way the dimming function of this high-power drive circuit.
Claims (4)
1. a general LED analog light-adjusting circuit, it is characterized in that: the active low-pass filter (1), amplifier (2), voltage regulator circuit (3) and the linear optical coupling circuit (4) that comprise series connection successively, the unadjustable reference voltage of current feedback passage in LED drive circuit current regulator is converted into new adjustable reference voltage, thereby regulate the set point of constant current in LED constant current driving, realize simulation light modulation.
2. general LED analog light-adjusting circuit claimed in claim 1, it is characterized in that: described active low-pass filter (1) comprises a resistance R 1, a capacitor C 2 and an operational amplifier UB, wherein the constant reference voltage of resistance R 1 and input is connected, capacitor C 1 one end is connected with resistance R 1, other end ground connection, capacitor C 1 is connected with the positive input terminal of operational amplifier UB with the common port of resistance R 1, and negative input end and the output of operational amplifier UB connect and compose voltage follower; Make reference voltage more stable, there is better load matched ability.
3. general LED analog light-adjusting circuit claimed in claim 1, it is characterized in that: described amplifier (2) comprises four resistance R 2, R3, R4, R5, a capacitor C 2, and operational amplifier UA, wherein resistance R 2 is received the positive input terminal of operational amplifier UA after being connected with the output of active low-pass filter, ground connection after the negative input end of operational amplifier UA is connected with resistance R 3, the output of operational amplifier UA is connected with R4, then the negative input end of receiving operational amplifier UA of connecting with R5 in parallel and C2 forms amplifier, original low reference voltage is enlarged into higher voltage, multiplication factor is determined by resistance R 3 and R4, not only improve adjustable extent, also there is larger drive current.
4. general LED analog light-adjusting circuit claimed in claim 1, it is characterized in that: described linear optical coupling circuit (4) comprises a linear optical coupling U1 and a resistance R 7, wherein the collector electrode of the phototransistor of linear optical coupling circuit (4) inside connects with the output of active low-pass filter (1), the emitter of this phototransistor connects with one end of resistance R 7, the other end ground connection of resistance R 7; The emitter of this phototransistor connects with the common port of resistance R 7 for output, output adjustable reference voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410266115.5A CN104066244A (en) | 2014-06-16 | 2014-06-16 | Universal LED simulation dimming circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410266115.5A CN104066244A (en) | 2014-06-16 | 2014-06-16 | Universal LED simulation dimming circuit |
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| CN104066244A true CN104066244A (en) | 2014-09-24 |
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| CN201410266115.5A Pending CN104066244A (en) | 2014-06-16 | 2014-06-16 | Universal LED simulation dimming circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104883773A (en) * | 2015-04-21 | 2015-09-02 | 阳亮 | Single-stage multi-output LED power supply constant current drive circuit |
| CN106211468A (en) * | 2016-08-19 | 2016-12-07 | 盐城工学院 | A kind of LED drive circuit |
| CN109982485A (en) * | 2019-04-16 | 2019-07-05 | 深圳市豪恩智能物联股份有限公司 | Constant current output adjusts circuit |
| CN112383717A (en) * | 2020-11-12 | 2021-02-19 | 安波福电子(苏州)有限公司 | Current-adjustable infrared light supplement control circuit and DMS camera with same |
| CN114126142A (en) * | 2021-11-05 | 2022-03-01 | 深圳市瑞晶实业有限公司 | Trinity dimmer circuit of output current precision is adjusted in area |
-
2014
- 2014-06-16 CN CN201410266115.5A patent/CN104066244A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104883773A (en) * | 2015-04-21 | 2015-09-02 | 阳亮 | Single-stage multi-output LED power supply constant current drive circuit |
| CN104883773B (en) * | 2015-04-21 | 2017-07-25 | 阳亮 | A kind of single-stage multiple-channel output LED power constant-current drive circuit |
| CN106211468A (en) * | 2016-08-19 | 2016-12-07 | 盐城工学院 | A kind of LED drive circuit |
| CN106211468B (en) * | 2016-08-19 | 2018-02-02 | 盐城工学院 | A kind of LED drive circuit |
| CN109982485A (en) * | 2019-04-16 | 2019-07-05 | 深圳市豪恩智能物联股份有限公司 | Constant current output adjusts circuit |
| CN112383717A (en) * | 2020-11-12 | 2021-02-19 | 安波福电子(苏州)有限公司 | Current-adjustable infrared light supplement control circuit and DMS camera with same |
| CN114126142A (en) * | 2021-11-05 | 2022-03-01 | 深圳市瑞晶实业有限公司 | Trinity dimmer circuit of output current precision is adjusted in area |
| CN114126142B (en) * | 2021-11-05 | 2024-02-13 | 深圳市瑞晶实业有限公司 | Three-in-one dimming circuit with output current precision adjustment function |
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Application publication date: 20140924 |