CN203416450U

CN203416450U - Flicker-eliminating LED drive circuit

Info

Publication number: CN203416450U
Application number: CN201320092293.1U
Authority: CN
Inventors: 王文君; 陈佳; 范茂
Original assignee: CHENGDU MAOYANG ELECTRONICS TECH Co Ltd
Current assignee: CHENGDU MAOYANG ELECTRONICS TECH Co Ltd
Priority date: 2013-02-28
Filing date: 2013-02-28
Publication date: 2014-01-29
Anticipated expiration: 2023-02-28

Abstract

A flicker-eliminating LED drive circuit relates to electronic technology. The flicker-eliminating LED drive circuit comprises an AC input terminal and a first set of driver modules with no electrolytic capacitor. The improved stroboscopic LED drive circuit is characterized by also comprising a phase shift circuit module and a second set of driver modules with no electrolytic capacitor, and the second set of driver modules is connected with the AC input terminal through the phase shift circuit module. According to the flicker-eliminating LED drive circuit, the double AC commercial power frequency stroboscopic condition in LED illumination without electrolytic capacitor is eliminated, the illumination quality is improved, the LED driving scheme without electrolytic capacitor can be applied to many occasions such as tunnel illumination and security illumination.

Description

A kind of stroboscopic LED drive circuit that improves

Technical field

The utility model relates to electronic technology.

Background technology

LED is a kind of novel semiconductor lighting technology, has advantages of that the traditional lightings such as incandescent lamp are incomparable: luminous efficiency high, photochromic good, reliability is high, the life-span is long etc.Since entering 21 century, particularly after 2010, along with the continuous progress of technology and the reduction of cost, LED light on, enters large-scale commercial stage.LED one of the attractive spot that throws light on, is its long-life, high reliability.But because it need adopt DC power supply, and such DC power supply comprises electrochemical capacitor conventionally, so that the effect of rectifying and wave-filtering to be provided.Electrochemical capacitor is due to the particularity of its structure, life-span is conventionally not long, seldom there is the rated life time to surpass the electrochemical capacitor of 10000 hours, this and the LED life time of tens thousand of even 100,000 hours does not very mate, the heat dissipation that adds LED is very big, cause the electrochemical capacitor operating ambient temperature of driving power very high, its life-span can further reduce.If therefore do not solve the life problems of electrochemical capacitor, the long-life advantage of LED illumination is just difficult to bring into play, affects it and promotes the use of.Therefore, on market, rise now a kind of LED drive scheme of no electrolytic capacitor, be LED and provide in the DC power supply of power supply and do not adopt electrochemical capacitor, with this, reached the long-life object of whole LED lighting module.But there is a problem in such drive scheme: because DC power supply has been removed the big capacity electrolyte capacitor for elementary filtering, the supply power voltage of LED and electric current have larger ripple, be mainly that frequency is that ripple ，Yi China 50HZ Alternating Current Power Supply of twice power frequency is example, ripple frequency is 100HZ.Although the LED of 100HZ flicker human eye is invisible in theory, but in the strict occasion of ask for something, still cannot accept the to throw light on stroboscopic of 100HZ, because this flicker can bring flash effect, the multiple video that there will be moving object when photography, this may cause security camera to lose important picture.Have part viewpoint to think, the stroboscopic of 100HZ can shine into impact to the health of human body simultaneously, it is reported, illumination 100HZ stroboscopic may cause that groups of people are dizzy, eyes strain, and antimigraine also may increase the danger of apoplexy.So improve the research direction that stroboscopic has become no electrolytic capacitor LED to drive.

Utility model content

Technical problem to be solved in the utility model is that a kind of drive circuit that can improve and eliminate the stroboscopic situation of no electrolytic capacitor driving LED is provided.

The technical scheme that the utility model solve the technical problem employing is, improve stroboscopic LED drive circuit, comprise alternating current input and first group of no electrolytic capacitor driver module, it is characterized in that, also comprise phase-shift circuit module, and the second group of no electrolytic capacitor driver module being connected with alternating current input by phase-shift circuit module.

First group of no electrolytic capacitor driver module and second group of no electrolytic capacitor driver module comprise the no electrolytic capacitor driver module that quantity is equal; First group of no electrolytic capacitor driver module directly connects alternating current input.The phase shifts value of phase-shift circuit module is 90 °.Each no electrolytic capacitor driver module is connected with a LED module.

Further, also have the 3rd group or other no electrolytic capacitor driver modules of more groups to connect alternating current input by phase-shift circuit module, phase shifts value of each group is respectively the equal branch of 180 °.

The beneficial effects of the utility model are, eliminated the situation of no electrolytic capacitor LED illumination twice electric main frequency stroboscopic, improved luminous mass, make no electrolytic capacitor LED drive scheme can be applied to more occasion, particularly make no electrolytic capacitor LED can be applied to the special lighting markets such as tunnel illumination, security protection illumination.Eliminate the impact that common no electrolytic capacitor LED twice mains frequency stroboscopic may cause health simultaneously.

Accompanying drawing explanation

Fig. 1 is the voltage oscillogram of electric main.

Fig. 2 is the voltage oscillogram after full-bridge rectification.

Fig. 3 is line voltage waveform and the voltage oscillogram of civil power after 90 ° of phase shifts.

After 90 ° of phase shifts of waveform after Fig. 4 civil power full-bridge rectification and civil power again through the contrast of the voltage oscillogram of rectification.

Fig. 5 is the LED drive current waveform of common no electrolytic capacitor LED, and the frequency of envelope is twice mains frequency.

Fig. 6 is structured flowchart of the present utility model.

Fig. 7 is the structured flowchart of embodiment.

Fig. 8 is the circuit diagram of no electrolytic capacitor driver module.

Fig. 9 is the drive current waveform comparison diagram of two LED luminescence units.

Embodiment

After civil power input rectifying, there is no jumbo electrochemical capacitor filtering, is the main cause that causes no electrolytic capacitor stroboscopic.Fig. 1 is that alternating voltage waveform ，Yi China of civil power input is example, and civil power is 220V, the alternating current of 50Hz.Fig. 2 be after civil power input through the voltage waveform of full-bridge rectification, after rectification, 2 Bei，Yi China that the frequency of voltage waveform becomes mains frequency are example, become 100Hz.For conventionally can there is the no electrolytic capacitor LED drive waveforms of 2 times of mains frequency stroboscopics in Fig. 5; the waveform of drive current is envelope shape; the rise and fall of envelope with civil power the waveform after full-bridge rectification consistent; civil power is after full-bridge rectification; do not have jumbo electrochemical capacitor to carry out filtering processing; only have thin-film capacitor or the ceramic condenser of low capacity to do simple filtering processing, waveform is approximately waveform shown in Fig. 2.When the voltage waveform of civil power after full-bridge rectification approaches 0V to trough, the electric current of LED also will drop to and approach zero, as shown in electric current envelope the lowest point in figure.And the luminosity of LED is determined by its drive current, electric current is larger, and brightness is higher.Thereby this electric current envelope can cause that the flicker of twice mains frequency occurs LED.Although this frequency, not in the visible range of human eye, but still can cause potential impact to health, needs the occasion of high reliability at some, such as street lamp, instrument illumination etc., the stroboscopic of 100Hz is also unacceptable.

The stroboscopic LED drive circuit that improves the utility model proposes comprises alternating current input and first group of no electrolytic capacitor driver module, also comprise phase-shift circuit module, and the second group of no electrolytic capacitor driver module being connected with alternating current input by phase-shift circuit module.

First group of no electrolytic capacitor driver module and second group of no electrolytic capacitor driver module comprise the no electrolytic capacitor driver module that quantity is equal; First group of no electrolytic capacitor driver module directly connects alternating current input.The phase shifts value of phase-shift circuit module is 90 °, offset of sinusoidal ripple civil power.

Each no electrolytic capacitor driver module is connected with a LED module.

Also can comprise that the 3rd group or other no electrolytic capacitor driver modules of more groups connect alternating current input by phase-shift circuit module, it is the equal branch of 180 ° that each pack module exchanges the phase difference of input after phase shift block phase shift again.In intensity of illumination, realize a plurality of waveform stacks, make the waveform after stack level and smooth as far as possible, thereby eliminate stroboscopic phenomenon.

Concrete execution mode is referring to Fig. 6.The overall luminescence unit of no electrolytic capacitor LED system of the present utility model comprises two or more LED modules (LED module A1～An, LED module B1～Bn), these LED modules are independently, by no electrolytic capacitor driver module separately, drive (no electrolytic capacitor driver module A1～no electrolytic capacitor driver module An, no electrolytic capacitor driver module B1～Bn) respectively.No electrolytic capacitor driver module is that the common 100Hz(that can occur be take China as example) the no electrolytic capacitor drive circuit of stroboscopic, wherein comprise full-bridge filter circuit, AC/DC change-over circuit etc., as Fig. 8.

Phase-shift circuit module of the present utility model is for carrying out 90 ° of phase shifts by electric main, and Fig. 3 is line voltage waveform and the voltage waveform of civil power after 90 ° of phase shifts.Phase-shift circuit module can be common RC phase-shift circuit, the phase shift block of phase shifting transformer and directly purchase etc.No electrolytic capacitor driver module A1～no electrolytic capacitor driver module An is called first group of no electrolytic capacitor driver module, by electric main, directly inputs power supply; No electrolytic capacitor driver module B1～no electrolytic capacitor driver module Bn is called second group of no electrolytic capacitor driver module, and the alternating voltage by electric main after 90 ° of phase shifts of phase-shift circuit module is powered.

Of the present utility modelly by electric main no electrolytic capacitor driver module A1～no electrolytic capacitor driver module An that directly powers, equated with the no electrolytic capacitor driver module B1～no electrolytic capacitor driver module Bn number by powering after electric main phase shift, in other words, two groups of driver modules with same quantity; And " LED module A1 " to " LED module An " and " LED module B1 " are that brightness equates to " LED module Bn " average canbdle power.Best implementation method is, " no electrolytic capacitor driver module A1～n " and " no electrolytic capacitor driver module B1～n " corresponds to identical module one by one, and " LED module A1～n " and " LED module B1～n " corresponds to identical module one by one." LED module A1 " is the same with " LED module B1 " luminous intensity, " LED module An " is the same with " LED module Bn " luminous intensity, and " LED module A1 " forms " the overall luminescence unit " of the no electrolytic capacitor LED that has eliminated the flicker of twice mains frequency after mixed light is processed to " LED module An " and " LED module B1 " to " LED module Bn "." overall luminescence unit " determines final illuminating effect.

Fig. 7 is the basic structure of the utility model one embodiment, embodiment comprises two groups of LED modules " LED module A " and " LED module B " altogether, by " no electrolytic capacitor driver module A " and " no electrolytic capacitor driver module B ", driven respectively, " no electrolytic capacitor driver module A " directly powered by electric main, and " no electrolytic capacitor driver module B " be the AC-powered after " phase-shift circuit/module " 90 ° of phase shifts by electric main." LED module A " and " LED module B " is duplicate module, and " no electrolytic capacitor driver module A " and " no electrolytic capacitor driver module B " is duplicate module." LED module A " is identical with the drive current envelope of " LED module B ", and just phase phasic difference is 180 °, and average canbdle power is the same.

Accompanying drawing 8 is " no electrolytic capacitor driver module A " and " the no electrolytic capacitor driver module B " internal circuit diagram in embodiment basic structure.In driver module, not containing electrochemical capacitor, all electric capacity is CBB thin-film capacitor or ceramic condenser, has realized no electrolytic capacitor design.The basic structure of circuit is universal inverse-excitation type no electrolytic capacitor LED drive circuit, and the core of circuit is controlled by " control chip " of certain domestic model and realized.The functions such as the Current Control of " control chip " realization " N-channel MOS FET ", the Duty ratio control of driving, LED drive current adjustment." no electrolytic capacitor driver module A " is input as electric main." no electrolytic capacitor driver module B " is input as the alternating current of electric main after 90 ° of phase shifts.Their output meets respectively LED module " LED module A " and " LED module B " separately." LED module A " and " LED module B " forms " the total luminescence unit of LED " after optics mixed processing, and " the total luminescence unit of LED " determines final illuminating effect.

The course of work of the present embodiment is after civil power input, to be divided into two-way ，Yi road and to be directly inputted to no electrolytic capacitor driver module A; Another road is input to phase-shift circuit/module, after 90 ° of phase shifts are processed, then is input to " no electrolytic capacitor driver module B ".Again respectively by " no electrolytic capacitor driver module A " and " no electrolytic capacitor driver module B " driving " LED module A " and " LED module B ".Accompanying drawing 9 is the drive current waveform of " LED module A " and " LED module B ", and waveform is identical electric current envelope, and just phase phasic difference is 180 °.When " LED module A " drive current waveform is during at trough, " LED module A " luminous intensity is minimum, and now " LED module B " drive current waveform is just in crest, and " LED module B " luminous intensity is maximum; When " LED module A " drive current waveform is during at crest, " LED module A " luminous intensity is maximum, and now " LED module B " drive current waveform is just in trough, and " LED module B " luminous intensity is minimum.And the luminosity of " the overall luminescence unit of LED " is by total drive current decision of " LED module A " and " LED module B ", the average canbdle power of " the overall luminescence unit of LED " is substantially constant, can not be subject to after AC rectification the impact without big capacity electrolyte capacitor filtering.Eliminated the stroboscopic of 2 times of mains frequencies.

Claims

1. one kind is improved stroboscopic LED drive circuit, comprise alternating current input and first group of no electrolytic capacitor driver module, it is characterized in that, also comprise phase-shift circuit module, and the second group of no electrolytic capacitor driver module being connected with alternating current input by phase-shift circuit module.

2. the stroboscopic LED drive circuit that improves as claimed in claim 1, is characterized in that, first group of no electrolytic capacitor driver module and second group of no electrolytic capacitor driver module comprise the no electrolytic capacitor driver module that quantity is equal; First group of no electrolytic capacitor driver module directly connects alternating current input.

3. the stroboscopic LED drive circuit that improves as claimed in claim 1, is characterized in that, the phase shifts value of phase-shift circuit module is 90 °.

4. the stroboscopic LED drive circuit that improves as claimed in claim 1, is characterized in that, each no electrolytic capacitor driver module is connected with a LED module.

5. the stroboscopic LED drive circuit that improves as claimed in claim 1, it is characterized in that, also have the 3rd group or other no electrolytic capacitor driver modules of more groups to connect alternating current input by phase-shift circuit module, phase shifts value of each group is respectively the equal branch of 180 °.