Ingalungiswa njani i-Flicker ye-LED?

Ngenxa yokuba kufuneka sazi ukuba zeziphi iindawo zesixokelelwano sokukhanyisa ekufuneka ziphuculwe okanye zitshintshwe, siye sagxininisa indlela ekubaluleke ngayo ukuchonga umthombo wesibane (ngamandla e-AC okanye i-PWM?).

Ukuba iLED STRIPngunobangela wokuqhwanyaza, kuya kufuneka uyitshintshele entsha eyenzelwe ukugudisa amandla e-AC kwaye ayiguqule ibe yi-DC yangoku ezinzileyo, ethi emva koko isetyenziswe ukuqhuba ii-LEDs. Njonga i "flicker free” iziqinisekiso kunye nemilinganiselo ephaphazelayo xa ukhetha umtya we-LED ngokukodwa:

Umahluko olungelelanisiweyo phakathi kowona mgangatho mkhulu kunye nowona mgangatho wokuqaqamba (amplitude) ngaphakathi kumjikelo ophaphazelayo ubonakaliswa njengepesenti yamanqaku abizwa ngokuba yi "flicker percent." Ngokuqhelekileyo, ibhalbhu ye-incandescent iyantlitha phakathi kwe-10% kunye ne-20%. (kuba i-filament yayo igcina ukushisa kwayo ngexesha "leentlambo" kwi-signal ye-AC).

I-Flicker Index yi-metric ebala ubungakanani kunye nobude bexesha apho i-LED ivelisa ukukhanya okungaphezulu kunesiqhelo ngexesha lomjikelo we-flicker. Isalathisi sebhalbhu ye-incandescent yi-0.04.

Izinga apho umjikelo oziphinda-phindayo ngomzuzwana waziwa ngokuba yi-flicker frequency kwaye ibonakaliswa nge-hertz (Hz). Ngenxa yokuphindaphinda kwesignali ye-AC engenayo, uninzi lwezibane ze-LED ziya kusebenza kwi-100-120 Hz. Amanqanaba esalathiso afanayo kunye ne-flicker anokuba neempembelelo ezincinci kwiibhalbhu ezinamaza aphezulu ngenxa yamaxesha okutshintsha akhawulezayo.

Kwi-100-120 Hz, uninzi lwezibane ze-LED ziyaqhwanyaza. I-IEEE 1789 icebisa ukuba i-8% ikhuseleke (“ingozi ephantsi”) iphaphaze ngokuphindaphindiweyo, kunye ne-3% ukuphelisa ngokupheleleyo iziphumo ze-flicker.

Kuya kufuneka kwakhona ubuyisele iyunithi ye-PWM dimmer ukuba i-PWM dimmer okanye isilawuli sisizathu sokuqhwanyaza. Iindaba ezimnandi zezokuba kuba imichilo ye-LED okanye ezinye izinto azinakwenzeka ukuba zibe ngumthombo we-flicker, kuphela i-PWM dimmer okanye isilawuli siya kufuna ukutshintshwa.

Xa ukhangela isisombululo se-PWM esingafihlisiyo, qiniseka ukuba kukho umlinganiselo ocacileyo wokuphindaphinda kuba yeyona nto iluncedo kwi-PWM flicker metric (kuba idla ngokuba ngumqondiso one-100% flicker). Sicebisa ukuphindaphinda kwe-PWM ye-25 kHz (25,000 Hz) okanye ngaphezulu kwisisombululo se-PWM esingenakuqhwanyaza ngokwenene.

Ngapha koko, imigangatho efana ne-IEEE 1789 ibonisa ukuba imithombo yokukhanya ye-PWM ene-frequency ye-3000 Hz yi-frequency ephezulu ngokwaneleyo yokunciphisa ngokupheleleyo iimpembelelo ze-flicker. Nangona kunjalo, enye inzuzo yokunyusa i-frequency ngaphezulu kwe-20 kHz kukuba iyawasusa amandla ezixhobo zokubonelela ngombane ukwenza izandi ezivakalayo okanye ezikhalayo. Isizathu soku kukuba eyona frequency evakalayo evakalayo kubantu abaninzi yi-20,000 Hz, ngoko ngokuchaza into kwi-25,000 Hz, umzekelo, unokunqanda ukubakho kwezandi ezicaphukisayo okanye ezikhalayo, ezinokuba yingxaki ukuba unovelwano okanye ukuba isicelo sakho sinovakalelo kakhulu.