新的解決方案提高LED照明的調(diào)光性能

　　最大的挑戰(zhàn)之一，LED照明設(shè)計師所面對的是在可控硅調(diào)光器的LED燈的調(diào)光性能。在許多情況下，與白熾燈泡相比，這會導(dǎo)致閃爍和降低亮度范圍。問題是，可控硅調(diào)光器的設(shè)計基于使用的白熾燈，具有電阻性負(fù)載。當(dāng)LED開始被使用的調(diào)光器，低電流的要求，隨著器件的非電阻，使雙向晶閘管間歇地打開和關(guān)閉，造成閃爍的效果。

　　LED和LED驅(qū)動器是非電阻性負(fù)載，其輸入電流通常低于控股的可控硅調(diào)光器的電流。這會導(dǎo)致閃爍和有限的調(diào)光范圍。

　　LED驅(qū)動器制造商已經(jīng)開發(fā)出新的解決方案來解決這個閃爍的問題。一種方式是通過將放氣和LED驅(qū)動電路的阻尼。什么樣的分壓電路是保證輸入電流大于保持雙向晶閘管的電流限制。阻尼電路的“抑”的電流振蕩，這也有助于閃爍。

　　This article will examine several available LED driver ICs and designs that will help deliver flicker-free and fast startup dimming performance while still providing high power factor， high efficiency， and low THD for good lighting performance.

　　“These TRIAC wall-based dimmers were designed to work with incandescent bulbs， which are rated to operate at higher power levels and are resistive，” said Rakesh Anumula， applications engineer at Intersil Corp. “When migrating from incandescent bulbs to either CFLs or LED lighting， the load isn‘t resistive anymore， but it’s inductive or capacitive， so the dimmer doesn‘t behave the same way as would with an incandescent bulb.”