高功率因數(shù)LED T8燈管更換

　　LED燈具替代白熾燈越來越多，但他們有一個偉大的未來取代熒光燈

　　本文介紹的原則和設(shè)計方程所需的高亮度LED燈的設(shè)計使用al9910高壓LED控制器。方程是用來證明一個普遍的，離線設(shè)計，高功率因數(shù)（PF），13瓦LED燈適合使用作為一個T8熒光管的更換。提供了完整的設(shè)計，包括電氣圖、元件清單和性能測量。

　　高功率因數(shù)的al9910降壓LED驅(qū)動器

　　Figure 1 shows the electrical diagram of an offline 13 W LED driver.

　　On the input side， CX1， CX2， CX3， CX4， L1， and L2 provide sufficient filtering for both differential mode and common mode EMI noise generated by the switching converter circuit.

　　The rectified AC line voltage from the bridge rectifier DB1 is then fed into a passive power factor correction or valley-fill circuit， which consists of three diodes and two capacitors. D1， D2， D3， C1， and C2 improve the input line current distortion in order to achieve a PF greater than 0.9 for the AC line input.