High Power Factor Correction For Dimming T8 Led Tube Circuit

• Main Authors: Manh, Tran Van, 陳文錳
• Other Authors: 陳慎銚
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/32g5fe

碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 101 === This thesis introduces an advanced method to get high power factor correction (PFC) with fewer components than the traditional PFC circuits. It also provides an efficient solution to supply power for Light Emitting Diodes (LEDs). High power factor Flyback converter in first stage is completely analyzed by using the controller L6561D. Second stage is Boost converter which is operated by the controller UC3845. UC3845 is the controller for peak current mode control which is suitable with current control devices as LED. Because the duty cycle of UC3845 is changed by PWM signal, the forward current stressed on LED will satisfy the LED’s characteristic such as current and voltage. In addition, the structure of driver and control circuit for T8 – LED tube is also designed and verified in this thesis. A completed prototype helps to measure some waveforms and necessary parameters of this circuit. Finally the experimental results show the improvement of power factor with the variation of PWM signal.