Research on PWM Control Circuit Design for Color Temperature of RGB LEDs

[[abstract]]本文主要針對，紅、綠、藍三原色發光二極體(Light Emitting Diode, LED)之光電 特性進行探討。將LED以DC直流驅動模式與PWM脈波寬度調變模式二種不同電壓、電流 與脈波波形驅動，同時進行調光，分析其電氣與發光特性；包括發光效率、光譜能量 以及色度(CCT)與演色性(CRI)影響。經本文分析，LED操作特性受DC驅動電流與PWM 脈波寬度調變影響而有所差異；分析DC直流模式與PWM脈波寬度調變模式下LED參數值、 色度(CCT)與演色性(CRI)偏移影響。對此，本文提出已脈波寬度調變 (Pulse Width M odulation, PWM)搭配定電流控制模式(Current Control Mode )、自動電流控制回授 模式(Automatic -Current Control Mode)與自動電功率控制回授模式(Automatic-E lectric Power Control Mode)進而進行調光試驗，藉以穩定LED參數之演色性和色度 CCT與LED相關特性參數值。[[abstract]]This thesis will mainly focus on discussion of full color LED operating characteristics. Let LEDs use DC Level driving and Pulse Width Modulation, PWM each with two different voltages, currents, and pulse waves, to undergo Blight Dimming at the same time; to analyze electric characteristics and emitting characteristics including: emitting efficiency, spectrum energy, and effects on CCT and CRI. After analysis, differences in LED operating characteristics are affected by driving current. LED with PWM undergoes BL dimming. During analysis of DC Level driving and Pulse Width Modulation, PWM , LED color chromaticity (CCT) and color rendering index (CRI) offset. Thus this thesis propose using Current Control Mode ,Automatic-Current Control Mode and Automatic-Electric Power Control Mode to undergo Blight Dimming experiment, to therefore stabilize LED of CRI ,CCT and LED-related parameter value.[[note]]碩