Brightness Control of a LED Lamp by Pulse Width Modulation

• Main Authors: Po-Chao Chang, 張博超
• Other Authors: Yeeu-Chang Lee
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/20366693071973348135

碩士 === 中原大學 === 機械工程研究所 === 98 === A controlled system of house LED lighting was developed in this study. For the hardwares , a single chip microcontroller was used to integrate the functions of both lamps and touch panel modules. The man-machine interface of touch panel including a touch screen and a LCD monitor, which replaces the conventional switch. The 24 volts,100~400 mA are the operation conditions of LED lamps with driving circuit. For the control method, PWM (Pulse Width Modulation) was used to adjust the duty cycle to control the electrical power between fully on and fully off. From the experimental results, the brightness of high power LED lamp is directly proportional to the input currents. The brightness of LED lamp can be also controlled by PWM meanwhile PWM control has minor effect on the shift color temperature compared to that of direct current operation. Therefore,PWM is a better solution to control the brightness of LED lamps.