发光二极管(LED)的结温变化、老化等问题会导致色温、色度等参数的漂移,目前的模拟调光和脉冲宽度调制(PWM)调光方式都不能解决这一问题,研究发现平均电流影响光通量,峰值电流影响色温,因此提出了一种PWM 和脉冲幅度调制(PAM)调光技术,在保持驱动电流脉冲平均值不变的情况下,调节电流脉冲的幅值来补偿色温漂移.设计了一个基于PWM 和PAM 的LED 驱动器,实验验证了当平均电流相等时,光通量相等,改变峰值电流时,色温改变.因此,提出的一种PWM 和PAM 调制技术在实际调光过程中可以对色温进行补偿,解决了LED 结温变化、老化等问题导致的色温漂移问题.

Light emitting diode (LED) junction temperature variation,aging and other issues will lead to drift color temperature,color and other parameters.Current analog dimming and pulse width modulation (PWM) dimming can not solve this problem.Study found that average current affect flux,and peak currents affect color temperature.Therefore,a PWM and pulse amplitude modulation (PAM) dimming technology is proposed.Without changing the average value of the driving current pulse,we adjust the current pulse amplitude to compensate the color temperature drift.A PWM and PAM LED driver is shown,the experiment verifies that when average current is equal,luminous flux are equal,color temperature change along with peak current.Therefore,a PWM and PAM modulation technique proposed can compensate color temperature drift in actual dimming process,solve the problem of color temperature drift caused by LED junction temperature variation,aging and other problems.