DRIVE METHOD AND DRIVE SYSTEM FOR IMPROVING LUMINOUS EFFICACY OF LIGHT EMITTING DIODE

摘要

A drive method and a drive system for improving the luminous efficacy of light emitting diode (LED) are provided. The method includes: switching the direct current supplied to the LED periodically between a first current level I H and a second current level I L, the first current level I H being higher than the second current level I L, the value of the second current level I L being kept on at least zero in order to produce a direct current bias; through reducing the difference value between the first current level I H and the second current level I L and regulating the duty ratio of the first current level I H correspondingly, the average current being kept on a given current value . The drive method and the drive system can improve the luminous efficacy of LED effectively.