The two most likely causes of flicker is related to an improper selection of the driver due to output voltage range, or a misapplication of the line voltage dimmer. Verify that the forward voltage of the LED is within the rated output voltage range of the driver. Many dimmers require a minimum load that is greater than 1 fixture. Verify that the installation meets the minimum power rating of the dimmer. Please refer to Roal Application Note 1 for detailed information on dimming and Application Note 2 for information on the selection of the driver.