Can I Increase LED Brightness by Using Pulsed Operation?
Compared to DC operation, it is sometimes possible to significantly increase visible LED brightness by pulsing. There are 3 reasons why pulsing can increase brightness: 1) LEDs have more output at lower temperatures. Low duty factor pulsing can, in some cases, lower the operating temperature of the LED. 2) The human visual system is non-linear. With the right choice of duty factor and pulse rate, perception will correspond more to the peak brightness than to the average brightness. This is especially true at low pulse repetition rates. However, there are a couple of potential problems with using low rep rates: a) Visible LEDs may appear to flicker, especially at frequencies below 30 Hz. b) Flickering sources may be a hazard to epileptics. For more information, see the following sources: : British Epilepsy Association Photosensitivity Info 3) Many LEDs have non-constant luminous efficiency. Luminous efficiency is the ratio of light output per milliamp of input. At very low and very high
