Step-up Converter for White LEDs

White LEDs are increasingly used for lighting applications in battery-powered equipment. To cope with the effects of a fluctuating supply voltage, a constant-current source is a must.There are now countless applications where white LEDs (light emitting diodes) are used as background) light sources. As examples we could mention LCD or keyboard backlighting. Alternatively, white LEDs have advantages in bicycle lights and energy-friendly pocket flashlights.