an led driver circuit and a method prevent led turn - off flash when input power is lost to the driver circuit . the driver circuit includes a dc - dc converter that provides an led drive voltage to an led load . a voltage drop sensing circuit detects the loss of input power and discharges a filter capacitor that provides operating power to a controller in a dc - dc converter . the controller turns off to halt the operation of the dc - dc converter before the voltage provided to the led load decreases to a turn - off threshold of the led load . the dc - dc converter cannot recharge a load capacitor across the led load . thus , once the leds in the led load turn off , the leds remain off until the input power is restored .