I have designed a circuit using the LT3942 to drive several differents LEDs.
When I drive a Amber LED with Vf = 2.1V, I got a current peak of 570mA for 10µs then goes to 220mA.
Following curve shows signals when PWM signal rise:
Blue curve = V ISMON with Rshunt = 0.33o:
Red curve = PVOUT
Datasheet says that LT3942 is 0V to 36V Output Voltage Range.
My observation is that if the output voltage is less than 3V, the driver may not works properly with PWM command. In my case, the LED may be damaged because of over current (I max of the LED is 350mA).
What is the solution to avoid over current on a 2.1V LED ?
Thanks in advance for help.