How are the ramp values created for a limited FET? (eg in d4v2 with 5A driver). level_calc.py does not seem to give a limited-fet option, […removed]
level_calc.py 5.01 2 149 7135 1 0.3 1740 FET 1 10 3190 —pwm dyn:64:16384:255
you can change 255 for eg 126 (50%) and the PWM2 ramp is what I was looking for. This pwm2 ramp can be used with dynamic pwm, but be sure to set the last value of PWM1 to 255 so the CC driver does not turn off like it does when it goes full-FET.
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Amax = Ch1 + FETmax = Batt_short
Alim = Ch1 + FETlim
FET% = FETlim/FETmax
FET% = (Alim - Ch1) / (Batt_short-Ch1)
so thefreeman posted an interesting calculator last year LED direct drive current calculator
Now I’m guessing the FET limitations are mostly determined through testing…. so anyone know what %FET to use for a d4v2, 5A, osram yellow (CSLNM1.FY)?? Datasheet says they can take 3A max, 4A pulse, but I have now idea how to guess the %FET max pwm to stay safe.