Other Parts Discussed in Thread: TPS92691
for a new project (LED Driver 12V Input, 28V 0.5A Output) i ordered TPS92691 Eval Board. So far it works fine. The issue is, that on PWM dimming (240Hz), the board is noisy. I know, the ceramic capacitors are producing this hearable noise because of the piezo effect (had this problem also in earlier designs). Also a little bit noise comes from the choke.
Now i would like to ask for further suggestions, to avoid this (any) noise - because more and more customers ask me for an "unhearable" LED-Driver.
What i know to make the noise smaller is:
- using no ceramic caps (using tantal.... or what else ?)
- using decoupled ceramic caps (makes only a few db's)
- using no PWM dimming (how to realize 0%...1% dimming with analog dimming?)
- using big electrolytic capacitors to make circuit voltage stable (lifetime for electrolytic capacitors?)
- using chokes out of compound materials (helps a little bit against choke noise)
Do you have any further suggestions to create an (0% to 100% dimmable), unhearable LED-Driver?
Thanks in advance,