The AT90PWMxxx chips was designed for dimmable ballasts, and as far as I have heard, this is not a problem in that application. The dithering is used to change the frequency, and not the duty cycle.
The requirement is that you should be able to change the average frequency by 50 Hz at an 80 kHz pulse frequency. The lowest frequency is then 80 kHz / 16 = 5 kHz, and this is much faster than what an eye can detect.
Best Regards Ulf Samuelsson
:)
We may have different expectations of our drive electronics. I'm assuming that either a min pulse width wide enough to avoid not turning on (or off) is enforced in the drive or documented and of course avoided by the PWM generator :)
And of course such expectations are always met.
Robert
It is, however, a high frequency whine generator.
And given a fast minium pulse width of 1uS that is still only 8 bits near the ends. I usually see 2uS or longer minimum widths.
Robert
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