A slicker way to be constantly changing the duty cycle?

[HankMcSpank]

Thanks Henrik...really gracious of you to make the effort - I'm gonna have to read that one a few times, but in the meantime, here's something I can answer...

PS. If "all" you're doing with the PWM output is fading LEDs why do you need it to be inaudible?

.....because ultimately (after I've got on top of all this by playing/dabbling), I intend integrating what I've learnt in some audio circuits (ie using PWM'ed LEDs for visual indicators - flashing/fading, on/off etc) ....the little bit of playing I done with HPWM to date, I've noticed the HPWM carrier can find/bleed its way into the audio signal chain ...hence wanting to put it the HPWM carrier outside the hearing band. I'm quite shocked at the audible clicking too, so I'm trying to dial the clicking out by ramping up HPWM very quickly rather than hard off/on switching.