I see this on my output..
At first glance you would think this is likely normal.. until you look at the time scales... The spikes actually happen at around 166Hz...
I basically took the example circuit, and EVM circuit and rebuilt it (not sure if I have this issues on the EVM, will check tomorrow)
What looks like the output ripple, actually isn't... There seems to be a really slow oscillation going on and huge spikes at 166Hz, but why ?
The IC runs at about 340KHz, I can see the ripple + noise, ripple is <10mV, noise about 20mV. But this isn't what I am displaying in my images..
I am using a 22uH inductor, I changed for 10uH, the pulses went to about 180Hz then..
If I add a low ESR 4,700uF capacitor on the output, all seems fine then.. but the circuit should be happy with 44uF under 1amp load anyway.. in fact 22uF is no different than 44uF (ceramics)
I have had issues with my scope picking up noise from LED lighting in my workshop, but I haven't yet been able to find a cause for these spikes. In fact most noise is still on the scope without probes connected to anything (but mostly <20mV) The spikes only appear when probes are connected to my PSU board.. So much be something circuit related causing this... ?
