[onerng talk] Possible magnetic vulnerability

[Gerd v. Egidy]

> Your noise source is driven by a higher voltage generated by a switching
> supply.  If the inductor in that supply is anything but air-core, it is
> potentially vulnerable to saturation by a constant or very-low-frequency
> -magnetic- field.  Your copper shielding will have a very limited effect on
> such a field.

A solution would be to allow the controller to read out the actual voltage 
after the stepup via a voltage divider over an adc input pin. 

Probably a bigger output cap for the stepup would help to reduce the influence 
effects for the short time till you detect them on the adc.
 
Kind regards,

Gerd