Can I connect the output grounds of multiple step-up/step-down voltage regulators safely?
Pololu 24V Step-Up Voltage Regulator U3V50F24 (12v -> 24v) and
Pololu Step-Down Voltage Regulator D15V35F5S3 (12v -> 3.3v)
For that matter, could I connect those output grounds to the input ground as well?
Thanks very much
Yes, you can safely connect the ground connections between multiple voltage regulators. This creates a common ground that is shared between the devices; it is often good to have a common ground between all the components in your system. The grounds for the input and output sides of the U3V50F24 and D15V35F5S3 voltage regulators are already connected through the board, so there is probably not much benefit for connecting them externally.