I'm using LM5574 to generate +/-9V from 50-55Vin. The same power input is shared with another SMPS circuit. The LM5574 output looks fine while another SMPS is disabled:
But when another SMPS is enabled a strange ripple appears:
... and this is schematic:
Please let me know what could be done to find a reason why this is happens. Many thanks in advance.