Hi,
I've attached the 2013 User's Guide for power products. Starting on page 53 you will find a selection of PWM controllers. many of these teh frequency can be varied according to external criteria.
As an example if you use a UC3842 it is a simple…
Gary,
Most any of our power controllers with dual output capability will provide the control. See attached document starting at page 50 with the dual output controllers on page 53 and 54 and choose what features you want.
Regards,
John
