TIDUF77 June 2024 MSPM0G1507
A non-isolated UCC28911-based flyback supply provides auxiliary power supply for this reference design to delivery up to 100mA for 15VDC and 300mA for 5V. 5V is used to create 3.3V for microcontroller and related circuit by an additional TLV74033 regulator. Figure 2-4 shows the UCC28911 flyback power supply circuit.
Place R40, C35, R37, R41 and C38 closely to UCC28911, C38 is not needed normally but can be needed if R37 and R41 is too far away from UCC28911.