UCC28704: Snubber for secondary diodes

Marzieh Karami

Part Number: UCC28704

Hi,

I am using the output of a flyback for gate circuits and a fan. With a very low frequency (600 Hz), the flyback enters CCM. I have Schottky diodes for the secondary diode. Do I need to add snubbers to the Schottky diode?

over 1 year ago

0 Harish Ramakrishnan5 over 1 year ago

TI__Mastermind 24365 points

Hi Marzieh,

Thank you for reaching out.

Yes, RC snubber on the secondary side is needed. Ideally you want to avoid CCm operation as this controller is inherently intended for DCM operation. Moreover being PSR controller, it better to have RC snubber on secondary as this can help clean up the aux winding waveform for better regulation. Please refer this app note:

https://www.ti.com/lit/an/sluaac5/sluaac5.pdf?ts=1716367533977&ref_url=https%253A%252F%252Fwww.google.com%252F

Regards,

Harish

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UCC28704: Snubber for secondary diodes