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UC3843: LC Snubber Design for Highest Efficiency?

Omer Faruk
Prodigy 150 points
Part Number: UC3843


Hi,

I have a little and easy question for you. I have designed this schematic with UC3843 and tested it with a prototype. It is working well, 55V 1.2A output. 

Now, I am working for increasing efficiency and decreasing the temperature rise of some components.  

We use RCD snubber for this IC. I have read lots of articles about snubbers and found this method easy and cheap to apply for this circuit. 

My question is that: That's possible to apply this snubber method for this IC and schematic? Is that a really good method for flyback power supplies? Waiting for your reply with your professional experiences.

I have added my design and article about LC snubber. 

Thank you very much

My schematic:

LC Snubber:

WBDesign82.pdf07948040.pdf

  • 0
    TI__Genius 13660 points

    Hello,

    The main purpose  RCD snubber is to reduce switch voltage spikes, but it is inefficient and can't improve the efficiency much  as all energy stored in the leakage inductance is dissipated through a resistor

    Compared with RCD snubber, LCDD snubber consists of an inductor, a capacitor, and two diodes. Although LCDD snubber is known as a nondissipative snubber  is more efficient than the RCD snubber, but by referring some papers, it is not considered to be an efficient snubber because not high portion of energy is recycled.

    Attached paper introduce a novel nondissipative snubber integrated the snubber circuit with the flyback circuit by the addition of a third winding in the transformer. . This snubber is the same as the LCDD snubber with one important difference: the inductor in the LCDD snubber is replaced by a winding that is taken from the transformer. What this winding does is that it provides a way for more of the energy stored in Cclamp to be transferred to the output.

    The new snubber can be used in this application, but I think it costs higher and is more difficult to design.

    A Novel Integrated Nondissipative Snubber for Flyback Converter.pdf

    Regards,

    Teng