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snubber differece between TOP and DPA switch flyback design

Posted by: topswitch_muthu on

Can you explain why ZENER clamp across the FET is uesd in flyback scheme using DPA switch while the same is absent and instead CLAMP (snubber ) circuit is given in all TOP switch FLYBACK SCEME. Any specfic reason?

Regards

 

Comments

Submitted by VCastrellon on 11/18/2013

 

It is a decision of the designer.  Factors like cost, space available, thermal performance, EMI will make the designer to go for TVZ or RC or both. There is not solid rule that says you use RC for specific application or vice versa.   i

Submitted by topswitch_muthu on 11/18/2013

1. I think you have answered for snubber circuit componens variations.

My question is why zener across the "switch " in one case and across the "transformer " in other case.

 

2.Also if you give more light on cost,space,thermal,EMi vs the circuit desIgn for this that will educate more cutomers.

 Regards

 

Submitted by VCastrellon on 11/19/2013

The DPA has a very fast power mosfet at is output.  The  blocking diode in a regular snubber circuit (DRAIN to HVDC BUS), when using with DPA controller,  needs to response very fast when using in this kind of circuits. . If you design a power supply with DPA and want to use regular snubber,  just check your DRAIN voltage do not exceed the maximum DRAIN voltage (of the controller) every time the controller turns OFF.

If you decide an snubber connected from DRAIN to SOURCE then you may have some efficiency degradation. 

Submitted by utkanth on 09/05/2020

Apart from efficiency, cost and space... which scheme is reliable ? across mosfet or snubber clamp between drain and hvdc?

Submitted by PI-Lupin the Third on 09/07/2020

Hi Utkanth,

Thank you for reaching out to us through this forum page. We are more than willing to help you in your concern but if may I request, can you please create a new ticket for this? If you think that this thread is related to your concern, you may simply include the link in your new post.

Looking forward in your new post.

Thank you and Regards,

PI-Lupin the Third