Viper318HD

[Rahmaa]

 

I have  design Buck  converter with Viper318HD ,With below specification:

Vin:(85 to 265)VAC

Vout=12VDC

Iout=500mA

And i not follow recommended   Commponents   value  which  Are mentioned in Edesign tool,  i use  components which  are availble  with me.

So  i need:

1- Know is this  design  will  be stable  to use it  or not ??

 

 

[Rahmaa]

when  entered  Input voltage with 265VAC  in Edesign  suit   for operating  condition  for Buck converter  with Viper318HD Controller, 

It mentioned in

1- Ton section

" Cycles skip"

2-IC TJ 300C

 Kindly support us to  Know What mean with these  warings   ,and  are   it will effect on Stability of Circuit  if i operate at 220VAC

 

 

[Peter BENSCH]

Welcome @Rahmaa, to the community!

With your specification of 12V, 500mA, we are talking about an output power of 6W, which corresponds to an input power of 8.7W assuming an efficiency of 69%. With these power ratings and the voltage range, you will hardly be able to achieve stable operation, as I have already mentioned several times here in similar projects, e.g. here.

My recommendation: use a transformer and let the VIPER318 work as a flyback, then the design will be considerably simpler, more stable and easier to manage thermally, and you will also have galvanic isolation of the output voltage as a bonus.

Hope that helps?

Regards
/Peter

[Rahmaa]

 @Peter BENSCH ,  I very happy  with your reply ,Thanks  for your support , that's great  reply.

For  my information , kindly inform me what Is  maximum  power to use Viper318HD as buck converter  without any issues(More  stable)??

[Peter BENSCH]

At 12V, you can expect useful output currents around 250mA. At 265V with those 250mA, the VIPER318HD can get up to about 85DEGC, and at 265V with 300mA, it can reach around 115DEGC.

But you could try the VIPER318LD, which runs at 60kHz instead of 132kHz, so the losses are much lower. It does need physically bigger passive components (capacitors, coils), but even at 12V, 500mA and 265Vac, the VIPER318LD only gets (simulated) up to only about 96DEGC.

Regards
/Peter