LM4780 paralell pcb

[sasmit]

This is my attempt at making a PA100 using LM4780 comments welcome..

 

[kuldeepsingh]

ya, nice layout. .

 

[sasmit]

This the psu board design...any issues with this layout ?

 

[sasmit]

This is the schematic for the PSU, I have taken some of the ideas from the national application note for audio amp psu.

 

[Adrculda]

Nice layouts, what software are you using ???

 

[sasmit]

It's Eagle..guess eveyone in the diy world uses it..

 

[Adrculda]

It's Eagle..guess eveyone in the diy world uses it..

almost..
going to look to download it now

 

[sasmit]

ya download's pretty straight forward...but the freeware version has limited board size, plus some manipulations on the board like mirroring etc don't work if the component moves outside the bounds of the freeware size..even if temporarily

 

[GeriatricSod]

So where can one download Eagle?

Thanks for being patient - I'm a newbie and I just found this site...🙂

 

[jman 31]

Right HERE

 

[Adrculda]

Right HERE

Or Here 😉

 

[jman 31]

Or Here 😉

Haha, yeah. IsoHunt is my favorite stomping grounds.

 

[Sebastiaan]

This is my attempt at making a PA100 using LM4780 comments welcome..

Dear Sasmit,

Nice artwork. However I would not let the positive and negative supply lines form a circle. Try to keep them together till the chip, and on the last point go left and right. Right now the sensitive feedback resistors are choked by the magnetic field of both supply lines. Not to nitpick, but if you take care of that you can really improve the circuit.

With kind regards,
Bas

 

[Adrculda]

I would replace those bleeder resistors as well with LED's if you want something to discharge those caps...
The only way resistors would be useful is if you set them up in a RCL to filter unwated noise from mains.
Otherwise seems like a pretty clean circuit.

Hope your using one board per side as there isn't much capacitance on that sucker...

 

[sasmit]

Dear Sasmit,

Nice artwork. However I would not let the positive and negative supply lines form a circle. Try to keep them together till the chip, and on the last point go left and right. Right now the sensitive feedback resistors are choked by the magnetic field of both supply lines. Not to nitpick, but if you take care of that you can really improve the circuit.

With kind regards,
Bas

LM 4780 is a bit tricky to work with because of two channels crammed into such a tight space, but let me have a go at it.

 

[Sebastiaan]

LM 4780 is a bit tricky to work with because of two channels crammed into such a tight space, but let me have a go at it.

Yeps, It ain't going to be easy 😀

With kind regards,
Bas

 

[AndrewT]

two channels trying to dissipate heat into one shared heatsink interface is also a big challenge.

 

[sasmit]

two channels trying to dissipate heat into one shared heatsink interface is also a big challenge.

ya that sure is a big problem, although on paper you coud churn out a lot of power from these things but practically it's very limited !

 

[sasmit]

Now the power rails are together, replaced the zobel resistor footprint to fit a 5W type .

 

[Sebastiaan]

Now the power rails are together, replaced the zobel resistor footprint to fit a 5W type .

Dear Sasmit,

It is an good improvement, and I like the power rails like this. I find the long feedback trace between R4 and R7 a little bit sad. This could be solved by using a 4 layer PCB.

In big lines I like your PCB. the power stuff on the right and the line stuff on the left.

With kind regards,
Bas