My differential input 49830

Phil Olson · 26th March 2008, 07:41 PM

I basically copied their schematic but added a differential input. I decided to do four pairs for possible sub amp use but would start with one pair and add them if power requirements warrant.

Alothough I have the IR FET's there I am considering the Toshiba's mentioned in the 4702 app note.

One thought I had was to drop back to two FET pairs and parallel two boards for the sub. I would just swap the differential pair of one to basically do a bridged design. That's what the BPA-300 design essectially does with seemingly excellent results.

Any suggestions for improvement?

SpittinLLama · 26th March 2008, 09:44 PM

Some of the final values will depend on the PCB layout. The compensation capacitor and gate resistors, for example. Be prepared to adjust them for full stability. The bias may also need to adjust depending on where you want to bias your design. Be sure the drain supply bypassing is close to the FET as possible.

-SL

Phil Olson · 26th March 2008, 10:06 PM

Thanks! I was counting on doing some tweaking. My guess is that going from one FET pair to two or more may also require tweaking.

Mitch Alsup · 27th March 2008, 01:07 AM

Zobel network/filter at the output.

Phil Olson · 28th March 2008, 06:20 AM

Thanks, I forgot to add that.

If that's the worst of it I'll have to pat myself on the back!

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26th March 2008, 09:44 PM	#2
SpittinLLama diyAudio Member Join Date: Apr 2005 Location: In the Wild, Wild West	Some of the final values will depend on the PCB layout. The compensation capacitor and gate resistors, for example. Be prepared to adjust them for full stability. The bias may also need to adjust depending on where you want to bias your design. Be sure the drain supply bypassing is close to the FET as possible. -SL

26th March 2008, 10:06 PM	#3
Phil Olson diyAudio Member Join Date: May 2006	Thanks! I was counting on doing some tweaking. My guess is that going from one FET pair to two or more may also require tweaking.

27th March 2008, 01:07 AM	#4
Mitch Alsup diyAudio Member Join Date: Aug 2007	Zobel network/filter at the output.

28th March 2008, 06:20 AM	#5
Phil Olson diyAudio Member Join Date: May 2006	Thanks, I forgot to add that. If that's the worst of it I'll have to pat myself on the back!

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