LM3886 + output transistor

luixssj3 · 17th February 2009, 12:06 PM

Hi to all!

I would ask you what you think about adding output transistor to a LM3886 to have more power, like the old TDA sch I've added....

What is the pro/cons of the topology?

Thanks to all!

AndrewT · 17th February 2009, 12:59 PM

you would be better using the chips that National has released to do just that.
See threads on lme498x0

luixssj3 · 18th February 2009, 07:34 PM

Many thanks!

Very interesting IC!!! But a little difficult to find in Italy

Minion · 18th February 2009, 10:18 PM

You can also make an amp with discrete output stage from a TDA7293 100w DMOS chip , if you need more than 100w...

check the TDA7293 data sheet, there is also a PCB design in the datasheet....

Cheers

djoffe · 15th March 2009, 08:46 PM

thanks for the info about the lme49811, etc....I'll have to play around with those.

If you're looking for more current drive, you could do something like this. Please note...it's a concept drawing...some components are omitted...the basic idea is that at low output currents, most output comes from the national part, as output current demand increases, the output transistors kick in above about 0.4 Amps. You'll need to experiment some for stability considerations...just consider this as a suggested starting point...

star882 · 16th March 2009, 03:24 AM

It would be very impractical to use analog for high powers. The thermal dissipation would become a big problem (watercooling needed) and the power supply would be very expensive. A pure or hybrid digital would be a better solution.
TI has a pure digital chipset (TAS5261 power stage + TAS55xx digital driver) good for over 200W. Use a discrete power stage and it can be even higher. Only small heatsinks would be needed

16th March 2009, 03:24 AM	#6
star882 diyAudio Member Join Date: Mar 2007	It would be very impractical to use analog for high powers. The thermal dissipation would become a big problem (watercooling needed) and the power supply would be very expensive. A pure or hybrid digital would be a better solution. TI has a pure digital chipset (TAS5261 power stage + TAS55xx digital driver) good for over 200W. Use a discrete power stage and it can be even higher. Only small heatsinks would be needed __________________ "Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
which output transistor?	solid	Solid State	1	2nd May 2009 10:23 AM
Radio output before transistor amp	Calamaro	Analogue Source	0	10th October 2008 01:00 PM
Can bias transistor mount on top(body) of output transistor??	Leolabs	Solid State	23	16th February 2008 12:35 AM
Output transistor	jboo8706	Class D	2	21st August 2006 11:30 PM
TV Horzontal Output Transistor for output stage..?	ronybc	Solid State	46	10th October 2005 02:26 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

17th February 2009, 12:59 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	you would be better using the chips that National has released to do just that. See threads on lme498x0

18th February 2009, 07:34 PM	#3
luixssj3 diyAudio Member Join Date: Aug 2004 Location: sulmona	Many thanks! Very interesting IC!!! But a little difficult to find in Italy

18th February 2009, 10:18 PM	#4
Minion diyAudio Member Join Date: May 2006	You can also make an amp with discrete output stage from a TDA7293 100w DMOS chip , if you need more than 100w... check the TDA7293 data sheet, there is also a PCB design in the datasheet.... Cheers