LM4780 PCB for switched power supply

hashwood · 7th March 2011, 11:09 PM

does anyone know where can I find a PCB layout for LM4780 when using a switched power supply ?

TheLaw117 · 8th March 2011, 03:00 AM

Is there any reason why you want an SMPS? I think an unregulated DC supply works just as well if not better under certain conditions.

udailey · 8th March 2011, 03:22 AM

I bought a couple Lambda supplies from Ebay about 3 years ago. They really sounded excellent driving my LM3886 which is of course half of a LM4780.
I am sorry but I dont know of any pcb layout specifically for switched but I also dont think you need a specific layout for switched. I am sure that I didnt need one.
Your switched will need a Plus/Minus/Ground though. Make sure you dont buy one with just Plus and 0V.
Uriah

hashwood · 8th March 2011, 07:11 AM

http://www.national.com/ds/LM/LM4780.pdf
at page 7, Single Supply Application Circuit
isn't this the schematic for an switched supply that has only + and 0v. I'm asking this because I already have a supply with this value, and I plan to use it.

Thanks for your replies

geraldfryjr · 8th March 2011, 07:52 AM

A power supply is a power supply linear or switching.
As long as it meets the power requirments it is supposed to do. jer

pacificblue · 8th March 2011, 06:39 PM

Quote:

Originally Posted by hashwood

a PCB layout for LM4780 when using a switched power supply ?

What do you expect to be different in the amp's layout, when you use a different power supply?

hashwood · 8th March 2011, 06:53 PM

as I said my power supply doesn't have +V, -V, and gnd, as I noticed most of the layouts are using. I only have +V and gnd.
In the datasheet the only schematic that has only +V and gnd is the one on page 7, as I said in my earlier post. Is that schematic OK, can I use it ?

http://www.national.com/ds/LM/LM4780.pdf
at page 7, Single Supply Application Circuit

udailey · 8th March 2011, 08:09 PM

Make sure to read page 18 for single supply operation. Also, since this is how an amp in a car would have to operate I am betting there is an app note about how to implement it and I also bet that in the car audio section you will find folks who have done what you are talking about already.
Uriah

hashwood · 8th March 2011, 09:23 PM

what car

? I want to use it at home...

7th March 2011, 11:09 PM	#1
hashwood diyAudio Member Join Date: Mar 2011	LM4780 PCB for switched power supply does anyone know where can I find a PCB layout for LM4780 when using a switched power supply ?

8th March 2011, 03:22 AM	#3
udailey Passive Aggressive diyAudio Member Join Date: Mar 2008	I bought a couple Lambda supplies from Ebay about 3 years ago. They really sounded excellent driving my LM3886 which is of course half of a LM4780. I am sorry but I dont know of any pcb layout specifically for switched but I also dont think you need a specific layout for switched. I am sure that I didnt need one. Your switched will need a Plus/Minus/Ground though. Make sure you dont buy one with just Plus and 0V. Uriah __________________ You can purchase LDRs anytime to build a standard LDR attenuator or to build my new LDR Attenuator "A Lighter Note". Email me. diyldr@gmail.com

8th March 2011, 08:09 PM	#8
udailey Passive Aggressive diyAudio Member Join Date: Mar 2008	Make sure to read page 18 for single supply operation. Also, since this is how an amp in a car would have to operate I am betting there is an app note about how to implement it and I also bet that in the car audio section you will find folks who have done what you are talking about already. Uriah __________________ You can purchase LDRs anytime to build a standard LDR attenuator or to build my new LDR Attenuator "A Lighter Note". Email me. diyldr@gmail.com

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8th March 2011, 03:00 AM	#2
TheLaw117 diyAudio Member Join Date: Sep 2010	Is there any reason why you want an SMPS? I think an unregulated DC supply works just as well if not better under certain conditions.

8th March 2011, 07:11 AM	#4
hashwood diyAudio Member Join Date: Mar 2011	http://www.national.com/ds/LM/LM4780.pdf at page 7, Single Supply Application Circuit isn't this the schematic for an switched supply that has only + and 0v. I'm asking this because I already have a supply with this value, and I plan to use it. Thanks for your replies

8th March 2011, 07:52 AM	#5
geraldfryjr diyAudio Member Join Date: Feb 2008 Location: Jackson,michigan	A power supply is a power supply linear or switching. As long as it meets the power requirments it is supposed to do. jer

8th March 2011, 06:53 PM	#7
hashwood diyAudio Member Join Date: Mar 2011	as I said my power supply doesn't have +V, -V, and gnd, as I noticed most of the layouts are using. I only have +V and gnd. In the datasheet the only schematic that has only +V and gnd is the one on page 7, as I said in my earlier post. Is that schematic OK, can I use it ? http://www.national.com/ds/LM/LM4780.pdf at page 7, Single Supply Application Circuit

8th March 2011, 09:23 PM	#9
hashwood diyAudio Member Join Date: Mar 2011	what car ? I want to use it at home...

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