LM4651/LM4652 replacement

rtarbell · 10th May 2006, 06:24 AM

Has anyone tried using the LM4651 from National Semiconductor and replacing the LM4652 with discrete components? I would think that using discrete MOSFETs should yield a higher power output than 170W (which is what the LM4652 is rated for).

demogorgon · 12th May 2006, 04:53 PM

the distortion and efficency is much to poor compared to other offerings, so i doubt you will find many has put seriouse effort into those chips here.

i know i wouldent bother with them anyways.

-Marius

rtarbell · 15th May 2006, 12:04 AM

I know it is probably not the ideal choice, I was thinking of using it as the basis for a tracking power supply in a class H amplifier (so its distortion and less than perfect quality would not be a major factor).

samborambo · 15th May 2006, 12:47 AM

Hey! I'm building a Class-H too......not much info to go on here except that one Class-H thread. Can anyone point me to a good reference design/schematic?

I've almost finished building the output stages consisting of 8x BPA200 reference design with a few tweaks. The power supply topology I've been looking at is a full wave buck stage (isolating) feeding 8 class-d's to track the voltage for the output stage.

I've come up with a few problems:

Where should I take the error correction from, the input or the output?

If I take it from the output, how do I account for phase shift in the output stage?

Just a note on using D class for voltage following; D's don't like reactive loads so keep capacatince on the output rails to a minimum.

I'd be interested to see what you've come up with so far.

samborambo · 15th May 2006, 12:53 AM

Quote:

Originally posted by samborambo
If I take it from the output, how do I account for phase shift in the output stage?

Should read:

If I take it from the input, how do I account for phase shift in the output stage?

samborambo · 15th May 2006, 01:40 AM

Quote:

Originally posted by rtarbell
Has anyone tried using the LM4651 from National Semiconductor and replacing the LM4652 with discrete components? I would think that using discrete MOSFETs should yield a higher power output than 170W (which is what the LM4652 is rated for).

http://www2.national.com/appinfo/aud..._Lm4651_52.pdf

Read the first two FAQs.

10th May 2006, 06:24 AM	#1
rtarbell diyAudio Member Join Date: Sep 2005	LM4651/LM4652 replacement Has anyone tried using the LM4651 from National Semiconductor and replacing the LM4652 with discrete components? I would think that using discrete MOSFETs should yield a higher power output than 170W (which is what the LM4652 is rated for).

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12th May 2006, 04:53 PM	#2
demogorgon diyAudio Member Join Date: Jul 2004 Location: Behind you.	the distortion and efficency is much to poor compared to other offerings, so i doubt you will find many has put seriouse effort into those chips here. i know i wouldent bother with them anyways. -Marius

15th May 2006, 12:04 AM	#3
rtarbell diyAudio Member Join Date: Sep 2005	I know it is probably not the ideal choice, I was thinking of using it as the basis for a tracking power supply in a class H amplifier (so its distortion and less than perfect quality would not be a major factor).

15th May 2006, 12:47 AM	#4
samborambo diyAudio Member Join Date: Jan 2004 Location: Palmerston North	Hey! I'm building a Class-H too......not much info to go on here except that one Class-H thread. Can anyone point me to a good reference design/schematic? I've almost finished building the output stages consisting of 8x BPA200 reference design with a few tweaks. The power supply topology I've been looking at is a full wave buck stage (isolating) feeding 8 class-d's to track the voltage for the output stage. I've come up with a few problems: Where should I take the error correction from, the input or the output? If I take it from the output, how do I account for phase shift in the output stage? Just a note on using D class for voltage following; D's don't like reactive loads so keep capacatince on the output rails to a minimum. I'd be interested to see what you've come up with so far.

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