Lme49830

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Segran

Member
Joined 2008
Pin3 to which GND???!!!

I have been off (licking my wounds...) and modified my own PCB w.r.t. Pin3, moving it to Clean GND as per Per-Anders advice:
The datasheet signal ground for the pin 3 and I also think this is right
Click to expand...

Andrew is of a different opinon:
Pin3 should not be connected to the clean ground
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To further add to my confusion:
In Fig. 3 of AN-1850 shows Pin3 connected to PWR GND.
In Fig. 4 of the datasheet Pin 3 is connected to Clean GND :dodgy:

I am still confused, but not even to a higher level.... :confused:

I can't substantiate the difference when measuring on the two different connections right now since I blew up my Asus Xonar Essence soundcard, and can't measure anywhere near what my amp produces with the MB soundcard circuit.

My first question is: Where to connect pin3? Clean or PWR GND, or is it of less/no importance? :scratch:

My second question may be a bit more subtile:
Pin 8 (Osense) - does it make a difference if it shares the track coming from the output with the NFB (pre NFB resistor)? :scratch:
 
S

Segran

Member
Joined 2008
AN-1850

Difficult to follow them!
Click to expand...

Yes, tell me about it....:(

I am still bewildered by this question, having tried pin3 connected to both I still don't know which is (more) correct..:apathic:

Concerning the decoupling capacitors being connected to clean ground - this is against everything I thought was common knowledge, so I follow my religion and stubbbornly connect them to power ground... :devilr:

It would be nice if anyone with the appropriate measuring equipment can quantify the difference.
 
bobodioulasso

bobodioulasso

Member
Joined 2008
Finally i think that in the doubt , it is a better choice to connect pin 3 to input/clean ground: little current will flow there, so, the risk to pollute this ground is small. In AN, they even permit themselves to use this ground for decoupling the LME supplies for the same reason i suppose. At the opposite, if you connect pin 3 to dirty ground, the risk to pollute the input stage ground with high current is big.
Forgive my english
 
M

morsenuc

Member
Joined 2009
lme49830

I have finished a four-channel version of the lme49830/IRFP240/9240 with a "Green" feature. Exploiting the dual-voltage transformers available, I can switch between 22 volts and 44 on the rails with a constant 8 volt oversupply for the chip's power. I added an optoisolator with a 100K resistor in series and apply that to the base and collector of the Vbe multiplier. In the Green setting, the amp idles at 40 mA with the 22 volt rails, i.e. less than two watts per unit. In the hot mode it runs at 200 mA and 44 volts or the rails, for quite a bit more standby power. The idea here is to have the option for no-holds-barred performance, but leave the amp on for background music most of the time. The green mode is enough power and low enough distortion for all but the most demanding applications, given efficient speakers.
 
N

naturey

Member
Joined 2010
Segran said:
Hi Spittin Llama and other pro's, I have a LME49830/MOSFET PCB layout (sorry nickarsow, it's not SMD...) to which I would like to get some feed-back. This is supposed to be the final version, I have made improvements to the signal ground and feed-back loop compared to the previous prototypes.

Thanks in advance!
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HI,Segrnan,
I am very glad to find your design, I feel very good. Could you please send me your design documents(May be Gerber files)? My mailbox naturey@163.com.

THANKS,
Naturey
 
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naturey

Member
Joined 2010
AndrewT said:
Is this another Member about to go commercial with someone else's IP?
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I know, I'm using it myself. If there are difficulties, then I will design their own. By the way, your design is also very good. I saw someone using a IRFP240 and two IRFP9240 in the Chinese Forum (HIFI?????_????hifi?????diy??????) to make the power amplifier, the voltage is +100V and -100V, I also want to learn to make a power amplifier.
 
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