LM3886 Current Requirments

Zero Cool · 22nd April 2006, 01:18 PM

I am just starting to get into these chip amps. I have an application where i want to use them. My BMW Stock amplifier uses 10 amplifier channels on 5 chip amps running from the 12V supply, no switcher inside. I am wanting to rebuild something similar using LM3886 amps.

What sort of current is required for these amps under full power @ 4 ohms???

I need to find or build power supply for the project.

Dave

Nordic · 22nd April 2006, 04:28 PM

these chips are rated at about 11A if memory serves correctly...

jaudio · 22nd April 2006, 05:00 PM

If I did the math right,I think it is 5.8A

checkout datesheet page 20

cpemma · 22nd April 2006, 09:22 PM

Your best bet is to get the Overture design spreadsheet and play about. It shows current demands among other things like heatsinks, fb resistors & stuff.

Nordic · 23rd April 2006, 11:21 PM

68W over 4 ohms at 28V...7A
50W over 8 ohms at 35V...4.4A
This however not the max rateing of the chip
MAX output current limit will be between 7 and 11.5A difering from chip to chip

tiltedhalo · 23rd April 2006, 11:35 PM

The current will not be an issue, you will have to make a swtich mode supply to get the voltage up from +12V to something more usable like +/-30VDC. At the 12V from the car battery you will have to have one non-inverted single ended chip and an inverted single ended chip bridged then you will get a 24 volt swing minus loss, for about 18 to 22 watts +or- alittle. You would probably be better of with the orignal TDA chips already built............

22nd April 2006, 01:18 PM	#1
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	LM3886 Current Requirments I am just starting to get into these chip amps. I have an application where i want to use them. My BMW Stock amplifier uses 10 amplifier channels on 5 chip amps running from the 12V supply, no switcher inside. I am wanting to rebuild something similar using LM3886 amps. What sort of current is required for these amps under full power @ 4 ohms??? I need to find or build power supply for the project. Dave

23rd April 2006, 11:35 PM	#6
tiltedhalo diyAudio Member Join Date: Sep 2005 Location: Melbourne Florida	current requirments The current will not be an issue, you will have to make a swtich mode supply to get the voltage up from +12V to something more usable like +/-30VDC. At the 12V from the car battery you will have to have one non-inverted single ended chip and an inverted single ended chip bridged then you will get a 24 volt swing minus loss, for about 18 to 22 watts +or- alittle. You would probably be better of with the orignal TDA chips already built............

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22nd April 2006, 04:28 PM	#2
Nordic diyAudio Member Join Date: Sep 2005	these chips are rated at about 11A if memory serves correctly...

22nd April 2006, 05:00 PM	#3
jaudio diyAudio Member Join Date: Oct 2004	If I did the math right,I think it is 5.8A checkout datesheet page 20

22nd April 2006, 09:22 PM	#4
cpemma diyAudio Member Join Date: Jul 2003 Location: S Yorkshire OK	Your best bet is to get the Overture design spreadsheet and play about. It shows current demands among other things like heatsinks, fb resistors & stuff.

23rd April 2006, 11:21 PM	#5
Nordic diyAudio Member Join Date: Sep 2005	68W over 4 ohms at 28V...7A 50W over 8 ohms at 35V...4.4A This however not the max rateing of the chip MAX output current limit will be between 7 and 11.5A difering from chip to chip

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