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From: mk59200@metso.tut.fi (Kolkka Markku Olavi)
Newsgroups: sci.electronics
Subject: Re: High Power Digital/Analog converters
Message-ID: <1990Jun26.093222.13434@funet.fi>
Date: 26 Jun 90 09:32:22 GMT
References: <3364.26832a9d@ccvax.ucd.ie> <3800@memqa.uucp>
Sender: news@funet.fi (#News )
Reply-To: mk59200@metso.tut.fi (Kolkka Markku Olavi)
Organization: Tampere University of Technology, Finland
Lines: 26

In article <3800@memqa.uucp> r91400@memqa.uucp (Michael C. Grant) writes:
>In article <3364.26832a9d@ccvax.ucd.ie>, b_haughey@ccvax.ucd.ie (Brian J Haughey) writes:
>> I'm looking for information on D/A converters that could directly supply 
>> an output to a speaker from low to high volume. (Is such a thing possible ?)
>
>For example, supplying high power output from a D/A converter would require
>high powered semiconductor circuitry, and about the only high-power 
>semiconductors available today are for power amplifiers and special
>solid-state power-distribution fault-detection circuitry.  As for a 
>monolithic circuit like a D/A converter, you could try building one
>from discrete components, but I wouldn't recommend it.

Power MOSFETs are fairly common these days and I think you could
make a high power D/A using them and the new 1-bit (Bitstream, MASH or
whatever) conversion technologies.  Driving the FETs in high speeds needs
some thought, but otherwise it shouldn't be too difficult, if you can
get a standard chip that converts the 16-bit data into PWM.

>Secondly, volume control is also impractical in a D/A converter.

There are several consumer systems around with digital volume control,
it's really not that difficult (you do it _before_, not in the D/A).

--
	Markku Kolkka
	mk59200@tut.fi