[sdiy] Function Generator ICs

Steve Lenham lenham at clara.co.uk
Wed Sep 19 15:10:34 CEST 2007


> There are definitely problems with this approach. I'm vaguely keeping  in 
> mind that I'd like to build a polysynth, but the current  consumption of 
> the processor (70-100mA at the speed I'm using) means  I'm going to be 
> using a big power supply if I put 16 voices in it -  300+W just for the 
> oscillators! (How does this compare to synths of  old?)

16 x 100mA = 1.6A
Power = 1.6A x 5V = 8W = not so bad

Running the dsPIC on 3.3V  (if you aren't already) reduces the power 
compared to 5V operation, though the dsPIC30 series won't do full speed at 
3.3V. The dsPIC33 series will.

The other thing is to establish whether you really need to run it flat out. 
The project I'm working on at the moment uses a dsPIC30F5013 on 5V and it 
got toasty warm running at 24.576MHz. I realised I didn't need anything like 
that number of cycles, so halved the clock rate and it runs much cooler.

Cheers,

Steve L.





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