Linear current source

Christopher_List at Sonymusic.Com Christopher_List at Sonymusic.Com
Thu Oct 24 23:09:17 CEST 1996






  Magnus wrote;
  > In the ASM-1 there is a op-amp and two diodes that drives an CA3080 with =
  > linear control. I haven't put that schematic on the web.... yet!

  ...and Gene wrote;
  > The V- pin on the 3080 is driven by the op-amp's output.
  > This is about the simplest way to apply an accurate linear OTA control
  that I've seen.
  > Conveniently, the op-amp's (-) input is a summing node for positive
  control voltages.
  > The OTA output is a current so it needs an I-to-V converter (another
  op-amp);

  ...That's right, I had forgotten about this. One of the timbre modulators
  I built uses this method for voltage controlled x-fading. This is a good
  method, and I will keep it closer to the front of my mind for future
  use...

  Unfortunately, it doesn't work so well for 13600's! I guess I could just
  use two 3080's...

  Thanks guys
  - Chris





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