[sdiy] Patchell's Boggling 13700 Expo Converter Thing???

[ASSI]

On Sunday 22 June 2003 19:08, Ian Fritz wrote:
> > The linearized OTA
> > must be driven by a diffrential current source with a stable common
> > mode current in order to operate correctly.
>
> Yes, this is well known, and we understand it.  But how do you
> actually  implement the current-source driver? 

Two current mirrors (npn and pnp) are enough to do this, just in the 
same way that the output current of the OTA is mirrored out. A few more 
transistors and you have a transconductance multiplier...


Achim.
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