Tue Jan 18 23:25:09 EST 2011
I can't remember running into the Translinear Principle (TLP)
before, especially not in school. ( Of course I did run into
log/antilog converters and current mirrors. )
The TLP is a product rule for currents through translinear elements
(TE). To simplify, a TE is a forward biased PN junction, i.e. a diode
or BJT BE junction.
It's quite nifty:
* Construct a loop that goes through TEs traversing each element
forward or backward. A loop needs to contain an equal amount of
TEs traversed in the 2 opposite directions: clockwise (CW) and
counter clockwise (CCW).
* By Kirchoff's law, the sum of all the forward voltages of CC TEs
equals the sum of all the forward voltages of the CCW TEs.
* By the exponential V->I law, this implies that the product of the
forward currents through all the CC TEs equals the product of all
the forward currents through all the CCW TEs.