[sdiy] Temperature compensation with a MOSFET

[rjelliffe at allette.com.au]

Interesting Nokia patent: they find PTATs expensive too!

http://www.wipo.int/pctdb/en/wo.jsp?IA=FI1998000736&DISPLAY=DOCS

 "The invention relates to a method for temperature compensation in an
electric circuit. In order to get rid of costly manufacturing processes
and external components, a PTAT resistor is replaced by a series
connection of two resistive elements (Rx, 31), the first of said elements
(Rx) having essentially constant resistance regardless of the
temperature, and the second element (31) having a resistance which is
non-linearly dependent on the temperature. The resistance value of the
first element is selected so that an approximation of the resistance of
said series connection is directly proportional to the temperature"

The patent suggests a MOSFET with a 1V gate source and suitable resistor
can do the job. I wonder whether it is good enough for synths?

Cheers
Rick Jelliffe