US Patent 7546332 Apparatus and methods for implementation of mathematical functions

Apparatus and methods for implementation of mathematical functions apparatus providing both speed and accuracy. Disclosed are specific circuits and methods of operation thereof that may be used for the purpose of implementing an exponential function, a squaring function, and a cubic function, using the same basic circuit. By applying a desired weighting function on a current source, an output current provides a value that corresponds exactly to the desired mathematical functions at discrete points, and closely tracks values in between the discrete points. The precision is defined by the selection of a voltage reference for the circuit. Various embodiments are disclosed, as well as embodiments implementing other exemplary functions.