CMOS Current Mode Exponential Function Generator Circuit Using Pade Approximation

This paper presents a new exponential function approximation, using Pade approximations. An exponential function generator circuit is designed in CMOS 0.35µm technology using the proposed approximation methodology. Its performance is measured to verify the mathematical analysis using SPICE tool. The results verified that Pade approximation equations can be used in design of EXPFGs and with a judicious choice of the numerator and denominator polynomials, substantial improvement in the dynamic range can be achieved without having to sacrifice circuit complexity.