Implementation of ratiometric algorithm to compute partial pressure of Oxygen for a blood oxygen analyser

This paper presents the implementation of ratiometric algorithm based on the Stern-Volmer principle to compute partial pressure of oxygen. The algorithm block sits in a novel bio-signal processor designed for a portable blood oxygen analyzer. The key design constraints of the equation implementation are accuracy (to compete with the traditional blood gas analyzer) and power consumption (to make the whole device portable). All of the arithmetic and logic units have been implemented in a 16-bit floating point format and mapped to 0.35 um CMOS design library using Synopsys Design Analyzer. The addition and multiplication units are implemented using K.C. Chang´s algorithm while the division unit is implemented using Euler´s algorithm.