Development of a microcontroller controlled transistor based current source for pulse oximeter devices

摘要

In pulse oximeter devices, the most important issue is the generation of appropriate light intensity by the light source according to the color and the composition of the target tissue. For this purpose, these devices are equipped with dedicated driver circuits that transfer different levels of DC current levels to the LEDs acting as the light sources. The current level is typically ranging from 5mA to 20mA and automatically adjusted so as to increase gradually. In this study, three different transistor based and microcontroller-controlled DC current sources for use in pulse oximeter devices have been designed, simulation and practical implementations have been performed and results have been analyzed.