High performance triple LED driver with digitally controlled analog dimming for reflection pulse oximetry

This contribution describes the development of a prototype that improves standard pulse oximetry to deep tissue penetration. It shows the setup of a control unit operating a high power triple LED driver with a high throughput of electrical power and governing a time table used for proper LED toggeling. To match the depth of light penetration for each used wavelength the possibility of digitally controlled analog dimming has been applied. In order to penetrate human tissue it was important to choose the right wavelengths for the LEDs. For proper data acquisition an active sensor module was designed, using a photodiode and a high resolution ADC. Results show how the prototype’s functionality could be established and first measurements were taken successfully.