Potențiometre digitale cu performanțe îmbunătățite cu aplicații în sistemele audio-video / Digital potentiometers with improved performances with applications in audio-video systems

The PhD thesis covers digital potentiometers field used in audio-video systems for volume, brightness and contrast adjustments. This thesis has three main sections. In the first one, a general description of digital potentiometers is given. In the second one the components of a digital potentiometer are analyzed through simulations. Here, the functionality of the digital adjustment control part and the performances of several potentiometer architectures and switches (very important elements of digital potentiometers) selected from literature are presented. The third section concentrates on two new potentiometer architectures having improved linearity and two new switches versions whose purpose is to eliminate actual limitations of potentiometers. One of the new proposed potentiometer architectures and two most performant configurations presented in the second part were used in the silicon implementation of four digital potentiometers. The experimental, simulated, and theoretical (based on a proposed mathematical model) results confirm the new potentiometer architecture superiority. Moreover, the measured results show the importance of the layout and fabrication technology in designing high performance digital potentiometers. As it concerns the new switches versions, their functionality and characteristics were proven by simulations, but also by measurements done on the silicon implemented test structure for one of the two variants.