PhD Defence by Nicolai Jerram Dahl

Supervisor

• Professor Michael A.E. Andersen, DTU Electro, Denmark.

Assessment committee:

• Associate Professor, Tiberiu Gabriel Zsurzsan, DTU Electro, Denmark (chair).
• Professor Pavan Kumar Hanumolu, University of Illinois, USA.
• Professor Mats Alaküla, Lund University, Sweden.

Master of the ceremony:

• Associate Professor Ziwei Ouyang, DTU Electro, Denmark.

Abstract:
The research project delves into the exciting world of microelectronics, specifically focusing on time-based control and its potential in integrated power supplies. In classic analog circuits, voltage and current are used to perform mathematical operations. However, by using time instead, time-based circuits circumvent the challenges that arise as transistors become smaller and supply voltages lower. This is achieved by leveraging logic instead of passive components like resistors and capacitors, enabling time-based control with a smaller footprint.
One promising application of time-based control lies in integrated high-frequency power supplies found in everything from servers to smartphones, where efficiency and space-saving are valuable attributes. Although time-based control is still a relatively young research area, its potential is evident. Nevertheless, there remain many unanswered questions to explore.
This research project has three primary research topics: stability of time-based control, exploration of new mathematical operations, and identification of limitations in time-based circuits. Stability analysis investigates how working with time impacts the stability of control loops. New mathematical operations discovered through the project have opened up new classes of time-based systems, and relatively few limitations of time-based control were identified.
This research represents a significant scientific contribution to time-based control and filters. Through a thorough analysis of stability aspects, introducing new mathematical operations, and identifying limitations, this thesis promotes the advancement of time-based circuit design and its possible applications. The results can profoundly impact the efficiency, performance, and size of future integrated switch-mode power supplies and help shape the future of electronics applications.