Graduation Year


Document Type




Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Electrical Engineering

Major Professor

Selçuk Köse, Ph.D.

Committee Member

Ismail Uysal, Ph.D.

Committee Member

Nasir Ghani, Ph.D.

Committee Member

Mehran Mozaffari Kermani, Ph.D.

Committee Member

Ulya R. Karpuzcu, Ph.D.


On-chip power delivery network, power efficiency, reliability, stability, voltage regulator


Distributed on-chip voltage regulation where multiple voltage regulators are distributed among different locations of the chip demonstrates advantages as compared to on-chip voltage regulation utilizing a single voltage regulator. Better on-chip voltage noise performance and faster transient response can be realized due to localized voltage regulation. Despite the advantages of distributed on-chip voltage regulation, unbalanced current sharing issue can occur among each voltage regulator, which has been demonstrated to deteriorate power conversion efficiency, stability, and reliability of the power delivery network. An effective balanced current sharing scheme that can be applied to most voltage regulator types is proposed to balance the current sharing. Furthermore, a relatively high on-chip temperature induced by increased power density leads to prominent voltage regulator performance degradations due to aging. The emerging type of digital low-dropout regulator is investigated regarding aging induced transient and steady state performance degradations. Reliability enhancement techniques for digital low-dropout regulators are developed and verified. Such techniques introduce negligible power and area overhead and do not affect the normal operations of digital low-dropout regulators. Reliability enhancement techniques also reduce the area overhead needed to mitigate aging induced performance degradations. Area overhead saving further translates into more space for increased number of distributed on-chip voltage regulators, enabling scalable on-chip voltage regulation.