The classical clock distribution trees used in the synchronous microprocessor systems in nowadays have several drawbacks such as skew, jitter, frequency limitation, perturbation and disturbance behavioral impact independently of their origin, etc.. These factors, critical for the modern microprocessors, motivate the research of an alternative architecture of the clock generation and distribution system. An example of such alternative architectures is the network of coupled PLLs where the PLLs are geographically distributed on the chip and produce the local clock signals. These local clock signals are then synchronized, in real time, by an exchange of information between the PLLs and by local feedback corrections realized by its controllers. Distributed PLLs network allows overcoming the mentioned limitation encountered for the classical clock distribution system. However, the active nature of this network requires going beyond the scope of usual stand-alone PLL design methods. Indeed, the dynamical aspects of the feedback loops and the transformations of the signal inside this complex system make the design problem extremely difficult to solve. The main issue consists in ensuring certain properties of the global network as well as local properties of each subsystem PLL because those properties may change drastically from independent stand-alone PLL designed with standard tools and methods. Indeed, depending on the network topology, the local properties and global dynamical behavior are not necessarily ensured for the overall network. The main contribution of this PhD thesis is the development of a control law design method for each subsystem (such as PLL) ensuring the desired behavior of the global network. A method for transforming the global design problem to an equivalent local control law design problem is proposed. It is based on the assumption that all subsystems are identical. The relation between the local and global properties is established using advanced Control System Theory tools such as input-output and dissipativity principle. This principle decreases significantly the problem complexity by transforming the design problem into a form that is closed to the design of a stand-alone closed loop system. The proposed method is combined with robust H∞ control and LMI optimization that can be solved efficiently with appropriate algorithms that are well suited for the considered application i.e. the PLLs network synchronization. The proposed approach can be easily generalized to other types of networked system to be controlled.
