Integrated design has become a very attractive choice for modern power electronic systems. One way to introduce modularity to integrated designs is to utilize intelligent power electronics building blocks as a base for power electronics systems. The main reason for moving toward a building-block-based design is that the traditional centralized control structure does not provide much flexibility and reusability. A building-block-based design needs a distributed control scheme that sets new challenges to system design. Distributed control of building blocks requires a deterministic, real-time communication scheme and accurate synchronization. The synchronization becomes an issue especially with ring-based control topologies. In this paper, a flexible time-stamping-based synchronization scheme for a cascaded ring communication topology is proposed. Further, a communication scheme suitable for building-block-based designs is presented. The achieved synchronization accuracy is analyzed in relation to a parallel connection of power semiconductors.