During the last decade the technology's evolution of modern microprocessors has brought better computing performance; but now energy efficiency is a new goal for general-purpose computing architecture. This target is now one of the most important technology drivers from the mobile to networking applications. Energy management has become a key issue for server and data center operation, considering all energy-related costs. The server architecture research is working focusing on energy proportional machines that would ideally consume no power when idle, and gradually more power as the computation level increase. This performance can be supported by a server architecture and power management architecture that guarantees a high efficiency with a high range of load. Moreover faster processors require high performance during the transient. In this paper a Constant on time digital control loop will be described that has a high performance transient response, easily implements a fast phase shedding technique and has an efficient light load working condition. The controller has been implemented in 0.16um lithography together with a DPWM with 195ps resolution and 40Ms/s ADC 7 bits pipeline converter. Experimental results of a 100 A, 1.8 V multiphase buck converter with a constant on-time controller are provided to show the effectiveness of the discussed system.
