Technical white paper from Renesas on using digital control loop to achieve more stable power supply. Link here (PDF)
New trends and changing requirements in the power management industry influence how we design power supplies. Some, like the need for telemetry and system information, are more recent due to advancements in technology. Others, like the demand for smaller solutions, higher levels of integration, faster transient response and high switching frequencies, have been around for decades. But throughout the entire history of power system design there has been one requirement that has been constant: the need for a stable power supply.
This article details the common problems plaguing analog voltage mode control loops and shows how a digital control loop is able to provide bandwidth that was previously dismissed as unobtainable. By walking through the variables associated with stability and comparing it to an analog control system, it can be seen that a digital control loop is able to achieve faster transient response and improved performance while maintaining a stable loop.