  With an increasing number of power-states, finer- grained power management
and larger dynamic ranges of digital circuits, the integration of compact,
scalable linear-regulators embedded deep within logic blocks has become
important. While analog linear-regulators have traditionally been used in
digital ICs, the need for digitally implementable designs that can be
synthesized and embedded in digital functional units for ultra fine- grained
power management has emerged. This paper presents the circuit design and
control models of an all-digital, discrete-time linear regulator and explores
the parametric design space for transient response time and loop stability.
