A switched voltage regulator provides improved regulation at a lower clock
rate/sampling frequency (e.g. several orders of magnitude lower than
would be required for comparable regulation) while using a low resolution
digital pulse width modulator such that limit cycle oscillations occur
(and thus of low cost and complexity and small size) by limiting the
amplitude of limit cycle oscillations which therefore need not be avoided
by more complex arrangements which are not commercially feasible.
Limiting of amplitude of limit cycle oscillations is achieved by adding
essentially a digitized ripple voltage signal corresponding to the
difference between the output of the voltage regulator and an average
output of the voltage regulator as an input to the digital pulse width
modulator. Performance of this arrangement may be enhanced by adding a
ramp signal to the digitized ripple voltage signal and even further
enhanced by limiting the ramp signal to a range which corresponds to
steady state operation but not transients.