A multi-phase regulator that provides a smooth transition between DCM and
CCM by employing partially synchronous rectification in which a duty
cycle of a synchronous switch enable signal is gradually increased to
100%. The regulator includes a separate inductor, high-side switch, and
synchronous switch for each phase. The high-side switches are controlled
based on a separate PWM signal for each phase. Each PWM signal is
provided by pulse width modulating the error signal, with each of the PWM
signals having a different phase. During the partially synchronous
rectification, the synchronous switch turns on when the high-side switch
is off and the synchronous switch enable signal is asserted, and the
synchronous switch is off otherwise. The synchronous switch enable signal
has a frequency relative to the frequency of each of the pulse width
modulation output signal such that good current sharing among the
inductors of each phase is achieved.