A cascadable power regulator including a programmable delay unit and PWM
control logic. The programmable delay unit initiates a delay period in
response to a digital input signal and asserts a digital output signal
upon expiration of the delay period. The PWM control logic controls a PWM
cycle in response to the digital input signal and in response to an
output control condition. The cascadable regulator uses digital signals
to communicate between channels. Digital signals are not prone to the
same kind of signal degradation or noise susceptibility as analog
signals. Thus, the number of phases is not limited, the physical
separation between the regulators is not limited, and the switching
frequency is not as limited. There is no clock signal from a separate
controller so that the controller is a relatively simple, low-cost
device. Since there is no clock, a unique self-oscillating system is
achieved using the cascadable regulator.