Clock ratio controller for dynamic voltage and frequency scaled digital systems, and applications thereof

A tangible computer readable storage medium comprising a digital system embodied in software, the digital system comprising:

• a first digital circuit that operates at a first rate determined by a first clock signal;
• a second digital circuit, coupled to the first digital circuit by a bus, that operates at a second rate determined by a second clock signal;
• and
• a clock ratio controller that adjusts a frequency of at least one of the first clock signal and the second clock signal in response to a power management signal without causing a loss of synchronization between the first digital circuit and the second digital circuit.

A method of controlling clocking frequencies in a digital system, wherein the digital system includes at least a first digital circuit and a second digital circuit coupled together by a bus, the bus being used to facilitate communication between the first digital circuit and the second digital circuit, the method comprising:

• (1) generating a first clock signal that is provided to the first digital circuit and a second clock signal that is provided to the second digital circuit;
• (2) determining an alignment between the first clock signal and the second clock signal;
• and
• (3) adjusting a frequency of the first clock signal during the alignment.