Abstract: A power management apparatus and method are described. The method including monitoring, using a controller, a system bus for a processing demand in a processing system, the processing system comprising the system bus and a system processor, wherein the processing system operates at a first one or more voltages and a first one or more clock frequencies phase-locked to a reference frequency, wherein the controller is a different component than the system processor. The method further including generating a second one or more clock frequencies in response to the processing demand, the second one or more clock frequencies phase-locked to the reference frequency and phase-matched to the first one or more clock frequencies; and switching from the first one or more clock frequencies to the second one or more clock frequencies without halting the processing system.