A signal according to a phase difference in a first phase-locked loop is transferred to a power supply line as an operation power supply voltage for a first oscillation circuit included in the first phase-locked loop. The potential of the power supply line is supplied to a second oscillation circuit...http://www.google.com/patents/US6570456?utm_source=gb-gplus-sharePatent US6570456 - Clock generator for generating internal clock signal synchronized with reference clock signal
