Patent ID: 7728688

Claim:
A power supply circuit, comprising: a node to receive at least one reference signal; a first voltage regulator to generate a first supply voltage for a first circuit of a phase-locked loop; a second voltage regulator to generate a second supply voltage for a second circuit of the phase-locked loop; and a third voltage regulator to generate a third power supply voltage independently from the first and second supply voltages based on the reference signal, the third supply voltage serving as a supply voltage for driving the second voltage regulator to generate the second supply voltage, wherein the first and second supply voltages are to be independently generated by the first and second voltage regulators based on the at least one reference signal and wherein the first and second supply voltages are to be generated so that a drop in the first supply voltage caused by operation of the first circuit of the phase-locked loop does not substantially change the second supply voltage generated for the second circuit of the phase-locked loop.