Apparatus and method for frequency tuning an LC oscillator in a integrated clock circuit

摘要

A method and system in an integrated circuit for frequency tuning oscillator circuits. An oscillator circuit within an integrated circuit is formed on a substrate such that the oscillator circuit is coupled to an inductor component. The inductor component includes a first inductor positioned parallel to a second inductor such that a total effective inductance is associated with the first and second inductors. The first inductor is formed from a first spiral coil layer which is coupled to a second spiral coil layer on the substrate. The second inductor is formed of a single spiral coil layer on the substrate, wherein the single spiral coil layer provides an inductive feedback signal to the oscillator circuit when electrical current flows through the single spiral coil layer in response to current flowing through the first spiral coil layer and the second spiral coil layer. The feedback signal can be adjusted such that a change in a phase associated with the feedback signal results in an alteration of the total effective inductance, which in turn shifts a center frequency associated with the oscillator circuit thereby promoting frequency tuning of the oscillator circuit over a wide tuning range. In addition, a capacitor component can be connected to the oscillator circuit such that the capacitor component includes two series connected capacitors which have an associated effective capacitance. A change in the effective capacitance also results in a shift in the center frequency.