Patent ID: 8258880

Claim:
A frequency generator, comprising: a ring oscillator comprising a number of delay elements coupled in series with one another, wherein an output of a last of the delay elements is coupled to an input of a first of the delay elements and provides an oscillating voltage having an oscillation frequency and a phase; an adaptive voltage supply configured to provide a supply voltage to respective delay elements of the ring oscillator; and a phase comparator element configured to provide a tuning signal based on a difference, if any, between the phase of the oscillating voltage and a reference phase; wherein the adaptive voltage supply is configured to change the supply voltage in response to the tuning signal to limit variation in the oscillation frequency over a predetermined temperature range; wherein the adaptive voltage supply is configured to change the supply voltage inversely with the square root of mobility as a function of temperature in response to the tuning signal to limit variation in the oscillation frequency over a predetermined temperature range.