Highly accurate temperature stable clock based on differential frequency discrimination of oscillators
AssigneeSilicon Laboratories Inc.
InventorsEmmanuel P. Quevy, Manu Seth
Life of this patent
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Abstract
An apparatus and a method for compensating for a mismatch in temperature coefficients of two oscillator frequencies to match a desired frequency ratio between the two oscillator frequencies over a temperature range. In one embodiment of a temperature sensor, first and second oscillators of different temperature characteristics are coupled to a differential frequency discriminator (DFD) circuit. The DFD circuit compensates for the different characteristics in order to match a frequency difference between the first and second frequencies over a temperature range.
Claims6
An apparatus, comprising:
- means for obtaining a desired frequency ratio between a first frequency from a first oscillator and a second frequency from a second oscillator, wherein the first and second oscillators have a mismatch in temperature coefficients;
- means for compensating for the mismatch in temperature coefficients to match the desired frequency ratio over a temperature range.
The apparatus of claim 2, further comprising means for determining a frequency difference between the first and second frequencies as a measure of temperature, wherein the frequency difference is temperature dependent.
An apparatus, comprising:
- a first oscillator to provide a first signal having a first frequency;
- a second oscillator to provide a second signal having a second frequency;
- and
- means for matching a frequency difference between the first and second frequencies over a temperature range.
Dependencies are inferred from the claim text.