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US 8,138,846 B2Granted
Precision, temperature stable clock using a frequency-control circuit and a single oscillator
AssigneeSilicon Laboratories Inc.
InventorsManu Seth, David Brubaker, Andrew McCraith, Richard Steven Miller, Mir Bahram Ghaderi
Life of this patent
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Abstract
A frequency-control circuit, which is configured to receive a first signal having a first untuned frequency from a first oscillator, and to alter one or more pulses of the first signal to tune an output frequency of an output clock signal to have an average frequency at the desired target frequency. In some embodiments, the frequency-control circuit receives a signal from a single oscillator to generate a calibrated, precise, and temperature-stable clock.
Claims34
An apparatus, comprising:
- an oscillator to provide a first signal having a first untuned frequency;
- and
- a frequency-control circuit coupled to receive the first signal from the oscillator and to provide an output clock signal having an output frequency, wherein the frequency-control circuit is configured to alter one or more pulses of the first signal to tune the output frequency of the output clock signal to have an average frequency over time at a desired target frequency, the frequency-control circuit comprising:
- a counter configured to receive the first signal with the untuned first frequency in the same form as it is provided by the oscillator, the counter being further configured to count a number of pulses within the first untuned frequency of the first signal as it is received from the oscillator, and
- a pulse-altering circuit coupled to receive the number of pulses from the counter and being configured to alter the one or more pulses of the first signal to tune the output frequency based on the counted number of pulses in the first signal as it is received from the oscillator;
- wherein the frequency-control circuit is configured to receive a measured temperature from a temperature sensor and to alter the one or more pulses of the first signal based on the measured temperature to tune the output frequency of the output clock signal to have the average frequency over time at the desired target frequency over a range of temperatures.
3 more elements
An apparatus, comprising:
- an oscillator to provide a first signal having a first untuned frequency;
- means for counting a number of pulses within the first untuned frequency of the first signal as it is received from the oscillator;
- and
- means for altering the first signal to tune an output frequency of an output clock signal based on the counted number of pulses in the first signal as it is received from the oscillator such that the output frequency of the output clock has an average frequency over time at a desired target frequency;
- wherein the means for altering comprises:
- means for altering the first signal to tune the output frequency to an initial frequency;
- and
- means for altering the first signal to compensate for temperature effects on the apparatus to maintain the output frequency at the average frequency over time at the desired target frequency.
5 more elements
A method, comprising:
- providing an oscillator signal from an untuned oscillator, the oscillator signal having a first untuned frequency;
- counting a number of pulses within the first untuned frequency of the first signal in the same form as it is provided by the oscillator;
- altering one or more pulses of the first signal based on the counted number of pulses within the provided oscillator signal to tune an output frequency of an output clock signal to have an average frequency over time at a desired target frequency;
- and
- further comprising measuring a temperature, and wherein said altering one or more pulses of the provided oscillator signal comprises altering the one or more pulses of the provided oscillator signal to tune the output frequency of the output clock signal to have the average frequency over time at the desired target frequency at the measured temperature.
2 more elements
An apparatus, comprising:
- an oscillator to provide a first signal having a first untuned frequency;
- and
- a frequency-control circuit coupled to receive the first signal from the oscillator and to provide an output clock signal having an output frequency, wherein the frequency-control circuit is configured to alter one or more pulses of the first signal to tune the output frequency of the output clock signal to have an average frequency over time at a desired target frequency, the frequency-control circuit comprising:
- a counter configured to receive the first signal with the untuned first frequency in the same form as it is provided by the oscillator, the counter being further configured to count a number of pulses within the first untuned frequency of the first signal as it is received from the oscillator, and
- a pulse-altering circuit coupled to receive the number of pulses from the counter and being configured to alter the one or more pulses of the first signal to tune the output frequency based on the counted number of pulses in the first signal as it is received from the oscillator;
- and
- a memory coupled to the frequency-control circuit, wherein the memory is configured to store an initial value for tuning the output frequency to an initial frequency for calibration;
- wherein the memory is configured to store a temperature profile of the apparatus.
5 more elements
An apparatus, comprising:
- an oscillator to provide a first signal having a first untuned frequency;
- and
- a frequency-control circuit coupled to receive the first signal from the oscillator and to provide an output clock signal having an output frequency, wherein the frequency-control circuit is configured to alter one or more pulses of the first signal to tune the output frequency of the output clock signal to have an average frequency over time at a desired target frequency, the frequency-control circuit comprising:
- a counter configured to receive the first signal with the untuned first frequency in the same form as it is provided by the oscillator, the counter being further configured to count a number of pulses within the first untuned frequency of the first signal as it is received from the oscillator, and
- a pulse-altering circuit coupled to receive the number of pulses from the counter and being configured to alter the one or more pulses of the first signal to tune the output frequency based on the counted number of pulses in the first signal as it is received from the oscillator;
- a memory to store a temperature profile of the apparatus;
- a temperature sensor to measure a temperature of the apparatus;
- wherein the frequency-control circuit is configured to tune the output frequency of the output clock signal by modifying a threshold number of pulses which is compared against a counted number of pulses of the first signal to tune the output frequency of the output signal to have the average frequency at a desired target frequency over a range of temperatures;
- and
- wherein the oscillator is set such that the untuned frequency of the oscillator signal is always greater than an expected output frequency of the output signal over the entire range of temperatures;
- and wherein the frequency-control circuit is configured to alter the one or more pulses to tune the output frequency of the output signal by removing the one or more pulses based on the comparison of the number of pulses of the provided oscillator signal against the modified threshold value.
8 more elements
An apparatus, comprising:
- an oscillator to provide a first signal having a first untuned frequency;
- and
- a frequency-control circuit coupled to receive the first signal from the oscillator and to provide an output clock signal having an output frequency, wherein the frequency-control circuit is configured to alter one or more pulses of the first signal to tune the output frequency of the output clock signal to have an average frequency over time at a desired target frequency, the frequency-control circuit comprising:
- a counter configured to receive the first signal with the untuned first frequency in the same form as it is provided by the oscillator, the counter being further configured to count a number of pulses within the first untuned frequency of the first signal as it is received from the oscillator, and
- a pulse-altering circuit coupled to receive the number of pulses from the counter and being configured to alter the one or more pulses of the first signal to tune the output frequency based on the counted number of pulses in the first signal as it is received from the oscillator;
- and
- a memory to store a temperature profile of the apparatus;
- and
- wherein the frequency-control circuit is configured to tune the output frequency of the output clock signal to an initial frequency by comparing a pre-programmed threshold value number of pulses against a counted number of pulses of the first signal to tune the output frequency of the output signal to an initial frequency for calibration.
6 more elements
An apparatus, comprising:
- an oscillator to provide a first signal having a first untuned frequency;
- and
- a frequency-control circuit coupled to receive the first signal from the oscillator and to provide an output clock signal having an output frequency, wherein the frequency-control circuit is configured to alter one or more pulses of the first signal to tune the output frequency of the output clock signal to have an average frequency over time at a desired target frequency, the frequency-control circuit comprising:
- a counter configured to receive the first signal with the untuned first frequency in the same form as it is provided by the oscillator, the counter being further configured to count a number of pulses within the first untuned frequency of the first signal as it is received from the oscillator, and
- a pulse-altering circuit coupled to receive the number of pulses from the counter and being configured to alter the one or more pulses of the first signal to tune the output frequency based on the counted number of pulses in the first signal as it is received from the oscillator;
- a memory to store a temperature profile of the apparatus;
- and
- a temperature sensor to measure a temperature of the apparatus;
- wherein the frequency-control circuit is configured to tune the output frequency of the output clock signal by modifying a threshold number of pulses which is compared against a counted number of pulses of the first signal to tune the output frequency of the output signal to have the average frequency at a desired target frequency over a range of temperatures.
6 more elements
A method, comprising:
- providing an oscillator signal from an untuned oscillator, the oscillator signal having a first untuned frequency;
- counting a number of pulses within the first untuned frequency of the first signal in the same form as it is provided by the oscillator;
- and
- altering one or more pulses of the first signal based on the counted number of pulses within the provided oscillator signal to tune an output frequency of an output clock signal to have an average frequency over time at a desired target frequency;
- counting a number of pulses within the provided oscillator signal;
- comparing the counted number of pulses within the provided oscillator signal against a threshold value;
- removing a pulse from the provided oscillator signal when the counted number of pulses within the provided oscillator signal exceeds the threshold value;
- and
- removing an additional pulse when the number of pulses exceeds the threshold value which is dithered from the removal of the pulse.
6 more elements
Dependencies are inferred from the claim text.