Dynamic voltage-controlled oscillator calibration and selection
First Claim
1. A method for selecting an active voltage-controlled oscillator from two or more voltage-controlled oscillators comprising:
- establishing a capacitance range, which may include a minimum capacitance and a maximum capacitance, for at least one of a first voltage-controlled oscillator and a second voltage controlled oscillator and recording either a minimum capacitor control value, a maximum capacitor control value, or both for each capacitance range;
determining an overlap region between the first voltage-controlled oscillator and the second voltage controlled oscillator, the overlap defined by overlap capacitor control values corresponding to overlapping frequency range between two voltage controlled oscillators;
receiving a request for a signal at a requested frequency;
determining if the requested frequency is in the overlap region;
if the requested frequency is not in the overlap region, selecting whether to generate the signal at the requested frequency with the first voltage controlled oscillator or the second voltage controlled oscillator and generating the signal at the requested frequency with a selected voltage controlled oscillator;
if the requested frequency is in the overlap region, executing a digital frequency centering (DFC) routine, for either the first voltage controlled oscillator or the second voltage controlled oscillator, which generates DFC routine capacitor control values;
determining if the DFC routine capacitor control values are within an predetermined accepted range for the voltage controlled oscillator on which the DFC routine executed;
if the DFC routine capacitor control values are within a predetermined accepted range for the voltage controlled oscillator on which the DFC routine executed, then selecting the voltage controlled oscillator on which the DFC routine executed to generate the signal at the requested frequency; and
if the DFC routine capacitor control values are not within the predetermined accepted range for the voltage controlled oscillator on which the DFC routine executed, then selecting another voltage controlled oscillator to generate the signal at the requested frequency.
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Accused Products
Abstract
A method and apparatus is disclosed for voltage-controlled oscillator selection in a multi-mode system having multiple voltage-controlled oscillators. Part of oscillator selection is a calibration operation that utilizes maximum and minimum capacitance limits for a voltage-controlled oscillator, which translates to a frequency range, to calculate overlap regions. Overlap regions comprise frequency ranges that overlap such that the overlap region may be generated by two voltage-controlled oscillators with adjacent frequency ranges. One voltage-controlled oscillator selection routine comprises a real time voltage-controlled oscillator calibration and selection routine that executes every time the system requests a new frequency. Another selection routine comprises a start-up routine that executes only at power up or periodically. Another selection routine comprises a successive voltage-controlled oscillator routine that executes every time a frequency is requested by comparing a requested frequency to different frequency thresholds without executing a calibration operation.
23 Citations
29 Claims
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1. A method for selecting an active voltage-controlled oscillator from two or more voltage-controlled oscillators comprising:
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establishing a capacitance range, which may include a minimum capacitance and a maximum capacitance, for at least one of a first voltage-controlled oscillator and a second voltage controlled oscillator and recording either a minimum capacitor control value, a maximum capacitor control value, or both for each capacitance range; determining an overlap region between the first voltage-controlled oscillator and the second voltage controlled oscillator, the overlap defined by overlap capacitor control values corresponding to overlapping frequency range between two voltage controlled oscillators; receiving a request for a signal at a requested frequency; determining if the requested frequency is in the overlap region; if the requested frequency is not in the overlap region, selecting whether to generate the signal at the requested frequency with the first voltage controlled oscillator or the second voltage controlled oscillator and generating the signal at the requested frequency with a selected voltage controlled oscillator; if the requested frequency is in the overlap region, executing a digital frequency centering (DFC) routine, for either the first voltage controlled oscillator or the second voltage controlled oscillator, which generates DFC routine capacitor control values; determining if the DFC routine capacitor control values are within an predetermined accepted range for the voltage controlled oscillator on which the DFC routine executed; if the DFC routine capacitor control values are within a predetermined accepted range for the voltage controlled oscillator on which the DFC routine executed, then selecting the voltage controlled oscillator on which the DFC routine executed to generate the signal at the requested frequency; and if the DFC routine capacitor control values are not within the predetermined accepted range for the voltage controlled oscillator on which the DFC routine executed, then selecting another voltage controlled oscillator to generate the signal at the requested frequency. - View Dependent Claims (2, 3, 4, 5)
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6. A method for selecting a voltage-controlled oscillator from a set of two or more voltage-controlled oscillators comprising:
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initiating a voltage-controlled oscillator selection routine by calculating capacitor control values based at least one minimum capacitance and at least one maximum capacitance for at least one voltage controlled oscillator or recalling from memory at least one capacitor control value for the voltage-controlled oscillator, and calculating at least one threshold frequency for the voltage-controlled oscillator, the threshold frequency related to the capacitor control values that were calculated or recalled from the memory and the threshold frequency defining an overlap region; receiving a signal request for a requested frequency; comparing the requested frequency to the at least one threshold frequency to determine if the requested frequency is in the overlap region; if the requested frequency is not in the overlap region, then generating the requested frequency with a voltage-controlled oscillator selected based on capacitor control values determined during a calibration routine; if the requested frequency is in the overlap region, then performing a digital frequency centering (DFC) routing to generate DFC bit values for the voltage-controlled oscillator; comparing the generated DFC bit values to a predetermined range of DFC bit values for the voltage-controlled oscillator to determine if the generated DFC bit values are within a predetermined range of DFC bit values for the voltage-controlled oscillator; if the generated DFC bit values are within the predetermined range of DFC bit values for the voltage-controlled oscillator, then generating the requested frequency with the voltage-controlled oscillator; and if the generated DFC bit values are not within the predetermined range of DFC bit values for the voltage-controlled oscillator, then generating the requested frequency with a second voltage-controlled oscillator. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A frequency synthesizer having a voltage-controlled oscillator selection routine comprising:
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a synthesizer core including two or more voltage-controlled oscillators, at least one capacitor bank, and at least one switch bank connected to the at least one capacitor bank, the at least one switch bank being responsive to a control signal configured to selectively connect and disconnect the capacitors from a voltage-controlled oscillator to establish a capacitance; a memory storing DFC bit ranges for the two or more voltage-controlled oscillators; and one or more controllers configured to; monitor for a request for a new frequency; responsive to a new frequency request, perform a digital frequency centering (DFC) routine for a first voltage-controlled oscillator to generate first voltage-controlled oscillator DFC bits; comparing the first voltage-controlled oscillator DFC bits to a DFC bit range for the first voltage-controlled oscillator; if the first voltage-controlled oscillator DFC bits are within the range of the DFC bit range for the first voltage-controlled oscillator then establishing the first voltage-controlled oscillator as an active voltage-controlled oscillator to generate the new frequency; and if the first voltage-controlled oscillator DFC bits are not within the range of the DFC bit range for the first voltage-controlled oscillator then repeating the DFC routing on a second voltage-controlled oscillator. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A method for selecting an active voltage-controlled oscillator from two or more voltage-controlled oscillators comprising:
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performing a digital frequency centering routine to create a stored capacitor bank control value range for two or more voltage-controlled oscillators; processing the capacitor bank control value range for the two or more voltage-controlled oscillators to establish control value overlap regions; receiving a request for a signal at a requested frequency; attempting to generate the requested frequency with a first voltage-controlled oscillator by establishing a generated capacitance using a capacitor bank control value; comparing the capacitor bank control value established when attempting to generate the requested frequency with the first voltage-controlled oscillator to determine if the established capacitor bank control value is within the capacitor bank control value range for the first voltage-controlled oscillator; responsive to the comparing, if the established capacitor bank control value is within the capacitor bank control value range for the first voltage-controlled oscillator selecting the first voltage-controlled oscillator to be the active voltage-controlled oscillator; responsive to the comparing, if the established capacitor bank control value is not within the capacitor bank control value range for the first voltage-controlled oscillator then comparing the established capacitor bank control value to a capacitor bank control value range for a second voltage-controlled oscillator; and if the established capacitor bank control value is within a control value overlap region, then repeating the digital frequency centering routine if a time threshold has elapsed since a prior digital frequency centering routine was performed. - View Dependent Claims (21, 22, 23)
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24. A method for selecting an active voltage-controlled oscillator from two or more voltage-controlled oscillators comprising:
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executing a calibration routine to calculate an overlap region and a non-overlap region both of which are defined by one or more capacitor control values for each voltage-controlled oscillator, the capacitor control values corresponding to a range of frequencies at which the voltage-controlled oscillator is capable of operation at specification; receiving a request for a signal at a requested frequency; translating the requested frequency to a requested capacitor control value; evaluating whether the requested frequency is in the overlap region; if the requested frequency is not in an overlap frequency, comparing the requested frequency to a range of frequencies for each voltage-controlled oscillator and establishing a voltage-controlled oscillator as the active voltage-controlled oscillator based on the comparing; and if the requested frequency is in the overlap frequency, executing a calibration routine to generate recalculated capacitor control values for at least one voltage-controlled oscillator and comparing the recalculated capacitor control values to the requested capacitor control value to determine which voltage-controlled oscillator to establish as the active voltage-controlled oscillator. - View Dependent Claims (25, 26, 27, 28, 29)
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Specification