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US 8,138,845 B1Granted
Method and apparatus for auto-frequency calibration for multi-band VCO
AssigneeIntegrated Device Technology, Inc.
InventorsYu Zhang, Liang Zhang, Yong Wang, Xin Liu
Life of this patent
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Abstract
A method and apparatus for auto-frequency calibration for multi-band VCO have been disclosed where a VCO is first adjusted to a major frequency band and then adjusted to a sub-band within the major frequency band.
Claims20
An apparatus comprising:
- a voltage controlled oscillator (VCO) having an output (Q) and an inverted output (QB);
- a first bank of switchable capacitors coupled to said Q and connected to a common point (E);
- a second bank of switchable capacitors coupled to said QB and connected to said E;
- a third bank of switchable capacitors coupled to said Q and connected to said E;
- a fourth bank of switchable capacitors coupled to said QB and connected to said E;
- a first set of control signals coupled to said first bank of switchable capacitors and coupled to said second bank of switchable capacitors;
- and
- a second set of control signals coupled to said third bank of switchable capacitors and coupled to said fourth bank of switchable capacitors, wherein said second set of control signals are different than said first set of control signals.
5 more elements
A method comprising:
- forcing a control voltage to approximately one-half a supply voltage;
- counting a feedback clock and generating a first feedback clock count;
- counting a reference clock and generating a first reference clock count;
- comparing said first feedback clock count and said first reference clock count and generating a first control signal;
- adjusting a coarse tuning based on said first control signal;
- counting said feedback clock and generating a second feedback clock count;
- counting said reference clock and generating a second reference clock count;
- comparing said second feedback clock count and said second reference clock count and generating a second control signal;
- adjusting a fine tuning based on said second control signal;
- and
- releasing said control voltage.
8 more elements
A method comprising:
- dividing an operating frequency range of a VCO into qq discreet major frequency bands by selectively coupling a first plurality of capacitors to a first output of said VCO and a common point (E) and by selectively coupling a second plurality of capacitors to a second output of said VCO and said E;
- and
- dividing each of said qq discreet major frequency bands into ss sub-bands by selectively coupling a third plurality of capacitors to said first output of said VCO and said E and by selectively coupling a fourth plurality of capacitors to said second output of said VCO and said E, and wherein said selectively coupling said first plurality of capacitors and said selectively coupling said second plurality of capacitors are independent of said selectively coupling said third plurality of capacitors and said selectively coupling said fourth plurality or capacitors.
Dependencies are inferred from the claim text.