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US 7,548,124 B2Granted
System and method for self calibrating voltage-controlled oscillator
AssigneeSamsung Electronics Co., Ltd.
InventorsHyun Soo Chae, Jung Eun Lee, Chun Deok Suh, Hoon Tae Kim
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Abstract
A system and a method for self calibrating a voltage-controlled oscillator (VCO). In the system, a mode controller generates a control signal for each of an automatic band selection mode, an automatic gain tuning mode, and a phase-locking mode, from a frequency comparison result between a reference clock signal and a divided clock signal which is generated by dividing a frequency of an oscillation signal, and thereby controls the VCO, so that the VCO may generate the oscillation signal which is automatically phase-locked in a target frequency with an optimal state.
Claims20
A system for generating an oscillation signal, the system comprising:
- a voltage-controlled oscillator (VCO) which generates first to third oscillation signals according to first to third control signals of an automatic band selection mode, an automatic gain tuning mode, and a phase-locking mode, respectively, with respect to the VCO;
- and
- a mode controller which generates:
- the first control signal from a first frequency comparison result between a reference signal and a first feedback signal generated by dividing a frequency of an initial oscillation signal of the VCO by a first number, to control the VCO to generate the first oscillation signal in the automatic band selection mode;
- the second control signal from a second frequency comparison result between the reference signal and a second feedback signal generated by dividing a frequency of the first oscillation signal by a second number, to control the VCO to generate the second oscillation signal in the automatic gain tuning mode;
- and
- the third control signal to control the VCO to generate the third oscillation signal which is phase-locked in the phase-locking mode,
- wherein the mode controller comprises:
- a first switch which provides signs of the first or second frequency comparison result to a first or second path, respectively, according to a mode selection signal selecting one of the automatic band selection mode, the automatic gain tuning mode and the phase-locking mode;
- a second switch which outputs one of a first voltage, a second voltage or an oscillation-controlled voltage to the VCO, respectively, according to the mode selection signal;
- a band controller which generates the first control signal to select an operating frequency band of the VCO according to the sign of the first frequency comparison result which is output to the first path;
- and
- a gain controller which generates the second control signal to select a target gain range of the VCO according to the sign of the second frequency comparison result which is output to the second path.
10 more elements
A system for generating an oscillation signal, the system comprising:
- a voltage-controlled oscillator (VCO) which generates the oscillation signal corresponding to an oscillation-controlled voltage, in a frequency band which is selected according to a band-adjusted digital value, and a gain range which is selected according to a gain-adjusted digital value;
- a mode determination unit which compares values of first and second frequency comparison results with first and second predetermined threshold values to generate a mode selection signal, from the first and second frequency comparison results between a reference signal and a first feedback signal, which is generated by dividing a frequency of an initial oscillation signal of the VCO by a first number, and the reference signal and a second feedback signal which is generated by dividing a frequency of a first oscillation signal of the VCO in the selected frequency band by a second number;
- a switch which provides signs of the first and second frequency comparison results to first and second paths according to the mode selection signal, and outputs one of a first voltage, a second voltage, and a phase-locked loop (PLL) based variable voltage, as the oscillation-controlled voltage, according to the mode selection signal;
- a band controller which generates the band-adjusted digital value according to the sign of the first frequency comparison result which is output to the first path;
- and
- a gain controller which generates the gain-adjusted digital value according to the sign of the second frequency comparison result which is output to the second path.
3 more elements
A system for generating an oscillation signal, the system comprising:
- a voltage-controlled oscillator (VCO) which generates the oscillation signal corresponding to an oscillation-controlled voltage, in a frequency band which is selected according to a band-adjusted digital value, and a gain range which is selected according to a gain-adjusted digital value;
- a counter which compares first and second count values of pulses of a predetermined clock signal with first and second predetermined periods to generate a mode selection signal;
- a switch which provides signs of first and second frequency comparison results between a reference signal and a first feedback signal, which is generated by dividing a frequency of an initial oscillation signal of the VCO by a first number, and the reference signal and a second feedback signal which is generated by dividing a frequency of a first oscillation signal of the VCO in the selected frequency band by a second number, to first and second paths according to the mode selection signal, and outputs one of a first voltage, a second voltage, and a phase- locked loop (PLL) based variable voltage, as the oscillation-controlled voltage, according to the mode selection signal;
- a band controller which generates the band-adjusted digital value according to the sign of the first frequency comparison result which is output to the first path;
- and
- a gain controller which generates the gain-adjusted digital value according to the sign of the second frequency comparison result which is output to the second path.
3 more elements
A method of generating an oscillation signal corresponding to an oscillation-controlled voltage from a voltage-controlled oscillator (VCO), the method comprising:
- providing signs of first and second frequency comparison results to one of first and second oaths according to a mode selection signal;
- outputting one of a first voltage, a second voltage, and a phase-locked loop (PLL) based variable voltage, as the oscillation-controlled voltage, according to the mode selection signal;
- selecting an operating frequency band of the voltage-controlled oscillator;
- tuning a gain range of the VCO in the selected operating frequency band to generate an output oscillation signal;
- and
- phase-locking the output oscillation signal in the tuned gain range,
- wherein the selecting the operating frequency band comprises:
- comparing a first feedback value corresponding to a frequency of an initial oscillation signal of the VCO and a lower edge frequency of a target frequency curve of the VCO to output the first frequency comparison result;
- adjusting a frequency band of the VCO according to the first frequency comparison result to obtain the selected operating frequency band;
- and
- changing to an operation of the tuning the gain range if a difference between the first feedback value and the lower edge frequency is less than a certain level according to the adjusting the frequency band, or if a predetermined time elapses after starting adjusting the frequency band, and
- wherein the tuning comprises:
- comparing a second feedback value corresponding to a frequency of a first oscillation signal in the selected operating frequency band and a target frequency in the target frequency curve of the VCO to output a the second frequency comparison result;
- adjusting a gain of the first oscillation signal according to the second frequency comparison result to generate the output oscillation signal;
- and
- changing to an operation of the phase-locking the output oscillation signal if a difference between a frequency of the output oscillation signal and the target frequency is less than a certain level according to the adjusting the gain, or when a predetermined time elapses after starting adjusting the gain.
13 more elements
A method of generating an oscillation signal corresponding to an oscillation-controlled voltage using a voltage-controlled oscillator (VCO) in a frequency band which is selected according to a band-adjusted digital value, and a gain range which is selected according to a gain-adjusted digital value, the method comprising:
- comparing values of first and second frequency comparison results with first and second predetermined thresholds to generate a mode selection signal, from the first and second frequency comparison results between a reference signal and a first feedback signal, which is generated by dividing a frequency of an initial oscillation signal of the VCO by a first number, and the reference signal and a second feedback signal which is generated by dividing a frequency of a first oscillation signal of the VCO in the selected frequency band by a second number;
- providing signs of the first and second frequency comparison results to one of first and second paths according to the mode selection signal;
- outputting one of a first voltage, a second voltage, and a phase-locked loop (PLL) based variable voltage, as the oscillation-controlled voltage, according to the mode selection signal;
- generating the band-adjusted digital value according to the sign of the first frequency comparison result which is output to the first path;
- and
- generating the gain-adjusted digital value according to the sign of the second frequency comparison result which is output to the second path.
3 more elements
A method of generating an oscillation signal corresponding to an oscillation-controlled voltage using a voltage-controlled oscillator (VCO) in a frequency band which is selected by a band-adjusted digital value and a gain range which is selected according to a gain-adjusted digital value, the method comprising:
- comparing first and second count values of pulses of a predetermined clock signal with first and second predetermined periods, and generating a mode selection signal;
- providing signs of first and second frequency comparison results between a reference signal and a first feedback signal, which is generated by dividing a frequency of an initial oscillation signal of the VCO by a first number and the reference signal and a second feedback signal which is generated by dividing a frequency of a first oscillation signal of the VCO in the selected frequency band by a second number, to first and second paths according to the mode selection signal;
- outputting one of a first voltage, a second voltage, and a phase-locked loop (PLL) based variable voltage, as the oscillation-controlled voltage, according to the mode selection signal;
- generating the band-adjusted digital value according to the sign of the first frequency comparison result which is output to the first path;
- and
- generating the gain-adjusted digital value according to the sign of the second frequency comparison result which is output to the second path.
3 more elements
A system for generating an oscillation signal, the system comprising:
- a voltage-controlled oscillator (VCO) which generates a plurality of oscillation signals corresponding to an oscillation-controlled voltage;
- a frequency comparator that compares a first feedback value corresponding to a frequency of an initial oscillation signal of the VCO and a lower edge frequency of a target frequency curve of the VCO and a second feedback value corresponding to a frequency of a first oscillation signal in the selected operating frequency band and a target frequency of a target gain range;
- a switch which provides signs of first and second frequency comparison results to first and second oaths according to a mode selection signal, and outputs one of a first voltage, a second voltage, and a phase-locked loon (PLL) based variable voltage, as the oscillation-controlled voltage, according to the mode selection signal;
- and
- a mode controller that selects an operating frequency band of the VCO by adjusting a frequency band of the VCO according to the first frequency comparison result which is output to the first oath, and enables the system to tune a gain range of the VCO in the selected operating frequency band if a difference between the first feedback value and the lower edge frequency is less than a certain level according to the adjustment of the frequency band, or when a predetermined time elapses after starting adjusting the frequency band,
- wherein the VCO phase-locks an output oscillation signal in the tuned gain range corresponding to the target gain range, and
- wherein the mode controller further performs:
- adjusting a gain of the first oscillation signal according to the second frequency comparison result which is output to the second path;
- and
- enabling the VCO to phase-lock the output oscillation signal when a difference between the frequency of the output oscillation signal and the target frequency is less than a certain level according to an adjustment of the gain, or when a predetermined time elapses after starting adjusting the gain.
7 more elements
Dependencies are inferred from the claim text.