PLL circuit, calibration method and wireless communication terminal
AssigneePanasonic Corporation
InventorTakahiro Shima
Life of this patent
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Abstract
An ILFD controller sets a control parameter on the basis of a frequency of a frequency-divided signal and a frequency of a reference signal measured by a clock counter. A VCO controller selects an oscillation band that defines an oscillation frequency of a VCO and also selects an oscillation band of the VCO on the basis of the frequency of the reference signal and a frequency of a frequency-divided signal that is a result obtained by frequency-dividing an output signal, which is delivered from the VCO in response to the selected oscillation band, by means of an ILFD and a frequency divider.
Claims10
A PLL circuit comprising:
- a voltage controlled oscillator configured to output a high frequency signal;
- an injection locked frequency divider configured to frequency-divide the output high frequency signal;
- a frequency divider configured to frequency-divide the frequency-divided signal into a frequency of a reference signal;
- a phase frequency detector configured to compare the frequency-divided signal from the frequency divider with the reference signal and configured to output a phase difference and a frequency difference;
- a charge pump configured to convert the output phase difference and the frequency difference into an electric current;
- a loop filter configured to generate a control voltage for the voltage controlled oscillator in accordance with the thus-converted electric current and configured to apply the generated control voltage to the voltage controlled oscillator;
- and
- a calibration circuit configured to control an oscillation band which determines an oscillation frequency of the voltage controlled oscillator and configured to control a control parameter for activating the injection locked frequency divider in a determined operating range, wherein
- the calibration circuit is configured to adjust the oscillation band of the voltage controlled oscillator in accordance with a frequency-divided signal of the adjusted injection locked frequency divider after adjustment of the control parameter of the injection locked frequency divider.
A calibration method comprising:
- deactivating operation of a voltage controlled oscillator configured to output a high frequency signal;
- measuring a frequency of a frequency-divided signal which is obtained by frequency-dividing in accordance with a control signal including a control parameter of an injection locked frequency divider for frequency-dividing the high frequency signal and a frequency of a determined reference signal;
- setting the control parameter of the injection locked frequency divider in accordance with the measured frequency of the frequency-divided signal and the frequency of the reference signal;
- releasing the voltage controlled oscillator from a deactivated state;
- selecting an oscillation band that determines an oscillation frequency of the voltage controlled oscillator;
- and
- selecting the oscillation band of the voltage controlled oscillator on the basis of a frequency of a frequency-divided signal that is obtained by frequency-dividing a signal, which is output from the voltage controlled oscillator according to the selected oscillation band, by means of the injection locked frequency divider and the frequency divider, and a frequency of the reference signal.
Dependencies are inferred from the claim text.