PLL circuit, calibration method, and wireless communication apparatus

摘要

In the stop state of a VCO and an injection locked frequency divider, an ILFD controller sets the control parameter of an injection locked frequency divider on the basis of the frequencies of a reference signal and the frequency-divided signal measured according to the control parameter of the injection locked frequency divider. While the injection locked frequency divider is operated and in the stop state of the VCO, the ILFD controller sets the control parameter of the injection locked frequency divider on the basis of the frequencies of the reference signal and the frequency-divided signal measured according to the control parameter of the injection locked frequency divider.

主权项

1. A PLL circuit comprising:
a voltage controlled oscillator that outputs a high-frequency signal; a first injection locked frequency divider that generates a first frequency-divided signal obtained by frequency-dividing the output high-frequency signal; a second injection locked frequency divider that generates a second frequency-divided signal obtained by frequency-dividing the first frequency-divided signal; a frequency divider that generates a third frequency-divided signal obtained by frequency-dividing the second frequency-divided signal so as to be a frequency of a reference signal; a phase and frequency comparator that compares the third frequency-divided signal with the reference signal and that outputs the difference between phase and frequency; a charge pump that converts the output difference into current or voltage; a loop filter that generates the control voltage of the voltage controlled oscillator according to the converted current or voltage and that applies the generated control voltage to the voltage controlled oscillator; and a calibration circuit that selects an oscillation band for determining the oscillation frequency of the voltage controlled oscillator, and that adjusts a first control parameter of the first injection locked frequency divider and a second control parameter of the second injection locked frequency divider, for operating the first injection locked frequency divider and the second injection locked frequency divider at different operation bands, wherein after adjusting the second control parameter, the calibration circuit adjusts the first control parameter, and adjusts the oscillation band of the voltage controlled oscillator according to the third frequency-divided signal.