PLL circuit, calibration method and wireless communication terminal
First Claim
Patent Images
1. 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, whereinthe 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.
1 Assignment
0 Petitions
Accused Products
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.
-
Citations
10 Claims
-
1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. 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.
-
Specification