Communication semiconductor integrated circuit device and wireless communication system
1 Assignment
0 Petitions
Accused Products
Abstract
The invention provides a communication semiconductor integrated circuit device (RF IC) capable of pulling in the frequency of a PLL circuit to a desired set frequency at high speed even in the case where a frequency settable range of the PLL circuit is wide without providing a current source other than a current source for charging and discharging in an normal operation. An oscillator as a component of a PLL circuit is constructed so as to be operative in a plurality of bands. In a state where a control voltage of the oscillator is fixed to a predetermined value, an oscillation frequency of the oscillator is measured in each of bands and stored in a storing circuit. A set value for designating a band supplied at the time of PLL operation is compared with the stored measured frequency value. From a result of comparison, a band to be actually used in the oscillator is determined, and a frequency difference between the maximum frequency of the selected band and the set frequency is obtained. Further, a control voltage closest to the set frequency is determined on the basis of the frequency difference and the frequency variable range of the selected band and the control voltage is applied to the oscillator to start oscillating operation. After that, a PLL loop is closed and locked.
-
Citations
32 Claims
-
1-22. -22. (canceled)
-
23. A semiconductor integrated circuit device for a wireless communication system, comprising:
-
an oscillation means for generating an oscillation signal having an oscillation frequency in accordance with frequency instruction information, including;
a phase detection circuit which detects a phase difference between a reference signal of a predetermined frequency and a feedback signal;
a charge pump circuit for generating a first voltage in response to the phase difference detected by the phase detection circuit; and
an oscillation circuit for oscillating on the basis of a second voltage of a filter capacitor charged/discharged by the charge pump circuit;
a storing means for storing measured frequency information of the oscillation circuit;
a frequency band determination means for comparing the measured frequency information stored with the frequency instruction information, and generating a signal for determining an oscillation frequency band of the oscillation circuit;
a voltage generation means for generating a third voltage applied to the filter capacitor or the oscillation circuit on the basis of the measured frequency information adapted to an oscillation frequency band determined by the frequency band determination means stored in the storing means and the frequency instruction information;
a switching means for subjectively supplying the first voltage according to an output of the charge pump circuit or the third voltage generated by the voltage generation means as a control voltage of the oscillation circuit; and
a control means for controlling the switching means, wherein the third voltage generated by the voltage generation means is supplied as an initial voltage to either the filter capacitor or the oscillation circuit by the switching means to perform a sink operation at start of operation of the oscillation means, and the switching means is switched to supply the control voltage according to an output of the charge pump circuit to the oscillation circuit to set the oscillation frequency of the oscillation means. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
-
-
32. A wireless communication system comprising:
-
a semiconductor integrated circuit device; and
a baseband circuit, the semiconductor integrated circuit device comprising;
an oscillation means for generating an oscillation signal having an oscillation frequency in accordance with frequency instruction information, including;
a phase detection circuit which detects a phase difference between a reference signal of a predetermined frequency and a feedback signal;
a charge pump circuit for generating a first voltage in response to the phase difference detected by the phase detection circuit; and
an oscillation circuit for oscillating on the basis of a second voltage of a filter capacitor charged/discharged by the charge pump circuit;
a storing means for storing measured frequency information of the oscillation circuit;
a frequency band determination means for comparing the measured frequency information stored with the frequency instruction information, and generating a signal for determining an oscillation frequency band of the oscillation circuit;
a voltage generation means for generating a third voltage applied to the filter capacitor or the oscillation circuit on the basis of the measured frequency information adapted to an oscillation frequency band determined by the frequency band determination means stored in the storing means and the frequency instruction information;
a switching means for selectively supplying the first voltage according to an output of the charge pump circuit or the third voltage generated by the voltage generation means as a control voltage of the oscillation circuit; and
a control means for controlling the switching means, wherein the third voltage generated by the voltage generation means is supplied as an initial voltage to either the filter capacitor or the oscillation circuit by the switching means to perform a sink operation at start of operation of the oscillation means, and the switching means is switched to supply the control voltage according to an output of the charge pump circuit to the oscillation circuit to set the oscillation frequency of the oscillation means, the baseband circuit extracts data from a reception signal down-converted to a desired frequency by the communication semiconductor integrated circuit device and converts transmission data to I and Q signals, and designated frequency information is supplied from the baseband circuit to the semiconductor integrated circuit device.
-
Specification