Semiconductor integrated circuit device for communication

A semiconductor integrated circuit device for communication, which includes a PLL circuit that has a VCO constituted so as to be capable of perform an oscillation operation in multiple frequency bands and that is capable of outputting an oscillation signal having a frequency in accordance with specified frequency information,

• said device comprising a control circuit for performing calibration in such a state that said PLL circuit is a closed loop, oscillating and operating said VCO at a target frequency to measure this tuning voltage per each of frequency bands of said VCO, and selecting a frequency band having a value that is near a threshold value corresponding to said target frequency.

A semiconductor integrated circuit device for communication, which includes a PLL circuit that has a VCO constituted so as to be capable of perform an oscillation operation in multiple frequency bands and that is capable of outputting an oscillation signal having a frequency in accordance with specified frequency information,

• said device comprising a control circuit for performing calibration in such a state that said PLL circuit is a closed loop, oscillating and operating said VCO at a target frequency to measure this tuning voltage per each of frequency bands of said VCO, and selecting a frequency band that is within a range between two threshold values corresponding to said target frequency.

A semiconductor integrated circuit device for communication, including a PLL circuit which has a VCO constituted so as to be capable of an oscillation and operation in multiple frequency bands, a phase comparator for detecting the phase difference between a feedback signal from said VCO and a frequency signal used as a reference, and a charge pump for generating a voltage in response to the phase difference detected by said phase comparator and supplying the voltage to said VCO, and which is capable of outputting an oscillation signal with a frequency corresponding to specified frequency information, the device comprising:

• a memory circuit for memorizing tuning sensitivity information showing dependence of frequency relative to a tuning voltage per each of frequency bands of said VCO;
• and
• a control circuit for controlling a current value of said charge pump at the time of selecting each of the frequency bands of said VCO, in order to compensate for the dependence of the frequency relative to the tuning voltage on the basis of the tuning sensitivity information memorized in said memory circuit when the selected frequency band is compensated for.

A method of calibrating a voltage controlled oscillator which is adapted to operate within each of multiple frequency bands, comprising the steps of measuring the oscillator output frequency at a fixed oscillator input voltage within each frequency band, and saving these measured values as calibration values for reference by a controller when setting the oscillator to generate a required output frequency.

A method of calibrating a voltage controlled oscillator which is adapted to operate within each of multiple frequency bands, comprising the steps of setting the oscillator to a first frequency band;

• measuring the oscillator output frequency at a fixed oscillator input voltage;
• comparing the measured value with a target reference frequency to determine whether or not the measured value matches the target reference frequency, and either selecting said first frequency band for operation of the oscillator if the measured value matches the target reference frequency, or setting the oscillator to a new frequency band and measuring the oscillator output frequency at said fixed oscillator input voltage to obtain a new measured value if the measured value does not match the target reference frequency, and repeating the comparison step using the new measured value and said target reference frequency and acting on the result to either select said new frequency band for operation of the oscillator or setting the oscillator to another new frequency band and repeating the measuring and comparison steps if necessary until a frequency band has been select.

A method of calibrating a voltage controlled oscillator which is adapted to operate within each of multiple frequency bands, comprising setting the oscillator to operate at a target frequency within each of one or more of the frequency bands in succession and comparing the input voltage of the oscillator with a fixed threshold voltage each time to determine whether or not the input voltage is of an acceptable value for voltage control of the oscillator, the oscillator being set to operate in that frequency band which is first determined to have an acceptable input voltage.