| 摘要 |
PROBLEM TO BE SOLVED: To provide a PLL circuit that selects a low conversion coefficient for a voltage controlled oscillator, which constitutes the PLL circuit, so as to improve the stability of an oscillated frequency thereby reducing jitters in an oscillated signal. SOLUTION: A phase comparator circuit 201 compares the phase of a reference signal Sref with a phase of an oscillation signal SVCO, a charge pump 203 and a low-pass filter 206 generate a control signal VCNT in response to the comparison result, gives the control signal to a channel forming region of a PMOS transistor(TR), which is a component of each inverter of a voltage- controlled oscillator VCO 207 for controlling the oscillated frequency of the VCO, then a conversion coefficient KV of the VCO can be set lower, thereby realizing the stability of the oscillated frequency and reduction in the jitter of the oscillated signal SVCO.
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