Patent ID: 7432769
Filing Date: 2008-10-07
Classification: H03L

Abstract:
1. An oscillator circuit, comprising: a voltage controlled oscillator having an inductor and a variable capacitor configured to generate an output signal having a frequency of n times of a target frequency; a PLL synthesizer having a programmable counter, a phase detector and a control voltage generation circuit, wherein the programmable counter divides an output signal of the voltage controlled oscillator, the phase detector is configured to detect phase difference between the output signal from the programmable counter and a reference signal, and the control voltage generator circuit is configured to generate a control signal of the voltage controlled oscillator based on the phase information detected at the phase detector so that the voltage controlled oscillator is controlled to generate the output signal having a frequency of n times of the target frequency, a frequency divider circuit provided separately from the PLL synthesizer, dividing the output signal from the voltage controlled oscillator into 1/n frequency and generating at least two signals having an equal frequency and different phases by 180° from each other, wherein a frequency of the voltage controlled oscillator is controlled to be a frequency n times a target frequency so that it is possible to form the inductor and the capacitor of the voltage controlled oscillator on a semiconductor IC, a division ratio of the frequency divider circuit is set to be 1/n so that a frequency of the output signal of the voltage controlled oscillator is made to be 1/n, and the voltage controlled oscillator, the PLL synthesizer, and the frequency divider circuit are formed on a semiconductor integrated circuit.