| 摘要 |
PROBLEM TO BE SOLVED: To make a ring oscillator suitable for acceleration, to reduce power consumption and to make the duty factor of a final output signal close to a prescribed value by providing the final output signal having a frequency higher than the oscillation frequency of an oscillation circuit. SOLUTION: Differential circuits 1-3 differentially amplify two signals supplied to a non-inverting input terminal and an inverting input terminal and output them from an inverted output terminal and a non-inverted output terminal. The odd number stages of differential circuits 1-3 are connected in ring while inverting the phases of input and output, and a signal outputted from one differential circuit is once circulated in the ring with delay, inputted to the same differential circuit with inverted phase and oscillated at a frequency determined by the delay time of the differential circuits 1-3. Concerning the outputs of the differential circuits 1-3, the phase is deviated by 2π/3=120 deg. for each output and a sum signal C0 synthesized by transistors QN1-QN3 has a frequency which is triple of the oscillation frequency of the oscillation circuit. Sum signals C0 and C1 are converted to the unbalance signals of duty factor 50% by a comparator 7 and outputted through an inverting buffer 8.
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