| 摘要 |
PROBLEM TO BE SOLVED: To provide a ring oscillator which achieves a higher frequency as compared with a conventional ring oscillator. SOLUTION: A ring oscillator is provided, in a main loop circuit consisting of four inverters 20-1, 20-2, 20-3 and 20-4, with four sets of two three-stage excitation circuits formed by combining five inverters ([20-1, 20-5, 20-6, 20-7, 20-8], [20-2, 20-9, 20-10, 20-11, 20-12], [20-3, 20-13, 20-14, 20-15, 20-16], [20-4, 20-17, 20-18, 20-19, 20-20]). The number of loop circuits on the even stage formed by four sets of excitation circuits is equal to or smaller than the number of the main loop circuits. The ring oscillator can oscillate at a high frequency because the number of loop circuits on the even stage is smaller as compared with that of a conventional ring oscillator. COPYRIGHT: (C)2010,JPO&INPIT
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