| 摘要 |
PURPOSE: A voltage controlled oscillation circuit including an operation selection function is provided to supply selectively one of two oscillation frequencies by using one switching voltage. CONSTITUTION: A voltage controlled oscillation circuit includes the first voltage control circuit(10), the second voltage control circuit(20), and a power switching circuit portion(30). The first voltage control circuit includes the first resonance portion(11) for providing the first resonant frequency, the first oscillation portion(12) for oscillating the first resonant frequency, and the first buffer portion(13) for outputting the oscillation frequency. The second voltage control circuit includes the second resonance portion(21) for providing the second resonant frequency, the second oscillation portion(22) for oscillating the second resonant frequency, and the second buffer portion(23) for outputting the oscillation frequency. The power switching circuit portion supplies the operating voltage to the first or the second voltage control circuit according to a switching voltage.
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