| 摘要 |
PURPOSE:To provide a ring oscillator for which the changeable oscillation frequency band of oscillation signals is wide. CONSTITUTION:In an inverter group composed by serially connecting five stages from an inverter G1 to the inverter G5, the output of the inverter G3 is connected through a transfer gate TF 1 to the input of the inverter G1 of an initial stage and the output of the inverter 5 is connected through the transfer gate TF 2 to the input of the inverter G1. Then, when switching signals S3 are 'L,' the CMOS transfer gates TF 1 and TF 2 are set so as to be respectively turned ON and OFF, three inverters G1-G3 are loop connected, the inverters G4 and G5 are made function as buffers for receiving the output of the inverter G3 and the oscillation signals S2 by the inverters G1-G3 of a three-stage loop are obtained from an output terminal 2. On the other hand, when the switching signals S3 are 'H,' setting is performed so as to obtain the oscillation signals S2 by the inverters G1-G5 of a five-stage loop. |
