Voltage control oscillator for a semiconductor device

摘要

This invention provides a voltage control oscillator that can reduce swing width and more precisely can control a period of the oscillator by applying a back bias voltage to a back bias terminal of a transistor so that an output pulse of the oscillator is controlled. The present invention comprises a plurality of inverters which are connected to each other in the form of a chain, each inverter having a pull up device and a pull down device; a first control block connected to a bulk of each pull up device to supply a desired voltage to said bulk so that threshold voltage of each pull up device is controlled; and a second control block connected to a bulk of each pull down device to supply a desired voltage to said bulk of each pull down device so that threshold voltage of each pull down device is controlled. The present invention can precisely control the oscillator since variation width of the period is small and can minimize a circuit without addition of a buffer since swing width is constant.