VOLTAGE CONTROLLED OSCILLATION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To solve a problem that a conventional voltage controlled oscillation circuit has an adverse effect on other circuits because a steep rising of a voltage waveform across both terminals of an integration capacitor injects a consider ably high spike current to an IC substrate through a parasitic capacitance resulting in fluctuating a potential of the IC substrate. SOLUTION: The ring oscillator type voltage controlled oscillation circuit consisting of a plurality of stages of logic buffer circuits connected in cascade and adopting a configuration that an output of a final stage logic buffer circuit is inverted and fed back to a 1st stage logic buffer circuit. Each of the logic buffer circuits consists of a gain stage 11 consisting of a differential amplifier circuit and a filter stage 12 consisting of a primary low pass filter.