Patent ID: 8604885
Filing Date: 2013-12-10
Classification: H03K,H03L

Abstract:
1. A voltage control oscillator comprising: a voltage-current converter circuit that converts an inputted frequency control voltage to a current according to a value of the voltage; a current mirror circuit that outputs a current depending upon an input from the voltage-current converter circuit; a ring oscillator including differential inverters connected in multiple stages; an inverting amplifier; and a buffer, wherein the voltage-current converter circuit supplies the current obtained by converting the frequency control voltage to the inverting amplifier by a current mirror formed by a combination of a plurality of transistors in the voltage-current converter circuit and the inverting amplifier, the inverting amplifier inputs, in a clipping transistor of the ring oscillator, a voltage which changes depending upon the frequency control voltage by the current supplied from the voltage-current converter, and the ring oscillator provides the current converted by the voltage-current converter circuit and the current mirror circuit as a tail current and a load current and provides the voltage supplied by the inverting amplifier as a clipping voltage, uses the tail current, the load current, and the clipping voltage to output an amplitude-limited signal from each of the differential inverters and outputs an oscillatory frequency in response to the output signal.