Oscillating circuit

Abstract

An oscillating circuit includes N nodes outputting oscillating signals, a main loop circuit including N inverting circuits, and a plurality of auxiliary loop circuits. Each inverting circuit in the auxiliary loop circuits is connected in parallel with even numbers of inverting circuits cascaded in the main loop circuit. The circuits for feeding back signals from outputs to inputs of the respective inverters of the main loop circuit have circuit configurations equivalent to each other. Each inverting circuit in the main loop circuit and the auxiliary loop circuits drives an output line such that a phase of an output signal is inverted with respect to a phase of an input signal and has driving power that becomes lower when the phases of the output signal and the input signal are inverted with respect to each other than when the output signal and the input signal are in phase with each other.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]The present invention is a Continuation application of application Ser. No. 11 / 723,819, filed on Mar. 22, 2007, which contains subject matter related to Japanese Patent Application JP 2006-098667 filed with the Japan Patent Office on Mar. 31, 2006, the entire contents of which being incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an oscillating circuit that generates oscillating signals using inverting circuits cascaded in the form of a ring, and particularly to an oscillating circuit that can control oscillation frequency.[0004]2. Description of the Related Art[0005]PLL (phase-locked loop) circuits are widely used to generate an oscillating signal with a high spectral accuracy or generate a clock signal locked in frequency and phase to a data signal. Examples of applications of the PLL circuit include radio communications of portable telephones and the lik...

AI Technical Summary

Benefits of technology

The patent text discusses various techniques for improving the performance of voltage-controlled oscillators (VCOs) used in electronic circuits. The technical effects of these techniques include reducing sensitivity to power supply voltage variations, improving phase noise performance, and reducing jitter and phase noise. However, each technique has its limitations, such as increased current consumption or reduced circuit symmetry. The patent proposes a new VCO design that combines the features of differential and single-ended VCOs to achieve better performance.

Problems solved by technology

In addition, the ring VCO does not have structural symmetry with respect to a power supply line and a ground line, and does not have excellent jitter and phase noise characteristics.

Therefore the differential VCO is improved in terms of device noise and current consumption, but essentially has the same problems as described above.

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