Oscillation circuit

Abstract

An oscillation circuit includes a resonance circuit and an amplifier circuit. The resonance circuit includes an inner capacitor to be disposed inside a semiconductor integrated circuit, and an outer capacitor and an outer inductor to be disposed outside the semiconductor integrated circuit. The amplifier circuit includes an input terminal and an output terminal both connected to the resonance circuit. Further, the resonance circuit includes a first closed circuit portion including the inner capacitor, the outer inductor, and a first wiring portion for connecting the inner capacitor and the outer inductor. The resonance circuit further includes a second closed circuit portion including the outer capacitor, the outer inductor, and a second wiring portion for connecting the outer capacitor and the outer inductor. The second closed circuit portion has a wiring resistance smaller than that of the first closed circuit portion.

Description

technical field [0001] The present invention relates to an oscillation circuit capable of high frequency oscillation. Background technique [0002] Conventionally, an oscillation circuit composed of a resonant circuit composed of an inductor and a capacitor and a transistor has been used in a wireless device. By using a varactor diode as a capacitor, a voltage-controlled oscillator circuit (VCO: voltage controlled oscillator, voltage-controlled oscillator) is configured, and frequency control is possible. In addition, a phase synchronization circuit (PLL: Phase-locked loop, phase-locked loop) can be formed by this voltage-controlled oscillation circuit, a phase comparator, a loop filter, and a frequency divider, and can be used in a PLL frequency synthesizer. [0003] In recent years, oscillation circuits as described above have been formed as part of semiconductor integrated circuits. As a method of forming an oscillation circuit as a part of a semiconductor integrated ci...

AI Technical Summary

Problems solved by technology

[0014] When such a high-frequency current flows in the resonant circuit, electromagnetic waves are emitted from the conductive material constituting the current path of the resonant circuit, and the substrate potential of the semiconductor element fluctuates, deteriorating the characteristics of other circuits in the semiconductor integrated circuit

For example, the characteristics of semiconductor integrated circuits that cause a drop in so-called reception sensitivity deteriorate

[0015] In order to solve the above problems, it is conceivable to reduce the oscillation amplitude, but if the oscillation amplitude is reduced, the purity of the oscillation signal will deteriorate, so it is difficult to use this method

In addition, widening the interval between the oscillation circuit and other circuits, or providing a shield between the oscillation circuit and other circuits is considered, but it is difficult to use this method because the area and cost of the semiconductor integrated circuit increase.

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