A High Speed ​​Ring Voltage Controlled Oscillator

Abstract

A high-speed ring voltage-controlled oscillator of the present invention is composed of four-stage delay units in series, wherein the negative output terminal (Vout-) of each delay unit is connected to the positive input terminal (Vin+) of the next delay unit, each The positive output terminal (Vout+) of the first-stage delay unit is connected to the negative input terminal (Vin-) of the next-stage delay unit; the negative output terminal (Vout-) of the last-stage delay unit is connected to the negative input terminal (Vout-) of the first-stage delay unit ( Vin-), the positive output terminal (Vout+) of the last-stage delay unit is connected to the positive input terminal (Vin+) of the first-stage delay unit. The invention adds an active inductance structure on the basis of the traditional delay unit, and adds a pair of gate-grounded PMOS transistors at the load end, which ensures that the circuit oscillates in the entire voltage range, provides additional current for the circuit, and improves the oscillation frequency. The frequency control of the delay unit is realized by connecting the control voltage to the gates of a pair of PMOS transistors, which are equivalent to voltage-controlled resistors and play a role in adjusting the oscillation frequency.

Description

technical field [0001] The invention belongs to the field of semiconductor integrated circuit design, and mainly relates to a ring voltage-controlled oscillator with high speed and high tuning linearity. Background technique [0002] A voltage-controlled oscillator (Voltage-Controlled-Oscillator, VCO) is a signal source whose frequency varies with voltage. It is widely used in phase-locked loops, clock recovery and frequency synthesis circuits, and is a key component of these circuits. In integrated circuits, voltage-controlled oscillators can be divided into two categories: ring oscillators and inductor-capacitor oscillators. The noise performance of the LC oscillator is better, but it requires an additional process to integrate the inductor and occupies a larger area. The ring oscillator can be realized by standard CMOS technology, relatively small in area, and has a wide tuning range, which is suitable for system-on-chip. [0003] Ring oscillators can be divided into tw...

AI Technical Summary

Problems solved by technology

The ring oscillator with single-ended structure is simple in structure, occupies a small chip area, and can realize full-swing output, but has poor noise suppression ability to common mode noise and power supply voltage, and poor phase noise.

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