Voltage-controlled oscillator based on buffer feedback

Abstract

The invention discloses a voltage-controlled oscillator based on buffer feedback, and belongs to the field of design of radio frequency and millimeter wave terahertz integrated circuits. The voltage-controlled oscillator comprises six NMOS (N-channel Metal Oxide Semiconductor) transistors, two feedback capacitors, four inductors and two varactors, wherein grids of MN1 and MN2 are connected with drains of opposite sides respectively; sources of the MN1 and the MN2 are connected with each other, and connected with a drain connection common end of MN3 and MN4; grid and source connection common ends of the MN3 and the MN4 are connected with a bias voltage and the ground respectively; a common end for connecting one end of one varactor with one end of the other varactor is connected with a voltage control end; the other ends of the two varactors are connected with the drains of the MN1 and the MN2 respectively; a common end for connecting one end of an L1 with one end of an L2 is connected with a power voltage; the other ends of the L1 and the L2 are connected with the drains of the MN1 and the MN2 respectively; an MN5 is connected with an L3, and an MN6 is connected with an L4, thereby constructing buffers respectively; grids of the MN5 and the MN6 are connected with the drains the MN5 and the MN6 respectively; sources of the MN5 and the MN6 are grounded respectively; drains of the MN5 and the MN6 are connected with one end of the L3 and one end of the L4 respectively; the other ends of the L3 and the L4 are connected with the power voltage respectively; one end of one feedback capacitor and one end of the other feedback capacitor are connected with the drains of the MN5 and the MN6 respectively; and the other ends of the two feedback capacitors are connected with the grids of the MN3 and the MN4 respectively. Through adoption of the oscillator, phase noise of a circuit can be lowered, and the loading capability of the circuit is enhanced.

Description

Technical field [0001] The invention belongs to the field of radio frequency and millimeter wave terahertz integrated circuit design, and particularly relates to the structure design of a voltage controlled oscillator with low phase noise, wide frequency band coverage and large load driving capability in the millimeter wave terahertz frequency band. Background technique [0002] Since the 21st century, the explosive growth of information technology has driven the rapid development of the integrated circuit industry. On the one hand, the user’s communication rate requirements are increasing rapidly, making it more and more difficult for the communication speeds of 2G, 3G, 4G, and WLAN to meet the needs of users. On the other hand, low-frequency spectrum resources are also becoming less and less, making some new applications difficult. Find the frequency band within this range. In this context, the application of millimeter waves was born. The millimeter wave band defined by IRTS...

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Problems solved by technology

[0004] In view of this, the purpose of the present invention is to propose a VCO structure based on buffer feedback in order to overcome the deficiencies in the prior art. The present invention is to eliminate the problems of VCO load difficulty, large power consumption, and poor phase noise

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