A Voltage Controlled Oscillator Based on Even-Order Nonlinear Amplitude Feedback

Abstract

The invention discloses a voltage-controlled oscillator based on even non-linear amplitude feedback. The voltage-controlled oscillator comprises an oscillation circuit and a feedback circuit; a current source is eliminated from the oscillation circuit, such that the voltage-controlled oscillator can work under low voltage; negative resistance is provided by utilizing an NMOS cross-coupled transistor, such that energy consumed by an LC resonant loop is compensated; the feedback circuit detects an oscillation amplitude in real time by utilizing an even non-linear theory; output voltage is used as bias voltage after being filtered and then connected to the grid of the transistor; therefore, current of the cross-coupled transistor is reduced; and the oscillation amplitude is controlled. By means of the structure disclosed by the invention, the power consumption of the feedback circuit is low; the grid voltage of the transistor is effectively reduced; the current flowing through the transistor is also reduced; the power consumption of the oscillation circuit can be obviously reduced; furthermore, due to reduction of transconductance of the transistor, the flicker noise can be reduced; the phase noise can be improved; and the invention is applied to the voltage-controlled oscillator in an application occasion having low voltage and low power consumption.

Description

technical field [0001] The invention relates to a voltage-controlled oscillator based on even-order nonlinear amplitude feedback, which belongs to the phase-locked loop technology. Background technique [0002] The voltage-controlled oscillator is an important part of the phase-locked loop, which directly affects the carrier frequency in the radio frequency transceiver, and its performance index will directly affect the performance parameters of the entire radio frequency transceiver. Under low power supply voltage, the design of radio frequency circuits is greatly challenged. In order to ensure that the transistors work in the saturation region, the number of transistors connected in series between the power supply and ground is strictly limited. Therefore, voltage-controlled oscillators at low supply voltages usually have no current source, but this will cause the current in the oscillator circuit to be completely determined by the width-to-length ratio of the transistor, ...

AI Technical Summary

Problems solved by technology

Under low power supply voltage, the design of RF circuits is greatly challenged. In order to ensure that the transistors work in the saturation region, the number of transistors connected in series between the power supply and ground is strictly limited.

Therefore, voltage-controlled oscillators at low supply voltages usually have no current source, but this will cause the current in the oscillator circuit to be completely determined by the width-to-length ratio of the transistor, and power consumption will increase accordingly

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