Transconductance linear broadband LC type voltage-controlled oscillator and adjustable capacitor array circuit

Abstract

The invention discloses a transconductance linear broadband LC type voltage-controlled oscillator and an adjustable capacitor array circuit. The transconductance linear broadband LC type voltage-controlled oscillator comprises an LC oscillation circuit and a first adjustable capacitor array circuit; the LC oscillation circuit is characterized by comprising a first PMOS transistor, a second PMOS transistor, a first three-end differential inductor and a biasing circuit; the grid electrode of the first PMOS transistor is connected with the drain electrode of the second PMOS transistor through a first AC coupling capacitor; the grid electrode of the second PMOS transistor is connected with the drain electrode of the first PMOS transistor through a second AC coupling capacitor; the two symmetrical ends of the first three-end differential inductor are separately connected with the grid electrode of the first PMOS transistor and the grid electrode of the second PMOS transistor; the center tapend of the first three-end differential inductor is connected with the biasing circuit; and the first adjustable capacitor array circuit is connected in parallel with the two symmetrical ends of thefirst three-end differential inductor. The transconductance linear broadband LC type voltage-controlled oscillator and the adjustable capacitor array circuit can be widely applied to various high-frequency local oscillation phase-locked loop systems.

Description

technical field [0001] The invention relates to an LC-type voltage-controlled oscillator, in particular to a transwire linearized broadband LC-type voltage-controlled oscillator and an adjustable capacitor array circuit. Background technique [0002] The voltage-controlled oscillator is an important part of the phase-locked loop, which is used to provide the local oscillator frequency and form the phase-locked loop loop. The core part of the voltage-controlled oscillator is usually composed of an active transconductance device and a resonant circuit, and the resonant circuit forms an oscillation through feedback. The active transconductance device is used to compensate the energy loss of the resonant tank oscillation, so as to generate a continuous and stable oscillation signal. As the core of the phase-locked loop, the voltage-controlled oscillator plays the role of providing the local oscillator frequency. Its oscillation frequency is proportional to its control voltage. ...

AI Technical Summary

Problems solved by technology

The traditional LC-type voltage-controlled oscillator usually cross-couples the gate and drain of the MOS device to form an active transconductance device. Since the oscillation signal swing of the LC-type voltage-controlled oscillator is usually close to or even exceeds the power supply voltage, this makes the Under large-signal working conditions, within the oscillation frequency cycle, the MOS device works in the triode region for nearly half of the cycle, showing transconductance nonlinear characteristics, and cannot obtain good phase noise characteristics

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