WIDE-BAND VOLTAGE CONTROLLED OSCILLATOR USING DEGENERATION RESISTORS

摘要

A wide-band voltage controlled oscillator using a degeneration resistor is provided to minimize power consumption and reduce a phase noise by switching a degeneration resistor. A wide-band voltage controlled oscillator using a degeneration resistor includes a resonant unit(100), a Gm cell unit(200), a first degeneration circuit unit(300), and a second degeneration circuit unit(400). The resonant unit is resonated at a frequency determined by a capacitance and an inductance which are varied by a tuning voltage. The Gm cell unit is composed of a coupled of cross-coupled transistors, and is coupled to the resonant unit. A Gm is determined by a flowing current. The Gm cell unit has first and second MOS transistors which output first and second frequency signals having a different phase by providing power for an oscillation in response to the Gm to the resonant unit. The first degeneration circuit unit includes a plurality of first degeneration resistors and a plurality switches, and adjusts a current flowing on the first MOS transistor. The first degeneration resistors are coupled in parallel with each other between a ground and the first MOS transistor. The switches select each of the first degeneration resistors. The second degeneration circuit unit includes a plurality of second degeneration resistors and a plurality switches, and adjusts a current flowing on the second MOS transistor. The second degeneration resistors are coupled in parallel with each other between the ground and the second MOS transistor. The switches select each of the second degeneration resistors.