Patent ID: 7863994
Filing Date: 2011-01-04
Classification: H03B

Abstract:
1. A voltage controlled oscillator fabricated on an integrated circuit, the voltage controlled oscillator comprising: a semiconductor substrate; a voltage controlled oscillator disposed on the semiconductor substrate, the voltage controlled oscillator core comprising an active element, a first terminal and a second terminal; a primary inductor disposed on the semiconductor substrate, the primary inductor comprising a first terminal and a second terminal, wherein the first terminal of the primary inductor is coupled to the first terminal of the voltage controlled oscillator core, and wherein the second terminal of the primary inductor is coupled to the second terminal of the voltage controlled oscillator core; a secondary inductor disposed on the semiconductor substrate, the secondary inductor comprising a first terminal and a second terminal, wherein the secondary inductor is magnetically coupled to the primary inductor to affect a magnitude of an effective inductance of the primary inductor a variable impedance element coupled to the first and second terminals of the secondary inductor; the active element comprises a first transistor and a second transistor, each transistor comprising a first terminal, a second terminal, and a control terminal, wherein the second terminal of the first transistor is coupled to the first terminal of the voltage controlled oscillator core, the second terminal of the second transistor is coupled to the second terminal of the voltage controlled oscillator core, the control terminal of the first transistor is coupled to the second terminal of the voltage controlled oscillator core and the control terminal of the second transistors coupled to the first terminal of the voltage controlled oscillator core; the primary and secondary inductors comprise metal spiral inductors fabricated on the semiconductor substrate; and the variable impedance element comprises a transistor, the transistor comprising a first terminal, a second terminal, and a control terminal, the control terminal coupled to a control voltage, wherein the control voltage controls the effective inductance the first and second terminals of the primary inductor.