Patent ID: 8212625
Filing Date: 2012-07-03
Classification: H03B

Abstract:
1. A differential voltage-controlled oscillator (VCO) using center-tapped cross-coupling of a transformer, comprising: a resonant circuit including: a first amplification circuit including first and second PMOS transistors connected between a power supply and the first node and between the power supply and the second node, respectively, and differentially amplifying and outputting the oscillation frequency output from the resonant circuit; and a second amplification circuit including first and second NMOS transistors connected between the third node and a fifth node and between the fourth node and the fifth node, respectively, and differentially amplifying and outputting the oscillation frequency output from the resonant circuit, wherein the first NMOS transistor and the second NMOS transistor are differentially cross-coupled to the second PMOS transistor and the first PMOS transistor, respectively, through the transformer.