A Low-Power 0.6-V Quadrature VCO With a Coupling Current Reuse Technique

A novel quadrature voltage-controlled oscillator (QVCO) featuring low power consumption is proposed in this brief. By utilizing the coupling current reuse technique, the coupling current of one core is shared as a source to bias the quadrature coupling device in the other core. Thus, the coupling current consumption is eliminated. Moreover, the injected tank current is reshaped to reduce noise injection and increase efficiency. The coupling current reuse technique allows the proposed QVCO to achieve at least 50% power consumption decreasing compared to previous LC-QVCOs without sacrifices of phase noise and swing. In addition, the quadrature coupling topology is reused as an oscillation detector for dynamic bias control to further decrease power consumption of oscillation cores. A prototype of the proposed QVCO is designed and fabricated in a 40-nm CMOS process. Measurement results indicate that the QVCO achieves a phase noise of -118.6 dBc/Hz@1 MHz at the carrier of 1.575 GHz. The power consumption of the proposed QVCO is only 1.32 mW under the supply voltage of 0.6 V.