High frequency ring oscillator using capacitor based level shift circuits

This paper proposes a novel high frequency ring oscillator. The proposed ring oscillator consists of CMOS inverters which use simple capacitor based level shift circuits. The level shift circuit consists of only a capacitor and a MOSFET. Its power consumption is ideally zero. Thanks to the level shift circuits, transconductance and drain conductance of MOSFETs in CMOS inverters increase and high oscillation frequency is achieved. Validity of the proposed method is confirmed by simulations. The simulation results show that oscillation frequency of the proposed circuit is 2.7 times as high as that of conventional circuit.