VOLTAGE CONTROLLED RING OSCILLATOR WITH LARGE FREQUENCY RANGE AND VARIABLE DUTY CYCLE

Abstract

Voltage controlled oscillator (VCO) is one of the most important basic blocks
for analog, digital as well as in mixed signal circuits. This paper presents a new
technique to improve the performance of ring oscillators. A VCO with large
tuning range and variable duty cycle is designed using 90nm complementary
metal-oxide-semiconductor (CMOS) technology with supply voltage of 1.8Vp-p.
The simulation results demonstrate that VCO has high frequency range from
100Hz to 1.77GHz and the duty cycle is adjustable 20% - 80% independent from
the oscillation frequency. Simulation results reveal the better performance of the
proposed design as compared to existing current starved ring VCO in terms of
oscillation frequency and power consumption.