Abstract
A novel ring oscillator is proposed for ultra-low-voltage application. The proposed ring oscillator utilizes the voltage bootstrapping to enhance the oscillation speed at near- and sub-threshold voltage regions. The delay cell for the proposed oscillator is configured with feedforward inputs coming from multiple previous stages for further enhancing the speed with low power consumption. The proposed ring oscillator was designed in a 65-nm CMOS process. Evaluation results indicate that the proposed delay cell has up to 50.8% lower latency with up to 23.5% less power consumption for the supply voltage ranging from 0.35 V to 0.6 V. They also indicated that the oscillation frequency of the proposed ring oscillator was improved by 44.5%∼103.3% as compared to the conventional bootstrapped ring oscillator. For providing the same oscillation frequency, the proposed ring oscillator has 22.6% less power consumption.
