Power-saving technology for voltage-controlled ring oscillators and sigma-delta modulators based on a voltage-controlled ring oscillator

摘要

A voltage controlled ring oscillator (VCRO) and a VCRO based sigma-delta modulator with the ability to activate and deactivate the VCRO cells. A VCRO includes a plurality of inverters coupled in a ring and a transition detector. The transition detector detects a transition of a first inverter and sends a control signal to activate a second inverter when the transition of the first inverter is detected. The transition detector can comprise a comparator, which is designed to compare an input and an output of one or more inverters in order to detect the transition of the first inverter, and a latch, which is designed to hold the control signal until it is reset .