Abstract: A ring oscillator-based analog-to-digital converter (ADC). The ring oscillator-based ADC includes a ring oscillator and a transition detector. The ring oscillator may include a set of inverters coupled in a ring wherein an output of an inverter is coupled to an input of a successive inverter in the ring. The transition detector is configured to detect transitions of outputs of the inverters by comparing outputs of two separate inverters at two consecutive time instances. The transition detector may include two sets of registers configured to store outputs of the set of inverters at two consecutive time instances, respectively, and a set of comparators configured to compare the outputs stored in the two sets of registers. Each comparator may be configured to compare an output of one inverter at a first time instance and an output of another inverter at a second time instance.

Abstract: A voltage-controlled ring oscillator (VCRO) and a VCRO-based sigma delta modulator having capability of enabling and disabling 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 enable a second inverter if the transition of the first inverter is detected. The transition detector may include a comparator configured to compare an input and an output of an inverter(s) to detect the transition of the first inverter and a latch configured to hold the control signal until it is reset.

Abstract: A ring oscillator-based analog-to-digital converter (ADC). The ring oscillator-based ADC includes a ring oscillator and a transition detector. The ring oscillator may include a set of inverters coupled in a ring wherein an output of an inverter is coupled to an input of a successive inverter in the ring. The transition detector is configured to detect transitions of outputs of the inverters by comparing outputs of two separate inverters at two consecutive time instances. The transition detector may include two sets of registers configured to store outputs of the set of inverters at two consecutive time instances, respectively, and a set of comparators configured to compare the outputs stored in the two sets of registers. Each comparator may be configured to compare an output of one inverter at a first time instance and an output of another inverter at a second time instance.

Abstract: A voltage-controlled ring oscillator (VCRO) and a VCRO-based sigma delta modulator having capability of enabling and disabling 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 enable a second inverter if the transition of the first inverter is detected. The transition detector may include a comparator configured to compare an input and an output of an inverter(s) to detect the transition of the first inverter and a latch configured to hold the control signal until it is reset.