A VCO-Based ADC Using Ring Oscillator

This article investigates the potential of Voltage-Controlled Oscillator (VCO)-based Analog-to-Digital Converters (ADCs) that utilize a ring oscillator as their core element. This approach makes the ADC particularly well-suited for applications in the frequency domain. The proposed circuit offers a unique dual functionality, operating seamlessly as both a VCO-ADC and a mixer at the same time. This is achieved through a strategic design of the power supply nodes within the ring oscillator. By leveraging its inherent mixing capability, the circuit streamlines direct signal conversion, eliminating the need for additional mixing stages. Consequently, the low-pass component resulting from the down-conversion process can be directly digitized by the ring oscillator acting as an ADC. This innovative design offers potential benefits such as reduced circuit complexity and lower power consumption.