Oscillator-based ADCs: An exploration of time-mode analog-to-digital conversion

This paper introduces two novel ideas within the field of time-mode oscillator-based analog-to-digital conversion. In the form of a self-injection-locked ring-oscillator (SILRO), a method is presented to inherently linearise the voltage-to-frequency (V-F) characteristic, while an alternative proposal of an ultra-low-power (ULP), ultra-low-voltage (ULV) VCO-based analog-to-digital converter (ADC) operating in weak-inversion at a supply of 0.2 V is suitable for high power efficiency, direct energy harvesting applications. The ideas are distinctly separate in concept and physical implementation, but through the common platform of Verilog-A behavioural modelling, a unified methodology applicable to both architectures is proposed for system level exploration and performance evaluation.