A Novel Ring Amplifier with Low Common-Mode Voltage Variation and Noise Reduction Using Floating Power Technique

This paper proposed a floating power (FP) technique suitable for the switched-capacitor (SC) circuits. The FP generates an isolated voltage power supply, which reduces the output noise compared to the traditional power supply technique. It is scaling-friendly since it only requires a capacitor and a non-overlapping clock. A self-biased ring amplifier (RAMP) utilizing the FP technique is designed to verify the proposed technique. The simulation result has proved excellent effectiveness in common voltage locking and noise reduction. The common voltage variation reduces to less than 50% compared to the traditional auto-zero (AZ) technique. Besides, the FP technique has less correlation with PVT variation. The proposed RAMP’s output common voltage depends on the preset voltage of the floating capacitor during the charging phase. Therefore, the proposed RAMP removes the dedicated CMFB circuits.