CMOS Ring Amplifier for Bio-Signal LNA

Low power wireless medical devices have attracted great research interests, which need the low noise amplifier (LNA) to amplify bio-signals. And power efficient amplification in scaled CMOS technologies remains a persistent challenge. Ring amplification technique, with a similar structure to CMOS ring oscillators, has the potential to achieve high gain with minimal power dissipation as well as efficient amplification in scaled environments. CMOS ring amplifiers possess the benefits of scalable power-delay production and efficient slew-based charging. So, the application of the ring amplification technique to low power LNA design is investigated in the paper. The approach of ring amplifier with single-ended structure is not suitable for LNA design. Then the pseudo differential amplifier with float sampling scheme is proposed, which is suitable for the purpose of noise reduction with chopper technique. This structure can also eliminate the need for additional common mode feedback in differential processing of signals. Experiments simulation has verified that the bio-signal can be properly processed with the provided design.