Ring-Amplification Technique for Bio-Signal LNA Designs

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. Abstract Low power wireless medical electronic design is a heated research topic due to the development of remote medical diagnosis systems and long-term treatment assistances. In general, such medical devices contain bio-signal sensor that monitor the health status of a patient or health-conscious person. Our main goal is to design an LNA that is suitable for amplifying bio-signals in low-power remote sensing devices. In this work, the business strategy and the IP strategy is being studied and presented. Ring-amplification technique is a novel amplifier design approach, which has the potential to achieve high gain with minimal power dissipation. The motif behind applying ring-amplification technique to low-power LNA design is that ring-amplifier has the potential to achieve high gain with low power dissipation as well as a relatively simple structure. This work reviews the current status of ring-amplifier design, as well as explores the ring-amplifier design process. The original ring-amplifier approach is not suitable for low-noise amplifier design due to its single-ended structure, therefore effort is being made to modify the ring-amplifier structure to make the amplifier suitable for employing flicker noise cancellation techniques. The eventual result of this work, the differential input ring-amplifier employing chopper stabilization, which achieved closed-loop gain of 63.93dB, THD-78dB, UGB of 12MHz and a positive phase margin which indicates the stability of the ring-amplifier. At 10Hz the output noise voltage density is 120uV/(Hz) 1/2 , which is approximately an order of magnitude noise reduction at low frequencies, compared to the simple ring-amplifier.