0.5 V RMS-to-DC Converter Topologies Suitable for Implantable Biomedical Devices

In this paper, we propose RMS-to-DC converter topologies. The required current-mode squarer is implemented using appropriately configured non-linear transconductors, the averaging filter using the concept of Sinh-Domain filtering, and the current squaring stage using the translinear principle. Due to employment of an enhanced topology of divider in current averaging topology, capacitor values reasonable for on-chip implementation even for sub Hertz frequencies could be realized. This makes the proposed schemes suitable for being embedded in implantable biomedical devices. The performance of the proposed topologies has been verified through simulation and comparison results. As a biomedical application example, the design of a system for detecting the heart arrhythmia is presented.