Effect of the Transimpedance Amplifier Topology on the Photoplethysmography Signal

Photoplethysmography (PPG) is a widely used technique to extract physiological information non-invasively. Besides other factors, the transimpedance amplifier (TIA) topology choice has an impact on the PPG signal. This study presents a novel quantitative evaluation of seven different resistive TIA topologies in terms of four different Signal Quality Indexes (SQIs): AC amplitude, perfusion index, signal shape quality and signal-to-noise-ratio. Results indicate that a differential TIA configuration is preferred over the single-stage and that while the PD polarity has no impact on the PPG signal quality, the bias choice is important, being the zero bias configuration more beneficial than the reverse bias.