Absolute Value Circuit for Biological Signal Processing Applications

This paper presents a subtreshold high precision absolute value for biological signal processing applications. The circuit is constituted by a class-AB current amplifier which can handle input signals in excess of several times the bias current. The absolute value operation is based on the MOS transistors biasing in subthreshold region. Thus the proposed circuit offers ultra-low power consumption. The circuit also produces a clean output waveform. The proposed circuit is simulated using 0.5 μm CMOS process from MOSIS. The simulation results show that the circuit provides ultra-low-power consumption and high precision rectification which can be used in biological signal processing.