A nano-power class-AB current multiplier for energy-based action potential detector

An ultra low-power class-AB four-quadrant current multiplier designed to be used in an energy-based action potential detector is presented. The multiplier is considered the first topology that provides fully class-AB operation. The topology is constituted by a class-AB current amplifier and a current splitter which can handle input signals in excess of ten times the bias current. The proposed circuit operation is based on the exponential characteristic of BJTs or subthreshold MOSFETs. The multiplier is designed using the latter devices and achieves very low power consumption. From a 0.65 V supply, simulation results using 0.13 mum CMOS model parameters show that the proposed circuit consumes 12.4 nW static power while less than -30 dB THD is achieved for an input modulation index up to 10.