Design of multiple-stacked current recycling linear regulators for biomedical implants

In this paper we present a novel multiple-stacked current recycling linear regulating power supply circuit for biomedical implants. In implantable neural stimulation systems, high-voltage power supplies are required for electrode actuation purposes while a number of low-voltage supplies generated by linear regulators are dedicated to power electronic systems. We design a multiple-stacked linear regulating power supply with our unique current recycling technique in a 0.35 μm high-voltage CMOS process with full considerations of safe operations as well as process variations and mismatch. In the implemented triple-stacked linear power supply circuit, Monte Carlo simulation results demonstrate the maximum power supply uncertainties on low-voltage power rails are less than 6.9% and a power saving factor as well as current efficiency up to 65.5% and 96.4% respectively can also be achieved.