A CMOS inductor-less PMIC with MPPT and burst control for a 600 μW magnetoelectric transducer

Recharging the battery of a biomedical implant has been a major topic for several decades. Access to the device requires an often heavy surgical intervention involving huge costs for the health system, not to mention the discomfort suffered by the patient. Hence, remotely supplying the implant is a more than desirable solution. In this context, a miniaturized magnetoelectric transducer working in the ultrasound range has been proposed to remotely power a biomedical implant. Here, a monolithic integrated chip is proposed to efficiently extract the transducer energy. It includes an ultra-low-power, inductor-less, self starting up power management unit. Energy extraction is performed by an active voltage doubler with an efficiency of 88.3 % while extracting 626 μW. A Maximum Power Point Tracker ensures a maximum efficiency keeping the transducer at its maximum power point. Then, the voltage is boosted with a cross-coupled charge pump and the energy is stored in a reservoir before supplying the payload in short periodic bursts through a Low Dropout voltage regulator that may provide up to 280 μJ/burst.