Abstract
Lactic acid is one of the human's metabolites transported from cells to blood. The increase of lactic acid due to hypoxia is significantly useful in aiding the quick formation of emergent medical treatment. For example, by detecting the increase of lactic acid in the blood during surgery, it is possible to quickly determine whether the patient's body is deprived of oxygen. The increment of fetal lactate concentration during childbirth can be monitored to prevent fetal hypoxia. In addition to prompt medical responses, lactic acid level can also be applied to diagnose abnormal metabolism due to acute or chronic illness. This paper presents an innovative wireless power transmission system designed to power a wearable non-enzymatic lactic acid monitoring device. The power transmission system comprises a composite magnetoelectric (ME) receiver made of a Galfenol magnetostrictive disc bonded on PZT piezoelectric material. The ME receiver is connected to a dedicated power management circuit and a supercapacitor for energy storage. Two rectification schemes are compared in terms of power efficiency, and the use of a discontinuous mode (DCM) buck-boost converter is considered to maximize the transmitted power and minimize the recharging time.