Towards a Pulse-Based Lithium Polymer Battery Charger with Simple Built-in Resistance Compensation in Biomedical Applications

Abstract

This paper presents a battery charger designed for biomedical devices in wireless power transfer (WPT) system that compensates for the effects of built-in resistance (BIR) and utilizes pulse current parameters optimized for the target battery model. The latched comparator with low kickback noise introduced for BIR compensation accurately detects the battery cell voltage, enabling the realization of a compact chip size without the need for additional complex calculation circuitry. Compared to the conventional constant current/ constant voltage (CC/CV) charging method, the charging time is reduced by approximately 17.5%. In addition, it has the smallest size of about 0.017mm2 and simplest implementation compared to other systems capable of BIR detection.