A Fully-Integrated Efficient Power Management System for Micro-Scale Biomedical Applications

This paper presents a fully integrated power management system suited for biomedical implanted devices. The proposed system employs a reconfigurable capacitor-based step-up DC-DC converter. The proposed DC-DC converter can provide fractional voltage conversion ratio (VCR) in a step of 0.25 to support wide input range from 0.4-1.2 V providing a constant output voltage of 1.6 V. The system efficiency is optimized using a real-time monitoring for the input current supplied to the DC-DC converter. This allows the system, using a control sequence, to adaptively optimize the number of stages and switching frequency that will provide the required constant output voltage while maintaining optimum efficiency. The proposed system is designed using a 180nm CMOS technology. Simulation results show that the proposed system provides peak efficiency of 78.1%.