Design of Internal Startup Circuit for Implantable Pacemakers using Energy Harvesting Technique

A pacemaker is a small battery operated device that helps the heart to beat in a regular rhythm. It contains a powerful battery, electronic circuits, and computer memory that jointly generate electronic signals. One of the main problems about pacemakers is their batteries. Since the capacity of the batteries is limited, it limits the pacemakers lifetime. The other method to power up the implanted pacemaker is harvesting thermal energy is presented. The designed power supply includes an internal startup circuit and does not need any external battery. The startup circuit having a prestart up charge pump (CP) and a startup boost converter. The prestart up CP used to achieve a high efficiency and reduced voltage drop as well as increased circuit performance consists of a multi feedback ring oscillator. The startup boost converter utilizes a modified maximum PowerPoint tracking scheme (MPPT). According to LTSPICE simulation results, a 40 mV provided from a thermoelectric generator (TEG) and generate an output voltage up to 1.5V. The results show that a power consumption of 1.32pW is obtained from the output of the startup boost converter.