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

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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.

Published In : IJCAT Journal Volume 3, Issue 11

Date of Publication : November 2016

Pages : 472-476

Figures :10

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J. Stella Mary : PG student, Department of ECE, Vivekanandha College of engineering for women, Tiruchengode, Namakkal (Dt).

Dr. D. Sasikala : Head/ECE, Department of ECE Vivekanandha College of engineering for women, Tiruchengode, Namakkal (Dt).

Pacemakers, battery, Thermal Energy Harvesting, TEG, pre-startup circuits, startup converter

The designed power supply with the internal startup circuit for pacemaker is presented in this paper. A multi feedback oscillator and a Charge Pump (CP) have been designed and simulated in LTspice, which enable the circuit to start up from input voltages up to 300mV. Applying a 300mV input voltage from pre-startup charge pump, which generate an output voltage of the startup boost converter is 1.15V and consume power is 1.32pW under 50kilo ohm load conditions. In future work, the steady state boost converter with multiplexer circuit is added to the startup boost converter to analysis the overall circuit performance and reducing the power consumption.

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