Thermoelectric Energy Harvesting for Implantable Medical Devices.

A thermoelectric energy harvesting system is proposed to supplement the primary power supply of an implantable medical device. A low-power synchronous boost converter capable of boosting 10mV input voltage to 1V output voltage is designed in a 180nm CMOS process. To increase the charging speed, a maximum power transfer scheme is utilized. The harvester delivers up to 10µW power with a minimum temperature gradient of 1-degree, which results in a power efficiency over 40%.Clinical Relevance- The use of this technology could enhance the longevity of battery-operated implanted medical devices by reducing the possibility of invasive battery replacement surgery.

A 1.5 ns OFF/ON switching-time voltage-mode LVDS driver/receiver pair for asynchronous AER bit-serial chip grid links with up to 40 times event-rate dependent power savings.

This paper presents a low power fast ON/OFF switchable voltage mode implementation of a driver/receiver pair intended to be used in high speed bit-serial Low Voltage Differential Signaling (LVDS) Address Event Representation (AER) chip grids, where short (like 32-bit) sparse data packages are transmitted. Voltage-Mode drivers require intrinsically half the power of their Current-Mode counterparts and do not require Common-Mode Voltage Control. However, for fast ON/OFF switching a special high-speed voltage regulator is required which needs to be kept ON during data pauses, and hence its power consumption must be minimized, resulting in tight design constraints. A proof-of-concept chip test prototype has been designed and fabricated in low-cost standard 0.35 µ m CMOS. At ± 500 mV voltage swing with 500 Mbps serial bit rate and 32 bit events, current consumption scales from 15.9 mA (7.7 mA for the driver and 8.2 mA for the receiver) at 10 Mevent/s rate to 406 µ A ( 343 µ A for the driver and 62.5 µA for the receiver) for an event rate below 10 Kevent/s, therefore achieving a rate dependent power saving of up to 40 times, while keeping switching times at 1.5 ns. Maximum achievable event rate was 13.7 Meps at 638 Mbps serial bit rate. Additionally, differential voltage swing is tunable, thus allowing further power reductions.