Industrial PhD Project by Ömer Altan

Project Title: CapPIT - High-density Capacitive Power Interposer Technology for 3D Integrated Power Supplies
Supervisors: Flemming Jensen (main supervisor),  Henri Jansen, Tiberiu-Gabriel Zsurzsan, Ahmed Morsi Mohamed Morsi  Ammar, Hoa Thanh Le
 
Project description
As smartphones continue to get smaller, there is an increasing demand for more integrated functions, longer battery life, and greater use time, all while maintaining high levels of power. It has been identified a strong need for power converters that can deliver 2x to 3x more power for fast battery charging. However, current technologies based on printed circuit boards have reached their fundamental limits in terms of heat dissipation, efficiency, and size. Therefore, innovation is required in all areas of power converter technology.

The key requirements for super-fast charger ICs are efficiency and power density, which is the ratio of charging power to IC footprint, as well as conversion efficiency and heat dissipation capacity. The competitive landscape of fast-charging power converters for mobile phones includes several manufacturers, such as MediaTek (US), Analog Devices (US), Qualcomm (US), Broadcom (US), NXP (NL), and Renesas (US). These converters primarily use switched-cap technology and hybrid switched-cap-inductor technology, allowing for input voltage increases from 5V to 12V and 20V, respectively. The most products are discrete solutions assembled on a PCB substrate in side-by-side 2D packages, resulting in a large footprint. To address this issue, 3D integration with stacked components is preferred for smaller footprints. However, this approach is challenging with current technologies due to the lack of low-profile capacitor technology that can be stackable and still remain below 0.85 mm. Therefore, we believe that integrated capacitors will be the key enabler for compact 3D fast-charging solutions. Capacitor integration technology is a significant research topic in both industrial and academic settings. 

In this project, we propose an innovative approach to developing capacitor technology to realize high-density, low-profile capacitors to be used in Lotus’s next switched-capacitor fast-charging converter product. Based on preliminary assessment, we believe unprecedented power density (up to 320% higher) can be achieved in a highly miniaturized footprint (5 x 5mm, 75% smaller) and a low profile (< 1mm) for phone charging solutions.