Romano Torres 9th January 2013 DC/DC Converters To convert a dc input voltage Vs into a dc output voltage Vo; To regulate the dc output voltage against load and line variations; To reduce the ac voltage ripple on the dc output voltage below the required level; To provide isolation between the input source and the load; From reference  Applications Electronic devices: Internal sub-circuits require different voltage levels; Low battery voltage level needed. Photovoltaic panels: Increase the voltage level of electric current produced. Step-Down Buck Converter Image from reference  Step-Up Boost Converter Image from reference  Buck-Boost Converter Image from reference  Cuk Converter Image from reference  Transparency Resistors Images from reference  Capacitors Transparent thin-film transistors In 2003 appear the first successful reports of TTFT using ZnO as channel layer material   . In 2004, K. Nomura et al. report the successful fabrication of TTFT with a-GIZO (amorphous galliumindium-zinc-oxide) . TTFT device structure Staggered bottom-gate Image from reference  TFT operation modes Cut-off: Pre-saturation: Saturation: No current flow. Vgs<Vt Vgs>Vt Vds>Vgs-Von & Vds<Vgs-Vt a-GIZO TFT limitations p-type devices with poor semi-conductor characteristics; Threshold voltage shift due DC-bias; Source and drain contacts’ resistance influence the TFT characteristics; a-GIZO TFT limitations • Temperature: • Oxygen vacancy. Image from reference  a-GIZO TFT limitations • Light: Image from reference  Transparency Problems with inductors: Poor conductance; High parasitic resistance; Low quality factor. Voltage multipliers Due the various problems with transparent inductors, we propose use voltage multipliers; How does it work? Proposed positive DC/DC Converter Images from reference  Proposed negative DC/DC Converter Images from reference  Transparent photovoltaic panels Image from reference  References  P. F. Carcia, R. S. McLean, M. H. Reilly and G. Nunes, "Transparent ZnO thin-film transistor fabricated by RF magnetron sputtering", Applied Physics Letters, vol.82, no.7, pp. 1117-1119, Feb 2003.  C. Chen, L. Dou, R. Zhu, C. Chung, T. Song, Y. Zheng, S. Hawks, G. Li, P. Weiss, and Y. Yang, “Visibly transparent polymer solar cells produced by solution processing,” in American Chemical Society vol. 6 no.8, 2012, pp. 7185-7190.  R. L. Hoffman, B. J. Norris and J. F. Wager, "ZnO-based transparent thin-film transistors", Applied Physics Letters, vol.82, no.5, pp. 733-735, Feb 2003.  S. Hong, “DC-DC Converters using Indium Gallium Zinc Oxide thin film transistors for mobile display applications,” in Japanese Journal of Applied Physics, 2010.  D. Keszler, R. Presley and J. Wager, Transparent Electronics. New York, USA: Springer, 2008.  S. Kuk, S. Lee, S. Kim, B. Kim, S. Park, J. Kwon, and M. Han, “Light-induced hysteresis of In– Ga–Zn–O thin-film transistors with various temperatures,” in IEEE Electron Device Letters vol. 33 no. 9, 2012, pp. 1279-1281.  S. Lee, S. Kim, Y. Lee, W. Lee, K. Yoon, J. Kwon, and M. Han, “The effect of the photo-induced carriers on the reliability of Oxide TFTs under various intensities of light,” in IEEE Electron Device Letters vol. 33 no. 2, 2012, pp. 218-220.  S. Masuda, K. Kitamura, Y. Okumura, S. Miyatake, H. Tabata and T. Kawai, "Transparent thin film transistors using ZnO as an active channel layer and their electrical properties", Journal of Applied Physics, vol.93, no.3, pp. 1624-1630, Feb 2003.  K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono, “Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors,” in Nature vol. 432, 2004, pp.488–492.  M. Rashid, “DC DC Converters,” in Power Electronics Handbook. San Diego, USA: Academic Press, 2001, pp. 211-224.