DC–DC Converters Using Indium Gallium Zinc Oxide Thin Film Transistors for Mobile Display Applications

Abstract

DC–DC converters integrated into a panel are proposed for mobile display applications using indium gallium zinc oxide (IGZO) thin film transistors (TFTs). The proposed positive DC–DC converter uses cross-coupled and diode-connected structures for a high output voltage and a high power efficiency, while the proposed negative DC–DC converter uses also a cross-coupled structure but with separated pumping capacitors for a negative output voltage and a high power efficiency. The simulated results show that the output voltage and power efficiency are 21.3 V and 69.5% for the positive DC–DC converter and -5.1 V and 56.1% for the negative DC–DC converter, respectively, at a supply voltage of 10 V and a load current of 250 µA. The measured results show that the output voltage and power efficiency of the proposed positive DC–DC converter are 20.8 V and 66.6%, respectively, under the same conditions as those for the simulated results.