This paper presents two DC-DC converters capable of generating either positive or negative output DC voltage using amorphous-indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs). While one uses conventional diode-connected cross-coupled (design-1), the other employs a bootstrapped cross-coupled (design-2) DC-DC converter, which overcomes the limitations of design-1 but requires boosted clock pulses. Therefore, an on-chip clock booster is proposed to generate all the required signals without any external clock pulses. The performance of the proposed circuits (DC-DC converters and clock booster) has been demonstrated using in-house a-IGZO TFT models in the Cadence environment. The simulation results have shown that design-1 (design-2) generates negative or positive output DC voltage of 7.25 V (7.8 V) or 12.7 V (15.2 V), respectively, for a supply voltage of 8 V, using a single DC-DC converter. Therefore, the output DC voltage of design-2 is close to the theoretical value, and it ensures robust performance against different load currents when compared with design-1. Besides, design-2 has shown a maximum power efficiency of 90%, superior compared with design-1, where power efficiency is 60.7%. Therefore, this circuit finds potential applications in the next generation flexible displays.

Original languageEnglish
Pages (from-to)394-405
Number of pages12
JournalInternational Journal of Circuit Theory and Applications
Issue number3
Publication statusPublished - 1 Mar 2020


  • a-IGZO TFTs
  • bootstrapped
  • clock booster
  • DC-DC converter
  • flexible displays


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