Low-Voltage Clocked Comparator With Flexible Oxide TFT Technology *

Abstract

This paper presents a novel clocked comparator circuit using amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor technology. The circuit is fabricated on a 30 $\mu \mathrm{m}$ flexible polymide substrate. Experimental characterization took place under normal ambient conditions. The comparator circuit employs inverters using pseudo CMOS topology to obtain better swing. It employs a clocked architecture, where the pre-amplification and regeneration phases are controlled by this clock. From measurements, the circuit is showing a VinCM of 1V - 2.5 V, power consumption of 80 $\mu \mathrm{W}$ average input static offset of 119mV and a swing of 70% at a clock frequency of 5 MHz and an input signal frequency of 5 kHz with a supply voltage $(\mathrm{V}_{\text{DD}})$ of 4 V. This circuit is showing a 62.5% improvement in speed compared to the state-of-the-art work at a relatively low $\mathrm{V}_{\text{DD}}$ using single-gate a-IGZO TFT technology. This circuit finds potential applications in smart sensing systems on flexible substrates.