A 99.95% Current Efficient Temperature Invariant All-in-One Reference Circuit on Flexible Substrate

This work presents a sub-100 nW all-in-one voltage and current reference circuit implemented using 600 nm indium gallium zinc oxide (IGZO) thin-film transistor (TFT) on a flexible substrate. The proposed design integrates both voltage and current references into a single, simple, and compact architecture. By employing NMOS-only devices with negative feedback, the circuit achieves temperature compensation over a temperature range from 10 °C to 100 °C through a stabilized zero temperature coefficient (ZTC) bias point, enhancing the temperature coefficients (TCs). Simulation results demonstrate that the circuit provides a stable reference current of 78.14 nA and a reference voltage of 1.153 V at room temperature (27 °C), with TCs of 99.6 ppm/°C and 263.6 ppm/°C, respectively. The line sensitivities (LS) are 1.276%/V for the current reference and 0.319%/V for the voltage reference over a supply voltage range from 1.5 V to 5 V making it suitable for integration into both flexible electronics and even conventional Si-based CMOS circuits. The circuit achieves a current efficiency of 99.95% and occupies an area of 0.0183 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.