High Speed and Wider Swing, Level Shifter using Low-Temperature Poly-Silicon Oxide TFTs

We report the CMOS level shifter (LS) made of p-type low-temperature poly-Si (LTPS) TFT using blue laser annealing (BLA) of amorphous Si (a-Si) and an n-type amorphous indium-gallium-zinc oxide (a-IGZO) TFT. Two cascaded inverters with the bootstrap capacitor are utilized. 1-clock signal and 2-supply voltage are employed to obtain a full output swing from high output voltage to ground. For an input swing of (2-10) V, the proposed LS shows a shifted output swing of (10-30) V. Having the fast rise time of 688 ns, it operates in the broad clock frequency range of 1 ∼ 500 kHz. The operating clock frequency, ‘rail-to-rail’ level shifting and faster rise time confirm its superiority.