Full-Swing Clock Generating Circuits on Plastic Using a-IGZO Dual-Gate TFTs With Pseudo-CMOS and Bootstrapping

As clock signals are usually supplied by external rigid ICs, they may limit mechanical flexibility of devices fabricated on plastic. Reported in this letter is a full-swing clock generating circuit that is integrated on a plastic substrate. The clock signal is generated by a 13-stages ring oscillator (RO), which is implemented by n-type-only dual-gate amorphous-indium-gallium-zinc-oxide thin-film transistors. By combining bootstrapping and pseudo-CMOS inverting, an output peak-peak voltage (V
_p-p
) that reaches the supply voltage (V
_DD
) and a high speed, reaching an output frequency of 360 kHz, are achieved. In addition, a phase modulating capacitor is implemented in the RO to increase the high voltage level holding time and the addition of a buffer in the circuit is also studied for the achievement of two antiphase outputs.