Simulation and Analysis of Two GaN MIS-HEMT-Based Step-down Level Shifters

In this paper, two step-down level shifter circuit structures based on AlGaN/GaN (aluminum-gallium-nitride/gallium-nitride) MIS-HEMTs (metal-insulator-semiconductor-high-electron-mobility-transistors) are proposed. The level shifter circuits have the capability to produce voltage drop. They are used to address the challenges of anomalous operation state in the sawtooth wave generator of PWM (pulse width modulation) integrated circuit, while also mitigating the undesirable device degradation resulting from high output voltage from the comparator. Proposed circuit structures are simulated and calibrated by the ADS (Advanced Design System) platform. Additionally, calculations are carried out to analyze the principle of output voltage drop. Subsequently, the circuit output characteristics and parameter settings of these circuit structures are discussed, which offer insights and advice regarding their feasibility and the potential of step-down level shifter circuit structures for monolithically integrated GaN power converters.