A Bootstrap Voltage Clamping Circuit for Dynamic VTH Characterization in Schottky-Type p-GaN Gate Power HEMT

A multi-functional bootstrap voltage clamping circuit is proposed for characterizing the drain-bias-induced dynamic V
TH
, in which the GaN HEMT serves as the key bootstrapping device. This new testing setup covers a wide range of OFF-state drain bias (V
DSQ
) up to the voltage rating of GaN power HEMT, a short OFF-to-ON (or stress-to-sense) delay (T
delay
) of 60ns, a high switching frequency (f
sw
) up to 2MHz, and a wide OFF-state static stress time (T
stress
) from 0.5µs to 399s. The dynamics of the threshold voltage (V
TH
) shift in 650-V Schottky-type p-GaN gate HEMT under short- and long-term static stress conditions and temperature-dependent dynamic V
TH
characteristics are systematically investigated using the proposed circuit.