Precise Extraction of Dynamic Rdson Under High Frequency and High Voltage by a Double-Diode-Isolation Method

A double-diode-isolation method with low parasitic capacitance devices and reverse clamping is proposed to accurately extract the high-frequency and high-voltage dynamic on-resistance (
$R_{\mathrm{ dson}}$
) of AlGaN/GaN high electron mobility transistor (HEMT) power devices. The response time required for the drain voltage to drop back to the on-voltage of this testing circuit can reach 100 ns, and the forward voltage drop of the isolation diode is monitored in real time using low-voltage probes. A low value constant current source is built to power the testing circuit at only several mA to avoid additional self-heating effect. With these improvements, we can obtain a test frequency of more than 1 MHz, a test voltage of more than 600 V and an accuracy of higher than 97.8% for the extraction of dynamic
$\text{R}_{\mathrm{ dson}}$
.