Internal Gate Resistance Measurement
Application Notes
Power MOSFET and IGBT internal gate resistance is an important device paramteter, since it can limit the maximum switching frequency or determine the driving loss in switching converters and inverters. For the lower totem pole transistor of the converter output, it is also important to minimize the internal gate resitance to prevent device self turn-on. Device self turn-on is caused by transient currents injected into the gate terminal of the lower totem pole transistor through capacitive coupling when the upper totem pole transistor turns on.
Since this phenomena can cause device destruction, controlling internal gate resistance variations is as important as minimizing the absolute gate resistance value. Unfortunately, most data sheets only show typical values for the internal gate resitance. Since the internal gate resitance has a strong temperature dependence, measuring it for many devices under actual use conditions is necessary to understand its true value and temperature behavior.