Gate driver with 10 / 15ns in-transition variable drive current and 60% reduced current dip

Abstract

In various fields, there is a growing need for electric motor drives and inductive power converters. To achieve better switching behavior and lower EME in inductive switching applications, very precise gate control of the power MOSFETs by the gate driver is required. The driver presented in this paper can operate at voltages up to 60V, and it is able to change the gate current in 10 / 15ns (rise / fall delay) within a range of 20mA to 500mA. Achieved by a class B buffer in the output stage, this enables multiple current changes in a 100ns switching transition. A dip in the output current, caused by parasitic capacitances, is reduced from 80% of the full scale current to 20% by a cascode configuration in the driver output stage. The gate voltage is clamped to 11.5V, with a precise clamping circuit to reduce RDS,on with the full gate current, but without stressing the gate oxide with any over voltage. By fully integrating this concept in 130nm HV-BiCMOS, a reduction in external components for limiting overshoot, stress and EME can be achieved.