Isolated IGBT gate driver with high CMTI, split outputs and safety features

This post is sponsored by Texas Instruments. The Texas Instruments (TI) ISO5452 is a 5.7kV rms, reinforced isolated gate driver for IGBTs and MOSFETs with split outputs, OUTH and OUTL, providing 2.5A source and 5A sink current. The input side operates from a single 2.25V to 5.5V supply. The output side allows for a supply range from minimum 15V to maximum 30V. Two complementary CMOS inputs control the output state of the gate driver. The short propagation time of 76ns assures accurate control of the output stage. An internal desaturation (DESAT) fault detection recognizes when the IGBT is in an overcurrent condition. Upon a DESAT detect, a Mute logic immediately blocks the output of the isolator and initiates a soft-turn-off procedure which disables, OUTH, and pulls OUTL to low over a time span of 2 µs. When OUTL reaches 2 V with respect to the most negative supply potential, VEE2, the gate driver output is pulled hard to VEE2 potential turning the IGBT immediately off. When desaturation is active, a fault signal is sent across the isolation barrier pulling the FLT output at the input side low and blocking the isolator input. Mute logic is activated through the soft-turn-off period. The FLT output condition is latched and can be reset only after RDY goes high, through a low-active pulse at the RST input. When the IGBT is turned off during normal operation with bipolar output supply, the output is hard clamp to VEE2. If the output supply is unipolar, an active Miller clamp can be used, allowing Miller current to sink across a low impedance path preventing IGBT to be dynamically turned on during high voltage transient conditions. The readiness for the gate driver to be operated is under the control of two under-voltage-lockout circuits monitoring the input side and output side supplies. If either side has insufficient supply the RDY output goes low, otherwise this output is high. The ISO5452 is available in a 16-pin SOIC package. Device operation is specified over a temperature range from -40C to 125C ambient.