Overview
1
Overview
The ISO5851 is a 5.7-kV
RMS
, reinforced isolated, IGBT gate driver with 2.5-A source and 5-A sink currents.
The primary side operates from a single 3-V to 5.5-V supply. The output side allows for a supply range
from minimum 15-V to maximum 30-V. Two complementary CMOS inputs control the output state of the
gate driver. The short propagation time assures accurate control of the output stage.
An internal desaturation detection recognizes when the IGBT is in an overload condition. Upon a
desaturation detect, the gate driver output is driven low to V
EE2
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
primary side low and blocking the isolator input. The FLT output condition is latched and can be reset
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 V
EE2
. 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 dynamically turned on during high voltage transient
conditions.
The readiness for the gate driver to be operated is under the control of two undervoltage-lockout circuits
monitoring the primary and secondary supplies. If either side have insufficient supply, the RDY output
goes low, otherwise the output is high.
2
ISO5851 Evaluation Module
SLLU218 – June 2015
Copyright © 2015, Texas Instruments Incorporated
