an-990| Application Note
Application Note AN-990
Application Characterization of IGBTs
Table of Contents
Page I. Gate Drive Requirements ................................................................................ 1 I. A Impact of the impedance of the gate drive circuit on switching losses............ 1 I. B Impact of the gate drive impedance on noise sensitivity................................. 2 I. C Impact of gate drive impedance on "dynamic latching" .................................. 2 I. D Using gate voltage to improve short circuit capability..................................... 3 I. E Contribution of "common emitter inductance" to the impedance of the gate drive circuit............................................................................................................ 3 I. F Gate charge vs. input capacitance.................................................................. 3 II. Switching Trajectories and Safe Operating Area Considerations .............. 4 III. Conduction Losses........................................................................................ 5 III. A Calculating the v
oltage drop from data sheet parameters ............................ 6 III.B Conduction model.......................................................................................... 6 IV. Losses in Hard Switching ............................................................................. 7 IV.A Calculation of switching losses with an ideal diode from data sheet information ............................................................................................................ 7 IV.B Calculation of switching losses with an ideal diode from switching model .... 7 IV.C Contribution of the diode reverse recovery ................................................... 8 V. Trade-Off Between Conduction And Switching Losses: Device Optimization ........................................................................................................ 8 VI. The Analysis: Methods To Calculate Junction Temperature And Power Dissipation For A Given Operating Condition................................................ 12
VII. Brief Notes On Thermal Design................................................................. 13 VIII. Replacing MOSFETs With IGBTs ............................................................. 14 VIII.A Power Dissipation ..................................................................................... 14 VIII. B Selecting IGBTs ....................................................................................... 16
