IGBT Structure

IGBT structure

It includes a three-terminal device: gate G, collector C and emitter E (as shown in the attached figure).

The figure shows a-N-channel VDMOSFET combined with GTR - N-channel IGBT.

The IGBT has an additional layer of P+ injection area than the VDMOSFET and has a strong through-current capability.

The simplified equivalent circuit shows that the IGBT is a Darlington structure consisting of a GTR and MOSFET, a PNP transistor with a thick base region driven by the MOSFET.

RN is the modulation resistance within the base region of the transistor.

Characteristics of GTR - Bipolar type, current driven, with conductance modulation effect, very high through-current capability, low switching speed, high driving power required. Current control element.

Advantages of MOSFET - unipolar type, voltage driven, fast switching speed, high input impedance, good thermal stability, voltage control element.

IGBT Features

The gate is voltage-driven, the driving circuit is simple, and the driving power required is small.

High operating frequency, small switching loss, only 1/10 of GTR when the voltage is above 1000V.

High withstand voltage, high current-carrying density, high input impedance, small through-state voltage drop, good thermal stability, no "once-through" problem.

Simple driving circuit, large safe working area, strong current handling capability, no buffer circuit.

It is possible to achieve high current control with small voltage.