AN4544 datasheet(19/35 Pages) STMICROELECTRONICS

19 / 35 page

DocID026535 Rev 1

19/35

AN4544

Datasheet explanation

2.5.1

Collector-to-emitter saturation voltage - VCE(sat)

VCE(sat) is the on-state collector-to-emitter voltage drop and represents the IGBT power

dissipation during conduction time. This voltage is a function of collector current (IC) gate-

emitter voltage (VGE) and junction temperature (TJ) and so it is specified at the rated IC,

VGE = 15 V and TJ = 25 °C, 125 °C and 175 °C. The IGBT is used as a switch and the range

of VCE is within the saturation region. Increasing VGE rises the channel conductivity and

reduces VCE(sat), while increasing the collector current also increases the VCE(sat).

Figure 14. Cross section of a trench field-stop IGBT

From the equivalent circuit, VCE(sat) is given by:

Equation 8

where:

•

VBE(PNP) is the base-emitter voltage of PNP transistor (see Figure 16)

•

IMOS is the drain current of the Power MOSFET

•

RS is the resistance of the conductivity modulated n-region

•

RCH is the channel resistance of the Power MOSFET

Furthermore VCE(sat) is temperature sensitive and decreases according to the temperature

rise (negative temperature coefficient) until a certain crossover point is reached, after which

VCE(sat) begins increasing (positive temperature coefficient).

CE sat

()

BE PNP

()

MOS

()

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