AN2785 datasheet(29/51 Pages) STMICROELECTRONICS

29 / 51 page

AN2785

Application examples

Doc ID 14785 Rev 1

29/51

Figure 21.

Total equivalent circuit for turn-OFF

Given the equivalent circuits in Figure 21 and the approximations on the power IGBT’s

(MOSFET) switching behavior, the timings are the following.

As above, CISS_max is used because when the Vce (or Vds) of the power IGBT (or

MOSFET) is minimum (equal to Vce_sat), the CISS (which depends on the Vce) shows its

maximum value.

Even if they are just approximations, Tfall and Trise are very important values to be

estimated because they provide an indication about the power dissipation during the

switching of the power IGBT (or MOSFET), which can be approximated as indicated in

Figure 22

RGATE

RDSon_sink

Cge = Ciss_max

Vge

Isink

Toff

RGATE

RDSon_sink

Vge_p

Isink

Trise

()

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

⋅

Vge

VCC

max

ISS

GATE

sin

DSon

OFF

(

)

Vge

GATE

sin

DSon

SINK

RISE

⋅

AN2785 Datasheet(PDF) 29 Page - STMicroelectronics

AN2785 Datasheet(HTML) 29 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

Datasheet Download

Link URL