AN2649

Booster diode

9/20

In Figure 3 a switching cycle of the MOSFET device is reported, while in Figure 4, 5, 6, 7

and Figure 8, 9, 10 and 11 are showed the turn-on and the turn-off MOS waveform for

several input voltage and in full load condition (400 V/ 0.5 A).

Figure 3.

Switching cycle waveforms for MOSFET

In the Table 1 are reported the energy loss at turn-on and turn-off versus Vin.

We observe that the value of switching losses in the worst case (Vin=88 Vac) is very close

with the value estimated in the design procedure equal to the sum of (Equation 3) and

(Equation 4):

Equation 10

Table 1.

MOSFET energy losses using SiC diode

Vin [Vac]

Eon [uJ]

Eoff [uJ]

88

14.1

6.3

110

12

6

220

9

6

264

9

5.9

P

SW

Eon

Eoff

+

() fsw

14.1

6.3

+

()uJ 100kHz 2.04 W

=

⋅

=

⋅

=