Booster diode

AN2649

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diode decrease (the current in the boost diode decreases) while the switching losses in SiC

diode are always negligible. Furthermore as the current diode decreases also, the losses

due to the diode in the MOSFET decrease.

Figure 26.

Efficiency curve comparison

The difference in terms of efficiency is also evident if we consider the thermal behavior of

power devices. In Figure 27 we can observe the thermal maps for the MOSFET and Sic

diode compared with the same MOSFET and Silicon diode in the worst case in terms of

losses (Vin = 88 Vac). We note that the MOSFET and diode are compared using the same

heatsinks.

The difference in terms of temperature is 15 °C for the MOSFET and 20 °C for the diode.

This is an important result for reliability as well as in terms of efficiency of the system.

These results allow using a smaller heatsink, saving cost and space.

Figure 27.

Thermal maps comparison -

Si diode

Figure 28.

Thermal maps comparison -

SiC diode

Si diode

MOSFET

SiC diode

MOSFET