Features of the SiC diodes

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DocID024196 Rev 1

Figure 3. ST’s STPSC806 first generation: typical forward voltage drop versus

forward current

As a consequence, the working area of SiC rectifiers usually corresponds to

V

leads to an increase of the forward voltage drop with the junction temperature, meaning an

increase of the conduction power losses, hence an increase of the temperature and so on.

This electro-thermal mechanism results in a thermal runaway loop. The effect is explained in

Section 2.

1.3

Other characteristics

1.3.1

Low leakage current

The new generation of 650 V SiC diode offers some low leakage current values similar to

the 600 V Si counterparts. Therefore the reverse power losses defined in PFC by the

Equation 5 stays negligible as showed in Table 1.

Equation 5

with

Equation 6

0

2

4

6

8

10

12

14

16

0.0

IFM (A)

Tj =150 °C

Tj

Tj

Tj

Tj=25 °C

Tj =25 °C

VFM (V)

=175 °C

0.5

1.0

1.5

2.0

2.5

3.0

Table 1. Leakage current and reverse losses comparison in PFC @90Vac between Si

and SiC diode

Product

Typical / Maximum

Typical

STTH8R06D

35 / 400 µA @ 125 °C

0.011

STPSC806D

150 / 1000 µA @ 125 °C

0.047

STPSC8H06D

65 / 335 µA @ 150 °C

0.02

P

(T) =

· V · I (V , T)

REV

j

av

R

R

R

j

d

2 · 2 · V

Ö

in