AN3432

Application constraints

Doc ID 019041 Rev 1

13/24

Figure 9.

STPS20L45C and STPS2045C reverse losses versus junction

temperature

The reverse losses curves, shown in Figure 9, are calculated in the following application

conditions:

Section 2.3.2.

In application conditions, the solar module efficiency lost due to bypass diodes is around

0.05% for STPS20L45 and 0.004% for STPS2045.

The diode with the lower forward voltage (STPS20L45C) has the drawback of a higher

leakage current. The consequence is not visible on power module efficiency due to the low

level contribution of the bypass diode reverse losses.

However, it impacts the diode choice since the leakage current is directly linked with thermal

runaway risk. To avoid this phenomenon the choice of a diode with higher forward voltage is

mandatory as described in Section 3.1.2.

0

1

2

3

4

5

6

7

8

9

10

-40

-20

0

20

40

60

80

100

120

140

160

180

200

Prev (W)

STPS2045C

STPS20L45C

VR = 25 V

Tj (°C)