•

AN604: Calculation of conduction losses in a power rectifier

•

AN4021: Calculation of reverse losses on a power diode

1.1

Characteristics (curves)

Figure 1. Average forward power dissipation versus

average forward current (per diode)

0

2

4

6

8

10

12

14

16

18

20

0

2

4

6

8

1 0

12

14

16

18

20

22

24

P

( W)

F(AV)

T

=tp/T

tp

= 1

= 0.05

I

(A)

F(AV)

= 0.5

= 0.2

= 0.1

δ

δ

δ

δ

δ

δ

Figure 2. Average forward current versus ambient

temperature (δ = 0.5, per diode)

0

2

4

6

8

10

12

14

16

18

20

22

0

25

50

75

100

125

150

175

I

(A)

F(AV)

T

=tp/T

tp

Tamb(°C)

R

= 15°C/W

th(j-a)

R

=R

th(j-a)

t h(j-c)

δ

Figure 3. Normalized avalanche power derating versus

pulse duration (Tj = 125 °C)

P

(tp)

P

(10 µs)

ARM

ARM

0.001

0.01

0.1

1

1

10

100

1000

t (µs)

p

Figure 4. Relative variation of thermal impedance junction

to case versus pulse duration

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.E-03

1.E-02

1.E-01

1.E+00

Z

/R

th(j-c)

th(j-c)

t (s )

p

Single pulse

STPS40120C

Characteristics (curves)

DS4231 - Rev 4

page 3/11