Datasheet

PROFET
®
BTS 443 P
Data Sheet Page 9 of 15 Rev. 1.0, 2007-02
Inductive load switch-off energy
dissipation
PROFET
V
IN
OUT
IS
bb
E
E
E
E
AS
bb
L
R
E
Load
L
R
L
{
Z
L
R
IS
I
IN
V
bb
i (t)
L
Energy stored in load inductance:
E
L
=
1
/
2
·L·I
2
L
While demagnetising load inductance, the energy
dissipated in PROFET is
E
AS
= E
bb
+ E
L
- E
R
=
∫
V
ON(CL)
·i
L
(t) dt,
with an approximate solution for R
L
> 0
Ω:
E
AS
=
I
L
· L
2
·R
L
(V
bb
+ |V
OUT(CL)
|) ln (1+
I
L
·R
L
|V
OUT(CL)
|
)
The device is not suitable for permanent PWM with
inductive loads if active clamping occurs every cycle.
Maximum allowable load inductance for
a single switch off
L = f (I
L
); T
j,start
=
150°C, V
bb
= 12 V, R
L
= 0 Ω
L[mH]
0.01
0.1
1
10
100
0 25 50 75 100
I
L
[A]