BTS409L1
GND disconnect with GND pull up
3
IN
Vbb
PROFET
4
ST
GND
1
V
V
bb
V
IN ST
V
OUT
Inductive Load switch-off energy
dissipation
E bb
E AS
Vbb
PROFET
OUT
EL
ELoad
2
5
IN
=
GND
ST
GND
ZL
{
L
RL
ER
Any kind of load. If V
GND >
V
IN
-
V
IN(T+)
device stays off
Due to V
GND
>0, no V
ST
= low signal available.
V
bb
disconnect with energized inductive
load
3
high
2
IN
Vbb
PROFET
4
ST
GND
1
V
OUT
Energy stored in load inductance:
E
L
=
1/2
·
L
·
I
L
While demagnetizing load inductance, the energy
dissipated in PROFET is
E
AS
= E
bb
+ E
L
- E
R
= V
ON(CL)
·
i
L
(t) dt,
2
5
with an approximate solution for R
L
>
0
Ω:
E
AS
=
I
L
·
L
I
L
·
R
L
·
(
V
bb
+ |V
OUT(CL)
|)
·
ln
(1+
)
|V
OUT(CL)
|
2
·
R
L
bb
Maximum allowable load inductance for
a single switch off
L = f (I
L
);
T
j,start
= 150°C,T
C
= 150°C const.,
V
bb
= 12 V,
R
L
= 0
Ω
L
[mH]
10000
Normal load current can be handled by the PROFET
itself.
V
bb
disconnect with charged external
inductive load
S
high
2
IN
3
Vbb
PROFET
4
ST
GND
1
V
OUT
1000
5
D
100
bb
10
If other external inductive loads L are connected to the PROFET,
additional elements like D are necessary.
1
1
2
3
4
5
I
L [A]
Infineon Technologies AG
8
2003-Oct-01
INFINEON [ INFINEON TECHNOLOGIES AG ]
