BTS 5210G
Inductive load switch-off energy
dissipation
GND disconnect with GND pull up
E
bb
V
E
bb
IN
AS
E
E
Load
L
OUT
PROFET
V
bb
IN
ST
GND
OUT
PROFET
L
=
ST
V
V
GND
V
V
IN ST
GND
bb
Z
L
{
E
R
R
L
Any kind of load. If V
> V - V device stays off
IN IN(T+)
> 0, no V = low signal available.
ST
GND
Due to V
GND
Energy stored in load inductance:
2
L
1
E = / ·L·I
V
disconnect with energized inductive
L
2
bb
load
While demagnetizing load inductance, the energy
dissipated in PROFET is
E
= Ebb + EL - ER= VON(CL)·i (t) dt,
AS
L
V
high
bb
IN
with an approximate solution for R > 0Ω:
L
OUT
PROFET
I ·L
L
2·R
I ·R
L L
OUT(CL)
E
AS
=
(V +|V
|) ln (1+
OUT(CL)
)
bb
|V
|
ST
L
GND
Maximum allowable load inductance for
4)
a single switch off (one channel)
V
bb
L = f (I ); T
= 150°C, V = 12 V, R = 0 Ω
L
j,start
bb
L
For inductive load currents up to the limits defined by ZL
(max. ratings and diagram on page 10) each switch is
Z [mH]
L
1000
100
10
protected against loss of V
.
bb
Consider at your PCB layout that in the case of Vbb dis-
connection with energized inductive load all the load current
flows through the GND connection.
1
1
2
3
4
5
6
I
[A]
L
Infineon Technologies AG
10
2003-Oct-01
INFINEON [ Infineon ]
