®
PROFET BTS 740 S2
GND disconnect
Inductive load switch-off energy
dissipation
E
bb
E
AS
V
bb
IN
E
E
Load
L
V
bb
IN
OUT
PROFET
OUT
ST
PROFET
GND
L
=
ST
V
V
V
GND
V
bb
IN
ST
GND
Z
L
{
E
R
R
L
Any kind of load. In case of IN=high is V
OUT
≈ V -V .
IN IN(T+)
Due to V
> 0, no V = low signal available.
ST
GND
Energy stored in load inductance:
2
L
1
E = / ·
L·I
GND disconnect with GND pull up
L
2
While demagnetizing load inductance, the energy
dissipated in PROFET is
V
bb
IN
E = Ebb + EL - ER=
AS
V
·i (t) dt,
ON(CL) L
OUT
PROFET
with an approximate solution for R > 0Ω:
L
ST
I ·L
I ·R
L L
OUT(CL)
L
E =
AS
(V +|V
|) ln (1+
OUT(CL)
)
GND
bb
2·R
|V
|
L
V
V
V
V
IN ST
GND
bb
Maximum allowable load inductance for
4)
a single switch off (one channel)
L = f (I ); T
= 150°C, V = 12 V, R = 0 Ω
Any kind of load. If V
> V - V device stays off
IN IN(T+)
L
j,start
bb
L
GND
Due to V
> 0, no V = low signal available.
ST
GND
Z [mH]
L
1000
100
10
V
load
disconnect with energized inductive
bb
V
high
bb
IN
OUT
PROFET
ST
GND
V
bb
For inductive load currents up to the limits defined by ZL
(max. ratings and diagram on page 10) each switch is
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.
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[A]
I
L
Semiconductor Group
10
2003-Oct-01
INFINEON [ Infineon ]
