BTS 640 S2
V
disconnect with charged external
bb
inductive load
4
V
high
3
1
bb
IN
ST
IS
6
7
OUT
OUT
PROFET
D
5
GND
2
R
L
L
V
bb
If other external inductive loads L are connected to the PROFET,
additional elements like D are necessary.
Inductive Load switch-off energy
dissipation
E
bb
E
AS
4
E
E
Load
L
V
bb
3
IN
6
7
OUT
OUT
1
5
ST
IS
PROFET
=
V
GND
2
bb
E
R
Energy stored in load inductance:
2
L
1
E = / ·L·I
L
2
While demagnetizing load inductance, the energy
dissipated in PROFET is
EAS= Ebb + EL - ER= VON(CL)·iL(t) dt,
with an approximate solution for RL > 0Ω:
IL·L
2·RL
IL·RL
|VOUT(CL)|
E =
AS
·(Vbb +|VOUT(CL)|)· ln (1+
)
Semiconductor Group
Page 10
2003-Oct-01
INFINEON [ Infineon ]
