BTS307 Datasheet, PDF (8/13 Pages) Siemens Semiconductor Group – Smart Highside Power Switch (Overload protection Current limitation Short circuit protection Thermal shutdown)

Vbb disconnect with charged external
inductive load
S
3
high
IN
Vbb
2
PROFET
OUT
5
D
ST
4
GND
1
Vbb
If other external inductive loads L are connected to the PROFET,
additional elements like D are necessary.
BTS 307
Inductive Load switch-off energy
dissipation
E _bb
IN
Vbb
E _AS
ELoad
PROFET ^OUT
=
ST
EL
GND
L
{Z _{L RL}
ER
Energy stored in load inductance:
E_L = ^1/2·L·I^2L
While demagnetizing load inductance, the energy
dissipated in PROFET is
∫ ^{EAS= Ebb + EL - ER= VON(CL)·iL(t) dt,}
with an approximate solution for R_L > 0 Ω:
E_AS=
2I^L·R^{· L}_L^·(Vbb
+
|V_OUT(CL)|)·
ln
(1+
I_L·R_L
|V_OUT(CL)|
)
Semiconductor Group
8