Inductive load switch-off energy
dissipation
E bb
E AS
IN
Vbb
ELoad
PROFET OUT
=
ST
GND
L
{Z L
EL
ER
RL
Energy stored in load inductance:
EL
=
1/2·L·I
2
L
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 > 0 Ω:
EAS= 2IL·R· LL(Vbb + |VOUT(CL)|)
ln
(1+
IL·RL
|VOUT(CL)|
)
Maximum allowable load inductance for
a single switch off (one channel)5)
L = f (IL ); Tj,start = 150°C, Vbb = 12 V, RL = 0 Ω
L [mH]
1000
100
10
1
1
1.5
2
Semiconductor Group
2.5
3
IL [A]
10
BTS 711 L1