Datasheet

Datasheet 11 Rev. 1.0, 2008-08-28
Smart High-Side Power Switch
BTS50080-1TEA
Power Stages
Figure 8 Output Clamp
To prevent destruction of the device, there is a voltage clamp mechanism implemented that keeps the voltage drop
across the device at a certain level (
V
ON(CL)
). See Figure 8 and Figure 9 for details. The maximum allowed load
inductance is limited.
Figure 9 Switching an Inductance
5.3.1 Maximum Load Inductance
While de-energizing inductive loads, energy has to be dissipated in the BTS50080-1TEA. This energy can be
calculated via the following equation:
In the event of de-energizing very low ohmic inductances (
R
L
≈0) the following, simplified equation can be used:
The energy, which is converted into heat, is limited by the thermal design of the component. For given starting
currents the maximum allowed inductance is therefore limited. See Figure 10 for the maximum allowed
inductance at V
bb
=12V.
Out put Clam p . emf
OUT
V
bb
VBB
L,
R
L
V
OUT
I
L
V
ON
V
OUT
InductiveLoad. emf
t
I
L
t
V
OUT(CL)
V
bb
ON OFF
V
ON(CL)
EV
ON CL()
V
bb
V
ON CL()
–
R
L
------------------------------------
ln⋅ 1
R
L
I
L
⋅
V
ON(CL)
V
bb
–
-----------------------------------+


I
L
+
L
R
L
----- -
⋅⋅=
E
1
2
-- -
LI
L
2
V
ON(CL)
V
ON(CL)
V
bb
–
-----------------------------------
⋅=