Datasheet

PROFET
®
BTS 443 P
Data Sheet Page 8 of 15 Rev. 1.0, 2007-02
Reversave (Reverse battery protection)
Logic
IS
IN
IS
R
V
R
OUT
L
R
Power
Signal
V
bb
-
Power
Transistor
IN
R
bb
R
D
R
V
≥1kΩ, R
IS
= 1 kΩ nominal. Add R
IN
for reverse
battery protection in applications with V
bb
above 16V;
recommended value:
1
R
IN
+
1
R
IS
+
1
R
V
=
VV
A
bb
12||
,05.0
−
To minimise power dissipation at reverse battery
operation, the summarised current into the IN and IS
pin should be about 50mA. The current can be
provided by using a small signal diode D in parallel to
the input switch, by using a MOSFET input switch or by
proper adjusting the current through R
IS
and R
V.
Since the current through R
bb
generates additional
heat in the device, this has to be taken into account in
the overall thermal considerations.
V
bb
disconnect with energised inductive
load
Provide a current path with load current capability by
using a diode, a Z-diode, or a varistor. (V
ZL
< 73 V or
V
Zb
< 30 V if R
IN
=0). For higher clamp voltages
currents at IN and IS have to be limited to
250 mA.
Version a:
PROFET
V
IN
OUT
IS
bb
V
bb
V
ZL
Version b:
PROFET
V
IN
OUT
IS
bb
V
bb
V
Zb
Note that there is no reverse battery protection when
using a diode without additional Z-diode V
ZL
, V
Zb
.
Version c:
Sometimes a necessary voltage clamp is given by non
inductive loads R
L
connected to the same switch and
eliminates the need of clamping circuit:
PROFET
V
IN
OUT
IS
bb
V
bb
R
L