Smart High-Side Power Switch
BTS5231-2GS
Protection Functions
4.2.2
Reverse Polarity Protection
In case of reverse polarity, the intrinsic body diode causes power dissipation. Additional
power is dissipated by the integrated ground resistor. Use following formula for
estimation of total power dissipation
P
diss(rev)
in reverse polarity mode.
P
diss(rev)
=
∑
V
bb
(
V
DS(rev)
⋅
I
L
)
+
-------------
-
R
GND
2
(3)
The reverse current through the intrinsic body diode has to be limited by the connected
load. The current trough sense pins IS1 and IS2 has to be limited (please refer to
maximum ratings on
The over-temperature protection is not active during
reverse polarity.
4.2.3
Over Voltage Protection
In addition to the output clamp for inductive loads as described in
there is
a clamp mechanism for over voltage protection. Because of the integrated ground
resistor, over voltage protection does not require external components.
As shown in
in case of supply voltages greater than
V
bb(AZ)
, the power
transistor opens and the voltage across logic part is clamped. As a result, the internal
ground potential rises to
V
bb
-
V
bb(AZ)
. Due to the ESD zener diodes, the potential at pin
IN1, IN2 and SEN rises almost to that potential, depending on the impedance of the
connected circuitry.
VBB
IN
IS
R
IN
ZD
AZ
SEN R
SEN
ZD
ESD
logic
R
GND
GND
OUT
V
OUT
OverVoltage .emf
Figure 12
Over Voltage Protection
4.2.4
Loss of Ground Protection
In case of complete loss of the device ground connections, but connected load ground,
the BTS5231-2GS securely changes to or keeps in off state.
Data Sheet
16
V1.2, 2008-09-01
INFINEON [ INFINEON TECHNOLOGIES AG ]
