Datasheet

Data Sheet 14 Rev.1.0, 2008-04-29
BTS4175SGA
Protection Mechanisms
6 Protection Mechanisms
The device provides embedded protective functions. Integrated protection functions are designed to prevent the
destruction of the IC from fault conditions described in the data sheet. Fault conditions are considered as “outside”
normal operating range. Protection functions are designed for neither continuous nor repetitive operation.
6.1 Loss of Ground Protection
In case of loss of the module ground, where the load remains connected to ground, the device protects itself by
automatically turning OFF (when it was previously ON) or remains OFF, regardless of the voltage applied on IN
pin. In that case, a maximum
I
(OUTGND)
can flow out of the output.
6.2 Undervoltage Protection
Below V
SOP_min
, the under voltage mechanism is met. If the supply voltage is below the under voltage mechanism,
the device is OFF (turns OFF). As soon as the supply voltage is above the under voltage mechanism, then the
device can be switched ON and the protection functions are operational.
6.3 Overvoltage Protection
There is a clamp mechanism for over voltage protection. To guarantee this mechanism operates properly in the
application, the current in the zener diode
Z
DAZ
has to be limited by a ground resistor. Figure 9 shows a typical
application to withstand overvoltage issues. In case of supply greater than
V
S(AZ)
, the power transistor switches
ON and the voltage across logic section is clamped. As a result, the internal ground potential rises to
V
S
- V
S(AZ)
.
Due to the ESD zener diodes, the potential at pin IN rises almost to that potential, depending on the impedance
of the connected circuitry. Integrated resistors are provided at the IN pin to protect the input circuitry from
excessive current flow during this condition.
Figure 9 Over voltage protection with external components
IN
ST
R
IN
R
ST
ZD
ESD
GND
OUT
V
S
V
BAT
R
GND
ZD
AZ
LOGIC
Overvoltage protection single with diag.vsd