Datasheet

Datasheet 22 Rev. 1.1, 2008-02-28
Smart Low Side Power Switch
HITFET - BTS3160D
Protection Functions
7 Protection Functions
The device provides embedded protection functions against over temperature, over load and short circuit.
Note: Integrated protection functions are designed to prevent IC destruction under fault conditions described in the
data sheet. Fault conditions are considered as “outside” normal operation.
7.1 Thermal Protection
The device is protected against over temperature resulting due to overload and / or bad cooling conditions.
The BTS3160D has a thermal latch function. The thermal latch is reset by IN-Low signal. See Figure 18 for the
latch behavior.
The diagram naming refers to Figure 8
IN
Low
High
t
Thermal shutdown
DI
Low
High
t
t
T
J
T
JSD
I
IN
I
INnom
t
0
I
INfault
∆T
JSD
t
dfault
Thermal_fault_latch.emf
Figure 18 Status Feedback via Input Current at Over temperature
7.2 Over Voltage Protection
The BTS3160D is equipped with a voltage clamp mechanism that keeps the Drain-Source voltage V
D
at a certain
level. This stage is also used for inductive clamping.
See “Inductive Output Clamp” on Page 18 for details.
7.3 Short Circuit Protection
The condition short circuit is an overload condition of the device. Dependent on the short circuit resistance the
current increase is more or less steep. In condition of high ohmic short the device heats up and the turn off is due
to over temperature. In condition low ohmic short the device turns off on a threshold current level before the over
temperature condition is detected. In order to allow short current spikes, the turn off occurs with the delay time
t
dSC
. Figure 19 shows the behavior mentioned above. In this example the short circuit always occurs after the
device has switched on under normal load condition - Short circuit type 2. The definitions of voltages and currents
are in respect to
Figure 8. The behavior of V
DI
also depends on R
IN
.