Datasheet

Data Sheet 11 V1.5, 2012-08-17
TLE 8102 SG
Smart Dual Channel Powertrain Switch
Electrical and Functional Description of Blocks
Maximum Load Inductance
During demagnetization of inductive loads, energy has to be
dissipated in the TLE8102SG. This energy can be
calculated with following equation:
EV
DS(CL)
V
bat
V–
DS(CL)
R
L
-------------------------------------
ln⋅ 1
R
L
I
D
⋅
V
bat
V–
DS(CL)
-------------------------------------
–
⎝⎠
⎜⎟
⎛⎞
I
D
+
L
R
L
------
⋅⋅=
The equation simplifies under the assumption of R
L
= 0:
E
1
2
---
LI
D
2
1
V
bat
V
bat
V–
DS(CL)
-------------------------------------
–
⎝⎠
⎜⎟
⎛⎞
⋅=
The energy, which is converted into heat, is limited by the thermal design of the component.
5.3.3 Protection Functions
The TLE8102SG provides embedded protective functions. Integrated protection functions are designed to prevent
IC destruction under fault conditions described in this data sheet. Fault conditions are considered “outside” the
normal operating range. Protection functions are not designed for continuous repetitive operation.
Over load and over temperature protection
s are implemented in the TLE8102SG. Figure 8 gives an overview pf
the protective functions.
OUTn
SPI
INn
temperature
monitor
current
limitation /
shutdown
gate control
T
Tn
GND
SCLK
Input Control
SI
SO
FAULT
CLn
ST Status
CS
Figure 8 Protection Functions
5.3.3.1 Over Load Protection
The TLE8102SG is protected in case of over load or short circuit of the load. If the device is programmed for
current limitation (current limit 1), the current is limited to
I
DS(lim1)
. After time t
d(fault)
, the corresponding over load
flag CLn is set. If usin
g the status outputs for diagnosis, the over load flag is cleared immediately after the over
load condition is no longer present. If using the SPI interface and fault pin for diagnosis, the over load flag of the
affected channel is cleared by the rising edge of the
CS signal after a successful SPI transmission.
If the TLE8102SG is programmed for current shutdown (
current limit 2), the current threshold is I
DS(lim2)
. However,
unlike in current limit 1, after time
t
d(fault)
, the affected channel is turned off and the according over load flag CLn is
set. To turn on the channel again, this overload latch has to be reset by turning off the affected channel with either
the parallel input or SPI. In addition, the switch off delay time can be programmed by changing the slew rate
setting. If using the SPI interface and fault pin for diagnosis in case of current limit 2, the over load flag of the
affected channel is cleared by the rising edge of the CS signal after a successful SPI transmission when the IN
pin is low. A valid SPI cycle would not lead to a reset of the OVL flag of the affected channel during the IN-Pin is
high.
In both cases, the channel may shut down due to over temperature.