TLE8110EE Datasheet, PDF (35/72 Pages) Infineon Technologies AG – Smart Multichannel Low Side Switch with Parallel Control and SPI Interface

FLEX
Smart Multi-Channel Switch
Protection Functions
10
Protection Functions
The device provides embedded protective functions. Integrated protection functions are designed to prevent IC
destruction under fault conditions described in this Document. Fault conditions are considered “outside” the
normal operating range. Protection functions are not designed for continuous repetitive operation.
There is an over load and over temperature protection implemented in the TLE8110EE.
If a protection function becomes active during the write cycle of Diagnosis Information into the Diagnosis Register,
the information is latched and stored into the diagnosis register after the write process.
In order to achieve a maximum protection, the affected channel with over current or over temperature is switched
off. The device can be configured via serial communication interface in three ways in order to react on this fault
condition:
• after switching off, turning on again after a delay time: In case of over temperature, when the temperature has
decreased below the temperature shut down threshold. In case of over-current, the affected channel is turning
on after a delay time until the over temperature protection is activated.
• after switching off, turning on again the affected channel with the next parallel or serial control command.
• Default Setting: after switching off latching the condition and remain off until the Diagnosis Register is cleared
via serial control. In this case, the internal Diagnosis Bits for Over Temperature and Over Current are cleared
with the rising edge of S_CS
For the failure condition of Reverse Currents, the device contains a “Reverse Current Protection Comparator”
[RCP]. This RCP can optionally be activated by setting the DEVS.RCP Bit.
In case the comparator is activated, it detects a reverse current and switches ON the related output channel. The
channel is kept ON up to a reverse current channel dependent threshold I_{RCP_off}. This threshold is defined by
regulators target value to keep the output voltage at >/~-0.3V. If the current exceeds a defined value, the
comparator switches OFF and other protection functions are protecting the circuit against reverse current. That
means that at higher currents / or in case RCP is de-activated / not activated, the reverse current is flowing through
the body diode of the DMOS. In that case, the voltage drops to typically -0.6V according the voltage of the body
diode. In case the comparator threshold has been exceeded and the RCP has been switched OFF, the functions
remains OFF until the reverse current arrives back to zero reverse current. Only then, the comparator can be
activated again after a delay time t_{RCP_on_delay}.
This function reduces the un-wanted influence of a reverse current to the analogue part of the circuit (such as the
diagnosis). For more details about the functionality, see Figure 21 and Figure 22 and concerning the settings and
the related registers, refer to Chapter “Control of the Device”.
Figure 19 gives an overview about the protective functions.
Serial
control
RCP
Ref.
Logic
-300mV
Ctrl.
temperature
sensor
T
gate
control
short circuit
detection
OUTx
Figure 19 Block Diagram Protection Functions
Data Sheet
35
Block _diag_Protection.vsd
Rev. 1.0, 2009-06-15