OPTIREG™ SBC TLE9274QXV33
Supervision functions
13.8
Thermal protection
Three independent and different thermal protection features are implemented in the SBC according to the
system impact:
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Individual thermal shutdown of specific blocks
Temperature prewarning of buck regulator
SBC thermal shutdown due to buck regulator overtemperature
13.8.1
Individual thermal shutdown
As a first-level protection measure, the output stages VCC2, CAN and LINx are independently switched OFF
when the respective block reaches the temperature threshold TjTSD1. Then the TSD1 bit is set. This bit can only
be cleared via SPI once the overtemperature is not present anymore. Regardless of the SBC mode, the thermal
shutdown protection is only active when the respective block is ON.
The different modules behave as follows:
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•
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VCC2: It is switched OFF and the control bits VCC2_ON are cleared. The status bit VCC2_OT is set. Once the
over temperature condition is not present anymore, the VCC2 must be reconfigured by SPI. The thermal
protection in VCC2 is available only in SBC Normal mode or SBC Stop mode with watchdog activated
CAN: The transmitter is disabled and stays in CAN Normal mode acting like CAN Receive-Only mode. The
status bits CAN_FAIL = 01B are set. Once the overtemperature condition is not present anymore, the CAN
transmitter is automatically switched on
LIN1, LIN2, LIN3, LIN4: The transmitter is disabled and stays in LIN Normal mode acting like LIN Receive-
Only mode. The respective status bits LINx_FAIL are set to 01B. Once the overtemperature condition is not
present anymore, the LIN transmitter is automatically switched on
Note: The diagnosis bits are not cleared automatically and have to be cleared via SPI once the overtemperature
condition is not present anymore.
13.8.2
Temperature prewarning
As a next level of thermal protection, a temperature prewarning is implemented if the buck regulator reaches
the temperature prewarning threshold TjPW. The status bit TPW is set. This bit can only be cleared via SPI once
the overtemperature is not present anymore. Regardless of the SBC mode the temperature prewarning is
active only if the buck converter is ON.
13.8.3
SBC thermal shutdown
As a highest level of thermal protection, a temperature shutdown of the SBC occurs if the buck regulator
reaches the thermal shutdown temperature threshold TjTSD2. The temperature protection is available only in
case that the buck regulator works in PWM modulation. The thermal protection is not available if the buck
regulator works in PFM mode.
Once a TSD2 event is detected, SBC Fail-Safe mode is entered for at least tTSD2. The default wake sources (CAN,
LINx, WK pin) are enabled together with the fail-safe outputs.
When a TSD2 event is detected, the status bit TSD2 is set. This bit can only be cleared via SPI in SBC Normal
mode once the overtemperature is not present anymore. Regardless of the SBC mode the thermal shutdown
is only active if the buck converter is ON.
Datasheet
93
Rev.2.0
2022-05-06
INFINEON [ Infineon ]
