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Original question:

TMS570LS0432: about RTI register

TMS570LS3137: ABOUT TPS65381

whong zhao
Genius 4190 points

Part Number: TMS570LS3137

Hello

 Team

 I want  to use the tps65381 control the important power supply.this system is SIL4.

 I see the  paper. this ENDRV io of tps65381 can export the High and low level.when  CPU communicate with 65381 is not normal, TPS65381 can output  low level .

Does it guarantee such a function, is it reliable?If 65381 has a problem, can it guarantee that it export a low level?

 

  • 0
    TI__Guru**** 201456 points

    Hi Whong,

    In safety-related application, it is strongly recommended to use a external watchdog monitors the correct operation of the MCU. The watchdog in TPS65381 can do this job. This watchdog requires specific messages (Q&A mode) from the MCU in specific time intervals to detect correct operation of the MCU. You are correct, when the watchdog detects incorrect operation of the MCU, the device pulls the ENDRV pin low.

    This ENDRV pin can be used in the application as a control signal to deactivate the power output stages, for example a motor driver, in case of incorrect operation of the MCU. 

    You need to check if ENDRV pin works properly in TPS65381 diagnostic stage by injecting a ESM error to TPS65381 ERROR/WDI pin. TMS570 MCU can detect the ENDRV level using one GIO pin.

  • 0 in reply to QJ Wang
    Genius 4190 points

    Hello

     when the watchdog detects incorrect operation of the MCU, the device pulls the ENDRV pin low.

    Has this realization passed the security certification? Although it can be tested, how to ensure its reliability?

    Means If The TPS65381 have  failure, he can the output ENDRV low level 

  • +1 in reply to whong zhao
    TI__Guru**** 201456 points

    During the normal operation, ENDRV internal switch is off and a high voltage is seen on this pin due to internal pull up resistor. Whenever there is a issue with the device which requires ENDRV to be driven low, internal switch is turned on and this pin is pulled low with the internal switch (max rdson of this switch is 40 ohm). Whenever ENDRV pin is low, it is an indication of system not ready or there is some failure and safety function (for example motor driver or external power stage) can be shutdown.

    As I mentioned before, ENDRV pin is the "safing" enable output of the TPS65381 and may need to be monitored by a TMS570 GIO input pin.

    Any condition that causes the TPS65381 to go to SAFE state will make ENDRV go low. 

  • 0 in reply to QJ Wang
    Genius 4190 points

    Thank you

    dose the ENDRV pin function have Safety analysis report？