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  1. #1
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    What is the effect of 100 microseconds(us) transient in a automobile battery?

    A typical embedded system, let's say Transmission or Power Train Electronic Control Unit (ECU) is powered by automobile Battery.

    Battery voltage is at 12 Volts. If the battery voltage drops to 0 Volts in 5 us and stays at 0 V for 100 us, then rises back to 12V in 5 us, what impact will this have on Microcontroller memories, different microcontrollers inputs like Analog, Digital, PWM, etc. And different outputs like Digital, PWM etc.

    Will the contents of I/O and memories like SRAM, Program Flash, Data Flash change due to this transient?

    The microcontroller on the ECU is Infineon Aurix TX29x.

    - - - Updated - - -

    Correction! The Microcontroller is Infineon Aurix Tricore TC29x

    •   Alt10th January 2017, 23:36

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    Re: What is the effect of 100 microseconds(us) transient in a automobile battery?

    Hi,

    A rather hypothetical question. But I can't see any use behind such a question.

    How do you decide to bring a healthy car battery down to 0V and then back to 12V within microseconds?

    A microcontroller doesn't run on 12V. It runs on 5V, 3.3V or even less. So it needs some power supply, maybe a SMPS.

    Every microcontroller datasheet specifies the operation voltage range, for memories there is a "data retention voltage".
    But as said before this has nothing to do with battery voltage.

    ******
    You compare the wrong voltages.
    An example with temperature instead of voltage:
    If you want to boil an egg.....then the temperature of the water is what matters, not the temperature of the gas flame.

    Klaus



    •   Alt11th January 2017, 01:16

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    Re: What is the effect of 100 microseconds(us) transient in a automobile battery?

    Automotive EMC standards like ISO 7637 specify considerably stronger disturbances than you presume. If you want your design to work in the real automotive world, provide filters that are capable to deal with the ISO 6737 test pulses.



    •   Alt11th January 2017, 08:58

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  4. #4
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    Re: What is the effect of 100 microseconds(us) transient in a automobile battery?

    I think he is talking about short circuit for a period of 100 us like some Mosfets used in electric vehicles shorting for 100 us.



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    Re: What is the effect of 100 microseconds(us) transient in a automobile battery?

    >> How do you decide to bring a healthy car battery down to 0V and then back to 12V within microseconds?
    This is proprietary information.

    I'll check the memories data retention voltage.



    •   Alt11th January 2017, 16:40

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  6. #6
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    Re: What is the effect of 100 microseconds(us) transient in a automobile battery?

    Even if the system is going to to 0v and then back to 12v within microseconds (with a propreitory way) ,
    the regulator supply filter can be sized for taking this sudden shock for few microseconds.



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