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LM22678 for automotive applications

Gaston_Melo_Arg
Mastermind 7675 points
Other Parts Discussed in Thread: LM22678

Hi to all,

             I've designed a control system for automotive application. The Vin max is 3.6V and Imax=3A. I read the AN-1930 and the AN-1533 looking for information and I was wondering if someone has experience with the LM22678 for automotive applications (taking care of load-dump and Cold cranking).

Best regards

Gastón

  • 0
    TI__Prodigy 370 points

    Hi Gaston,

    The minimum input voltage for the LM22678 to worlk is 4.5V; it cannot support applications with 3.6V input supply.

    I have not used LM22678 in automotive application, but I am interested to work with you to find a TI part that fits your project. Would you mind to tell me more about your application such as the output voltage and input voltage range?

    Regards,

    Jimmy

  • 0
    TI__Genius 10115 points

    Hi Gaston,

    Sorry for the delay in response.  What type of information are you looking for specifically? Are you looking for a reference design, or help diagnosing a power schematic for suitability?

     

    Regards,

    Marc

     

  • 0 in reply to Marc Davis-Marsh
    Mastermind 7675 points

    Hi to all,

                   I need to use the car (or truck) supply system. Reading the AN1930 and AN1533 (about load dump and cold crank condictions) I want to know if this is the right choice for the application. The electronics require an input of 3.6V input and 5A max (this is a tracking system). I want to avoid any chance of transients voltage that could damage the electronics.

    Do I require two TVS and a current limiter to avoid any kind of problem or  is there one IC that could replace the two TVS and the current limiter?

    I have my doubts regarding the current limiter because the current requirements of the electronics (more than 3A----the pcb space is a real problem here).

    any help will be appreciated.

    Regards

    Gaston

  • 0
    TI__Prodigy 370 points

    Hi Gaston,

    Each vehicle manufacturer has its load dump and cold crank transient voltage specification. It is necessary to provide an overvoltage protection circuit to prevent the LM22678 from exposing to transient voltage above 42V max. and a blocking diode in series with the input rail to protect the VIN pin from reverse battery.  

    Attached is the OVP circuit modified from the one shown in AN1533. The circuit trips at 40V, turning Q1 OFF to disconnect the Cload (which is the input to4555.LM22678 Load dump OVP.docx the LM22678) from VIN. DIN, Q1 and Q2 have to be selected according to transient voltage and the load current. Refer to AN1533 for the details of the circuit operation.

    Jimmy – TI - SVA