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Original question:

LM74670-Q1: TIDA-00858 for anti-surge

LM74670-Q1: How does the device fail?

Stephen Felkel
Prodigy 40 points
Part Number: LM74670-Q1

Hi all,

I have a customer who is looking at using this device for one of his projects. He is monitoring an 8 to 20 V input but because the power supply is subjected to harsh weather conditions he is concerned about performance during surge conditions. They are using external circuitry to handle surges but he wants to make sure in the event of a failure, the rectifier does not draw current in order to protect devices at the load. Has there been any testing to see how the LM74670 fails and can we guarantee him that it will fail as an open?

Thanks!

Stephen

  • 0
    TI__Genius 16305 points

    Hello 

    During surge, if the input to the rectifier rises quickly and fast, there would current flowing through the rectifier diode to charge the output capacitor.

    If this current is beyond the maximum rating of MOSFET, the MOSFET would damage.

    Do see a chance of absolute maximum rating of anode to cathode or cathode to anode exceeding?


    Regards,

    Kari.

  • 0 in reply to Karikalan Selvaraj
    TI__Prodigy 40 points

    Hi Kari, 

    Thanks for the response. With the design there is a chance of the anode to cathode or cathode to anode exceeding the maximum rating. Based on the customer explanation, they expect to see 100V surges with inrush currents up to 0.5 A for 5 ms which is why the customer is concerned in the event of a failure, how the diode bridge will react.

    Regards,

    Stephen