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LM74700-Q1: Short Circuit on Gate PIN

stefan wolter
Prodigy 30 points
Part Number: LM74700-Q1
Other Parts Discussed in Thread: LM74800-Q1, LM74502-Q1

Tool/software:

Hello TI Team

In my application I need to quickly disable the external FET in case of overload. Can I use an external bipolar transistor to short circuit the LM74700-Q1 GATE PIN to Ground (over an 10 Ohm Resistor) in case overload is detected? Will this damage the device?

Or alternatively how much delay I have form setting the EN to zero until FET OFF? This must be under 10us.

Thanks

Stefan Wolter

  • 0
    TI__Mastermind 46280 points

    HI Stefan,

    I am unsure if LM74700-Q1 is the right choice here. I am assuming you are looking for a load disconnect switch, LM74700-Q1 will still have a path from body diode.

    Please consider LM74800-Q1 or LM74502-Q1

    Regards,

    Shiven Dhir

  • 0 in reply to Shiven Dhir
    Prodigy 30 points

    Hello Shiven

    I have a back to back configuration and am planing to use 2X LM74700 because I need the ideal diode in both directions. I want to use external circuitry to override the gate voltages. I need 4 states: All ON, diode direction A, diode direction B and all OFF.

    Will I damage the device if I use a transistors to short the gate signals?

    Here a simplified diagram

  • 0 in reply to stefan wolter
    TI__Mastermind 46280 points

    Hi Stefan,

    Grounding the GATE pin is not recommended. If you want faster turn-on, better to short it to ANODE as the GATE is driven with respect to ANODE pin and not ground.

    Next, I am not sure if 2 back-to-back LM74700-Q1 are going to work as reverse current blocking can NOT be disabled. 

    Regards,

    Shiven Dhir