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LM5025A latch mode OCP

K.Hamamoto
Guru 12155 points

Hi

Our customer would like to set the latch mode (OCP) with this device.

We understand this device has two type of OCP. (Cycle by cycle=CS1 and Hiccup mode=CS2)

They already use this device with hiccup mode at the current model. However they would like to use this device with latch mode for next model.

Do you have any idea to set this device to the latch mode by a minimal external component?

I wonder that it is possible to put the resistor in parallel on Css for setting to latch mode.

Regards,

Koji Hamamoto

  • 0
    Guru 12155 points
    Hi

    Do you have any idea for the latch mode setting?

    Regards,
    Koji Hamamoto
  • 0 in reply to K.Hamamoto
    Guru 12155 points
    Hi

    Let me add the explanation to previous post.

    The SS source current is changed from 1uA to 20uA when the SS pin voltage reaches 1V.

    Thus, it might be possible to set latch mode(at only OCP) if the resistor in parallel on Css is set the SS pin voltage to be less than 1V during overcurrent restart(source current 1uA).

    Is my understanding correct?

    Regards,
    Koji Hamamoto
  • 0 in reply to K.Hamamoto
    TI__Mastermind 31580 points
    Hi Hamamoto-san,

    Pulling the SS pin to 0V externally wll disable the switching.

    The customer will have to add an external circuit that provides the latching function to keep the SS pin pulled low once the OCP fault has been cleared.

    Is there a bias rail/vcc rail present to power the latch circuit during the OCP event?

    Regards

    Peter
  • 0 in reply to Peter Meaney
    Guru 12155 points
    Hi Peter-san

    Thank you for your kindly support.

    There is no bias supply during the OCP event. Also the customer understand that is possible to latch the OCP if they uses any circuit for this.

    My point is the simple way to latch the OCP event. Is my idea incorrect? (To put one resistor in parallel on Css)

    Regards,
    Koji Hamamoto
  • 0 in reply to K.Hamamoto
    TI__Mastermind 31580 points
    Hi Koji-san,

    Yes pulling the SS pin to ground through a resistor will work providing the voltage drop resistor and series switch is very low.

    Regards

    Peter