LTM4625 overcurrent mode

Hi Team,

LTM4625: How should an over protection look like: would it be a hickup? a latch? for how long?

Same with overtemp and over voltage.

thanks for your quick reply,

Itay

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  • 0
    •  Analog Employees 
    on Dec 2, 2019 6:38 PM

    Hi Itayelbit, 

    The LTM4625 protects from over-current condition by fold-back current protection instead of latch-off or hiccup. For fold-back current protection if the load current exceeds the current limit of the part, the Vout and FB voltages will drop. If the FB voltage drops below 0.6V the current limit is reduced linearly, down to 40% of the max current limit at 0V FB voltage. 

    For Vout over-voltage protection, the controller turns on bottom fet to bring Vout back down to regulation if the FB pin voltage is higher than 10% (typical) of nominal (ie 0.6V).

    For Vin over-voltage protection, the controller will shut off both fets if Vin is above 23.5V, and turn them on gain when Vin falls below 21.5V.

    For over-temperature protection the controller will shut off both fets when the junction temperature reaches 160C, and then them turn on-again when the junction temp falls back down below 145C.

    Thanks. 

Reply
  • 0
    •  Analog Employees 
    on Dec 2, 2019 6:38 PM

    Hi Itayelbit, 

    The LTM4625 protects from over-current condition by fold-back current protection instead of latch-off or hiccup. For fold-back current protection if the load current exceeds the current limit of the part, the Vout and FB voltages will drop. If the FB voltage drops below 0.6V the current limit is reduced linearly, down to 40% of the max current limit at 0V FB voltage. 

    For Vout over-voltage protection, the controller turns on bottom fet to bring Vout back down to regulation if the FB pin voltage is higher than 10% (typical) of nominal (ie 0.6V).

    For Vin over-voltage protection, the controller will shut off both fets if Vin is above 23.5V, and turn them on gain when Vin falls below 21.5V.

    For over-temperature protection the controller will shut off both fets when the junction temperature reaches 160C, and then them turn on-again when the junction temp falls back down below 145C.

    Thanks. 

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