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LM74900Q1EVM: about SLEEP_OV connected to VOUT or C issue

Lawrence He
Genius 3105 points
Part Number: LM74900Q1EVM

Hi, Support Team

Could you explain about "SLEEP_OV connected to Vout and C" ?
What is the difference between to Vout and C?
and What`s conditions or application to choice SLEEP_OV connected to Vout or C?

if any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence

  • 0
    TI__Guru 57737 points

    Hi Lawrence,

    While in SLEEP mode, if there is an input over voltage condition you can choose to clamp the output voltage to 21.3V or cut off the output when input voltage reaches above 21.3V.

    Connecting SLEEP_OV pin to VS or C pin sets the device in overvoltage cut-off functionality where as connecting the SLEEP_OV pin to OUT pin sets the device in overvoltage clamp functionality.

    In Clamp operation there will be power dissipation = [(Vin-Vout) x FET Ron] in the internal FET because of which there will be temperature rise in the FET. If the IC internal junction temperature goes above 155C, the internal FET is turned OFF due to thermal protection.  

  • 0
    Prodigy 50 points

    Hi Support team,

    How about SLEEP_OV connect an external zener diode application?  Any example can show how to increasing threshold and connection?  Thanks.

     

  • 0 in reply to Paul Tseng
    TI__Guru 57737 points

    Hi Paul,

    We do not have a test waveform to show this operation but you can connect a zener as shown in the image and increase the SLEEP_OV threshold to 21.3V + Zener voltage. 

  • 0 in reply to Praveen GD
    Prodigy 50 points

    Hi Praveen,

    Did the current threshold follow zener diode rating, too?  Thanks.

  • 0 in reply to Paul Tseng
    TI__Guru 57737 points

    Hi Paul,

    No, The Over current threshold and short circuit threshold will not be changed due to the addition of zener on the SLEEP_OV pin.