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LMR16030: schematic review

Intellectual 1660 points

Replies: 1

Views: 42

Part Number: LMR16030

Dear expert,

My customer is using LMR16030, VDD_SYS_4.2V is system power for load and BATTERY_3.7~4.2V is the battery. Now they need to maintain the PGOOD function even if Vin is off, so wondering if adding the diode (in the left upper corner) can keep the PGOOD function(1.6~1.95V output) from BATTERY_3.7~4.2V battery voltage when Vin is off. 

From my understanding, after Vin is off, VDD_SYS_4.2V will always be higher than Vin, therefore the upper FET will be off so FB voltage is low and PGOOD function can't perform. Am I right? If so, please share your suggestion about how to achieve the PGOOD function even if Vin is off, thanks!

  • Hi Minqi,


    Yes, i believe you are correct as long as the VIN (pin) 2 voltage is in the range of 1.6 ~ 1.95V, the PGOOD reading will be valid.

    If the FB voltage is within range then the PGOOD will be high and when the FB voltage is low (output is shutdown) then the PGOOD reading will be low.

    Looking at the schematic, once your VIN_12_C is OFF, then your PGOOD should be reading low siince the diode D2 will be reverse biased. 


    Thanks

    -Arief

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