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TPS610985: What happens if VIN connected to gnd and SW is connected

mehmet can1
Prodigy 50 points
Part Number: TPS610985

What happens if VIN connected to gnd and SW is connected as in picture below;

What will be current consumptions in ACTIVE and low power mode ? Will Boost converter still be active ?

  • 0
    TI__Mastermind 46905 points

    Hi

    the device may be unable to active if the VIN is connected to GND. because the device need voltage at VIN pin to startup. but it is very strange configuration. it is out of the consideration during designing the IC.  why do you want to do that?

  • 0 in reply to Jasper Li
    Prodigy 50 points

    I am going to connect VIN to a mcu pin to try to stop boost converter even in active mode but i am not sure shunt fet always goes to off or it will be random ?

    And also i am not sure about current consumption in such state.

  • 0 in reply to mehmet can1
    TI__Mastermind 46905 points

    Hi 

    I'm afraid this doesn't work as the device doesn't have UVLO.

    if the input voltage is only less than 1.6V, how do you enable the IC again if the MCU disable it?

  • 0 in reply to Jasper Li
    Prodigy 50 points

    My mcu is self powered , (nrf52) it has it's own dc dc converter so i am going to use TPS610985 to power other peripherals, so i can enable the IC again. The problem is it's behavior. What will happen if i connect VIN pin to a mcu gpio and pull it to down ? Is there any possibility to that boost ctrl logic keeps shunt fet open ? 

  • 0 in reply to mehmet can1
    TI__Mastermind 46905 points

    Hi,

    the device can't be disable through VIn pin if the VOUT voltage is higher than typical 1.8V.

    you can add a MOSFET to disconnect the power supply or let the device on becaue of very small IQ. 

  • 0 in reply to Jasper Li
    Prodigy 50 points

    Thank you for your answer but  i really dont understand clearly , As i can see VIN is powering the boost converter . And you said that "the device can't be disable through VIn pin if the VOUT voltage is higher than typical 1.8V." Could you please explain little bit more , what is the logic behind of this  ? Is there any internal connection between VIN and VOUT? So if VOUT is higher than 1.8v , can it supply boost converter logic internally or what/how?

    Best regards.

  • 0 in reply to mehmet can1
    TI__Mastermind 46905 points

    Hi,

    the VIN pin is not the powering of the converter if the output voltage is higher than typical 1.8V. the internal circuit will be powered by the energy from VOUT. 

    you are right that there is internal circuit to select the VIN and VOUT source.