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TPS22945: higher OC limit alternative

Part Number: TPS22945

Hi,

Our customer is looking for a OC protection device with the following requirements:

  • Input range from 1.9V to 3V
  • Extremely low Iq (less than 1uA target) this is part of the always powered domain and must consume little power.
  • Over current threshold approx. 500mA

Is there a device for these requirements? 

-Kelvin

  • Kelvin, 

    We don't have a single device that can meet all this requirements.

    Honestly, the closest match we have is probably TPS22945 which you mentioned.

    As far as the power consumption, it is important to consider the contributon of load switch RON to the system power diss. 

    With some of our low IQ devices, the RON is 1-2 orders of magnitude higher. For an always-on application, this has a MUCH larger power dissipation effect than quiescent current

    Ex: 0.5ohm*0.5A= 250mW -> RON losses

          100e-6uA*3V=0.3mW -> Iq losses. 

    Because of this tradeoff with RON, Low Iq load switch are actually much better for normally-off applications rather than always on. , like for DC charger supply for example on a low-power device.  Because the Quiescent current is not even close to being the dominant power dissipation source. 

    I may even recommend you to look at Ideal diode or eFuse for this case, which also have such source. 

    Is the customer open to this?

    Best

    Dimitri

  • Dimitri,

    The customer is open.  However, I coudn't find a reasonable low voltage (1.9V) efuse or ideal diode for this application.  Do you have one in mind?

    -Kelvin

  • Kelvin,

    https://www.ti.com/power-management/power-switches/ideal-diodes-oring-controllers/products.html#p238min=0.48;2

    Please take a look here, we have several options for ideal diodes which can meet your customer's needs. 

    Unfortunately we don't have ideal diode with current limit function which can support your low voltage function. 

    If your customer must have adjustable current limit TPS22945/6 load switch is probably your best bet.

    As i said before, I dont think we have a switch which can meet all the needs. 

    If you have further question on selection please reply please let me know

    Best

    DImitri