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TPS2112: TPS2112 Quiescent Currents

George Sephton1
Prodigy 20 points
Part Number: TPS2112
Other Parts Discussed in Thread: LM66100

Hi,

I have the following circuit:

With 3V from VCELL going into IN2 and 0V on USB_VBUS_3V3, the TPS2112 is adding an extra 35-40uA onto the total current draw.

Is there any way to reduce this down to around 2 or 3 uA?

Cheers

  • 0
    TI__Genius 13650 points

    Hi George,

    The TPS2112 will always consume some amount of current to operate through either channel. This current is found to be 55uA typical with an input supply of 5.5V. With an input of 3V you will see a decrease in current to consumption to operate which is what I believe is the 35-40uA you are seeing. Since this is the current the device is consuming to operate there is no way of reducing this current to 2-3uA.

    Is the 35-40uA of current the overall current consumption from the switch you are observing or is it 35-40uA on top of the 55uA typical current consumption of the switch?

    Best regards,

    Andy Robles

  • 0 in reply to Andy Robles
    Prodigy 20 points

    Hi Andy,

    Thanks for the response. The 35-40uA is the current draw from the TPS2112 alone so I guess this just isn't suitable for my application.

    Do you have any alternate solutions for switching between a battery source and a USB source where current consumption is in the region of a few uA? My battery is a coin cell so a small current draw is crucial. I need a switching circuit so that when the user connects a USB cable, the power is pulled from USB in order to conserve battery life, but when the USB cable is removed, the power will revert to being drawn from the cell.

    Many thanks,

    George.

  • 0 in reply to George Sephton1
    TI__Mastermind 28695 points

    Hello George,

    A better lower cost (and lower power) solution here would be to use the LM66100 in a dual ORing configuration such as the one outlined in the datasheet:

    The downside here is that you wouldn't have any diagnostics or protections such as undervoltage lockout that you would with a power mux, however it would be lower cost, better power consumption, provide reverse current protection, and give a way to dual your power sources.