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Dual TPS84610 shutdown control

Other Parts Discussed in Thread: TPS84610

Hello all contributors,

I need to produce two power supplies with one (1.8V) which needs to always stay upper than {the other one (1.2V) minus 200mV}, until both of them goes below 300mV. This, even in case of uncontrolled primary power shutdown.

I thought about using two TPS84610, one used in tracking mode, as I'll use this component for other supplies on the board. Fortunately, I tried this with EVMs:  This works well at startup, but when removing the input power, tracking doesn't work anymore, there is a trip point where the 2 output crosses over.This can be seen even both supplies unloaded.

What do you suggest to overcome this issue?



  • Yes the tracking function lo longer works when the input voltage falls below teh UVLO threshold and the device turns off.  You could do something exotic, such as sensing the input voltage upstream then providing enough local input capacitance to hold the second TPS84610 on until the output voltage can be discharged under tracking control.  I think the simplest approach is to use a Schottkey diode between the two rails to limit the voltage differences.

  • Hello John,

    Thank you for your answer.  I'd rather avoid trying something exotic. Simpler solutions often leads to faster and more reliable results, so the diode is definitely what I'm considering.

    I'm assuming that the the first supply (the tracked one) will withstand the reverse current  from the second supply through the diode when she is conducting; but as the  UVLO threshold could differ between each component, I should select a diode supporting at least the max current output of the TPS, isn't it?