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TPS1H200A-Q1: Using as overcurrent/short circuit disconnect switch following a boost converter - how to connect?

hamasaki1818
Intellectual 370 points
Part Number: TPS1H200A-Q1

Hiya,

I'm considering to use TPS1H200A-Q1 as an overcurrent switch after a boost DC converter for 16V output.

The connections are as follows:

Boost DC/DC (part # not important, it is not TI part) -> TPS1H200A -> user-accessible DC output connector.

Boost is enabled via EN pin which is normally pulled down, making the circuit off. let's call that net BOOST_EN.

The 16V device(s) I'm powering with the output are spec'd to draw no more than 250mA and I'd like to current limit this output to around 300-400mA max, and (if possible) disable boost when such overcurrent event is detected, perhaps by pulling down the BOOST_EN net.

I have 5V, 3.3V rails available on the board.

Looking at Figure 32 in datasheet (typical application circuit) VS is the input, OUT is the output, but VS also provides power for the rest of the ICs functions.

If I use the FAULT flag to turn off boost regulator, what happens once TPS loses the power? FAULT will go high again since its open-drain, and pulled up, right?

So what would be the correct way to handle something like this (I don't have an external MCU here to do some smarts like monitoring fault and turning off BOOST_EN based on that).

  • 0
    TI__Mastermind 32650 points

    Hello,

    When you reset the part, the fault will shift high as it is an open-drain circuit. 

    A few questions:

    1. What is your reasoning on placing the switch after the boost converter?

    2. Do you plan on using the other features on the part such as the DELAY pin?

    I ask this because placing the high side switch before the boost converter would result in a straightforward application of using the FAULT pin and EN pin to run BOOST_EN.

  • 0 in reply to Shreyas Dmello
    Intellectual 370 points

    > 1. What is your reasoning on placing the switch after the boost converter?

    None whatsoever.

    > 2. Do you plan on using the other features on the part such as the DELAY pin?

    Nope, just turn off boost on overcurrent/short circuit.

    > I ask this because placing the high side switch before the boost converter would result in a straightforward application of using the FAULT pin and EN pin to run BOOST_EN.

    That makes so much sense, thank you. That's what I will do.