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TPS61220 - Output Short to GND

Poh Leong Ng
Intellectual 745 points
Other Parts Discussed in Thread: TPS61220, TPS61070, TPS61251

Can TPS61220 recover after the output pin is shorted to GND? Would the short circuit damage the Vout pin and render the IC useless?

For the application, there is a possibility of the Vout pin hitting GND potential.

  • 0
    TI__Guru**** 150930 points

    Most likely, a short on the output would damage the IC, as the IC cannot control the current that would flow through the body diode which conducts from L to Vout.  From the datasheet page 11, "This diode cannot be turned off, so the current finally is only limited by the remaining DC resistances."

    Whether it would damage the IC would depend on the amount of current that flowed and for how long.  If, for example, the TPS61220 were supplied from a battery or solar cell that could only provide, for example, 1 mA into a short circuit, then the IC would most likely not be damaged.

    An IC that can control the current during a short circuit is the TPS61070.

  • 0 in reply to Chris Glaser
    Intellectual 745 points

    Hi Chris,

    Thanks for the reply. I read through the datasheet and found Figure 22 on the short circuit current. If my battery input voltage is 3.7V and I short the output pin to GND, the pin will still be delivering about 100mA. This is still not so good. Is it possible to disconnect the input totally from the output during short circuit?

    Does TPS61251 offers better short circuit protection? The datasheet isn't clear on that.  

  • 0 in reply to Poh Leong Ng
    TI__Guru**** 150930 points

    I assume that you are referring to figure 22 in the TPS61070 datasheet.

    Yes, most ICs, including the TPS61251, will still operate into a short on the output.  How can the IC tell that it is a short or simply start-up (when the output voltage begins from 0 anyways)? 

    100 mA is a fairly safe level of current in my opinion.  Since it is a short, that is 100 mA @ less than a Volt, so very little power being sent into the short.

    You could use some logic or an SVS monitoring the output to disable the TPS61070 if a short is detected.  When disabled, the output is disconnected from the input, unlike in the TPS61220.

    Other options are a fuse or a hot swap IC which would latch off if an OC event were detected.  You can post to the power interface forum to find one of those.