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TPS61023: STARTUP WITH CURRENT LIMITED SOURCE

sergio ramos
Prodigy 190 points
Part Number: TPS61023

Tool/software:

I'm working on a new design that will operate in an explosive atmosphere.  To meet the requirements, I must keep the maximum current into my device at 125mA MAX so I have a current limiting circuit between my battery and the input to the DC-DC. 

My question is will the TPS61023 startup with a 125mA current limited input source?  I am using this in a Vin=2.7-3.1V  and Vout=3.3V, 1Amp max for a a few mS.  The output current would only be approx 50mA until I transmit which wouldn't happen until the supply is fully up, voltage is correct, etc.  That is when I see normally 400mA and peaks of 1Amp for short durations. 

  • +1
    TI__Expert 8605 points

    Hi Ramos,

    TPS61023 has over 125mA current limit during start up. If your input is limited to 125mA, the TPS61023 still sinks over 125mA, so Vin will drop until triggering UVLO. Then TPS61023 stopped sinking current and Vin recovers. And then TPS61023 start again. This will repeat until after many start-ups the Vout finally reached its target.

    So the conclusion is, TPS61023 can start up with 125mA limit on its input. It just needs several times of reboot. Making Cin capacitance far over Cout will solve this issue.

    Best Regards,

    Travis