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Problem with TPS61085T + undervoltage lockout (UVLO)

Guillermo Maroto
Prodigy 150 points
Other Parts Discussed in Thread: TPA3111D1, TPS61085T, LM5122, TPS3895, TPS61085, TPS3898

Hello TI,

I'm developing a new product. I'm using TPA3111D1 audio amplifier and it needs 12V. So I have a Lipo single cell and I need Boost the voltage.

I've tested the TPS61085T but the problem is the Undervoltage lockout (2.6V).I've used 2 Sensing circuit :

-LMS33460MG . This one works but the problem is the noise at 3V.

-TPS3809K33. This one doesn't work.

But anyway the circuit of TPS61085T doesn't disconnect the load and the battery.

So I need a solution for the undervoltage lockout.

I have though in :

1.- LM5122

2.-Sensing circuit + solid state relay

What do you think? Whick one is better? Is there any solution for break the circuit at 3.0v?

Thank you very much

  • 0
    TI__Intellectual 1065 points

    5141.S181447223013082807270.pdf

    Hallo Guillermo,

    I have attached a sketch showing a possible solution to your problem (if I understood it correctly). The PMOS provides isolation from the battery and is controlled by a TPS3895 supply voltage supervisor (SVS). The SVS has an adjustable threshold, so you can set it to whatever you want. Note, that its output is active high - this is necessary to pull the PMOS gate low during normal operation. You can replace the PMOS with a relay if you want to, but that's probably not necessary with the likely power levels involved. The SVS also has an active-low enable input that can be used to turn the TPS61085 on and off; tie this pin to GND if you want the system to be permanently enabled as long as the battery voltage is above the SVS threshold.

    This is a proposal, and has not been tested (though it should work) - please make sure you read the IC data sheets thoroughly and follow any advice contained in them.

    Regards,

    Nigel

  • 0 in reply to Nigel
    TI__Intellectual 1065 points

    Oops - that should have been part number TPS3898 for the SVS.

  • 0 in reply to Nigel
    Prodigy 150 points

    Thank you :)

    I've checked and It works! That's exactly what I needed it