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PTN04050A: Functional definition of this part, not stated!

groger57
Prodigy 250 points

Part Number: PTN04050A

Hello:

Hoping someone at TI can help me out with this mystery part. It's absolutely not clear anywhere what this module is - boost, buck, or both. The datasheet, nor anywhere on the TI website does it use that term boost to describe it. Yet, it seems it might be, as the maximum input is 7V, and documentation states it can be adjusted anywhere in the stated output range of -3.3V to -15V. Seems a bit of a stretch, to get 1A when the input is 3V and the output is -15! That would mean the input is somewhere around 5.5A, assuming 90% efficiency!

Can someone please advise on this part? 

Thanks!

Gary

  • 0
    Prodigy 250 points

    Hi,

    Ok, I think I found at least part of the answer. Page 3 of the data sheet has a table showing efficiency:

    RSET=1.96kΩ,VO=–12V,IO=0.5A

    so I guess that makes sense if maximum power is 6W !!

  • 0 in reply to groger57
    TI__Guru*** 142860 points

    Hi Gary,

    On the product folder and in the D/S, this device is referred to as a 'positive to negative converter'.  Does it help if I add the word 'voltage' in there?

    positive to negative voltage converter

    Today, this type of converter would be called an 'inverting buck-boost converter', which converts a positive DC voltage to a negative DC voltage, which can be either above or below (in terms of its absolute value) the input voltage.  Here is a detailed paper on the topology: http://www.ti.com/lit/an/slva059b/slva059b.pdf

    What power requirements do you need to meet?

  • 0 in reply to Chris Glaser
    Prodigy 250 points

    Chris,

    After a good read of the datasheet, I get it.

    So the term "boost" is redundant when describing an inverting converter? For example, the PTN04050C has the word "boost" lavished everywhere, but the PTN05050A has no trace of the word anywhere in any document. Just threw me off, that's all.

    Thanks for the doc reference.

    My power requirements can be met with the PTN05050A at 6W. To handle dynamic peaks, I'd like to have a bit more stored energy/capacitance than the maximum of 200uF, as the load is about 60cm to 100cm away. By the datasheet, looks a bit unlikely!

    Gary

  • 0 in reply to groger57
    TI__Guru*** 142860 points

    Hi Gary,

    Actually, the PTN04050C is a completely difference module with a completely different function--it is a boost converter.  This takes a lower DC voltage and makes a higher DC voltage.  Both voltages are positive.

    What is your input voltage source and its voltage range?  What output voltage do you need?  How much output current or power do you need?

  • 0 in reply to Chris Glaser
    Prodigy 250 points

    Hi:

    IN: 3.2V min, 4.8V max

    Out: +12V, 350mA, AND -12V, +350mA

    Looks like PTN04050A and C will do the job, since they are boost/inverters.

    Gary

  • 0 in reply to groger57
    TI__Guru*** 142860 points

    That should work great.  Your power needs line up with those devices pretty well.