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PTD08D210W: Part too hot

Lucy Fanelli76
Prodigy 60 points
Part Number: PTD08D210W
Other Parts Discussed in Thread: UCD9248,

I am working with a board that uses two UCD9248's to control four PTD08D210W's. I did not design the board and there are a lot of things I don't know about the parts, but there are 2 big issues that I am wondering how to resolve:

1. The parts get very hot when sourcing relatively small amounts of current. Is there any setting I can change that will make them heat up less?
2. The fusion software makes reference to the ability to calibrate the parts for voltage offset, but when I try to find calibration in the software I always fail. Is there a way to voltage calibrate these devices? There are instructions in fusion about which menu to select to find the calibration but there is no calibration option there.
 
Thanks,
Lucy

  • 0
    TI__Expert 8130 points

    Hi Lucy,

    1. If you take a look at the Power Dissipation figures on the data sheet you will find that the device at no load dissipates about 500mW. Keep in mind, that this device has a dual output, therefore, about 1 Watt is dissipated at no load.
    2. I am not familiar with the Fusion Software. I reached out to the UCD9248 team (separate team from Modules), but unfortunately, the original design and applications team for UCD9248 are no longer available. I can only point you to the Output Voltage Adjustment section in the datasheet.

    Regards,
    Alejandro

  • 0 in reply to iAlejandro
    Prodigy 60 points

    Thanks Alejandro,

    I can see there are programmable cal registers in the programming guide, but unfortunately the only way I have of communicating with the UCD part right now is through Fusion which seems to be missing its cal section. I wonder if there is a calibration ability in older versions of the software, since the software makes reference to it (it's just not in the menu options when you try to find it).

    One other issue is that the current measurement shown in the Fusion software is way off-the part is reporting about 10x the current that is actually being drawn as far as I can tell. I tested this by using an external bench supply to provide power rather than the TI regulators and saw that the current reported by the bench supply was much lower.  Right now, the passive components in the voltage feedback loop on the board are far off from their ideal values as given by the fusion software. I wonder if reworking them will fix some of these issues.

    -Lucy

  • 0 in reply to Lucy Fanelli76
    TI__Mastermind 24075 points

    Hi Lucy, 

    The Vout cal offset is in Fusion->Configure->Other Config tab. 

    For the current measurement, can you check if IOUT_CAL_GAIN value in Fusion->Configure->Other Config tab is correct?

    Thanks

    Qian