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TMDSHVMTRPFCKIT: Hardware fix

Andy Yoon
Prodigy 20 points
Part Number: TMDSHVMTRPFCKIT
Other Parts Discussed in Thread: CONTROLSUITE

Hello all,

Few days in, and I've done it. I've burnt off a chip (more like the chip exploded).

I was following the [controlSUITE\development_kits\HVMotorCtrl+PfcKit_v2.1\HVACI_Scalar] example project, and got to page19, where I was probing DAC-1 through 4 with an oscilloscope. 

I had one end touching DAC-4 and saw the correct waveform, but with an offset. When I touched the ground clip of the probe to the GND pins right next to the [MAIN]-J4, [M4] portion exploded with a bright light. 

Here's what I did:

and here's what happened

Was the GND not a ground?

Does TI do repairs?

Thanks.

  • 0
    TI__Guru* 81640 points

    Andy,

    I can fwd this to the kit expert in C2000 to see if there are any tips/advise on what may have happened here.  Unfortunately TI does not perform repairs on our kits, this would be something that if possible would need to be addressed by you by replacing components if possible.  Else you would need to buy a new EVM from the TI store if that is not possible.

    Best,

    Matthew

  • 0 in reply to MatthewPate
    TI__Guru** 116320 points

    Andy,

    Andy Yoon said:
    When I touched the ground clip of the probe to the GND pins right next to the [MAIN]-J4, [M4] portion exploded with a bright light. 

    Did you use an isolation power supply or transformer for the oscilloscope when you connect the oscilloscope ground to the EVM?

     You may take a look at the guide (HVMotorCtrl+PFCKit_HowToRunGuide.pdf) in the folder of controlSUITE

    C:\ti\controlSUITE\development_kits\HVMotorCtrl+PfcKit_v2.1\~Docs

    You may find the waring note as below in the guide.

    Note that the ground planes of both the power domains are the same, hence proper isolation requirements must be met before connecting any test equipment with the board

  • 0 in reply to MatthewPate
    Prodigy 20 points

    Hi Matthew. Thank you for your reply. I think the copper traces themselves are fried, so I may have to get another one...

  • 0 in reply to Yanming Luo
    Prodigy 20 points

    Thanks for your reply.

    I did not use an isolation power supply or transformer for the oscilloscope... If the ground planes of both power domains are the same, I don't understand why the GND pin on the EVM and the oscilloscope gnd were different.

    If I use an isolated probe instead of a grounded probe, I should be okay right? I just want to make sure I dont burn another EVM :P

  • +1 in reply to Andy Yoon
    TI__Guru** 116320 points

    If you have a look at the guides for high voltage kit in the folder of controlSUITE as mentioned above, you may find the notes below. The high voltage kit is a floating ground design.

    • The kit can accept power from the AC Mains/wall power supply, the board only uses the live and the neutral line from the wall supply, the protective earth is unconnected (floating).

    • The AC rectifier generates the DC voltage the ground of which is floating from the protective earth ground. Hence appropriate caution must be taken while connecting scopes and other test equipment to the board.

    Warning:

    It is the user’s responsibility to confirm that the voltages are identified and understood, prior to energizing the board and or simulation. When energized, the EVM or components connected to the EVM should not be touched.
    Isolation transformers must be used when connecting grounded equipment to the EVM.

    Most oscilloscopes have their “signal common” terminal connected to the protective grounding system, commonly referred to as “earth” ground. This is done so that all signals applied to or supplied from the oscilloscope have a common connection point. This is usually the oscilloscope chassis and is held at (or very near to) zero volts by virtue of the third-wire ground in the power cord for AC-powered equipment.  Which means that measurements almost always should be made with respect to the earth ground, which in turn restrains a standard oscilloscope from measuring potential differences between two points, neither of which is at ground. Unwanted ground current may add bothersome hum and ground loops that will damage the measured board or oscilloscope.

    Sorry, you have to order a new high voltage kit if you can't repair it by yourself.

    Please go through the guides carefully and follow the guide to use the high voltage kit. You have to use a differential probe or isolation power supply/transformer with oscilloscope to measure any signals on the high voltage kit.