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TPS1H200EVM: test 2.5A application fail

Adrian Ymeraj
Expert 3810 points

Part Number: TPS1H200EVM

Hello team,

my customer tested the high side switch at 2.5A and it failed. The application is for a BA board. The set up for the 2.5A test was The measurements were performed with a an input voltage of 26.5V, a capacitive load of 470uF and a resistive load to get a load current of 2.5A.

The mentioned device has although passed the 0.4A which the customer would like to test with lower cost devices too.

The current limits were set to 0.74A for the 0.4A application (2700R) and 2.94A for the 2.5A application (680R) and a 330nF cap was connected on the delay pin.

Now in our portfolio we have TPS1H100 and the TPS1H00 devices; do you think these could be more suitable for such testing?

Do you feel the 2.5A test was performed well with the TPS1H200 device?

Thank you for your support.

Best regards,

Adrian

  • 0
    TI__Expert 3575 points

    Hi Adrian, 

    In order to help you understand what is going on I will need a bit more information here. 

     1- Can you define the failure of the device. What kind of failure are you referring?  

     2- What is the ambient temperature at which this device was tested?  I am requesting for this because the device could be entering a thermal shut down.

     3- Can you share waveforms of the Fault, Vout, Vin, IN, and the output current? I am trying to see the conditions at which the device is operating in order to see if any fault is being reported here.  

     4- I think you are using our EVM, but can you confirm this? 

    Once I have these answers I will be able to start the debugging of the issue. Thank you very much for reaching out.  

  • 0 in reply to Francisco Lauzurique
    TI__Expert 3810 points

    Hi Francisco,

    The device is not able to power-on properly with an output current of 2.5A and an additional capacitive load of 470uF.

    Please find below the measured waveforms.

    The measurements were performed in the office, so ambient temperature is about 22°C.

    The device is toggling the output, so thermal shutdown or internal current limit is triggering.

     

    CH1: Output Voltage

    CH2: Output current

    CH3: Input Voltage

    And yes the customer is using the EVM available via ti.com.

    Thanks in advance for your support.

    Regards,

    Adrian

  • 0 in reply to Adrian Ymeraj
    TI__Expert 3575 points

    Hi Adrian, 

    I am working in your question. I will have an update for you tomorrow. Thank you very much for reaching out again. 

  • 0 in reply to Francisco Lauzurique
    TI__Expert 3575 points

    Hi Adrian, 

    I believe that the problem here is that the latch time triggering is happening before the transition from Thermal Swing to TABS (see image two) and the current is too narrow for the current limit to trigger. According to my calculations here your total delay time is of about 103ms. To be more sure about this, can you include the measurements of the voltage on delay pin. This could tell us what is actually happening here.   

  • 0 in reply to Francisco Lauzurique
    TI__Expert 3810 points

    Hello Francisco,

    I think the problem is the thermal swing protection.

    As you can see, the output voltage doesn’t rise to the level of the input voltage because of the protection triggering.

    What protection functions are switched off by pulling DIAG_EN low?

     

    I will you provide the additional requested measurements asap.

     

    Best regards,

    Adrian

  • 0 in reply to Adrian Ymeraj
    TI__Expert 3575 points

    Hi Adrian, 

    I agree, the issue here might be coming from the trying to trigger current limit while on thermal swing. When DIAG_EN is low, when protections will trigger, but no report will take place. Current limit and thermal protections will trigger without report.