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TPS1H100-Q1: [TPS1H100BQPWPRQ1] Inquiries related to 'GND Short Detection'

MJ Jeon
Genius 5240 points
Part Number: TPS1H100-Q1

Hi, TI Support Team

I have received inquiries regarding diagnostics of TPS1H100-Q1 products from customers.

Please refer to the attached materials for detailed explanations and inquiries about the content.

Inquiries are written in blue letters on the attached sheet.

TI社 High Side SW TPS1H100B_circuit inquiry_211210.xlsx

Thanks.

Regards,

MJ

  • 0
    TI__Genius 16390 points

    Hi MJ,

    Could you double check with the customer that for the measurement, did they measure against DGND or RGND? During the short-to-GND event, DGND might be shifted due to large current. The real CL voltage will be relative to RGND.

    Regards,

    Yichi

  • 0
    Prodigy 100 points

    Hello, I'm Hyun Jun, Cho

    Does RGND mean IC GND? (Pin No.2)
    I tried shorting OUTPUT to the corresponding GND, but Vcs is output as 5.7V.

    The Vcs Max value of the IC is specified in the datasheet as 4.9V.

    The actual measured value and the spec do not match.

    Please check this part.

  • 0 in reply to Hyun Jun Cho
    TI__Genius 16390 points

    Hi Hyun Jun,

    Yes, did you measure the Vcs value against IC_GND? There might be a shift in voltage between the IC_GND and the GND.

    Regards,

    Yichi

  • 0 in reply to Yichi Zhang.
    Prodigy 100 points

    Hello, Yichi

    Yes, I shorted OUTPUT to IC GND.

    When shorted, Vcs voltage was 5.7V.

    As I said above, it does not match the Vcs,h specifications of the TPS1H100. please check.

    Best regards

  • 0 in reply to Hyun Jun Cho
    TI__Genius 16390 points

    Hi Hyun Jun,

    Could you check if my understanding is correct? From the schematics you attached, there's DGND (GND) and RGND (IC_GND). When you short the output to the IC_GND, how did you measure the CS voltage? Is it from the read out at EXT_AMP_DIAG_ADC? If that's the case, then the voltage you're reading is referring to DGND. Could you manually probe the voltage using oscilloscope with positive at CS pin and negative at RGND (IC_GND)?

    Am I understanding the situation correctly or could you elaborate on your measurement of the CS pin voltage? Thank you! 

    Regards,

    Yichi

  • 0 in reply to Yichi Zhang.
    Prodigy 100 points

    Hello, Yichi

    I will answer your questions as follows.

    1. TI Question : 

    From the schematics you attached, there's DGND (GND) and RGND (IC_GND).

    When you short the output to the IC_GND, how did you measure the CS voltage?

    Is it from the read out at EXT_AMP_DIAG_ADC?

    If that's the case, then the voltage you're reading is referring to DGND.

    1-1. Answer : 

    The measured point is the CS Pin (Pin No.14).
    (I measured the only CS Pin voltage because the voltage value of EXT_AMP_DIAG_ADC eventually follows the voltage of the CS Pin.)
    And the CS voltage was measured refer to DGND.

    (

    2. TI Question

    Could you manually probe the voltage using oscilloscope with positive at CS pin and negative at RGND (IC_GND)?

    Am I understanding the situation correctly or could you elaborate on your measurement of the CS pin voltage? Thank you!

    2-1. Answer : 

    Are you talking about taking the IC GND as the reference and measuring the CS voltage?
    When IC GND is the reference, the CS Pin voltage is as follows.

    1. Short circuit to IC GND: 4.77V
    2. Short circuit to DGND: 4.77V

    When measuring CS voltage, is the reference RGND? Are you DGND?
    The Max 4.9V specified in the datasheet is based on what GND?

  • 0 in reply to Hyun Jun Cho
    TI__Genius 16390 points

    Hi Hyun Jun,

    The datasheet value should be referring to the IC_GND (DGND). If the voltage over 5V is a concern, then it would be good to use a Zener diode at CS pin to clamp the voltage to be under 5V to not damage the microcontroller pins.

    Regards,

    Yichi