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TPS544B20: about READ_VOUT

Yasushi Fujiwara
Genius 12725 points
Part Number: TPS544B20

Hello Experts,

I have a question about READ_VOUT as follows. Would you answer them?
1. Customer has been experience that READ_VOUT returned "0x0001(0.001953125V)". If overload(load transition) or over current are occurred, READ_VOUT will return such number? Or other things would be considered?
2. In case of CNTL="L", what does READ_VOUT be going to return?

Best Regards<
Fujiwara

  • 0
    TI__Guru 56985 points

    Yasushi Fujiwara,

    The TPS544x20 family of PMBus compatible integrated FET converters run their output voltage monitoring feature whether the output voltage is enabled or not.  The TPS544x20 devices monitor the voltage on the VOUTS+  

    If the output is experiencing a fault condition, such as OV FAULT, UV FAULT or OC Fault, the output voltage will be reported as sensed by the VOUTS+ pin and could be as low as 0x00 00 (0V) depending on the sensing offset errors, averaging and average output voltage.

    A single Analog to Digital Converter (ADC) is shared across all of the measurements and time-division multiplexed to monitor each input (Voltage, Temperature, and Current) so in a fault condition where the output voltage has widely spaced short ramps with a near 0V value across most of the period, it is not unusual for the ADC to report very near 0V.

    The ADC continually monitors the VOUTS+ voltage, even  if conversion is disabled, and will report a voltage on the output even if switching is disabled, if an external leakage or source is providing a voltage.

  • 0 in reply to Peter James Miller
    TI__Genius 12725 points

    Hi Miller,

    Thank you for reply. In addition, would you tell about what is resolution of ADC when ADC measure VOUTS+? Is 12bits?

    Best Regards,
    Fujiwara

  • 0 in reply to Yasushi Fujiwara
    TI__Guru 56985 points

    The internal Analog to Digital Converter (ADC) is a 12-bit dual slope integrating ADC with a 1ms integration period.

    The output voltage has an 8:1 input divider so that the 0 to 5.5V output voltage range can be brought down to 1V input range of the ADC, so the LSB of the ADC is 2^-9V or 1.953mV.

  • 0 in reply to Peter James Miller
    TI__Genius 12725 points

    Hi, 

    Would you tell the INL/DNL of ADC? I cannot find these spec in the datasheet. Customer would like to know accuracy of READ_VOUT value.

    Best Regards,
    Fujiwara

  • 0 in reply to Yasushi Fujiwara
    TI__Guru 56985 points

    the accuracy of READ_VOUT is specified in the datasheet at +/- 2%