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TPS546B24A: TPS546B24A Vout command transfer fomula question

Danny Chin
Prodigy 80 points
Part Number: TPS546B24A

Hi,

For TPS546B24A, we found Vout command 0x0222 and get output voltage =1.066406V. Could you advis how to let 0x0222 transfer to 1.066406V? Do you have transfer fomula?

Thanks,

  • +1
    TI__Guru 50285 points

     

    In PMBus, the VOUT_COMMAND data format is defined by the VOUT_MODE command.  The default value of VOUT_MODE for the TPS546B24A is 0x97 this means

    Relative Data Format, so commands which use the relative format like VOUT_MARGIN_HIGH, VOUT_MARGIN_LOW, VOUT_OV_WARN_LIMIT, VOUT_OV_FAULT_LIMIT, VOUT_UV_WARN_LIMIT and VOUT_UV_FAULT_LIMIT are provided as a factor of VOUT rather than a direct voltage

    Linear 16 Format, so the 16-bits of the VOUT command values are the mantissa using a power-of-2 exponent.

    Exponent -9, so the voltage associated with each LSB of VOUT_COMMAND is 2^-9V or about 1.95mV 

    To convert the hex value to voltage:

    1) Convert the Hex Value to Decimal  0x0222 = 546d LSB

    2) Multiple the LSB by the LSB weight: 546d x 2^-9V = 1.066406V