• Resolved

TPS40400: TPS40400 and Power Good

Part Number: TPS40400

Hi TI,

we have been looking into TPS40400 to supply 1.00V core voltage for a CPU. We think the current can be up to 10A, therefore we will use the voltage sense function that this part have.This CPU will handle the I2C and PMBus for TPS40400.

We would like to use the POWER GOOD from the TPS40400 to be one of the signals that control the RESET for the CPU, but this looks impossible since the default value setting for POWER_GOOD_ON  is 1.104V. We would get 1.00V out because of the resistor setting, but POWER GOOD would never be true.

Can you confirm this? Do you know any work-around other than skipping the POWER GOOD signal?

regards

Trond Inge Wang

  • Trond,
    You can use the power good. When you program set the Vout scale loop to 0.6 since your output is 1V. The default value of Power good on is 92%. What this means is that when Vout reaches 0.92V power good is ON.
    From datasheet page 42:
    The parameter passed with this command is always the lower
    threshold (less than the nominal output) and is mapped to the closest supported percentages of the nominal
    output voltage inTable 36 (Use the Low thresholds from the table)
    Default of power good OFF is 90%, so once power Good in ON, then the voltage needs to drop to 0.9V for the power good to be OFF.

    Power good function is a window comparator, so if the output voltage exceeds 110% then power good will be OFF

    Regards,
    Mathew