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ADM1272 Peak Power register

Hi Expert

We saw the description of peak power in the ADM1272 datasheet. (0XDA)

I can understand that Peak Power comes from voltage and current, but there are still a few questions that need your assistance.

1. What time period is this based on? Does this include all the values for a complete startup and shutdown?

2. Is V/I the averaged value? Or is it calculated by raw data from each VI/I conversion?

Looking forward to receiving your feedback. thanks

  • Hi Chester,

    1) The ADC runs independently of the hotswap FET control circuit, so it does sample during startup and shutdown. In general the current during startup and shutdown should be small compared to operating current, so should not tigger an update to the PEAK_PIN register during those times.

    2) Power average is calculated separately from V, I averaging. Power averaging uses individual ADC samples (not averaged V, I samples). These are multiplied together prior to power averaging.

    Thanks!

      Nathan

  • Hi Nathan

    1)So can I say that  the peak power is record high when ADM1272 work and it is "not average" value?

    2) got it and thank you.

  • The ADC takes V and I samples one at a time and feeds them into two different averaging calculators. The power average is selected by the PMON_CONFIG register, bits 13:11. As you can see, the power (V*I) average is independent of the V and I average (which is selected by PMON_CONFIG[10:8]). You can select power averaging from 1 sample (no averaging) to 128 samples. Also note that the ADC samples voltage then current in sequence, unless you select the PMON_CONFIG[14] bit to enable SIMULTANEOUS sampling of V and I so the multiplication represents a precise moment in time. Simultaneous sampling stores one of the samples while the ADC is converting the other, so there is a slight accuracy penalty. selecting simultaneous sampling does not increase the ADC conversion rate.