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BQ27520-G4: Can I adjust the current sample rate or trigger a current sample?

Ben Renneberg
Prodigy 130 points
Part Number: BQ27520-G4

I believe samples (current, voltage, temperature) are taken on a 1 second timer and the timing has no relation to when I do I2C transactions. Is that true?

I'm pulse-charging a battery with about 10uS pulses with some variable dead-time between. I would like to see average current as well as high current in my application. Can I increase or adjust the sample frequency somehow, or can I trigger samples using an external trigger?

My pulse charger also runs on a 1 second timescale, so even lowering the frequency slightly might be better than matching the 1 second timescale, as I might end up always sampling between pulses if they happen to be synchronized.

  • 0
    TI__Guru* 76230 points
    Hi Ben
    The ADC for the device is a delta sigma integrating ADC, so although current is reported every 1s, the guage will be able to handle the pulses. You can't increase the 1second timescale. Make Sure to set the slpwkchg bit to compensate for missed passed charge data when the gauge is in sleep.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 130 points
    It looks like slpwkchg is set to 1 by default in the datasheet. Is the ADC running off of the 8.389MHz or 32.768kHz oscillator? Do you expect it to make a difference in measurement accuracy if I keep it awake, or in SNOOZE mode instead of letting it sleep?
  • 0 in reply to Ben Renneberg
    TI__Guru* 76230 points
    I don't expect a significant difference in accuracy since the gauge wakes once every 20s to take measurements. The device only goes into sleep if the current measured is less than the sleep current... There are two clocks which the device uses, the HFO and LFO. In snooze both are on while in sleep the HFO is off which allows for reduced power consumption of the gauge.