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LP87563-Q1: Load current measurement using LP8756x

Part Number: LP87563-Q1

I am trying to do load current measurement from LP87563 PMIC through I2C. Would like to know ,after clearing the interrupt bit I_LOAD_READY in register INT_TOP1, how long it will take for the measured value to appear in I_LOAD_1 and I_LOAD_2 registers

  • Hi Aruna,

    From reading section Buck Converter Load-Current Measurement, my interpretation is that the measured value would be available in I_LOAD_1 and I_LOAD_2 registers before the interrupt is generated, so if the interrupt has appeared then it is already ready.

    Note that you would need to be sure the interrupt is clear before you write to the LOAD_CURRENT_BUCK_SELECT[1:0] bits in SEL_I_LOAD register. At that point, the maximum time is 50 us for a conversion and once completed the interrupt should appear.

    If there is follow up, our device experts in EU time zone will continue assisting you.

  • Hi Kevin

    For me the interrupt bit I_LOAD_READY is not getting set after 50us. In my implementation I am polling INT_TOP1 register and it takes more than 20ms for the I_LOAD_READY bit to get set. I am reading PMIC register using bitbang I2C.

    I write 0x1 to INT_TOP1 register to clear the interrupt before writing to SEL_I_LOAD register. An d then I poll for the interrupt bit.

  • Hi Aruna,

    Have you checked I_LOAD_READY_MASK (register 0x21 bit 0) is set "0"?

    I checked behavior on EVM and when a new load current measurement is triggered by writing "0" to register 0x25 (read BUCK0 current) the nINT-pin is pulled low before 50µs limit. So that means that load current result should be available on registers 0x26 and 0x27.

    Have you took oscilloscope shots after 0x25 wrote to "0" and when nINT goes low? And how polling interrupt register 0x1A matches in time?

  • Hi Jari

    This was the issue. The I_LOAD_READY_MASK was not getting set. 

    Corrected it.