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LP87561-Q1: AVS control

Ioan Marusca
Prodigy 250 points
Part Number: LP87561-Q1

Hi TI support,

Does LP87561 support AVS controlled by the load (a CPU) using a 200 Ohms inserted between feedback pin FB_B0 and load ? 

Regards

  • +1
    TI__Expert 6410 points

    Hi Ioan,

    No. AVS is intended to be done over I2C by writing corresponding BUCK VOUT register.

    Br, Jari

  • 0
    TI__Expert 4985 points

    Hi Ioan,

    LP87561-Q1 supports AVS through I2C writes. The MCU must write to the output voltage registers BUCKx_VSET on the PMIC. The PMIC will then scale up or down to that new target voltage following the defined slew rate setting.

    In addition, LP87561-Q1 supports roof/floor voltage control where the output voltage can be switched between two different output voltages using one of the pins.

    BR,

    Samuli

  • 0 in reply to Samuli Piispanen
    Prodigy 250 points

    I would call the method you suggested as DVS. I understand that DVS is the TI recommended way to control the voltage but is not applicable to the ASIC/CPU I'm using. 

    The ASIC/CPU I'm using has proprietary (and undocumented) method ,"hardcoded" in silicon, where it wants to do analog trimming/adjusting in the feedback loop to change the nominal voltage of 0.8V by +/- 0.2V as it sees it fit for the operating conditions.

    Does LP87561-Q1 allow this "analog" trimming of the feedback loop ?

    Regards

  • 0 in reply to Ioan Marusca
    TI__Expert 4985 points

    Hi Ioan,

    Unfortunately this is not possible. The previously described methods are the only supported ways to scale the output voltage.

    BR,

    Samuli