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11uA to 30 uA low power pulses at 4ms intervals.

SDK16

S132

nrf52832

SES / Windows 10

After much searching this site and the web in general I'm reaching out for support.

While in low-power mode I'm seeing a pulse between 11uA and 30 uA every 4ms.  I'm pretty much down in the nA range  between pulses. 

I've verified it's not environmental as another device (legacy) appears to be clean.  Hardware is identical - so I'm thinking it's in my firmware,.

GPIOS are turned off as is the ADC.

Wondering if anyone else has seen this - what peripheral on the device would operate at this interval while in low power.  

Thanks in advance for any advice,

Peter

Parents Reply Children
  • The regulator is in refresh mode independent of LDO or DCDC mode

  • This is unexpected behaviour; I thought the automatic refresh mode was conditional on external components and therefore could be disabled (or rather not enabled before enabling the softdevice). The external components are optional:

    Automatic switching between LDO and DC/DC regulator based on load to maximize efficiency
    Note: Two additional external passive components are required to use the DC/DC regulator

    Breaking execution with and without DCDCEN enabled shows that the softdevice does not enable the DC-DC converter; does this imply a pulsed LDO? How does that reduce power consumption?

  • Refresh mode is not the same as DCDC. The refresh mode is only in use when the device is on it's lowest power state and barely "kept alive". The way it works is that you have a capacitor that is charged quickly with a short pulse. The regulator senses the voltage on the cap and gives another pulse when the voltage drops below the threshold. This gives quite a lot of ripple on the regulator output but that doesn't matter as none of the power critical parts are on anyway. So you sacrifice ripple and load regulation for better efficiency.

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