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AXEL Lite SOM simplifies this task by embedding all the needed circuitry. The following picture shows a simplified block diagram of PSU/voltage monitoring circuitry:
[[File:AXEL Lite-power-sequence.png | 800pxthumb|center|600px | Power sequence]]
The PSU is composed of two main blocks:
VDD_SOM denotes the power rail used to power AXEL Lite SoM.
[[File:AXEL Lite-power-good.png|thumb|center|600px|Power good]]
===Real-time clock (RTC) powering===
Real-time clock is integrated in iMX6 processor. As such, it belongs to SNVS power domain. This domain, in turn, is powered by PMIC, via PMIC_VSNSV rail (see also [[Power_(AxelLite)|this page]]). PMIC integrates a sort of switch. When 3V3VIN voltage is applied, this is used to power SNVS domain. Otherwise energy is drawn from coin cell battery - if any - connected to PMIC_LICELL (for more details please refer to <ref name="MMPF0100">NXP, ''MMPF0100 - PF0100 Data sheet: Advance Information''</ref>).
[[File:Axellite-rtc.png|thumb|center|600px|Simplified block diagram of Axel Lite RTC powering scheme]]
It is worth remembering that 3.0V lithium batteries are supported and that PMIC_VSNSV voltage range is 2.4 - 3.6V. When [[FAQs_(Axel)#Q:_How_to_enter_RTC_mode.3F|Axel Lite enters RTC mode]] and 3V3VIN voltage is removed, typical current absorption from PMIC_LICELL pin is about 135uA. This value is '''relatively high''' with respect to the typical lithium coin cell battery capacity (10 - 50mAh). It is recommended that system integrator verify that expected battery lifetime satisfies system requirement. If not, the use of an external low-power RTC device should be considered.
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[[Category:AXEL Lite]]