Powering the STM32L476RG board from the EH pin of the ST25DV

How can I power the STM32L476RG board via the EH pin of the ST25DV? Is there a module for this?

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Best answer by Peter BENSCH

Yes, you can supply an STM32L476RG via the EH pin of an ST25DV if:

you have observed the note on pin V_EH in the data sheet: This analogue output pin is used to deliver the analogue voltage V_EH available when the Energy harvesting mode is enabled and if the RF field strength is sufficient. [...] Energy harvesting voltage output is not regulated.
The last sentence indicates that you connect a voltage regulator downstream, like e.g. in the STEVAL-SMARTAG2, which can generate the VCC for the STM32L476. It makes sense for this voltage to be as low as possible (in STEVAL-SMARTAG2 = 1.9V) so that even weaker NFC fields are able to supply the STM32. Of course, you must design the entire board for ultra-low power so that other consumers do not cause the voltage to collapse. The STM32L476 program must also be carefully optimised for minimum power consumption.

Hope that helps?

Regards
/Peter

Technical Moderator

Yes, you can supply an STM32L476RG via the EH pin of an ST25DV if:

you have observed the note on pin V_EH in the data sheet: This analogue output pin is used to deliver the analogue voltage V_EH available when the Energy harvesting mode is enabled and if the RF field strength is sufficient. [...] Energy harvesting voltage output is not regulated.
The last sentence indicates that you connect a voltage regulator downstream, like e.g. in the STEVAL-SMARTAG2, which can generate the VCC for the STM32L476. It makes sense for this voltage to be as low as possible (in STEVAL-SMARTAG2 = 1.9V) so that even weaker NFC fields are able to supply the STM32. Of course, you must design the entire board for ultra-low power so that other consumers do not cause the voltage to collapse. The STM32L476 program must also be carefully optimised for minimum power consumption.

Hope that helps?

Regards
/Peter

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