Energy harvesting powers the MCU

[Schuyler]

I just read this document : https://www.st.com/content/dam/specialevents-assets/dc22/pdf/room-3-1-stdevcon22-session-nfc-for-wireless-charging.pdf 

there are two daughter boards, one based on ST25R3916 (NFC reader) and the other based on ST25DV-I2C (NFC dynamic tag). Both use STM32L476 as motherboard.However, the 3.3v power supply that I directly connected to L4 with EH energy in st25dv did not activate successfully. May I ask how to use NFC power supply to power MCU on the side of the label?

[Berenice BENVEGUDA]

Hi,

The document you just read is not related to energy harvesting but NFC wireless charging. It won't help you on energy harvesting topic.

Best Regards,

BB

[Schuyler]

Hi，

Therefore, does ST have relevant introduction about ST25's EH energy collection power supply MCU? I need to collect NFC energy to drive low-power MCU to collect signals, is there any reference document or guide?

[Schuyler]

Hi,

@Berenice BENVEGUDA   

 I have seen that ST25 Discovery MB1396 can use EH energy of ST25 to power L4, why can't I use NUCLEO of ST25DV? Is it possible to achieve wireless power supply for MCU?

[Rene Lenerve]

Hi @Schuyler ,

As already stated on that point, the Energy Harvesting from the ST25DV-I2C (and all tags providing Energy Harvesting) are dependent from the strength of the RF Field and the coupling of both antenna Reader and Tag.

So depending on the energy provided by the ST25DV you will need to adjust the configuration of the STM32L4 (clocks and IPs enabled) to be able to power it correctly.

It is possible to power the L4 with X-NUCLEO-NFC7 if you have correctly connected it and programmed a firmware using the lowest configuration as possible for your application in terms of current consumption.

Hope this can help you.

Kind Regards.

[Schuyler]

Hi @Rene Lenerve 

As I mentioned before, I use X-NUCLEO-NFC7 and L4. The EH example of the software package has set the energy of EH to active mode, but this energy is only enough for LED, not enough to drive NUCLEO-STM32L476RG. What should I do to power L4 through the energy obtained by NFC? Can you describe the code Settings in detail? But you mentioned earlier that EH only has 10 milliwatts of energy, can it drive L4 through EH?

Kind Regards.