use the EH pin of ST25DV for low-power MCU (stm32L4)

[Schuyler]

I want to use the EH pin of ST25DV to obtain energy through RF and power supply data transmission for low-power MCU (stm32L4). Can this scheme be realized? What should I do?

[Schuyler]

@JDEME 

Hi,

I used a jumper to connect pin EH to pin 16 of CN7, power light LD3 is on, so why did the MCU fail to start? If the energy is insufficient, then how can I use the EH energy to power the MCU?

[Schuyler]

If the EH pin current is too small to run the MCU, can I add a power module, such as LTC3108-1, BQ25570 or MAX17710, to transfer the small power energy emitted by the EH pin and provide stable power output to make the MCU run stabilities?

[Schuyler]

@JDEME 

Hi,

According to your description, what should I do to make the energy of EH pin drive stm32l476 properly? Can you give a reference diagram of the correct connection? I don't know exactly what to do.

Regards,

[Schuyler]

Hi，

@JDEME 

the EH is used the X-NUCLEO-NFC07A1 ST1connector jumper must be correctly set. But I don't know how to set it. Can I use the energy from the EH pin to power the L4 through the output pin of the LTC3588?

Regards,

[Schuyler]

Hi，@JDEME 

Do you want to connect the EH pin to PC5? I have disconnected USB POWER, how do I get power through the EH pin？

[Schuyler]

Hi, @Rene Lenerve 

According to what you said, I have finished programming to make LD2 flash, and then connected EH pin to 3.3V of CN6, and NFC07A1 and L4 used nucleo version, grounding and power supply were connected together, but I still did not drive L4 to complete the flashing test with the electric energy obtained through EH pin. What should I do? Here is my connection diagram.

[Schuyler]

Hi,

I have disconnected the ST-Link, then connected the EH pin to 3.3V, and the NUCLEO-L476RG power light was on, but the LD2 flashing light test with power programming did not succeed, indicating that L4 failed to power, why?

[JDEME]

Hello,

Did you cut the STlink ? Did you measure the current delivered by the EH pin  and  checked the balance between the MCU power consumption versus the power delivered by your phone  ?

BR

[Schuyler]

Hi @JDEME 

Yes, I'm not powering the ST-link, I want to power the MCU using the EH pin, but how can I reduce the power consumption? I am currently based on EH code in EN.X-Cub-NFC7, how to use the energy provided by the mobile phone to wake up the MCU?