topic Re: max supply current in i.MX Processors

max supply current

sapirbuz — Sun, 19 Jun 2022 17:54:04 GMT

Hi,

can you please give me an example of how to calculate the maximum supply current? i didn't understand it from the picture below

NVCC_EMC(max curr)= 42*C*3.3*0.5F= 69.3CF

please help me estimate C and F

Re: max supply current

jingpan — Tue, 21 Jun 2022 06:05:56 GMT

Hi @sapirbuz ,

C is the whole capacitor load on the pin group. You can add them all according to your design.

F is signal frequency. For example, if the pin group is for SDRAM, then take the SDRAM working frequency.

Regards,

Jing

Re: max supply current

sapirbuz — Tue, 21 Jun 2022 07:18:51 GMT

This bank consists 42 pins, what freq should I choose?

what is the maximum freq?

Re: max supply current

jingpan — Thu, 23 Jun 2022 09:07:25 GMT

Hi @sapirbuz ,

This formula can help you to estimate maximum power consumption. It could not be very accurate. So, just use the highest frequency signal. For example, if the highest frequency signal in this group is a SPI, you can use the SPI bus frequency.

https://community.nxp.com/t5/i-MX-RT/RT1170-Max-Supply-Current-Calculation/td-p/1359582

Regards,

Jing

Re: max supply current

sapirbuz — Thu, 23 Jun 2022 14:54:17 GMT

Hi,

F= 60MHz (QSPI)

C= 4.9uF (according to eval board)

NVCC_EMC(max curr)= 42*C*3.3*0.5F= 69.3CF= 20374.2A?

what did i miss?

only for QSPI pins:

4*4.9u*3.3*0.5*60M= 1940A

it doesn't make sense

Re: max supply current

jingpan — Mon, 27 Jun 2022 09:38:49 GMT

Hi @sapirbuz ,

No, C couldn't be 4.9uF. It's impossible to push 42 4.9uF cap to 60M. Please refer to this post.

https://community.nxp.com/t5/i-MX-Processors/Question-i-MX6Solo-Max-supply-current/m-p/416445

Regards,

Jing

Re: max supply current

sapirbuz — Mon, 27 Jun 2022 10:23:11 GMT

thank you