iMX 6UL Power Consumption Measurement

[jonathanli]

I'm measuring the voltage drop off R705 (SPF-29090_C schematics) to see the power consumption off the coin-cell battery.  I turn on the board with DC adapter and coin cell both plugged in and then after bootup, I disconnect the DC adapter. The  measurement over the 1K resistor at R705 was 115mV which is higher than we'd like. 

From AN5170 - App Note - I.MX 6Ul Power Consumption Measurement 4.4 Notes.  They suggested switching boot_mode[1:0] to 2b'00 after system boot up.  I did this and the measurement off of R705 is now 85mV.

It also suggested to remove U2101 and leave the Tamper Pins floating.  I do both of these things and no change.

I also tried removing R761 to see if it would make any difference.  The measure off of R705 is now 56mV.  Is it possible to tie this pin to DCDC_3v3 instead?

The first thing on the note section is:  1. POR_B pin setting: GPBIT[1:0] set to 2b’01;

Can anyone please explain what this means?  I'm hoping this is the key to saving a bit more power?

Thanks in advance,

Jon

[jakubkuzilek]

Hello

We have same problem with current consumption from coin cell. I measured almost same value 49uA to i.mx6ul. Tamper pins are floating and all other snvs domain pins are disconnected from peripherals when pcb is not powered. PF3000 is capable to deliver only 65uA to battery and current drawn by core+pmic+perif=55-57uA and it is not acceptable. Before first design we expected current 22uA measured in AN5170. For us it is really critical problem because we need to use security features, tampers and rtc.

Can anybody help with this issue?

Thanks

[Yuri]

Hello,

   To reduce consumption "Boot From Fuses" should be used in order to

remove the external resistors on boot pins. Also, please use i.MX6 UL

part of TO1.1.

  As for "POR_B pin setting: GPBIT[1:0" - this relates to IOMUX settings,

IOMUXC_SW_PAD_CTL_PAD_POR_B. You may try internal pull up,

open drain disabled.

.

Have a great day,
Yuri

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