AnsweredAssumed Answered

Poor iMX7D power performance

Question asked by Jacob Postman on Aug 17, 2016
Latest reply on Jan 4, 2017 by Evgeny Erlihman
Branched to a new discussion

I am doing a power evaluation on a modified imx7d sabre board and am seeing higher than expected power consumption from the imx7D, both when sitting awake and idle and during suspend to memory.

 

When ttymxc0 is not set as a wakeup source, the VDD_3V3 current in suspend increases dramatically, while the current on VDD_SOC decreases.

I expect that the imx7d should be able to reach much better power numbers.

 

The best I can guess right now is that the clock domain configuration is not working as intended. Is this a known issue? Am I barking up the wrong tree and is there anything else in my configuration that I should be looking for?

---

Setup:

Most peripheral components on the imx7d sabre board have been removed and each of the following rails is provided and measured externally.

Only USB OTG, DEBUG UART-USB and a SD card are attached to the board.

I am using a yocto 2.0 machine-test image rootfs with an independently built kernel and dts based from the bsp 4.1.15_1.0.0_ga tree.

All items in imx7d-sdb.dts except for i2c3, sdma, uart1, usbotg1, and usbotg2 are removed or disabled.

 

Power:

Awake and idle:

VDD_ARM  7.3 mA,   1V     7.3 mW

VDD_SOC 154 mA,   1V     154 mW

VDD_1V8  12.5 mA, 1.8V   22.5 mW

VDD_3V3  15 mA,   3.3V   49.5 mW

VSNVS   <1 mA,   3V     <3 mW

VLPSR   0.05 mA, 1.8V   0.09 mW

 

Suspend to mem with ttymxc0 set as wakeup source:

VDD_ARM 0.6 mA,   1V     0.6 mW

VDD_SOC 13 mA,   1V     14.3 mW    < Why is this so high?

VDD_1V8  5 mA,     1.8V   9 mW

VDD_3V3  5 mA,     3.3V   16.5 mW

VSNVS   <1 mA,   3V     <3 mW

VLPSR   .05mA,   1.8V   0.09 mW

 

Suspend to mem without ttymxc0 wakeup source:

VDD_ARM 0.6 mA,   1V     0.6 mW

VDD_SOC 1.3 mA,   1V     1.3 mW

VDD_1V8  5 mA,     1.8V   9 mW

VDD_3V3  61 mA,   3.3V   201.3 mW < Why is this so high?

VSNVS   <1 mA,    3V     <3 mW

VLPSR   .05mA,   1.8V   0.09 mW


Jacob

Outcomes