topic Re: i.MX8 QXP maximum power consumption in i.MX Processors

i.MX8 QXP maximum power consumption

EAlepins — Tue, 03 Nov 2020 13:56:03 GMT

Hi,

We are currently evaluating the power consumption of the i.MX 8X for the subset of the SoC that we intend to use. From industrial datasheet IMX8QXPIEC Rev 0 (05/2020), §4.1.5 "Maximum Supply Currents":

1) VDD_A35 is shown at 2500 mA. Is this for the sum of all 4 cores? If so, how much is saved if some cores are turned off?

2) VDD_MAIN is shown at 5000 mA. It is not clear what parts of the SoC VDD_MAIN covers. §4.1.3 "Operating Ranges" gives some details: "Max freq.: HiFi4 DSP 640 MHz; Max freq.: M4 264 MHz; Max freq.: VPU 600 MHz". How is VDD_MAIN max supply current lowered if DSP and VPU are not used?

3) How is max supply current lowered if User Cortex-M4 is disabled?

4) How is max supply current lowered if Display Controller and Imaging Subsystem (MIPI DSI/LVDS/CSI, Parallel Capture, MJPEG) are disabled?

Thanks,

Étienne

Re: i.MX8 QXP maximum power consumption

jimmychan — Tue, 03 Nov 2020 17:55:06 GMT

We have an App. Note talk about power consumption measurement of i.MX8QXP. This may useful for you.

https://www.nxp.com.cn/docs/en/application-note/AN12338.pdf

For your reference, you can download all the documents of i.MX8QXP from here.

https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/i-mx-applications-processors/i-mx-8-processors/i-mx-8x-family-arm-cortex-a35-3d-graphics-4k-video-dsp-error-correcting-code-on-ddr:i.MX8X?tab=Documentation_Tab

Re: i.MX8 QXP maximum power consumption

EAlepins — Fri, 06 Nov 2020 20:08:31 GMT

Hi,

Unfortunately, the app note didn't answer any of those questions.

1) No use case only changes the number of active cores, so current/core cannot be isolated (too many variables are changing). Moreover, "CoreMark only" results are confusing: VCC_CPU draws 447 mA when 4 cores are active whereas datasheet rather shows about 2500 mA for VDD_A35... I understand the app note was done at room temperature, but were are talking about a ~5.5 factor...

2) No test case enables the DSP. Current per rail is not provided for VPU tests.

3) No test case disables the User Cortex-M4.

4) Maybe the app note answers: what are the supply voltages associated with the Display Controller and Imaging Subsystem (MIPI DSI/LVDS/CSI, Parallel Capture, MJPEG) ?

My concern is that if I simply multiply the supplies operating voltage ranges with the maximum currents found in the datasheet, the power consumption goes over 10W even without a GPU! I would like to know how much I can save by disabling the User M4 core, 1xA35 core, the Imaging subsystem, Display Controller, VPU, DSP and Audio DMA subsystem.

Thanks,

Étienne

Re: i.MX8 QXP maximum power consumption

EAlepins — Tue, 24 Nov 2020 14:17:07 GMT

Hi,

Any news?

Thanks.

Re: i.MX8 QXP maximum power consumption

jimmychan — Wed, 25 Nov 2020 15:56:29 GMT

I will check with internal if there is more power consumption information for your reference.

Re: i.MX8 QXP maximum power consumption

jimmychan — Mon, 30 Nov 2020 20:10:35 GMT

I got the reply from the internal team. Please find the answer from the attachment.

Have a nice day.

Re: i.MX8 QXP maximum power consumption

EAlepins — Mon, 30 Nov 2020 22:20:39 GMT

Hi,

Valuable information. However, the app note only provides power consumption at 25°C. I am surprised that the datasheet does not provide power consumption at higher temperatures (70 or 80 or 105 °C) as for other CPUs...

Étienne