diegopm
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CM4 power consumption

Fri Nov 06, 2020 2:56 pm

Hi,

What is the maximum and typical power consumption for CM4 module?

In the datasheet says Iload = 1.4A so 7W.
These 7W includes the 600ma 3.3 and 1.8 outputs?

Thanks.

dp11
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Re: CM4 power consumption

Fri Nov 06, 2020 3:01 pm

Power consumption greatly depends on your application.

The figures given don't include any external loads

diegopm
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Re: CM4 power consumption

Mon Nov 09, 2020 9:47 am

Hi,

I can consider 1.4A@5V at maximum current consumption?

Do you have the current consumption at 5V with Linux running and HDMI displaying, without any special task? it would be very useful for me, becuase I need to validate my carrier board for moving from CM3 to CM4.

Thanks, BR

dp11
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Re: CM4 power consumption

Mon Nov 09, 2020 9:54 am

I think the simplest option would be to measure the current in the same situation for a Pi4, CM4 is typically slightly lower power consumption. The difficulty is that "without any special task" the clocks have almost certainly been turned down to reduce the power consumption.

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Gavinmc42
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Re: CM4 power consumption

Mon Nov 09, 2020 10:53 am

I read it was about 9W max.
1.8amps?
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diegopm
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Re: CM4 power consumption

Mon Nov 09, 2020 11:12 am

It would be useful for me to have an answer to:
In equal tasks, who consumes more CM3 or CM4?
If the consumption of CM4 is higher, in what percentage roughly are we talking about?

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Gavinmc42
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Re: CM4 power consumption

Tue Nov 10, 2020 1:22 am

Apples and Oranges.
What software are you running?

The Pi4 can be clocked faster, does the job then shuts down.
From what I gather the 3B+ had better thermals than the 3B and the latest Pi4 with the C0 die is the most optimised of the lot.

I think the Pi4 can sleep at 3ma which make it the best of them all?
Only the Pi Zero gets close at 25ma?

You want something that can throttle subsystems when not used.
That would be the Pi4 with the C0 die version?
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

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LogicEthos
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Re: CM4 power consumption

Thu Nov 12, 2020 3:06 pm

I would have liked a lower power module for IoT projects that are idle most of the time. I'm going to try and under-clock mine, when I get it and see what sort of power it can run at.

Anyone know if it can run on 3.3v only? The spec says 5V, yet I know the Pi Zero runs fine on 3.3v.

dp11
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Re: CM4 power consumption

Thu Nov 12, 2020 3:27 pm

It will almost certainly trip the under voltage lockout @ 3.3v and so won't startup.

cleverca22
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Re: CM4 power consumption

Thu Nov 12, 2020 3:31 pm

LogicEthos wrote:
Thu Nov 12, 2020 3:06 pm
I would have liked a lower power module for IoT projects that are idle most of the time. I'm going to try and under-clock mine, when I get it and see what sort of power it can run at.
i'm not sure underclocking would have much to gain

the C0 stepping from the pi400 (and CM4) basically turns the clock to a component off when its idle, which is effectively a dynamic underclock to exactly the number of cycles you needed

thats what let the pi400 run a lot cooler, so it can get away with 1.8ghz on just a passive heatsink

the only gains i can see from underclocking a C0, is if you underclock it "too far" and then whatever compute your doing starts to run slower, then you have to change the code to do less work per time

but so far, thats all theory, ive yet to get my hands on any C0 chips

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LogicEthos
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Re: CM4 power consumption

Thu Nov 12, 2020 4:08 pm

dp11 wrote:
Thu Nov 12, 2020 3:27 pm
It will almost certainly trip the under voltage lockout @ 3.3v and so won't startup.
Do you know what the 5V is used for that makes it a requirement?

dp11
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Re: CM4 power consumption

Thu Nov 12, 2020 4:31 pm

5v powers the main PMIC just like on Pi4.

trejan
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Re: CM4 power consumption

Thu Nov 12, 2020 8:53 pm

What dp11 said. MxL7704 datasheet lists minimum voltage as 4.0V. If it is < 3.9V it will trigger the undervoltage lockout and won't start. You can't bypass the PMIC as it is also responsible for the RAM and SoC core voltages.

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