What's the power consumption of a phone screen if we compare it to the power consumption of the ARM processor. If we take a phone charge where does most go?

Calin said:
If we take a phone charge where does most go?

Depends on what the phone is currently doing. Displaying bright image → backlight will take most power. Playing a game → SoC. Watching Geoffs latest show → show. Scrolling facebook → your brain, or maybe not.

Yoyu would get more accurate answers if you just google... ; )

Depends on what the phone is currently doing

If you don't touch the phone for a day or two everything will be consumed by the processor/electronic circuits I get that. But on an average day when the screen switches on and off what is the power consumption ratio processor/screen I'm looking for a vague estimate. I know it's a variable thing.

If the screen were always on it would be consuming way more than the processor. I guess the correct question is what's the consumption percentage when the screen is on (I know that that too is a variable thing).

Ok, i did the googling for you. Here's some graphs:

https://typexpersonality.medium.com/analysis-of-power-consumption-in-a-smartphone-ff327b8a5172

Random search result, but guess that's more expertise on the subject than what's expectable from game devs.

Calin said:
I guess the correct question is what's the consumption percentage when the screen is on (I know that that too is a variable thing).

Repeating the cry of it depending on what the phone is doing, that's what I see for my own microprocessor hobby work.

Even something as simple as a a single LED on a board can draw significant power if you're trying to maximize battery life for something to run for years. You've mentioned keeping it off as much as possible, and that's very important. From summary a few years back, a guy trying to get maximum life started with a bunch of low-power techniques to get his projects from days of battery life to months, then up to over 3 years of estimated battery life, other articles he links to go into depth.

If you have to have a display, backlights and LEDs draw tons of power, and LCD draws a little less. eInk or ePaper displays set and turn off, which is good. But seriously, even a single LED showing power can drain batteries. On phones you can't change the display, but if you can dim the backlight or turn it off completely that's going to make a huge difference.

Wireless radios take a ton of power, WiFi and Bluetooth are enormous power drains. For IoT devices many articles go in depth about turning on WiFi, using a pre-configured radio setting so you're not wasting power negotiating IP address and whatnot, send your limited message, then turn it off. For phones that isn't practical, but absolutely turn off whatever radios you're not actively using. If you're at home or work on WiFi turn off Bluetooth and cellular. When you leave, turn off WiFi and turn on cellular. Only turn on Bluetooth when you're actively using it, then back off.

Not just sending and receiving over the radios, but also picking up GPS signals is a power draw. For phones if you're not actively using location, turn that off.

Main processors have low power states, the more you're doing with the processor the more power it draws. Phones do a great job of this, when the scheduler gets to the idle task it should generally cut the power. If it can switch from 4 cores to 2 cores and still get enough work done, that's important. If it can drop to 1 core, it should. If it can reduce CPU frequency, maybe dropping from 2 or 3 GHz or whatever it's normal speed is down 800MHz, or 200Mhz, or however low the device supports, it should. That is a tremendous power saver.

Audio circuitry takes power, and running speakers takes power. For my own use, I've found it's generally less power to drive audio circuitry and direct it over Bluetooth to an externally-powered speaker using A2DP protocol than it is to drive a speaker. This will also depend on how loud your speaker is running, louder = more power. You'd need to run your own experiments to decide which needs more power for the device, for my phone and my ESP32 projects it is less battery draw to use Bluetooth headset vs wired headset, but your devices may vary.

Many sensors are the same, although phones don't usually give you the option to turn them off. IMU devices (accelerometer, gyroscope, and magnetic compass) can be powered off when not in use, and if you're programming them most have settings where adjusting the sensitivity also adjusts the power draw. Phones tend to automatically manage power around it.

And finally, your phone probably has a config screen showing approximately where the power is going, what apps are drawing power, how much is going to the screen, and similar. That can help as a guide.

Thank you guys for your kind feedback. That sheds light on the problem.