How,does it work? RGB RAM modules

[Donniesito]

Hey guys! 

 

Since its' introduction, I've wondered how exactly rgb ram modules work. How does the ram bus provide enough power? How do lighting effects (which have constantly fluctuating power requirements) work? How does this not affect the actual ram? And lastly, how does the programming of the module work?

 

i was under thas impression that the ram bus used every one of those 'pins' -- obviously not. 

 

So! What do you think?  I'd find that show extremely interesting!

[cj09beira]

16 minutes ago, Donniesito said:

Hey guys! 

 

Since its' introduction, I've wondered how exactly rgb ram modules work. How does the ram bus provide enough power? How do lighting effects (which have constantly fluctuating power requirements) work? How does this not affect the actual ram? And lastly, how does the programming of the module work?

 

i was under thas impression that the ram bus used every one of those 'pins' -- obviously not. 

 

So! What do you think?  I'd find that show extremely interesting!

if i was to make an rgb ram, i would make the rgb portion read its instructions from a specific memory adress in the ram, and then that address would be used to control the ram's rgb, then all i would need is a software user interface made to talk to that specific address 

[cj09beira]

the power part, ram receives its main voltage through some of its pins, which is 1.35 for ddr4, and use a boost converter to increase it to around 3v needed to power the leds, they don't use much energy so they wont cause any ram instabilities 

[Mira Yurizaki]

33 minutes ago, Donniesito said:

How does the ram bus provide enough power?

Looking at a random datasheet for DDR4 RAM (https://www.micron.com/resource-details/5ce7698f-058f-49c2-9f27-1372f508c668), the maximum typical current consumption for the module at DDR4-2666 speeds approaches 2A. Now given that some of these high end models for RAM can go up to DDR4-4000 which would increase the current consumption by at least 50% (this is assuming no voltage increases are needed), it could be reasonable to assume the DIMM slots provide at least 4A of current per module.

 

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How do lighting effects (which have constantly fluctuating power requirements) work? How does this not affect the actual ram?

LEDs don't need a lot of power. Taking a random RGB LED part from Digikey (https://www.digikey.com/catalog/en/partgroup/tri-color-rgb-rectangle-with-flat-top-0603-package-chip-leds/34398), the spec sheet says about 20mA is used for any of the channels. But since the supply voltage of DDR4 is 1.2V, this has to be boosted up to at least 3.3V. So each LED is taking up at worst 165mA.

 

There's also probably only two LEDs with a light diffuse strip. So you're looking at worst about 330mA of current consumption.

 

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And lastly, how does the programming of the module work?

The data sheet showed there's some programmable EEPROM that uses an I2C interface. So it's likely there's a MCU or some such that listens on that I2C interface to interpret commands as well as serve the original functions of whatever it needed to do. EDIT: Pins 139, 140, and 141 are I2C pins, so yeah, you can send stuff to the modules if you want.

Edited August 4, 2017 by M.Yurizaki