What are the specifications of the dual voltage controller of the Ender 3/CR-10?

Question

Following on from What level of voltage does the Creality Ender-3 run at?

Dave's answer states that both 12 V and 24 V can be used on the controller board. It also goes on to say that the controller board is used in both configurations in two different printers:

• Ender 3 and;
• CR-10

I would like to know how this dual voltage operation works:

• Does it use both voltages at the same time, or either one or the other?
• Are there two different electrical inlets or are they the same?
• Does it auto-detect or are there jumpers used to configure or are the components tolerant to both voltage levels?

Also related:

• What is the board used?
• Is the board a proprietary design or a standard third party board?
• Does anyone have any photos of the board and/or schematics?

Answer 1

I own the Ender 3, and it runs on 24V, as this photo of the power supply shows:

From power supply to the board, it uses a 2-wire line connected with a XT60 plug/jack that is common on RC cars:

The board itself is a proprietary design and labeled as "V1.1.2". The Voltage in is the lowest input on the left:

The Cooling fan (blue-yellow wire), the hotend cooling fan, heater cartridge (white shielded), bed heater (left black-red), board cooling fan (middle red-black) run (in this setup) on 24V. The Logic connectors (black-black & White-white) run 5V logic. I could not figure out the voltage of the stepper motors (upper row).

I have not figured out how the power management circut works, but it achieves this:

• Supply voltage $ U_S = 12\ \text V \lor 24\ \text V $
• Logic Voltage $ U_L = 5\ \text V $
• Sensor Voltage $ U_{sens} = U_L$
• Hotend Cooling Fan $ U_{cool} = U_S$
• Hotend Heating Cartridge $ U_{hot} = U_S $
• Heatbed $ U_{bed} = U_S $

The chip's caption can't be read on the photo, but it is labeled as "Δ ATMEL // ATMEGA1284P // AU 1726"

For the pinout, a german maker did determine, that it the configuration of a Sanguino equipped with an Atmega1284P 16Bit works for compiling firmware and flashing via a bootloader.

Answer 2

This answer addresses the input voltage. If you look up the official replacement board at the official Creality store the board features a single pair of connectors next to it says: 12 V / 24 V. So you can either use 12 V, or 24 V, not both. An internal regulator will most probably reduce the voltage anyways.

Please note that (kindly reminded by user profesor79 through the comments) that the microprocessor on these boards only use 5 V. So any voltage you supply (12 or 24 V), the voltage regulator will always make sure the microprocessor does not get more than 5 V. However, that does not necessarily apply to all peripherals connected to the board! This should be verified if for the peripherals also a voltage regulator is used. One of my own boards, the RUMBA board can be fed by any voltage ranging from 12 V - 35 V, but this also applies to the peripherals like the heater cartridge and the fans! I use the RUMBA with a 24 V power supply, so I need to use 24 V fans heater elements and heat bed.