Thermal test TMC2209 driver @1.7A RMS

I wanted to push my TMC2209 driver design to high-er current. The driver chip is relatively small and even at moderate 1.3A RMS motor current it gets very hot very fast.

Now to be fair 1.3A RMS is probably more than enough to drive most NEMA17 stepper motors. However every once in a while one can get a 1.6A motor or in my case a 1.7A motor. Now in most cases it is not required that you drive the motor with it’s maximum rated current, I just wanted to push the driver and see how it fairs under load.

Here is a picture of my very messy desk with the test setup:

I have my 1.7A NEMA17 motor on a linear rail I used for the test. Above it you can spot my Seek Compact Pro thermal camera. It is not the most accurate instrument, but does the job +/- 5 degree C.

The driver board has one 14x14x7mm heat sink on the driver chip and one 25x25x5mm heat sink on the back of the board, There is also a low RPM 5V 40mm fan blowing air horizontally across the driver boards.

First I configured the driver to use 1.6A RMS current and run a series to G1 X100;G1 X0 commands to move the axis back and forth. I used relatively slow speed, because from my experience this heats the driver the most. This test was uneventful (aka no smoke or major errors), so I proceeded to configure the driver to use 1.7A RMS current.

Here is a picture of the temperature of the board after about 15 minutes of moving the axis back & forth:

The hottest spot is around 54C. While the colors are very dramatic, this is quite cool for this type of setup.

The back side was about 45C:

In conclusion the test was very successful. In previous experiments the drivers would heat up to 70C. In this setup 54C was quite reasonable for the amount of current the driver was handling.

PrntrBoard gets upgraded to 480MHz CPU!!!

I was perusing trough the parts catalog offered by JLCPCB for their assembly service and found this awesome micro controller  STM32H750VB it is quite an upgrade over the good old F407 part. It runs newer Cortex-M7 ARM core, it has double precision FP unit and can run at sweet 480MHz. Best of all it was mostly pin compatible with the F407. I had to re-route one side of the pins, but it was fairly quick.

The only down side is that the build-in flash is a bit limited – 128KB, but I think I can work with that. I’ll order some boards with that processor once the factories in China are bully back in business.

The updated design is on my github page in the “new_cpu” branch.

LCD connector weirdness

There is no shortage of weirdness when it comes to the popular RepRap LCD connectors. The traditional connector is dual 10-pin IDC male sockets.

Alas it appears that someone made a mistake in the original schematics, so now some LCD panels have the connectors backwards. For example the FYSETC Mini 12654 Panel.

I had to create this small adapter to easily flip the direction of the wires:

Here it is i use in my PrntrBoardV2 test prototype: