eBay TB6560 Stepper Motor Driver Boards

[irving2008]

Good Day All.

Has anyone here got or do you know anything about the TB6560 stepper motor driver boards that are being sold on eBay.

From the bad english in the ebay listings it looks like thease boards can run upto 36volts and upto 3amp stepper motors.

But detailed info is very limited.

I am just after your toughts on this item.

Thanks for your time.

Best Regards.

First thing to understanmd is never believe what suppliers say the capabilities of their boards are... read the datasheet for the chips and look at the construction.

Here we have 4 TB6560 devices sharing a single force cooled heatsink approx 30mm x 80mm x 10mm. That heatsink has a thermal resistance of about 6decC/watt and with the fan thats maybe improved to 4degC/watt (the airflow is pretty restricted). So each device is effectively fixed to a heatsink of 16degC/Watt (under worst case conditions - all axis functioning) or 12degC/W for 3-axis use.

Now look at the datasheet for the TB6560. Its allowed to run the junction at 150degC max before the thermal shutdown cuts in and the thermal resistance junction to case is 1.5degC/W. So adding that to the heatsink you have (3-axis) 12.5degC/W thermal resistance. So maximum dissipation at 25degC ambient is (150 - 25)/10.5 = 10W.

The power dissipation of the chip is approx 2 x On resistance x output current^2 = 2 x 0.4 x I^2 and this is maximum 10W so rearranging

I = sqrt(10/(2 x 0.4)) = sqrt(10/0.8) = 3.5A

So on the face of this this board can run 3A/phase steppers at full output on 3-Axis, and will probably be ok on 4-axis, but its pushing close to the thermal cutoff of the chip...