eBay TB6560 Stepper Motor Driver Boards

[Mad Professor]

Over the last few weeks I have had a number of people contact me via PM's asking me questions regarding the TB6560 boards.

One that keeps being asked is the lack of performance (speed) when using microstepping.

I have so far been unable to answer this one.

I had some free time today, so I decided to test my board with microstepping, and guess what I have the same lack of performance (speed).

I scoped the input step signal from the computer, and the step signal to the TB6560 chip.

The step pulses (0-5KHz) from the pc can be seen without a problem.

But there is something strange with the step pulses from the opti to the TB6560.

I was expecting to see a 0-5v square wave, or at least something close to it.

But it's more a 0-5v pulse then ramps back to ground.

The faster the step pulse the more the ground moves away, and at around 4.8KHz the ground is so high that the TB6560 can no longer see the step pulses.

http://www.mad-professor.co.uk/Misc/...0@%20300Hz.jpg

http://www.mad-professor.co.uk/Misc/...@%204.1KHz.jpg

http://www.mad-professor.co.uk/Misc/...20@%205KHz.jpg

Blue scope trace is the input to the board, and the red scope trace is the step input at the TB6560 Chip.

Following the traces on the PCB this is what I have come up with for the Schematic.


Looking at the datasheet for the TB6560 says that it is good for upto 15Khz.