I am involved in an art installation that uses Sparkfun V13 Autodrivers to control a series of stepper motors.
We are occasionally seeing the chips burn out. On the few occasions I have observed this, it appears to be when there is a communication error for whatever reason (when I observed it there was a loose connection), and one or motors start to lock or move very fast. In the most recent incident, I suspect the motor might have been prevented from moving, although i wasn’t there when it happened. In this case, all 4 drivers in the system burned out, implying a chain of events perhaps.
The chips always seem to burn out around pins 2, 12, 26 and 16. From the schematic i see these are all connected to the motor power supply, so i guess the motors are drawing too much current. However, we have a 2.5A, 240V inline fuse on that supply at each driver, and the chip is rated to 3A rms and 7A peak. The fuses never blow. Any ideas what we are doing wrong?
I think this would not be the cause, but for some reason the designer of this installation is powering the board with 5V via the reset pin and the jumpers are set to ‘3v’ rather than ‘EXT 3-5v’. I am trying to ascertain why they did that.
any ideas greatly appreciated! Here is a photo of a typical burn out: https://drive.google.com/open?id=1O4hR2 … T3umcwdjOc
The motor supply voltage is 24V by the way.
Any ideas from Sparkfun Tech Support on this would be greatly appreciated…
Hi Roy.
I have to admit that I don’t know too much about this particular product but I’ll try to help.
We’ve had sporadic reports of this happening over the years but were never able to determine a cause for each specific case. A loose motor connection or unplugging / re-plugging a motor can definitely blow the driver chip though and we have seen that happen on this and other stepper driver ICs.
I think this would not be the cause, but for some reason the designer of this installation is powering the board with 5V via the reset pin and the jumpers are set to ‘3v’ rather than ‘EXT 3-5v’. I am trying to ascertain why they did that.
This could very well be what’s causing your issue, as the reset pin is not supposed to be used as a power supply. If you have the jumper set to 3V rather than EXT 5-3V your logic power is derived from a internal voltage regulator that’s getting it’s power from the motor power pins and you’d want to leave the 3-5V connectors disconnected. In this state, the chip is expecting 3.3 volt logic so make sure whatever is feeding data into the board uses 3.3 volt logic rather than 5 volt.
It might be safer to leave that jumper in the 3-5V position and apply power via the 3-5V headers on the board rather than letting the chip self power. Whatever system you’re using to send commands to the board should be able to supply the IC at the same voltage it communicates with.