First of all, thanks for making a smart stepper motor controller! I’ve been hoping for something just like this from Pololu for years (really)!
I just started playing with one and it’s great. I want to bump up the current limit, and I was wondering if the plated pad on the opposite side of the board from the TI chip is intended as a heat sink pad, or if the sink needs to be directly mounted to the chip on the under-side of the board. I am planning on running this in excess of 2 A per phase.
I’m really excited to try pairing a few of these with the Maestro script-able servo controllers. I wonder if that same kind of self-executing script functionality could be baked into future Tic versions?
Yes, the exposed area opposite the driver IC is available for heat sinking; you can also apply a heatsink to the chip package. Claire might follow up with some more details about how well various options work (I think the main answer will be to get some air flow).
I am happy you like the Tic controller so far. I expect to have a low-voltage version available around the end of the month with the DRV8834 driver. Our road map is then to make newer jrk motor controllers with feedback based on the same PIC18F25K50, then to update the Maestros with that microcontroller. That will involve getting scripting working, and the plan is to then add that back to the Tics and jrks with a firmware update. Best case, the scripting would be available in early 2018.
We recently did some heatsink testing with DRV8825 carriers and Tic T825 controllers and the biggest take away (like Jan hinted) was that airflow is way more effective (with or without a heatsink) than just a heatsink alone. For the DRV8825 carriers applying a heatsink to the chip rather than the thermal pad seemed to give a little better results, but we did not notice much difference between the two with the Tic T825. With the Tic T825 we were able to get a few hundred milliamps of extra current by adding just a fan and using a heatsink as well did not really give much more improvement. This is based on fairly small heatsinks of the sort we often see on these stepper drivers, with a relatively casual application using whatever included thermal adhesive (i.e. no measuring of pressures, contact areas, thickness of adhesives, etc.).
