STB Cool Stepper Driver
Currently this is work in progress. Some samples are available for testing.
List of Boards
STB Cool Stepper Driver V2.00 (8+8 pins):
- If the current is too high for the heat sinking, the motors will stop and the powersupply of the printer must be cycled.
- G3D driver
- SureStepr SD82B - http://www.panucatt.com/product_p/sd82b.htm
- DRV8825 Stepper driver (1.5 A max w/o heatsink! 2.2 with) - http://www.pololu.com/catalog/product/2132
Tuning motor current
From the TI DRV8825 datasheet [], the calculation for the maximum trip current is:
The sensing resistors are Rs=0.1 ohm, so a Vref of 1.25V should produce a maximum current of 2.5A. By default the STB Cool Stepper Driver is limited to 1.8A which is enough for most applications and no special heatsink is necessary. For the full 2.5A range SJ1 on the backside of the driver has to be shorted. The reference voltage can be measured direct on the center tab of the potentiometer R4.
Best cooling results are given if the heatsink is mounted on the area on the backside of the PCB where the soldermask ist cut out.