- Stepper driver with Toshiba TB6560(A)HQ -
Circuit and PCB
The circuit is built around the TB6560(A)HQ as described in the Toshiba datasheet. It has a build-in connector for a reference switch.
The current flow to the motor is adjusted by selecting different values for R1 and R2. The formula is IOUT=0.5(V)/RNF(Ώ). Use low inductance 1W to 2W resistors for R1 and R2. Do not use wire wound types.
The oscillator frequency is adjusted by selecting different values for C4. Refer to the schematic for details.
When using the TB6560AHQ you should leave the protection diodes unpopulated because the TB6560AHQ has build-in diodes. Under some circumstances I found that they disturb the operation of the TB6560AHQ's constant current regulation.
The board is populated on both sides. The bottom side holds the TB6560. You will have to bend its pins to mount it flat onto the PCB with its cooling pad facing away from the PCB. Place plastic washers between the TB6560 and the board to create a little gap between them. The TB6560 has to be cooled. Isolate the TB6560 from the heatsink or the motor you mount it on using a silicone pad.
There are a couple of solder jumpers on the board to adjust the operating mode and the current decay. Please refer to the schematic and the datasheet for more details.