Cheap Microstepping system with STK672-080

The STK672-080 is a stepping motor driver hybrid IC that uses power MOSFETs in the output stage. It includes a built-in microstepping controller and is based on a unipolar constant-current PWM system. It supports five excitation methods: 2 phase, 1-2 phase, W1-2 phase, 2W1-2 phase, and 4W1-2 phase excitations, and can provide control of the basic stepping angle of the stepping motor divided into 1/16 step units. It also allows the motor speed to be controlled with only a clock signal.

Conditions:

• upto 45V supply voltage;
• upto 3.3A (2.8 without heatsink)
• step – dir – enable command pins (internal traslator);
• built-in sensing resistors;
• pwm;

Limitations:

• 1/16 of steps it is not a true ‘microstepping’ because it is obtained generating a step on the rising and the falling edges of the signal pulse. In our environment (CNC machines), therefore, it is useless (we can consider, for this reason, a max of 1/8 step);
• max input pulse frequency is 50Khz. It means that using a 1/8 microstepping with a 200 steps motor we can obtain, at max, a theoretical 31,25 turns per second.

Excitation table:

About Microstepping: http://www.zaber.com/wiki/Microstepping_Tutorial