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.
stk672-080 microstepping

Excitation table:

JP1 (M1)   JP2 (M2)
 0  0  full step
 1  0  half
 0  1  1/4
 1  1  1/8

 Bom Parts

Value

C1  1uF
C2  150-220uF 63V
D1  1N4148
JP1, JP2  jumpers
LED1  LED3MM
R1,2  100
R3,R4  1k
R5,R6  10k
R7  2.2K R-TRIMM64P
SV1  MA05-1 pins
IC1  Sanyo STK672-080
About Microstepping: http://www.zaber.com/wiki/Microstepping_Tutorial
Vanja Vršić
Vanja Vršić

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