SKT672-080-E Datasheet, PDF (6/18 Pages) ON Semiconductor – Stepping Motor Driver

STK672-080-E
Power-on Reset
The application must perform a power-on reset operation when VCC2 power is first applied to this hybrid IC.
Application circuit that used 2W1-2 phase excitation (microstepping operation) mode.
VCC2=5V
VCC1=10V to 45V
VCC2=5V
6
184
194
142
ATwo-phase ^{stepping motor}
5
AB
4
B
3
+
BB
2
VF 0.3V
ENABLE
CLK
+
CBW
RESET
15
STK672-080-E
11
1
13
10
MOI
14
Simple power on reset circuit
(This circuit cannot be used for
power supply voltage drop
detection.)
RoX
7
SG
PG
VCC2=5V
Ro1
Vref
Ro2
We recommend a value of about
100Ω for Ro2 to minimize the
influence of the Vref pin internal
impedance, which is 6kΩ
RoX: Input impedance: 6kΩ ±30%
A13261
Setting the Motor Current
The motor current IOH is set by the Vref voltage on the hybrid IC pin 7. The following formula gives the relationship
between IOH and Vref.
RoX = (Ro2 × 6kΩ) ÷ (Ro2 + 6kΩ)
(1)
Vref = VCC2 × RoX ÷ (Ro1 + RoX)
(2)
IOH =
1_×
K
Vref
Rs
(3)
K: 4.7 (Voltage divider ratio),
Rs: 0.15Ω (This is the hybrid IC's internal current detection resistor. It has a tolerance of ±3%.)
Applications can use motor currents from the current (0.05 to 0.1A) set by the duty of the frequency set by the oscillator
up to the limit of the allowable operating range, IOH = 2.8A
0A
Function Table
M2
0
M1
0
M3
1
2 phase excitation
0
1-2 phase excitation
Motor current waveform
Ioave
IOL IOH
A13262
0
1
1
Phase switching clock edge timing
1
0
1
1-2 phase excitation
W1-2 phase excitation
W1-2 phase excitation 2W1-2 phase excitation
2W1-2 phase excitation 4W1-2 phase excitation
Rising edge only
Rising and falling edges
CWB
Forward
0
Reverse
1
ENABLE
RESET
Motor current is cut off when low
Active low
No.6507-6/18