STK672-110-E Sanyo Semiconductor Corporation, STK672-110-E Datasheet - Page 5

• Manufacturer Part Number: STK672-110-E
• Description: Two-phase Stepping Motor Driver Square Wave Drive Output Current 1.8a
• Manufacturer: Sanyo Semiconductor Corporation

Input Pin Functions (CMOS input levels)
• A simple reset function is formed from D1, CO4, and RO3 in this application circuit. With the CLOCK input held low,
• See the timing chart for the concrete details on circuit operation.
Usage Notes
• 5V system input pins
See the timing chart for details on the CLOCK, MODE, CWB, and other input pins.
[Vref <Motor current peak value setting>]
In the sample application circuit, the peak value of the motor current (I OH ) is set by RO1, RO2, and V DD (5V) as
described by the formula below.
I OH = Vref ÷ Rs Here, Rs is hybrid IC internal current detection resistor
Vref = (R02 ÷ (R01 + R02)) × 5V
STK672-110-E: Rs = 0.22Ω
CLOCK
MODE
CWB
RESETB
when the 5V supply voltage is brought up a reset is applied if the motor output phases A and BB are driven.
If the 5V supply voltage rise time is slow (over 50ms), the motor output phases A and BB may not be driven. Increase
the value of the capacitor CO4 and check circuit operation again.
[RESETB and CLOCK (Input signal timing when power is first applied)]
As shown in the timing chart, a RESETB signal input is required by the driver to operate with the timing in which the
F1 gate is turned on first. The RESETB signal timing must be set up to have a width of at least 20μs, as shown below.
The capacitor CO4 and the resistor RO3 in the application circuit form simple reset circuit that uses the RC time
constant rising time. However, when designing the RESETB input based on CMOS levels, the application must have
the timing shown in figure 1.
Pin
Pin No.
Rise of the 5V supply voltage
RESETB signal input
CLOCK signal
9
8
7
6
Reference clock for motor phase current switching
Excitation mode selection
Motor direction switching
System reset and A, AB, B, and BB outputs cutoff.
Applications must apply a reset signal for at least 20μs when power is
first applied.
Figure 2 Motor Current I O Flowing into the Driver IC
Figure 1 RESETB and CLOCK Signals Input Timing
I OH
0
Function
STK672-110-E
At least 20μs
At least 10μs
Operates on the rising edge of the signal
Low: 2-phase excitation
High: 1-2 phase excitation
Low: CW (forward)
High: CCW (reverse)
A reset is applied by a low level
Input conditions when operating
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