STK672-442BN-E

No.A2249-7/28

[Setting the motor current]

The motor current, IOH, is set using the Pin 19 voltage, Vref, of the hybrid IC.

Equations related to IOH and Vref are given below.

Vref

 (RO2  (RO2+RO1))VDD(5V) ··········································· (1)

IOH  (Vref  4.9)  Rs ······························································· (2)

The value of 4.9 in Equation (2) above represents the Vref voltage as divided by a circuit inside the control IC.

Rs: 0.122

 (Current detection resistor inside the hybrid IC)

IOH

0

[Smoke Emission Precuations]

If Pin 18 (S.G terminal) is attached to the PCB without using solder, overcurrent may flow into the MOSFET at VCCON

(24V ON), causing the STK672-442B-E to emit smoke because 5V circuits cannot be controlled.

Function Table

M2

0

0

1

1

CLOCK Edge Timing for

Phase Switching

M1

M3

0

1

0

1

1

2-phase excitation

selection

1-2-phase excitation

(IOH=100%)

W1-2 phase

excitation

2W1-2 phase

excitation

CLOCK rising edge

0

1-2 phase excitation

(IOH=100%, 71%)

W1-2 phase

excitation

2W1-2 phase

excitation

4W1-2 phase

excitation

CLOCK both edges

IOH=100% results in the Vref voltage setting, IOH.

During 1-2 phase excitation, the hybrid IC operates at a current setting of IOH=100% when the CLOCK signal rises.

Conversely, pseudo micro current control is performed to control current at IOH=100% or 71% at both edges of the

CLOCK signal.

WB pin

Forward/CW

0

Reverse/CCW

1

ENABLE

 RESETB pin

ENABLE

Motor current cut: Low

RESETB

Active Low

5V

R01

R02

R3

5V

R02

R3

Vref

Vref

R01