Toshiba 4560 Service Manual page 70

7.4 Pulse Motor Drive
7.4.1 Pulse motor drive circuit (constant current type)
The scanning motor (M2) is driven by hybrid IC STK6713BMK4 of the unipolar constant current chopper
drive. The driving circuits of A and A phases are shown below. Since B and B phases are exactly the
same, they are omitted here.
i
ON
A
V
DD
A
1 2
V
CC2
F1
D
Internal equivalent circuit of STK6713B
The circuit configuration on the inside of the IC is composed of each phase excitation switching section
(IC2), driver (F1, F2), comparator (IC1), and current detection resistor (R7).
The following explains the circuit operation when the A phase is excited.
4560/4570 OPTICAL
+24V
i
OFF
A
A
øA
3
15
F2
IC2
IC2
IC2
IC2
D/A
62353
R12
R14
øA Td1 V
ref
13 8 9
IC41
C1
R3
E
R1
B
C
R5
—
A
+
IC1
D1
R7
7 - 8
187
DADAT
G/A
R18
C10
PG 4
DG
5
GND
Nov. 1997 © TOSHIBA