Pulse Motor Drive Circuit - Toshiba 1550 Service Manual

7.4 Pulse Motor
7.4.1 Pulse motor drive circuit (constant current type) (M2)
The scanning motor is driven by hybrid IC-STK6712BMK3 of the unipolar constant current chopper
drive. The driving circuit for phase A and A is shown below.
The same circuit is also used for the drive of phase B and phase B.
+5VSW
V 1
CC
Drive voltage
regulator
IC1
Internal equivalent circuit of STK6712B
The circuit composition in the IC consists of each phase excitation switching section (IC2), a driver (F1,
F2), a comparator (IC1) and an electric current detection resistance (R11). The circuit operation in the
case of excitation of phase A is described below:
Mar. 1998 © TOSHIBA
+24V
i i
ON OFF
A A
øA
2 3
15
F1 F2
IC2
IC2
+
+5V R11 R10
D2
øA Td1 NC
13 8 12
C1
R7
E
R5
B
C
R9
IC1
D1
R1
7 - 15
R9
C10
SG
R31
R35
V
ref
9
A
PG 4
DG
SG 5
SG
1550/1560 OPTICAL
CPU