Toshiba e-studio 160 - Scanner Motor Drive Circuit

e-STUDIO160/200/250 SCANNER 7 - 6 December 2002 TOSHIBA TEC
7.4 Scanner Motor Drive Circuit
The drive circuit is mainly comprised of the following:
• Scanner MPU(IC1)
• Motor control IC (IC4)
• Motor driver (IC9)
• Current detection resistors (R9 to R12)
IC1
Scanner MPU
IC4
Motor
control IC
IC9
Motor driver
Scanner motor
A
/A
B
/B
+24V
CN7
BPWM
R16 R15 R14
SG PGSGSG
R13C14C15
CPUA0~19
Scanner control PWA
CPUD0~15
61
BENB 71
BDTB 69
BDTA 68
BSTB 60
BCKO 67
17
6
2,13
5,16 SA 11
2,5
S/A 83
SB 11 4
S/B 18
R11,R12
9
R9,R10
10
6
+5V
2
4
3
Q1
3
14
08-04-01
- Process of Excitation -
IC4 turns the BENB signal to the HIGH level to turn off Q1.
IC4 sends the BPWM signal (current value setting signal) to IC9.
IC4 sends BCKO (Clock Signal), BDTA/BDTB (Serial Data Signal A/B), and BSTB (Strobe Signal)
to IC9 based on the register settings (rotational direction (CW/CCW), excitation method (2-/1-2-/
W1-2-/2W1-2-Phase), and clock (double-edge/single-edge)).
IC9 allows current to flow through each phase of the motor (A, /A, B, /B) based on the timing of
BCKO, BDTA, BDTB, and BSTB, thereby driving the motor.
The current flowing through the motor flows from R9 to R12 to generate voltage. This voltage is
compared with the voltage set by the BPWM signal in IC9 and the current to flow through the motor
is controlled based on its result.