Sharp SF-A57 Service Manual page 37

[c] Paper feed motor (DFM) drive circuit
This circuit controls the paper feed motor rotation and stop and the rotating direction. It is composed of the G/A (IC7) and the exclusive hybrid IC
(IC10), etc.
The motor rotation, stop, and rotating direction are controlled by the combination of binary logics inputted to the G/A through the data bus from the
CPU.
This provides control signals to the G/A 65 ∼ 68 pins.
The G/A 65 pin and 66 pin are for the PWM output for speed control. (Normal rotation, 65 pin; reverse rotation, 66 pin)
These signals are inputted to IC10.
IC 10 is a hybrid IC including 4 power MOSFET's, and drives the motor by taking the G/A output 65 ∼ 68 pins.
The motor operates as follows by the combination of 25 ∼ 28 pins.
— 65
Before start 0
CCW 0
CW PWM
Brake 0
In the brake mode, the both terminals of the motor are shorted, generating a great braking torque to stop the motor.
G/A
(IC7)
67
MIH1
65
MIL1
68
MIH2
66
MIL2
72
CHGCLK
66 67 68
0 0 0
PWM 1 0
0 0 1
0 1 1
IC10
4
INA OUT1-1
2
INB OUT1-2
6
INC OUT2-1
3
IND OUT2-2
1
CLK
+5V
13
VCC2 VZ
VCC1-1
16
SG VCC1-2
C49
0.1µ F
STK681-050
To power control circuit
Paper feed motor drive circuit
10
DF1B-9P-2^5DSA
L1 72µ H
11
DFM1 CN5-1
SK-BMS-5H
6
L2 72µ H
7
DFM2 CN5-2
SK-BMS-5H
2
FD+24V
9
C34
8
1µ F
C28
0.1µ F
PGND
– 36 –
Paper feed
DFM
motor