Drivers; Pf Motor Driver - Citizen CL-E700 series Technical Manual

Chapter 2 Operating Principles
2-2.
Operation of Control Parts

2-2-5. Drivers

(1) PF motor driver

This is a driving circuit to drive the "SA PF Motor" (stepping motor).
The following illustration shows a simplified circuit.
The "SA PF Motor" is driven by the bipolar constant current chopper method. The excitation
mode for the motor is the 1-2 phase.
The power supply to the "SA PF Motor" is controlled by the VMTON signal at pin N3 of FPGA
(U5). When the VMTON signal is "High", Q20 turns ON, FET Q18 turns ON, and +24V DC
(VMT) is supplied to the "SA PF Motor".
The excitation mode of the "SA PF Motor" is determined by the PFMS1 and PFMS2 signals at
pins F2 and F3 of the FPGA. The rotational direction is determined by the PFDIR signal and
the motor drive pulse is fed from pin A4 (PFCLK signal). The motor driver (U13) drives the "SA
PF Motor" using these signals.
The digital-to-analog converter (U16) controls the drive current to the "SA PF Motor". Its output
signal (DAPFMT) is fed to pin 15 (REF) of the motor driver (U13) to determine the amount of
drive current to the "SA PF Motor".
In power saving mode, the VMTON signal goes to "Low" and VMT to the motor driver (U13)
stops. At this time, the PFOFF signal at pin A6 of FPGA goes to "High", Q6 turns ON, and the
DAPFMT signal output from the digital-to-analog converter (U16) is fixed to a certain low
voltage level.
U5
FPGA
N3
21_N1
A4
PFCLK
81_A4
D1 PFDIR
11_D1
nPFENB
F1
11_F1
A12
nPFSLEEP
71_A12
F2
PFMS1
12_F2
F3 PFMS2
13_F3
B5
82_B5
B4
82_B4
D4
14_D4
A6
81_A6
CL-E700 series
L: Turns on Q18 to supply
power to the PF motor.
R137
VMTON
Q20
DTC114EM
R138
Motor current control
U16
D/A Converter
2
13
AO1
CLK
12
AO2
DI
11
LD
R2A20164SA
+3.3V
R165
+24V
R136
C152
Q18
TJ15S06M3L
(+24V)
VMT
U13
Motor Driver
19
VCC1
24
VCC2
14
CLK
17
DIR
2
ENABLE
12
SLEEP
8
MODE0
9
MODE1
DAPFMT
15
REF
C116
A4984SES
R83
Q6
DTC114TM
2-32
J5
PF Motor
1
21
OUT1A
2
18
OUT1B
3
22
OUT2A
4
1
OUT2B
[SA PF Motor]
[SA Main PCB]
M