3.1.6 Spacing drive circuit
(1)
Spacing
motor
control
The motor control
LSI
(Qll:
MSM6990) outputs the spacing motor phase signals
(SP-U,
SP-V,
and
SP-W)
in accordance with the spacing command from the microprocessor, and at the same
time outputs the overdrive signal (SPD-A).
The SPD-A signal is a fixed-period pulse signal. The pulse width is controllable by the program,
and is used to control the motor drive time.
The SP ON/OFF signal is used to control acceleration and deceleration motor torque.
The motor driver (MTDV) drives the spacing motor in accordance with these signals. Pins 9 and
11 of the MTDV are for the protection circuits against overvoltage and overcurrent,
respectively.
SP-u
.-I
SP-v
SP-w
SPD-A
64
ps
l-l
SP-ON/OFF
Overdrive
current
wave form
3-7