2. Lens Motor Drive Circuit
Figure 3-203 shows the circuit used to control the lens motor (M3).
The lens motor is a 2-phase stepping motor, and is controlled by the lens motor drive
pulse command (LEA, LEB) and the lens motor hold command (LEHLD) generated by
the DC controller. The direction of its rotation, on the other hand, is controlled by
changing the output timing of the LEA command and the LEB command.
The LEHLD command remains ‘1’ while the lens motor is rotating, applying 24 V to
the motor. The LEHLD command remains ‘0’ while the motor is at rest, applying 5 V to
the motor by way of applying brakes.
Figure 3-203
3-4
CHAPTER 3 EXPOSURE SYSTEM
COPYRIGHT © 1997 CANON INC. CANON NP6330 REV.0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
Drive circuit
-2B
-4B
-3B
-13
-14
-12
LEA
LEHLD
LEB
J106
J202
DC
controller
PCB
Motor driver 1 PCB
±5V
±5V
±24VB
LEPOW
LEPOW
Lens motor
LEB
*
LEA
*
LEA
LEB
M3