Panasonic BB-HCM580A Service Manual page 11

[LENS drive motor control]
The CPU controls the driver (IC901) for the LENS motor drive that is mounted on the LENS board by the three-wire serial sig-
nals (SDI, SCL, and MO_LD) and by the motor drive timing signal (VD_MOT). The output current, pulse period, and the number
of pulses are also set up by the driver. This LENS motor drive driver (IC901) controls both of the ZOOM lens drive and FOCUS
lens drive motors using the micro step drive control method. The power supply to drive the motors is +5.7V that is supplied by
the DC-DC converter circuit on the TILT board via the VIDEO board.
[IRIS drive control]
The IRIS has been adjusted in the factory and the adjusted values are saved in the Flash memory (IC104) on the CPU board. In
the initialization process when the power is turned ON, the adjusted values are written in the DA converter (IC903) on the LENS
board. No subsequent process to write the data into the DA converter will be carried out. Once the adjusted values are written in
the DA converter, the output voltage from the DA converter can be controlled. The DA output is applied in the IRIS control cir-
cuit. The IRIS unit of the lens is controlled with the method called the Pulse Width Modulation (PWM).
[LED control]
Red and green LEDs are used in the LED (LED901) indicator. LEDs are turned on, blinked or turned off by turning ON/OFF the
transistors (Q901 and Q902) that are connected to the LEDs. The transistors are turned ON/OFF from the output port of the
CPU (IC102) on the CPU board.
LED_R LED_G
H H
H L
L H
L L
Q901 Q902 LED COLOR
ON ON
ON OFF
OFF ON
OFF OFF OFF the light
11
BB-HCM580A
Orange
Red
Green