LC78626 Просмотр технического описания (PDF) - SANYO -> Panasonic

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LC78626

DSP for Compact Disk Players

SANYO -> Panasonic 

LC78626E

6 The CLV Servo Circuit Pin 20: CLV+, Pin 21: CLV-, Pin 22: V/P

Code

$04

$05

$06

$07

COMMAND

DISC MOTOR START (Accelerate)

DISC MOTOR CLV (CLV)

DISC MOTOR BRAKE (Decelerate)

DISC MOTOR STOP (Stop)

RES = low

q

CLV+ is the signal for accelerating the disk in the forward direction, while CLV– is the signal for decelerating the

disk. Depending on the commands from the microcontroller, one of the following four modes is selected: Accelerate,

decelerate, CLV, or stop. The CLV+ and CLV– outputs for each mode are as shown in the table below.

MODE

Accelerate

Decelerate

CLV

Stop

CLV+

high

low

Pulse output

low

CLV–

low

high

Pulse output

low

* The CLV servo control command is such that the TOFF pin is low only when the CLV mode is in effect, and it is high

otherwise. The TOFF pin control by the command is only active when the CLV mode is in effect.

(1) The CLV Mode

In the CLV mode the rotation of the disk is detected from the HF signal, and a precise linear speed of rotation is

derived by exerting the respective forms on control when the internal modes of the DSP change. The PWM frequency

is 7.35 kHz. The V/P has a high output when the internal mode is the rough servo, and a low output when the internal

mode is phase control.

Internal mode

CLV+

CLV–

V/P

Rough servo (when the rotational speed is determined to be low)

high

low

high

Rough servo (when the rotational speed is determined to be high)

low

high

high

Phase control (when the PCK clock is running)

PWM PWM

low

(2) Switching the Rough Servo Gain

Code

$A8

$A9

COMMAND

DISC 8 cm Set

DISC 12 cm Set

RES = low

q

When the internal mode is the rough servo, the CLV control gain for the 8 cm disk can be reduced by 8.5 dB from the

level for the 12 cm disk.

No. 5692-14/32

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