• CLV mode

In CLV mode the LC78624E detects the disk speed from the HF signal and provides proper linear speed using

several different control schemes by switching the DSP internal modes. The PWM reference period corresponds to

a frequency of 7.35 kHz. The V/P pin outputs a high level during rough servo and a low level during phase control.

• Rough servo gain switching

For 8 cm disks, the rough servo mode CLV control gain can be set about 8.5 dB lower than the gain used for 12 cm

disks.

• Phase control gain switching

The phase control gain can be changed by changing the divisor used by the dividers in the stage immediately

preceding the phase comparator.

No. 5811-11/27

LC78624E

Internal mode

V/P

Rough servo (velocity too low)

High

Low

High

Rough servo (velocity too high)

Low

High

High

Phase control (PCK locked)

PWM

PWM

Low

Code

Command

RES = low

$B1

CLV PHASE COMPARATOR DIVISOR: 1/2

$B2

CLV PHASE COMPARATOR DIVISOR: 1/4

$B3

CLV PHASE COMPARATOR DIVISOR: 1/8

$B0

NO CLV PHASE COMPARATOR DIVISOR USED

q

q

Code

Command

RES = low

$A8

DISC 8 cm SET

$A9

DISC 12 cm SET

q

q

A09906