328

Optical disc ICs

BA6392FP

FInput / output circuits

FCircuit operation

(1)

Fig. 3 shows the inputs from the digital servo IC for

CH1-CH3 drivers (all drivers except the spindle).

SW1 is on when the forward input signal (HIGH level,

over 2.4V) is present. SW2 is on when the reverse input

signal is present (Fig. 2)

generates an integral waveform based on the duty of the

input waveform. The BTL is output from BUF1 and BUF2

(Fig. 4).

To maintain the HIGH level with forward (or reverse) in-

put, the DC voltage generated at point A is :

R

2.5V (reverse :

*2.5V)

such that a voltage differential of 5V is generated be-

tween output pins. The time constant is :

R

C = 2.4

µsec