DP-1100B II DP-1100B II
1 - 5 - 6 F G & D I S C M O T O R D R I V E A N D S T O P O P E R A T I O N S
1. CIRCUIT DESCRIPTION
Fig. 1 - 5 - 6
1 . T h e f r e q u e n c y g e n e r a t o r consists of a polarized m a g n e t i c
ring a t t a c h e d t o t h e r o t a t i n g s p i n d l e of t h e disc m o t o r a n d
a p r i n t e d p a t t e r n in t h e f o r m of c o i l , w h i c h is p r o v i d e d at a
relative p o s i t i o n b e l o w t h e m o t o r s p i n d l e . W h e n t h e m o t o r
r e v o l v e s , a 2 0 Hz pulsive c u r r e n t w i t h is s e n t o u t per e a c h
r e v o l u t i o n o f t h e m o t o r .
2 . It is f e d t o pin 7 of Q 1 0 1 a n d a sine w a v e signal w i t h a n
a m p l i t u d e of ± 5 V is available at pin 8 . It is c o n v e r t e d i n t o
a pulse signal by Q 1 0 8 a n d Q 1 0 9 , d i v i d e d t o a T T L level
by R 2 3 7 a n d R 2 3 8 a n d t h e n a p p l i e d t o pin 3 9 of IC15
( T C 1 5 G or T 7 0 0 1 ) as FGS. T h e FGS is 6 t i m e s m u l t i p l i e d
in IC15 ( T C 1 5 G or T 7 0 0 1 ) t o be DOCK o u t p u t a n d 1 / 3 0
d i v i d e d t o give FG4 at pin 3 6 . S i n c e t h e FGS i n c l u d e s 2 0
pulses per o n e disc m o t o r r e v o l u t i o n , t h e DOCK c o n t a i n s
1 2 0 pulses per a r e v o l u t i o n a n d t h e FG4 i n c l u d e s 4
pulses.
T h e DOCK is used t o d e t e c t a d r o p o u t p o s i t i o n (Refer to
s e c t i o n 1 - 5 - 1 5 ) . T h e FG4 is c o u p l e d t o pin 1 4 of IC8
( T C 9 1 7 8 F ) o f d e t e c t t h e r e v o l u t i o n of t h e disc m o t o r .
3 . T h e r e v o l u t i o n c o n t r o l o f the disc m o t o r is a c c o m p l i s h e d
by APCO ( f r o m pin 19) a n d A F C O ( f r o m pin 2 0 ) . Both of
t h e signals are P W M ( p u l s e - w i d t h m o d u l a t i o n ) signals w i t h
a carrier f r e q u e n c y of 8 . 2 7 kHz in t h e CLV m o d e . W h e n a
disc is r e v o l v i n g at a n o r m a l s p e e d , b o t h of t h e A F C O a n d
APCO are c l o c k w a v e f o r m s i g n a l s w i t h a f r e q u e n c y of
8 . 2 7 kHz at a 5 0 % d u t y . S i n c e t h e A F C O r e g u l a t e s a
r a n g e of zero r e v o l u t i o n t o h i g h r e v o l u t i o n of t h e disc
m o t o r , it m a y be f i x e d at " H " or " L " level in s o m e i n
s t a n c e s .
4 . T h e APCO a n d t h e A F C O are i n t e g r a t e d by R 8 5 a n d C 3 3 ,
a n d R 8 6 a n d C 3 2 r e s p e c t i v e l y . T h e y are t h e n a d d e d via
R 8 7 a n d R 8 8 . T h e a d d e d s i g n a l is p u t t o pin 7 of IC4
( 1 / 2 ) . T h e o u t p u t signal g o e s t h r o u g h a l o w - p a s s filter to
regulate the disc m o t o r r e v o l u t i o n . C 3 5 a n d R 3 5 are for
phase c o m p e n s a t i o n . L 2 0 4 is a noise filter.
5 . Q 1 7 is in a n OFF state d u r i n g n o r m a l play. It is O N w h e n
the disc m o t o r is n o t r u n n i n g , p r o v i d i n g 0 V o u t p u t f r o m
IC4 ( 1 / 2 ) . T h i s O N / O F F o p e r a t i o n is a c h i e v e d by MSP a n d
FGS. M S P is a n o u t p u t signal m a d e available at pin 1 5 of
IC15 ( T C 1 5 G of T 7 0 0 1 ) by t h e m i c r o p r o c e s s o r . W h e n it
is at " H " level, Q 1 7 is t u r n e d OFF a n d t h e disc m o t o r is
d r i v e n t o r u n .
6 . Since t h e FGS p r o v i d e s 2 0 pulses per o n e r e v o l u t i o n of t h e
disc m o t o r as e x p l a i n e d p r e v i o u s l y , it m a k e s pin 7 of IC16
" H " level t h r o u g h D 4 0 d u r i n g t h e r e v o l u t i o n of t h e m o t o r
a n d Q 1 7 is t u r n e d OFF. If disc s t o p s r e v o l u t i o n a n d t h e
FGS b e c o m e s " L " , Q 1 7 t u r n s O N t o s t o p t h e disc m o t o r .
T h u s a n a c c i d e n t a l r o t a t i o n of t h e disc by noises or distur
b a n c e s is p r e v e n t e d .
Summary of Contents for DP-1100 B
Page 3: ...D P 1 1 0 0 B II D P 1 1 0 0 B II I BLOCK DIAGRAM ...
Page 32: ...D P 1 1 0 0 B II 1 CIRCUIT DESCRIPTION Disc Scratch Dust RFES D C O N D O C K Fig 1 2A 3 5 ...
Page 112: ...2 IC OPERATION OF EACH CIRCUIT AND D P 1 1 0 0 B II PIN DESCRIPTION Fig 2 4 1 G 1 ...
Page 117: ...DP 1100B II I OPERATION OF MAIN MICROPROCESSOR Fig 3 1D Q data reading flow chart ...