Page 1
Circuit Description
Power Supply L959AY
! CCT diagram
! Component layout diagram
! Parts list
Main Board L960AY
! CCT diagram
! Component layout diagram
! Parts list
Display Board L961AY
! CCT diagram
! Component layout diagram
! Parts list
Transformers
! L924TX
! L925TX
Mechanical Assembly
! Exploded view diagram
! Mechanical and packing part list
DV78
Contents List
Page 2
Ove rv ie w
T he D
iV a D V78
is a c o m ple te ly n ew d e sig n p la tf o rm
t h a t s h are a s im ila r c ir c u it to p olo g y t o th e e arli e r
r e le a se d V add is V b a se d p la ye rs s u ch a s th e D iv a
8 8+ , D iv a 8 9, D V27.
T he p la ye r is b a se d a ro u nd a ccla im ed Z
ora n V ad dis
V c h ip se t c o u ple d to h ig h s p ecif ic a tio n W olf s o n D to A
c o n ve rte rs fo r L eft a n d R ig ht c h an nels .
P ow er s u pply b oard .
N on-s w it c h in g
M ain s p ow er a rr iv e s a t IE C in le t s o ck e t S KT1 a n d is
f ilt e re d b y E M C c h oke L I a nd Y c a p s C 3 a n d C 4,
m ain s s w it c h S W 2a/b s w it c h es b oth N egativ e a nd L iv e
p ha se s b efo re th e p o w er r e ach es th e m ain s s e le ct
s w it c h a t lo ca tio n S W 1 th e s w it c h a llo w s th e p rim ary
w in din gs o f t h e tr a nsfo rm er T
X 1
t o b e w ir e d in e it h er
P ara lle l o r S erie s c o nfig ura tio n .
T he B rid g e r e ctif y in g D io de p a ck a ge a t lo ca tio n D
1
f o rm s th e b asis o f th e c o n ve ntio na l p ow er s ta ge a nd
s u p plie s a V N 35V 6 ( -3 5 .6 v) to th e S w it c h m ode
s ta ge, tr a nsis to r T
R 1
is b ia se d b y 2 v7 Z ener d io de
D Z1
a n d a ll o w s fo r th e s e rie s Z ener d io des D Z2, D Z3,
D Z3
to s u pply t h e V N 13V 5 a nd V N 19V r a ils .
W e w ill a ls o s e e a s im ple A
.C p re sen t c ir c u it
th is is
u se d f o r d e la ye d o u tp ut r e la y o pera tio n a nd fa st r e la y
c lo su re u nder in te rr u pte d s u p ply c o nd it io ns th us
p re ve ntin g o p-a m p o ff s e ts f r o m r e ach in g t h e A udio
o utp ut s o ck e ts .
S w it c h m ode
T he s w it c h m ode s u p ply is fo rm ed a ro u nd th e
D riv e r/C ontr o l
c h ip I
C 1
U C384 3 ( u se d in r e gula tin g
m ode). T he c h ip is r e fe re nce d th e -“ 36.5 V s u pply li n e
a nd th e D ig it a l g ro un d D G ND , th e s u pp ly fo r t h e c h ip
i s fo rm ed b y t h e 1 2v Z en er a t lo ca tio n D
Z6
a n d c a n b e
s e e n o n P in 7 a s V C C. T he p ow er s u pply a llo w s fo r
t h e s w it c h -m od e to b e tie d th e to A udio s a m plin g
f r e que ncy f o r a n y g iv e n c o m patib le fo rm at.
Fig 1 P SU c lo ck c o ntr o l
Fs
F re q uen cy
s ele ct P
SU FS 1
P in 1 1
I C 305 a P
SU FS 0
P in 1 2
I C 30 5a P
SU CLK
O utp u t P in 5
o f I C 30 5a
44.1 k H z 0 0 44.1 k H z 4 8 k H z 0 0 48 k H z 8 8.2 k H z 0 1 44.1 kH z 9 6 k H z 0 1 48 k H z 1 76.4 k H z 1 0 44.1 k H z 1 92 k H z 1 0 48 k H z O th ers 1 1 OFF
The P SU s yn c s ig na l is d riv e n in to th e p o w er s u pp ly v ia
R esis to r R
9
if n o S yn c is p re se nt th e u nit is s e t to f r e e r u n x
d ue t o t h e R T/R C n etw ork a tt a ch e d to P in 4 .
I C 1
is r u nn in g in r e gu la te d m ode a n d m on it o rs th e v o lt a ge
o utp ut o n t h e + 5V a n d + 3V 3 D .C li n e s, th e t w o v o lt a ge s a re
s u m med b y T
R 8
a n d D riv e n in to th e V FB a n d C om p in puts
o f I C 1, th e V olt a ge is th en r e g ula te d b y c h ang in g t h e tim e
b ase o f th e P W M o utp ut a t p in 6 ( lo nger th e tim e b ase th e
l o w er t h e v o lt a ge), t h e P
W M s w it c h in g f r e q uen cy
is d riv e n
i n to t h e s w it c h -m od e tr a nsfo rm er b y th e h ig h s p e ed N m os
d evic e a t p osit io n M 1, R 5 is u se d to s e n se th e C urr e nt
a cro ss th e g a te o f th e N m osfe t a n d in t h e e ve n t o f a s h ort
c ir c u it w ill s a fe ly s h ut th e p ow er s u p ply d ow n. W e d eriv e th e
1 2v M ech s u pply fr o m th e o u tp ut o f M 1 u sin g th e U lt r a -fa st
D io d e a t lo ca tio n D 8 t o r e ctif y th e P W M lin e.
T he D .C o utp uts fr o m th e s w it c h m od e h a ve e xte n siv e
s w it c h m ode n ois e r e m ovin g f ilt e rs th ese a re s e en a s 1 00n
c a p s d ow n t o g ro un d a nd W ir e w ound in d ucto rs in s e rie s
w it h t h e s u pp ly r a il.
P ow er s u pply m ain b oard
A ll th e p ow er s u p ply r a il s a re s u pp li e d t o th e m ain b o ard v ia
t h e 3 2 w ay F FC c o nne cto r a t lo ca tio n C
O N100 1
.
T he D ig it a l s u pp li e s fr o m t h e s w it c h m ode s ta ge o f t h e
p ow er s u pply a rr iv e a s 3 V 3D , + 5V D a nd + 12V D w e a ls o s e e
t h e D is p la y b oard p ow er s u pp lie s a rr iv e a s -“ 1 9 V , - 9 a nd
-“ 13.5 V a ll o f th e s u pp li e s h ave a s e co n d s ta g e o f
i m ple m ente d o n th e b oard t o r e m ove a ll t r a ce s o f u lt r a -s o n ic
n ois e .
T he 3 V 3D r a il is th e m ain 3 V 3 r a il u se d to p ow er th e d ig it a l
c ir c u it r y ; + 5V D is u se d f o r a ll 5 v D ig it a l/ V id eo s u ppli e s t h e
+ 12V D is u se d fo r S ca rt s w it c h in g.
D iv a D v7 8 c ir c u it d es crip tio n
