Service manual
6. Power supply
6-1. Kinds
of
power supplies
..
-
Voltage
Dueription
s
upply
range
VGG
4.0
-4.7V
•
Lo
gie driving
power
whieh is
on
while
th.
sy"lm
is
not
operating. P
ower
is
supplied
to
th.
el'iipl
thet
M.d
protei:>
tion.
(1)AAM16KB
Memory
proteclion
(2) LU57
813P
A"I
'lim'
timer
I
nd
wake-up
timer
prottlC1ion
(3)
HD61102
011911v
data
protection
whieh
II
rlquirid
to
aetiv.te
Ihe
display.1
pOwer..on Ihlll"
auto
pOwer-off.
(4) LA38041
To
m.lntain
thl signal level
of
sud!
II
Ih'
memory select signal
at
I
non·
active level.
vee
4
.0
-
4.7
V
• Logic driving
po_r
whieh is
shut
off
when
the
Iyrtem
is
turned
off.
Power
II
supplied
to
the
chips
met
do
not
need
prOll(:tion when
the
system is off.
11)
ROM
256Kbit
12)CPU
SC7852, LH5803
13)
H061203(S)
LCD
eommon
driver
ehip
14)
TCSS76F
UART
LSI
VEE
Approx.
•
For
e
r"llon
of e
low
voltage
10
thl
_
8.SV
LCD
driVil
volUige
and
the
RS·232C
Int.rfee.
sign.l
l.
VOO
Approx
•
For
er.llion
of
I high voltage
to
th.
6.0V
RS
-232C
intlrflee
li91'1811.
Thil
voIUlQI,
how
..... r,
II
supp
li
ed
when
PA
IME
II
at
I high
l.veIIRS·232C
is ehosen)
and
shut
off
whln
PRIME
is
• low level.
6-2. Power generation method
The
fo
llowing power supply sources are used
to
generate
the above
power
requiremen
u,
(1)
Internal dry
batt
ery cells
(x
4)
(2)
Through the
AC
adaptor
(3)
Supplied through the VBAT
of
the system bus
A high voltage supply l
evel
is
used by the
PC-
1600.
(i) V
GG
A
vo
ltage of abo
ut
4.7V
is
nonnally supplied
from the above source, The voltage drops when
the level
of
power supply decreases,
(ii)
vec
VGG
is
supplied through this line, when BFO is
at
a low
lev
el
or
AC
L
is
at
a high
le
vel.
vec
is
not
supplied when
the
system
is
off.
-
10
-
(iii) V
EE
VE
E
is
supplied when the system
is
turned on.
(iv)
VDD
VOO
is
supplied when the PRIME
output
is
at a
high
level
with the system on .
6-3. System-on/system-off
The on/off state of
the
system
is
cont
rolled by the
LU
57B13P. The on/off
state
of
the system
is
seen on the
BFO output. When BFO
is
low, the system
is
on and
vee
and VEE are available. When
the
system is off, no
power
is
supplied exce
pt
VGG,
(1) System.off to system-on
There are
fi
ve
ways.
(i)
U
se
of the BREAK/ON key
Iii)
By
means
of
the
wa
ke-up function
Possible
to
disable with mask
(iii)
By
means of
the
RS
·232C interfacing CI signal
~
(iv)
U
se
of
the
AL
L RESET switch
(AC
L signal)
located on the back
of
the
PC
·
l600
(vi
By means of the reset input from the
CE
·
16OQP
Normally, the system
is
turned off with (i).
(2)
System-on
to
system-off
There are two ways.
(i)
By
means of
the
Z·
BO
command
(ii)
By
means
of
the weak
banery
detect signal
(03)
1. System operation
1-1. System-off operation
lSls
operated by VGG, except for the LU57813P, are
assigned
to
protect their contents,
F
or
the
LU
57813P,
the
real timer needs
to
be
revised when
the system
is
off. So,
an
interrupt
is
sent
to
the
LU57813P
by the internal timer every 0,5 second to revise the
real
timer.
When
seconds are carried
to
a minute, the time
is
verified with the wake·up timer and the alarm time. There·
fore, a system clock (153.6KHz
or
307.2KHz)
is
issued on
FOUT
of
the
LU57813P avery 0.5 second.
The system starts
to
rise when 01
of
the
el
connected
subcontroller remains high for more than
the
predeter.
mined time; the system wake·up
is
also possible by the CI
input
of
the
RS
·232C interface which
is
input
at
0.5
second interval
s.
But, if the system
is
forced off because
of
a weak battery
conditiOrt
(03
input
at
high),
the
0.5 second interval timer
interrupt
is
not
activated even if the weak battery con-
dition
is
cleared,