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at
http://www. PC-1500.info
5. CIRCUIT DISCRIPTION
• Power
>upply
The CE·1 58 is driven by
the
PC·ISOO power (Vee) and Ni-Cd
battery,
o
r
through an
AC
adapter.
The
input
is
fed
through the DC-DC
converter
to
reach
VDO (+5.0
V),
VC+
(
+9.0
V),
and VC-
(-
9.0 V).
Notel
.
Oat"'
rl
nc
1
i11
cr(ESD-H-14B}
,__,-<>
V
C-(-
9.0V)
1W 100Cl
EA21Ay
100
1
X2
+
r--~--.
l
ow battery
de
tection
Circuit.
,__,-<>
VC+
(+
9.0V)
DC-DC
0.1
)If
P.GNO
-+--~'----;,_;....~
'---·
S.
GND
16V
220µF
ConYOtOI'
1---0
VD
oC+
5.0
V
}
Circuit
,__,..-<)
GNO
•
Low
battery detection
circuit
4
Battery
condition
is
monitored
by
the
circuit
sketched
below. Signals detected
are
checked
by
the
CPU for
each
receiving
and
transmilting
step through
LH58
J
I's PA5
1/0 port.
Besides,
SW6
reaches the GND
level
with power
on,
thereby turning
on 2SA937R
to
keep
the
low battery
detection circuir in
function
.
+
SOV
1 1rF
2SA937R
(SW6}
3 .:lKO
560 KO
150
H438LL01
Vee
100KO
RV22KO
2SC2021RS
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