Sony SEQ-555ES - Page 14

SEQ-555ES
Making of divided voltage
47k
from IC5o, Ei
(microcomputer D)
ICs10
Actual separation E/2
is by resistor, but
equivalently it is by
battery.
In the above figure, a high or low signal is applied to
ICsi9 © pin from the microcomputer.
ICsi9 does switching operation, and output voltage
is as follows.
When E/2 is 0
e
E(5.6V)
5V
Ea
E/2(2.8V) 0
ov
E(5.6V)
—_—
E
4.2V ———- 2/3e
Eb E/2(2.8V) 0
IV ———-2/3e
OV
E(5.6V)
3.4V ——_|/3e
Ec E/2(2.8V)
:
2 —1/3e
OV
Ea,
Eb
and
Ec
voltages
are
determined
as
shown
above.
However,
1/3e,
2/3e,
—1/3e
and
—2/3e
are
1/3
and
2/3
of
E
and
E/2
voltage
difference,
respec-
tively,
or
are
—1/3
and
—2/3
of
E/2
and
—E
voltage
difference.
Ea,
Eb
and
Ec
output
voltages
are
switched
by
ICs),
switch.
ICyo, (from microcomputer D)
switch signal
Es 4
switching signal
2/3E or —2/3E voltage
is constantly output.
OX 3X OX 3x
OY 3Y OY 3Y
ON ON ON ON
e Ye
A output voltage
~Ye
—e
B output voltage we
—Nwe
Voltage as shown above is output in the A, B outputs,
A, B and C voltage and 1/2E voltage are applied to
the LCD unit and IC’s.
The LCD display circuit is as follows.
O A voltage
O B voltage
When the potential difference at the two LCD pins
is more than 1.5V, it lights up.
The following is for A voltage only.
E
E/2(0)
ok
Interval when C 1/2E interval
voltage is applied