Sharp ZQ-3000 - Page 3

2. Regulator
(Internal block diagram)
3. Detector
(Internal block diagram)
VDD
OUT
VSS
4.
Low
voltage
detection
method
®
In
this
model,
a
warning
is
given
only
to
the
main
battery
exhaus-
tion,
not
given
to
the
backup
battery
exhaustion.
The
main
battery
exhaustion
is
detected
in
the
circuit
shown
below:
YCC
E01
KI8
(Nch open-dagin type)
GND
aa
ZQ-3250
1) Caution level (detection voltage: About 4.8 ~ 5.3V)
When the caution level is detected while displaying, the low battery
symbol ([BATT |) is lighted.
When the caution level is detected on supplying the power to the
set or on pressing the reset switch, the battery replacement indica-
tion (PLEASE REPLACE THE OPERATING BATTERY !) is dis-
played for about 4 sec.
When the caution level is detected while sounding the alarm or key
input sound, the alarm sound or key input sound is stopped.
2) Fatal level (Detection voltage: About 4.4 ~ 4.8V)
When the fatal level is detected while displaying, the whole system
is turned off.
When the fatal level is detected, on supplying the power to the set
or on pressing the reset switch, the whole system is tumed off.
When the fatal level is detected while sounding the alarm sound or
key input sound, the alarm sound or key input sound is immedi-
ately stopped. After 100ms, the voltage is restored and the next
process is performed.
When the fatal level is detected while the power is off, pressing the
key will not supply power to the set. The reset key is also
disabled. (Until the battery is replaced.)
[Note] Since low voltage detection is not performed for the memory
protection battery, please note the battery replacement label
and replace when necessary.
5. Alphabet: Caps/Low
Caps/Low of alphabet can be selected by pressing the [CAPS
key.
When the power is supplied by pressing the key, Caps ts
selected. (Caps symbol is lighted.)
@ Circuit
© This circuit has no hysteresis characteristics.
VCC
EOI
RESET SW key
® Software
1. Caution level is detected every 0.5sec. (FO1 = GND)
2
In normal cases, only the fatal level is detected. (EO1 = Vcc)
3. Even when the system is off, the fatal level is detected.