Ricoh Aficio FX10, Руководство по обслуживанию

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1.6.2. Memory Back-up Circuit
The +5VBAT supply from the lithium battery [A] backs up the system RAM
which contains system parameters and programmed telephone numbers,
and the real time clock in the cpu. The 5RTCCS signal tells the cpu whether
the back-up power (+5VBAT) is coming from the battery or from the +5V
power supply.
A rechargeable lithium battery [B](available only for Europe/Asia) and the
dc/dc converter on the FCU back up the DRAM (SAF memory) for one hour,
if there is data in the SAF memory and the power is switched off. While the
main power is on, the +5V supply recharges the battery. The battery re-
charges in about one week.
The battery [B] generates about 3 volts (max. 3.2 volts). The dc/dc converter
(IC12) lifts this voltage to 5 volts so it can be used as the +5VD supply for
SAF backup. The CPU monitors the voltage of the +5VD supply with the
1VDET signal. When the battery has run down, and the voltage is lower than
4.4 volts, the CPU stops the dc/dc converter by dropping 1SAFFG to low and
the machine stops backing up the memory.
There is no battery switch for the battery [B].
F C U
D R A M
+ 5 V
Q 8
IC Card
D C / D C
Converter
[IC15]
+ 5 V
+ 5 V
+ 5 V B A T + 5 V D
P O W E R S
5 R T C C S
+5VBAT
System
R A M
Switching
Circuit
1 V D E T
1 S A F F G
F C I P 2
+
-
+ 5 V D
[A]
[B]
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June 10th, 1997 OVERALL MACHINE INFORMATION
POWER DISTRIBUTION
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