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CHAPTER
i.,
POWe-FfSlJPPLY uNIT
7-1. Technical characteristics
1)
Inputs
i)
AC adapior input
Ratedvoltage: 15.3V
.. __ ll'Lori<ing-'lQIJagarange:..L4.2.4",.t.6.51V-I _ _ _ _ _
ii)BatterYinpu!
Rated voltage: 9.6v
Working voltage range: BJ) ... 12.BV
2) Outputs
i) Output
~
Circtiiti
:ha'nie
';i
Rated load
,
5VVee
5VVBui
"
.
,
:1(2
2.12A
O.IA
*1: VBT
is an input voltage through circuit.
:<2: VBul is battery backed up.
If Vee is not. the load current is O.OiA.
ii) Recharge output
,
~24VVLCD·
O.022A
*1·
\/BT
2.7W
There are two modes of recharge; quick recharge and trickle
recharge, which gets in action when the
power
is off'to the 'personal
computer.
~
Quick recharge
Trickle recharge
Charge current
O.7BA
O.045A
Charge time
2 Hr
Continuous
7-2. Operational description
This DCIDC converter consists of two boards; one of which is the
control PWB and the other is power supply PWB.
2-1) Input filter
Fig.7
w
1 shows the input filter.
It
is a
high pass type filter that consists of CL 1, CL2, and C2. Noise
on the input line, radio interference from within the converter, and
conduction noise are suppressed in this circuitry.
+
IT' -="",---,.---,'L1
r--.--l
Fig. 7-1
-38-
2-2) 5V, VCC circuit
Fig.i:2
shows the 5\i,
vccCi~quji
..
B~16.5VDC supplied Irom the ACadaptor or the battery is dropped to
5V in TR4 to supply the regulateid 5V~ The' transistor TR4 is switched
at
110KHz Lisin-g the' control signal from! lei of the control PWB to
convert t~e De input into high frequencY~square waveform,
-them
rec-
tiliedand smoothed by D2, L2, and Cl0.
To regulate the output voltage, a -fluctuation in the supply line is
detectetf: and divided
by
means of the ;resistors Ri,
R2,
and
VR1
within the control
PWB iNhieh is then sent to, the comparato(input in
-~JCrWhere'1heONWlCllfi(jrrR4'i$·contrcilled by the drive Signal that
error amplified
by
the error
amp
within' lei. '
On and off 01 Vee is controlled b~ CPU (IC5).
~~
p'
L...
,
n
I ,
7
e
'9
•
W
W
<)
'"
e
, -
~
~
·TR3
Yo
!l
.
•
·RlI
"
"
II
,
"
0 0
z z
" "
Fig. 7-2
.
> > > >
j
'y'
, Y'
•
14 1 y13
W W
W
t--
e,' !
+
'TAt
<
F~
F
M
0
'R25
'R24
0
M
~
I-
M
r :
·Iet
~
~
~6~
i C
~
+
?
i3T
f-i
f-
'CaB
-
--'VV\,-
·A31
,
2 'A2
'Al
'VA','
I
vee,
ADJ
I
Fig. 7-3
.---'
p
h
I '
i'
'.2'_.12
~
5' Iii
I·~~!!H.'_
w
e
0 0
,
, Y"
5
y"f·
P f-L
~
r--
~
: I
flJ
L
'V
¥
~
!l
I
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