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KSC-4 (RAPID CHARGER)
4) Battery Recognition Circuit
KNB-4:
"L"
CURRENT
LIMITING
>
toQ6
NORMALLY : "L"'
INPUT
OUTPUT
BATT.
|AIB;/C/DiE|FIG
None { t f t ft fHiHi cht
SEE cur
KNB-3A
}H/ LILITH] H]LIH
———
ais
|
KNB4
[H[H{L{L[H|[L[H
5
1
2)
Lp roars
|
Table 3
,
| kne-3A/KNB-4 py
Fig. 3 Battery Recognition Circuit Block Diagram
5) Charging Current Limiting Circuit
This circuit receives the output of the battery recogni-
tion
circuit and
limits the charging current according to
the type (current capacity) of battery.
The
charging
current
ICR
is detected
as a valtage
drop across
R1
(0.15Q},
which
is provided
to pin 3 of
the
operational
amplifier
1C4(1/2)
: LA6393A.
Pin 4
BATT.
| O5 | Q6 | VrEF
|IcR MAX
receives a reference voltage (VREF) used as a comparison
KNB-3A | OFF | OFF | 0.28V | 1.8A
standard
for limiting the charging current. The VREF
is
KNB-4 | ON | OFF | 0.36V | 2.4A
changed by ON and OFF by QS and O6. (See Table 4.)
When a KNB-3A or KNB-4 is charged, Q6 is off. Pin 2
Table 4
of I1C4 provides ''L'' output when VREF
VCR, stopping
the operation of the chopper regulator (IC1
: STK772B)
C}<—
IcR :CHARGING CURRENT
VCR
=0.15ICR
Fig. 4 Charging Current Limiting Circuit Block Diagram
96
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